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Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) 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 accurate determination of reservoir lithology remains a challenge in petroleum engineering. There are some conventional techniques available to determine the lithology. However, the application of those techniques has been long and complex. So, the main goal of this study is to simplify the identification of reservoir lithology. This paper presents a Pattern Recognition Approach (PRA) to identify the reservoir lithology simply and accurately. It is type of artificial neural network. Four wells from the Camaal Field were chosen to develop this approach. Around 32400 data points from the previous wells were digitized. The PRA approach used depth, gamma ray, lithology, sonic, neutron, and density logs as inputs. The model classifies lithology into permeable and impermeable rocks, further categorizing them into clastic and carbonate rocks, and subsequently into specific types into sand, sandstone, dolomite and limestone. The results show that the proposed approach provides a suitable prediction of lithology with higher accuracy compared with actual lithology. The model demonstrates high accuracy rates in identifying various lithologies, with overall accuracies of 76.2% for permeable/impermeable rocks, 94.9 for clastic/carbonate rocks, 86.2% for sand/sandstone, and 92.8% for dolomite/limestone.

Both sedimentological factors and secondary processes of lithogenesis influenced the formation of porosity and permeability properties of the reservoir rocks of the Vikulov suite of the Krasnoleninskoe field. The former includes the conditions of sedimentation of the deposits of the Vikulov suite, which at the initial stages of its formation were controlled by the development of a system of incised river valleys, the stages of filling of which, like their composition, have their own characteristics. Also, various genetic types of deposits were formed here. The formation of the upper part of the Vikulov suite took place in a shallow-marine setting, in conditions of storm and wave shallow water, which affected the thin-layered structure of the VK1-3 reservoir. On the other hand, in the sections of a number of wells, dense interlayers are noted, the formation of which is associated with both sedimentation and superimposed processes in lithogenesis, including the formation of hydrocarbon deposits. Therefore, the prediction of the distribution of productive reservoir rocks is the main task when creating a petrophysical model of the field, and to solve this problem, the methods of lithofacies and staged core analysis are used in the work.

Abstract Rock types are the reservoir's most essential properties for special facies modeling in a defined range of porosity and permeability. This study used clustering techniques to identify rock types in 280 core samples from one of the wells drilled in the Asmari reservoir in the Mansouri field, SW Iran. Four hydraulic flow units (HFUs) were determined for studied data utilizing histogram analysis, normal probability analysis, and the sum of squared errors (SSE) statistical methods. Then, two flow zone index (FZI) and fuzzy c-means (FCM) clustering methods were used to determine the rock types in the given well according to the results obtained from the HFU continuity index acts in-depth. The FCM method, with a continuity number of 3.12, compared to the FZI, with a continuity number of 2.77, shows more continuity in depth. The relationship between permeability and porosity improved considerably by utilizing HFU techniques. This improvement is achieved using the FZI method study. Generally, all samples increased from 0.55 to 0.81 in the first HFU and finally to 0.94 in the fourth HFU. Similar flow properties in an HFU characterized the samples. In comparison, the correlation coefficients obtained in the FCM method are less than those in the general case of all HFUs. This study aims to determine the flowing fluid in the porous medium of the Asmari reservoir employing the c-mean fuzzy logic. Also, by determining the facies of the rock units, especially the siliceous-clastic facies and log data in the Asmari Formation, the third and fourth flow units have the highest reservoir quality and permeability. Results can be compared to determining HFU in nearby wellbores without cores.

We used the geological map and published rock density measurements to compile the digital rock density model for the Hong Kong territories. We then estimated the average density for the whole territory. According to our result, the rock density values in Hong Kong vary from 2101 to 2681 kg·m−3. These density values are typically smaller than the average density of 2670 kg·m−3, often adopted to represent the average density of the upper continental crust in physical geodesy and gravimetric geophysics applications. This finding reflects that the geological configuration in Hong Kong is mainly formed by light volcanic formations and lava flows with overlying sedimentary deposits at many locations, while the percentage of heavier metamorphic rocks is very low (less than 1%). This product will improve the accuracy of a detailed geoid model and orthometric heights.

