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01 January 2019, Volume 34 Issue 2 Previous Issue    Next Issue

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Analysis of Shale Gas Potential of Niutitang Formation of Lower Cambrian in Guizhou, China YUE Laiqun1, KANG Yongshang2, CHEN Qingli3, SHANG Yuenan2, SHE Zhenbing4, CHEN Ling5 2013, 34 (2):  1-1.  Abstract ( 230 )   PDF (300KB) ( 238 )   Save The black shale of Niutitang formation of Lower Cambrian in Guizhou province is widespread, thick, high in organic content and formed in anaerobic, euxinic and stagnant marine environment, with reserves of about 1 960×108 m3 . The multi?episode tectonic movements and thermal events resulted in its complex occurrence and partial micro?metamorphism, but the black shale still has certain of shale gas potentials in it, deserving to make further studies. It is suggested that in the future geological exploration and development of shale gas should consider the black shale, tight clastic rocks and carbonate rocks and their reservoirs in Guizhou Related Articles | Metrics

The Practices for Exploration Breakthrough in Sinopec Prospecting Area in Northwestern Margin of Junggar Basin SUI Fenggui 2013, 34 (2):  1-1.  Abstract ( 72 )   PDF (300KB) ( 262 )   Save The Sinopec prospecting area located in the slope belt of northwestern margin of Junggar basin is composed of the west?margin block and the north?margin 1 block, with simple structures, undeveloped fault scale, overlying?stripped and superimposed strata and far from the source rocks, so being of a great difficulty in petroleum exploration. On the basis of comprehensive researches, it is suggested that the studied areas are generally characterized by distal source supply of hydrocarbons. The Permian source rocks in the north?margin block are extended toward the north at the overthrust structural belt in Hala’alate mountain, while the west?margin block in Chepaizi is characterized by dual?source and dual?direction oil supply. Through analysis and evolution of the oil?gas transport or migration conditions, the distal?source hydrocarbon accumulation model by fault?blanket style of oil migration was established, and the main type of traps was verified. The updip pinch?out lithologic reservoir in reef?bar sand body in southern zone of Chepaizi swell and the stratigraphic?lithologic reservoirs in east of the swell and in south of the Hala’alate mountain were selected as targets for petroleum exploration, and the relevant matching technologies were proposed. Finally, the two oil?bearing areas of 1×108 t reserves have been discovered in Chepaizi area and Hala’alate mountain area for important exploration breakthrough Related Articles | Metrics

Hydrocarbon Accumulation Assemblage and Evolution in Huomatu Structural Belt in Southern Margin of Jungar Basin LEI Dewen1, ZHANG Jian2, BAI Zhenhua3, FANG Shihu4, ZHAN Yantao4, WEI Lingyun2 2013, 34 (2):  1-1.  Abstract ( 61 )   PDF (300KB) ( 213 )   Save In this paper, the techniques such as oil?gas maturity parameters characterization, inclusion microstructure observation, reservoir bitumen testing and grain fluorescence are used to analyze oil and gas charging sequence and history in Huomatu structural belt. The study suggests that the oil in Huomatu structural belt comes from the source rocks of Tugulu group of Lower Cretaceous, whereas the gas from the coal?measure source rocks of Jurassic. There are two main stages of hydrocarbon accumulation in Huomatu structural belt: the first stage is about 10 Ma ago, dominated by charging of low maturity oil; the second stage is about 3 Ma ago, dominated by gas charging and accompanied with higher maturity oil. Such an early oil and late gas charging and evolution pattern suffers late adjustment and reconstruction, with gas?invaded fractionation locally Related Articles | Metrics

