2011 Vol. 33, No. 4

Display Method:
2011, 33(4)
Abstract:
2011, 33(4): 320-320. doi: 10.11781/sysydz201104320
Abstract:
Exploration practice and experience of Tahe giant oil-and-gas field, Tarim Basin
Zhai Xiaoxian
2011, 33(4): 323-331. doi: 10.11781/sysydz201104323
Abstract(3718) PDF-CN(1247)
Abstract:
Successes and failures of petroleum exploration in the Tahe giant oil-and-gas field have been summarized in this paper.It has been concluded that both the discovery of the oilfield and the following breakthroughs come from theory development and technique innovation.Development of exploration theory in the Tahe giant oil-and-gas field has enriched the accumulation theory of Paleozoic marine carbonate rock in the Tarim Basin.
Basic features of petroleum exploration development in mature exploration area
Guo Yuanling
2011, 33(4): 332-335. doi: 10.11781/sysydz201104332
Abstract(1868) PDF-CN(995)
Abstract:
The cooperation of exploration processes of several accumulation systems leads to the periodicity of petroleum-bearing basin exploration.When reserve growth continues between different accumulation systems,exploration develops.Preliminary exploration,rational reserve sequence and resource replacing capacity are required so as to make progress in mature exploration region.An exploration unit is the smallest geologic unit in which exploration can be arranged and carried out.The subdivision of exploration unit is the symbol for deepen-ing development in mature region.New ideas are important for new discoveries.The adequate protection of resources,the stable development of exploration teams and the harmony of inner and outer environments are the keys for the constant increasing of reserves.The studies of mature region exploration may provide guides for exploration arrangements and strategic researches.
Several discussions of sealing capacity studies of caprock
Yuan Yusong, Fan Ming, Liu Weixin, Li Shuangjian, Wo Yujing
2011, 33(4): 336-340. doi: 10.11781/sysydz201104336
Abstract(1681) PDF-CN(1238)
Abstract:
It is discussed in this paper the sealing capacity of highly mature mudstone,the relationship between caprock thickness and sealing capacity,the microcosmic sealing mechanism of caprock and the quantitative evaluation of sealing capacity evolution.Highly mature mudstones may have good sealing capacity if they were not destroyed during tectonic deformation.The height of sealed natural gas column is closely related to caprock thickness.Capillary sealing is the most common sealing mechanism,while hydrocarbon concentration sealing is not very common.The dynamic evolution of sealing capacity of mudstone may be divided into 2 stages:formation and reformation.Quantitative reconstruction can be carried out according to the 2 stages.As to the formation stage,porosity-displacement pressure method is introduced.Permeability-displacement pressure and/or OCR method are used in studies of the reformation stage.
Sedimentary facies analyses based on well drilling and logging data from Devonian Kerziertag Formation in Bashitop area of Tarim Basin
Yang Ruizhao, Wang Ping, Zhang Zhiqiang, Chen Shuyang, Liu Wei
2011, 33(4): 341-347. doi: 10.11781/sysydz201104341
Abstract(2718) PDF-CN(1106)
Abstract:
Sedimentary facies of the Devonian Kerziertag Formation in Bashitop area of the Tarim Basin have been studied with drilling and logging sedimentary facies analysis method.The Kerziertag Formation in the study area was formed in wave-dominated barrier-free clastic littoral depositional environment.The foreshore subfacies include 3 microfacies such as beach,groove and sand dam.The petroleum shows of actual drilling in single well have indicated that the beach microfacies are the most abundant in petroleum,and the coastal sand dam near to beach takes the second place.As to the coastal sand dam in the upper near shore,it interbeds with the lower near shore and is also favorable for petroleum preservation even though its physical property is poor.
