, Volume 27 Issue 4
    

  • Select all
    |
    第四届全国油气运移学术研讨会
  • A method for studying the oil and gas migration stages in superposed basin and its application.
    JIANG Zhenxue; PANG Xiongqi and HUANG Zhilong
    , 2000, 27(4): 25-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    After summarizing scholar's studies of petroleum migration at home and abroad, four methods for dating hydrocarbon migration period are summarized up. They are respectively tectonic analysis, reservoir organic petrology, diagenetic mineral isotopic dating and reservoir geochemistry-reservoir heterogeneity approach. Principles and application results of the four methods are generally introduced, including the application analysis for Turpan-Hami basin. Two periods for forming Pubei oil field have been identified by using the tectonic analysis and reservoir organic petrology approaches, which are, respectively, the period from late Jurassic to early Cretaceous and the late Tertiary. But the geologic isotopic dating indicates only the second migration period. The reason is that the sampling location is outside the oil-water interface controlled by the first migration period. The oil was thickened first and migrated later according to reservoir geochemical analysis for Lukexin oil pool. The results are very significant for hydrocarbon resource evaluation and exploration in Turpan-Hami basin.
  • Characteristics of natural gas migration and accumulation in the Upper Paleozoic of Ordos basin.
    MIN Qi; FU Jinhua; XI Shengli; LIU Xinshe; WANG Taoji and HONG Liyan
    , 2000, 27(4): 26-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Upper Paleozoic gas source rock of Ordos basin includes mainly coal measure source rocks and marine carbonate source rocks, which entered into gas-generating threshold in late Triassic, into gas-expulsing threshold in early to middle Jurassic, and reached gas generating and expulsing peak period in late Jurassic to early Cretaceous. The ancient abnormal overpressure of Upper Paleozoic at the maximal burial depth had played important role in natural gas migration and accumulation, and it was the main force of gas-expulsion through micro-fissure. Because the gas expulsion happened in relative late time, the primary gas migration was mainly in the way of disperse gas-expulsing and microfissure gas-expulsion. The abnormal high-pressure of great area appeared in Shihezi Formation of Upper Paleozoic during secondary gas migration period, which became pressure-sealing to prevent gas from its upward-cross migration and dispersion, while in local area the abnormal high-pressure of Upper Paleozoic strata provided dynamic to its downward-cross migration. Through the analysis of general control of regional tectonic evolution and paleo-fluid potential distribution on natural gas migration, it has come to the following conclusion that the relative low-potential area and low abnormal pressure area, which are adjacent to gas-generation center in geologic time period and located at structural high position, ought to be the most favourable area for gas accumulation and gas pool formation. The results of this theory have been confirmed by natural gas prospecting practice in this basin.
  • A study on the migration and accumulation of oil and gas in Qionghai uplift, Zhusan depression
    XU Xinde; HUANG Baojia; LI Li and ZHANG Minqiang
    , 2000, 27(4): 27-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    A lot of oil and gas traps and petroliferous structures have been discovered in Qionghai uplift. However all of them have no ability of oil and gas generation; and therefore it is very important to study origin of oil and gas for further exploration. Pool forming fluids exhibit heterogeneous distribution characteristics in this oil region. This characteristic is really an actual record of complexity in oil and gas migration and accumulation as well as pool forming. Starting from this viewpoint, heterogeneous distribution characteristics of maturation of crude oil, nitrogenous compounds, and properties of crude oil from Wenchang 13-2 oil field are analyzed in detail. On the basis of analytical results, the filling direction and filling stages are classified in great detail. Combined with regional geological information, the characteristics of oil and gas migration and accumulation in Qionghai uplift, Zhusan depression are thoroughly studied. The study recognizes that the oil and gas discovered so far are mainly originated from shallow lake shore source rocks in Wenchang Formation in Wenchang B sag, and 2 migration stages——Zhujiang era and Yuehai era-Quaternary stages are observed. The north slope between Qionghai uplift and transitional zone of Wenchang B sag is the necessary pathway for oil and gas migration, where existed conditions for oil and gas enrichment and development of non-structural traps; and which are the favorable places for further exploration.
