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01 April 2023, Volume 44 Issue 2 Previous Issue    Next Issue

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OIL AND GAS EXPLORATION

Deformation and Favorable Area Evaluation of Shunbei No.4 Strike-Slip Fault Zone in Tarim Basin LI Haiying, HAN Jun, CHEN Ping, LI Yuan, BU Xuqiang 2023, 44 (2):  127-135.  doi: 10.7657/XJPG20230201 Abstract ( 341 )   HTML ( 39 )   PDF (7486KB) ( 240 )   Save The Shunbei No. 4 strike-slip fault zone which is located in the Shuntuoguole low uplift of the Tarim basin and extends northward to the Shaya uplift is characterized by deep burial，horizontal segmentation，vertical stratification，multi-stage activities，and complex structure. Through the interpretation of high-quality 3D seismic data from the Shunbei No. 4 strike-slip fault zone，the stratification，segmentation，staging，activity and favorable area evaluation of the fault zone were carried out. The results show that the Shunbei No. 4 strike-slip fault zone has a 4-layer structure in the Paleozoic，roughly bounded by the top of the Middle Ordovician，above which echelon faults are found and below which high-steep strike-slip faults are developed. The strike-slip fault zone is visibly segmented into the northern segment，the middle segment，and the southern segment according to the strike，showing an overall characteristic of compressed in south and extended in north. In the Paleozoic，the strike-slip fault zone successively experienced four periods of activity，namely，EpisodeⅠof the middle Caledonian，Episode Ⅲ of the middle Caledonian，late Caledonian，and Hercynian. By combining the main controlling factors (e.g. source-reservoir connectivity，reservoir size，and late adjustment) for hydrocarbon enrichment and accumulation in the Shunbei area，the favorable areas in the Shunbei No. 4 strike-slip fault zone were evaluated. Multiple favorable areas have been identified and then verified by actual drilling. Figures and Tables | References | Related Articles | Metrics

Characteristics and Identification of Zeolite-Bearing Tight Sandy Conglomerate Reservoirs in Wuerhe Formation，Mahu Sag QIN Zhijun, CAO Yingchang, MAO Rui, ZHANG Hao, FENG Cheng 2023, 44 (2):  136-143.  doi: 10.7657/XJPG20230202 Abstract ( 263 )   HTML ( 22 )   PDF (5390KB) ( 140 )   Save Zeolite is found in the tight sandy conglomerate reservoirs of the Permian Wuerhe formation in the Mahu sag, Junggar basin, leading to great difficulties in oil-bearing property evaluation and productivity estimation for the tight sandy conglomerate reservoirs due to their abnormal reservoir physical properties. The experiments by using casting thin sections and scanning electron microscope were carried out to analyze the geological characteristics of zeolite, including the occurrence, symbiotic relationship with other minerals, and diagenetic sequence of zeolite cement. Through the analysis of core and logging data, it is clear that the zeolite-bearing tight sandy conglomerate reservoirs show the logging responses featured with low density, high neutron porosity and high acoustic slowness. By intersecting the difference between neutron logging porosity and density logging porosity with the difference between neutron logging porosity and acoustic slowness porosity, the chart for identifying the sandy conglomerate reservoirs containing zeolites was established. Based on the normalized tri-porosity logging parameters, a model for quantitatively predicting zeolite content was built. By comparing the zeolite content from core analysis with the content predicted by the model, it is confirmed that the prediction accuracy of the model is high. Based on the identification results of the zeolite-bearing tight sandy conglomerate reservoirs in 132 wells, the development zones of tight sandy conglomerate reservoirs containing zeolites in the Wuerhe formation in the study area were determined. The dissolution of zeolites can create a lot of accommodations for hydrocarbon accumulation. The study results provide reliable guidance for predicting favorable areas of tight sandy conglomerate reservoirs in the study area. Figures and Tables | References | Related Articles | Metrics

