2010 Vol. 32, No. 6

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2010, 32(6)
Abstract(1643) PDF-CN(715)
Abstract:
2010, 32(6): 518-518. doi: 10.11781/sysydz201006518
Abstract:
HYDROCARBON EXPLORATION PROSPECTS IN THE EAST SECTION OF THE MAIGAITI SLOPE IN THE TARIM BASIN
Lv Xiuxiang, Yang Haijun, Bai Zhongkai, Lei Ganglin, Liu D, an
2010, 32(6): 521-526. doi: 10.11781/sysydz201006521
Abstract(4437) PDF-CN(960)
Abstract:
It was considered that the east section of Maigaiti Slope in the Tarim Basin had the favorable conditions for hydrocarbon accumulation. Cambro-Ordovician hydrocarbon source rocks and a set of carboniferous oil source rocks with high abundance which develop in this area provide material foundations for the formation of large oil/gas fields in this area. There are several reservoir-seal assemblages in the Maigaiti Slope. One is the assemblage of Ordovician weathered crust of the buried hill as reservoir bed, and Silurian mudstone and Carboniferous lower mudstone member as seals. The other is the assemblage of the Carboniferous glutenite member and bioclast limestone member as reservoir bed, and low mudstone member and medium mudstone member as seals. Reservoir beds with favorable reservoir condition are distributed stably, and seals are in perfect condition. Favorable reservoir-seal asseinblages provide favorable foundation for hydrocarbon enrichment. Maigaiti Slope experienced development processes of north dipping slope during Cambro-Ordovician and south dipping slope since Carboniferous period, and is located at pivot part of the tectonic movement, which is favorable for the hydrocarbon accumulation and the later storage. It is a favorable area for the hydrocarbon accumulation and reservoir with favorable hydrocarbon prospects. It is predicted that Ordovician buried hill and Carboniferous anticline reservoir in the east section of Maigaiti Slope should be the main objects for the further exploration.
ANALYSIS OF PALEOZOIC RESERVOIR PRESERVATION IN THE NORTH CHINA
Yang Fan, Zhou Xiaojin, Ni Chunhua, Liu Yunli
2010, 32(6): 527-531. doi: 10.11781/sysydz201006527
Abstract(3417) PDF-CN(730)
Abstract:
This paper mainly studied the regional controlling effect of Meso-Cenozoic tectonic evolution to the Paleozoic reservoir preservation in the North China. Beside the analysis of the condition of Paleozoic seal rocks, this paper mainly analyzed conditions of overlying direct cap rocks, regional cap rocks and the overall sealing composed by Meso-Cenozoic basins superposition. The results show that the hydrocarbon preservation was better in the west than in the east, better in Lower Paleozoic than in the Upper Paleozoic, and better in the northen part of North China than in the souther part of North China. Benxi Formation and Shihezi Formation are the main regional cap rocks in the Paleozoic. The eastern Paleogene and the western Triassic formations provided regional cap rocks for the Paleozoic hydrocarbon preservation. The sealing condition is an important factor which caused the hydrocarbon preservation difference between the east and the west. The Central Ordos Basin and the eastern deep fault depression to inside slope in the North China are favorable units for the hydrocarbon preservation.
DISCUSSION OF VOLCANIC FACIES DIVISION IN STUDIES OF BASIN PETROLEUM RESERVOIR
Zhang Yuming, Lu Jianlin, Li Ruilei, Zhang Xi
2010, 32(6): 532-535. doi: 10.11781/sysydz201006532
Abstract(3210) PDF-CN(826)
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Volcanic reservoir lithofacies division is very important to determine favorable reservoir distribution and reservoir prediction. Aiming at volcanic rock reservoir exploration needs, combined with petroleum geological characteristics of volcanic in the Changling Fault Depression of the Songliao Basin, subfacies and microfacies of volcanic eruption and overflow facies were classified. The subfacies were divided into near crater, volcanic slope and far away from crater ones. The microfacies were divided into upper, middle and lower ones. New volcanic reservoir lithofacies division method reflects the characteristics of volcanic rock reservoir generation and distribution. It makes prediction effectively and is favorable for volcanic rock reservoir exploration.