  • Genetic analysis of YA13-1 gas field
    CUI Hu-she; TONG Zhigang and HU Gencheng
    , 2000, 27(4): 28-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Combined the geological and geochemical research results, the genetic analysis of YA13-1 gas field has been done by means of the basin modeling, from that we can obtain the following conclusions:①The evolution discrepancy of basin structure and the temperature & pressure fields of YA13-1 gas field in Ying-Qiong basin can be seen. ②The overpressure of YA13-1 gas field is a part of the Yinggehai's, which is resulted from several effects including the undercompaction, aquathermal pressuring and semectite dehydration. ③The No.1 faulted zone in YA13-1 gas field is a release zone for heat flow and overpressure fluid. It is also a migration pathway for fluid and hydrocarbon.④ The gas of YA13-1 gas field is from mixed sources, and the gas generated from the Neogene formation (late stage) or the Paleogene formation (early stage) in Yinggehai basin and the Paleogene formation (late stage) in Qiongdongnan basin.
  • Quantification of expulsed hydrocarbons from Tertiary mudstone source rocks in Qaidam basin and its prospective evaluation
    ZUO Shengjie; PANG Xiongqi; LI Jianqing and ZHOU Reinian
    , 2000, 27(4): 29-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Using the theory of hydrocarbon expulsion threshold (HET) and basin modeling method, the authors studied the characteristics of hydrocarbon expulsion, the amount and the efficiencies for oil and gas expulsion from Tertiary mudstone source rocks in the Qaidam basin. On the basis of the established standard charts for identification criteria of HET and quality evaluation for mudstone source rocks, as well as the contour maps of oil and gas expulsion intensity, the primary migration thresholds are determined to be about 1，500m for natural gas and 2，000m for oil. The results indicate the expulsed quantities of natural gas and oil are 10，672.1×1010m3 and 163.9×108t respectively. The mean expulsion efficiencies are 20 to 82% for natural gas and 10 to 64% for oil. The resources are preliminaryly calculated to be 16.4×108 to 24.6×108t for oil and 5，336×108 to 10，672.1×108m3 for natural gas, which indicate a bright exploration prospect for the studied region.
  • The control of palaeo-fluid-potential over migration of oil and gas in the east of Junggar Basin
    LIU Zhen; JIN Bo; HAN Jun; GUAN Qiang and LI Peijun
    , 2000, 27(4): 30-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    This paper presents the porosity evolution models in the east of the Junggar basin firstly, which accounts for the depth and age of layers. The palaeodepth and palaeothickness can be calculated by using these models. While the palaeopressure can be obtained through the improved Phillippone formula, and then should be rectified in accordance with the measured data. After the palaeodepth and palaeopressure are determined, the palaeo-fluid-potential can be obtained by using the formulas calculating the fluid potential. As the evolution of the fluid potential of oil-bearing sets in different time is studied synthetically, we could make the conclusion that the distribution of the fluid potential has a close relation with migration and accumulation of hydrocarbon in this area. But there is some difference in different strata and different belt. In a word, there is tendency of the migration in oil and gas from higher potential zone to lower potential zone and different types of pool have different relations with the potential field.
  • A study of the migration of oil and gas in intersalt non-sandstone formations in Jianghan Salt Lake basin
    SONG Yang; LI Chunmei and KUANG Lixiong
    , 2000, 27(4): 31-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Intersalt dolomites are both source and reservoir formations. Information shows that there are highly oil immersion body at the top of intersalt formations and multiple source shown by oil correlation that there are oils come from the bed underneath. Oil and gas accumulation are mainly controlled both by paleogeomorphology and fracturing belts. All these facts show that oil and gas migration do occur in the intersalt dolomites. An analysis shows that oil-gas pool forming in the intersalt formations is the result of actions of dynamic factors such as compaction, flotation, and capillary pressure etc, through four channel models: pore-throat in the intersalt formations, microfractures, dislocation of salt formations and combined effects of intersalt high pressure fluid piercement and intersalt faults. This means the pool forming experienced two main stages of intersalt undercompaction and intermittent high pressure microfracturing. Because intersalt reservoirs have rather low permeability, thus such migration are rather limited in scale and distance. Therefore the oil/gas reservoirs in this district have a characteristic of widely distributed oil immersion and the oil pools are not controlled by structures. The types of oil and gas pools formed are relatively simple. Mainly porous type reservoirs formed in some locally fractured belts. Finally some new ideas on oil and gas migration and accumulation are suggested according to the characteristic of oil/gas migration and accumulation efficiencies, which are primary migration efficiency of oil and gas in intersalt formations, flow efficiency of intersalt oil and gas, and pool forming efficiency of intersalt oil and gas, for them, various calculation procedures are suggested. This study gives a basis for the prediction of abundant accumulation belts and locations in the intersalt formations and the evaluation of oil and gas resources in dolomite formations.