Spatial Distribution of Architectures of Braided River Reservoirs in He 8 Member, Sulige Gas Field LIU Jinku, HU Yang, WU Yi 2023, 44 (2):  144-150.  doi: 10.7657/XJPG20230203 Abstract ( 241 )   HTML ( 21 )   PDF (4557KB) ( 153 )   Save In order to determine the spatial distribution of the architectures of the multi-stage superimposed braided-river tight sandstone reservoirs in the He 8 member, Sulige gas field, by using well logging and core data and referring to modern rivers, the architecture division scheme of the braided river reservoirs in the study area was determined, and the reservoir architecture units were dissected hierarchically. Through the joint simulation based on pixel and target methods, a 3D architecture model of the braided river reservoir including multi-level architecture units was established to finely depict the spatial distribution of different reservoir architectures. The reservoirs in the He 8 member formed due to the vertical or lateral cutting and stacking of multi-phase sand bodies of braided channel. The mid-channel bar of a single braided belt appears in form of lens. The interior of mid-channel bar is separated by discontinuous fall-siltseam, and the braided channels are distributed around the mid-channel bar. According to the 3D architecture model, the reservoir can be divided into different hierarchical architectures, among which the favorable reservoir interval is He 84 sublayer which is mainly distributed in two major braided belts extending north-south in the east and west of the study area, and high-quality sand bodies are distributed in a lenticular shape inside the braided belt. The research results were applied to horizontal well deployment and geosteering drilling, and the drilling results show a high coincidence rate with model predictions. Figures and Tables | References | Related Articles | Metrics

Genesis of Low-Resistivity Reservoirs in Sangonghe Formation，Mahu Sag QI Yuan, HAN Dongwei, DU Yinyu, ZHOU Weijun 2023, 44 (2):  151-160.  doi: 10.7657/XJPG20230204 Abstract ( 248 )   HTML ( 18 )   PDF (10593KB) ( 94 )   Save The widespread low-resistivity oil reservoirs in the Jurassic Sangonghe formation on the southern slope of the Mahu sag in the Junggar basin are difficult to identify due to their complex formation mechanisms and unclear oil-water contacts. According to the geological characteristics of these reservoirs, and combined with the data from laboratory analysis, formation test, production test and logging, the genesis of the low-resistivity reservoirs were systematically analyzed. The results show that the reservoirs in the second member of Sangonghe formation (San-2 member) in the study area contain mainly tuff debris and have microfractures and micropores resulted from compaction and dissolution, leading to complex pore structure and high irreducible water saturation. High irreducible water saturation and high formation water salinity are the main geneses of the low-resistivity of the reservoirs in the Sangonghe formation. The reservoir rocks are fine-grained, mainly composed of fine sandstone and siltstone, and contain clay minerals dominated by kaolinite and illite/smectite, which are the secondary genetic factors of low-resistivity reservoirs. The research results have been applied satisfactorily in the identification of reservoirs in the study area, providing a certain theoretical basis for evaluating low-resistivity reservoirs of the Sangonghe formation in the Mahu sag. Figures and Tables | References | Related Articles | Metrics

Characteristics and Genesis of Calcareous Interlayers in Underwater Distributary Channel Sandbodies in Chang 8 Reservoir，Ganquan Oilfield CUI Yaoke, DU Guichao, WANG Fengqin, WANG Cong’e, CHEN Yiyang, WANG Ying, HUANG Xingyu 2023, 44 (2):  161-168.  doi: 10.7657/XJPG20230205 Abstract ( 276 )   HTML ( 23 )   PDF (5199KB) ( 138 )   Save The study on calcareous interlayers is of great significance to well pattern deployment in the early stage of oilfield development and to the increase of reserves and production in the late stage. By means of core observation，well logging data analysis，casting thin section and SEM observation，the lithology，electrical properties，distribution，and genesis of calcareous interlayers in the eighth member of Yanchang formation (Chang 8 member) in the Ganquan oilfield and the influence of such calcareous interlayers on reservoir heterogeneity were systematically studied. The results show that the calcareous interlayers were developed under the control of underwater distributary channel microfacies，mainly at the top and bottom of sand bodies. The calcareous interlayers exhibit the geological characteristics of high stability and large thickness，and the logging response characteristics of low gamma，low acoustic slowness and high resistivity. The development of the calcareous interlayers was mainly controlled by calcite cementation of two periods. The calcite cementation of the first period was related to the supersaturated precipitation of calcite in the syndiagenetic stage，during which the dissolution of crustal biological residues，Ca2+ and $CO_{3}^{2-}$ carried by rivers，and the dissolution of CO2 from the atmosphere provided materials for calcite cementation. The calcite cementation of the second period was the porous cementation in the Phase B of the middle diagenetic stage，and the residual Ca2+ and $CO_{3}^{2-}$ in the original formation fluids，the dissolution of unstable components，and Ca2+ and $CO_{3}^{2-}$ precipitated from mineral transformation provided materials for calcareous cementation. The development of calcareous interlayers enhanced the intralayer heterogeneity of sandbodies，leading to poor vertical sandbody connectivity and complex oil-water relationships. During the water flooding of the reservoir，calcareous interlayers obliquely intersect with the adjacent non-permeable interlayers，forming effective barriers and remaining-oil enriching areas locally. Figures and Tables | References | Related Articles | Metrics

