2012 Vol. 34, No. 4

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2012, 34(4)
Abstract(1405) PDF-CN(913)
Abstract:
Deformation of Chuxiong Foreland Basin
Ding Daogui, Pan Wenlei, Huang Jiwen
2012, 34(4): 345-351. doi: 10.11781/sysydz201204345
Abstract(1841) PDF-CN(1498)
Abstract:
Locating in the southwestern margin of the Yangtze Plate,the Chuxiong Basin in Yunnan Province is a Mesozoic foreland basin formed in the northeast of the Ailaoshan-Honghe Collisional Orogenic Belt after the closing of the Jinshajiang-Mojiang Oceans of Paleo-Tethys during the Middle Triassic.The basin has experienced 2 stages of tectonic deformations.In stage Ⅰ,from the Late Cretaceous to Eocene,the Ailaoshan-Honghe Collisional Orogenic Belt uplifted and thrusted from south to north to the Chuxiong Foreland Basin,resulting in progressive inversion and fold deformation belt with decreasing deformation strength as well as sinistral strike-slip fault by the side of nappe.In stage Ⅱ,from the end of Oligocene to Miocene,as the Indian Plate collided with the Eurasian Plate and kept wedging and squeezing,the axial of the Chuxiong Basin changed from EW to NW;meanwhile,fracture deformations such as right-lateral movement and simple shear took place,and the thrust-fold deformation from SW to NE happened.
Organic matter reservoir space of shale in Dongying Sag, Bohai Bay Basin
Zhu Rifang, Zhang Linye, Li Juyuan, Li Zheng, Liu Qing, Wang Xiuhong, Wang Ru, Wang Juan
2012, 34(4): 352-356. doi: 10.11781/sysydz201204352
Abstract(2386) PDF-CN(1659)
Abstract:
The contribution of hydrocarbon conversion to reservoir space of the shale in the lower Es3 and the upper Es4 in the Dongying Sag of the Bohai Bay Basin is discussed according to the volume change of kerogen in the process of hydrocarbon generation.It is proposed that the two sets of shale is of high brittle mineral content,and the mechanic property of the shale changes obviously in the depth intervals of 2 000-3 000 m and the shale becomes more brittle.There are good preservation conditions for pores within organic matter below 3 000 m,and the porosities within organic matter of the two sets of shale with different organic matter abundance in different buried depth are further discussed.It is shown that the porosities within organic matter are very limited for the shale with low abundance of organic matter(TOC content 2%);however,for the shale with higher abundance of organic matter(TOC content 4%),the porosities formed during hydrocarbon generation process can reach 4% in the higher mature stage.In the Dongying Sag,the upper Es4 section has a higher maturity,and the porosities within organic matter are widely developed during hydrocarbon generation in the deep depression.For comparison,it has a much lower organic maturity and porosity,and only locally developed in the lower Es3.
Structural features of unconformity and hydrocarbon accumulation on top of Mesozoic, southern slope of Huimin Sag, Jiyang Depression, Bohai Bay Basin
Wu Kongyou, Bai Sen, Cui Shiling
2012, 34(4): 357-361. doi: 10.11781/sysydz201204357
Abstract(2783) PDF-CN(1066)
Abstract:
In the southern slope of the Huimin Sag of the Jiyang Depression in the Bohai Bay Basin,3 types of unconformity were found on the top of Mesozoic,including truncation,onlap and parallel ones.The unconformities were divided into 3 layers vertically,including basal conglomerate or transgressed sand body,weathered clay and eluvial zone.Each layer has its own logging response characteristics and identification marks.Due to the different lithology of each layer,7 patterns of lithology configuration were formed.According to core observation and sample test,secondary pores generated in the eluvial zone of unconformity in Qudi area.The unconformity served as the pathway for petroleum migration,and also provided the space for accumulation.The studies of the relationship between unconformity and petroleum accumulation have important academic and practical significances for subtle reservoir exploration in the Huimin Sag.
