Search

Copyright of Oilfield Chemistry is the property of Sichuan University, Oilfield Chemistry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As the information age progresses and oilfield production deepens, information technology plays an increasingly pivotal role in oilfield production, scientific research, and management. Data quality and integrity have become key issues in both research and production. This study analyzes the architecture of data quality control methods based on the technical system of the OSDU (Open Subsurface Data Universe) sharing center. A virtual data layer (VDB) is introduced, and the overall architecture of the exploration and development data exchange management platform is constructed through collaborative technology. Employing a systematic design concept, all applications within the data exchange management architecture are organically combined, forming an integrated and cohesive design and development strategy. This research presents a novel approach where the system application is distinctly separated from the database management. This strategy effectively resolves the challenges associated with managing metadata in oilfield exploration. By designing the database and coding specifications, the development and deployment of the system are completed efficiently. The implemented system offers comprehensive functionalities to all oilfield levels, including data storage, auditing, querying, statistical analysis, and data exchange management. It facilitates the seamless exchange of diverse exploration and development data, ensuring scientific data management and establishing a foundation for shared scientific data. This enhances service quality and the level of exploration and development in the field. This paper focuses on the design and development of a data exchange management platform for oilfield exploration and development, using the oil and gas industry as a case study. The analysis of industry demands and technology supply within this context is crucial for advancing the exploration and development capabilities in oilfields. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Bioprocess Engineering is the property of Chinese Journal of Bioprocess Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Frequent water injection and oil extraction can potentially lead to changes in reservoir pressure, burst or collapse of casings, and corresponding variations on the ground surface. Attention should be focused on developing the strategies to monitor and mitigate the adverse consequences of oilfield operations. Here, the distributed scatterer InSAR (DS-InSAR) technique is applied to estimate the surface deformation of Daqing oil field with the surveillance period from 2015 to 2019. Furthermore, Bayesian method with three models, including Mogi, prolate spheroid, and Okada, are implemented to obtain parameters related to underground cavities, using cumulative deformation recorded between June and December 2015 and May and December 2016 as input. Inversion validation measurements were carried out by comparing the results with field data in the area of interest. Our findings demonstrate that, in comparison to other models, the prolate spheroid could recover both reservoir pressure and surface deformation, offering compelling evidence in favor of mitigating shear failure-related issues. A dual-source prolate spheroid model is also used to simulate large-scale deformation on the surface of oilfield. Its characteristics are nearly in line with variations in reservoir pressure and casing depth, which may minimize the negative consequences of casing failures and guarantee the stability of oil production.

The production for crude oil usually leads to contamination of the soil with trace metals and organic contaminants from spilled petroleum. Organic contaminants were generally paid more attention than trace metals in the oilfield pollution. Many studies have investigated the impacts of some petroleum hydrocarbon pollutants, however, the impacts and risk assessment of trace metals remain largely unexplored. Moreover, under some circumstances, the risks associated with trace metals are not necessarily lower than those associated with organic contaminants. This study aimed to investigate methods to evaluate the possible risks associated with 11 trace metals (Ti, Ba, Sr, Rb, V, Li, Mo, Co, Cs, Bi, and Tl) in soil and biota samples from the Shengli Oilfield using ICP-MS. The results showed that 11 trace metals in the surface soils exceeded the local background levels. The geo-accumulation index (Igeo) indicated that the soils had light-moderate to moderate contamination levels, with higher Igeo value of Ba, V, Li, Mo, Co, and Cs. The individual potential ecological risk indices ( E r i ) demonstrated moderate Bi and Tl pollution in soils. Comparatively, the E r i is recommended for the risk assessment of trace metals on the ecosystem around the oilfield area. Mo, Bi, and Sr easily accumulate in plants, as reflected by their bioaccumulation factor. Ti, Ba, V, Li, Co, Cs, Bi, and Tl exhibited considerable biomagnification, particularly in birds. In this study, trace metals showed considerable bioaccumulation and biomagnification, and the risks of these trace metals on the ecosystem around oilfield production area need more attention. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to assess differential vertical and horizontal deformations for the offshore Kashagan oilfield located in the Northern Caspian Sea. Sentinel-1 (SNT1) and COSMO-SkyMed (CSK) synthetic-aperture radar (SAR) images (9 January 2018–6 April 2022) were processed using persistent scatterer interferometric SAR (PS-InSAR) technique with further 2D decomposition of line-of-sight (LOS) measurements to differential vertical and horizontal deformations. Differential vertical deformation velocity was observed to be between −4 mm/y and 4 mm/y, whereas horizontal was between −4 mm/y and 5 mm/y during 2018–2022. However, it was possible to observe the spatial deformation patterns with the subsidence hotspots reaching differential cumulative vertical displacement of −20 mm from both satellite missions. PS-InSAR differential vertical deformation measurements derived from SNT1 and CSK satellite images showed identical spatial patterns with moderate agreement, whereas poor agreement was observed for differential horizontal deformations. The differential vertical deformation hotspots were observed for the oilfield areas installed on piles with obviously higher vulnerability to dynamic movements. Through this study, based on the interferometric measurements, marine geotechnical expert feedback, and no reported deformation-related incidents since 2013, it was possible to conclude that the Kashagan oilfield had not been impacted by significant differential vertical and horizontal deformations on the oilfield. However, since long-term GPS measurements were not accessible from the oilfield to be used as the reference for PS-InSAR measurements, we were not able to judge the long-term displacements of the entire oilfield or possible oscillations, even though it is built on the artificial island. Considering the broad range of PS-InSAR measurements using time-series radar images, the interferometric measurements could play a significant role in the prioritization of insitu risk assessment activities, operational cost reduction, strengthening of safety factors, and planning of further targeted insitu measurements. [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]

