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01 January 2019, Volume 36 Issue 2 Previous Issue    Next Issue

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Sedimentary Model for Lacustrine Carbonate Rocks in Lower Sha1Member of ShahejieFormation in Southwestern Margin of Qikou Sag YANG Jianping1, JIN Tongjie1, JIANG Chao2, YU Zuogang3 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150202 Abstract ( 131 )   PDF (300KB) ( 300 )   Save The petrophysical characteristics and sedimentary microfacies type of the lacustrine carbonate rocks in the lower Sha?1memberof Shahejie formation in the southwestern margin of Qikou sag are classified by means of core description, thin section observation and well logging interpretation. The lithology in this study area includes bioclastic limestone, oolitic limestone, micrite, micritic dolomite, dolomitic limestone and lime dolomite. The sedimentary microfacies of carbonate rocks are classified as particle beach, dolomitic limestone lake?bay and dolomitic bottom land. Through the analysis of different lithology logging response characteristics, the logging curve numerical characteristics of various types of carbonate rocks are summed up, and the logging identification chart for such carbonate rocks in this area. Also, the sedimentary facies models for the western slope area and the eastern step?fault zone in this area are established, respectively on the basis of analysis of the microfacies characteristics and sedimentary setting. This paper suggests that the areas surrounding the western slope swells lack of charge of terrigenous clastic materials, which allow the particle beach in high energy environment and the dolomitic limestone lake?bay and dolomitic bottom land in low energy environment to coexist, while in the areas surrounding the eastern step?fault zone swell there exist charges of terigenous clasitc materials, but only develop the lake?bay and bottom land. The sedimentary models are helpful to the carbonate reservoir prediction in the similar areas in Bohai Bay basin Related Articles | Metrics

Fluid Inclusion and Hydrocarbon Accumulation of Middle Permian Reservoir in Jiaomuchaka rea in Qiangtang Basin ZHAN Wangzhong1,2, Gesan Wangdui3, CHEN Wenbin1,2 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150203 Abstract ( 86 )   PDF (300KB) ( 202 )   Save This paper systematically analyzed the fluid inclusion samples from outcrop and QZ?5well of the Middle Permian in Jiaomuchaka area of Qiangtang basin using fluorescent indicator, microscopic temperature and salinity measures. The result shows that there are four eriods of thermal fluid events that are all relevant to the hydrocarbon accumulation. in this reservoir. The burial historical curves indicate hat the four large scale processes of hydrocarbon accumulation occurred in the Middle Middle Jurassic (170×106~165×106a) before present), the Late Middle Jurassic (165×106~145×106a), the Late Late Jurassic to the Early Early Cretaceous (145×106~122×106a) and the Middle Miocene (22×106~7×106a). The Late Late Jurassic to Early Early Cretaceous is the main period of light oil accumulation, and the Middle Miocene is the main period of natural gas accumulation Related Articles | Metrics

Characteristics of Xiazijie Slope Breaks in Mahu Sag and Control Effect on Sand Bodies QU Jianhua1, GUO Wenjian1, YOU Xincai1, WU Tao1, WANG Xuhui2 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150201 Abstract ( 70 )   PDF (300KB) ( 314 )   Save Mutli?grade slope breaks were found in Xiazijie slope area of Mahu depression, Junggar basin.3?D seismic data, combined with logging data and field reconnaissance information were used to study the characteristics of these slope breaks. Based on the genetic mechanism, the slope break can be classified as fault slope break, flexure slope break and erosion slope break. Considering with the seismic profile features, it can be further divided into 5sub-categories. The plane positions and the grades of the slope breaks with sand?body controleffect before Triassic deposition can be determined based on their lateral and vertical distribution characteristics. The fault slope break is considered to be the main type in this area, and it plays a significant controlling part in sand body distribution in lateral and vertical, which includes sand facies, sand thickness, sand layer number and sand evolution, etc. Finally, 5kinds of sand?body control models are established, such as groove control, fault control, slope barrier, slope step and slope intersection on the basis of statistics of these slope breaks and sand distribution Related Articles | Metrics