  • Dynamical analysis of secondary migration of oil and gas in Jinhu sag, Subei basin
    CHEN Xian-he; LIU Qidong and YANG Xiaolan
    , 2000, 27(4): 32-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Jinhu sag is the second largest oil-producing sag in Subei basin. Its hydrocarbon enrichment varies largely in different zones. By analysis it shows that secondary migration of oil and gas have great effect on hydrocarbon enrichment degree. Hydrodynamic force and buoyancy are assumed the driving force in the paper. From the properties of oil-field water, underground paleocurrent type and analysis of fluid pressure system, it can conclude that the hydrodynamic force of the Jinhu sag is not the main action force to the secondary migration of hydrocarbon. Capillary resistance of conducting layers of Funing Formation in key time can be calculated from oil-water interfacial tension, radius of pore throat and wetting angle; et al. Compared it with buoyancy, it can derive out the critical driving condition of lateral secondary migration in second-order structure zone. It can also find out that continuous length of oil phase is far shorter than the width of petroleum zone. Shorter the critical oil length of zone, richer oil and gas it has. So, oil static buoyancy is the active force of secondary migration in the area. From this, the orientation of secondary migration and favorable accumulation part of hydrocarbon can be determined.
  • An approach to the multi-stage formation of oil-gas pools in Yurubcheno-Tokhomo accumulation zone of Siberian platform
    LI Guodu; JIN Zhijun
    , 2000, 27(4): 33-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    This paper gives a overview of the geological characteristics, under which the giant Yurubcheno-Tokhomo zone of oil and gas accumulation formed in the Riphean formation on the southwestern Siberian Platform. The formative process of Yurubcheno-Tokhomo zone is discussed through analyzing the Riphean,Vendian and Cambrian-Permian burial history. It is shown that the first time when oil and gas pools formed in Riphean formation is in the middle of the late Riphe, but these pools were destroyed or transformed at the end of Riphean period when the folding and uplifting movements occurred. The second hydrocarbon generation occurred from Cambrian to Permian periods. During these periods, although the area underwent differential uplifting movements with small scale and many large scale structures formed, the hydrocarbon generating of the source rocks continued, forming a number of pools. The basic magmatism during late Permian and Triassic had a significant influence on the generation and expulsion of oil and gas.
  • The analytical model of oil migration in water saturated media and result analysis
    KANG Yongshang; CHEN Lianming and ZHU Jiucheng
    , 2000, 27(4): 34-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    On the assumption that the geometrical shape of petroleum migration channel is regular, the distribution of permeability is well-proportioned and migration channel is water saturated, an analytical model of petroleum migration is established in order to evaluate the relationship between petroleum migration speed, quantity, distance and time under the situation of different migration channels. It can be obviously concluded from our research that, the higher the oil's viscosity is, the less the oil's migration quantity is; the shorter the migration distance, the slower the speed of petroleum migration and the quicker the decrement of migration speed. At the same time, the bigger the pressure difference is, the larger the oil's migration quantity is; the longer the migration distance, the faster the speed of petroleum migration and the slower the decrement of migration speed.
