Search

This paper reviews the characteristics of membrane distillation technology and the current research progress and hot issues, and compares the latest research progress of membrane distillation technology in terms of membrane material characteristics, membrane wetting and pollution, membrane material modification, research and application in oil and gas field produced water, etc. Membrane distillation technology was found to have great potential for the treatment of oilfield talent effluent, and the energy consumption limitation of membrane distillation technology can be improved by using low-grade thermal energy and coupling other processes. The improvement of membrane materials to obtain high flux and pollution resistant hydrophobic membranes is the key to achieve industrial application of membrane distillation technology. [ABSTRACT FROM AUTHOR]

The inhibiting efficiency of three newly synthesized organic compounds:5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1228), 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1227) and 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1226) in oilfield produced water on the corrosion of carbon steel has been examined via electrochemical measurements; potentiodynamic polarization (PDP) and electrochemical impedance (EIS) techniques. The adsorption of these compounds on the surface of carbon steel followed Langmuir isotherm. In addition, the surface morphology of uninhibited and inhibited carbon steel was examined by Atomic Force Microscopy (AFM), observing surface improvement when carbon steel samples exposed to the inhibited corrosive solutions. The average surface roughness (Ra) in oilfield produced water solution in the presence of 0.5 mM of HM-1228 inhibitor was 138.28 nm compared to the uninhibited surface 571.62 nm. To explore the corrosion inhibition mechanism, quantum chemical calculations and Monte Carlo simulations were utilized. The HM-1228 inhibitor demonstrated the highest corrosion inhibition efficiency at 94.8% by PDP measurements. The higher corrosion inhibition of compound HM-1228 can be attributed to the presence of di-N-ethyl groups that enhance both electron donating ability and lipophilic properties. [ABSTRACT FROM AUTHOR]

The inhibiting efficiency of three newly synthesized organic compounds:5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1228), 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)-2-thioxodihydropyrimidine-4,6(1H,5H)-dione (HM-1227) and 5-((4'-(dimethylamino)-[1,1'-biphenyl]-4-yl)methylene)pyrimidine-2,4,6(1H,3H,5H)-trione (HM-1226) in oilfield produced water on the corrosion of carbon steel has been examined via electrochemical measurements; potentiodynamic polarization (PDP) and electrochemical impedance (EIS) techniques. The adsorption of these compounds on the surface of carbon steel followed Langmuir isotherm. In addition, the surface morphology of uninhibited and inhibited carbon steel was examined by Atomic Force Microscopy (AFM), observing surface improvement when carbon steel samples exposed to the inhibited corrosive solutions. The average surface roughness (Ra) in oilfield produced water solution in the presence of 0.5 mM of HM-1228 inhibitor was 138.28 nm compared to the uninhibited surface 571.62 nm. To explore the corrosion inhibition mechanism, quantum chemical calculations and Monte Carlo simulations were utilized. The HM-1228 inhibitor demonstrated the highest corrosion inhibition efficiency at 94.8% by PDP measurements. The higher corrosion inhibition of compound HM-1228 can be attributed to the presence of di-N-ethyl groups that enhance both electron donating ability and lipophilic properties. [ABSTRACT FROM AUTHOR]

With the large-scale application of polymer flooding technology, the polymer concentration in produced water is increasing, which leads to incomplete regeneration of filter media by gravity field hydraulic backwashing technology only. In this study, the high-gravity backwashing technology is constructed by coupling gravity field and swirl field, which promotes the development of the oilfield. Based on the cascade theory, this paper establishes a mathematical expression of radial collision force in the high-gravity backwashing process in the vortex tube and solves a mathematical equation of high-gravity backwashing velocity gradient G based on the efficient zone of collision force action. Meanwhile, based on the discrete element method and computational fluid dynamics theory, the inter-particle collision regulation of the high-gravity backwashing process is simulated by the coupled FLUENT-EDEM method, and the high-efficiency zone of the backwashing process is verified. In this high-efficiency zone, the theoretical and simulated values of velocity gradient G for different high-gravity values match well, with differences ranging from –5.8 % to +7.1 %, indicating that the theoretical model of high-gravity backwashing is correct. When the high-gravity value is 210–240 g, the total impulse of the filter bed per unit time reaches a great value, and the backwashing velocity gradient G is 3047.1 s−1, which is much larger than the G value of combined air-water backwashing. The high-gravity backwashing technology breaks through the technical bottleneck of low efficiency in the action of the gravity field. It enriches and develops the gravity field hydraulic backwashing technology of the filter bed. • A new method of high-gravity backwashing is proposed, and a theoretical model of high-gravity backwashing is constructed. • The mathematical equations particle impact force and velocity gradient in high efficiency area of high-gravity backwashing are established. • The coupling method of FLUENT-EDEM is used to study the backwashing process, which provides a new idea for the backwashing of traditional water treatment filter bed. [ABSTRACT FROM AUTHOR]

Chemical flooding, as the main method to improve recovery, has been widely applied in the oil- fields and has achieved good results in enhancing and stabilising crude oil recovery, but the existing chemical flooding technology are limited by reservoir geological conditions, cost effectiveness and technology level, and the recovery rate of crude oil in some oilfields is not satisfactory. The study proves that nano oil repellents can enhance crude oil production by reducing oil-water interfacial tension and changing rock wettability, are stable under complex reservoir conditions and have great potential in the field of recovery enhancement. The existence of nano-displacement agent is divided into three categories: nano-powder, nano-Pickering emulsion and nano-emulsion, and the research progress of nano-powders and nano-emulsions based on nano-SiO2, summarises the advantages and problems of nano-oil repellents, analyses the mechanism of nano-oil repellents and outlines the development trend. [ABSTRACT FROM AUTHOR]

In northern Afghanistan, the Kashkari oil field's first production well was drilled in 1976, and by 1979, there were a total of ten wells drilled in the area. According to the results of surveys and calculations conducted by research institutions, the total amount of original oil in place (OOIP) in the Kashkari oil site was around 140 million barrels (MMbbls). Therefore, a method to increase the total amount of recoverable oil in the Kashkari oil field by low-salinity water flooding is presented in this study. First, the oil extraction method by low-salinity water injected into the underlying petroleum storage tank was examined by both a laboratory core flooding test and a numerical simulation model. Laboratory conditions (temperature, pressure, rock properties, and oil properties) were designed to mimic those of the Kashkari oil field. Additionally, different injection (Inj) and production patterns were considered to achieve the best results. Next, results obtained from the laboratory and computer simulations were compared. Then, the total amount of recoverable oil was calculated using the low-salinity water flooding method. Based on the findings, details of the simulated model were applied to the Kashkari reservoir model for extracting oil by injecting low-salinity water in the oil field. As a result, an amount of 10.3 MMbbls, which is about 7.5% of the field, was produced. [ABSTRACT FROM AUTHOR]