Paleokarst Characteristics and Development Patterns of Upper Ordovician Reef Flat Complex in Eastern Tazhong Area, Tarim Basin ZHENG Jian1, ZHANG Zhenghong2, ZHU Bo2, SU Dongpo2, WANG Zhenyu1, QU Haizhou1 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150204 Abstract ( 49 )   PDF (300KB) ( 56 )   Save Based on study of sedimentary setting and structural feature of Lianglitage formation, integrated with analyses of drilling, core, well logging and geochemical data, the sedimentation of Lianglitage No.3to No.2members of the Upper Ordovician is dominated by continually vertical accumulation during highstand system track, which is the main development period of reef?flat complex. The vertical zonality of denudation and cementation in the reef?flat complex is obvious under control of the multi?phase reef?flat complex constructions and eustatic secondary cycles, and the secondary pore spaces mainly develop in the atmospheric vadose zone and upper phreatic zone, while cementation occurs in the bottom of phreatic zone. Atmospheric diagenetic lens formed by selective denudation are mainly distributed in the middle?upper parts of the individual phase of reef?flat sedimentary cycles, which becomes the effective storage and seepage spaces composed of intragranular solution pore, moldic pore, intergranular solution pore, and intermittently distributed along the high energy facies belts of the rimmed platform. The syngenetic paleokarst feature, the reservoir control mechanism and dev Related Articles | Metrics

Identification of PaleoOilWater Contact of Jurassic Ahe Formation in Dibei Area, Kuqa Depression, Tarim Basin LIU Jianliang1,2, JIANG Zhenxue3, LI Feng3, WANG Ying4 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150205 Abstract ( 47 )   PDF (300KB) ( 204 )   Save Abstract:The area with multiphase hydrocarbon charges and multistage tectonic movements allows the oil and gas accumulation process research to be more difficult. This paper presents the oil?water contact identification of the Jurassic Ahe reservoir in Dibei area of Kuqa depression using oil inclusion abundance approach and quantitative grain fluorescence technique. The results show that there exists the palaeo-oil reservoir of Ahe formation in Yinan?4and Yishen?4wells with oil column height of over100m, and in Yinan?4well, no Ahe oil reservoir is found, but it plays a part in hydrocarbon migration pathway. Combining the tectonic evolution and the hydrocarbon generation history in Kuqa depression, this paper suggests that during the Middle to Late Miocene, the Triassic source rocks are in peak period for oil generation, making the generated oil migrate up to the Jurassic Ahe formation and form the paleo?reservoir in Yinan?4and Yishen?4wells that located at structural high. The delineation of palaeo?oil?water contacts in this area can provide a reliable and advantageous evidence for study of the hydrocarbon accumulation process and determination of the exploration target in the future. Key Words:Kuqa depression; Dibei area; Jurassic; Ahe formation; palaeo?oil?water contact; paleo?oil reservoir model Related Articles | Metrics

SeaLevel Variation of Late Ordovician in Eastern Margin of Maigaiti Slope by Strontium Isotope Ratio Analysis HAO Yanzhen1,2, PAN Ming1,2, LIANG Bin1,2, ZHANG Qingyu1,2, DAN Yong1,2, SUN Chengjie3 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150206 Abstract ( 50 )   PDF (300KB) ( 108 )   Save The strontium isotope characteristics of23carbonate samples of Lianglitage formation of Late Ordovician from Ma?2well in Maigaiti area of Tarim basin were analysed for the purpose of making sure the sea?level changes at this period. The results show that the ratio of 87Sr/86Sr ranges from0.70851to0.70901, with an average of 0.70874, which is higher than the ratio of global seawater strontium isotope in the same period, but more consistent with those from the same horizons in such areas as Keping, Bachu and Tazhong regions. On the basis of the ratio of 87Sr/86Sr, the strontium isotope evolution curve of Lianglitage formation in Maigaiti area is obtained, which is consistent with the global seawater strontium isotope evolution curve of the Late Ordovician, better coupled with Bachu, Laurentia and Baltica old?lands, and well reflects the sea?level variation in this period. This understanding is of great importance for the study of the sediment changes and structural evolution of Late Ordovician in the whole Tarim basin Related Articles | Metrics