RESERVOIR ENGINEERING

Propagation of Hydraulic Fractures and Fracability Evaluation of Sandy Conglomerate Reservoirs LIU Xiangjun, WANG Xiaojun, ZHAO Baowei, XIONG Jian, LIANG Lixi 2023, 44 (2):  169-177.  doi: 10.7657/XJPG20230206 Abstract ( 240 )   HTML ( 18 )   PDF (8921KB) ( 111 )   Save In order to understand the propagation and extension of hydraulic fractures in the sandy conglomerate reservoirs of Permian Wuerhe formation，Junggar basin，the influences of gravel characteristics，in-situ stress，and other factors on the fracture propagation were studied by using the Realistic Failure Process Analysis (RFPA) software. According to the results of numerical simulation，the fracture propagation process under different conditions was studied，the evolution and shape of the fractures were described，and a model for evaluating the fracabilty of the sandy conglomerate reservoirs was established. The results show that the gravel strength and matrix strength of Wuerhe formation are quite different. The gravel strength ranges from 216.62 MPa to 2 032.64 MPa，which is 2-4 times of matrix strength. The rock mechanical properties of conglomerates differ significantly. When gravel content is small，fracture propagation is mainly affected by principal stress. When the grain size of gravel is small，fractures mainly extend bypassing the gravel. With the increase of grain size or gravel content，the inhibition and shielding effects of gravel on fractures become obvious，which reduces the extension of fractures. The greater the difference between gravel strength and matrix strength，the stronger the fractures are blocked by the gravel，and the more easily the fractures extend in the way of bypassing the gravel rather than penetrating the gravel，which reduces the extension of fractures. Based on grey relational analysis (GRA) and analytic hierarchy process (AHP)，a model for calculating the fracabilty evaluation coefficient of the sandy conglomerate reservoirs was established，which considers the factors such as gravel characteristics and horizontal in-situ stress. The fracabilty evaluation coefficient is positively correlated with dimensionless fracture area and fluid production index per meter. Figures and Tables | References | Related Articles | Metrics

Characterization of Hydraulic Fractures in Tight Conglomerate Reservoirs in Baikouquan Formation，Mabei Slope LI Xiangyang, JI Hancheng, BIAN Tengfei, CHEN Liang, CHEN Liang, GUO Xinshu, LI Mengkai 2023, 44 (2):  178-183.  doi: 10.7657/XJPG20230207 Abstract ( 222 )   HTML ( 20 )   PDF (1833KB) ( 131 )   Save Hydraulic fracturing is a main technique for developing oil and gas in tight conglomerate reservoirs. Currently，hydraulic fractures are mainly studied by means of physical experiments and numerical simulation. The study results can provide a theoretical basis for optimization of development plans，but they are not verified with field data，bringing great uncertainties to the design of stimulation measures. In order to describe the shape of hydraulic fractures for confirming the effective stimulation in tight conglomerate reservoirs，a coring well was drilled on the north slope of Mahu sag for obtaining hydraulic fractures. Based on the observation and analysis of the tight conglomerate cores，the shape，occurrence，and density of hydraulic fractures were characterized by using the core，image logging and CT scanning data. It is found that the tight conglomerate is characterized by large grain size，poor sorting，grain support，and strong heterogeneity. A total of 335 hydraulic fractures were identified in the core with the length of 323 m. Principal fractures propagate in the direction perpendicular to the wellbore; branch fractures are few and nearly perpendicular to the main fractures; crushed zones and asymmetrical double-wing fractures are observed in some intervals. The fractures propagate in two modes: gravel bypassing and gravel penetrating，which are formed due to tension and shear action，respectively，and are thus classified as tensional fractures and shear fractures. The tensional fractures and shear fractures are consistent in occurrence，both with a high dip angle close to 90° and a nearly south-north trending. The density of shear fractures is generally greater than that of tensional fractures. Figures and Tables | References | Related Articles | Metrics