Hydraulic fracturing utilizes pressurized liquid typically consisting of water, proppants, and a multitude of chemical additives, in order to fracture petroliferous strata to extract natural gas and oil. In this process, a vast amount of wastewater is produced. This water is heavily contaminated, which renders it unusable outside of direct reuse, without extensive treatment being performed. Typically, various sophisticated analytical techniques are involved in the characterization of both waste and treated waters, increasing the cost and the complexity of the management efforts. The article discusses the constituents found in oilfield wastewater, the methods used to identify and quantify these constituents, and the present management methods. Additionally, we introduce total organic carbon and conductivity analyses as surrogate measurements of overall water quality. Total organic carbon and conductivity are established bulk measurements, which can be used to facilitate rapid decisions regarding the treatment and greater utilization of flowback and produced oilfield wastes. The application of the proposed surrogates could be used to streamline the current myriad of complex and expensive measurements. This would improve operational efficiency with respect to wastewater management in the energy sector. [ABSTRACT FROM AUTHOR]

Antimony deposits contain little Sn, whereas Sb and Pb are not the principally contained metal of granite-related Sn deposits. The Danchi Sn-metallogenic ore belt (DSOB) in southwestern China is characterized by Sn-Sb-Zn-Pb co-enrichment, yet the triggers are poorly constrained. The Beixiang deposit in the southern DSOB consists of stage I Sn-Zn and stage II Sb-Pb-Zn mineralization. Here, we analyzed the cassiterite U-Pb age, fluid inclusion H-O and sulfide Pb-S isotopes, and calcite trace elements of the Beixiang ores. By comparing with the Dachang and Mangchang Sn-polymetallic ore-fields within the DSOB, we constrained the timing of regional mineralization and revealed the processes causing the Sb-Pb co-enrichment. The cassiterite U-Pb dating yielded 90.6 ± 4.5 Ma (MSWD = 2.6), similar to the ages of the Dachang and Mangchang ore fields, indicating the Late Cretaceous mineralization event throughout the DSOB. The fluid inclusions from stage II ore have δ18OH2O (−2.8 to −7.8‰) and δDV-SMOW (−90.5 to −59.3‰), and the synchronous calcite features have low REE contents, upward-convex REE patterns, and weak Eu anomalies. These suggest that the ore fluids were derived from meteoric water and oil field brine, which dissolved S and Pb from local strata as recorded by sulfide sulfur (δ34SV-CDT = −6.2 to −4.0‰) and Pb isotopes. However, calcite from the stage I ore have higher REE contents and (La/Yb)N, with strong positive Eu anomalies, indicating that the Sn-rich ore fluids were released by greisenization of granite. Overall, we suggest that the combination of granitic magma- and oil field brine-derived fluids, rich in Sn-Zn and Sb-Pb-Zn, respectively, caused the co-enrichment of Sn-Sb-Pb-Zn in Beixiang and throughout the DSOB. [ABSTRACT FROM AUTHOR]

Polymer flooding is drawing lots of attention because of the technical maturity in some reservoirs. The first commercial polymer flooding in China was performed in the Daqing oilfield and is one of the largest applications in the world. Some laboratory tests from Daqing researchers in China showed that the viscoelasticity of high molecular weight polymers plays a significant role in increasing displacement efficiency. Hence, encouraged by the conventional field applications and new findings on the viscoelasticity effect of polymers on residual oil saturation (ROS), some high-concentration high-molecular-weight (HCHMW) polymer-flooding field tests have been conducted. Although some field tests were well-documented, subsequent progress was seldom reported. It was recently reported that HCHMW has a limited application in Daqing, which does not agree with observations from laboratory core flooding and early field tests. However, the cause of this discrepancy is unclear. Thus, a systematic summary of polymer-flooding mechanisms and field tests in China is necessary. This paper explained why HCHMW is not widely used when considering new understandings of polymer-flooding mechanisms. Different opinions on the viscoelasticity effect of polymers on ROS reduction were critically reviewed. Other mechanisms of polymer flooding, such as wettability change and gravity stability effect, were discussed with regard to widely reported laboratory tests, which were explained in terms of the viscoelasticity effects of polymers on ROS. Recent findings from Chinese field tests were also summarized. Salt-resistance polymers (SRPs) with good economic performance using produced water to prepare polymer solutions were very economically and environmentally promising. Notable progress in SRP flooding and new amphiphilic polymer field tests in China were summarized, and lessons learned were given. Formation blockage, represented by high injection pressure and produced productivity ability, was reported in several oil fields due to misunderstanding of polymers' injectivity. Although the influence of viscoelastic polymers on reservoir conditions is unknown, the injection of very viscous polymers to displace medium-to-high viscosity oils is not recommended. This is especially important for old wells that could cause damage. This paper clarified misleading notions on polymer-flooding implementations based on theory and practices in China. [ABSTRACT FROM AUTHOR]

The dump flooding technology comes from offshore oil fields. It is necessary to increase the production of oil by water injection when fracture-cavity reservoirs in Xinjiang enter their middle and later stages. Lack of water sources in the desert area and the presence of heavy upper water layers encourage further research into the application of this technology. The dump flooding technology can eliminate the need for specialized injection wells and reduce the consumption of oil fields in the surface water sources, which may significantly aid in the development of the local economy and environment. In China, the research on dump flooding is still in its preliminary phase. Hence, there is no complete flow model for gravity flow and no optimization design software to optimize the development effect. This article sets up a flow model of a water layer-well-fracture unit by key local nodes. The key nodes, such as some perforating water layer, the bullet hole or the water valve, were simulated using the COMSOL software. The flow equations of each node were coupled together for the system-wide flow coupling model to verify the whole system by the numerical simulation, which needs Eclipse to run. The results of the research can be used to predict the water injection rates and formation pressures, and also provide a reference and a basis for the optimal design of water injection. [ABSTRACT FROM AUTHOR]

• B. velezensis demonstrated effective inhibition of X65 steel corrosion. • Biomineralized film prepared by B. velezensis exhibited corrosion resistance. • This paper offered a more environmental solution to corrosion inhibition. The issue of material failure attributed to microbiologically influenced corrosion (MIC) is escalating in seriousness. Microorganisms not only facilitate corrosion but certain beneficial microorganisms also impede its occurrence. This study explored the impact of marine B. velezensis on the corrosion behavior of X65 steel in simulated offshore oilfield produced water. B. velezensis exhibited rapid growth in the initial stages, and the organic acid metabolites were found to promote corrosion. Subsequently, there was an increase in cross-linked "networked" biofilms products, a significant rise in the prismatic shape of corrosion products, and a tendency for continuous development in the middle and late stages. The organic/inorganic mineralized film layer formed on the surface remained consistently complete. Metabolic products of amino acid corrosion inhibitors were also observed to be adsorbed into the film. B. velezensis altered the kinetics of the X65 steel cathodic reaction, resulting in a deceleration of the electrochemical reaction rate. The mineralization induced by B. velezensis effectively slowed down the corrosion rate of X65 steel. [ABSTRACT FROM AUTHOR]