Oilfield-produced water treatment using raw Kapok fiber (RKF) and a modified surface of Kapok fiber followed by an ultrafiltration membrane was conducted to reduce total dissolved solids (TDS), phenol, and barium. Variables considered in the experiment were contact times (30, 60, 90 min.), the flow rate of samples (5, 6, and 7 L/min), and trans-membrane pressure of ultrafiltration membrane (0.25, 0.35, and 0.50 bar). Raw Kapok fiber and modified surface Kapok fiber were used to investigate the effect of Kapok fiber on total dissolved solids, phenol, and barium removals from produced water. The results showed that raw KF decreased the TDS, phenol, and barium by 51.81%, 62.63%, and 54.20%, respectively. Treatment of raw Kapok fiber column filtrate using ultrafiltration membranes (UF) showed the removal of TDS, barium, and phenol achieved 73.15%, 42.44%, and 79.45%, respectively, at a flow rate of 5 L/min, TMP of 0.25 bar, and contact time of 90 min. Modifying the Kapok fiber surface using sodium hydroxide solution (5 wt%) and hot water (98.5 °C) reduced the TDS, phenol, and barium to 57.32%, 65.83%, and 79.08%, respectively. Further, at the same operating condition, the modified surface of Kapok fiber followed by UF decreased 94.31% TDS, 84.20% phenol, and 56.23% barium, respectively. The results show that modification of the Kapok fiber surface followed by UF can be used to remove the TDS, phenol, and barium from produced water. [ABSTRACT FROM AUTHOR]

Integration of source, grid, load, and storage is an important measure for energy transformation. However, at present, the oilfield industry lacks mature models and related technologies. Therefore, an oilfield intelligent energy system integrating source, power grid, load, and storage is proposed in this paper. In view of the poor oilfield data quality, abnormal/missing data diagnosis and repair methods are proposed to improve the information accuracy of the intelligent cloud management center. The improved photovoltaic prediction method of conditional generation countermeasure network (CGAN), PV-VSG control of additional control, and flexible load control are put forward to upgrade the intelligent deployment system. The system design and key technologies can provide reference for the construction of new power systems and energy Internet in the future oilfield industry. [ABSTRACT FROM AUTHOR]

The knowledge of the spatial distribution, sources, and air–soil exchange of polycyclic aromatic compounds (PACs) in an oilfield area is essential to the development of effective control practices of PAC pollution. In this study, 48 passive air samples and 24 soil samples were collected during 2018–2019 in seven functional areas (e.g., urban, oil field, suburban, industrial, agricultural, near pump units, and background) in the Yellow River Delta (YRD) where the Shengli Oilfield is located, and 18 parent polycyclic aromatic hydrocarbons (PAHs) and five alkylated-PAHs (APAHs) were analyzed from all the air and soil samples. The ΣPAHs in the air and soil ranged from 2.26 to 135.83 ng/m3 and 33.96 to 408.94 ng/g, while the ΣAPAHs in the atmosphere and soil ranged from 0.04 to 16.31 ng/m3 and 6.39 to 211.86 ng/g, respectively. There was a downward trend of atmospheric ΣPAH concentrations with increasing the distance from the urban area, while both ΣPAH and ΣAPAH concentrations in the soil decreased with distance from the oilfield area. PMF analyses show that for atmospheric PACs, coal/biomass combustion was the main contributor in urban, suburban, and agricultural areas, while crude production and processing source contributes more in the industrial and oilfield area. For PACs in soil, densely populated areas (industrial, urban, and suburban) are more affected by traffic sources, while oilfield and near-pump unit areas are under the impact of oil spills. The fugacity fraction ( f f ) results indicated that the soil generally emitted low-molecular-weight PAHs and APAHs and act as a sink for high-molecular-weight PAHs. The incremental lifetime cancer risk (ILCR) of Σ(PAH+APAH) in both the air and soil, were below the threshold (≤10−6) set by the US EPA. [ABSTRACT FROM AUTHOR]