Tectonic deformation features from Late Indosinian to Yanshanian in southern Guizhou
Wang Jinyi, Peng Jinning, Wang Yanqing, Liu Guangxiang, Gao Lin
2012, 34(4): 362-367. doi: 10.11781/sysydz201204362
Abstract(2232) PDF-CN(1112)
Abstract:
The tectonic deformations in the southern Guizhou were zoned obviously.To the north of Guiyang-Guiding-Sandu,fault belts distributed in NS direction.The studies of fluid inclusion showed that the present fault belts were active from the late Indosinian to Yanshanian and their tectonic deformation features were in accordance with the general law of progressive(attenuated) deformation caused by the nappe of Xuefeng Mountain from east to west.The rock samples from the fault belts confirmed that rocks were influenced by the squeeze and twist effect from the upper to the lower disk.The faults were compressive.The fault belts were brittle and some were ductile.To the south of Guiyang-Guiding-Sandu,the thrusting of Xuefeng Mountain from east to west led to medium-weak or weak deformations and a gentle anticlinal tectonic framework in NE direction was formed under the influence of Yaziluo squeeze and strike-slip belt.Big difference of stress field existed between the northeast and the southwest of the study area during tectonic evolution.The Anshun and Changshun Sags in the weak deformation belt might be favorable targets for petroleum migration and accumulation.
Multi-stage structural deformation features and hydrocarbon accumulation in faulted basin: a case study in Nanbeier Sag of Hailar-Tamtsag Basin
Zhang Junlong, Meng Qi'an, Qi Jiafu
2012, 34(4): 368-375. doi: 10.11781/sysydz201204368
Abstract(2222) PDF-CN(1060)
Abstract:
The control of structural style on petroleum was analyzed through studying the relationship between multi-stage tectonic deformation features and the main factors controlling hydrocarbon accumulation,such as sedimentary filling type,hydrocarbon source rock generation feature,trap type and pathway system,etc.The controlling effect of structural style on petroleum in basin and depression was analyzed.From the aspect of basin level,structural deformations from non-rotating graben/rotating half graben,rolling half graben,duplex half graben,to slip half graben generated in the Nanbeier Sag during tectonic evolution.Various sag structures determined the filling types of sedimentary system and the distribution features of sand body,further influenced the generation and distribution of source rock,resulted in various hydrocarbon generation and accumulation assemblages in different formations,and finally controlled the superimposed composition of various reservoir types.Tectonic styles were classified into 3 stages,3 big types(rift type during chasmic stage,extensional-twist type during fault and depression stage,and torsional reversed type during inversion stage) and 18 types.Compressional structures of inversion stage were advantage points in secondary oil reservoirs.The structural styles of faulted-depression and inversion stage constructed multiple types of fault-sand body pathway system.The deformation features of fault basin controlled the key elements for hydrocarbon generation,reserve,trap and migration,and further determined the distribution of oil and gas.
Tectonic properties and post-reformation in Late Triassic, Ordos Basin
Li Xiangbo, Liu Huaqing, Wan Yanrong, Feng Ming, Wei Lihua
2012, 34(4): 376-382. doi: 10.11781/sysydz201204376
Abstract(2405) PDF-CN(1240)
Abstract:
Based on the analysis of over 60 outcrops and over 300 important exploratory wells,combined with previous studies,applying the principles of plate tectonics and geodynamics,it was discussed in this paper the tectonic environment,basin property and late-stage reformation of the Ordos Basin during the Late Triassic.Conclusions were made as followed.1) During the Late Triassic,the main part of the basin was a cratonic depre-ssion while the southern(southwestern) margin was a foreland basin and the northwestern margin was a rift basin.This setup might be related to the special geological boundary conditions of the basin and the special force way during the Late Triassic.2) Prototype basin experienced 4 stages of various late-stage reformations,which caused basin area reducing by about 300 000 km2.3) Based on the distribution of residual source rocks,except for the inner part of the basin and the foot of the thrust belt in the western margin,the Liupanshan Basin to the west and the Weihe Basin to the south of the Ordos Basin are also worth exploring in the future.