PRESSURE DISTRIBUTION AND GENESIS OF FLUID IN THE UPPER PALEOZOIC OF THE ORDOS BASIN
Wang Shengli, Xu Huazheng
2010, 32(6): 536-540. doi: 10.11781/sysydz201006536
Abstract(3067) PDF-CN(858)
Abstract:
The fluid pressure in the Upper Paleozoic of the Ordos Basin reflects the type of gas reservoir from one aspect. The deep gas reservoir has the negative abnormal pressure, and with rises of the buried depth and Ro value of coal layer, the negative abnormal pressure would rise correspondingly. The gas reservoir in connection with the structure shows hydrostatic pressure or positive abnormal high pressure. The negative abnormal pressure is related to the regional structure uplift denudation and the pressure is controlled by evolution degree of maturation. The high gas generation of the coal layer and high vaporization in high evolution zone caused the low nature gas moisture, low gravity and low pressure coefficient in the center of the basin. With the lower thermal evolution at the basin magin, the nature gas moisture, gravity and pressure coefficient will be higher. The regular variation of pressure coefficient in the deep gas accumulation reflects the short distance gas migration and in-situ gas reservoir formation.
COMPARISON ANALYSIS OF MESO-CENOZOIC HYDROCARBON GENERATION BETWEEN THE NORTH JIANGSU BASIN AND THE SOUTH YELLOW SEA BASIN
Liu Yurui
2010, 32(6): 541-546. doi: 10.11781/sysydz201006541
Abstract(3184) PDF-CN(917)
Abstract:
The North Jiangsu Basin and the South Yellow Sea Basin are a unified Mesozoic-Cenozoic basin.The North Jiangsu Basin has seen fruitful exploration. Four out of seven sets of dark mudstone only contribute to hydrocarbon accumulation by geochemical analysis, in which three are wide lacustrine lime mudstones in depression which is characterized with wide distribution, high quality and significant in lithology-electricity, the other one is pure mudstone in rift lake. It can conclude that there are 5 sets of source rocks in the Southern Depression which are more in numbers and slightly larger in thickness than in the North Jiangsu Basin, and only one in the Northern Depression of the South Yellow Sea Basin. The source rocks of the South Yellow Sea Basin are similar in original environment and lithology-electricity with the North Jiangsu Basin, but less in quality and continuity. Source rocks develop at the low mature-mature stage in two basins, of which the South Yellow Sea Basin is lower in maturity than the North Jiangsu Basin resulting to narrow distribution of expulsive petroleum source rock. Quality, maturity and degree of expulsion of source rocks dominate abundance of hydrocarbon resources in sags of the North Jiangsu Basin, higher maturity and hydrocarbon expulsion of source rock, higher abundance of resources, otherwise it is low. Deeper sediments are buried in rift sag, more mature in source rocks. The end of the Sanduo stage is time for complete maturity of source rocks. In general, the South Yellow Sea Basin is not larger than the North Jiangsu Basin in resource potential where the Southern Depression is better than the Northern Depression.
THE RESERVOIR CHARACTERISTIC OF DEEPLY-BURIED SANDSTONE IN THE CENTER OF JUNGGAR BASIN
Wang Furong, He Sheng, He Zhiliang, Zhang Fushun
2010, 32(6): 547-552. doi: 10.11781/sysydz201006547
Abstract(3592) PDF-CN(827)
Abstract:
Many discovered petroleum mainly develop in the deeply-buried Jurassic and Cretaceous sandstone reservoirs in the center of Junggar Basin and intergranular secondary porosity develop at the depth of 3 500~6 200 m belong to a stage of late diagenesis. The porosity is about 4%~20% resulting from organic acid that generates from hydrocarbon maturation dissolving carbonate cements and silicate. According to the relationship among temperature, depth and Ro (vitrinite reflectance), there exists the other small scale secondary porosity band vertically resulting from organic acid dissolving ferro carbonate cements at the depth of 6 500 m.