• PMM as a promising substratum to meet Canadian oil sands' zero waste goal and SDGs. • Both low and high strengths produced waters were efficiently reclaimed. • Chemisorption, supported by AD, along limited physical adsorption were key findings. • High conductivity, presence of Geobacter and Methanosaeta indicate DIET during AD. • The 'microbial dark matter' (∼50%) warrants further investigations for microbial activities. Nature-based solutions are encouraged for treating oilfield produced water from oil and gas extraction, a crucial undertaking that aligns with the Canadian oil sands industry's ambitious goal of zero waste, and the globally recognized Sustainable Development Goals (SDGs) pertaining to water conservation and ecosystem preservation. This study explored the use of peat-mineral mix (PMM), a leftover of inevitable oil sands mining, for treating low and high-strength wastewaters during biofiltration, which contained large molecular weight (44.3 kDa), which include alcohols, aliphatics, aromatics, and ketones, and can impart high toxicity to both fauna and flora (MicroTox: 99 %). The breakthrough curve indicated an effective initial adsorption phase driven by advection within the column dynamics. For complete organics removal and mechanistic insights, the wastewater was re-circulated in a continuous mode for up to 42 days. Here, we found that chemical oxygen demand was reduced from ∼85,000 mg/L to ∼965 mg/L). Kinetics investigations along with physicochemical characterization of PMM and wastewater suggested that chemisorption and anaerobic digestion contributed to the overall removal of contaminants. Chemisorption, led by hydrogen bonding and hydrophobic interactions, was the dominant mechanism, with a limited contribution from physical adsorption (surface area: 2.85 m2/g). The microbial community within the PMM bed was rich/diverse (Shannon > 6.0; Chao1 > 600), with ∼ 50 % unclassified phylotypes representing 'microbial dark matter'. High electric conductivity (332.1 μS cm−1) of PMM and the presence of Geobacter , syntrophs, and Methanosaeta suggest that direct interspecies electron transfer was likely occurring during anaerobic digestion. Both low and high-strength wastewaters showed effective removal of dissolved organics (e.g., naphthenic acids, acid extractable fraction, oil and grease content), nutrients, and potentially toxic metals. The successful use of PMM in treating oilfield produced water offers promising avenues for embracing nature-based remediation solutions at oil refining sites. [Display omitted] [ABSTRACT FROM AUTHOR]

The Si/N-DLC films with different Si and N contents were deposited and the corrosion behaviors in the simulated CO 2 -saturated oilfield produced water was mainly investigated. Results reveal that Si/N-DLC films improves dramatically the corrosion resistance of the substrate. This attributes to not only the channel blockage caused by diffusion of corrosion products, being composed of silicon oxide (SiO x) and metal oxide, but also the stronger support of increased roughness induced by N to the aggregated corrosion products, implying that the Si/N-DLC film are a self-healing protective film. These results provide theoretical guidance to develop the DLC films for anti-corrosive applications. • A self-healing Si/N-DLC film for corrosion protection was deposited by PECVD technology. • Corrosion behaviors and its stability of Si/N-DLC films in simulated CO 2 saturated oilfield produced water was studied. • Si/N-DLC films improves significantly the corrosion resistance of the substrate in oilfield environment. • Mechanism attributed to diffusion channel blockage and strong support for aggregating corrosion products. • Theoretical guidance to develop the DLC films for anti-corrosive applications was provided. [ABSTRACT FROM AUTHOR]

Fluorescence spectroscopy is a powerful tool to determine polycyclic aromatic hydrocarbons (PAHs) owing to the strong endogenous fluorescence of these compounds. However, the presence of unknown interferences and overlapped spectra hinders the accurate determination of PAHs in oilfield produced water. Moreover, surfactants frequently coexist in oilfield produced water and will seriously affect the fluorescence signals of PAHs. Herein, a new methodology applying third-order calibration to process four-way (4D) fluorescence data was proposed to solve these problems and achieve accurate determination of pyrene, fluorene, phenanthrene, and fluoranthene as an example in oilfield produced water. The methodology is based on excitation-emission matrix fluorescence modulated by different concentrations of sodium dodecyl benzene sulfonate (SDBS) in the analyzed samples. The 4D fluorescence data were processed by third-order calibration methods including four-way parallel factor analysis (4-PARAFAC) and alternating weighted residue constraint quadrilinear decomposition (AWRCQLD), and the results were compared with those of second-order calibration methods. It was proved that third-order calibration was capable of accurately identifying and quantifying PAHs together with SDBS in oilfield produced water, which has better quantitative results and figures of merit compared to second-order calibration. This study provided a new approach to generating 4D fluorescence data and opened up an avenue for the accurate determination of PAHs in complex oilfield produced water with surfactants. [Display omitted] • 4D excitation-emission matrix fluorescence data modulated by SDBS was first constructed. • Chemometric multi-way calibration algorithms were used to process the 4D fluorescence data. • The proposed strategy could determine PAHs in oilfield produced water with surfactants. • Third-order calibration has more robust performances than second-order calibration. • SDBS could be successfully predicted as an added bonus in third-order calibration. [ABSTRACT FROM AUTHOR]

During the exploitation of oil reservoirs with highly mineralized waters, water separated from oil is pumped back into the reservoirs, which in some cases leads to an increase in ambient salinity and limits the possibility of application of biotechnologies for the enhancement of oil recovery. The microbial community of such oil fields has been relatively scarcely studied. Two strains of halophilic hydrocarbon-oxidizing bacteria, Halomonas titanicae TAT1 and Marinobacter lutaoensis KAZ22 were isolated from oil fields with mineralized formation water. Their physiological and genomic characteristics determining their presence in these habitats and the possibility of biotechnological application were investigated. The strains H. titanicae TAT1 and M. lutaoensis KAZ22 grew aerobically on crude oil in the temperature range from 4 to 42 and from 22 to 55°C, respectively, and had growth optima at salinity levels of 2–12 and 5–10% NaCl (wt/vol). Phenomenological observations of the degradation of oil n-alkanes were confirmed by the detection of three genes (alkB1, alkB2, and almA) encoding alkane1-monooxygenases in the genome of strain KAZ22 and of one alkB gene in the genome of strain TAT1. In the genome of the H. titanicae TAT1, all the genes for formation of osmoprotectants betaine, ectoine, and hydroxyectoine were annotated, and in the genome of M. lutaoensis KAZ22, the genes for the formation of ectoine and hydroxyectoine were annotated. The growth of strain KAZ22 on oil was accompanied by a decrease in the surface tension of the medium by more than 20 mN/m. Due to the absence of the nirK nitrite reductase gene, anaerobic growth of strain H. titanicae TAT1 in a medium with acetate and nitrate resulted in accumulation of ~100 mg/L of nitrite, which can inhibit the growth of sulfidogens. Considering the biological features of the strains and the results of genome analysis, injection of nitrate and strain H. titanicae TAT1 can be recommended for bioaugmentation of oil reservoirs with mineralized formation waters to suppress corrosion and decrease sulfide content, and injection of M. lutaoensis KAZ22, for remediation of oil pollution and increasing oil recovery from reservoirs. [ABSTRACT FROM AUTHOR]