Sequence stratigraphy of Lower Ganchaigou Formation in Yuejin Slope, southwestern Qaidam Basin
Wang Bo, Xue Jianqin, Cui Xiaosong, Cao Tong, Ding Xuguangi, Guo Shaobin
2012, 34(4): 383-387. doi: 10.11781/sysydz201204383
Abstract(2256) PDF-CN(970)
Abstract:
Sequence stratigraphic studies with high resolution were carried out in the Lower Ganchaigou Formation in the Yuejin Slope of the Qaidam Basin by means of drilling/logging,seismic and natural gamma ray spectrometry logging methods.The Lower Ganchaigou Formation was divided into 2 sections vertically.9 sequence boundaries and 8 fourth-order sequences were identified.Based on core observation,the Yuejin Slope was a braided-river delta,and the study area was mainly of braided-river delta front facies.Combined with the studies of sand body distribution,structure and seismic inversion,2 possible favorable zones of lithologic trap were predicted in sequence Ⅲ of the Lower Ganchaigou Formation.
Mesozoic tectonic framework and basin distribution characteristics of northern margin of South China Sea
Yi Hai, Zhang Li, Lin Zhen
2012, 34(4): 388-394. doi: 10.11781/sysydz201204388
Abstract(2135) PDF-CN(1389)
Abstract:
During the tectonic history of the South China Plate,continental crust gradually accreted and crustal structure became more and more complicated.In the northern margin of the South China Sea,tectonic framework was separated by regional basement faults and was characterized by a north-south zoning and west-east blocking distribution during Mesozoic.The major Mesozoic sedimentary basins in the northern margin of the South China Sea were located at the centeral-eastern Guangdong subsiding belt and the Dongsha-GaoXiong continental margin subsiding belt.In the Dongsha-Gaoxiong continental margin subsiding belt,there were three Mesozoic continental margin basins including the Chaoshan Basin,the Gaoxiong Basin and the Bijia Basin,and their total area was about 6.7×104km2.The Upper Triassic and Cretaceous strata were deposited with giant thickness in these basins and had good oil and gas geological conditions.The Dongsha-Gaoxiong continental margin subsiding belt is a favorable zone for the Mesozoic petroleum exploration in the future.
Sedimentary characteristics and favorable reservoir prediction of Longtan Formation in Huangqiao area, Jiangsu Province
Li Jianqing, Pu Renhai, Wu Yue, Tian Yuanyuan
2012, 34(4): 395-399. doi: 10.11781/sysydz201204395
Abstract(2539) PDF-CN(1091)
Abstract:
Effected by the fold and uplift of the Indosinian movement,the Longtan Formation in the Lower Yangtze area was locally eroded.Drillings revealed that the lateral variation of the residual Longtan Formation sandstones had changed obviously.The comprehensive analysis of cores,log curves and 3D seismic interpretations showed that the Longtan Formation was a delta front sedimentary sequence,with the characteristics of coarsening-upward,and the types of sand body were mainly frontal sheet sand and distributary channel sand in Huangqiao area,Jiangsu Province.The results of logging constrained impedance inversion and porosity inversion showed that high-impedance sandstones spread in three delta front flower-like bodies in the plane.The average porosity of the Longtan Formation sandstones ranged from 4% to 10%,and became bigger as the present depth increasing.
Occurrence state and production mechanism of formation water in tight sandstone reservoirs of Sulige area, Ordos Basin
Wang Xiaomei, Zhao Jingzhou, Liu Xinshe
2012, 34(4): 400-405. doi: 10.11781/sysydz201204400
Abstract(2648) PDF-CN(1134)
Abstract:
The Sulige gas field in the Ordos Basin is the largest unconventional continuous tight sandstone reservoir in China.There are many water-producing gas wells in the Upper Paleozoic strata in the west and the north of Sulige region,where the reservoir has no unitive gas-water interface.The intrinsic rules of gas-water distribution are complicated in this area.Based on the dynamics of hydrocarbon accumulation in tight sandstone,integrating oil and gas accumulation elements and reservoir present microscopic pore structure and fluid flow mechanism,the occurrence state and production mechanism of formation water in Sulige region have been discussed in this paper.It has been showed that the main reason for complicated gas-water distribution is the difference between hydrocarbon generation expansive force and capillary pressure.The occurrence state of formation water in this area behaves 3 types,i.e.irreducible water,capillary water and free water.The irreducible water is basically located in the high gas generation intensity area in the east of Sulige region,where the testing gas wells are mainly gas-producing ones.The capillary water is normally located in the low gas generation intensity area in the west and the north of Sulige region,where the testing gas wells are mainly gas/water-producing ones.The free water is sporadically located in the area.
