期刊,Journal of Petroleum Science & Engineering 2022年208PA卷期_国家学术搜索

期刊信息/Journal information

Journal of Petroleum Science & Engineering

Elsevier Science B.V.

主办单位：Elsevier Science B.V.

国际刊号：0920-4105

Journal of Petroleum Science & Engineering/Journal Journal of Petroleum Science & Engineering

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An integrated fracture parameter prediction and characterization method in deeply-buried carbonate reservoirs based on deep neural network

Qamar YasinYan DingSyrine Baklouti

21页

查看更多>>摘要：Deeply buried fractured reservoirs have evolved into significant oil and gas potential in many basins of the world. However, fracture prediction in deeply buried carbonate reservoirs has always been challenging. Fracture prediction in the deep-buried carbonate structure of North China is problematic because of multiphase tectonic movements, variable sediment lithology, and complex diagenesis. Because of deep burial depth and complex heterogeneity, the resolution of seismic reflection data beneath the buried-structure is poor, making it challenging to identify the fault reflection characteristics. This paper proposes a novel idea to identify natural fractures in carbonate reservoirs using conventional logs with seismic reflection data. The proposed model can also predict the fracture aperture and fracture density, a distinctive feature. Another novel hybrid model based on deep-learning neural network (DNN) and cluster analysis is proposed to predict further the spatial variations of lithology, porosity, and fracture parameters from seismic inversion. The proposed models provide valuable insights that help determine fracture parameters in the Paleozoic strata and associated reservoirs through quantitative analysis using petrophysics, rock physics, seismic inversion, and seismic attributes. The overlapping of seismic interpreted fault networks and spatial variations of the inverted fracture parameters indicate a high correlation of fracture development zones. The methodology proposed in this study presents a valuable template valid for the characterization of fractured reservoirs in deeply-buried carbonate reservoirs throughout the world.

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Integrated sedimentary and high-resolution mineralogical characterisation of Ordovician shale from Canning Basin, Western Australia;; Implications for facies heterogeneity evaluation

Muhammad Atif IqbalReza RezaeeCarsten Laukamp

24页

查看更多>>摘要：An understanding of the nature of the facies heterogeneity is crucial for successful exploration and development of shale reservoirs. However, shale is a very fine-grained sedimentary rock and it is challenging to understand its heterogeneity through conventional techniques. This paper addresses this challenge for Ordovician Goldwyer Formation (Goldwyer-III shale) through a unique approach by integrating core data with high-re solution image logs (SCMI);; petrographic information;; Fourier transform infrared (FTIR);; and hyperspectral drill core reflectance spectra acquired using a HyLogger3. The petrographic and FTIR data validates the usage of HyLogger3 as a tool to examine high-resolution vertical variations in the shale mineralogy. The results indicate that the Goldwyer-III shale is highly heterogeneous in terms of sedimentary features, organic richness and mineral composition. The studied shale is divided into four facies based on colour, sedimentary features, mineral composition and lithology. The facies include thinly laminated siliceous shale (TLSh), concretionary-banded calcareous shale (CSh), massive black shale (MBSh) and heterolithic shale (HSh). The total organic carbon varies from 0.35 to 4.5 wt% due to variation in facies as a result of fluctuation in oxic-anoxic conditions. The TLSh, MBSh and HSh facies have a higher TOC value (up to 4.5 wt %), T_(max) (up to 450 °C), hydrogen index (up to 250 mgHC/g) and brittleness index (>0.4) comparatively. Whereas, the CSh facies has least TOC, Tmax, hydrogen index and brittleness index. Continuous high-resolution hyperspectral core log data, combined with petrography and conventional core logging, provides a much better understanding of heterogeneity in Goldwyer-III shale. This study offers a new workflow for rapid, continuous and accurate recognition of optimum facies for hydraulic fracturing. This approach can improve economic decisions when developing shale gas reservoirs. Based on TOC and mineralogical derived brittleness index cut-offs values, the high-quality brittle zones are recognised in TLSh and HSh facies deposited in medial (proximal to distal) depositional setting.

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Effects of dolomitization on porosity-Permeability distribution in depositional sequences and its effects on reservoir quality, a case from Asmari Formation, SW Iran