  • Experimental simulation of impacts of vertical heterogeneity on oil migration and accumulation in fining upwards sands
    ZENG Jianhui
    , 2000, 27(4): 35-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Experimental simulation was conducted by 2-D experimental models in order to study the impacts of reservoir vertical heterogeneity on oil migration and accumulation in fining upwards sands. The following results have been obtained: ① At a constant rate of oil injection, oil accumulates more easily in sands with moderate vertical heterogeneity (VH) than in those with severe VH. The oil-saturated sands makeup an increasing proportion of the total sands as VH decreases. ② At an injection rate of less than 1.0 mL/min, oil saturates all the sands comprising the fining upwards sands if VH is moderate, whereas oil charges only more permeable sands if VH is severe. ③ The threshold rate of oil injection, which is required to charge the least permeable sands in the fining upwards sands, is lower for sands with moderate VH than for those with severe VH. ④ At the injection rate of 0.1 mL/min, a shorter period of time and a less amount of oil are needed for sands with moderate VH in order to reach a steady state of oil migration and distribution. When the rate is greater than 0.5 mL/min, however, the result will be reversed.
  • The relations among the natural earthquake and structural fracture and oil-gas migration
    ZHANG Xingquan and AN Yuling
    , 2000, 27(4): 36-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Earthquake forms when crust under the stress is damaged promptly. The formation of structural fracture and fault (or fault remobilization) is closely related to the earthquake. The stress field of earthquake source is a part of tectonic stress field. The formation of structural fracture and fault is the result of evolution of tectonic stress field. Based on the research of earthquake and the forming time, the tectonic location, distribution and frequency of fracture can be studied. It can be concluded from the research that structural fracture has the best communication, which is the important pathway for the migration of hydrocarbon. The structural fracture parallel in direction to the maximum principal stress and the previous fault and fracture intersecting with the maximum principal stress at a small angle are the preferential directions of hydrocarbon migration.
  • Deep basin gas trap in the Upper Paleozoic of Ordos basin
    ZHANG Jinliang; CHANG Xiangchun and ZHANG Jingong
    , 2000, 27(4): 586-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The giant gas accumulations in Ordos basin found in low-permeability Paleozoic sandstones provides some of the best available information on basic characteristics of deep basin gas traps. The deep basin gas reservoir mainly consists of deltaic sandstone with varying amount of coarser sandstone and conglomerate. The numerous and mature coalbeds and organic-rich shales associated intimately with reservoir rocks throughout the region provide a prerequisite for deep basin gas accumulation. Gas generated in adjacent source rocks, moved vertically into the sand layers and then slowly migrated updip. This process lasted from late Triassic to late Cretaceous. This special form of deep basin gas trap defies conventional concepts of gas entrapment by turning them virtually upside down. Gas is trapped in the deeper part of the basin and is located in the downdip of an aquifer which outcrops mainly in northeast Ordos. The gas/water contact is really a wide belt, which marks the transition from downdip gas to updip water. Original gas accumulation pressures lie below the regional formation water pressure gradient. Gas-productive units in the deep basin are not controlled by local structure. An estimated 1.47×1012 to 10.5 ×1012m3 of gas in place are contained in the 15,000 km2 Upper Paleozoic gas accumulation.
  • Overpressured fluid fracturing, heat fluid flowing and episodic gas migration in the Diapir Belt,Yinggehai basin
    DONG Weiliang and HUANG Baojia
    , 2000, 27(4): 587-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The mechanism for overpressured fluid fracturing, its effects on hydrocarbon migration and its evolution process that involves in three stages of the formation of overpressured fluid-pocket, the uplifting-extending of “turtle shell” pattern and the fracturing-diapiring in the diapir belt ,the Yinggehai Basin are studied by the way of combing geological analyzing with numerical modeling. We investigate the tracers caused by heat-fluid flow that occurred during overpressured fluid fracturing, which are the abnormal responses of clay mineral evolution (X ray), vitrinite reflectance (Ro) and homogeneous temperatures of fluid inclusions and the geophysical characteristics of “gas chimney (gas wipe-out)” detected by seismic imagine. The data about heterogeneity of components and isotopic compositions of gases combined with fluid inclusions for the DF1-1 gas field located in the diapir belt can be used to trace and identify that the field were charged by at least three episodes of gases derived from deep Miocene source rocks. Therefore, We propose the model of episodic gas migration induced by overpressured fluid fracturing.
