2014 Vol. 36, No. 2

Display Method:
2014, 36(2): .
Abstract:
Determinative marks and distribution characteristics of braided river deposits in 1st section of Quantou Formation of Lower Cretaceous in Xiaochengzi area, southern Songliao Basin
Dong Qingshui, Sun Lei, Lou Renxing, Li He, Cui Tong, Dai Dengliang
2014, 36(2): 129-135. doi: 10.11781/sysydz201402129
Abstract(783) PDF-CN(1254)
Abstract:
The Ⅲ-Ⅴ sedimentary sand bodies in the lower part of the 1st section of the Quantou Formation in the southern Songliao Basin were deposited at the beginning of depression sedimentation, and they were important for the Nongan oil reservoirs. Complicated characteristics and unclear origin had delayed the study of reservoir distribution. A case study was carried out in the Xiaochengzi area of the southern Songliao Basin. Through analyzing the multiple perspectives of characteristics about cores, well logging data, seismic interpretation, grain size analysis and so on, the results showed that the Ⅲ-Ⅴ sand bodies in the lower part of the 1st section of the Quantou Formation were proximal and small braided river deposits under special background. 2 sedimentary subfacies (river and flood plain) and 4 sedimentary microfacies were further divided. 6 determinative markers such as rock type combination, rock texture and sand body distribution on profile were concluded for the determination of braided river. According to the relationship between seismic and sedimentary facies, the distribution and variation of braided river deposits in the Ⅲ-Ⅴ sand bodies in the lower part of the 1st section of the Quantou Formation were made clear.
Sequence interface characteristics and spatial and temporal properties of Kongdian Formation of Paleogene in Jiyang Depression
Tan Xianfeng, Jiang Yanxia, Tian Jingchun, Zou Guoliang, Li Hang, Wang Weiqing
2014, 36(2): 136-143. doi: 10.11781/sysydz201402136
Abstract:
Based on seismic, logging, drilling cores and geochemical data, the sequence boundaries of the Kongdian Formation of Paleogene in the Jiyang Depression were systematically studied. On seismic profiles, the boundaries were featured by onlap, downlap, truncation, toplap and concordance. The drilling cores showed weathering crust and lithology-lithofacies transformation characteristics. The rock-electricity relation indicated different types of mutations. The trace elements also showed mutation characteristics. Four sequence boundaries were identified, including the 1st-order sequence interface TSB1, the 2nd-order sequence interface SSB1 and the 3rd-order sequence interfaces SB1 and SB2. As regional unconformity, the sequence interface TSB1 reflected basin transformation. The sequence interface SSB1 was constructed ceremony conversion surface and showed basin rift stage. The sequence interfaces SB1 and SB2 were climate transformation surfaces and showed the cyclic changes in climate factors. The sequence boundaries were significant for the studies of basin formation, climate change and screen fracture activity.
Structural features and controlling on oils in southeastern Beibu Gulf Basin
Xu Zhengyu, Yu Guang, Wu Weiqiang, Ma Qinlin, Huang Ling, Xiong Shaoyun, Cheng Gang
2014, 36(2): 144-152. doi: 10.11781/sysydz201402144
Abstract:
Similar to those of the middle and small basins of continental margin facies in South China, the basement of the Beibu Gulf Basin has experienced 3 evolutionary stages: rift from Paleocene to Eocene, rift to depression transition during Oligocene, and regional subsidence ever since Miocene. Influenced by the basin-forming events such as Shenhu, Zhuqiong, Nanhai and Dongsha, 4 periods of faults developed in the Fushan and Maichen sags in the southeast of the basin, resulting in 3 dominant fault systems of NE,NEE and NW directions, forming 2 tectonic layers. The faults are of flower, piled flower, petal and bush shapes, forming 4 styles including basal tilted strike-slip, basal stretch Domino, cap extensional detachment and cap sliding traction. The Fushan Sag showed an obvious asymmetric stretching process, forming NE-oriented tectonic transfer zone in the middle. The EW-oriented fault system of stage Ⅳ in the southeast of the basin controlled present oil reservoirs in the 2 sags. The nose-like structural zone in the center and the steep slope step zone in the southeast of the Fushan Sag are favorable petroleum exploration targets in the southeast of the basin.
Reservoir characteristics of Silurian in Tahe Oil Field
Wang Xunjie
2014, 36(2): 171-175. doi: 10.11781/sysydz201402171
Abstract:
The Silurian oil and gas reservoir types include stratigraphic, lithologic and compound ones in the Tahe Oil Field. Studies indicate that the Silurian reservoirs have experienced multiple stages of hydrocarbon accumulation and reconstruction, which can be concluded as "multiple stages of hydrocarbon charging, multiple stages of adjustment, late-stage formation".The generation degree of structures and faults controlled the migration and distribution of oil and gas. The active stage of fractures in Silurian matched with hydrocarbon charging stage, and the generation degree of fractures controlled the migration and accumulation of oil and gas in Silurian. The favorable reservoirs of channel mouth bar and tidal channel facies determined the enrichment of oil and gas. The traps adjacent to the Silurian erosional pinch-out line are the gathering places of normal oil. The southern Tahe Oil Field is favorable for tectono-stratigraphic reservoir exploration. The Tuoputai area of the Tahe Oil Field is favorable for primary pool exploration.