GEOCHEMICAL TECHNOLOGY FOR STUDY OF HYDROCARBON FORMATION AND ACCUMULATION IN MARINE SEQUENCES:RECENT ADVANCES
Liu Wenhui, Qin Jianzhong, Tenger, Rao Dan, Zhang Meizhen
2010, 32(6): 553-559. doi: 10.11781/sysydz201006553
Abstract(2132) PDF-CN(967)
Abstract:
There are special characteristics in evolution of petroleum system of marine sequences in Chinese complicated superimposited basins under condition of multiple stages of tectonic activity. The development of experimental technology of petroleum geology and geochemistry is playing more and more important roles in construction of basic theory of hydrocarbon accumulation of the superimposited basins and in understand of geologic and geochemical process for petroleum exploration and production. A series of experimental technologies which were suitable for the special and complex superimposited basins were developed in recent years. The most important ones among them included assessment of hydrocarbon generation of source rocks, tracing of hydrocarbon migration and analysis of hydrocarbon accumulation. All of them are very helpful for understanding of hydrocarbon accumulation mechanism and distribution in the superimposited basins.
PARTITION AND CONTRAST ON GENETIC TYPE OF CONTINENTAL NATURAL GAS IN THE SICHUAN BASIN
Shen Zhongmin, Jiang Min, Liu Sibing, Zhu Hongquan, Gong Yajun
2010, 32(6): 560-565. doi: 10.11781/sysydz201006560
Abstract(3602) PDF-CN(872)
Abstract:
The paper studies systematically the light hydrocarbon fingerprint, carbon isotope, hydrogen isotope and noble gas isotope of natural gas in the Sichuan Basin. The natural gas carbon isotope C1-C2 relationship from different areas and formations show that the natural gas in the Sichuan Basin were affected by parent types of sources rock, maturity, migration and other factors. The light hydrocarbon fingerprint indicates the major source of natural gas in the Western Sichuan Depression is humus-type, the sources in southern Sichuan Basin, eastern Sichuan Basin and the central region of Sichuan Basin are both humus-type and sapropel type, and the natural gas are mainly oil-type gas. The C1 isotope of natural gas from T3x2 in the middle area of the Western Sichuan Depression are higher than other areas and C2 isotope are less than -28‰, which shows oil-type gas and higher maturity feature. The natural gases of other formations in study area are concentrating distribution relatively and display the typical feature of coal-related gas. The marine and continental natural gas in the Sichuan Basin could be distinguished by carbon isotope δ13C2=-28‰ and hydrogen isotope δD1=-140‰ of the natural gas. The noble gas isotope shows that the natural gas are shell source without the addition of mantle noble gases.
EVALUATION ON DALONG FORMATION SOURCE ROCK IN THE NORTH SICHUAN BASIN
Fu Xiaodon, Qin Jianzhong, Tenger, Wang xiaofang
2010, 32(6): 566-571. doi: 10.11781/sysydz201006566
Abstract(3572) PDF-CN(962)
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The argillaceous and siliceous rocks in the Dalong Formation of Upper Permian in the north Sichuan Basin are excellent marine source rocks with high organic matter abundance and good organic matter type. The maturity of Dalong Formation changes greatly,which reach over-mature stage in Well Heba1 section while still in low-middle mature satge in Guangyuan and Wanyan areas localed in edge of the basin. The hydrocarbon-generation intensity of Dalong Formation source rocks is mainly lower than 20×108 m3/km2. There is a good time-space matching relationship between the source rock in Dalong Formation and the excellent reef and shoal facies reservoirs in Changxing-Feixianuan Formations,which result in the oil and gas origined form Dalong Formation accumulated in the excellent reservior more efficiently and make great contribution to the large and medium-sized gas fields such as Puguang. Related to the marine source rocks in other geological periods, main hydrocarbon-generation periods of Dalong Formation source rocks is later and that is beneficial to the preservation of gas reservoir. Is there any residual oil pool in Guangyuan and Wanyuan areas where Dalong Formation is still in low-middle maturity, which is worth of particular attention.
