石油实验地质

2014, 36(1): .

Abstract(279) PDF-CN(481)

Abstract:

Stratigraphic sequences and sedimentary facies of Qigebulak Formation at Xianerbulak, Tarim Basin

Qian Yixiong, Du Yongming, Chen Daizhao, You Donghua, Zhang Juntao, Chen Yue, Liu Zhongbao

2014, 36(1): 1-8. doi: 10.11781/sysydz201401001

Abstract(851) PDF-CN(1148)

Abstract:
Sinian is one of the most important stages of the development of passive continental margin basin in the Tarim Basin. Based on the measurement and analysis of profiles of the Qigebulak Formation (Z₂g) of the upper Sinian at Xianerbulak of Aksu, it has been concluded that the Ⅲ-order sequence boundary surfaces with hiatus and lithofacies transition and the Ⅱ-order surfaces with transgressive onlap and sequence unconformity interface develop at the bottom and on the top of the Qigebulak Formation, respectively. In the middle of the formation, deepening interruption surface and shallowing-upward Ⅳ-Ⅴ sequences develop. The Milankovitch cycle of carbonate rocks has been found, under either peritidal (becoming shallow, fine-grained and thin upwards) or subtidal (becoming shallow, coarse-grained and thick upwards) environments controlled by sea level changes. Stromatolites are widespread, mainly consisting of various microbial mats. The Qigebulak Formation can be divided into 3 lithologic sections from bottom to top, among which the lower section changes from supratidal to intertidal, the lower part of intertidal to intertidal, and intertidal to supratidal; the middle section is characterized by the frequent variation from the lower part of intertidal to subtidal and the stable environment of subtidal. Carbon isotopes are strongly positive at the bottom, stable in the middle and upper sections, and weakly positive at the top. Sea levels change frequently at the bottom, and stably decrease in the middle and upper sections.

Seismic identification and reservoir prediction of reef flat of Upper Ordovician in northern and southern slopes of Katake Uplift, middle Tarim Basin

She Xiaoyu, Dong Zheng, Gong Xiaoxing, Jiao Libo, Tang Tingting, Li Changhong

2014, 36(1): 16-24. doi: 10.11781/sysydz201401016

Abstract(1254) PDF-CN(1001)

Abstract:
When the Lianglitage Formation of the Upper Ordovician deposited, the Katake Uplift in the Tarim Basin was a large-scale isolated platform of carbonate rocks. According to seismic geology as well as drilling and logging data, the seismic and sedimentary facies of the southern and northern slopes were classified as shelf-basin, marginal slope, platform margin, and open platform depositional systems. In the platform margin, the subfacies of reef, bioclastic bank and reef depression were identified. The reef-bank complex was featured by a stacked "tower" structure vertically, and retrograding-aggradational migration horizontally, showing that sea level changes controlled the phased growth of reef flats. Using pattern, palaeogeomorphology and attribute recognition methods, the distribution range of reef-bank complex was further delineated. Prediction results showed that the platform slope edge mainly developed bioclast, calcarenite beach and oolitic beach facies in the west of the northern slope, and the high and steep slope developed reef on the central platform margin; while on the southern slope, platform margin reefs and shoals developed in the northwestern Ka2 block and the southern Ka1 block, showing favorable conditions for the formation of beads-like reef-type oil and gas reservoirs.

Subtle reservoir type and favorable exploration belts in Junggar Basin

Liu Chuanhu

2014, 36(1): 25-32. doi: 10.11781/sysydz201401025

Abstract(1043) PDF-CN(1013)

Abstract:
According to the great potential and complicated accumulation rules of subtle reservoirs in the Junggar Basin, we divided the discovered subtle reservoirs in the study area into 4 types (lithologic, stratigraphic, complex and quasi-continuous ones) and 17 subtypes based on previous exploration experiences. The accumulation characteristics were concluded as followed: the control of multiple sedimentary systems; the occurrence of multiple trap types and the combination of structural-lithologic-stratigraphic traps; multiple hydrocarbon bearing layers; multiple stages of hydrocarbon charging and accumulation; multiple oil and gas plays. The favorable exploration belts of subtle reservoirs include the Shawan Formation in the Chepaizi slope in the western margin of the basin, the Jurassic around the Che-Mo paleo-uplift, the Carboniferous in the Junggar Basin, and the Jurassic tight sandstones in the piedmont depression of the North Tianshan.