The effects of oil and gas production on adjacent groundwater quality are becoming a concern in many areas of the United States. As a result, it has become increasingly important to identify which aquifers require monitoring and protection. In this study, we map the extent of groundwater with less than 10,000 mg/L TDS both laterally and vertically near the Elk Hills, Buena Vista and Coles Levee Oil Fields in the San Joaquin Valley, California and note evidence of effects of produced water disposal on salinity within the Tulare aquifer. Subsurface maps showing the depth at which groundwater salinity is less than 10,000 mg/L (or Base 10K) in the Tulare aquifer are generated using geophysical logs and verified by comparison to water sample analyses. The depth to Base 10K ranges from 240 m (800 ft) in Elk Hills to 800 m (2650 ft) in the adjacent Buena Vista syncline and is 670 m (2,200 ft) deep in the Coles Levee area to the east. Log-calculated salinities show a relatively smooth increase with depth prior to disposal activities whereas salinities calculated from logs collected near and after disposal activities show a more variable salinity profile with depth. The effect of produced water injection is represented by log resistivity profiles that change from low resistivity at the base of the sand to higher resistivity near the top due to density differences between the saline produced water and the brackish groundwater within each sand. Continued post-disposal logging in new wells in the 18G disposal area on the south flank of Elk Hills shows that injected water has migrated approximately 1,200 m (4,000 ft) downdip (south) over a period of 20 years since the inception of disposal activity. [ABSTRACT FROM AUTHOR]

In this study, the effect of Alcaligenes sp. on the corrosion inhibition of sulfate-reducing bacteria (SRB) was evaluated and the mechanism was discussed from the aspects of Alcaligenes sp. metabolites, transform sulfide ability and the effect of corrosion product films. Alcaligenes sp. converted sulfides produced by SRB to S 2 O 3 2-, which accumulated and converted to SO 4 2-. The antimicrobial substances produced by Alcaligenes sp. inhibited the growth of SRB. The protein/polysaccharide had a certain corrosion inhibition effect and the corrosion product film was denser and more continuous. The combined effects of multiple factors inhibited the corrosion induced by SRB. ● Alcaligenes sp. and its metabolites effectively inhibited SRB-induced corrosion. ● Inhibition mechanism was discussed in terms of metabolite, transform sulfide and corrosion product. ● Green protection to inhibit MIC by "bacteriostasis with bacteria" was perfected. [ABSTRACT FROM AUTHOR]

Using high-salinity oilfield water as the annulus protection liquid base fluid can easily increase the risk of corrosion and cracking of tubing and casing steel. Therefore, it is necessary to evaluate the corrosion risk of P110 S steel in the oilfield water annulus protection liquid. Firstly, the chemical components of oil field water and P110 S steel were analyzed. Then, the field conditions were simulated by using a high-temperature autoclave. The weightlessness corrosion and four-point bending experiments were carried out under the temperature of 200 ℃, CO2 partial pressure of 10 MPa and H2S partial pressure of 2 MPa, and the morphology and composition of corrosion products was analyzed by using SEM and EDS. Finally, the cross-section of the sample was analyzed. The results show that P110 S steel does not suffer from stress corrosion failure under high temperature and highacid conditions. The corrosion rate is 0.098 5 mm/a, severe pitting and local corrosion can be observed on the surface of the sample. Cross-sectional analysis shows that the thickness of corrosion product film on the sample surface is 63 μm, and the metal matrix is corroded seriously. P110 S tubing and casing steel faces a greater risk of corrosion failure under this working condition. In order to suppress the corrosion damage of the pipes, it is recommended to use fresh water or low-salinity well site water as the annulus protection liquid base fluid. [ABSTRACT FROM AUTHOR]

Groundwater total dissolved solids (TDS) distribution was mapped with a three-dimensional (3D) model, and it was found that TDS variability is largely controlled by stratigraphy and geologic structure. General TDS patterns in the San Joaquin Valley of California (USA) are attributed to predominantly connate water composition and large-scale recharge from the adjacent Sierra Nevada. However, in smaller areas, stratigraphy and faulting play an important role in controlling TDS. Here, the relationship of stratigraphy and structure to TDS concentration was examined at Poso Creek Oil Field, Kern County, California. The TDS model was constructed using produced water TDS samples and borehole geophysics. The model was used to predict TDS concentration at discrete locations in 3D space and used a Gaussian process to interpolate TDS over a volume. In the overlying aquifer, TDS is typically <1,000 mg/L and increases with depth to ~1,200–3,500 mg/L in the hydrocarbon zone below the Macoma claystone—a regionally extensive, fine-grained unit—and reaches ~7,000 mg/L in isolated places. The Macoma claystone creates a vertical TDS gradient in the west where it is thickest, but control decreases to the east where it pinches out and allows freshwater recharge. Previously mapped normal faults were found to exhibit inconsistent control on TDS. In one case, high-density faulting appears to prevent recharge from flushing higher-TDS connate water. Elsewhere, the high-throw segments of a normal fault exhibit variable behavior, in places blocking lower-TDS recharge and in other cases allowing flushing. Importantly, faults apparently have differential control on oil and groundwater. [ABSTRACT FROM AUTHOR]

Sulphate-reducing bacteria (SRB) cause fouling, souring, corrosion and produce H2S during oil and gas production. Produced water obtained from Periquito (PQO) and Galo de Campina (GC) onshore oilfields in Brazil was investigated for SRB. Produced water with Postgate B, Postgate C and Baars media was incubated anaerobically for 20 days. DNA was extracted, 16S rDNA PCR amplified and fragments were sequenced using Illumina TruSeq. 4.2 million sequence reads were analysed and deposited at NCBI SAR accession number SRP149784. No significant differences in microbial community composition could be attributed to the different media but significant differences in the SRB were observed between the two oil fields. The dominant bacterial orders detected from both oilfields were Desulfovibrionales, Pseudomonadales and Enterobacteriales. The genus Pseudomonas was found predominantly in the GC oilfield and Pleomorphominas and Shewanella were features of the PQO oilfield. 11% and 7.6% of the sequences at GC and PQO were not classified at the genus level but could be partially identified at the order level. Relative abundances changed for Desulfovibrio from 29.8% at PQO to 16.1% at GC. Clostridium varied from 2.8% at PQO and 2.4% at GC. These data provide the first description of SRB from onshore produced water in Brazil and reinforce the importance of Desulfovibrionales, Pseudomonadales, and Enterobacteriales in produced water globally. Identifying potentially harmful microbes is an important first step in developing microbial solutions that prevent their proliferation. [ABSTRACT FROM AUTHOR]

Water production management from oil and gas fields is a big challenge for petroleum industry. Re-injection and disposal of produced water into subterranean formations/oil reservoirs is considered as an environmentally-friendly solution for managing massive water production in petroleum industry. Formation damage resulted from plugging by dispersed particles in the injected water is one of the main concerns in waterflood/disposal projects that causes rapid permeability impairment. Main mechanisms for permeability decline due to injection of low-quality water are deep filtration of dispersed particles into the porous rocks and external filter cake formation on the injection surface. In this article, an empirical correlation is developed for prediction of transition time from deep bed filtration to external cake formation based on available experimental data points from the literature. The proposed correlation includes measurable parameters such as solid particle size to pore size ratio (jamming ratio) and injection concentration of suspended particles which was ignored in previous studies. The proposed correlation is evaluated with water injection data of 15 wells with good agreement. The developed correlation can be used for design and planning of operations with solid in liquid dispersion including drilling fluid, low-quality water flooding, and waste water disposal into subterranean formations. [ABSTRACT FROM AUTHOR]