Petroleum Accumulation Mechanism and Controlling Factors in Baijiahai Swell, Junggar Basin HU Haiyan1, WU Jian2, HUANG Yun2, TAN Sizhe1, CHEN Yuanyong1, LIU Zuoqiang1 2013, 34 (2):  1-1.  Abstract ( 72 )   PDF (300KB) ( 265 )   Save The control factors of petroleum accumulation in Baijiahai swell of Junggar basin are discussed in terms of oil/gas source, transport system and paleo?structural evolution, etc. The results show that the oil/gas source originated from the Permian hydrocarbon source rock, the Jurassic coal?measure source rock and both of them; the fault/fractures, structural ridge?sand body are as the favorable transport system; the multi?migration and changes occurred in its geological history period for the paleo?structural highs in this swell, and the reservoirs discovered nowadays are mainly distributed along these highs. When hydrocarbons in the source rocks were generated and expelled, the opened fractures and sand bodies became the preferred oil/gas migration pathways until the oil/gas entered into the paleo?highs. And the paleo?traps were seldom influenced by late tectonic movements. Therefore, the present reservoirs in this area are all characterized by their distributions along the paleo?highs Related Articles | Metrics

OilGas Exploration Status and Future Targets in Bohai Bay Basin LI Xin, LI Jianzhong, YANG Tao, YAN Weipeng, GUO Bincheng, L? Weining, CHEN Xiaoming 2013, 34 (2):  1-1.  Abstract ( 116 )   PDF (300KB) ( 390 )   Save The exploration degree of Bohai Bay basin is relatively high, compared with the American oil?gas exploration degrees in similar basins, the Bohai Bay basin is in the late stage of reserves stable growth and still has the resource potential for deepening exploration. The study shows that the conventional reservoirs of clastic rocks, the deep buried hills and inner buried hills are still major exploration domains to achieve the steady growth of reserves and production. Meanwhile, the petroleum resources in tight sandstone and lacustrine carbonate reservoirs amount to (15~18)×108 t and 12×108 t, respectively. Tight sandstone gas resource amounts to about 6.3×1012 m3. These unconventional oil and gas reservoirs will be important succeeding domains for petroleum exploration in the future. Therefore, at the present stage, the unconventional oil and gas reservoirs should be explored and paid more attention to so that achieves the sustainable development of oil and gas exploration in this basin Related Articles | Metrics

The OilGas Migration Patterns in Shanan-Beisantai Area in Eastern Junggar Basin LIU Junbang1, LIU Zhen2, JING Xiaofeng2, LI Peijun3 2013, 34 (2):  1-1.  Abstract ( 69 )   PDF (300KB) ( 416 )   Save With the deepening of exploration practices and researches of Junggar basin in recent years, the previous understandings of the oil?gas migration patterns in Sha’nan-Beisantai area in eastern Junggar basin (Jundong area) cannot satisfy the present exploration demands. In view of such a challenge, this article studies the source rock distribution and transporting pathways, presents in?depth analysis of 19 oil reservoirs in two oil fields in this studied area, and then proposes new T?type transporting model for dominant oil?gas migration as vertical direction and short distance in Jundong area, including the significance of the T?type model on the petroleum exploration, which provides new idea for the oil?gas exploration in Jundong area Related Articles | Metrics

Formation Mechanism and Petroleum Geological Significance of Physical Weathering Layer in Western Qaidam Basin YUAN Hao1,2, WANG Haifeng3, XIANG Haiyang3, LIAO Qiming3, CUI Ligong3, CHEN Lei3 2013, 34 (2):  1-1.  Abstract ( 83 )   PDF (300KB) ( 191 )   Save The formation mechanism and the forming time of the physical weathering layer in western Qaidam basin are determined by study of paleo?climatic evolution and regional tectonic evolution since Paleogene. The physical weathering layer is formed by dual role of the dry and cold extreme plateau climate and the intense tectonic compression and deformation during the late Himalayan movement. The physical weathering layer, water layer and oil layer in this area constitute obvious“triple?section style”in vertical. The water level under the physical weathering layer appears diachronous phenomenon, thus it cannot serve as a marker bed for stratigraphic isochronal correlation. In drilling engineering, the physical weathering layer could be easily resulted in circulation loss and borehole collapse for it to reduce seismic signal?to?noise ratio and impact seismic data acquisition Related Articles | Metrics