New thoughts of continental gas exploration in Western Sichuan Depression
Wang Peng, Li Rui, Liu Ye
2012, 34(4): 406-411. doi: 10.11781/sysydz201204406
Abstract(2324) PDF-CN(970)
Abstract:
Located on the edge of Longmengshan thrust-napped belt,the western Sichuan Depression from the Upper Triassic to Jurassic is a set of continental tight-super tight gas-bearing clasolite.Long-term exploration has proven structures and various types of composite traps.Applying the theory of continuous gas reservoir to analyze the target zone,it has been found out that Jurassic in the western Sichuan is a "distal" gas pool and does not have continuous gas reservoir forming conditions.The Xujiahe Formation possesses accumulation conditions and characteristics of continuous gas reservoir.This is particularly true for T3x5 and part of T3x4 which are characterized by shallow burial depth,well-developed pelite,high organic richness,high maturity,large amount of gas generation and general contact with sandstone.Therefore,with the advantages of exploration for both shale gas and tight gas,they possess large exploration potential and are the most practical development areas under current economical and technical conditions.In view of the high exploration degree of the Xujiahe Formation,the enrichment regulation study for continuous gas reservoir is carried out by the combined prediction of geology-logging-seismic technologies,especially with the high-precision 3D seismic data.The application of new techniques such as pre-stack reservoir,fracture gas-bearing property and advanced engineering technologies of drilling,reservoir stimulation and protection is expected to achieve significant breakthroughs.
Formation mechanism of high-quality reservoir of calcarenaceous sandstone in fourth member of Xujiahe Formation, Fenggu area, Western Sichuan Depression
Luo Wenjun, Peng Jun, Zeng Xiaoying, Liu Huan, Xiao Yan, Tang Yong, Yang Xiaochen
2012, 34(4): 412-416. doi: 10.11781/sysydz201204412
Abstract(2412) PDF-CN(975)
Abstract:
The calcarenaceous sandstone reservoir in the fourth member of the Xujiahe Formation in Fenggu area of the Western Sichuan Depression is a typical tight sandstone reservoir characterized by high content of carbonate debris(accounting for over 90% in total debris),well-developed carbonate cementation,low porosity and low permeability;however,under the background of general dense,favorable reservoirs also develop in some intervals with the porosity of over 12%.The analysis of reservoir feature and diagenesis has indicated that the differential cementation of reservoir calcite is the key for the preservation of primary pore in high-quality reservoir.Then disruption communicates reservoir and acid fluid of hydrocarbon emplacement,improving reservoir quality.The later hydrocarbon charge protects reservoir porosity.
Geochemical characteristics and origin of natural gas in Lishu Fault Depression, Songliao Basin
Zhang Jun, Zhao Hongjing, Zhang Min
2012, 34(4): 417-421. doi: 10.11781/sysydz201204417
Abstract(2408) PDF-CN(911)
Abstract:
Based on the analyses of natural gases from three gas fields and three oil fields,the composition and plane distribution of natural gases in the Lishu Fault Depression of the Songliao Basin were discussed and the genetic types of gas were identified.Natural gas in the Lishu Fault Depression contains significant alkane gases and a little nonhydrocarbon gases,especially CO2.Alkane gases and CO2 were organic genesis and there were three genetic types of alkane gases in the Lishu Fault Depression.The first type was mixed by oil-type gases with different maturities,mainly located in Pijia gas field,Bawu and Siwujia oil fields,with partly reserved order of δ13C.The second type was coal gases with high and over maturity,located in Gujiazi gas field and Xinli oil field,with reversed order of δ13C.The third type was mixed by oil-type gas and coal gas,located in Houwujiahu gas field.