Genetic types and distribution characteristics of crude oils from Shahejie Formation in Bonan Subsag, Zhanhua Sag, Jiyang Depression

Song Guoqi, Liu Hua, Jiang Youlu, Gu Guocui, Liu Yali, Lu Hao

2014, 36(1): 33-38. doi: 10.11781/sysydz201401033

Abstract(738) PDF-CN(939)

Abstract:
According to the characteristics of saturated hydrocarbon chromatography, GS/MS and biomarker index, combined with the geochemical features of crude oil, the hydrocarbon genetic types and distribution laws of the Bonan Subsag in the Zhanhua Sag have been analyzed based on the comparison of geochemical features of source rocks from different layers of the Shahejie Formation. The research shows that there are 2 suits of hydrocarbon source rocks in the Bonan Subsag, the 3rd member and the 4th member of the Shahejie Formation. The source rocks in the 4th member of the Shahejie Formation can be further divided into evaporate and sub-evaporate ones. All of the source rocks are obviously different in gammacerane content, Pr/Ph ratio and maturity parameters. Oil source correlation indicates that there are 5 types of oil and they have certain laws in distribution. The crude oils of types Ⅰ and Ⅱ in the 3rd member of the Shahejie Formation both originate from the source rocks in the 3rd member of the Shahejie Formation; however, they are obviously different in maturity and distribution. The crude oils of type Ⅰ in the 3rd member of the Shahejie Formation locate in the middle and upper sections of the 3rd member of the Shahejie Formation in the depression, with relatively lower maturity. The crude oils of type Ⅱ in the 3rd member of the Shahejie Formation locate in deeper formations, with relatively higher maturity. The crude oils of type Ⅰ in the 4th member of the Shahejie Formation distribute sporadically, and originate from the evaporate source rocks in the 4th member of the Shahejie Formation. The crude oils of type Ⅱ in the 4th member of the Shahejie Formation come from the sub-evaporate source rocks in the 4th member of the Shahejie Formation, and are mainly self-generated and self-reserved. Mixed oil and gas come from source rocks in both of the 3rd and 4th members, and locate far away from source center influenced by faults, mainly in step-fault zones.

Characteristics and distribution of reservoirs in Qingdong Sag, Jiyang Depression

Ma Lichi

2014, 36(1): 39-45. doi: 10.11781/sysydz201401039

Abstract(728) PDF-CN(815)

Abstract:
Locating in the Jiyang Depression, the Qingdong Sag, with low exploration degree, is a recent exploration focus. Reservoir characteristics and distribution regularities were studied based on geological, seismic and chemical data. The results showed that, 3 types of crude oils developed in the study area, including salty low-mature, salty mature and normal-mature ones. The salty low-mature and salty mature crude oils both originated from source rocks in the 4th member of the Shahejie Formation, and the normal-mature crude oils originated from source rocks in the 3rd member of the Shahejie Formation. The process of petroleum accumulation was divided into 2 major phases: the first one at the end of Guantao and the second one from Minghuazhen to Quaternary. During the second phase, hydrocarbon charging was widespread, and it was the main phase for accumulation. 4 types of reservoirs generated in the Qingdong Sag, including structural, stratigraphic, lithologic and composite ones. Vertically, oil and gas mainly distributed in the upper section of the 4th member of the Shahejie Formation. On plane chart, oil and gas are abundant in the northeastern strike-slip fault zone, the northwestern slope belt, the central horst belt and the Qingdong-Qingnan transition belt, among which the northwestern slope belt was regarded as the key target for future exploration.

Influence of SE-direction stress produced during thrusting of Keping Uplift on fault sealing of Selibuya Fault in Tarim Basin

Dong Li, Xu Wenming, Zhao Xu, Wang Penghao, Lu Xuemei

2014, 36(1): 46-50. doi: 10.11781/sysydz201401046

Abstract(631) PDF-CN(865)

Abstract:
To evaluate the effect of the Keping Uplift on the Selibuya Fault in the southern margin of the Bachu Uplift during thrusting, and the consequent fault sealing variation, three-dimensional geological modeling and tectonic stress field numerical simulation of the Selibuya Fault have been carried out. Through the data obtained by three-dimensional stress simulation, it has been concluded that, as the result of SE-direction stress of the Keping Uplift, the sliding ratio on the Selibuya Fault plane is variant. The overall sliding ratio is small while that of the middle and southern parts are relatively bigger. The sliding ratio variation is determined by the space geometry of fault. Based on the analysis of the Xianbazha and Yasongdi oil-gas reservoirs which lie in the fault-fold belt flanked the Selibuya Fault, it is thought that the effect of SE-direction stress is limited to the middle and southern parts of the Selibuya Fault. As to the Yasongdi oil-gas reservoir which lies in the middle part of the Selibuya Fault, the SE-direction stress improves the vertical communication and the charge of oil and gas, which is also beneficial to late accumulation.