This research is aimed at using statistical analysis to predict the overall performance of subsoil derived from three rock types in Southwestern, Nigeria, for pre- and post-engineering construction. Twelve subsoil samples were obtained along Ogbagi Akoko road and thirty articles were reviewed for statistical analysis of Pearson correlation coefficient (PCC) and analysis of variance (ANOVA). Subsoil samples from Ogbagi are sufficiently good because they meet the Nigerian specification. Comparing the statistical values of the soil samples derived from the three rock types, igneous, metamorphic, and sedimentary rocks have combined strong positive and negative pairwise parameter values of 31, 25, and 14 respectively. Igneous rock derived soil has more positive pairwise PCC (20) and better ratings in 30 pairwise parameters when compared with the other two rock types. Two strong positive (PL-LL and FINES- LL) and one negative (COARSE–FINE) pairwise PCC of the same variables are common to the three rock types derived soils. For coefficient of determination (r2), igneous rock derived soil has excellent (> 75%) and good (< 75–50) ratings (26) than sedimentary rock (18) and metamorphic rock (8) derived soils with only one variable of high similarity index (> 75%) (COARSE-FINES) common to the three rock types derived soil. For ANOVA analysis, the critical r values of all the parameters are by far higher than the test values for all the parameters. We therefore fail to reject the null hypothesis. [ABSTRACT FROM AUTHOR]

Copyright of Anuario do Instituto de Geociencias is the property of Universidade Federal do Rio de Janeiro, Instituto de Geociencias 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.)

Purpose: Radon (222Rn) and its decay products clinging to airborne particles settle in the lungs when inhaled and can lead to lung cancer. The main source of 222Rn is rocks and soil in the Earth's crust and causes indoor radon exposure when local geological material is used as a building material. Accordingly, the primary aim of the study is to determine the radon activity concentrations (CRn) and exhalation rates (EA and EM) from different rock types taken from the Aliağaİzmir region. The study also estimates the annual effective dose (AED) and the excess lifetime cancer risk (ELCR). Material and Methods: For the measurement of the CRn, EA, and EM in different rock types, the Can technique with LR-115 detector was utilized. The AED and the ELCR were estimated using the CRn in the samples. Results: The results for the examined rock samples were ranged between 66±4 and 1711±13 Bq m-3 for CRn, between 51±3 and 1309±10 mBq m-2 h-1 for EA, between 2.68±0.18 and 64.02±0.47 mBq kg-1 h-1 for EM, between 1.67 and 43.16 mSv y-1 for AED, and between 0.006 and 0.151 for ELCR. Conclusion: The higher radiological risks in terms of radon exposure were related to the rocks of volcanic origin. [ABSTRACT FROM AUTHOR]

This study quantifies the petrophysical parameters and determines the impact of mineralogy on the petrophysical parameters of the Permian sediments of the main Karoo Basin, South Africa. Conventional well logs from KDD-01 well, thirty-two and forty-two samples are investigated for mineral and composition analyses using X-ray diffraction and fluorescent techniques, respectively. Three intervals of Abrahamskraal Formation (500–513m), dolerite sill that intruded the Abrahamskraal Formation (513–530m), and Waterford Formation (1014–1048m) are investigated. The results show that the average porosity of the Abrahamskraal Formation is 2.9%, the dolerite interval has an average value of 1.8%, whereas the Waterford Formation has an average value of 2.1%. The average permeability for the Abrahmaskraal Formation is 0.05mD, dolerite 0.04mD, and the Waterford Formation is 0.08mD, respectively. No hydrocarbon was detected. The low values of petrophysical properties may be associated with the pore network, which is poorly connected, intense precipitation of secondary minerals, and pore infilling during burial diagenesis. Quartz mineral dominates in the Abrahamskraal Formation, with an average value of 47% and 61% in the Waterford Formation.In comparison, plagioclase is the main mineral constituent in the dolerite, with an average of 44%. Based on the combined petrophysical and geochemistry classification scheme, the formations evaluated belong to the type III pore structure. The type III pore structure is a poor and ineffective reservoir, with rock porosity usually less than 6% and a permeability of less than 0.15mD. However, regarding the mineral elemental ratio, the Abrahamskraal and the Waterford Formations meet the type II pore structure criteria, while the dolerite is type III. This paper has produced a helpful rock classification scheme based in the Karoo Basin, South Africa, using petrophysical and geochemical data for the first time. • The Abrahamskraal and the Waterford Formations evaluated belong to the type III pore structure based on petrophysical and geochemical grouping. • The low values of petrophysical properties are associated with the pore network. • No hydrocarbon was detected in these formations. • Plagioclase is the main mineral constituent in the dolerite intruded interval. • Useful rock classification scheme produced using petrophysical and geochemical data. [ABSTRACT FROM AUTHOR]