Mono-chlorinated products of cyclic volatile methylsiloxanes (cVMS), i.e., Monochlormet-hylheptamethylcyclotetrasiloxane [D3D(CH 2 Cl)], monochlormethylnonamethylcyclopenta-siloxane [D4D(CH 2 Cl)], and monochlormethylundemethylcyclohexasiloxane [D5D(CH 2 Cl)], were detected in water [

In this work, we studied the application of photovoltaic solar energy for driving the electrochemical processes of electrocoagulation and electrooxidation to remediate drilling fluid wastewater, and simultaneously harvest energy in the form of electrolytic hydrogen gas produced at the cathode. The electrocoagulation was performed with sacrificial aluminium electrodes and electrooxidation with dimensionally stable boron-doped diamond electrodes in batch-wise and continuously operated mode, and their efficiency in both pollutants removal and hydrogen gas production was elucidated. The parameters affecting the efficiency of the applied electrochemical processes, such as applied current density, pH, electroprocessing time and flow rate, were investigated. The electrochemical processing was monitored by measuring the chemical oxygen demand (COD) of treated wastewater. The electrocoagulation treatment conducted with current densities of 30, 60 and 90 mA/cm2 reduced the wastewater COD by about 67%, whereas the electrooxidation treatment at the same conditions yielded a COD removal of over 95%. The amount of produced hydrogen was 171 L/g COD removed from treated wastewater. [ABSTRACT FROM AUTHOR]

Sulfated scaling of oilfield injected water has a great adverse effect on production.Based on the water quality analysis results of injected water, the trend of sulphate and carbonate scaling may be deduced.The scaling samples of injected water system were analyzed by X-ray diffraction (XRD). The results show that there was incompatibility between clean water and formation water and the scale samples were mainly barium strontium sulfate scale, and mixed with a small amount of calcium carbonate scale.The factors affecting the incompatibility of injected water in oil field were discussed and the prevention scheme was put forward. [ABSTRACT FROM AUTHOR]

The primary objective of this study was to assess differential vertical and horizontal deformations for the offshore Kashagan oilfield located in the Northern Caspian Sea. Sentinel-1 (SNT1) and COSMO-SkyMed (CSK) synthetic-aperture radar (SAR) images (9 January 2018–6 April 2022) were processed using persistent scatterer interferometric SAR (PS-InSAR) technique with further 2D decomposition of line-of-sight (LOS) measurements to differential vertical and horizontal deformations. Differential vertical deformation velocity was observed to be between −4 mm/y and 4 mm/y, whereas horizontal was between −4 mm/y and 5 mm/y during 2018–2022. However, it was possible to observe the spatial deformation patterns with the subsidence hotspots reaching differential cumulative vertical displacement of −20 mm from both satellite missions. PS-InSAR differential vertical deformation measurements derived from SNT1 and CSK satellite images showed identical spatial patterns with moderate agreement, whereas poor agreement was observed for differential horizontal deformations. The differential vertical deformation hotspots were observed for the oilfield areas installed on piles with obviously higher vulnerability to dynamic movements. Through this study, based on the interferometric measurements, marine geotechnical expert feedback, and no reported deformation-related incidents since 2013, it was possible to conclude that the Kashagan oilfield had not been impacted by significant differential vertical and horizontal deformations on the oilfield. However, since long-term GPS measurements were not accessible from the oilfield to be used as the reference for PS-InSAR measurements, we were not able to judge the long-term displacements of the entire oilfield or possible oscillations, even though it is built on the artificial island. Considering the broad range of PS-InSAR measurements using time-series radar images, the interferometric measurements could play a significant role in the prioritization of insitu risk assessment activities, operational cost reduction, strengthening of safety factors, and planning of further targeted insitu measurements.

The present study aimed firstly to use a set of crude oil samples and a dataset to provide new evidence for source input contribution in selected aromatic isomers for discrimination of oils from three oilfields from Tarim Basin and identify the key factor (s) controlling the isotope composition. Thus, the present research showed that the δ13C values of alkylnaphthalenes and alkylphenanthrenes plotted against P/DBT and Ga/C30H ratios is a reliable and convenient tool for discrimination of organic matter variations in different oilfields. More importantly, molecular ratios and different diagram plots revealed that the selected oil samples would be derived from a mixing of indigenous organic matter from the terrestrial (in Kuqa area) and marine (in the cratonic area) depositional environments prior the apparition of the Yakela Faulted Uplift. Thus, Daolaoba, Yakela, and Tahe oils were made up of organic materials from both marine and terrestrial sources. Furthermore, marine organic matter input dominates oils from the Tahe and Yakela, with a minor input from terrestrial sources. The oils from Daolaoba were assigned to be from a mixing of marine and terrestrial material inputs. The controlling factors assessment revealed that biodegradation has an insignificant effect on the set of oils; however, the source input and the thermal maturity together control the isotopic compositions of individual aromatic isomers from these three oilfields. [ABSTRACT FROM AUTHOR]