Fault development characteristics and hydrocarbon accumulation in Pingbei area of Xihu Sag, East China Sea

Yang Caihong, Zeng Guangdong, Li Shangqing, Liang Ruobing

2014, 36(1): 64-69. doi: 10.11781/sysydz201401064

Abstract(790) PDF-CN(1398)

Abstract:
In the Pingbei area of the Xihu Sag in the East China Sea, faults are well-developed, and traps are mainly complex blocks. The generation stage, open/close and combination style of faults directly affect the migration, accumulation and enrichment of oil and gas. The faults in the study area can be classified into 3 types: peak-flourishing, early-flourishing and mid-flourishing. The active period of faults, the lithologic configuration at both sides of the faults and shale smear are the key elements influencing fault sealing. The faults of early-flourishing type in the Pinghu Formation boast the best sealing while those of the peak-flourishing type in the Pinghu-Huagang Formations are relatively worse. There are obvious differences in the degree of hydrocarbon accumulation between various combinations of faults. The combinations of cis-dipping faults show the highest degree of hydrocarbon accumulation; the combinations of anti-dipping faults show the lower degree of hydrocarbon accumulation; the combinations of both cis-dipping and anti-dipping faults show the middle level of hydrocarbon accumulation.

Genetic analysis of high-yield wells of ultra-deep reef-shoal lithologic gas reservoirs：A case study of reef-shoal facies reservoirs in Changxing Formation, Yuanba area, northeastern Sichuan Basin

Fan Xiaojun

2014, 36(1): 70-76. doi: 10.11781/sysydz201401070

Abstract(913) PDF-CN(866)

Abstract:
Since the exploration breakthrough of year 2007, over 1 million m³ of industrial gas flows have been obtained from the Changxing Formation in the Yuanba area, and it is the deepest reef-shoal lithologic gas field in China which mainly develops reef-shoal facies reservoir in platform margin. To further clarify the controlling factors of natural gas enrichment, through the comprehensive research on geology, well logging and geophysics, it is pointed out that the high-quality reservoir development is the major controlling factor and material basis for the high yields of the Changxing Formation in the Yuanba area. Meanwhile, passage system features and the perfect match between structure and favorable reservoir control hydrocarbon accumulation and redistribution. Reef zones in the northwestern Yuanba area are most favorable for hydrocarbon accumulation. The research results have important practical significances for finding potential areas or strata and expanding exploration.

Micro pore and throat characteristics and moveable fluid variation of tight sandstone in 4th member of Xujiahe Formation, Xinchang Gas Field, western Sichuan Basin

Xiao Kaihua, Feng Dongjun, Li Xiupeng

2014, 36(1): 77-82. doi: 10.11781/sysydz201401077

Abstract(820) PDF-CN(826)

Abstract:
In order to evaluate the tight sandstone reservoirs in the 4th member of the Xujiahe Formation in the Xinchang area of the western Sichuan Basin, nuclear magnetic resonance and constant-rate mercury intrusion experiments have been carried out to quantitatively analyze micro pore and throat and moveable fluid variation characteristics. Studies have indicated that the moveable fluid parameters, throat parameters and pore parameters of tight sandstones vary largely. In micro-fractured tight sandstones, pores have an advantage over throats affecting the moveable fluid parameters, and the moveable fluid parameters are mainly controlled by pores. Low moveable fluid content and low producing degree of tight sandstones are mainly caused by the relatively long radius and wide distribution of pores and throats. In micro-fractured tight sandstones, the mercury saturation in throats is higher than that in pores, indicating that the dominant type of reservoir space is pore-fracture type in the 4th member of the Xujiahe Formation, the Xinchang Gas Field.