Reliable and accurate determination of water saturation above the oil-water contact of the hydrocarbonbearing formations is essential for calculating hydrocarbon in place. In this study, water saturations were measured directly from 160 core samples by Dean-stark test in one well and thin sections have been used to identify geological properties. Archie coefficients were also determined on plug samples. The water saturation values obtained from the electrical models including Archie, Waxman-Smith, and dual water were measured in Geolog7 software and applied in Kangan and Dalan formations in one of the fields in the Central Persian Gulf. In this study, four methods have been used to determine the rock types, including Winland, reservoir quality index, pore type, and depositional texture to identify the parameters affecting the distribution of water saturation. Results showed that pore throat radius is a parameter that affects water saturation and this parameter is directly related to the increased permeability and reduction of the difference between the water saturation values of Archie with the Dean-stark test. Determination of rock types based on depositional texture and pore type revealed that the cement type and texture and the pore types, control the permeability and distribution of water saturation in the reservoir. It was also found that depositional texture, unlike pore throat radius, well separates sedimentary environments. The results of water saturation calculations showed that if the Archie coefficients are calculated in each flow unit, the water saturation resulting from it would be very close to the water saturation values in the core (Dean-Stark). The electrical model of water saturation, with different coefficients in samples with different reservoir quality index or pore types, yields the most accurate water saturation values compared to Dean-Stark. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. 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.)

Copyright of Review of the Bulgarian Geological Society is the property of Bulgarian Geological Society 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.)