Positive Displacement Motors (PDM) are extensively used in the oilfield, either in drilling or in coiled tubing (CT) operations. They provide a higher rate of penetration and the possibility of drilling horizontal wells. For coiled tubing operations, PDMs can mill through obstructions and enable shut-in wells to work again. One of the major challenges while using these tools is the motor stalling, which can lead to serious damage to the PDM and lost time events in drilling and workover rigs. These events result in total losses of hundreds of thousands of dollars, and their avoidance mostly depends on trained and fully aware equipment operators. If a PDM starts to stall, the pumping needs to be halted immediately or the tool may fail. This paper describes the use of a Fuzzy Inference System (FIS) to detect the stalling events as they start to happen using the acquisition data from the coiled tubing unit, the output of the FIS could then trigger an alarm for the operator to take the proper action or remotely stop the pump. The FIS was implemented in Python and tested with real CT milling acquisition data. When tested using real data, the system analyzed 68,458 acquisition points and detected 94% of the stalling events across this data during its first seconds, whereas, during the real job, a CT operator could take longer to notice this event and take the proper action, or even take no action. If the FIS was applied on a real coiled tubing acquisition system, it could reduce PDMs over-pressurization due to stalling, leading to an increase on its useful life and decrease on premature failure. As of now there is no similar system in the market or published and this kind of operation is fully performed using human supervision only. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The knowledge of the spatial distribution, sources, and air–soil exchange of polycyclic aromatic compounds (PACs) in an oilfield area is essential to the development of effective control practices of PAC pollution. In this study, 48 passive air samples and 24 soil samples were collected during 2018–2019 in seven functional areas (e.g., urban, oil field, suburban, industrial, agricultural, near pump units, and background) in the Yellow River Delta (YRD) where the Shengli Oilfield is located, and 18 parent polycyclic aromatic hydrocarbons (PAHs) and five alkylated-PAHs (APAHs) were analyzed from all the air and soil samples. The ΣPAHs in the air and soil ranged from 2.26 to 135.83 ng/m3 and 33.96 to 408.94 ng/g, while the ΣAPAHs in the atmosphere and soil ranged from 0.04 to 16.31 ng/m3 and 6.39 to 211.86 ng/g, respectively. There was a downward trend of atmospheric ΣPAH concentrations with increasing the distance from the urban area, while both ΣPAH and ΣAPAH concentrations in the soil decreased with distance from the oilfield area. PMF analyses show that for atmospheric PACs, coal/biomass combustion was the main contributor in urban, suburban, and agricultural areas, while crude production and processing source contributes more in the industrial and oilfield area. For PACs in soil, densely populated areas (industrial, urban, and suburban) are more affected by traffic sources, while oilfield and near-pump unit areas are under the impact of oil spills. The fugacity fraction (ff) results indicated that the soil generally emitted low-molecular-weight PAHs and APAHs and act as a sink for high-molecular-weight PAHs. The incremental lifetime cancer risk (ILCR) of Σ(PAH+APAH) in both the air and soil, were below the threshold (≤10−6) set by the US EPA.

Production chemistry is an important field in the petroleum industry to study the physicochemical changes in the production system and associated impact on production fluid flow from reservoir to topsides facilities. Mineral scale deposition and metal corrosion are among the top three water-related production chemistry threats in the petroleum industry, particularly for offshore deepwater and shale operations. Mineral scale deposition is mainly driven by local supersaturation due to operational condition change and/or mixing of incompatible waters. Corrosion, in contrast, is an electrochemical oxidation–reduction process with local cathodic and anodic reactions taking place on metal surfaces. Both mineral scaling and metal corrosion can lead to severe operational risk and financial loss. The most common engineering solution for oilfield scale and corrosion control is to deploy chemical inhibitors, including scale inhibitors and corrosion inhibitors. In the past few decades, various chemical inhibitors have been prepared and applied for scaling and corrosion control. Phosphorus-based polymers are an important class of chemical inhibitors commonly adopted in oilfield operations. Due to the versatile molecular structures of these chemicals, phosphorus-based polymeric inhibitors have the advantage of a higher calcium tolerance, a higher thermal stability, and a wider pH tolerance range compared with other types of inhibitors. However, there are limited review articles to cover these polymeric chemicals for oilfield scale and corrosion control. To address this gap, this review article systematically reviews the synthesis, laboratory testing, and field applications of various phosphorus-based polymeric inhibitors in the oil and gas industry. Future research directions in terms of optimizing inhibitor design are also discussed. The objective is to keep the readers abreast of the latest development in the synthesis and application of these materials and to bridge chemistry knowledge with oilfield scale and corrosion control practice. [ABSTRACT FROM AUTHOR]