Discovery and significance of Qrebake and Yijianfang Fomations of Ordovician in well GL1, Tarim Basin
Cai Xiyao, Qian Yixiong, Chen Qianglu, Chen Yue, You Donghua, Yang Yufang, Zhao Lina
2011, 33(4): 348-352. doi: 10.11781/sysydz201104348
Abstract(2527) PDF-CN(1099)
Abstract:
The Qrebake Formation of the Upper Ordovician and the Yijianfang Formation of the Middle Ordovician have been found for the first time in well GL1 of the Guchengx? Uplift of the Tarim Basin.They have the same lithologic association,electrical property and conodont zone as name-sections and typical wells in the Tahe and Shaxi regions.Unique stratigraphic sequence has been found in the study region.According to studies of petrology,sedimentary structure and palaeontology,the Qrebake Formation belongs to slope facies sediments.The Qrebake and the Yijianfang Formations distribute stably in the west of Guchengx? Uplift and are favorable for trace comparison on seismic profiles.The 2 formations mainly locate in the lower positions of uplift margin and the intermediate zone of slope.On the uplift,sedimentary gap and degradation vacuity are found respectively.The studies may help the stratigraphic correlation of Ordovician and the analyses of sedimentary environment and tectonic movement in the Guchengx? Uplift,the Katkke uplift,the Tangusbas Sag,and the Tahe and Shaxi regions.
Sedimentary facies of Carboniferous carbonate rock in Bashitop Oil Field, Tarim Basin
Yan Jixin, Zhao Xisen, He Yunfeng, Zhao Xuebin, Wei Shaohua, Zhou Gang
2011, 33(4): 353-358. doi: 10.11781/sysydz201104353
Abstract(3010) PDF-CN(951)
Abstract:
In Bashitop area of the Tarim Basin,from bottom to top,Carboniferous can be divided into 3 formations:Bachu,Kalashayi and Xiaohaizi.Sedimentary facies of the study area are carbonate platform,which may be further divided into 3 subfacies including evaporated,restricted and open ones.Carbonate rocks are very common,interbedded with clastic and gypsum rocks.During the late Bachu period,terrigenous detrital supplies decreased and a set of carbonate rock rich in biodetritus was formed,and the restricted platform subfacies was deposited.During the early and middle Kalashayi period,the study area was dominated by evaporated and restricted platform subfacies while in the late Kalashayi period,it turned to restricted platform.In the Xiaohaizi period,open platform spread in most of the study area.Due to the cyclicity of sea level change,all microfacies lie in rule and form reservoir-seal assemblages.3 above-mentioned assemblages have been found in Carboniferous,2 in the Xiaohaizi Formation and 1 in the Bachu Formation.Petroleum in the Xiaohaizi Formation mainly locates around well BK4H,M4 and M6.Petroleum in the Bachu Formation mainly locates around well M10,BK4H and M6.
Sequence stratigraphic analysis and subtle trap identification of Silurian around well HT1, Bachu Uplift, Tarim Basin
Zhou Yushuang, Li Qun, Jiang Haijian, He Jinhai, Zhang Yu
2011, 33(4): 359-363. doi: 10.11781/sysydz201104359
Abstract:
Based on sequence stratigraphy and slope-break theories,Silurian stratum around well HT1 in the Bachu Uplift of the Tarim Basin has been divided into 2 3rd-grade sequences (SQ1 and SQ2) and 6 systems according to the analyses of drilling,logging,seismic and core data collected from the study area.Studies of ancient landscape and sedimentary facies have indicated that,from the late Caledonian to the early Hercynian,the Tarim Basin contracted severely and the Hetianhe ancient uplift rose to form northward slope (mainly of tide flat facies).Geologic conditions for the formation of lithologic trap in the study area have been concluded and 4 configuration traps have been identified.