CHARACTERISTICS AND HYDROCARBON GENERATION EVOLUTION OF PINGLIANG FORMATION SOURCE ROCKS, SOUTHERN ORDOS BASIN
Ni Chunhua, Zhou Xiaojin, Wang Guoshou, Yang Fan, Liu Yunli
2010, 32(6): 572-577. doi: 10.11781/sysydz201006572
Abstract(3188) PDF-CN(914)
Abstract:
Combining organic geochemistry together with organic petrology, the source rocks of the Pingliang Formation of the Middle Ordovician in the southern Ordos Basin have been systematically studied in this paper. Controlled by sedimentary facies, the thickness of hydrocarbon source rocks of the Pingliang Formation was characterized by horizontal distribution of thick in the south but thin in the north. The abundance of organic matter was characterized by longitudinal distribution of high in the below but low in the upper area. The types of organic matter were identified by type index of carbon isotope and the result reflected that there was mainly sapropelic kerogen. The marine vitrinite reflectance showed that maturity was higher in the east than in the west and it was mainly during the late-mature and the high-mature stage. The hydrocarbon source rocks of the Pingliang Formation worked as effective source rocks. Using the PetroMod software, combined with the hydrocarbon generation simulation experiments, it had been concluded that, source rocks of the Pingliang Formation began to generate oil in the Late Triassic, reached oil generation peak in the Middle Jurassic and generated gas in large scale in the Early Cretaceous. The muddy hydrocarbon source rocks of the Pingliang Formation have some natural gas potential in the southern Ordos Basin.
STUDY ON SECONDARY MIGRATION MECHANISM OF NATURAL GAS
Jiang Lin, Bao Dongmei, Liu Shaobo, Hong Feng, Zheng Yongping, Cai Bing
2010, 32(6): 578-582. doi: 10.11781/sysydz201006578
Abstract(2037) PDF-CN(812)
Abstract:
Natural gas is composed of some kind of low molecular hydrocarbon, but the accumulated natural gas in reservoir is mainly composed of methane generally. This paper studied the secondary migration characteristics of natural gas by the physical simulation experiment, and discovered that the secondary migration of natural gas is a kind of Intermittent Flow which developed from the alternation of Plug Flow and Preferential Flow.The Intermittent Flow of natural gas can cause heavier hydrocarbon captured and sealed off into rock pores with formation water. And then this paper discussed composition alternation mechanism of natural gas during secondary migration based on the analysis of hydrocarbon formation and the relationship of gas, water and rock. It is resulted that the composition differentiation in the secondary migration of natural gas, heavier hydrocarbons captured and sealed off into rock pores caused the Intermittent Flow of natural gas and the dissolution of oil preserved in the secondary migration path are main reasons why the accumulated natural gas is composed of much more methane.
GEOLOGICAL STUDY AND PHYSICAL SIMULATION EXPERIMENT ON THE LIMITATION OF FAULT-SEALING
Li Hongyi, Jiang Zhenxue, Dong Yuexia, Wang Xudong, Li Xiaoying, Qi Lixin
2010, 32(6): 583-587. doi: 10.11781/sysydz201006583
Abstract(3577) PDF-CN(957)
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The paper discussed the geological forming cause of reservoirs which distribute like brushes, brought forward the limitation of fault-sealing, and validated it by physical simulation experiment. Through the comparison between measured data and calculated data of oil column height sealed by fault, it is believed that the fault-sealing for oil and gas is limited. When hydrocarbon column height reaches the threshold, oil will spill from the top of reservoir along fault, and the scale of reservoir will remain invariable. When the sealing capacity of fault is settled, the area of oil and gas in fault-screened traps is controlled by the obliquity of reservoirs. The area of oil and gas increases with the decrease of reservoirs obliquity.