Summary: Carbon steel pipelines, a means for crude oil transportation, occasionally experience highly localized perforation caused by microorganisms. While microorganisms grown in laboratory culture tend to corrode steel specimens unevenly, they rarely inflict a corrosion morphology consistent with that of pipelines, where centimetre‐sized corrosion features are randomly distributed within vast stretches of otherwise pristine metal surface. In this study, we observed that corrosion inhibitors (CIs), widely used for the control of acid gas (H2S, CO2) corrosion in oil fields, also affect microbial growth and activity. Inhibited carbon steel resisted biofilm formation and underwent negligible corrosion (< 0.002 mm Fe0 year−1), despite 15 months of exposure to oil field waters harbouring a diverse microbiome. In contrast, physical scavenging of CI in these waters led to severe and highly localized corrosion (up to 0.93 mm Fe0 year−1) underneath biofilms dominated by methanogenic archaea and sulfate‐reducing bacteria. A sharp decline in CI concentration, as well as its active components, quaternary ammonium compounds (QACs), correlated with microbial sulfidogenesis. CIs are ubiquitously present in oil field waters and play an underappreciated role in microbial corrosion mitigation. Physical and biological scavenging of CIs may create local differences in steel inhibition effectiveness and thus result in highly localized corrosion. [ABSTRACT FROM AUTHOR]

Produced water (PW) exploited from the reservoir alongside oil often contains heavy metals and other impurities that are harmful to man and the environment. Most of the PW treatment technologies that have been in use for years have been reported to be ineffective in reducing some of the impurities and metal concentrations to allowable disposal levels. This study evaluated the effectiveness of four local materials combined for treating PW from Niger Delta oil fields. Orange peels (I), banana peels (II), sponge gourd (Luffa cylindrica) (III) and palm kernel fibers (IV) were washed with distilled water, sun-dried (24 hours) and oven-dried at 105 ± 5°C (3 hours, I and II), 150°C (30 minutes, III) and 80°C (3 hours, IV). They were ground into powder, sieved (150 microns, Group A) and (300 mcicrons, Group B), washed with 0.4 mol/L HNO3, filtered and rinsed with distilled water. Samples of PW were obtained from fields R, X, and Y in the Niger Delta and analyzed for heavy metals using an Atomic Absorption Spectrophotometer (AAS). The PW samples were treated with the bio-adsorbents sequentially in the adsorption column for over 7 hours. Langmuir and Freundlich models were used to evaluate the samples and the Data was analyzed based on regression method. The 150 micron size of sample R, lead (Pb), cadmium (Cd), copper (Cu), and chromium (Cr) were completely (100%) adsorbed from the PW after 8 hours of treatment while other metals (Ni, Fe, Mg, Zn, Mn, Ca, Ar, B, Sn, Ba) were found to be 86.11%, 90.76%, 39.25%, 94.40%, 43.55%, 99.26%, 54.62%, 44.53%, 84.52%, and 47.37%, respectively. while the reduction in 300 micron size were 23.48% for Pb, 80.20% for Ni, 71.42% for Cd, 19.73%, for Cu. 43.65% for Fe, 34.79% for Mg, 12.67% for Cr, 88.8% for Zn, 35.48% for Mn, 98.95% for Ca, 23.01% for Ar, 44.52% for B, 14.83% for Sn and 23.68% for Ba, respectively. The finer adsorbent with large surface area was more effective. Similar results were obtained for PW samples from the other fields. Sequential mixture of the bio-adsorbents selected proved valuable in the treatment of contaminants in PW from Niger Delta oil fields. [ABSTRACT FROM AUTHOR]

A marine Streptomyces sp., which has an inhibitory effect on sulfate-reducing bacteria (SRB), was selected to study inhibitory effect and mechanism of X65 steel on SRB corrosion in oilfield produced water. Streptomyces and SRB had a competitive growth relationship. The Streptomyces metabolites affected the number and activity of SRB and had good corrosion inhibiting properties. The formation and development of SRB biofilm was inhibited. Mixed bacteria inhibited anodic dissolution of X65 steel and slowed down the electrochemical reaction rate. The film layer on the sample was denser, and the average and localized corrosion rates caused by SRB were significantly suppressed. • Streptomyces sp. and its metabolites effectively inhibited SRB-induced corrosion. • Inhibition mechanism was discussed in terms of competitive growth, metabolite and biofilm. • Green protection to inhibit MIC by "bacteriostasis with bacteria" was proposed. • Broadening application field of marine Streptomyces sp. and enriching the theory of MIC. [ABSTRACT FROM AUTHOR]

Problems related with refining of water-in-oil (W/O) petroleum field emulsions and also produced water evacuation limitation have created a need for more research in practical demulsification. Among the most commonly used demulsification techniques (e.g., chemical, biological, membrane, electrical, and microwave irradiation) used in the separation of water from crude oil, biological demulsification with bacterial demulsifiers or biodemulsifiers is a new biocompatible method with relatively efficient performance. The main goal of this study was to obtain demulsifying bacteria. Following a multi-step screening and enrichment method and with the aid of biochemical and physiological tests and 16S rDNA sequencing analysis a demulsifying bacterium, Delftia sp. strain HS3 (accession number: MF139710) was isolated from crude oil samples of an oil refinery located in southwest Iran. The presence of hydrocarbon material in growth medium was found to be unnecessary for production of the biodemulsifier. The demulsifying ability of the isolated bacterium was investigated through demulsification tests on W/O model emulsions. The demulsifying activity of the produced biodemulsifier was thermally stable and it increased with bacterial culture age. This bacterium has potential as a biodemulsifier producer for future studies and industrial demulsification applications. [ABSTRACT FROM AUTHOR]

This study analyzes the influence of the corrosion inhibitor films "Olazol T2P," "Olazol 26501," "Telaz," "Inkorgaz-21T," and "IKB2-2" on corrosion damage of 20-KSH steel in the moist atmosphere of the simulated solution of reservoir water of oil fields. It was established that the preliminary application of the corrosion inhibitor films "Olazol T2P," "Olazol 26501," and "Telaz" to the steel surface effectively increased the corrosion resistance of steel in the moist atmosphere of the simulated solution. The application of the corrosion inhibitor films ensures high corrosion resistance and significantly reduces the risks of corrosion damage of natural gas preparation equipment. [ABSTRACT FROM AUTHOR]

Water plugging is an important objective in oil field processes owing to the increase in the water content of the produced fluids. Hence, a type active crude oil for water plugging in oil fields was prepared by optimizing the emulsifier and crude oil concentrations. The emulsion stability, rheological properties, and plugging behavior of the active crude oil were investigated. Results showed that the emulsion stability of the active crude oil was affected not only by the composition of the crude oil but also by the hydrophibicity of the emulsifier. Liaohe oil with high contents of asphaltene and resin showed better viscosity–temperature characteristics than the other crude oils and was used to prepare the active crude oil with high viscosity. Sorbitan monooleate (Span80) with long unsaturated alkyl chains showed better emulsion stability than other emulsifiers; the active crude oil emulsion with Span 80 as the emulsifier showed excellent viscosity–temperature properties. The active crude oil formed with Liaohe oil and Span 80 showed better plugging performance for cores with high permeability and for those saturated with water, and the plugging rate was over 99%. The microvisual model clearly showed the emulsification and plugging behavior. Moreover, the oil recovery increased obviously after active crude oil injection into the heterogeneous core. [ABSTRACT FROM AUTHOR]