The classic filtration model is based on inorganic particles and filter media and was designed for urban wastewater treatment without considering the characteristics and particle size distribution of oil-field produced water; thus, this model cannot accurately predict the filtration process of oily water from oil fields. The parameter design of the filter bed depends on experience, which separates the connection with filtration models. Based on these shortcomings, this study investigates the effects of various parameters on filtration efficiency and filtration rating using the Yao-Tien filtration model and simulations. The dominant mechanism and its transformation law of the oil-field filter are discussed, and the role of straining in the fine filter cannot be ignored. The role of the wettability of organic media in oil-field filters is emphasized, and the corresponding empirical parameters should be introduced into the correction model. [ABSTRACT FROM AUTHOR]

Copyright of Acta Sedimentologica Sinica is the property of Acta Sedimentologica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In traditional polymer flooding technology, the flooding effect is affected by mechanical degradation, adsorption, dilution of polymer molecules during formation, and injection concentration variations. In the application of polymer flooding technology, how to optimize the polymer type and injection parameters to improve the oil displacement effect is very important. This paper conducts simulation experiments on polymer type, injection concentration, injection volume, etc., and evaluates the advantages of two polymers for flooding through the recovery factor and injection pressure. Studies have shown that when the concentration of ordinary intermediate polymer solution is 1200 mg/L and the concentration of salt-resistant polymer solution is 700 mg/L, the oil displacement effect for X low permeability reservoir is the most obvious. When the injection volume of two polymer solutions is 0.64 PV, the two polymers have the best increase in oil recover. When natural cores are used to study the oil displacement effect, salt-tolerant polymer floods the enhanced oil recovery value to 13.32%, which is higher 10.1% than that of ordinary middle-separation polymerization. Moreover, considering the polymer flooding effect and input cost, the pollution-distributed dilute salt-resistant polymer solution is used for flooding. The optimal injection concentration of the salt-resistant polymer solution is 700 mg/L and the optimal injection volume is 0.64 PV. [ABSTRACT FROM AUTHOR]

In order to obtain the dominant strain with high salt and oil content, the indigenous bacteria from aging contaminated soil of Xinjiang Baijiantan oilfield was artificially acclimated, and the changes of physicochemical parameters of culture medium were investigated. As is shown in the results, the increasing turbidity and optical density indicated that a certain number of strains adapted to high salt (70000mg/L) and high oil (8100mg/L) stress were successfully domesticated in a short period (72h); pH decreased from 7.6 to 5.9, because petroleum hydrocarbon degradation may produce carboxylic acid, CO2 and other acidic substances; under the influence of pH decreasing trend, oxidation-reduction potential increased gradually; in a single acclimation stage, halophilic bacteria gradually adjusted osmotic pressure to adapt to higher salt and oil stress conditions. [ABSTRACT FROM AUTHOR]

Field and laboratory investigations were conducted to characterize the composition of petroleum hydrocarbons in oily sludge and the underlying contaminated soils in a decommissioned oilfield waste pit in Kuwait. The results show that the petroleum hydrocarbon composition in the oily sludge and contaminated soils was spatially variable. Highly toxic petroleum hydrocarbon species such as BTEX and PAHs were generally lacking, and both sludge- and soil-borne hydrocarbons were dominated by long-chain petroleum hydrocarbons. The soil contamination depth was generally very shallow although localized deep profiles (>0.5 m) were found. A loose relationship was established between TPH in the sludge and that in the underlying soil. On average, the soil had a greater percentage of shorter-chain hydrocarbon fractions (either aliphatics or aromatics), as compared to the sludge. The environmental risk from the oily sludge and contaminated soils is considered to be relatively low. For cost-effective management of the environmental risk of decommissioning an oilfield waste pit, containment of the sludge and contaminated soils using a soil-capping approach may be sufficient to minimize the possible adverse environmental impacts from the decommissioned waste pit, and this may represent an option that is superior to other costly remediation strategies. [ABSTRACT FROM AUTHOR]

Oil production forecasting is an important task to manage petroleum reservoirs operations. In this study, a developed time series forecasting model is proposed for oil production using a new improved version of the adaptive neuro-fuzzy inference system (ANFIS). This model is improved by using an optimization algorithm, the slime mould algorithm (SMA). The SMA is a new algorithm that is applied for solving different optimization tasks. However, its search mechanism suffers from some limitations, for example, trapping at local optima. Thus, we modify the SMA using an intelligence search technique called opposition-based learning (OLB). The developed model, ANFIS-SMAOLB, is evaluated with different real-world oil production data collected from two oilfields in two different countries, Masila oilfield (Yemen) and Tahe oilfield (China). Furthermore, the evaluation of this model is considered with extensive comparisons to several methods, using several evaluation measures. The outcomes assessed the high ability of the developed ANFIS-SMAOLB as an efficient time series forecasting model that showed significant performance. [ABSTRACT FROM AUTHOR]