Structural Characteristics in Esma Area in Qiangnan Depression of Qiangtang Basin, QinghaiTibet Plateau WU Tao, MA Desheng, FU Hongbin, LONG Shengqing, BAI Peirong, ZENG Yuren 2013, 34 (2):  1-1.  Abstract ( 59 )   PDF (300KB) ( 184 )   Save It is suggested from surface oil?gas geological survey and by using modern structural interpretation theory and methods that the Esma anticline given by previous seismic interpretations is a hidden anticline, and Esma area is of better conditions for the oil?gas structural trap and the complete conservation of petroleum system of the Mesozoic. Study of the structural evolution is helpful to recognize the formation and distribution of the reservoirs in this area Related Articles | Metrics

Diagenesis of Tongbomiao Volcanoclastic Rocks in Tanan Sag in Hailaer-Tamuchag Basin, Inner Mongolia MA Limin1, LIN Chengyan1, WEN Gangfeng2,3, NI Xiaohua1 2013, 34 (2):  1-1.  Abstract ( 60 )   PDF (300KB) ( 744 )   Save The cores, thin?section and SEM data were used to research the diagenesis of volcaniclastic rocks and its effects on reservoir quality of Tongbomiao formation in Tanan sag in Inner Mongolia. The results show that the volcaniclastic rocks of Tongbomiao formation mainly consist of ignimbrite, tuff, tuffites, tuffaceous sandstone and tuffaceous conglomerate. In addition to the compaction, cementation and dissolution, the diagenetic characteristics of the volcanoclastic rocks are of peculiar properties, compared with normally sedimentary clastic rocks, such as clinkering process, devitrification and recrystallization. The clinkering and devitrification processes result in abundant secondary pores which improve the physical property of the reservoir. The existence of microcrystalline quartz cladding is beneficial to the conservation of primary intergranular porosity. The compaction and the carbonate cementation are mainly factors to allow the reservoir quality to be poor Related Articles | Metrics

Genesis of HighQuality Reservoir in UltraDeep and ReefBank Carbonate Rocks of Ordovician in Tazhong Area, Tarim Basin QU Haizhou1a,1b, WANG Zhenyu1a,1b, ZHANG Yunfeng1a,1b, YANG Haijun2, SUN Chonghao2, WANG Xi2 2013, 34 (2):  1-1.  Abstract ( 61 )   PDF (300KB) ( 290 )   Save Based on the core and thin section data, the measured physical properties and the well logging information, it is indicated that the Lianglitage reservoir is characterized by the matrix porosity and the macro?vugs and fractures superimposed development within 100 m below the top. The polycyclic thick reef?bank complex deposited in the suitable sedimentary environment of the Late Ordovician is favorable material basis for the reservoir?forming. The non?selective solution pores formed in the early diagenesis and near?surface karst play roles of superimposition and modification on such a reef?bank complex, which are the key factor for forming the ultra?deep and high?quality carbonate reservoirs in this area. The fractures formed by tectonic disruption in burial stage communicate the pores, and provide pathways for migration of multiple fluids. These fluids create dissolution or inhibiting cementation to the surrounding rocks, which could guarantee the reservoir and percolation capacity for the deeply buried carbonate rocks. Controlled by these factors, the pores evolution has undergo eight stages, of which three?stage oil?gas migration in the burial stage has good time?space configuration with the three stages of porosity development, hence forming the large condensate gas reservoir of ultra?deep and reef?bank complex of the Ordovician in Tazhong area Related Articles | Metrics

Enrichment and Exploration Prospects in Deep Volcanic Gas Reservoirs in Songliao Basin LIN Shiguo1,2, ZHAO Zehui2, XU Shujuan2, JIANG Xiaohua2, DING Peng1, CHENG Honggang2, CHEN Jun’an2 2013, 34 (2):  1-1.  Abstract ( 68 )   PDF (300KB) ( 259 )   Save The deep zone of Songliao basin is made up of a group of separated fault depressions. The volcanic rocks are the major reservoirs for deep gas exploration. Based on systematically analyses of the formation condition and the gas accumulation pattern, it is suggested that the deep volcanic gas reservoirs are characterized by the short distant migration, distribution around main trough and along the fault, and controlled by source rocks, reservoirs and faults. The areas with both developed source rocks and volcanic reservoirs are the favorable exploration zones. For exploration prospect, there are many fault depressions that have not yet made a breakthrough, such as Yingcheng formation and Huoshiling formation which are all exploration targets with potentials. The widespread deep clastic rocks where the source rocks directly connected with reservoirs in large area could be as important succeeding zones for deep exploration in this basin Related Articles | Metrics