Hydrocarbon migration system and accumulation evolution in Paleozoic, Katake Uplift, Tarim Basin
Li Kun
2011, 33(4): 364-370. doi: 10.11781/sysydz201104364
Abstract(2690) PDF-CN(984)
Abstract:
Rich petroleum resources have been found in Paleozoic of the Katake Uplift,the Tarim Basin.Influenced by multiple stages of tectonic evolution,the study area is characterized by the following complicated accumulation features such as mixed hydrocarbon sources,early oil charging,late gas charging,3 stages of accumulation,and multiple accumulations.The complicated accumulation processes restrict the studies of accumulation principles.Based on studies of the main controlling factors for hydrocarbon accumulations in the region,the hydrocarbon migration system has been divided into 3 big types:fracture,unconformity and reservoir body.4 models for space combination are also discussed.From the aspect of source fracture and region unconformity evolution,the relationship between hydrocarbon migration system evolution and hydrocarbon generation and charging during the 3 key stages for accumulation (late Caledonian-early Hercynian,late Hercynian and Himalayan) are talked about.The regional hydrocarbon source faults such as Tazhong I and II as well as the NE oriented strike-slip faults work as the main pathways for vertical migration.In uplifting and slope regions,T60,T70,and T74 unconformities work together with matrix sandbodies of the Donghetang Formation,providing horizontal pathways for migration.The spatial distribution of karst network and inherited trap controls the favorable direction and accumulation position for hydrocarbon.In the Katake Uplift,the most outstanding feature for accumulation evolution is the cooperation of multiple migration systems composed of fracture,karst and unconformity,resulting in multiple stages of hydrocarbon charging and adjusting in 3 dimensions.
Sand-gathering and reservoir-controlling mechanisms of Paleogene slope-break system in Qikou Sag, Huanghua Depression, Bohai Bay Basin
Zhou Lihong, Pu Xiugang, Zhou Jiansheng, Xiao Dunqing, Chen Changwei, Wang Shuxiang, Hou Zhi, Lin Changmei, Xia Yanyuan
2011, 33(4): 371-377. doi: 10.11781/sysydz201104371
Abstract(3351) PDF-CN(1085)
Abstract:
Based on tectonic background and taking into consideration of sedimentary element,the concept of slope-break system has been proposed.In the Qikou Sag,5 types of slope-break zone have been found in the study area,including tectonic (steep and gentle slopes),flexural,sedimentary,ancient landscape and erosive ones.The distribution of slope-break zone is influenced by ancient tectonic background,fault activity and sedimentary diagenesis.Similar to sedimentary system,various types of slope-break in the Qikou Sag match with each other both horizontally and vertically,accounting for over 70% of the sag area.Slope-break provides underwater channel for source supply,and also offers accommodation,resulting in sand assemblage in slope and depression.Sand distribution is controlled by the following mechanism:source providing sand,groove transporting sand,slope-break controlling sand and source type determining sand gathering.Thanks to wide-distributed reservoir,petroleum has been found all over the sag.The Qibei and Binhai slopes and the Banqiao subsag are the favorable exploration regions for Paleogene lithologic reservoir in the Qikou Sag.
Accumulation mechanism of lithologic reservoir with ultra-low permeability in Chang8 oil formation, Zhenjing Oil Field
Hou Ruiyun, Liu Linwang
2011, 33(4): 378-383. doi: 10.11781/sysydz201104378
Abstract(1809) PDF-CN(985)
Abstract:
The Chang8 oil formation in the Zhenjing Oil Field is characterized by low porosity and ultra-low permeability.Based on the studies of reservoir deposition,diagenesis effect and storage characteristics,the generation mechanism of lithologic reservoir with ultra-low permeability in the Chang8 oil formation has been studied from several aspects such as lithologic trapping condition,accumulation dyna-mics,threshold for fluid charging,time for trapping and petroleum charging as well as controlling factor for sweet point.Conclusions have been made as follows.1) The Chang8 oil formation is favorable for the generation of medium-large lithologic reservoir.2) Sedimentary microfacies is the basic controlling factor for the generation of lithologic reservoir.3) Three elements (fluid charging dynamics,threshold of reservoir physical property,and effective trap matching with hydrocarbon charging period) control the formation of Chang8 lithologic reservoir.4) Prolific reservoir is mainly controlled by reservoir sedimentary facies,and also influenced by natural fracture.