Elevated concentrations of the radium isotopes 224,226,228Ra exist in the scale and produced water in oil exploration. The activity concentration of 226Ra was calculated from 186.2 keV peak with no usual spectral interference of 185.7 from 235U. The activity concentration of 228Ra was calculated from its first daughter product 228Ac using the 911.2 keV gamma rays since it is a pure beta emitter. The activity concentration of 224Ra was calculated from 212Pb using the 238.6 keV gamma-ray and the secular equilibrium equation with 228Ra. The IAEA 448 (oil contaminated field soil) reference material was used as a quality control for 226,228Ra and but was unreliable for 224Ra using 212Pb. [ABSTRACT FROM AUTHOR]

The Oligocene–Miocene Asmari Formation is well known as a major hydrocarbon reservoir in southwestern Iran. To study the microfacies and sedimentary environment of Asmari Formation in the Zagros basin (south-west Iran), No. 6 well and No. 11 well sections in Zeloi oil field were selected. 500 thin sections were studied for petrographic and facies analysis. Based on petrographic and sedimentology analysis of the Asmari Formation in these sections, 13 carbonate microfacies and 1 petrofacies can be identified into three main depositional environments consisting of: outer ramp, middle ramp and inner ramp. The outer ramp environment is characterized by the presence of abundant planktonic foraminifera and echinoid fragments. The middle ramp environment is represented by the presence of echinoids and planktonic foraminifera, red algae and perforate foraminifers. In the inner ramp, the most allochems are ostracoda, imperforate and perforate benthic foraminifera, algae ball, peloid and oncoid. [ABSTRACT FROM AUTHOR]

Bacteria from the genus Geobacillus are generally obligately thermophilic, with a unique bioenergy production capacity and unique enzymes. Geobacillus species were isolated primarily from hot springs, oilfields, and associated soils. They often exhibit unique survival patterns in these extreme oligotrophic environments. With the development of the microbial resources found in oilfields, Geobacillus spp. have been proven as valuable bacteria in many reports related to oilfields. After the isolation of Geobacillus by culture methods, more evidence was found that they possess the abilities of hydrocarbon utilization and bioemulsifier production. This paper mainly summarizes some characteristics of the Geobacillus species found in the oilfield environment, focusing on the inference and analysis of hydrocarbon degradation and bioemulsifier synthesis based on existing research, which may reveal their potential value in microbial enhanced oil recovery. It also provides references for understanding microbes in extreme environments. [ABSTRACT FROM AUTHOR]

In order to reduce the cost of phytoremediators selection in phytoremediation on petroleum-contaminated soils, long-term experiments and in-situ trials included, an evaluation system for plant selection in phytroremediaiton was conducted in accordance with two case study, Changning shale gas field and Liaohe oil field. The evaluation system was constructed with two multi-objective decision-making methods, analytic hierarchy process (AHP) and technique for order of preference by similarity to ideal solution (TOPSIS), combined with triangular fuzzy numbers (TFNs). The comprehensive evaluation system was involved with three criteria and nine indexes. The calculated weights indicated that moisture was the most influential factor in the plants selection with the highest weight in both Changning shale gas field and Liaohe oil field. A total of 23 plants from these two study areas were used as alternative plants for phytoremediation and it suggested that Testuca arundinacea might be a suitable plant for the phytoremediation process after determination. Results of sensitivity analysis confirmed that the combination of the fuzzy AHP and TOPSIS in these process was reasonable and practicable. The successful application of fuzzy AHP and TOPSIS, to plant selection for the phytoremediation of petroleum-contaminated soils was also highlighted. The usefulness of the combined application of these two methodologies for decision-makers is anticipated. Such a combination is a convenient and effective approach to the selection of suitable plants for the phytoremediation of petroleum-contaminated soils and it can provide scientific and technological support for decision-makers during the supervision of petroleum-contaminated sites. [ABSTRACT FROM AUTHOR]

The Patos-Marinza oil field in Central Albania (40.71° N,19.61° E), operated since 1939, is one of the largest onshore fields in Europe. More than 7 millions oil barrels are extracted per year from the Messinian sandstone formations of the Durres Basin in the Albanian Peri-Adriatic Depression by the Bankers company operating the field since 2004. In the region, the background seismicity culminated in December 2016, when a shallow seismic swarm developed in the oil field, damaging houses and triggering the opening of a public inquiry. However, because of the lack of a dense local seismic array and incompleteness of historical catalogues for such moderate events, understanding whether this seismicity could be induced by the extraction/injection activities is an arduous task. In this study, we take advantage of the new Sentinel-1 radar images acquired every 6 to 12 days over Albania to measure the surface displacement in the Myzeqeja plain and in the Patos-Marinza oil field in particular. Images from two ascending and descending tracks covering the area are processed through a radar interferometry (InSAR) time-series analysis over the 2014 to 2018 time-span, providing consistent average Line-Of-Sight velocity maps and displacement time-series. The regional deformation field exhibits a slow subsidence of the entire sedimentary basin relative to the highlands (at rates of 2.5 mm/yr), that we interpret as a combination of natural and man-induced compaction. This broad picture is complicated by a very strong local subsidence signal with rates as high as 15 mm/yr that spatially correlates with the Patos-Marinza oil field and is maximal in the zone holding most of the operating horizontal wells, where Enhanced Oil Recovery techniques are used. The striking spatial correlation between the maximum subsidence area and the active wells, as seen from optical images, argues in favor of an oil-extraction induced surface deformation. The observed surface deformation is well reproduced by elastic models mimicking the basin and reservoir compaction using planar crack dislocations. Such modeling provides a first-order estimation of the volumetric deflation rate in the oil reservoir (~ 0.2 Mm³/yr). This strong subsidence signal, together with the increase of the background seismicity since the oil field reactivation, are evidences of significant man-induced stress changes in the basin that should be further monitored and taken into account for seismic hazard assessment. [ABSTRACT FROM AUTHOR]

Tahe oil field is the first marine origin oil field in China, with proven reserves of 500 million tons. Given the important role of the paleogeomorphology in controlling the formation and distribution of karst reservoirs, this paper restored the pre-Carboniferous paleokarst landform in the major blocks of the Tahe oil field, via the paleogeomorphic genesis assembly method. First, four types of secondary landform units (karst platform, karst gentle slope, karst steep slope, and karst intermountain basin) were defined. Next, landform identification factors were added to these four types, to further divide the paleokarst landform into ten tertiary landform units. This enabled a more precise identification of the paleogeomorphic landforms. The karst development and the properties of hydrocarbon reservoirs in micro-geomorphic units were assessed. In addition, the relationship between petroleum production and geomorphology was analysed to robustly predict karst reservoirs in the Tahe oil field. The results show that karst develops differently according to the ancient landform units it developed from and that the current karst function is highly dependent on the precursor ancient landform. In addition, the morphology of the ancient landform significantly controls hydrocarbon accumulation, with oil and gas production being highly associated with the degree of karst development in each landscape unit. The research results indicate that the position of the slope in the karst hill and residual peak is favorable for future oil and gas exploration. [ABSTRACT FROM AUTHOR]