Mechanism of Controlling of Fault on Oil Accumulation in Laizhouwan Sag in Southern Bohai Bay Basin ZHANG Shuang, YE Jiaren, LIU Wenchao 2013, 34 (2):  1-1.  Abstract ( 66 )   PDF (300KB) ( 257 )   Save Laizhouwan sag is the hydrocarbon?rich sag controlled by the multi?episode movements of Tanlu fault. The fault evolution has important effects on the hydrocarbon generation, migration and accumulation in the sag. The rapid subsidence in the faulted period caused development of high?quality source rocks of E2s41 and E2s23. At the same time, the fault communicating with deep thermal source allows it to flow up, leading to high geothermal gradient which accelerated the maturity evolution of the source rocks. So the fault becmes advantageous channels for vertical hydrocarbon migration, and controls the vertical expulsion of hydrocarbons. The late intense fault activities have certain destructive effects on the early preexisting oil and gas reservoirs Related Articles | Metrics

Comparison of Shallow Hydrocarbon Accumulation Conditions Between Dongpu Sag and Dongying Sag in Bohai Bay Basin FENG Zhendong1, CHENG Xiushen1, LIU Hailei2a, WANG Xiatian2b, ZHANG Xiaogong2b, L? Lanfang1 2013, 34 (2):  1-1.  Abstract ( 48 )   PDF (300KB) ( 185 )   Save By comparisons of the petroleum gevlogic conditions between Dongpu sag and Dongying sag in Bohai Bay basin, the reasons for the differences in hydrocarbon resources and 3D spatial distribution of these two sags are presented. The study shows that Dongpu sag is not as superior as Dongying sag in shallow reservoir?forming condition. It has the possibility of small?scale hydrocarbon accumulation or reservoir?forming, but the control factors are extremely complex. The main reasons are as follows: the abundance and quality of source rocks in Dongpu sag are poor and difficult for preservation, with a large proportion of natural gas in its generated hydrocarbons; a great quantity of hydrocarbon generation and formed traps appear in late Dongying formation, hence there exist a large quantity of oil and gas dispersion and loss; because of little hydrocarbon generation and weak fault activity in the Neogene, the oil and gas migration toward the shallow strata is short of power and channel, and unfavorable for shallow reservoir?forming in this sag Related Articles | Metrics

Characteristics of Karamay Reservoir in Qigu Oilfield in Junggar Basin HU Zongfang, LI Chen, LIAO Wei, HU Qingxiong, LI Rui, SHAO L 2013, 34 (2):  1-1.  Abstract ( 105 )   PDF (300KB) ( 191 )   Save Qigu oilfield is located in the southern margin of Junggar basin with complex terrain and high?steep structures, in which Karamay formation of Triassic belongs to lacustrine shoal?bar sand body sediments with wide distribution area, big thickness and some potentials for hydrocarbon exploration．Because the strata are relatively old and deep?buried in geologic history periods，they have strong diagenesis and compaction, being characterized by seldom primary porosity and developed secondary porosity and fractures. The study shows that the Karamay formation belongs to a porous medium reservoir with super-low porosity and ultra?low permeability, smaller pore throat and high displacement pressure．And it is concluded that this reservoir belongs to a non?conventional and tight sandstone reservoir Related Articles | Metrics

Typical Surface Salt Structure and Deformation Characteristics in Western Kuqa Depression, Tarim Basin CHENG Xiaodao1a,1b, LI Jianghai1a,1b, CHENG Haiyan2, DENG Gang3 2013, 34 (2):  1-1.  Abstract ( 73 )   PDF (300KB) ( 226 )   Save Gypsum salt rocks of the Paleogene occur in the surface outcrops of western Kuqa depression in Tarim basin. This article presents the overall salt structure, deformation and migration characteristics of the salt sheet, salt wall and salt raft by field trip and remote sensing satellite image interpretation. The deformation and migration direction of salt sheet are mainly controlled by gravitational detachment, and its shape is affected by the structural setting. The salt raft is resulted from the gravitational detachment also, and the salt wall is formed by difference loading effect which creates diapir into the surface. At the same time, the weather and topography play an important role in the migration of the gypsum salt rocks, causing the plastic deformation, crawling folds and inner salt folds Related Articles | Metrics