Characteristics of Xujiahe Member4Reservoir of Upper Triassic in Puguang Gas Field,Sichuan Basin KUANG Hao1, YU Qikui2, XUE Kunlin3a, YU Juan3b, HUANG Ligong3b 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150207 Abstract ( 48 )   PDF (300KB) ( 77 )   Save With in?depth exploration of natural gas in marine strata in Puguang gas field of Sichuan basin, more and more gas shows are found in its continental strata, of which the member?4reservoir of Xujiahe formation of the Upper Triassic has become the succeeding layer of the major productivity in future in this area. Based on the core, thin?section and well logging data analysis, the characteristics of this reservoir were discussed. Lithology of the reservoir is dominated by lithic sandstone of braided river delta sediment, followed by feldspathiclithic sandstone, and reservoir space is given priority to with secondary intergranular pores, followed by remained primary pores. Compaction and cementation are main factors to destroy the reservoir quality rather than dissolution. The underwater distributary channel and mouth bar are sedimentary microfacies with good reservoir property, next to distributary channel microfacies, which are key targets for next exploration and development in the area Related Articles | Metrics

Sedimentary Evolution of theMember1of Permian Wutonggou Formation in Jimusaer Sag, Junggar Basin CHEN Chunyong1, TAN Qiang1, ZHANG Jinfeng1, WANG Jing1, YUAN Chunlin2a, KANG Yongshang2a,2b 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150208 Abstract ( 56 )   PDF (300KB) ( 170 )   Save The Wutonggou formation of Upper Permian is one of the important hydrocarbon sequences in Jimusaer sag of Junggar basin, and the Wu?1member is the main oil producing zone. In this paper, five sand layers and sedimentary evolution laws of the Wu?1 memberwere studied for the purpose of the requirements of deepening petroleum exploration. The results show that there are several inherited braided river deltas developed in different stages of Wu?1member episode, and Ji?15well west and Jinan inherited braided river deltas as well as Beisantai swell southwest slope and Santai paleo?uplift small?scale fan deltas are identified for the first time. Along with lake extension, the inherited braided river deltas of Wu?1member moved away from the sedimentary center, which were favorable for formation of lithologic traps surrounding Jimusaer sag. The inherited braided river deltas developed in different stages have the retrograding contact relations among them, and the sand bodies of the lower sand layers are distributed in the central of the sag, while the sand bodies of the upper sand layers are distributed around the sag margin Related Articles | Metrics

Tight Oil Reservoir in Qianjiang Sag of Jianghan Basin: Characterstics and Origin SONG Huanxin1, CHEN Bo1, SHEN Junjun1, CHEN Lixin2 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150209 Abstract ( 75 )   PDF (300KB) ( 171 )   Save The dolomite tight reservoir ofⅡoil layer of Xingouzui formation (Exl?Ⅱ) in Xingou area of Qianjiang sag is in low degree of exploration and research. This paper studied the crude oil geochemistry, oil source and genetic type in this reservoir, based on analysis data of the oil and hydrocarbon source rocks samples. The results show that the dolomite reservoir of Exl?Ⅱis of typical feature of tight oil reservoir, which is medium?low porosity, ultra?low permeability and super?small throat, and stronger potential of generating low?mature oil with high organic abundance and low thermal evolution of the muddy source rocks. The characteristics of the biomarkers indicate that the low?mature oil belongs to typical one from the saline lacustrine mudstone in source rocks of structural low, with both source and reservoir and short secondary migration. The parent materials of the oils are dominated by mixed types of organic matters including terrestrial higher plants, plankton and algae, etc. The early hydrocarbon generation of biological lipid is the main hydrocarbon?generating model for low mature oils in this area, while early degradation of sulfur?rich macromolecular could be its one of important models for hydrocarbon generation Related Articles | Metrics