Separation of diastereoisomers of acyclic isoprenoid alkanes by GC-MS and optimization of operation conditions
Wu Yingqin, Wang Yongli, Lei Tianzhu, Wang Youxiao, Xia Yanqing
2012, 34(4): 422-426. doi: 10.11781/sysydz201204422
Abstract(2203) PDF-CN(1001)
Abstract:
The separation of diastereoisomers of acyclic isoprenoid alkanes on HP-5 columns was firstly reported by gas chromatography and mass spectrometry(GC-MS).The biomarkers of saturated hydrocarbons from coal samples of the Junggar Basin and crude oils of Gudao area were determined,and iC18(2,6,10-trimethyl pentadecane),Pr(2,6,10,14-tetramethyl pentadecane),Ph(2,6,10,14-tetramethyl hexadecane) and their diastereoisomers were identified from coal samples and crude oils.The effects of type and length of chromatographic column and temperature programming on the separation of diastereoisomers of acyclic isoprenoid alkanes were investigated.The most favorable separation conditions were concluded.The diastereoisomers were separated from nor-pristane,Pr and Ph,and the maximal resolution factors of Pr and Ph are 0.7,0.9,respectively.
Characteristics and hydrocarbon-generating potential of Carboniferous source rock in Tacheng Basin
Jiang Yiqin, Gao Gang, Liu Guangdi, Wang Xulong, Pei Lixin, Xiang Baoli, Tang Yong
2012, 34(4): 427-431. doi: 10.11781/sysydz201204427
Abstract(2679) PDF-CN(982)
Abstract:
Based on the analyses of generation and organic geochemical characteristics of outcrops in the Tacheng Basin and source rocks from well Tacan 1,the hydrocarbon-generating potential of the Carboniferous source rocks was discussed.According to the lithology and organic abundance of source rocks,mudstones were good source rocks while carbonaceous mudstones and coals were also favorable.The mudstones in the Upper Carboniferous were generally more favorable than those in the Lower Carboniferous.The organic material types of source rocks were mainly humus ones with gas-generating feature.Source rock evolution had entered the high-mature and over-mature stages,but there still existed residual hydrocarbon-generating capacity.Studies should be focused on the main distribution areas of source rocks,the relationship between hydrocarbon generation and basin evolutions histories,and the history of accumulation.
Application of quantitative grain fluorescence techniques in analysis of hydrocarbon charge history in Dabei 1 gas reservoir, Kuqa Depression, Tarim Basin
Xing Enyuan, Pang Xiongqi, Xiao Zhongyao, Jiang Zhenxue, Zhang Yongsheng, Guo Jigang
2012, 34(4): 432-437. doi: 10.11781/sysydz201204432
Abstract(2283) PDF-CN(848)
Abstract:
For the study of charge history and distribution law of oil and gas in the Dabei 1 tight gas reservoir in the Kuqa Depression of the Tarim Basin,36 sandstone samples collected from wells DB 101,DB 103 and DB 2 were tested with quantitative grain fluorescence techniques.The results showed that wells DB 101 and DB 2 located in the same palaeo-trap while well DB 103 located in a separate palaeo-trap.Oils distributed in layers in those traps.The present water layers in well DB 101 were palaeo-hydrocarbon migration paths.Under the current gas-water interface in well DB 103,there might be residual oil layers,and the real gas-water interface was deeper.Part of the palaeo-oil reservoir in well DB 2 was destroyed in later stage.The distribution and evolution of palaeo-oil reservoirs played an important role in the present distribution of oil and gas accumulation.