Reservoir characteristics and diagenesis of Devonian Donghetang Formation in Bachu-Maigaiti area
Zhang Yongdong, Shao Zhibing, Qiao Guilin, Han Yu
2014, 36(2): 176-181. doi: 10.11781/sysydz201402176
Abstract:
According to the analyses of rock slice, cast slice, SEM and well logging data, the sedimentary, petrologic characteristics and diagenesis of the upper and the lower sandstone segments of the Donghetang Formation in the Bachu-Maigaiti area were studied. Deposited in littoral environment, the Donghetang Formation was featured by higher compositional maturity and textural maturity, and both of the 2 maturities were higher in the upper sandstone segment than in the lower one. Dissolution pores served as the main reservoir space, and their distribution was determined by grain size and intergranular material. For example, the dissolution pores were well developed in the sandstone segment with bigger grain size and calcareous cementation. The most important diagenesis effects included compaction, cementation, cement dissolution, quartz alkali dissolution, metasomasis, recrystallization and structure cataclasis. According to the division standard of diagenetic phase, the Donghetang Formation was in the B stage of middle phase.
Source-to-sink system during Yageliemu period of Early Cretaceous in Tahe and southern Tianshan areas
Su Juan, Kang Rendong, Xing Fengcun, Liu Xiaofeng
2014, 36(2): 182-187. doi: 10.11781/sysydz201402182
Abstract:
Based on drilling, seismic and outcrop data, the source-to-sink system and the configuration of sedimentary systems in the Tahe and southern Tianshan areas during the Yageliemu period of the Early Cretaceous were studied. Bounded with the Yakela fault arch and characterized by significant north and south zonality in landform structure, the Cretaceous was thin on the top and thick on the flanks, and was partially missing on the top of the uplift. The source-to-sink system was obviously controlled by landform, developing 3 source areas (northern, southern and eastern) and 2 sink centers (Tahe and Kuqa). Surrounding the Tahe sink center, the fan delta group with the Yakela fault arch short source developed, and the braided delta group with the Yaken, Yuqi, Jilake, Akeyasu and Tuoputai sources developed. The Yakela fault arch played a significant role in sedimentary system distribution.
Evaluation of accumulation system for shale gas of Doushantuo Formation in western Xuefeng Mountain
Li Xubing, Chen Miankun, Liu An, Wei Kai, Wang Baozhong
2014, 36(2): 188-193. doi: 10.11781/sysydz201402188
Abstract:
Shale gas is an unconventional resource with great exploration potential and continuous accumulation. At present, our country has not carried out large-scale shale gas resource evaluation. The accumulation factors such as TOC, organic matter type, maturity, crack, porosity, permeability, brittle mineral content, thickness and depth of shale, and hydrocarbon potentials are analyzed in this paper. Based on the study of stratigraphic correlation and paleogeographic characteristics of the Doushantuo Formation, and the key parameters for shale gas sweet spots, the results suggest that the Sangzhi-Shimen synclinorium and the Yidu Hefeng anticline zone are the most favorable areas for shale gas exploration which will become strategic breakthrough areas in the western Xuefeng Mountain.
Controls of synsedimentary faults on sedimentary filling of 1st member of Liushagang Formation in Yongan-Bailian areas in Fushan Sag, Beibuwan Basin
Wang Miao, Huang Chuanyan, Zuo Zongxin, Lin Zhengliang, Wang Baohua
2014, 36(2): 194-199. doi: 10.11781/sysydz201402194
Abstract(1059) PDF-CN(714)
Abstract:
The comprehensive analyses of the sedimentary systems and synsedimentary faults in the 1st member of the Liushagang Formation in the Fushan Sag were made based on high-resolution sequence stratigraphy, sedimentology and structural geology. 3 sedimentary systems were concluded including braided river delta, fan delta and lacustrine sedimentary system. 9 sedimentary microfacies were classified. The synsedimentary systems in the 1st member of the Liushagang Formation in the Yongan-Bailian areas of the Fushan Sag were divided into the western extending accommodation fault system, the eastern strike-slip accommodation fault system and the central transfer fault system. The differential activities of the faults on each side of the central transfer fault system resulted in the migration of formation thickness center, migrating from west to east in the 1st member of the Liusha-gang Formation. The space-time evolution regularities of sedimentary systems indicated that the main delta sand body also migrated from west to east in the 1st member of the Liushagang Formation. The development of synsedimentary faults controlled the distribution of sedimentary systems and 3 controlling patterns were concluded.