Evaluation of Ordovician Source Rocks in Western Margin of Ordos Basin WU Chunying, JIA Yani, HAN Huiping, KANG Rui, HUANG Zhengliang, SUN Liuyi 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150210 Abstract ( 59 )   PDF (300KB) ( 269 )   Save It has been a bottleneck in oil and gas resources evaluation and exploration progress for low studied degree of the Ordovician source rocks and hydrocarbon?generated potential in western margin of Ordos basin. This paper systemically analysed the general characteristics and hydrocarbon?generated potential of them by means of organic petrology and geochemistry methods. The study shows that the Ordovician source rocks are mainly developed in Kelimoli formation and Wulalike formation in this basin, which is a set of deep marine shale and muddy carbonate rocks of wide distribution and large thickness. The Ordovician source rock is characterized by high abundance of organic matter, kerogen type?Ⅰfollowed by type?Ⅱ1 and high to over maturity stage, with good hydrocarbon potential, and the hydrocarbon generating centers of the north?south belt crossing Tianhuan central district Huitan?1well?Na?1well?Di’e?3well could be the favorable exploration targets in the future Related Articles | Metrics

PoreMicrocrack Characteristics of Longmaxi Black Shales in Fenggang Area, Guizhou Province YAN Gaoyuan, ZHU Yanming, WANG Yang, ZHOU Ze, SONG Yu, TANG Xin 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150211 Abstract ( 58 )   PDF (300KB) ( 168 )   Save The wild field investigation and the systematic sample collection were conducted, and the collected samples were experimentally tested using SEM, mercury injection, nitrogen and carbon dioxide adsorption. The results show that the target zone is dominated by intercrystal pore, intergranular pore, corrosion pore and microcrack, with pore size of1~10μm, a few reaching10~20μm measured by SEM;5~800nm for major pore size by mercury injection, and that of larger than5nm accounts for over90%, the specific surface area and pore volume of2.12m2/g and 0.0128mL/g, respectively, and porosity of2.78%; for low-temperature liquefied nitrogen and carbon dioxide adsorption tests, their specific surface areas average12.8m2/g and8.78m2/g, pore volumes are0.0112mL/g and0.0025mL/g, pore sizes are4.67nm and0.495nm, respectively. It is concluded that the pore system of the target is more developed and connected, with higher porosity, larger specific surface area and pore volume, favorable for adsorption, migration and accumulation of shale gas as a good quality of reservoir Related Articles | Metrics

InjectionProduction Parameters Optimization at Startup Phase of SAGD in Fengcheng Oilfield, Junggar Basin HUO Jina, SANG Linxianga, LIU Minga, L?Bolina, JIANG Dana, YANG Haozhea, HUANG Ligongb 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150212 Abstract ( 63 )   PDF (300KB) ( 151 )   Save The large?scale application of steam assisted gravity drainage (SAGD) technology began in2012in Fengcheng oilfield. In order to ensure the circulation preheat performance, increase the horizontal section’s connecting degree and improve reservoir development efficiency, it is necessary to conduct the research of injection?production parameters optimization at the startup phase. In this paper, the objective function and the injection?production parameters of startup phase were confirmed by reservoir numerical simulation. Sensitivity analysis was done by compared simulation of“two goals and three factors”. The injection?production parameters optimization was then made according to their influencing results. Simulation results show that the high pressure and increasing temperature and the low steam consumption at startup phase should be adopted as follows: the preheat pressure is controlled by0.5~1.0MPa less than reservoir fracture pressure; the pressurization time is1~3days following uniform temperature in horizontal section; the steam injection rate reduces as much as possible in condition of horizontal section temperature equilibrium. The case study indicates that the optimization technology is practical and effective Related Articles | Metrics

Application of TypeD Water Drive Curve to Development Index Forecast in Donghe Sandstone Reservoir in Hadeson Oilfield, Tarim Basin NIE Yanbo1, WU Xiaohui2, QIAO Xia1, WANG Yueyan2, ZHANG Shaowei1 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150213 Abstract ( 64 )   PDF (300KB) ( 166 )   Save Donghe sandstone reservoir in Hadeson oilfield is a massive sandstone reservoir with interlayers and edge?bottom water. Horizontal well is the main recovery process integrated with vertical well. Depletion process is adopted in pure oil zone and transitional zone during the preliminary stage, followed by combined process of depletion with artificial water injection. In view of preliminary?stage high production, low water cut, and mid?to late?stage high water cut and rapid production decline in this reservoir, this paper conducted the comparative analysis of the water drive characteristic and the production performance, showing that Type?D water drive characteristic is more suitable for the reservoir, and using Type?D curve to calculate the development indexes such as production rate, water cut, recoverable reserves, etc. can give high forecast precision of them, which have provided a reliable basis for exploitation effect evaluation, adjustment scheme compilation and development planning Related Articles | Metrics