Asadollah MahboubiReza Moussavi-HaramiArmin Omidpour

25页

查看更多>>摘要：The Oligocene-Miocene Asmari reservoir is dominated by heterogeneity in various aspects, especially porosity and permeability caused mainly by dolomitization. The consequences of petrographic studies of core samples from five cored wells lead to four depositional environments to be identified;; inner ramp, mid ramp, outer ramp and basin. This succession is arranged in six third-order depositional sequences. The formation has undergone complex diagenetic alteration represented mainly by multiple generations of dolomites. Dolomite types comprise (i) very finely-crystalline, fabric-retentive dolomite (Dl), (ii) fine to medium-crystalline, fabric-retentive dolomite (D2);; (iii) medium to coarse-crystalline, fabric-destructive dolomite (D3);; and (iv) very coarsely-crystalline, non-planar saddle dolomite (D4). Dl substituted by micritic matrix in mud-supported facies before early compaction. D2 and D3 were formed by the reflux of warmer and more saline fluids during intermediate burial, and also by the recrystallization of Dl. D4 was precipitated from hot, saline fluids during deep burial. Fine-to medium-crystalline, fabric-retentive dolomites occur in the upper part of the formation, whereas coarse-crystalline fabric-destructive dolomites mostly occur in the middle and lower parts. This causes distribution of porosity and permeability in the depositional sequences, thereby affecting the reservoir quality. Accordingly, dolomitization resulted in enhanced porosity and permeability and improved reservoir quality.

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Gas channels and chimneys prediction using artificial neural networks and multi-seismic attributes, offshore West Nile Delta, Egypt

Amir IsmailHatem Farouk EwidaSahar Nazeri

16页

查看更多>>摘要：Machine learning techniques combined with multi-seismic attributes and well logs datasets have been successfully used in reducing the risk of drilling operations and petroleum exploration by providing precise petrophysical and seismic information extracted from the hydrocarbon reservoir rocks. For this purpose, Artificial Neural Networks (ANNs) work as a multi-channel processing system with a high degree of interconnection to classify various faces and predict the reservoir properties through the seismic profile by involving multi-seismic attributes and optionally well logs to the inputs. The main aim of this study is to use both supervised and unsupervised neural networks for the first time in the West Delta Deep Marine (WDDM) concession to identify the spatial dimensions of the gas-bearing channels and the detection of gas chimneys across the seismic profiles. We use back-error propagation algorithms of the Multilayer Perceptron (MLP) and self-organizing Unsupervised Vector Quantizer (UVQ) as supervised and unsupervised neural network methods, respectively, to detect the gas zones and channels, and to classify the gas chimneys and non-gas chimneys zones, as well as classification of the seismic reflections and lithologies. The output acquires a detailed analysis of the distribution pattern of gas channels and accurate information to image the gas chimneys. In the current study, the approach adopted is beneficial to image the gas chimneys and channels in different basins in any region of the world with similar geological settings.

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Effect of paleoclimate and paleoenvironment on organic matter accumulation in lacustrine shale: Constraints from lithofacies and element geochemistry in the northern Qaidam Basin, NW China

Longyi ShaoYonghong LiHaihai Hou

16页

查看更多>>摘要：Organic matter enrichment in lacustrine shale is significantly influenced by paleodimate and paleoenvironment. In this study, a total of 24 shale samples were vertically collected from the YQ~(-1) drilling well in the northern Qaidam Basin, north-western China. The high-resolution geochemistry analyses were performed to provide a detailed geological description of these samples through lithofacies interpretation, total organic carbon (TOC) content testing, element geochemistry analysis, and mineralogical composition characterization. The results show that four lithofacies types can be identified in the Middle Jurassic Shimengou Formation, which consist of the brown oil shale with horizontal bedding, the black shale with well-developed lamination, the grey-black mudstone with horizontal and wavy bedding, and the carbonaceous mudstone with plant debris. The former two types were preserved in the Upper Member and were mainly deposited in a deep and semi-deep lake environment, whereas the latter two types were preserved in the Lower Member and were deposited in a littoral-shallow lake. The TOC content, paleo-salinity, redox action, and paleo-productivity of the shales in the Upper Member are higher than those in the Lower Member, and other parameters, such as the chemical weathering degree and terrestrial clastic input, are higher in the shales of the Lower Member. Based on lithofacies and geochemical data, the shales in the Lower Member were deposited in a small, shallow freshwater lake within an oxygen-rich and relatively wet and hot paleoclimate, whereas the shales in the Upper Member were deposited in a large, deep, and saline water lake with dysoxic-anoxic conditions and a relatively arid and cold paleoclimate. The organic matter content in the Lower Member was primarily determined by the amount of detritus input with a low paleo-productivity owing to a strong weathering, whereas that in the Upper Member was dominated by anoxic processes under a good preservation and a low deposition rate. The model reflecting the relationship between accommodation and sediment-fill is employed to analyse the mechanism of organic matter accumulation. Three depositional stages are distinguished within the Shimengou Formation corresponding to overfilled, underfilled, and balanced-filled sediments with average TOC contents of 0.84 %, 4.95 %, and 6.09 %, respectively. This study reveals the dominated factors controlling organic matter enrichment in a continental basin and proposes a TOC distribution mechanism, which could provide a guide for the shale gas and shale oil exploration.