Physical simulation of sand lens reservoir formation in continental rifted basin
Zhao Weiwei, Li Delu, Cha Ming
2012, 34(4): 438-444. doi: 10.11781/sysydz201204438
Abstract(2552) PDF-CN(960)
Abstract:
Sand lens reservoir is the main type of lithologic reservoirs for increasing reserves in continental rifted basin,but its hydrocarbon migration process and mechanism still remain discussing.A lithologic trap model has been established to simulate hydrocarbon migration and accumulation in sand lens reservoir.The differences in the process and mechanism of hydrocarbon accumulation in sand lens reservoir under different geologic conditions have been confirmed.Episodic accumulation is outstanding for high efficiency and high speed.Hydrocarbon-source conditions,transport conditions,the distance between source rocks and reservoir rocks as well as sand body properties control the formation of sand lens reservoir.
Thermal simulation of Silurian bituminous sandstone and its significance of hydrocarbon supply in northern Tarim Basin
Huang Jiwen, Gu Yi, Chen Qianglu, Shao Zhibing
2012, 34(4): 445-450. doi: 10.11781/sysydz201204445
Abstract(2503) PDF-CN(922)
Abstract:
To study the hydrocarbon generation potential of the Silurian bituminous sandstone in the northern Tarim Basin,two sets of experiment program were carried out using artificial and geologic samples respectively.According to the yielding rate and product composition under different experiment temperatures,the hydrocarbon generation process of the Silurian bituminous sandstone was divided into 3 stages including evaporative fractionation oil-and-gas expulsion stage(with the simulative temperature of 100-300℃,equivalent to Ro<0.9%),cracking oil-and-gas expulsion stage(with the simulative temperature of 325-400℃,equivalent to 0.9%<Ro<1.8%),and cracking gas expulsion stage(with the simulative temperature over 400℃,equivalent to Ro>2.0%).According to the actual depth and maturity of the Silurian bituminous sandstone in the northern Tarim Basin,those sandstones during the cracking oil-and-gas expulsion stage were buried over 6 000 m deep and mainly located in the western Shaya and Halahatang areas.Through resource estimation,although the bituminous sandstones could not provide enough hydrocarbons for accumulation in large scale,they were the most important auxiliary regenerative hydrocarbon source rocks in the northern Tarim Basin.
Experiment of dolomite dissolution in stress state and its geologic significance
Luo Kaiping, Fan Ming, Liu Yunli, Han Yu
2012, 34(4): 451-453. doi: 10.11781/sysydz201204451
Abstract(2320) PDF-CN(882)
Abstract:
The generation of dolomite reservoir mainly depends on diagenetic deformation,among which dissolution is the most important.Dolomite reservoirs in the Changxing and Feixianguan Formations of the northeastern Sichuan Basin were studied.The relationship between dissolution pores and structural features such as cracks or micro-cracks in reservoirs were analyzed.The experiment of dolomite dissolution in stress state was carried out and the influences of cracks or micro-cracks on dolomite dissolution were discussed.It was concluded that the development of cracks was favorable for dissolution,and the burial dissolution under structural deformation was the most important deformation effect for dolomite reservoir.
Experimental study on physical properties after flooding under high temperature and high pressure condition: taking reservoir T_Ⅰ of Tarim Lunnan Oil Field as an example
Guo Ping, Xu Yunlin, Shi Mei, Zhang Juan, Lian Zhanggui
2012, 34(4): 454-458. doi: 10.11781/sysydz201204454
Abstract(2047) PDF-CN(908)
Abstract:
The T reservoir of the Lunnan Oil Field in the Tarim Basin has over 20 years' development history.In recent years,the application situation of water flooding was researched,but was not in formation condition.In this paper,in order to figure out oil and water seepage law,and to study the reservoir alternations of micro-pore structure and wettability after long-term water flooding,we conducted a water flooding modeling experiment under high temperature and high pressure using fluid and core from this oil field.The experimental results showed that the reduction extent of porosity and permeability of cores increased as water flooding increased,and throats' sorting became weaker.Wettability also increased as water flooding increased.The irreducible water saturation and irreducible oil saturation values on core relative permeability curve rose while the water relative permeability under irreducible oil saturation dropped.Oil displacement efficiency decreased.High-capacity channels were not formed after water flooding.The main reasons for early water breakthrough might be plane and longitudinal heterogeneity.