Abstract Eocene to Oligocene–Miocene carbonates of Jahrum and Asmari formations form the reservoirs of the Khesht Field in the Fars Province, the Zagros Foreland basin. In this study, the reservoir characteristics of the upper parts Jahrum Formation in the Khesht Oil Field have been investigated based on the combination of facies analysis and diagenetic features of samples in the porosity-permeability framework. The Jahrum Formation in the Fars Province is mainly composed of limestones that formed on a laterally continuous carbonate ramp with significant variations in reservoir heterogeneity and quality. Petrographic studies led to the identification of five carbonate microfacies. Five petrophysical rock types (RT) in KH-02 well are recognized by considering primary and secondary controls on pore type and size distribution. From RT1 with no reservoir property toward RT5 reservoir quality is enhanced. Diagenetic features have significantly affected reservoir properties by both enhancing and destroying porosity and permeability. Bivariate plots of porosity and permeability, combined with thin-section petrography indicate that pervasive anhydrite cement and compaction had the greatest negative impact on reservoir quality, whereas, dolomitization, fracturing, and dissolution of Nummulites played the most positive role. Therefore, the general characteristics of the Jahrum reservoir in the Khesht Field are mainly shaped by diagenetic features. Using CycloLog software in the two studied wells led to the identification of two sedimentary cycles within the Jahrum Formation. The negative trend of the INPEFA log (sea-level fall) in the second sedimentary cycle includes the upper part of the Jahrum Formation which has medium to high reservoir quality. Keywords: Reservoir zonation, Rock types, Diagenesis, Cyclolog Software, Jahrum Formation. Introduction Carbonate reservoirs are difficult to describe and produce a realistic picture of reservoir properties due to the vertical and lateral heterogeneity in various categories including lateral distribution of facies (Alsharhan 2006; Dou et al. 2011) and complex diagenetic evolution of carbonates (Lucia 2007; Ahr 2008; Rong et al. 2012; Moore 2013). Carbonates of the Jahrum Formation in Fars province together with the Asmari Formation form the main part of reservoirs in SW Iran. So far, no study has been conducted to investigate the reservoir characteristics of the Jahrum Formation in the Khesht oil field. These carbonates are generally deposited in a shallow marine environment, and the estimated porosity from thin-section petrographic studies show that due to the abundance of lime mud and low textural maturity, their reservoir capacity was low in the time of deposition (Hassanvand 2016). Therefore, due to the low primary porosity in most parts of the Jahrum Formation, it seems that the reservoir quality of this formation largely depends on the development of secondary porosity as a result of the performance of various diagenetic processes such as dolomitization (Azomani et al. 2013), fracturing and dissolution. Due to the importance of reservoir studies and the investigation of the distribution of reservoir properties, the combination of facies analysis and diagenetic characteristics of the Jahrum Formation samples in the framework of porosity and permeability were used for reservoir zonation in Khesht-2 well and the studied rocks were divided into different rock types. Also, the identifying sedimentary cycles of the Jahrum carbonate succession and reservoir correlation in KH-02 and KH-03 wells were performed using Cyclolog software. Material and Methods Petrographic analysis of thin sections together with petrophysical wire logs, porperm data, and core descriptions were used for Jahrum reservoir zonation in the Khesht oil field. In this way, 40 m of cores and 80 thin sections from KH-02 well were used to investigate facies distribution and diagenetic processes in the studied interval. All thin sections stained for dolomite identification using Dickson (1965) method and limestone classification has been done according to Dunham's (1962) and Embry and Klovan (1971) schemes. Facies analysis and interpretation of the depositional environment was performed using the standard microfacies classification by Wilson (1975) and Flügel (2010). We followed Lucia (1995, 2007) for reservoir quality characterization and identification of rock types. Determination of sedimentary cycles and reservoir correlation between the studied wells has been done by using CycloLog software and gamma-ray log. Discussion of Results & Conclusion The Late Eocene Jahrum Formation in the Khesht oil field, SW Iran has mainly composed of limestones lithology. Petrographical studies led to identifying five carbonate microfacies in the Jahrum succession which have been deposited on a homoclinal carbonate ramp. These microfacies are consists of F1) Echinoid Orbitolites Nummulites wacke/pack/rudstone - inner ramp (restricted lagoon); F2) Nummulites Echinoid packstone to grainstone - inner ramp (shoal); F3) coral boundstone - inner to mid ramp; F4) Echinoid Nummulites wackestone - mid ramp (open marine); F5) Bioclast dolostone (shallow burial environment). The Jahrum carbonates have been subjected to a variety of diagenetic processes including micritization, dolomitization, cementation, dissolution, fracturing, and styloliteration in the three diagenetic realms including marine, meteoric, and shallow to deep burial. The wide range of porosity and permeability values in most facies of the Jahrum Formation shows that the sedimentary texture of the studied samples alone did not control the reservoir quality. The reservoir quality of the studied succession is mainly controlled by different diagenetic processes. Petrographic studies along with porosity and permeability cross plots for the studied samples show that the combination of the dolomitization, dissolution, and fracture processes played the greatest role in improving the reservoir quality of the studied formation, but calcite and anhydrite cementation; especially pervasive dolomitization type and compaction, have reduced the reservoir quality of the studied succession. The INPEFA stratigraphy approach has identified two sedimentary cycles within the Jahrum succession with good correlation in both KH-02 and KH-03 wells. Reservoir quality is significantly better during sea-level fall than when sea level was high in both sedimentary cycles. Overall, the Jahrum Formation is deposited in a regression cycle that begins with the deposition of open marine microfacies on the Pabdeh Formation and ends with the deposition of echinoid Orbitolites Nummulites wackestone/packstone (F1) at the end of the sequence in a lagoonal environment at the boundary of the Asmari Formation. Using CycloLog software and correlation between the reservoir zones of the Jahrum Formation in Khesht Oil Field and the identified timelines reveals that some reservoir zones show good compatibility. However, some of these zones do not correspond to the timelines. By considering other cyclo-stratigraphic factors along with lithology, porosity, and permeability data, revision in Jahrum reservoir zonation in the Khesht Oil Field is needed.

Resource modeling plays a crucial role in raw material quality management for cement manufacturing. Research has shown that geological uncertainty in resource modeling is inevitable and results in risk to future extraction planning and operations of the cement plant. This study aims to assess the geological uncertainty and associated risk in modeling a cement raw material deposit in southern Vietnam. For this deposit, soil, clay, laterite, and limestone are the four primary rock types, controlling the occurrence and spatial distribution of chemical grades. In this study, hierarchical simulation method was used to evaluate the uncertainty. Rock types were first simulated, and the chemical grades conditioning to the rock types were then generated. The results demonstrated the capability of the hierarchical simulation approach to incorporate the uncertainty of rock types in resource modeling and to allow evaluating the risks in providing the desired raw material for the cement plant in the form of grade-tonnage curves.