Optimization of Key Fracturing Parameters for Profitable Development of Horizontal Wells in Mahu Conglomerate Reservoirs ZHANG Jing, HU Dandan, QIN Jianhua, WANG Yingwei, TANG Huiying 2023, 44 (2):  184-194.  doi: 10.7657/XJPG20230208 Abstract ( 266 )   HTML ( 16 )   PDF (1343KB) ( 129 )   Save In the process of transforming the Mahu conglomerate reservoirs in the Junggar basin from large-scale development to profitable development，it is particularly important to select reasonable fracturing parameters under the premise of considering economic benefits. In order to realize the optimization of key fracturing parameters for the Mahu conglomerate reservoirs，an equivalent KGD fracture propagation model was established to realize the rapid estimation of fracture shape. By using the heuristic particle swarm optimization algorithm and taking the rate of return as the objective function，a combined optimization on fracturing scale, cluster number and displacement was carried out for pay zones in the Mahu conglomerate reservoirs. The optimization results show that with the increase of the iteration number，the high-cost development plan finally converges to a combined optimization plan with the best comprehensive development effect，thus enabling the optimization of fracturing parameters for Ma 131 block. Figures and Tables | References | Related Articles | Metrics

Development Characteristics of Solution-Gas Drive in Fault-Karst Reservoirs in Shunbei-1 Block LIU Xueli, TAN Tao, CHEN Yong, XIE Hui, ZHU Suyang, WU Haoqiang, XIANG Dongliu 2023, 44 (2):  195-202.  doi: 10.7657/XJPG20230209 Abstract ( 210 )   HTML ( 17 )   PDF (2422KB) ( 122 )   Save In order to confirm whether there is solution-gas drive in the fault-karst reservoirs in the Shunbei-1 block, reservoir numerical simulation was performed to characterize the solution-gas drive in the fault-karst reservoirs. Based on the reservoir engineering method, the solution-gas-drive characteristics of the fault-karst reservoirs in the Shunbei-1 block were analyzed. The study shows that due to the large thickness of the fault-karst reservoirs in the study area, component gravity differentiation occurs simultaneously near the bottom of the well and at the top of the reservoir, leaving a large amount of solution-gas unproduced and forming a secondary gas cap. Under the action of the elastic energy of solution-gas, the decline of bottomhole flow pressure slows down, and the dynamic reserves of a single well increase to a certain extent. This process is accompanied by the decline in oil-phase driving index. With the further development of solution-gas drive, the secondary gas cap invades the bottom of the well, resulting in a rapid decline of oil production. Therefore, during the depletion development of the fault-karst reservoirs in the Shunbei-1 block, the solution-gas drive can be used to a certain extent together with development under pressure. Figures and Tables | References | Related Articles | Metrics

Feasibility of Natural Gas Miscible Flooding in Ultra-Deep Fault-Controlled Reservoirs in Shunbei-1 Block CHEN Yong, ZHU Lele, LIU Xueli 2023, 44 (2):  203-209.  doi: 10.7657/XJPG20230210 Abstract ( 202 )   HTML ( 22 )   PDF (2686KB) ( 112 )   Save The Shunbei-1 block is characterized by abundant natural gas resources，high reservoir pressure，and enriched remaining oil at the reservoir top，suggesting the potential of development by natural gas miscible flooding. Through fluid phase simulation experiment and reservoir numerical simulation，the feasibility of natural gas miscible flooding in the Shunbei-1 block was demonstrated from the aspects of crude oil phase state，miscible conditions，and injection methods. The results show that the injection of oil with CH4 has the advantages of low saturation pressure，large volume expansion coefficient，and low miscible pressure; the minimum miscible pressure when injecting CH4 is about 46.80 MPa，and the minimum miscible pressure when injecting associated gas is about 4.00 MPa lower than that when injecting dry gas. At present，more than 80% of flooding units can achieve miscible displacement by re-injecting natural gas，and water-alternating-gas (WAG) injection can delay the breakthrough of gas and water，which will improve the sweep efficiency to realize reservoir energy replenishment and equilibrium displacement. The simulation of 3-year production with different injection schemes reveals that the recovery percent is increased by 11.2%. Figures and Tables | References | Related Articles | Metrics