The study focuses on measuring the values of 238U, 232Th and 40K natural radionuclides in soil samples in Badra oil field area (Iraq). Also, the radiological risk data were calculated for all samples in this study. The technique used in this study was gamma-ray spectrometry with NaI(Tl) detector. The averages of specific activity are: 24.7 Bq/kg for 238U, 13.6 Bq/kg for 232Th, and 538.9 Bq/kg for 40K. Besides, the estimations of radiological effects like the radium equivalent (Raeq), the absorbed dose rate (Dr), external hazard index (Hex), internal hazard index (Hin), representative gamma hazard index (Iγ) and the total annual effective dose equivalent (AEDE) are 85.5 Bq/kg, 42.1 nGy/h, 0.23, 0.30, 0.66 and 0.26 mSv/y respectively. When comparing the results in the study area with the world mean values specified by the UNSCEAR, OCDE and ICRP, the study terminates that the limits of health risk are safe and may not menace the workers at these locations due to these radionuclide limits. The values were subjected to GIS environment under the WGS1984 coordinate system for the sake of results’ coordination, and processed in Inverse Distance Weighted interpolation as the best processing. [ABSTRACT FROM AUTHOR]

Produced water (PW), water extracted along with oil, can cause important environmental challenges due to its high volume and salinity and is considered a key factor in the economic exploitation of oil fields. Therefore, making use of a cost-effective integrated system of wastewater treatment is a fundamental requirement in oil and gas industries. In this paper, the integrated PW treatment system is presented using superstructure-based mathematical optimisation methodology which is aimed at minimising the total annual cost. Two distinct scenarios of injection and reuse in industrial scale are considered to propose an efficient and optimal integrated system. The results show that, despite the emergence of new technologies, the traditional ones such as gravity separation, hydrocyclone, and media filters, with a cost of $0.509 per cubic meter, are selected as the optimum solution for treating PW for injection purpose. Because of the poor quality of PW in Iran, reuse options are limited, and the efficient available technologies are few. Mechanical Vapor Compression (MVC) and Multi Effective Desalination (MED) technologies are investigated as two desalination options. According to the findings, a treatment system composed of MVC with appropriate pretreatment is capable of recovering 50% of the PW, which is the optimal water recycling option with a total treatment cost of 3.808 $/m3. In cases of increasing the volume of PW with time, it is concluded that utilising advanced treatment system to recover a part of PW, decreases the annual cost up to 20% in comparison with the case which increases the PW injection capacity. This can be considered as a more viable management strategy for PW management in future. [ABSTRACT FROM AUTHOR]

• An integrated system for produced water treatment in onshore oilfields is presented. • A superstructure-based optimisation model is developed for integrated system. • Performance of MED and MVC for hypersaline produced water are investigated. • Injection and internal reuse of produced water are considered as two scenarios. Produced water (PW), water extracted along with oil, can cause important environmental challenges due to its high volume and salinity and is considered a key factor in the economic exploitation of oil fields. Therefore, making use of a cost-effective integrated system of wastewater treatment is a fundamental requirement in oil and gas industries. In this paper, the integrated PW treatment system is presented using superstructure-based mathematical optimisation methodology which is aimed at minimising the total annual cost. Two distinct scenarios of injection and reuse in industrial scale are considered to propose an efficient and optimal integrated system. The results show that, despite the emergence of new technologies, the traditional ones such as gravity separation, hydrocyclone, and media filters, with a cost of $0.509 per cubic meter, are selected as the optimum solution for treating PW for injection purpose. Because of the poor quality of PW in Iran, reuse options are limited, and the efficient available technologies are few. Mechanical Vapor Compression (MVC) and Multi Effective Desalination (MED) technologies are investigated as two desalination options. According to the findings, a treatment system composed of MVC with appropriate pretreatment is capable of recovering 50% of the PW, which is the optimal water recycling option with a total treatment cost of 3.808 $/m3. In cases of increasing the volume of PW with time, it is concluded that utilising advanced treatment system to recover a part of PW, decreases the annual cost up to 20% in comparison with the case which increases the PW injection capacity. This can be considered as a more viable management strategy for PW management in future. [ABSTRACT FROM AUTHOR]

• We looked into the potential applications of hydrate-based desalination(HBD). • HBD process treats produced water with a concentration of 2.8 wt%. • CO 2 + C 3 H 8 as guest gas produced a water recovery of 67.3%. • The desalination efficiency is strongly dependent on the ionic radii and the strength of the ionic charge. Recent years have seen increased interest in gas hydrate production as a viable saline water desalination technique. Produced water is the liquid that is extracted from oil and gas fields and is typically salty. The management of produced water is a significant aspect of the petroleum industry because of its potential to serve as a source of fresh water for oil-producing nations with limited access to clean water, growing environmental concerns, and the strict laws governing the discharge of produced water into the environment. In this study, the effect of mixed gas (CO 2 + C 3 H 8 (70:30)) hydrate formation in treating produced water and kinetic studies on induction time, moles of gas consumed, rate, water recovery, and water-to-hydrate conversion were experimentally investigated. An aqueous solution with the same ion concentrations was prepared and experiments were performed at 275.15 K/277.15 K, 2.0 MPa, and 450 rpm. The findings unveiled that with an increase in salinity, the water recovery decreased showing the hindering effect of salts on mixed hydrate formation by reducing the solubility of mixed gas due to the strong electrostatic force of attraction between salt ions and water. A maximum of 67.3% water recovery was observed in 2.8 wt% produced water solution at 275.15 K, 2.0 MPa, and 450 rpm. Furthermore, the induction time increased by 52.64% in treating 2.8 wt% and a decrease in moles of gas consumed, water recovery, and water-to-hydrate conversion by 6.99%, 2.08%, and 9.69% compared to the deionized water system at 275.15 K. A removal efficiency of 47%-63% is achieved by using CO 2 + C 3 H 8 and the sequence of metal cation removal is in the order K+ > Na+ > Mg2+ > Ca2+ and anions SO 4 2− > Cl− at 275.15 K. The results also showed that with a rise in the experimental temperature to 277.15 K the removal efficiency increased though the amount of hydrate formed is less. This study illustrates that the formation of mixed gas (CO 2 + C 3 H 8) hydrate can be used for treating produced water based on the water recovery, removal efficiency, electrical conductivity, and total dissolved solids results with lower energy consumption. [ABSTRACT FROM AUTHOR]