SIMULATION OF INFLUENTIAL FACTORS OF DISPERSIVE RESOLUBLE ORGANIC MATERIALS RESIDENT IN SOURCE ROCKS
Li Yongxin, Wang Hongjun, Wang Zhaoyun
2010, 32(6): 588-591. doi: 10.11781/sysydz201006588
Abstract(2243) PDF-CN(1042)
Abstract:
The simulations of marine marl with low organic matter abundance under different fluid pressures were carried out. The results indicated that, the peak time of hydrocarbon generation and expulsion was around 310℃ under the pressure of 10 MPa, with the expulsive oil rate and the total oil yielding rate of 182.5 and 193.4 mg/g, respectively. Under 20 MPa, the temperature corresponding to the hydrocarbon generation and expulsion peak was about 330℃, with the expulsive oil rate and the total oil yielding rate of 92.4 and 111.4 mg/g, respectively. It has been suggested that, the increase of pressure represses the thermal evolution of organic materials. It enlarges the effective hydrocarbon expulsion stage of source rocks in addition to postponing the major expulsion period. As a result, the residence time of resoluble organic materials with large quantity has been enlarged, which provides material basis for the generation of gas during the high evolutionary phase.
EXPERIMENTAL STUDY OF PROPERTIES AND INFLUENCING FACTORS OF GAS FLOW IN TIGHT CORE
Wen Xiaohong, Zhou Tuo, Hu Yong, Zhu Huayin, Wang Shuying
2010, 32(6): 592-595. doi: 10.11781/sysydz201006592
Abstract(2134) PDF-CN(855)
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Properties of gas flow in tight gas reservoirs are different from those in conventional gas reservoirs due to complex pore structure and tiny pore throat. Gas drive experiment by increasing pressure progressively and constant depletion physical simulation experiment were used in this paper so as to analyze gas flow characteristics in sandstone reservoir cores. The results indicated that, flow pressure difference enough big was required to overcome friction. This is the threshold for tight gas reservoir development. Gas flow properties are influenced by many factors such as basis permeability, water saturation, core length and overburden pressure. They may influence gas well productivity and rate maintenance capability and should be paid attention to before tight gas reservoir development.
RESEARCH OF "LABYRINTH-STYLE" HYDROCARBON MIGRATION AND ACCUMULATION SIMULATION BASED ON THE CORNER POINT GRID MODEL
Liu Zhifeng, Wei Zhenhua, Wu Chonglong, Tian Yiping, Mao Xiaoping
2010, 32(6): 596-599. doi: 10.11781/sysydz201006596
Abstract(2286) PDF-CN(818)
Abstract:
Considering the actuality of hydrocarbon migration and accumulation simulation (HMAS), the paper established 3D geological model of the petroleum basin based on the Corner Point Grid Model (CPGM). On the basis of studying the migration and accumulation conditions of the oil and gas to be in equilibrium in different geology environment, using HMAS parameter calculation method of the predecessors and adopting the combination mode of Darcy's law and artificial intelligence algorithms to calculate the hydrocarbon migration velocity, the author proposed the "Labyrinth-Style" HMAS idea and programmed the independently running module. This module has been tested in the actual exploratory area—the Dongying Sag in Bohai Bay Basin, the maturing exploratory area of Shandong Province. The satisfactory results have been obtained. The research achievement provides a good analysis tool for decreasing the risk of the petroleum exploration.
THE MECHANICAL ANALYSIS AND EXPERIMENTAL RESEARCH OF SECONDARY HYDROCARBON MIGRATION
Yang Lei, Qi Yaoguang, Sun Zhixin, Ren Xuhu, Liu Xinfu
2010, 32(6): 600-604. doi: 10.11781/sysydz201006600
Abstract(2166) PDF-CN(823)
Abstract:
Characteristics of the clastic rock reservoir porosity and permeability have important influence to the secondary hydrocarbon migration and accumulation. Different layers of the reservoir rocks have different pore structure and accumulation resistance, and oil and gas reservoirs in different structural positions have different reservoir forming dynamics. The reservoir forming dynamic, together with the reservoir porosity and permeability characteristics determine the oil and gas migration, accumulation and the process of reservoir formation. In this paper, the authers analyed and calculated dynamic and resistance of the secondary hydrocarbon migration and accumulation, then carried out a systematic physical simulation experiment on the focus of the buoyancy as a driving force of the oil and gas migration, and analyzed different controlling factors of the secondary hydrocarbon migration. The works of this paper laid the foundation for carrying out physical simulation of the structural deformation and hydrocarbon migration, and also was the experimental reference for the reservoir formation analysis and evaluation.