Application of water flooding technologies in the oilfield causes intensive heterogeneity of the oil reservoir and improper circulation of the injected water. The profile control and water plugging technologies are applied to adjust the heterogeneity of the formation, reduce permeability, plug the formation water, and enhance the oil recovery. The polymer gel used in the profile control and water plugging method is produced by mixing the polymer solution with an appropriate crosslinking agent. In this study, the organic-chromium gel is prepared by mixing the partially-hydrolyzed polyacrylamide (HPAM) as the main component and the organic chromium as a crosslinking agent. The resulting gel contains 1% of HPAM and 1% of the organic-chromium crosslinking agent. The gelatinization of the solution is evaluated by measuring the gel parameters in relation to temperature, pH value, and salinity parameters of the solution. The plugging effectiveness of the gel is tested experimentally in the simulated artificial strata. Based on the optimized temperature, salinity, and pH parameters, the gel solution formula has been adjusted. The optimized gel is characterized by the gelation time in the range from 1 to 22 h, the gel strength as high as the I level, and the plugging rate of above 95%, providing a satisfactory plugging effect in the simulated formation. The experimental results can provide theoretical and practical references for developing water-plugging technologies in oilfields or mines. The study is also of interest for optimizing the formulations of the drilling fluids and the polymer-polymer compositions for enhanced oil recovery. [ABSTRACT FROM AUTHOR]

The fine description of the glutenite reservoir is the basis for clarifying the remaining oil distribution and rationally guiding the development of the block. Kunbei oilfield is located near the Kunbei fault terrace belt, which is one of the key exploration and evaluation oil areas in Qaidam Basin. Taking Qie-12 block as an example, the characteristics of glutenite reservoir in Xiaganchaigou Formation are studied by using GeoFence software, and the alluvial fan sedimentary model is adopted. The methods of scanning electron microscopy, casting thin section and 3D seismic data are used to analysis the physical property. The results show that the reservoir rocks in the study area are mainly small conglomerate and breccia, and the mineral content is mainly quartz and feldspar. The average porosity and permeability of reservoir is 9.27% and 4.59mD respectively, which is a low porosity and ultra-low permeability reservoir. The physical characteristics reveal that the order of the microfacies from good to poor is braided channel, overflow sand body and sheet flow gravel microfacies. The results of heterogeneity indicate that the interlayer heterogeneity of E3¹ section is weak as a whole, while the intralayer heterogeneity is strong, and the plane reservoir quality index is mainly between 0.12~0.48, which is mainly developed in the middle area of alluvial fan. In addition, we classifies the oil layers in Qie-12 block, and determines the distribution areas of oil sands of Type I and II reservoirs. [ABSTRACT FROM AUTHOR]

The relevance of the study is caused by the need to summarize the accumulated experience and information on application of generally accepted methods for analyzing the effectiveness of the pressure maintenance system, identifying the advantages and disadvantages of each individual method, and formulating recommendations to simplify the efficiency analysis, while increasing the depth and quality of the analysis, which in the future will reduce production losses oil. The research aim is to formulate recommendations for improving the process of analyzing the effectiveness of the oil flooding system. The research subject: southern licensed territory of the Priobskoe field (Khanty-Mansi Autonomous Okrug). The research methods: correlation analysis of existing methods of evaluation of water-flooding oil reservoirs, identification of strengths and weaknesses, development of an integrated approach to the use of methods of analysis of effectiveness of waterflood, and assessment of prospects of application of research results. The research results. The paper discusses a methodology for optimizing the process of analyzing the effectiveness of a waterflooding system for oil fields by dividing them into smaller hydrodynamically closed sections of the reservoir – blocks (waterflood cells). To prevent loss of quality of the analysis, a transition from a reactive approach to diagnosing losses to a proactive one is proposed, which allows predicting and preventing a decrease in oil production. Based on the tendency to enlarge the sections of the reservoir to be analyzed, in comparison with traditional methods of analysis, and implement a proactive approach, an algorithm is proposed to increase the efficiency of base production management – proactive block factor analysis. The prospects of applying the results of block-factor analysis on the example of one of the blocks of the Priobskoe field (Khanty-Mansi Autonomous Area) is considered. It is possible to adapt the presented analysis algorithm to the necessary geological and physical conditions of other layers in order to adapt this technology in other oil and gas provinces.