  • A numerical modeling of hydrocarbon generation and expulsion and the prospects prediction in pre-Jurassic formations in the Turpan-Hami basin
    YIN Ya-hui; PANG Xiongqi and SHI Xingchun
    , 2000, 27(4): 590-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    A modeling and analysis software of petroleum system―BasinView, developed by Platte River Associates, USA, was used to analyze geological, thermal, and hydrocarbon generation and expulsion histories in the pre-Jurassic formations, including Taodonggou ( P2 ), Cangfanggou ( P2-T1 ) and Xiaoquangou (T2-T3 ), in Turpan-Hami basin. Some results are concluded: Jurassic is the main hydrocarbon generation and expulsion period of pre-Jurassic source rocks; Total amounts of generated oil and gas in pre-Jurassic formations are calculated as 138.64×108t and 71.23×1012m3, and the total amounts of expelled oil and gas are 53.58×108t and 46.74×1012 m3, respectively, which indicate an oil expulsion efficiency of 38.6 % and gas expulsion efficiency of 65.6%; Oil and gas expelled from Taodonggou, Cangfanggou and Xiaoquangou source rocks took up 49.11% and 52.3%,7.64% and 8.99%, 43.25% and 38.71% of the total expelled oil and gas respectively. Taibei sag is the main prospect area for the exploration in pre-Jurassic formations in Turpan-Hami basin.
  • Modeling of hydrocarbon wastage amount in the process of pre-Jurassic hydrocarbon migration and accumulation in the Turpan-Hami basin
    SHI Xingchun; ZHOU Haiyan and PANG Xiongqi
    , 2000, 27(4): 591-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    In this paper, the hydrocarbon amount wasted during migration and accumulation is divided into five parts, which includes hydrocarbon retention amount in source rock, hydrocarbon retention amount in reservoir, hydrocarbon expulsion amount before the forming of regional sealing, hydrocarbon dissipation amount during migration and hydrocarbon amount destroyed by tectonic movements. Based on geologic analysis and study, calculation models of those five parts are constructed and applied to resource evaluation for pre-Jurassic in Turpan-Hami basin. The result shows that hydrocarbon retention amount in source rock is 5.438×1010t (oil equivalent) , accounting for 67.9 % of the amount of hydrocarbon generated; hydrocarbon retention amount in reservoir is 3.479×109 t , accounting for 4.47 % of the amount of hydrocarbon generated; hydrocarbon expulsion amount before the forming of regional sealing is 1.14×109 t, accounting for 1.466% of the amount of hydrocarbon generated; hydrocarbon dissipation amount during migration is 1.266×1010t, accounting for 15.27% of the amount of hydrocarbon generated; and the amount of hydrocarbon destroyed by tectonic movements is 9.653×109t, accounting for 11.4% of the amount of hydrocarbon generated.
  • Migration and accumulation of hydrocarbons in the central anticline belt of Dongying depression, Bohai Bay basin
    LI Pilong; ZHAI Qinglong; RONG Qihong; JIANG Youlu and TAN Lijuan
    , 2000, 27(4): 594-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Based on the geological data of the central anticline belt in Dongying depression, which is the largest typical multiple petroleum concentration belt in Bohai Bay basin of China, the petroleum migration and accumulation characteristics of this play have been discussed in the paper, and actions of fault on the migration and accumulation of hydrocarbons are also studied. The three kinds of model for the formation of oil and gas pools occur in the area. There are two main stages of petroleum migration and accumulation, and most of hydrocarbon pools formed in the later stage. The intense vertical petroleum migration process occurred many times in this play during Tertiary period, and a composite petroliferous play whose most of hydrocarbon pools are distributed along the faults formed.
  • Anomalous overpressure system of early Tertiary in Dongying depression and its petroleum geology significance.