Copyright of Geominas is the property of FUNDA-GEOMINAS. (Fundacion de Egresados d Amigos de la Escuela de Ingenieria Geologica y de Minas) 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.)

One of the crucial projects underway in Egypt is the lining of watercourses to withstand the outflow of water through their beds and flanks. Various materials have been used in this project, including limestone, sandstone, basalt, and dolomite, along with other building materials. This study focused on the evaluation of rock characteristics to determine their suitability for the construction of a canal lining. All rock characteristics should be classified in terms of technical and economic concerns related to mining rock specifications, such as mechanical and physical properties, and evaluated according to their weights and ratings. As a rule of decision making, management stakeholders select the rock types. The primary purpose of canal linings is to reduce water loss due to seepage. Methodologically, we adopted the technique for order of preference by similarity to ideal solution (TOPSIS), and derived an improved TOPSIS method based on experimental testing. This study attempted the first application of TOPSIS to canal linings and relevant construction materials. The analysis shows that limestone L1 is the best rock-building material for canal linings in Upper Egypt. Limestone L1 has the shortest geometric distance from the positive ideal solution and the longest geometric distance from the negative ideal solution. The results provide decision makers with strategic indicators to select among different rock types based on the total points assigned to all rock specifications. [ABSTRACT FROM AUTHOR]

The Bahariya Formation (Upper Cretaceous) hosts the most prospective hydrocarbon reservoirs in the Western Desert, Egypt. The reservoir intervals consist mainly of fluvial and coastal marine sandstones, respectively, in the lower and upper Bahariya Formation. The definition of the best reservoir facies and the extent of reservoir heterogeneity are not very well constrained. This study presents a high-resolution definition for the reservoir facies distribution and heterogeneity in Salam Oil Field, north Western Desert. Seismic, well logs, and core analyses have been integrated in order to identify and categorize the different reservoir intervals. Detailed petrophysical well log and core studies have been utilized to further enhance our understanding of the magnitude of heterogeneity within the Bahariya sediments and therefore aid in constructing predictive models, which describe the fluid flow efficiency and reservoir performance. Four petrophysical rock types (PRT) have been identified; PRTI and PRT2 host the optimum reservoir properties and comprises the braided fluvial quartzose sandstones of the lower Bahariya (Av. phi = 20.74%, Av. KH = 367.53 mD, KV = 176.73 mD) with abundant megapores and isotropic, well-connected pore system. The upper Bahariya sediments only constitute the clay-and carbonate-rich PRT3 and PRT4 sediments that are dominated by micropores with predominant mesopores and a heterogeneous, poorly connected pore system. Upper Bahariya sediments have anisotropic pore-system (Av. permeability anisotropy > 3), reflecting the dominant anisotropic pore system. Eight hydraulic flow units (HFU) were identified; the reservoir efficiency decreases from HFU1 to HFU8. At megascale, the main flow conduits (speed zones) are predominantly composed of braided fluvial channel sandstones that mostly contain HFU1 and HFU2. The barrier zones are often associated with HFU7 and HFU8 and are commonly correlated with the lower Bahariya floodplain sediments and tidal flat, mixed tidal flat sediments of upper Bahariya. Notably, the greatest thickness of the upper Bahariya is classified as fluid flow baffles containing HFU5 and HFU6 with abundant micropores with good storage but low flow capacity. [ABSTRACT FROM AUTHOR]

Due to the complicated lithology in the ES3 Member of the Shahejie Formation in the Shulu sag, Jizhong depression, it is difficult to classify the rock types and characterize the reservoirs at the marl intervals. In this paper, a four-element classification method has been proposed, and seven rock types have been identified by analyzing the mineral composition. The primary rock types are medium-high organic carbonate rocks and medium-high organic shaly-siliceous carbonate rocks. With the methods of field emission scanning electron microscopy, high-pressure mercury intrusion, nitrogen adsorption, and nano-CT, four types of reservoir spaces have been identified, including intra-granular pores, intergranular pores (inter-crystalline pores), organic pores, and micro-fractures. By combining the method of high-pressure mercury intrusion with the method of the nitrogen adsorption, the porosity of the marl has been measured, ranging from 0.73% to 5.39%. The distribution of the pore sizes is bimodal, and the pore types are dominated by micron pores. Through this study, it has been concluded that the sag area to the east of Well ST1H is the favorable area for the development of self-sourced and self-reservoired shale oil. According to the results of geochemical and reservoir analysis, the III Oil Group may have sweet spot layers. [ABSTRACT FROM AUTHOR]