Predicting the Horizontal Well Productivity of Coalbed Methane in Fanzhuang Block in Qinshui Gas Field Using Dimensionless Gas Production Chart SUN Xiaofei, ZHANG YanyuLI Yanjie, CHEN Huijuan, SUN Renyuan 2013, 34 (2):  1-1.  Abstract ( 66 )   PDF (300KB) ( 262 )   Save Numerical simulation method can be used to predict coalbed methane productivity, but it is time?consuming, complicated and poor in practicability. This paper presents the dimensionless coalbed methane production curves (type curves) of the early linear flow and the late radial flow by horizontal well development, studies the influences of 16 geological and production factors on the type curves and proposes a set of new methods for simply and accurately predicting such productivity using the type curves or chart. The result shows that the ratio of horizontal interval length vs. coalbed length in the same direction is the main influencing factor on the curves at the early radial flow stage, while the analytic time, coalbed area and fissure permeability are the main ones for affecting the late radial flow stage. The case study indicates that the result from the type curves or chart is of higher accuracy of prediction, with an error of 17.12%, compared with real daily gas production rate Related Articles | Metrics

Mobility Designing for Polymer Flooding Considering the Viscoelasticity Effect JIANG Ruizhong, WANG Gongchang, YAO Zheng 2013, 34 (2):  1-1.  Abstract ( 61 )   PDF (300KB) ( 255 )   Save The viscoelasticity effect of polymer solution in the seepage process has a great influence on its apparent viscosity, which is why we should consider the viscoelasticity effect in the mobility designing for polymer flooding. Depending on the idea of mobility control and the concept of effective viscosity, this paper analyses the influence of the viscoelasticity effect on the minimum polymer solution mass concentration. The results shows that when the viscoelasticity effect is considered, there will be a critical point in the curve of the minimum of the polymer solution mass concentration with the increasing of shear rate, which obviously differs from the situation where the viscoelasticity effect is not considered. Meanwhile, with the increasing of the relaxation time and at the same shear rate, the minimum mass concentration as required is decreasing, the whole curve moves down, and the longer the relaxation time, the earlier the time when the critical point appears, which means the enhancing of the elasticity effect can reduce the requirements of mobility designing on the polymer solution mass concentration Related Articles | Metrics

Waterflood Development Technology for Deep Heavy Oil Reservoir in Lukeqin Field, Tuha Basin JING Wenbo1,2, ZHANG Na2, SUN Xinhua2, ZHANG Bincheng2, BAI Guojuan2, WANG Weisheng2, LU Lei2, XIN Lijun2 2013, 34 (2):  1-1.  Abstract ( 70 )   PDF (300KB) ( 285 )   Save Lukeqin deep heavy oil reservoir was developed by conventional waterflooding process. Because of high oil/water viscosity ratio, obvious plane and section injection/production contradiction, and water breakthrough was very serious. After using the separated zone development, separated zone water injection, fine water injection and chemical profile control techniques, the plane and section injection/production contradiction has been improved, the waterflood producing degree has been increased from 17.1% in 2008 to 40.9% nowadays, the reservoir pressure has been recovering year by year, and the natural decline rate has been controlled effectively. The mechanism study showed that because of high oil/water viscosity ratio, the mobility ratio was greater than one after water breakthrough. As the water cut increasing, the mobility ratio was raised fast, thus the injected water fingering and breakthrough would be more serious. The study shows that the waterflood response radius is about 100~300 meters. The distance between water breakthrough front and flooded front is about 10~30 meters. The characteristics of water drive of single well or oilfield appear in convex. Medium?high water cut stage is its main production stage Related Articles | Metrics