Accumulation periods of Ordovician reservoirs in Tahe Oil Field

Rao Dan, Qin Jianzhong, Xu Jin, Shi Weijun, Zhang Zhirong, Xi Binbin, Tao Guoliang, Jiang Hong

2014, 36(1): 83-88. doi: 10.11781/sysydz201401083

Abstract(804) PDF-CN(1120)

Abstract:
How many stages of accumulation have the Ordovician reservoirs experienced in the Tahe Oil Field, 2, 3 or even more? The debate causes different understandings of source rock location, hence leads to uncertainty in oil and gas exploration. After years of multidisciplinary joint research, using the most advanced technique of monomer inclusion component analysis, the geochemical features of single oil inclusion during different stages have been identified. The geochemical components of crude oils charged during 2 stages in the southeast of the Tahe Oil Field have been made clear. It has been concluded that the Ordovician reservoirs in the southeast of the Tahe Oil Field have experienced 2 stages of accumulation. The oil inclusions of the 1st stage are featured by yellow-brown fluorescence, higher aromatic component content than saturated hydrocarbon content, complete distribution of n-alkanes (nC₁₁-nC₃₀), and light hydrocarbon missing. They have lower maturity and mainly generate from early migration. The oil inclusions of the 2nd stage are featured by blue-light blue fluorescence, higher saturated hydrocarbon content than aromatic component content, narrow distribution of n-alkanes (nC₈-nC₂₈), and complete light hydrocarbon. They have higher maturity, indicating for late-stage light oil charging. Combined with the simulations of paleopressure and paleotemperature as well as the studies of mixed oil proportion, the charging time and contribution of crude oils of different stages have been discussed, which may guide source rock studies in the Tahe Oil Field.

Molecular characterization of polar species in Canadian oil sand bitumens by electrospray ionization and high resolution mass spectrometry

Liu Peng, Li Maowen, Sun Yongge, Jiang Qigui, Tao Guoliang, Cao Tingting

2014, 36(1): 89-94. doi: 10.11781/sysydz201401089

Abstract(798) PDF-CN(1014)

Abstract:
At present, biodegradation effect on saturated hydrocarbon biomarkers, aromatic biomarker parameters and low molecular weight nitrogen compounds and their parameters is mostly studied, with less attention paid to the research of high molecular weight polar compounds. Four genetically related Canadian oil sand bitumens with various biodegradation levels have been analyzed by negative-ion electrospray ionization (ESI) and Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). The results show that the neutral nitrogen and acidic heteroatom compounds in the oil sand bitumens include N₁,N₁O₁,N₁O₂,N₁S,O₁,O₁S₁,O₂,O₂S₁,O₃ and O₄ heteroatom classes, among which the O₂ class species are most abundant. With increasing biodegradation, the relative abundances of N₁,N₁O₁ and O₁ class species decrease slightly, while the relative abundances of O₂ and O₂S₁ class species increase slightly. The advantage of high resolution mass spectrometry for analyzing high molecular weight polar compounds in crude oil indicates great potential for developing new petroleum geochemistry techniques.

Sedimentary environments and controlling factors of Permian source rocks in northeastern Sichuan Basin：A case study of Muguakou profile in Chengkou

Peng Jinning, Zhang Min, Liu Guangxiang, Pan Wenlei

2014, 36(1): 95-101. doi: 10.11781/sysydz201401095

Abstract(657) PDF-CN(805)

Abstract:
Based on previous analyses as well as filed outcrop observations and sample tests, a case study of the Permian profile in the Chengkou area of the northeastern Sichuan Basin was carried out. Palaeoenvironment was restored according to the parameters of macroelement (oxidizing material) and microelement, and the relationship between palaeoenvironment and source rock development was analyzed. The controlling factors for the vertical and horizontal distributions of source rock were discussed. Several conclusions were made as followed. 1) On plane map, the source rocks of deepwater marine shelf and interplatform basin facies had the highest organic matter abundance and were most widespread in Permian in the study area. The source rocks of innerplatform depression subfacies had lower organic matter abundance. 2) Vertically, the Permian source rocks mainly developed in transgressive hemicycle, and reached the highest organic matter abundance during the maximum flooding period. 3) Organic matter abundance was controlled by ancient biological productivity and organic matter preservation condition. Both of the 2 factors were necessary for high organic matter abundance.

Laboratory experiments of CO₂ flooding in deep-buried high-pressure low-permeability reservoirs：A case study of block Hu96 in Zhongyuan Oilfield

Guo Dianbin, Xu Huaimin

2014, 36(1): 102-105. doi: 10.11781/sysydz201401102

Abstract(714) PDF-CN(744)

Abstract:
Gas and liquid flows coexist in deep-buried high-pressure low-permeability reservoirs after natural depletion. Further studies are demanded due to the complicated characteristics of CO₂ miscible flooding. The environment of deep-buried high-pressure low-permeability reservoir was simulated and the laboratory experiment of CO₂ flooding was carried out using slim tube and long core. It has been concluded that after natural depletion, gas and liquid flows coexist in formation. The minimum miscible pressure (MMP) and the effect of CO₂ flooding decline. But after restoring formation pressure, the effect of CO₂ flooding increases, and achieves the similar result to that by continuous CO₂ injecting under original formation pressure. The conclusion has been applied in CO₂ flooding pilot test of deep-buried high-pressure low-permeability reservoirs in block Hu96 in the Zhongyuan Oilfield, providing technical support for the development of deep-buried high-pressure low-permeability reservoirs.