Geological storage of CO 2 is a promising technique to mitigate anthropogenic CO 2 emissions. The effectiveness of CO 2 storage in the subsurface formations relies on various trapping mechanisms that immobilize the injected CO 2. Among these mechanisms, residual trapping has been identified as a critical factor, closely associated with residual CO 2 saturation. The extent of residual CO 2 saturation is strongly influenced by the petrophysical, physicochemical and hydrodynamic properties of CO 2 /fluid/rock systems and operational conditions, thereby governing the overall residual trapping efficiency. This article reviews the published experimental datasets on the initial and residual CO 2 saturation and analyzes the corresponding trapping efficiency for a range of in-situ CO 2 /fluid/rock systems. We explore the factors that influence trapping efficiency, including wettability, rock type, rock properties, and flow rate. The gas saturations and trapping efficiencies of different gas types (i.e., CO 2 , N 2 , and H 2) are also discussed. Finally, we present the knowledge gaps and outline prospects for future research. This review establishes a state-of-art data repository of gas saturations in different conditions, enhancing our understanding of residual trapping in subsurface gas storage. [ABSTRACT FROM AUTHOR]

In the mining process of underground metal mines, the misjudgment of rock types by on-site technicians will have a serious negative impact on the stability evaluation of rock mass and the formulation of support schemes, which will result in the loss of economic benefits and potential safety hazards of mining enterprises. In order to realize the precise and intelligent identification of rock types, the image data of peridotite, basalt, marble, gneiss, conglomerate, limestone, granite, magnetite quartzite are amplified. Under the target detection framework of Faster R-CNN deep learning, the extraction network based on simplified VGG16 is used to extract and learn features of rock images, and finally the rock type identification system is successfully trained. The experimental verification shows that the system is correct for single-type rock image recognition and the accuracy is more than 96%. In order to realize accurate and intelligent identification of the surrounding rock surface under complex lithological conditions, the multi-type rocks hybrid images are also identified. The results show that the recognition effect is great and the accuracy rate is over 80%. Therefore, this system can accurately identify rock types with similar image features, which proves that the model has strong robustness and generalization ability. It has broad application prospects in rock mass stability evaluation and rock classification in underground mining.

ABSTRACT: A recent study suggests that the deep dolomites in well Xike-1 located more than 1000 m deep have a very low porosity, and no permeability for most of the samples. Given that the largest oil and gas fields in the South China Sea are all composed of biohermal dolomites while the deep dolomites of Xike-1 serve as the caprock formations rather than the reservoirs, this represents the first discovery and is of great theoretical importance. In this paper, core photos of the tight dolomites are presented. Hand specimens description and systematic porosity-permeability reveal a very low porosity, and no permeability for most of the samples. PLM, SEM and XRPD analysis discovered that the dolostones in the deep tight dolomites are quite large in size and euhedral or subhedral in shape. Alizarin red-stained sections are mostly pink in color and have a full coverage, which are considered as evidence for multiple calcite intrusions after the formation of ankerite dolomites. Biological relict textures are developed. The order degree is medium to low. The dolomites could be the product of penecontemporaneous dolomitization.

Abstract The bedrock of Skåne, the southernmost province of Sweden, has been targeted for geothermal feasibility studies since the late 1970s. An exploration project concerning the geothermal potential in the Romeleåsen Fault Zone was launched outside the town of Lund in 2001. Besides geophysical imaging of the thrust fault zone, the investigations included drilling and investigations of a 3701.8-m-deep exploration well, DGE-1, with the aim to find > 100 °C warm and hydraulically conductive fractured crystalline bedrock associated to the fault zone. The well penetrates a heavily thrusted and predominantly strongly inclined sedimentary succession in hanging rock blocks along the main fault before entering the fractured crystalline basement at 1946 m, primarily composed of gneiss, granite, and metabasite. This paper represents the first comprehensive description and evaluation of the geological, physical, and hydrological properties of the bedrock at these depths in the Romeleåsen Fault Zone coupled to a geothermal assessment. In addition, the applicability of the four drilling methods used in the crystalline basement section is discussed. The outcome of the DGE-1 well shows significant fracturing in the crystalline bedrock at target depth. The investigations show an average thermal gradient of 22 °C/km, an average heat flow of 58 mW/m2, and an average heat production of 5.8 µW/m3. The values are relatively high in comparison to thermal conditions noted in other deep wells in the Fennoscandian Shield. However, a bottomhole temperature of around 85 °C and insufficient fluid production rate made a commercial geothermal system unviable. Despite this, the experiences from drilling and investigations of the crystalline bedrock at several kilometers depth constitute important proxies for assessing the geothermal potential in similar geological settings and for engineered geothermal systems in the crystalline bedrock of south Sweden.