Petroleum distribution rules and controlling factor analysis of Gulf of Mexico Basin
Liu Yanli, Xu Xianghua
2014, 36(2): 200-205. doi: 10.11781/sysydz201402200
Abstract(1232) PDF-CN(1020)
Abstract:
The Gulf of Mexico Basin is a composite basin with passive continental margins superimposing on rift basin. The basin has experienced 3 evolution stages. Based on the research of basin formation and evolution, the distribution rules of oil and gas were analyzed. Oil and gas mainly developed during the passive margin period. There are 5 sets of oil and gas plays including the conventional and unconventional petroleum. The 3 main conventional oil and gas plays are located following seaward direction, which include the Jurassic-Cretaceous play, the Paleogene play and the Neogene play, from onshore to offshore. The main controlling factors are progradation, salt and sand distribution. The 2 unconventional oil and gas plays include the Eagle ford and the Haynesvill-bossier shale belt, both locating onshore. The main controlling factors are organic matter abundance and thermal evolution.
Quantitative characteristics of biomarkers of crude oils of Tahe Oil Field
Zhang Qu, Song Xiaoying, Zhang Zhirong, Tenger
2014, 36(2): 206-210. doi: 10.11781/sysydz201402206
Abstract(1013) PDF-CN(676)
Abstract:
22 crude oils of the Tahe Oil Field have been quantitatively analyzed with gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) for saturate and aromatic biomarkers. The contents of dibenzothiophene (DBT) and pristane (Pr) of middle-south and east area oils are relatively higher than those of middle-north area, which indicates that the former has a depositional environment of carbonite and stronger reducing environment than the latter. The content of C35 homohopanes is higher in the oils of middle-north area than those of south-east, indicating for delamination water body of the former and stronger reducing environment. The content of C29S steranes increases with that of DBT and methyl phenanthrenes and maturity degree. The high contents of 25-norhophane and bisnorhopane in middle-north area reveal the experience of biodegradation.
Fluid inclusion characteristics of reservoirs in Kelasu tectonic zone of Kuqa Depression and its accumulation information
Feng Songbao, Xu Wenming, Dun Yapeng
2014, 36(2): 211-217. doi: 10.11781/sysydz201402211
Abstract:
The analyses of fluid inclusion characteristics of reservoirs in the Kelasu tectonic zone of the Kuqa Depression show that saline inclusions are abundant while a few of gaseous hydrocarbon inclusions and gaseous-liquid inclusions also exist. The inclusions mainly locate in quartz as lines or in planar distribution. They are small, usually about 4-10 μm. The homogenization temperature of saline inclusions is 86.2-196.1 ℃, usually in continuous distribution and varies between different regions. The salinity of saline inclusions is low, generally 2%-4%. The hydrocarbon inclusions have low abundance, usually 0.1%-8.1%. It has been concluded that natural gas charged rapidly and continuously in the Kelasu tectonic zone, and the late charging had stronger strength. Burial history studies show that natural gas accumulations have occurred ever since the Kuqa period, and are later in the Keshen zone than in the Kela zone. From east to west, accumulation period becomes later and later.
Origin and significance of Sinian original and coexist bitumen of central Sichuan Basin
Liu Dan, Li Jian, Xie Zengye, Guo Jianying, Hao Aisheng
2014, 36(2): 218-223. doi: 10.11781/sysydz201402218
Abstract:
The previous studies indicated that the widespread bitumen of the Sinian Dengying Formation in the central Sichuan Basin were epigenetic reservoir bitumen, which originated from the cracking of oil to gas in paleo oil pools and sourced from the Lower Cambrian mudstones. However, the original coexisting bitumen were also found in the Sinian Dengying Formation in the central Sichuan Basin, which could not be explained by the above opinion. Through the restudy of bitumen occurrence under microscope, biomarker characteristics and bitumen content, combined with the analysis of carbonate inorganic microelement, it was concluded that some of the bitumen came from the carbonate source rocks in the Dengying Formation, and the carbonate rocks in the Dengying Formation were qualified for favorable source rocks in paleo sedimentary environment and preservation condition.
Lowest limit of organic carbon content in effective source rocks from Lucaogou Formation in Jimusar Sag
Kuang Lichun, Gao Gang, Xiang Baoli, Wang Xulong, Wang Chengyun, Liu Guangdi
2014, 36(2): 224-229. doi: 10.11781/sysydz201402224
Abstract(1017) PDF-CN(809)
Abstract:
The generation and organic geochemical features of source rocks from the Lucaogou Formation in Ji174 well area in the Jimusar Sag of the Junggar Basin were studied. According to hydrocarbon expulsion laws as well as the relationships between soluble organic matter transformation rate, pyrolysis S1/w(TOC) and organic carbon content, the lowest limit of organic carbon content for hydrocarbon expulsion in lutaceous source rocks was determined. In the Lucaogou Formation in Ji174 well area, lutaceous source rocks developed well, and their hydrocarbon generation conditions were similar even though the lithology was various. Due to the differences in mineral compositions and organic matter characteristics, the lowest limit of organic carbon content for hydrocarbon expulsion was different. For pure lutaceous, silty, calcareous and dolomite source rocks, the lowest limits were 2.50%,2.80%,1.45% and 1.30%, respectively. The carbonate-containing effective source rocks took larger proportions than pure and silty mudstones, all over 50%. It was concluded that in the Lucaogou Formation in Ji174 well area, lutaceous effective source rocks were well-developed, and the lowest limits of organic carbon content were higher, which were favorable for hydrocarbon reservoirs.