Comprehensive Analysis of Produced Water Source in Kelameili Volcanic Gas Field, Junggar Basin DONG Jiaxin1, TONG Min1, WANG Bin2, LIU Jinxia3 2013, 34 (2):  1-1.  Abstract ( 60 )   PDF (300KB) ( 228 )   Save Kelameili volcanic gas field belongs to a high porosity and super-low permeability volcanic rock gas pool. It is of strong heterogeneity, vertically and laterally varied lithology and rock facies, unevenly distributed fractures and very complicated relationship between gas and water. The production performance varies from well to well, and the water production characteristics are complex. There exist uncertainties in the produced water source, mechanism and pattern. Based on previous studies, the water production problem in this gas field is researched using related methods available; the produced water source is figured out; the quantitative water production rates of different types are calculated by means of Mcketta?Wehe chart; the classification of produced water source type is conducted, and finally, the influences of different types of produced water source on the gas wells are analyzed in this paper Related Articles | Metrics

Determination of Effective Water Consumption Interval and Its Geologic Implication in Dongying Sag, Bohai Bay Basin XI Fengkun 2013, 34 (2):  1-1.  Abstract ( 56 )   PDF (300KB) ( 178 )   Save Sediment changes may include the water consumption of mineral alteration, the compaction drainage action and the dehydration from clay minerals transformation, etc. during the burial diagenesis and compaction. This paper calculates the water drainage from deep strata compaction and the dehydration from clay minerals transformation in Dongying sag, compares the total water growth rate and the total water consumption at the same depth intervals, and indicates that the balanced depth between them is about 2 500 m, above which the strata are dominated by water increase, below which by water consumption. The water consumption intervals in the deep strata of Dongying sag range from 2 500 m to 3 500 m. Within the effective intervals the reservoir quality can be improved, including enlarging oil?gas storage space, reducing closed fluid pressure, enhancing oil?gas accumulation power, etc. These are all favorable for oil?gas accumulation in this area Related Articles | Metrics

MultiObjective Optimization of FiveSpot Well Spacing Density by Early Polymer Flooding Process LIAN Liming1a,1b, QIN Jishun1a,1b, WANG Qiang1a,1b, LI Junjian1c,2, LI Jinyi3 2013, 34 (2):  1-1.  Abstract ( 57 )   PDF (300KB) ( 173 )   Save Early polymer flooding plays a significant role in the exploration and development of domestic offshore oilfields and the blocks abroad. The former optimization methods with single factor are not available in view of complexity of the current oilfield geologic status. This paper establishes the multi?objective optimization model for study of cumulative production and net present value (NPV) rate by early polymer flooding process, through theoretic methods and empirical regression analysis, in which five?spot well pattern is taken as studied object, comprehensively considering reservoir and economy dual objectives, with limitations of polymer solution concentration, injection capacity, productivity and production life, etc. The rational well spacing density is optimized by fitness function method and applied to the oilfield blocks. The results from comparison with the single objective optimization show that the multi?objective optimization method is better in adaptability and more suitable for five?spot well pattern study by early polymer flooding process Related Articles | Metrics

Application of Heterogeneity Index to Study of BlockA Reservoir in Dalugou Area of Jing’an Oilfield, Ordos Basin LIANG Liwen1a,1b, KUANG Lixiong1b, JING Xiaojun2, SHI Defeng1b, HUANG Wenjun1b 2013, 34 (2):  1-1.  Abstract ( 75 )   PDF (300KB) ( 222 )   Save The reservoir heterogeneity index and grey association analysis were used to study the reservoir heterogeneity in Chang?2 clastic reservoir of the Triassic Yangchang formation of Block?A in Dalugou area of Jing’an oilfield in Ordos basin. The result shows that the Chang?2 reservoir of Block?A is totally good in quality, the reservoir heterogeneity in the east area is relatively weak than the northwest and southwest areas. The heterogeneity trend gradually becomes stronger from the east to the west. The main controlling factors are the interlayers and sedimentary microfacies. The quicker response area after water injection could be the favorable area in remaining oil distribution, where the regional heterogeneity index ranges from 0.65 to 0.75. The study also indicates that the gray association analysis is simple and fast in calculation to more accurately give the weight coefficients of each parameter. The reservoir heterogeneity index can be used to overcome the lack of a single factor characterization of reservoir heterogeneity. Combined with the Gaussian random function simulation, a quantitative characterization of the reservoir heterogeneity is also realized Related Articles | Metrics