For an increasing implementation of the low-temperature transportation in oilfield, it is urgent priority initially to study the physical and chemical properties to provide the vital technical support for the low-temperature transport of the polymer flooding. In this paper, the rheological behavior of polymer-containing fluid produced from the Daqing polymer flood were first studied for an adaptation of transportation under the oil’s freezing point temperature. The experiments progressed with different temperature, shear rate, water content and polymer concentration which have great impacts on the viscosity of the fluids produced aiming to find the phase transportation point for the application of the low-temperature transportation. It was displayed that a significant discontinuity in the viscosity occurs at some range of water content. Before the phase transition point, presented in W/O (water-in-oil) emulsion, the viscosity was lifted with the increase of the water content while after the phase transition point, forming the O/W (oil-in-water) type emulsion, the viscosity was dropped with an increase of water content. The phase transition points strongly depend on the polymer concentration in the fluids Produced. It was demonstrated that the phase transition points of polymer-containing fluids were 65%, 70%, 50%, 50% and 50%, corresponding to the polymer concentrations of 315mg/L, 503mg/L, 708mg/L, 920mg/L and 1053mg/L, respectively. The characteristics are attributed to the viscous polymer. The fluidity of the fluid produced was decreased with the increase of polymer concentration.

Produced water is a large amount of water wasted throughout the crude oil extraction process, it's a mixture of the well's deposition water and the water of oil wells extraction water. Produced water contains oil, suspended solids and dissolves solid. This study tested produced water collected from Alahdab oilfield/middle oil company for oil content and suspended solid contamination using chemical precipitation and coagulation-flocculation for reinjection and environmental considerations. Coagulation/flocculation is a common method used as primary purification to oily wastewater treatment due to its usability, performance, and low cost. Coagulant experimental was completed by A jar test device, additives of ferric sulfate and aluminium sulfate were in a range about (40 10) ppm, as well as polyelectrolyte-(polyacrylamide) as an additional flocculent in the range (1.5-3) ppm. The results show that ferric sulfate was more efficient at removing turbidity than aluminium sulfate under the same conditions, with the best removal of turbidity at dose concentration 30 ppm of Ferric sulfate and a flocculent dose concentration of 2.5 ppm of polyacrylamide, also with oil content decreasing from 396.71 ppm to 53.56 ppm. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Petrochemical Universities / Shiyou Huagong Gaodeng Xuexiao Xuebao is the property of Journal Editorial Department Of Liaoning Shihua University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Positive Displacement Motors (PDM) are extensively used in the oilfield, either in drilling or in coiled tubing (CT) operations. They provide a higher rate of penetration and the possibility of drilling horizontal wells. For coiled tubing operations, PDMs can mill through obstructions and enable shut-in wells to work again. One of the major challenges while using these tools is the motor stalling, which can lead to serious damage to the PDM and lost time events in drilling and workover rigs. These events result in total losses of hundreds of thousands of dollars, and their avoidance mostly depends on trained and fully aware equipment operators. If a PDM starts to stall, the pumping needs to be halted immediately or the tool may fail. This paper describes the use of a Fuzzy Inference System (FIS) to detect the stalling events as they start to happen using the acquisition data from the coiled tubing unit, the output of the FIS could then trigger an alarm for the operator to take the proper action or remotely stop the pump. The FIS was implemented in Python and tested with real CT milling acquisition data. When tested using real data, the system analyzed 68,458 acquisition points and detected 94% of the stalling events across this data during its first seconds, whereas, during the real job, a CT operator could take longer to notice this event and take the proper action, or even take no action. If the FIS was applied on a real coiled tubing acquisition system, it could reduce PDMs over-pressurization due to stalling, leading to an increase on its useful life and decrease on premature failure. As of now there is no similar system in the market or published and this kind of operation is fully performed using human supervision only.

The present study aimed firstly to use a set of crude oil samples and a dataset to provide new evidence for source input contribution in selected aromatic isomers for discrimination of oils from three oilfields from Tarim Basin and identify the key factor (s) controlling the isotope composition. Thus, the present research showed that the δ13C values of alkylnaphthalenes and alkylphenanthrenes plotted against P/DBT and Ga/C30H ratios is a reliable and convenient tool for discrimination of organic matter variations in different oilfields. More importantly, molecular ratios and different diagram plots revealed that the selected oil samples would be derived from a mixing of indigenous organic matter from the terrestrial (in Kuqa area) and marine (in the cratonic area) depositional environments prior the apparition of the Yakela Faulted Uplift. Thus, Daolaoba, Yakela, and Tahe oils were made up of organic materials from both marine and terrestrial sources. Furthermore, marine organic matter input dominates oils from the Tahe and Yakela, with a minor input from terrestrial sources. The oils from Daolaoba were assigned to be from a mixing of marine and terrestrial material inputs. The controlling factors assessment revealed that biodegradation has an insignificant effect on the set of oils; however, the source input and the thermal maturity together control the isotopic compositions of individual aromatic isomers from these three oilfields.