Evaluation of Stimulated Reservoir Volume (SRV) in Tight Oil Reservoirs by Horizontal Well Multistage Fracturing Process LIU Weidong1, ZHANG Guodong2, BAI Zhifeng2, LIU Jinjun1, TANG Xiaochuan1 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150214 Abstract ( 69 )   PDF (300KB) ( 144 )   Save Based on the Middle Permian Lucaogou tight oil reservoir characteristics in Changji oilfield, this paper developed the simulation model of horizontal well multistage fracturing process, and by which studied the effects of nature fractures, fracture parameters and fracture shapes on the stimulated reservoir volume (SRV) and cumulative oil production. The results show that during early stage of exploitation, fracture parameters are the main factors affecting the production of oil wells; after entering into middle?late stage, SRV has more and more control effect on the production; while the secondary fractures and the number of fractures are the main factors affecting SRV and cumulative oil production. And the effects of secondary fractures, fracture permeability, and half?length of fracture on the well cumulative production are focused on the early period of development; the effects of the spacing and geometry of fractures are focused on the middle?late stage of development. The influence of the number of fractures runs through the entire development period. The SRV values corresponding to shuttle, trumpet and uniform types of fractures are approximately the same, while the SRV value for dumbbell type of fracture is smaller Related Articles | Metrics

Laboratory Optimization of PolymerGel Flooding Control System for High Temperature Reservoir in Hejian Dongying Oilfield ZU Lihua, REN Hongmei, CAO Bin, ZHANG Yuzhen, WANG LI, LIU Wei 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150215 Abstract ( 70 )   PDF (300KB) ( 191 )   Save The criteria for screening the polymer?gel system was laid out according to the high temperature reservoir conditions of Hejian Dongying oilfield. A suitable HPAM/Phenol Formaldehyde gel system was screened from the five candidates based on the criteria. Orthogonal experiments were carried out using the30?day viscosity value and the average retention rate of the gelled system as evaluation indexes. The order of the factors influencing gelling strength and long?term stability is as follows: polymer>cross linker>assistant agent. Finally, the best formula (1200mg/L of polymer+2250mg/L of cross linker+1750mg/L of assistant agent) was determined based on the formulation optimization experiment. As of the midmonth of December in2014, the pilot tests have been carried out in ten well groups, of which six wells preliminarily became effective and seven wells obviously effective. The average wellhead pressure was increased by5.32MPa and the cumulative incremental oil production was1262tons Related Articles | Metrics

Application of High Density and Wide Azimuth Seismic Data Processing Technology in Mahu Sag, Junggar Basin LOU Bing, YAO Maomin, LUO Yong, ZHENG Hongming, ZHANG Long 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150216 Abstract ( 49 )   PDF (300KB) ( 49 )   Save The main challenge of oil and gas exploration in Mahu sag can be summarized as "low, deep, thin and subtle", namely, low structure amplitude, deep target zone, thin layer and subtle reservoir. It is suggested that high resolution and amplitude fidelity of the seismic data are the key factors to solve these issues. This paper focused on model methods for slip sweep harmonic noise suppression, common offset frequency interference suppression, the surface and deep step inverseQfiltering technique, OVT (offset vector tile) domain processing, and applied them to Muhu sag. The real seismic data processing results show that the new technology can be used to effectively suppress the strong harmonic interference and random noise, improve the resolution of seismic data, widen the effective band of the high frequency of seismic signal end by about15Hz, which is helpful to characterize the Triassic unconformable pinchouts and identify the thin sand bodies; in the OVT domain, the processed prestack seismic gathers data are of high fidelity in amplitude changing with offset and azimuth information, and lay a solid foundation for high quality glutenite reservoir identification and prediction Related Articles | Metrics