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Study on the pore structure, fluid mobility, and oiliness of the lacustrine organic-rich shale affected by volcanic ash from the Permian Lucaogou Formation in the Santanghu Basin, Northwest China

Yongshuai PanZhilong HuangXiaobo Guo

19页

查看更多>>摘要：Lacustrine organic-rich shale with extremely heterogeneous pore structure is widespread in the second member of the Permian Lucaogou Formation (P2I2) of the Santanghu Basin. However, information on the pore structure, fluid mobility, and oiliness characteristics is still lacking, as well as the interaction between them in the organic-rich shales remains controversial. To address these problems, this study analyzed the influencing factors of pore structure, oiliness, and fluid mobility of the P2I2 shale and constrained the lower limit of movable fluid pore throat radius based on thin sections, routine core analysis, whole rock X-ray diffraction (XRD), scanning electron microscopy (SEM), high-pressure mercury injection (HPMI), nuclear magnetic resonance (NMR), constant-rate mercury injection (CMI), and nano-CT scanning data. The P2I2 shale was characterized by fine-grained minerals of felsic (tufFaceous material) and carbonate (dolomite), with poor reservoir physical properties and strong oil-bearing heterogeneity. Micro-and nano-scale pores are the main type of storage space. Among them, most of the microfractures emit green to yellow hydrocarbon fluorescence regardless of whether they are filled or not, as do the edges of dolomite grains. While the edges of the felsic minerals are characterized by stronger orange yellow fluorescence of organic matter. According to the morphology and parameters of HPMI and NMR curves, the pore structure can be divided into four types. From type 1 to type 4 pore structure, the maximum mercury saturation decreases from 95 to 47 % (avg. 70 %), indicating poor pore connectivity, and the pore throat radius that mainly contributes to permeability is > 0.04 jim. Meantime, the NMR T2 spectrum gradually transitions from right unimodal to left unimodal behavior, with a gradual decrease in the saturation of movable fluid and a transition of the mineral type from carbonate to felsic. Fluid mobility is not only influenced by macropores, but also related to the content of small pores (T2 < 1 ms) and the mineral type. On this basis, the lower limit of the movable fluid pore throat radius in the P2I2 organic-rich shale is finally determined to be 40 nm.

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Discussion of seismic diagenetic facies of deep reservoir in the East China Sea Basin

Wenguang WangChengyan LinXianguo Zhang

13页

查看更多>>摘要：Evaluation of seismic diagenetic facies is an effective interpretation procedure to characterize the spatial distribution of diagenetic facies in deep tight sandstones in offshore sparse well areas. Based on petrographic and seismic data, research on seismic diagenetic facies was used in the proposed workflow to predict the spatial distribution and distribution characteristics of seismic diagenetic facies for the third (H4c) sub-member of the fourth (H4) member of the E3I1 Formation in the Xihu Sag, East China Sea Basin, Eastern China. Herein, two discriminant functions between the core-derived diagenetic facies and the seismic elastic parameters of shear modulus, p-wave impedance, and porosity data volume were established using the supervised learning method, and seismic data X and seismic data Y containing diagenetic facies information were evaluated. Based on the linear function between seismic data X and seismic data Y, a new seismic data volume was calculated and a comprehensive index of diagenetic facies was proposed to describe the distribution of diagenetic facies. The comprehensive index of diagenetic facies can better identify the spatial distribution of diagenetic facies. The results of seismic diagenetic facies research mainly focused on (1) the spatial distribution of diagenetic facies and (2) the distribution characteristics of diagenetic facies. Based on core-derived diagenetic facies, typical stratal slices, and sedimentary microfacies, the spatial distribution of seismic diagenetic facies in the two sublayers of the H4c sandstone was accurately interpreted. The northern part of the H4cl and H4c2 sublayers mainly developed quartz-cemented facies and a small amount of chlorite-coated quartz facies. The southern part and the surrounding areas of the H4cl and H4c2 sublayers primarily developed tightly compacted facies. The area near four (Fl, F2, F3, and F4) faults in the H4cl sublayer mainly developed a small amount of dissolution facies, whereas the area near the F2 and F4 faults in the H4c2 sublayer primarily developed a small amount of dissolution facies. Furthermore, the distribution characteristics of seismic diagenetic facies were investigated from the perspective of sedimentary microfacies and diagenetic facies. The chlorite-coated facies is mainly distributed in the subaqueous distributary channel sedimentary microfacies. The dissolution facies is primarily distributed in the subaqueous distributary channel and sheet sand sedimentary microfacies near the faults. This study shows that the research of seismic diagenetic facies using petrographic data and seismic data can better predict the spatial distribution of diagenetic facies of deep tight sandstone.