In this study, the configuration anatomy of braided river delta in Ying-14 fault block of Dongxin Oilfield was carried out under the condition of dense well pattern. The reservoir configuration model of braided river delta suitable for the target area was established based on core and logging data. The results shows that in the early stage of deposition, the water is relatively deep, and the branch of underwater distributary channel is mainly bifurcation diversion. In the middle stage, the water becomes shallower, the river channel evolves from underwater to water, and the branch of the river channel evolves from the bifurcation diversion to the lateral crevasse of the river channel. In the late stage, the water deepened again, and the underwater distributary channel and single estuary dam developed, but the scale was relatively small in the early stage. In the delta vertical evolution process, the sand body superimposed phenomenon first weakened and then enhanced, lateral erosion, splicing phenomenon gradually obvious. The distributary channel sand bodies in the upper part of the Es2 is intermittently deposited in the vertical direction. The connectivity of the sand bodies in the transverse direction is good. The horizontal channel is narrow strip, and the channel crossing is rare. The estuary dam in the lower part of Es2 is vertically cut and overlapped, the interlayer in the main body of the dam is downward curved, the dam edge is distributed at the wing end, and the underwater distributary channel sand is embedded in the main body of the dam, showing the sedimentary model of river runs between the dams. [ABSTRACT FROM AUTHOR]

Different thickness of oily sludge has different effect on the quality of pyrolysis residue. In order to improve the treatment effect of oily sludge in oilfield, the mechanism of low temperature pyrolysis of oily sludge was investigated, and Daqing Oilfield of China was ta.ken as example. The whole pyrolysis reaction of oil sludge with different physical quality was carried out intermittently at atmospheric pressure. The treatment process is divided into temperature control system, pyrolysis reaction system, product condensation system, tail gas metering and treatment system to obtain the value of pyrolysis residue mineral oil. The optimum pyrolysis temperature was determined to be 500 °C, pyrolysis time was 30 min, and the output quality was obviously better than the quality ofrecovered oil, so as to complete the study of low temperature pyrolysis mechanism of oily sludge. The experimental r esults show that the higher the pyrolysis temperature, the stronger the heat cracking reaction. When the temperature is higher than 550 °C, the pyrolysis oil production begins to decrease. The higher the pyrolysis time, the lower the value of mineral oil, when it is in about 50 min, it gradually stabilizes. Different thickness of oily sludge has certain effect on the quality of solid residue after pyrolysis, and the pressure affects the gas injection effect in Daqing Oilfield. [ABSTRACT FROM AUTHOR]

The traditional fracturing fluid flowbackrecovery process is complex, inefficient and costly, which significantly increases the operating pressure of oilfield sewage treatment. In this study, an environment- friendly fracturing fluid without flowback was developed and successfully applied to the actual production test of oil field. In order to meet the needs of large-scale applications, a cost reduction research was carried out. Through the research and development of a viscosity enhancer, its use induced a hydrophobic effect, which could effectively improve the performance of the fracturing fluid. Compared with the former, the amount of surfactant in the 90 °C formula was reduced by 20 %, and the cost per cubic meter decreased by 14.2 %. At present, a total of 42 wells have been applied. Among these, the daily oil production of wells was 2.4 times of that before the measures, the daily injection volume of water was 3.3 times of that before the measures, and the backflow and haulage treatment fluid was reduced by 0.75x104 m3. On one hand, the environmental protection pressure of grassland and peripheral forest farm construction was significantly reduced. On the other hand, it meets the requirements of pollution reduction and emission reduction in the process of oilfield production. [ABSTRACT FROM AUTHOR]

At present, the focus of exploration and development has gradually shifted from conventional oilfields to ultra-low permeability oilfields. Due to the influence of illite resistivity, the traditional exploration technology for ultra-low permeability oilfield cannot accurately locate the ultra-low permeability oilfield. Therefore, taking Xuecha oil area of Wuqi oilfield as an example, the analysis model of influencing factors of illite resistivity in ultra-low permeability oilfield is established. The resistivity structure of soil rock series, parallel resistivity structure of soil rock structure, series parallel hybrid resistivity structure of soil rock structure, water content resistivity inversion, porosity resistivity inversion, and dry density resistivity inversion are obtained respectively. Based on this, the experiment is designed. The results show that the resistivity of illite increases with the increase of water content, porosity, dry density, water content, and compaction time, and the confidence coefficient model is higher than 0.9600. The experimental results show that this method can be applied to analyze the influencing factors of illite resistivity in ultra-low permeability oilfield. [ABSTRACT FROM AUTHOR]