Realization Method and Effect of the Spatial Domain CMP Reference Datum ZHENG Hongming1, KANG Yueping1, JIANG Yuangang1, TAN Lei2, QIN Rui2, ZHENG Chao2 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150217 Abstract ( 70 )   PDF (300KB) ( 210 )   Save Seismic data processing and interpretation will involve the datum level problem, and the influence of different datum levels on the results is different. The datum defined by conventional static correction method can meet the requirements of seismic data processing, but there are some deficiencies, such as time?depth conversion of the datum, error between smooth surface and CMP datum, etc. In this paper, back?calculation of the datum is based on the known surface structure parameter, by which not only make the static correction in line with the principle of minimum, but also allow each CMP gather to have individual horizontal datum, give the datum more accurate above?sea?level meaning, and be able to get a elevation datum from profile interpretation and structure?depth conversion for comprehensive research, while having satisfied the requirements of seismic data processing, thus avoiding the errors of CMP datum conversion in time domain. The theoretical model tests show that the structure accuracy of the depth?domain profile in this approach is obviously improved compared to the conventional datum method. It provides a powerful means for petroleum exploration in low?amplitude structures Related Articles | Metrics

Quantitative Evaluation of Fault Sealing with Improving SGR Method: A Case Study of Yingmai?34Well Area in Tabei Uplift, Tarim Basin GUAN Wensheng1,2, ZHA Ming1, ZHANG Chao2, ZENG Liping2, SUN Qi2, BAI Yin2 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150218 Abstract ( 75 )   PDF (300KB) ( 232 )   Save The method for estimating highest hydrocarbon column supported by the fault with shale gouge ratio (SGR) has not been used in Yingmaili area, Tarim basin. By improving the formula of SGR, combining with the reservoir and seismic data, this paper estimates for the first time the parameterd, the reservoir oil?column height in Yingmai?34well area, then the hydrocarbon column heighthin trap of this well area, making sure the effective trapping ranges, which is helpful for quantitative evaluation before drilling and reducing the exploration risk. Related Articles | Metrics

Comparisons of Fault Capacity Dimension and Information Dimension with Numerical Simulation in Fracture Prediction LIU Jingshou, DAI Junsheng, WANG Shuo, ZHANG Xiangcheng 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150219 Abstract ( 46 )   PDF (300KB) ( 183 )   Save According to the fact that Minqiao oilfield is of simple structure and more faults, the fracture distribution in its reservoir is predicted by means of fault capacity dimension and information dimension method, the prediction result is compared with the result of numerical simulation of structural stress field. The result shows that Minqiao oilfield has three fracture developing areas, and the fracture’s distribution trends predicted by fracture information dimension method and numerical simulation method are basically consistent. The fault activity is linearly proportion to fault width, the fault’s area information entropy reflects the fault activity in a certain extent, and overcomes the shortage of simple capacity dimension in characterization of fracture distribution. The fault width and spacing are essential factors that influence the fracture development. The fractal characteristics of the fault is of scale and the accuracy predicted by using fractal method is much lower than that by numerical simulation of structure stress field, specially in prediction of the local distribution of fractures. The numerical simulation is not accurate in predicting multistage fracture superimposition area. Related Articles | Metrics

Granite Reservoir Evaluation While DrillingMethod and Application WANG Junrui, DENG Qiang, TAN Weixiong, GONG Ming, QIN Lei 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150220 Abstract ( 38 )   PDF (300KB) ( 64 )   Save The studies of complex lithology reservoir mostly was confined to carbonate rocks at home and abroad, and the researches aimed to granite reservoir evaluation, especially the method for estimation while drilling also lacked of systematization and quantification. This paper, for the first time, introduced work index model to assess granite reservoir. According to the in?depth analysis of the model, the concrete steps for debugging of key coefficients of the model, drawing of work index trend line and calculation of work index ratio were elaborated, thus establishing a qualitative reservoir identification method while drilling based on work index ratio. Meanwhile, by calibrating work index ratio from the results of imaging logging, the evaluation criterion of reservoir property was established, achieving the semi?quantitative assessment while drilling for reservoir property for the purpose of providing certain references for preventing engineering risks such as leakage and borehole collapse. The application results show that this method is more accurate than single drilling time recognition method for granite reservoir identification, and consistent with the comprehensive log interpretation results as required in field exploration. Related Articles | Metrics