This paper focuses on the layout design of subsea oil gathering-transportation system in deep water oil field. In such a system, subsea manifolds are applied to gather and transport the produced fluids from subsea wells to floating processing terminals. A mixed integer nonlinear programming (MINLP) model is proposed, constrained by a series of operation and production requirements, aiming to minimize the total layout cost. Through the model, the pipe line network topology structure which reflects the allocations among the subsea wells, manifolds and processing terminals, the routes of pipes, as well as the size of the facilities could all be figured out. Two key contributions are made through this work. First, avoiding pipe intersections and subsea obstacles are integrated simultaneously, making the proposed model closer to practical situations. Second, a decomposition strategy based on Delaunay triangulation and gradient descent is constructed, achieving high quality initial solution and stable iteration process. The results of case studies indicate the validity, feasibility and stability of the proposed model and the solution method. Besides, the effect of manifold numbers on the layout optimization result is analyzed through the model, indicating its flexibility in the layout design analysis. • A MINLP model is built to optimize subsea oil gathering-transportation system layout. • Avoiding pipe intersections and subsea obstacles are integrated simultaneously. • Solution strategy combined Delaunay triangulation and gradient descent is developed. • Case studies indicate the model's feasibility, stability and flexibility. • The results considering different manifold numbers are compared and analyzed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biogenic silica wastes modified for TOC removal and treatment of oilfield-produced water; • The adsorbent showed a large surface area of over 1000 m2/g; • The adsorbent was highly recyclable, being reused in up to 15 cycles; • CAM adsorbent removed 73 % of TOC from real produced water in 150 min. The escalating fuel demand generates significant volumes of oilfield-produced water containing complex environmental pollutants such as phenol. This study proposes a purification method for converting activated carbon (CAM), obtained at zero cost as a by-product of biogenic silica production, into an effective adsorbent. The activated carbon was characterized extensively for its morphological, structural, and chemical properties, revealing a substantial surface area exceeding 1000 m2/g. The adsorption process for phenol removal was investigated through kinetics, isotherms, and thermodynamic analyses. Kinetic data analysis favored the PSO models within 150 min, while equilibrium studies showed the best fit for the Sips and Liu models. CAM achieved an adsorption capacity of 23.9 mg g−1 for phenol removal at pH 6, the typical pH of produced water. The adsorption process was found to be exothermic and spontaneous. The produced adsorbent demonstrated high recyclability, with up to 15 reuse cycles achievable through regeneration via thermal desorption at 180 °C. Furthermore, CAM removed 73 % of total organic carbon from real produced water within 150 min. Thus, using activated carbon intrinsically carbonized during silica production is an economically viable and attractive solution for treating phenol-contaminated oilfield-produced water. [ABSTRACT FROM AUTHOR]

• Recycling produced water as subsequent preparation of fracturing gels after shielding residual boron. • The produced water can be directly prepare subsequent fracturing gels without extra filter of boron & complexes. • Directly shielding technology shows good costs and efficiency compared with conventional boron treatments. • The HPG system containing boron & complexes does not affect subsequent rheological property of fracturing gel. • Mannitol is a cost-effective and readily biodegradable material. Large volumes of fracturing flowback fluids are generated as produced water (PW) during oil & gas extraction. There is a method that uses such produced water as a suitable source of fracturing water, recycling it into subsequent fracturing gels. Not only does it reduce processing costs and environmental pollution, but it also effectively alleviates the problem of oilfield water shortage. However, the existence of residual boron in PW is a crucial obstacle to reutilization because it prematurely crosslinks hydroxypropyl guar (HPG) that affects pumping and fracking. So it is necessary to eliminate the adverse effect of residual boron in terms of recycling PW. Fortunately, boric acid easily reacts with polyols by bonding with other active cis-hydroxyl groups to form complexes, preventing residual boron from prematurely crosslinking with HPG. This study demonstrated the feasibility of shielding residual boron crosslinker in PW by a series of simulated crosslink systems. Results indicate that mannitol has a high complexation capacity for boron since it forms stable 5-member ring complexes by bonding with borate ion. When the mole ratio of ligand to boric acid exceeds 2.5 and the pH value is around 10.5, the shielding efficiency of mannitol to boron reaches 95%. The excessive amounts of ligands completely shield the boron and prevent its continuous crosslinking with HPG. The fracturing gels prepared by PW no longer show the premature crosslinking phenomenon after the shielding agent is added, and its rheological properties loading the new crosslinker are similar to the system which is prepared with deionized water. These results indicate that mannitol can effectively shield the residual boron crosslinker, removing the adverse effects of premature crosslinking with HPG base fluid. This has formed stable complexes, which still exist in the HPG base fluid system and do not affect the rheological properties of the subsequent fracturing gels. Compared with conventional boron treatment technologies, this treatment system also directly prepares the subsequent fracturing gels without the additional steps of filtering boron-complexes. Therefore, there are many significant advantages in these operational steps over traditional boron removal methods from the perspective of efficiency and cost-effectiveness. [ABSTRACT FROM AUTHOR]

In Tahe oilfield of Xinjiang, China, the carbonate reservoir displays poor porosity and permeability in its matrix, while the fracture-cave formation is distributed in a random, discreet and discontinuous way. As the oil recovery with water injection mechanism shows, the water injection curve of the carbonate reservoir differs from that of the sandstone reservoir. For discontinuous carbonate reservoirs, the reservoir type can be determined from the shape of the water injection curve. For karst-cave reservoirs with high permeability, on the other hand, the new theoretical model of the water injection process can be adopted to calculate the volume of a single cave or a multiple of caves, crude oil, and formation water. The calculated results agree well with the practical results. [ABSTRACT FROM AUTHOR]

Recent development in oil field tracer technologies has been focused on implementations that increase oil recovery through optimized algorithms for production, aided by the addition of high fidelity interwell tracer data that improve reservoir history match. Prerequisites for successful tracer campaigns in oil reservoirs at a large scale not only include low-cost tracer materials with a rich palette of uniquely identifiable tracers, but also high sensitivity, easy-to-use trace-level detection and analysis methodologies. A fully automated in-line separation and detection protocol can simultaneously address challenges in throughput (speed and efficiencies) and accuracy (minimization of error-prone steps) of multi-tracer detection. Our previously reported tracer materials consist of barcoded variants of the dipicolinic acid (DPA) molecules that sensitize the emission of lanthanide ions. We have capitalized on the time-gated optical luminescence detectability of this sensitizer-lanthanide ion complex to reject background oil fluorescence, achieving high detection sensitivity in particularly complex oil field produced brine matrix. However, automation of the detection and analysis process has been hindered by opposing requirements in the integration of chromatography instrumentation (separation resolution) with in-line mixing (dispersion due to increase in residence time), and high sensitivity spectrofluorimetry (long integration time). We overcome this major barrier to implementing an in-line detection design under flow conditions by utilizing a microfluidic mixing chip which offers a high degree of mixing in a very short fluidic path length for the in-flow chelation of lanthanide ion to the chromatographically resolved tracer variants, and a flow-cell fluorescence detector at the output of the high-performance liquid chromatography (HPLC). In this study, we demonstrated the rapid in-line detection of a mixture of three different DPA-based barcoded tracers at ultra-trace level. An automated solid phase extraction (SPE) pre-concentration stage is added to the input of the HPLC, further lowering the detection limit down to a level of 100 pM (pico molar) of tracer molecules. As developed, the complete automated system offers unprecedented sensitivity of detection and accelerated oil field tracer analysis that approaches "near real-time" speed. • A fully automated in-line separation and detection protocol for multi-tracer detection. • Time-gated optical detection of the sensitizer-lanthanide ion complex. • Eliminating background oil fluorescence achieves high detection sensitivity. • Conducted under flow conditions by utilizing a microfluidic mixing chip for the efficient tracer lanthanide chelation. • Unprecedented sensitivity of detection and accelerated oil field tracer analysis. [ABSTRACT FROM AUTHOR]

In this work, we approach the subject of the transport of crude oil - formation water mixtures in the oil fields. For the study of the influence of the formation water over the hydraulic performances of the transport pipelines, we present the transport simulation on 3 pipelines of different diameters with different formation water cut. For the simulation, we used a numeric modeling software, inspired from that designed by ASPENTECH. The simulation results are presented synthetically as tables and suggestive charts. [ABSTRACT FROM AUTHOR]