Application of fuzzy comprehensive evaluation in oil & gas exploration with multidisciplinary assessment & forecasting：A case study on Chaiwopu Sag in Xinjiang

Liu Chunmei, Tan Qing

2014, 36(1): 106-109. doi: 10.11781/sysydz201401106

Abstract(741) PDF-CN(871)

Abstract:
Most of the traditional methods are qualitative assessments in optimized selection of the oil-gas potential exploration targets within one basin or exploration zone by applying the multidisciplinary and multi-index prospecting data and graphics. This paper, makes a case study on the Chaiwopu Sag in Xinjiang, by means of fuzzy comprehensive evaluation, utilizing multidisciplinary resources based on seismotectonics, geochemical exploration, remote sense, radioactive γ energy spectrum, soil micromagnetics, meanwhile, integrating local structure, structure position, hydrocarbon microleakage composite anomalies, oil-gas properties information and other geological essential factors, to carry out quantitative assessment on the multi-target areas, from which some of significant targets are selected as the prospecting prospects.

Probabilistic estimation of reserves and difference between probabilistic and determine methods

Xie Yinfu, Chen Heping, Ma Zhongzhen, Zhou Yubing, Liu Yaming, Wang Renchong, Liu Suyan

2014, 36(1): 117-122. doi: 10.11781/sysydz201401117

Abstract(864) PDF-CN(1560)

Abstract:
In 1997, the Society of Petroleum Engineers (SPE) and the U.S. Securities and Exchange Commission (SEC) recognized the probabilistic estimation of reserves. This method has been accepted by many international oil companies and institutions; however, the determine estimation of reserves is still dominant in China. The probabilistic estimation method was briefly introduced in this article. The difference between the two methods under different uncertainty conditions was compared. The applicability of each method was discussed. Meanwhile, the impact of function form on probabilistic estimation was analyzed. It has been concluded that the probabilistic estimation of reserves takes full account of the conservative, the most likely and the optimistic variety of situations, hence provides a more comprehensive understanding of reserves. The probabilistic estimation is applicable to bigger uncertainties while the determine estimation is applicable to smaller uncertainties. Since the function form of probabilistic estimation parameter may obviously influence estimation result and is subjective, the appropriate function form in strict accordance with relevant standards is demanded to eliminate or weaken the influence.

Characteristics and controlling factors of movable fluid in deep-buried high-pressure and low-permeability sandstone reservoirs：A case study of middle section of 3rd member of Shahejie Formation in Wendong Oil Field, Dongpu Sag

Wang Ruifei, Qi Hongxin, Lü Xinhua, Guo Dianbin

2014, 36(1): 123-128. doi: 10.11781/sysydz201401123

Abstract(731) PDF-CN(1124)

Abstract:
The samples of the deep-buried high-pressure and low-permeability sandstone reservoirs in the middle section of the 3rd member of the Shahejie Formation in the Wendong Oil Field of the Dongpu Sag were tested with nuclear magnetic resonance technique. The characteristics and controlling factors of movable fluid were analyzed with movable fluid percentage and porosity. The results have shown that the T₂ pattern of the samples displays 4 modes, and the T₂ cutoff value is positively correlated with porosity. The movable fluid content is relatively low and the heterogeneity is intense. The higher the permeability is, the wider is the main throat radius. The relation between the movable fluid parameter and the permeability gets better with the increase of permeability. The movable fluid parameter gets higher attenuation velocity with the decrease of permeability and has more sensitivity to the changes of permeability. The micro-pore structure determines the existing state of fluid in deep-buried high-pressure and low-permeability sandstone reservoir. Applying main throat radius, the micro-pore structure controlling movable fluid was token, which has achieved good results. Wide throat controls more movable fluid when physical property is better.

Gao Changlin

2014, 36(1): 999-999.

Abstract(253) PDF-CN(281)

Abstract:

2014 Vol. 36, No. 1

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