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Tectono-thermal impacts on the formation of a heavy oil in the eastern Tarim Basin (China): Implications for oil and gas potential

Zhiyao ZhangGuangyou ZhuJianfa Han

11页

查看更多>>摘要：Unraveling the accumulation and alteration process of reservoired petroleum is significant for the evaluation of petroleum potential. In this study, a paleo heavy oil from the TD2 well in the eastern Tarim Basin was investigated through integrated geochemical methods including two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC x GC-TOFMS), gas chromatography-mass spectrometry (GC-MS) and compound specific carbon isotope analysis (CSCIA). Oil-source correlation analysis indicates that the TD2 oil accumulation is "self-generation and self-accumulation" within the Cambrian strata. Combined with tectonic evolution analysis, it is suggested that the oil experienced significant impacts due to changes in tectono-thermal process. Abnormally enriched polycyclic aromatic hydrocarbons (62.5 mg/g in total, 4-to 6-ring account for-41 %) with few substituents suggest oil cracking due to a short-time high-temperature heating during rapid tectonic subsidence under higher geothermal gradient. Phase fractionation, as indicated by the physiochemical features and heavy isotopic values, was induced by severe tectonic uplift and denudation after accumulation, and resulted in the thickening, redistribution, and destruction of the primary oil pool. After that, the TD2 oil pool was preserved from further alterations under steady tectonic setting with a low geothermal gradient. Four accumulation assemblages in the eastern Tarim Basin were identified and compared, indicating that great oil and gas potential remains including oil/heavy oil in the Cambrian assemblage and light oil/condensate in the Jurassic and Silurian assemblages. Future exploration should focus on locally developed favorable reservoirs with good preservation conditions.

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A framework to obtain the formulas of the conductivity and aperture of rough fractures under thermohydromechanical conditions

Shiming WeiYan JinShiguo Wang

14页

查看更多>>摘要：In this investigation, a framework is proposed to find the equations to describe the fracture conductivity and fracture aperture as the functions of effective stress (the difference between geo-stress and fluid pressure), temperature difference (the difference between rock temperature and fluid temperature), and the rock mechanical properties. The framework consists of several lab experiments and a numerical model, which is time-saving to study the influences of the aforementioned influential factors on the fracture conductivity and aperture. After analyzing the lab experimental data, we find that it's almost impossible to accurately measure the fracture aperture even with high-precision displacement sensors. Therefore, the numerical model coupling the fluid flow in the rough fracture, the solid deformation, and the heat transfer between the hot rock and the injected fluid is built. Three different distributions of the fracture surfaces are analyzed, and we find that the fracture surface roughness fits the normal distribution. After the data matching between the lab experimental data and the numerical results, a large number of numerical experiments using the numerical model are carried out to study the influences of the effective stress, temperature difference and the rock properties, including the elasticity and Poisson's ratio. When fitting the single variable analysis results, we find that the fracture conductivity and aperture are in different function forms of the aforementioned factors. But the reduction of fracture aperture and the natural logarithm of the normalized fracture conductivity can be described using the binary linear function of the effective stress and the temperature difference. Two key strengths of the research lie with the fact that it is time-saving to obtain the exact formulas of fracture conductivity and fracture aperture, and it can measure the dynamic fracture aperture accurately.

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Influence of rock fabric on salt ion diffusion behavior in upper cretaceous lacustrine shale from Songliao Basin

Mianmo MengHongkui GeYinghao Shen

11页

查看更多>>摘要：Some shale reservoirs have high salt ion concentration in flow-back fluid, about which the mechanism is still unclear. To learn the rock fabric of lacustrine shale and its influence on the salt ion diffusion behavior, the investigation of rock component, pore structure, spontaneous imbibition and salt ion diffusion were conducted. Rock component includes inorganic minerals and organic matter. Pore structure includes overburden porosity-permeability, scanning electron microscope (SEM), nitrogen adsorption (NA), mercury intrusion porosimetry (MIP). Comparing the pore size distribution between NA and MIP, lots of pores are connected by small throat, and the pore volume controlled by throat can be 18 times of throat volume. Based on fractal dimensions analysis, which was defined by using the fractal Frenkel-Halsey-Hill (FHH) method based on NA, lacustrine shale has a smoother pore surface and a complex pore structure. The fractal dimensions are mainly controlled by specific surface area. Imbibition liquid is a medium for salt ion diffusing out of matrix and the salt ion diffuse nearly linearly with time in log scale after imbibition becomes stable. The slope of fitting line by using late diffusion data is defined as salt ion diffusion rate. The salt ion diffusion rate is mainly controlled by clay content, TOC, pore volume and specific surface area. The interaction between clay and liquid has the potential to release lots of salt ion, and a higher specific surface area provide more area for liquid interaction with minerals, and a higher pore volume provide more channel for salt ion diffusing out of sample. Our research is conducive to understanding the rock fabric of lacustrine shale in Qingshankou Formation and its influence on salt ion diffusion behavior.

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