Featured Application: The present work is conducive to focused use of the Brazilian test to obtain the tensile strength and other information of a rock specimen. The fracture behavior of the disc specimens in the Brazilian test is closely related to the reliability and accuracy of the experimental results. To comprehensively investigate the effect of various loading methods and rock material types on the failure mechanism of the Brazilian discs, five different rock types tested with three typical loading methods were employed in this work. The digital image correlation (DIC) method was applied to record and analyze the strain and displacement field of the specimens during the loading process. Experimental results indicate that the peak load and deformation characteristics of the Brazilian discs are strongly affected by the loading types. The Brazilian test with the Chinese standard is evidently not suitable for measuring the tensile strength of rocks, and the other two testing methods may lead to an invalid failure mode for rock materials with high stiffness and tensile to compressive strength ratio. Furthermore, it revealed that the maximum equivalent stress point of a disc specimen is co-controlled by the material stiffness and its tensile–compression ratio. The present work shows that it is necessary to select a suitable loading configuration for each rock type in the Brazilian test. [ABSTRACT FROM AUTHOR]

One of the crucial projects underway in Egypt is the lining of watercourses to withstand the outflow of water through their beds and flanks. Various materials have been used in this project, including limestone, sandstone, basalt, and dolomite, along with other building materials. This study focused on the evaluation of rock characteristics to determine their suitability for the construction of a canal lining. All rock characteristics should be classified in terms of technical and economic concerns related to mining rock specifications, such as mechanical and physical properties, and evaluated according to their weights and ratings. As a rule of decision making, management stakeholders select the rock types. The primary purpose of canal linings is to reduce water loss due to seepage. Methodologically, we adopted the technique for order of preference by similarity to ideal solution (TOPSIS), and derived an improved TOPSIS method based on experimental testing. This study attempted the first application of TOPSIS to canal linings and relevant construction materials. The analysis shows that limestone L1 is the best rock-building material for canal linings in Upper Egypt. Limestone L1 has the shortest geometric distance from the positive ideal solution and the longest geometric distance from the negative ideal solution. The results provide decision makers with strategic indicators to select among different rock types based on the total points assigned to all rock specifications.

For the construction of the Brenner Base Tunnel with a total length of the whole tunnel system of 230 km, the geotechnical characterisation of the rock and the rock mass based on the geological mapping, the exploration and the geological models is of essential importance. The reliability of the ground prediction and consequently the effectiveness of the construction and support measures are mainly influenced by the methodology for the evaluation of the characteristic material parameters of the ground. This mainly influences the project process and the construction as well as the maintenance costs of a tunnelling project. In this paper, the applied methodology with its approaches of resolution for the improvement of the reliability of the ground prediction at the Brenner Base Tunnel project are explained in detail. Furthermore the improvements to this methodology during different project stages are shown. The paper concentrates on the implementation of the results gained from the exploratory tunnel and the influence of these results on the methodology for the improvement of ground prediction and the reduction of ground risks. In addition problems and approaches for solving these problems are explained in detail. For instance the avoidance of the double consideration of the influence of schistosity by using a rock mass classification system for rock mass parameter identification. [ABSTRACT FROM AUTHOR]

Organic reefs are favourable accumulation spaces for hydrocarbons and various mineral resources. A complete Permian organic reef profile about 44 m thick with distribution area no more than 1 km2 is exposed near Lengwu, Tonglu, Zhejiang Province. Examination of outcrops and thin sections revealed that the main reef-building organisms are calcisponges, with inozoans as dominant type. Five types of rocks have been recognized in the reef, and they are calcisponge framestone, calcisponge bafflestone, bindstone, rudstone and bioclastic wackestone. The profile was constructed in three reef-building stages. The thickness of the second stage is largest, followed by the first stage and the third stage is smallest. Each stage started with a framestone or bafflestone, ended as the reef grew near the sea-level, and died because of influx of terrigenous sediments. The development of the Lengwu reef is controlled by biological factors and sea-level changes. Based on the study a reef sedimentary model is established.