Enlightenment from the Debate about Directions for Oil and Gas Exploration in Junggar Basin in1950s LIN Longdong 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150221 Abstract ( 69 )   PDF (300KB) ( 199 )   Save In the early1950s there was a big debate about directions for oil and gas geological exploration in Junggar basin: whether to go platform (refers to the northwestern margin of the basin) or to be persisted in the piedmont depression (refers to the southern margin of the basin) for continuing to oil exploration. Over the past60years, with the deepening of the oil and gas exploration and constant accumulation of the new information or data, a new idea or model for oil and gas exploration in Junggar basin is appeared in recent years. According to this new model, this paper presents reappraisal of oil and gas prospects in the northwestern margin and the southern margin of Junggar basin, and indicates that the oil and gas prospect in the northwestern margin is much better than that in the southern margin of the basin. The success of the oil and gas exploration in the northwestern margin in recent years is a successful case based on the new model for further finding oil and gas in Junggar basin. Related Articles | Metrics

Discussion on the DualEffective Stresses of Porous MediaReply to Dr Hong Liang LI Chuanliang 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150222 Abstract ( 95 )   PDF (300KB) ( 251 )   Save The dual effective stresses of porous media were established in1999and have been widely applied nowadays. The concept of dual effective stresses was proposed after Terzaghi effective stress and Biot effective stress. Terzaghi effective stress is only applicable to extremely loose porous media approximately, and Biot effective stress is an empirical formula, which have some defects. The dual effective stresses overcome the defects of them by taking consideration of deformation mechanism and material structure of porous media. Porous media have two typical deformations: primary deformation and structural deformation. Correspondingly porous media have two effective stresses: primary effective stress and structural effective stress. Primary effective stress determines the primary deformation of porous media, while structural effective stress determines the structural deformation. By introducing parameters of material structure of porous media into the formula, the dual effective stresses unified porous media and common solids using porosity, so can get wider applications than Terzaghi effective stress and Biot effective stress. Related Articles | Metrics

Dolomitization in Carboniferous Carbonate Reservoir in Southern Zahnanor Oilfield in Eastern Margin of PreCaspian Basin ZHANG Shengbin1, SHENG Han2, JIN Bo3, SONG Yahui4 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150223 Abstract ( 96 )   PDF (300KB) ( 190 )   Save The Pre?Caspian basin is one of the giant oil?gas bearing basins in the world, and the Carboniferous carbonate rocks in its eastern margin are favorable hydrocarbon reservoirs. By means of logging interpretation, core analysis and contrastive analysis, existence of the Дlayer dolomite in KT?Ⅱpetroleum system in southern Zahnanor oilfield was verified for the first time. The study of the dolomitization feature and reservoir control factors show that the dolomite is mainly distributed in the bottom of Д1 layer, and the rock porosity tends to increase with the increase of dolomite content, but the trend is not obvious when dolomite content is less than20%. The dolomitization does not always increase the porosity, only a certain degree of dolomitization can significantly influence on petrophysical property, too low or too high degree of it is unfavorable to improve the reservoir quality. When the dolomite content is over80%, the rock porosity may decrease to about6.5%. The control factors on the carbonate reservoirs in this area are multiple, of which dolomitization is of great importance and crucial for the development of high quality reservoirs in this area. Related Articles | Metrics

Production Decline Rule and Recoverable Reserves Prediction of Marcellus Shale Gas Well in A Production Unit, Pennsylvania, HE Pei1, FENG Lianyong1, Tom Wilber2 2015, 36 (2):  1-1.  doi: 10.7657/XJPG20150224 Abstract ( 59 )   PDF (300KB) ( 151 )   Save U.S. is the first country of large-scale and commercial development of shale gas in the world for its abundant shale gas resources. Since the production decline regularity of shale gas well is obvious, it is of great academic value and practical value to study it. Based on the actual production data from a shale gas production unit in Pennsylvania, the method of decline curve analysis was adopted, the type of decline curve was determined, and the single well production and recoverable reserves were predicted. The results show that the shale gas wells of this unit are in line with the hyperbolic decline type, and the single well technical recoverable reserves could be higher. Related Articles | Metrics