Application of Real Options to Economic Evaluation of Low Permeability Oilfield Development Project DENG Yuhui 2013, 34 (2):  1-1.  Abstract ( 58 )   PDF (300KB) ( 327 )   Save There are a lot of uncertain factors in the low permeability oilfield development project. Its investment is of irreversibility and delayability. The decision?maker has some flexibility in choosing development time. These features allow the project to be of typical real options property. Based on Black?Scholes model, this article establishes the real options method suitable for such a project, conducts case study and makes a comparison with net present value (NPV) method. However, the opposite results are obtained by these two methods. It is concluded that the reason is that using NPV method tends to underestimating the value of the project Related Articles | Metrics

Analysis on Application of Reverse Time Migration to Complex Geologic Structures ZHAO Lingzhi1,2, WANG Kebin2, LI Daoshan2, ZHANG Jianzhong1 2013, 34 (2):  1-1.  Abstract ( 71 )   PDF (300KB) ( 281 )   Save Using the prestack depth migration technology based on integral method of ray theory to areas with complex geologic structures (e.g. salt dome, overthrust nappe, etc.) and severe lateral velocity variation tends to influencing exact recognition of underground geologic bodies due to seismic imaging condition restrictions. This paper analyzes the imaging theory and its merits of reverse time migration (RTM) based on theory of wave, and gets better imaging effects in practice. In order to increase the RTM adaptability, a variety of seismic data are selected to test. The result shows that RTM is an effective technology for improving the imaging of salt dome and structures under overthrust nappe. In areas with little change of velocity and uncomplicated wave field, using RTM can effectively maintain the amplitude of seismic reflection signals, although the imaging improvement obtained by RTM is not obvious Related Articles | Metrics

Using Spectral Decomposition Technology and Seismic Peak Attribute Analysis for Prediction of Thin Sandstone Reservoir XIONG Ran, ZHAO Jilong, HOU Gangfu 2013, 34 (2):  1-1.  Abstract ( 67 )   PDF (300KB) ( 235 )   Save This paper presents the theory and method for spectral decomposition, analyzes thin sandstone reservoir with forward modeling and then generalizes the seismic reflection features of the reservoirs in different sand thickness. The reservoir lithology and physical property studies are based on the drilling cores, logging curves and seismic attributes, establishing the empirical formulae for prediction of the thin sandstone reservoirs by seismic attribute optimizing selection, statistics and regression in time domain and spectral decomposition in frequency domain. It is recognized that there are two advantageous zones with thin sandstone reservoirs in studied area. The applied results show that such a method is more effective for recognition of thin sandstone reservoirs Related Articles | Metrics

Advances of Mechanism Study of Fracture Networks Formed by Simultaneous Fracturin Process LI Xiaogang1, LUO Dan1, LI Yu1, ZHANG Yaming2 2013, 34 (2):  1-1.  Abstract ( 74 )   PDF (300KB) ( 338 )   Save Simultaneous fracturing process is a new technique for reservoir improvement of unconventional gas, such as shale gas and coal bed methane. Revealing the mechanical mechanism of fracture propagation is the basis of optimizing treatment parameters. The study shows that multi?fracture simultaneous propagation may alter the stress field and these fractures can interact with natural fractures. Both of them co-determine the pattern of fracture network during the fracturing process. Fracture network engineering (FNE) is the best method for study of such a model for fractures propagation at present. To achieve complex fracture networks by inducing in?situ stress field, the parameters such as number of fractures, distance between fractures, net pressure and the geometry of hydraulic fractures should be optimized Related Articles | Metrics