Tectonic features and their relationship with petroleum in Longmen Mountain, western Sichuan Basin
Luo Xiaoquan, Li Shubing, Zhao Xikui
2011, 33(4): 384-387. doi: 10.11781/sysydz201104384
Abstract(3714) PDF-CN(971)
Abstract:
Tectonic deformation of the Longmen Mountain started during Indosinian,and developed during Yanshanian and Himalayan.The beginning time of deformation was later in the south and east than in the north and west.Deformation intensity was stronger in the west than in the east.At the end of late Triassic,due to the closing of the Qinling Ocean,lateral compression took place from north to south,resulting in the uplift of the Micang Mountain and the subduction of the Ganzi-Litang tectonic belt.Scissor compression is the main generation mechanism for the Longmen Mountain.The main tectonic style is nappe,which can be divided into 3 systems.Fault propagation and fault bend folds are favorable for petroleum accumulation.
Distribution and characteristics of carbonate cements in overpressure zone of Junggar Basin
Zhang Liqiang, Luo Xiaorong
2011, 33(4): 388-391. doi: 10.11781/sysydz201104388
Abstract(1861) PDF-CN(1028)
Abstract:
Based on studies of carbonate cement characteristics,the distribution and generation environment of carbonate cements in overpressure zone of the Paleogene Anjihaihe Formation in the southern margin of Junggar Basin have been discussed in this paper by means of thin section observation,well-logging interpretation and O-C isotope analysis.The carbonate cements in the study area are mainly composed of sparry ferri-calcite in connected-crystal form,characterized by low AC,high RT and low GR.Vertically,the cemented layers mainly locate in the pressure-released zone and the overpressure transition zone,including the upper and the lower parts of overpressure top surface,the top of sandstone belt in the overpressure zone as well as the lithologic transition belt in thick overpressure mudstone.Most of the carbonate cements have high negative oxygen isotope values.They were formed before or during petroleum migration under high temperature.
Petroleum migration system in Zhu Ⅲ Depression, Pearl River Mouth Basin, South China Sea
Nie Fengjun, Jiang Meizhu, Li Sitian
2011, 33(4): 392-401. doi: 10.11781/sysydz201104392
Abstract(2158) PDF-CN(1036)
Abstract:
Analyses of seismic profile,gamma ray and acoustic loggings have indicated that petroleum migration system in the Zhu Ⅲ Depression of the Pearl River Mouth Basin is composed of deep fault,unconformity and marine sandstone with high porosity and permeability.The EW oriented structural belt Ⅱ and the southern fault remain active for long time,providing pathways for vertical migration in the WC9-1,WC9-2 and WC19-1 oil-and-gas fields.Tests of inclusion show that temperature decreases from the lower to the upper formation,which may prove vertical migration.Regional unconformities have been found at the bottom of Zhuhai and Zhujiang Formations.Sandstones of TST deposit on the unconformities.Due to favorable porosity and permeability as well as lateral connectivity,the sandstones provide excellent pathways for petroleum migration.According to seismic data,there are 2 obvious NW-SE oriented structural ridges on the T4 and T5 structural planes.Fault,unconformity and sandstone under the ridges form highly effective migration system for the WC13-1 and WC13-2 oilfields in the Wenchang B Sag.