Numerical Simulation on Upgrading and Dilation of SAGD Ultra-Heavy Oil Reservoirs With High Heterogeneity MENG Xiangbing, SUN Xinge, LUO Chihui, MA Hong, WANG Qing 2023, 44 (2):  210-216.  doi: 10.7657/XJPG20230211 Abstract ( 188 )   HTML ( 16 )   PDF (3508KB) ( 118 )   Save The ultra-heavy oil reservoirs in Fengcheng oilfield of Xinjiang belong to continental braided river deposits，with high heterogeneity. The SAGD well group in the oilfield has problems such as long preheating period and uneven development of steam chambers. The initial reservoir dilation test can significantly improve steam injection capacity and shorten preheating period，but lacks the whole-process rock mechanics coupling analysis on reservoir dilation，which is not conducive to the optimal design of the parameters for SAGD reservoir upgrading and dilation. Based on laboratory experiments such as rock triaxial compression test，the rock mechanical parameters of highly heterogeneous reservoirs were obtained，and a numerical model of SAGD dilation and thermal production for dual horizontal wells coupled with rock mechanics was established to analyze the factors influencing reservoir upgrading and dilation. Through the hierarchical and segmented dilation simulation for the highly heterogeneous reservoirs，it is clear that the reservoir upgrading and dilation should include five stages，that is，wellbore pore-pressure pretreatment stage，stress dilation stage of steam injector and its branches，large-volume dilation stage of steam injector and its branches，steam injector and producer connection stage，and above-injector large-volume dilation stage. An upgrading and dilation strategy represented by segmental dilation of fishbone well was formed for highly heterogeneous reservoirs. Field application has shown that the proposed reservoir upgrading and dilation technology is suitable for highly heterogeneous reservoirs. The technology can shorten the preheating period by 50% and increase the oil production rate by 20%. It provides a reference for the optimal design of parameters for SAGD upgrading and dilation in highly heterogeneous reservoirs. Figures and Tables | References | Related Articles | Metrics

High Immobile Water Saturation in Linxing Gas Reservoir: Genesis and Impacts on Gas Layer Resistivity LIU Zaizhen, LI Yangbing, HU Weiqiang, LENG Jie, CAI Ruihao, XIE Lan, LIU Xueqing 2023, 44 (2):  217-223.  doi: 10.7657/XJPG20230212 Abstract ( 178 )   HTML ( 19 )   PDF (9832KB) ( 43 )   Save The gas layers in the He 4 member in the Linxing gas reservoir are low-resistivity gas layers with industrial productivity. These gas layers of diverse genesis exhibit complex gas-water relationship，making them difficult to be identified. By means of cast thin section，scanning electron microscopy (SEM)，X-ray diffraction (XRD) and nuclear magnetic resonance (NMR)，and combined with the logging response characteristics of low-resistivity gas layers，the high immobile water saturation in the low-resistivity gas layers in the He 4 member was analyzed for its genesis and impacts on gas layer resistivity from microscopic and macroscopic perspectives. The analysis results show that the microporous water within chlorite film is the main source of the high-saturation immobile water in the low-resistivity gas layers in the He 4 member. It is found that the high content of highly connected immobile water within the chlorite film can greatly reduce the resistivity of the gas layers. Figures and Tables | References | Related Articles | Metrics

APPLICATION OF TECHNOLOGY

Prediction of Present-Day In-Situ Stress in Ultra-Deep Tight Sandstone Reservoirs in Bozi Gas Reservoir，Kuqa Depression ZHANG Hui, JU Wei, XU Ke, NING Weike, YIN Guoqing, WANG Zhimin, YU Guodong 2023, 44 (2):  224-230.  doi: 10.7657/XJPG20230213 Abstract ( 203 )   HTML ( 20 )   PDF (1322KB) ( 97 )   Save The ultra-deep formations in the Kuqa depression are rich in oil and gas resources，with strong reservoir heterogeneity and obvious well-to-well productivity difference. The present-day in-situ stress plays an important role in wellbore trajectory design，horizontal well operations，and fracturing design，but the current research methods are disadvantageous in many aspects. On the basis of the measured present-day in-situ stress，the relationship between in-situ stress and logging parameters was constructed，and the prediction of the present-day in-situ stress in the ultra-deep tight sandstone reservoirs in the Bozi gas reservoir of Kuqa depression was realized by using BP neural network. The results show that BP neural network is an effective method for predicting in-situ stress，with just a small error between the predicted and measured in-situ stress values，which is generally less than 10%. In the Lower Cretaceous of the Bozi gas reservoir，the maximum horizontal principal stress is the largest，followed by the vertical principal stress，and the minimum horizontal principal stress is the smallest. Generally，the strike-slip stress mechanism is universal，and the maximum horizontal principal stress is predominantly NE-SW trending in the east and NW-SE trending in the west of the Bozi gas reservoir. Compared with sandstone intervals，the sandstone-mudstone interbedding interval exhibits a stronger fluctuation of in-situ stress and a sudden high in-situ stress locally. The horizontal wells drilled along NE-SW direction in the east of the Bozi gas reservoir and along NW-SE direction in the west are relatively stable，while the vertical wells are prone to collapse. Figures and Tables | References | Related Articles | Metrics