Application of Multistage Acid Fracturing Technology for Horizontal Well to UltraDeep Fractured Carbonate Reservoirs ZHANG Bo1,2, XUE Chengjin1, ZHOU Linbo1, ZHANG Ye2,3 2013, 34 (2):  1-1.  Abstract ( 81 )   PDF (300KB) ( 264 )   Save The Ordovician carbonate reservoir in Tarim oilfield is dominated by fractures and solution pores and cavities and characterized by ultra?deep, high pressure and high temperature, of which the most fractures with medium?high angle are as both reservoir spaces and the main flow channels. But since such a reservoir is of low pore?throat coordination and poor connectivity, acid fracturing process has to be needed to build its productivity. The main factors affecting the effect of acid fracturing include the selection of acid fracturing process for the long openhole interval and that the acid?etching fractures can communicate the effective fracture?cave reservoir or not. For these reasons, this paper conducts such parameters optimizations as acid?etching fracture length, fluid conductivity, stimulation scale, prepad fluid ratio and expelling amount, etc., and then selects the fracturing and acid liquids to form a differentiated and multistage acid fracturing optimization design scheme. The field application indicates that the designed parameters are reasonable and effective, and the multi?stage acid fracturing technology is suitable for stimulation of the ultra?deep fractured carbonate reservoirs Related Articles | Metrics

Quantitative Elimination Method for Gas Measured Value in Respons to OilEmulsion Drilling Fluid YANG Mingqing1,2, WANG Chengbiao1, WANG Yin3, FU Lixia 2013, 34 (2):  1-1.  Abstract ( 65 )   PDF (300KB) ( 220 )   Save During horizontal well drilling process, people often mix oil or organic additives into drilling fluid, which may have interference on gas measured indication and impact on the discovery and evaluation of oil and gas shows. The traditional solution is deducting part of the gas measured values based on experience, and regarding the deducting part as the gas measured values in response to oil?emulsion drilling fluid, which does not realize the proper measurement or quantitative elimination of strata oil?gas indication value. The relative content of each component is different between gas measured values from the strata and the oil?emulsion drilling fluid, by which such a proper quantitative elimination that may objectively reflect in?situ hydrocarbon?bearing information can be made through calculations. This approach has been successfully applied to Shengli oilfield, Zhongyuan oilfield, northeastern Sichuan and Xinjiang, etc, without increasing costs and complex calculations, thus can be widespread for use in gas logging with mixed oil?emulsion drilling fluids Related Articles | Metrics

The Science Research Frontier of Petroleum Geology ZHANG Zhiyi, XIA Bing, ZHU Ruijing, ZHANG Yanni 2013, 34 (2):  1-1.  Abstract ( 54 )   PDF (300KB) ( 469 )   Save Plate tectonics theory is not appropriate for continental geology. New understanding of the earth exhaust effect gives a bright way to the earth dynamics study and opens a broad space for the earth science research. Theory of deep origin of oil has well developed and several new research frontiers have appeared. Many new research results, such as experiment or researches to the inorganic synthesis of hydrocarbons, structure knot, ring?shaped structure, the basement of oil?bearing basin and inexhaustible nature of oil/gas resources, are presented in this paper. All these researches proved that tectonic movements of the earth crust tectonics controlled oil/gas formation and distribution. Oil and gas were the products of the earth evolution at a certain stage. The science research frontier of petroleum geology lets us get new ideas from practices to form new theory. Using such new theories to guide oil/gas exploration and development will play an unprecedented role and has great potentials in development Related Articles | Metrics

Wettability of Underground RocksReply to Mr LI Zhengke LI Chuanliang 2013, 34 (2):  1-1.  Abstract ( 100 )   PDF (300KB) ( 425 )   Save Main minerals of rocks are all polar materials. The polarity of formation water is stronger than that of oil, so underground rocks are water?wet and there are no oil?wet rocks underground. The water?wettability of rocks provides the precondition of migration of oil and gas from source rock to trap. Oil?wet rocks will disperse the oil and gas during migration, and can’t allow the hydrocarbon accumulation to be completed at all. Relative permeability curves measured at laboratory indicate the water?wettability of rocks clearly. The normal distribution of reservoir pressure is also an evidence of water?wettablity of underground rocks. Oil?wet rocks won’t prohibit the migration of oil and gas as a seal rock but allow oil and gas to be dispersed through them. The oil?wettability of rocks measured at laboratory does not reflect the underground conditions, so it is meaningless Related Articles | Metrics