The fracture behavior of the disc specimens in the Brazilian test is closely related to the reliability and accuracy of the experimental results. To comprehensively investigate the effect of various loading methods and rock material types on the failure mechanism of the Brazilian discs, five different rock types tested with three typical loading methods were employed in this work. The digital image correlation (DIC) method was applied to record and analyze the strain and displacement field of the specimens during the loading process. Experimental results indicate that the peak load and deformation characteristics of the Brazilian discs are strongly affected by the loading types. The Brazilian test with the Chinese standard is evidently not suitable for measuring the tensile strength of rocks, and the other two testing methods may lead to an invalid failure mode for rock materials with high stiffness and tensile to compressive strength ratio. Furthermore, it revealed that the maximum equivalent stress point of a disc specimen is co-controlled by the material stiffness and its tensile–compression ratio. The present work shows that it is necessary to select a suitable loading configuration for each rock type in the Brazilian test.

The main purpose of this investigation is to study the effect of near miscible CO2 injection in different porous mediums on both lab and field scales. This effect can be traced by the change of two-phase gas-oil relative permeability curves. In this work, the experiments have been performed on three rock types (i.e. sandstone, dolomite, and artificial fractured sandstone) based on an incremental pressure algorithm approaching a near miscible condition. Lab-scale inverse modeling has been used to calculate relative permeability curves. Based on the experimental results, 85%of minimum miscibility pressure was defined as the near miscible pressure. Comprising the relative permeability curves in immiscible and near-miscible conditions, the results show that this change has become less significant from sandstone core type to artificial fractured. In other words, near miscible CO2 injection would be recommended in rock types with a lower RQI. In addition, it was concluded that in the case of artificial fractured, simple conventional relative permeability methods obtain the same results as sophisticated inverse modeling method. Furthermore, in order to validate the lab scale results, the field scale modeling of the candidate reservoir was done using the 3D compositional reservoir simulator. 83% of minimum miscibility pressure was defined as near miscible pressure. Moreover, the simulation results confirmed lab-scale data regarding the recovery factor in different rock types. Additionally, the economic evaluation (NPV analysis) showed that use of near miscible CO2 injection in lower RQI reservoirs was more economical rather than the other scenarios.

Modeling and classification of the subsurface lithology is very important to understand the evolution of the earth system. However, precise classification and mapping of lithology using a single framework are difficult due to the complexity and the nonlinearity of the problem driven by limited core sample information. Here, we implement a joint approach by combining the unsupervised and the supervised methods in a single framework for better classification and mapping of rock types. In the unsupervised method, we use the principal component analysis (PCA), K-means cluster analysis (K-means), dendrogram analysis, Fuzzy C-means (FCM) cluster analysis and self-organizing map (SOM). In the supervised method, we use the Bayesian neural networks (BNN) optimized by the Hybrid Monte Carlo (HMC) (BNN-HMC) and the scaled conjugate gradient (SCG) (BNN-SCG) techniques. We use P-wave velocity, density, neutron porosity, resistivity and gamma ray logs of the well U1343E of the Integrated Ocean Drilling Program (IODP) Expedition 323 in the Bering Sea slope region. While the SOM algorithm allows us to visualize the clustering results in spatial domain, the combined classification schemes (supervised and unsupervised) uncover the different patterns of lithology such of as clayey-silt, diatom-silt and silty-clay from an un-cored section of the drilled hole. In addition, the BNN approach is capable of estimating uncertainty in the predictive modeling of three types of rocks over the entire lithology section at site U1343. Alternate succession of clayey-silt, diatom-silt and silty-clay may be representative of crustal inhomogeneity in general and thus could be a basis for detail study related to the productivity of methane gas in the oceans worldwide. Moreover, at the 530 m depth down below seafloor (DSF), the transition from Pliocene to Pleistocene could be linked to lithological alternation between the clayey-silt and the diatom-silt. The present results could provide the basis for the detailed study to get deeper insight into the Bering Sea’ sediment deposition and sequence. [ABSTRACT FROM AUTHOR]