Hydrocarbon generation and expulsion caused by pressure difference between source rock and reservoir during basin subsiding and uplifting
Ma Zhongliang, Zheng Lunju, Qin Jianzhong, Li Zhiming
2011, 33(4): 402-407. doi: 10.11781/sysydz201104402
Abstract(2060) PDF-CN(994)
Abstract:
The evolution history of hydrocarbon-bearing basins can be divided into 3 stages:subsiding (pressure increasing),uplifting (pressure decreasing) and withering (pressure balancing).Through different stages of energy adjustment,the process of hydrocarbon accumulation has been eventually realized.Hydrocarbon generation and expulsion simulations have been carried out with 4 different pressures between source rock and reservoir using formation pore thermocompression simulation instrument.1) During the subsiding stage,hydrocarbon accumulates in sandstones which interbed with source rocks.It is favorable for accumulation in lithologic traps,yet difficult to travel far away.2) During the uplifting stage,the pressure difference between source rock and reservoir promotes the effective discharge and the long-distance migration of hydrocarbon.The bigger the pressure difference is,the higher the discharge effect will be.3 to 6 MPa of pressure difference is the threshold for effective discharge.When uplift and erosion are 300 to 600 m thick,hydrocarbon discharges in large quantity.3) The pressure difference between source rock and reservoir is beneficial for hydrocarbon discharge and source transformation.Hydrocarbon expulsion frequency and power are complementary.If source rock can provide a large quantity of hydrocarbon,the more frequent the hydrocarbon discharges,and the greater the expulsion power is,the higher the hydrocarbon production rate will be.
Accumulation of Upper Cambrian ancient reservoir in Wangcun, southern margin of middle Yangtze region
Li Yanxia, Zhong Ningning, Lin Juanhua, Long Youkang, Li Jinghong
2011, 33(4): 408-413. doi: 10.11781/sysydz201104408
Abstract(1734) PDF-CN(952)
Abstract:
Based on microscopic observation and micro-thermometry measurement of fluid inclusions,combined with basin simulation and crude oil pyrolysis calculation,it is discussed in this paper the Upper Cambrian reservoir in Wangcun,the southern margin of the middle Yangtze region.During the Caledonian period,the southern margin of the middle Yangtze region accepted hydrocarbon from the Lower Cambrian source rocks.In some regions,the Upper Sinian source rocks also worked as effective hydrocarbon kitchens.Wangcun,located on the slope,was the destination of hydrocarbon migration,resulting in primary pool.During the Early and Middle Triassic,primary pools in Sinian and the Middle and Lower Cambrian adjusted due to the Indosinian Movement and the Wangcun ancient reservoir was formed.From the Late Triassic to the Early Jurassic,the Wangcun ancient reservoir was buried deep as the result of flexing or thrust-nappe effect.Crude oils cracked rapidly and oil-cracking-gas source kitchen supplied hydrocarbon in succession.The Wangcun reservoir transformed to gas pool completely,accelerating the dissipation rate of oil and gas.Due to the strong deformations during Yangshan and Himalayan stages,the ancient reservoir finally disappeared.
Oil-source correlation and origin analysis of Mesozoic, North Yellow Sea Basin
Liang Shiyou, He Jiangqi, Ni Chunhua, Li Haihua, Zhou Yushuang
2011, 33(4): 414-418. doi: 10.11781/sysydz201104414
Abstract(2801) PDF-CN(932)
Abstract:
Oil-source correlation and origin analysis have been carried out in Mesozoic of the North Yellow Sea Basin based on tests of 6 samples from 4 wells.Correlations of geochemical parameters such as light hydrocarbon composition,chromatogram and mass spectrum of saturated and aromatic hydrocarbon,and carbon isotope of saturated hydrocarbon have indicated that crude oils in the Lower Cretaceous mainly come from the continental fresh water and Ⅱ2 type source rocks in the Upper Jurassic.The Cretaceous crude oils are similar with the paraffin ones,characterized by naphthene.They are continental mature crude oils with high wax and low sulfur contents,low alum/nickel ratio and good preservation condition.