A Sand Body Thickness Prediction Method Based on Deep Learning From Small Sample Data and Its Application CHEN Yumao, ZHAO Hu, YANG Hongwei, WEI Guohua, LUO Pingping 2023, 44 (2):  231-237.  doi: 10.7657/XJPG20230214 Abstract ( 232 )   HTML ( 21 )   PDF (15490KB) ( 80 )   Save In the upper Es4 in Y184 well block，northern Bonan subsag of Zhanhua sag， multi-stage fan delta deposits are developed，and characterized by thin sand bodies individually，great variation laterally and sandstone interbedded with shale，making it very difficult to perform quantitative prediction，which restricts the efficient development of this well block. Through deep learning and seismic attribute prediction，virtual wells were constructed to solve the problem of insufficient training samples for deep learning in the study area. Thus，a nonlinear relationship between sand body thickness and seismic attributes was clarified，and a network model for predicting sand body thickness using seismic attributes was established. This method can accurately predict sand body thickness and lateral distribution with a significantly improved accuracy，and provides a new idea for the prediction of tight sandstone reservoirs. Figures and Tables | References | Related Articles | Metrics

Comprehensive Identification of Fractured-Vuggy Reservoirs in Tahe Oilfield WU Bo, YANG Wendong, LYU Jing, LUO Junlan 2023, 44 (2):  238-244.  doi: 10.7657/XJPG20230215 Abstract ( 221 )   HTML ( 24 )   PDF (1223KB) ( 115 )   Save In order to realize the identification of the connected fractured-vuggy structures in the Tahe oilfield，based on the seismic interpretation results of large-scale reservoirs，together with the drilling，logging，testing，tracer and other data，the reservoir types in near-well and inter-well areas were identified. By identifying the reservoirs with static and dynamic monitoring methods，the characteristic parameters of the dynamic methods for identifying reservoirs in fractured-vuggy units were determined to improve the reliability of the identification. Depending upon the types of reservoirs identified with static and dynamic methods，the connected fractured-vuggy structures were constructed according to their in spatial position relationship. The application in the identification of single-well fractured-vuggy structures in the X unit reveals that the proposed comprehensive method is more reliable in identification of fractured-vuggy structure than a single static or dynamic method. Figures and Tables | References | Related Articles | Metrics

Formation Pressure Estimation Method Based on Dynamic Effective Stress Coefficient ZHOU Yunqiu, HE Xilei, LIN Kai, QIN Siping, ZHANG Chenqiang, LIU Zongjie 2023, 44 (2):  245-251.  doi: 10.7657/XJPG20230216 Abstract ( 228 )   HTML ( 20 )   PDF (649KB) ( 147 )   Save Formation pressure which can reflect porosity，compaction，and fluid occurrence of underground rock formation is very important for discovering effective reservoirs. Regarding the status that the effective stress coefficient is set as 1 for simplification when calculating formation pressure，the dynamic effective stress coefficient considering pore structure parameters is calculated based on a unified rock skeleton model and the Gassmann equation，formation pressure and pressure coefficient are estimated by using the conventional Eaton method，and the accuracy of formation pressure estimation is improved. Taking carbonate and sandstone reservoirs as examples，the estimated formation pressures show anomalies in water layers，dry layers，and gas layers. Compared with the results obtained from the conventional Eaton method，the proposed method provides a more accurate estimate of formation pressure，thus facilitating a more reliable discovery of effective reservoirs. Figures and Tables | References | Related Articles | Metrics