THERMAL EVOLUTION AND HYDROCARBON GENERATION IN THE CAOHU SAG OF THE TARIM BASIN-BASED ON IES BASIN SIMULATION TECHNOLOGY
Wang Bin, Zhao Yongqiang, Luo Yu, Ma Hongqiang
2010, 32(6): 605-609. doi: 10.11781/sysydz201006605
Abstract(2938) PDF-CN(1093)
Abstract:
On the basis of single well burial history simulation in the Caohu Sag of the Tarim Basin, studies of thermal evolution and hydrocarbon generation histories have been carried out with the IES-PetroMod basin modeling software. Several conclusions were made. a) In the sag, Ro of the Cambrian and the Ordovician source rocks had reached 0.5% during the middle Ordovician and had begun to generate hydrocarbon. The peak stage of hydrocarbon generation was from the middle Caledonian to the early Hercynian. The Cambrian source rocks had entered the over mature stage during the early Hercynian. The Ordovician source rocks had entered the highly mature gas generation stage in the early Hercynian and had reached the over mature stage in the late Hercynian. b) In the east and the west edge of the sag, the Cambrian source rocks reached the oil generation peak in the middle Caledonian and the late Hercynian. The Ordovician source rocks reached the oil generation peak in the Hercynian and the Indosinian. c) In the Kuerle uplift, the Cambrian and the Ordovician source rocks had entered the mature and the highly mature stages in the early Hercynian. During the late Hercynian, hydrocarbon generation stopped and the early hydrocarbon was destroyed. From the late Hercynian to the Himalayan, the Kuerle structural nose continued subsiding, but the burial depth was limited and there was nearly no probability for secondary hydrocarbon generation.
SIMULATION EXPERIMENTS ON THE TSR SYSTEM OF DIESEL AND MAGNESIUM SULFATE
Yue Changtao, Li Shuyuan, Xu Ming, Zhang Yonghan, Zhong Ningning
2010, 32(6): 610-614. doi: 10.11781/sysydz201006610
Abstract(2544) PDF-CN(774)
Abstract:
Thermal simulation experiments on the system of diesel and magnesium sulfate were carried out using an autoclave operated at high temperature and high pressure in the presence of water. Properties of the gas-oil-solid 3-phase products were analyzed by some advanced analytical methods including gas chromatography, microcoulometry, capillary gas chromatography combined with a pulsed flame photometric detector (GC-PFPD), FT-IR and X-ray diffraction. The results show that the reaction can proceed at 450~550℃ to produce MgO, S, C, H2S, CO2, and a series of organic sulfur compounds such as mercaptans, sulfoethers and thiophenes as the main products. The reaction kinetics was also studied and the activation energy of the reaction is 58.6 kJ/mol.
VISCOSITY AND CHEMICAL COMPOSITION CHANGES OF HEAVY OILS AFTER MICROWAVE PROCESSING
Wang Shuangqing, Shen Bin, Lin Renzi
2010, 32(6): 615-620. doi: 10.11781/sysydz201006615
Abstract(1590) PDF-CN(900)
Abstract:
Based on intensive analyses of heterocomponents in heavy oils from the Liaohe, Shengli and Tuha Oilfields of China, a primary research on correlation between viscosity and chemical composition changes of original and microwave treated heavy oils was conducted. The results shew that the chemical composition of heavy oils was altered by a series of reactions under microwave processing, and the viscosity changed bidirectionally. The main microwave chemical reactions of heavy oils were cleavages of larger molecules into smaller ones, and were illustrated as follows: a) heterocomponents, especially oxygenated ones were decomposed prior to hydrocarbons by microwave radiation; b) the molecular distribution pattern of aliphatic and aromatic hydrocarbons remained unaltered under microwave processing, while that of heterocomponents was altered significantly, especially for alcohols and carboxylic acids; c) the chemical composition of heavy oils after microwave radiation was a comprehensive result of complex microwave chemical reactions varing in correlation to its original chemical nature, and was decisive for the direction and level of viscosity changes.