Source and migrating direction of light oil in Chepaizi Uplift, Junggar Basin
Li Zheng, Zhang Linye, Shen Zhongmin, Guo Chunqing
2011, 33(4): 419-423. doi: 10.11781/sysydz201104419
Abstract(3079) PDF-CN(919)
Abstract:
The discovery of light oil reservoir of Neogene Shawan Formation is a great breakthrough in petroleum exploration history of the Chepaizi Uplift,the Junggar Basin.Studies of geochemical parameters such as stable isotope and biological markers have indicated that the crude oils in the region come from Jurassic hydrocarbon source rocks.Geochemical features of the Dushanzi crude oil are compared with histories of hydrocarbon generation and migration of the Jurassic source rock and tectonic evolution of the Chepaizi Uplift,proving that the light oils mainly come from the Sikeshu Sag and the faulted fold zones of the Northern Tianshan Mountain.The crude oils which sourced from Jurassic migrate vertically through deep fractures into the Neogene Shawan Formation,and then move northward or northwestward along the southern slope of Chepaizi Uplift to the Chepaizi region,and finally accumulate in proper traps.
Comparison of light hydrocarbon between de-absorbed gas and discharged gas in thermal simulation of source rock
Zhang Juhe, Huo Qiuli, Feng Zihui
2011, 33(4): 424-427. doi: 10.11781/sysydz201104424
Abstract(2607) PDF-CN(929)
Abstract:
Correlation between natural gas and source rock can be made since the de-absorbed gas and the discharged gas are similar in certain extent.However,the physically de-absorbed gas or the chemically acid decomposed gas may not correspond with the discharged gas because source rock samples have been taken out of the original environment.Comparative experiments of light hydrocarbon have indicated that,different from the acid decomposed gas,the de-absorbed gas is similar with the discharged gas.As a result,light hydrocarbon parameters of the de-absorbed gas are chosen in gas-rock correlation.
Laboratory studies of differences between oil-derived and kerogen maturation gases
Guo Liguo, Xiao Xianming, Tian Hui
2011, 33(4): 428-436. doi: 10.11781/sysydz201104428
Abstract(2975) PDF-CN(1010)
Abstract:
An immature type-I mudstone collected from the third section of the Tertiary Shahejie Formation (Es33) in the Dongying Sag of the Bohai Bay Basin was studied with laboratory experiments.Products were extracted,fractionated into chemical groups,and re-mixed to obtain synthetic oil (s-oil) with a group composition similar to reservoir oil and a pseudo-kerogen (p-kerogen) composed of 83% kerogen and 17% residual soluble organic matter.The two samples were pyrolyzed in sealed gold tubes under constant pressure and non-isothermal heating conditions and the generated gases were analyzed.The two gases are quite different in their chemical and isotopic composition.Compared with the gas derived from p-kerogen,the s-oil-derived gas is rich in C2-C5 hydrocarbons during the early cracking stages and C1-C3 hydrocarbons are depleted in δ13C throughout the cracking stages.The carbon isotopic ratio differences between the two gases can reach 10‰ (δ13 C1),14‰ (δ13 C2),and 9‰ (δ13 C3).The δ13C2-δ13C3 value of the s-oil gas is much more sensitive to thermal stress than that of the p-kerogen gas and the plots of (δ13C2-δ13C3) versus δ13 C1 and (δ13C2-δ13C3) versus ln(C2/C3) are effective in identifying the two gas types.These results provide a guide to differentiate gases derived from oil cracking from those derived from kerogen maturation.
On-line analysis of oil-bearing fluid inclusions with laser ablation GC-MS
Zhang Zhirong, Zhang Qu, Xi Binbin, Shi Weijun, Rao Dan
2011, 33(4): 437-440. doi: 10.11781/sysydz201104438
Abstract(1633) PDF-CN(965)
Abstract:
In the recently-developed laser ablation GC-MS analysis instrumentation for oil-bearing inclusions,excimer laser of 193 nm wavelength is employed to ablate host minerals (i.e.quartz) so as to release the oil compositions trapped inside.The compositions are cryogenically trapped on line and then analyzed with GC-MS.Geochemical information of crude oil in single fluid inclusion can be obtained with this method.Moreover,similar to traditional methods,various compounds such as gasoline,alkane,iso-alkane,and cyclo-alkane as well as monoaromatics,dicyclic aromatics and polyaromatics can be monitored with this new method.