    ZHENG Herong; HUANG Yongling and FENG Youliang
    , 2000, 27(4): 595-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Abnormal formation fluid pressure often exists in oil-gas bearing basin. With sonic log data and by means of equivalent depth method, the abnormal formation pressure and the residual pressure value of early Tertiary in Dongying depression are firstly calculated and studied in this paper. It indicates that development of overpressure system is related to undercompaction, smectite transferring into illite and petroleum generation. Overpressure system is the main driving force for hydrocarbon migration and accumulation. Hydrofracturing and episodic expulsion of hydrocarbon resulted from overpressure system are favorable for petroleum migration and accumulation. Petroleum is mostly distributed in the relative low-pressure area of the overpressure system. The plastic arch extension structure of central uplift area in Dongying depression is both the pressure release area of overpressure system and the very favorable area for oil and gas accumulation, in which the deeper formation ( Mid-Lower Es3—Upper Es4 ) is the favourable target of oil and gas exploration in the future.
  • Characteristics of oil pool formation in Gaoyou sag, Subei basin
    XU Jian and XIONG Xuezhou
    , 2000, 27(4): 598-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Lots of methods can be applied to studying characteristics of oil pool-forming. The methods selected to be applied to Gaoyou sag，Subei basin are pressure seal, characteristics of oil-field water and the changes of oil properties. Pressure seal layer controls the distribution of oil and gas. Pressure seal in Gaoyou sag can be divided into three types, namely single-sealed, double-sealed and non-sealed type. Because of difference of structure and sedimentary evolvement, the type and salinity of oil-field water have great differences both on plane and in vertical way. The changes of oil properties on the ground can indicate the orientation of migration. Migration coefficient，also divided into lateral and vertical ones，can also point out the orientation of migration. From the parameters listed above, the distribution characteristics and accumulation rule of oil can be forecasted effectively.
  • A Quantitative study on formation of gas pool in Shiwu fault depression of Songliao basin
    SUN Daming and LI Mingcheng
    , 2000, 27(4): 599-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The main method of quantitative study on formation of gas pool is the quantitative modelling of gas generation, migration, dispersion, and accumulation. Whether a hydrocarbon pool can form or not depends on its dynamic-equilibrium of accumulation and dispersion. If gas accumulation volume is greater than its dispersion amount, gas pool will form. On the contrary, it will not. Songliao basin is the largest continental-petroliferous basin of China. Based on a large amount of geological, geochemical, geophysical and engineering data on Shiwu fault depression of Songliao basin, studies of regional structure evolution, fault distribution, characteristics of depositional stratigraphy and trap characters of source rock, reservoir rock, cap rock and gas migration as well as their simulation matches are conducted in the paper. On the basis of these above, the quantities of gas generation, residue, diffusion, dispersion and accumulation are calculated by the means of new geological modelling and relevant mathematical modelling. From these results, we can get the possible largest accumulation quantity. The results of modelling confirm that gas pool at the regional structural high is a residual gas field, the amount of gas generated is large, but preservation condition is poor. From now on, the focal point of prospecting would be searching for various low-relief structural-lithologic gas pools, so that the study and prospecting of stratigraphic traps in lower places should be strengthened.
  • A comparison study on the effectiveness of using biomarker and nitrogenous compound as indexes indicating oil and gas migration
    LI Sumei; LIU Luofu and WANG Tieguan
    , 2000, 27(4): 604-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    A correlation study of pyrrolic nitrogen compounds with hydrocarbon compounds (mainly steranes and terpanoids) in oils generated from marine and salt-lake source rocks is carried out. Results indicate that differences in biomarkers of hydrocarbons between the two different types of oil are obvious; however, the difference in the distribution patterns of pyrrolic nitrogen compounds of the oils remain remarkably constant, indicating the impact of source organic matter and maturity on pyrrolic nitrogen compound is possibly lower than on hydrocarbon compounds. Results of oil migration study show that the migration fractionation effect of pyrrolic nitrogen compounds is larger than that of hydrogen compounds, and it is inferred that the difference is result from the strong polarity of pyrrolic nitrogen compounds. As a new kind of migration “tracer”, pyrrolic nitrogen compound has its advantage.
  • The vertical micro-migration of hydrocarbon and its near surface geochemical effect
    ZHAO Kebin; SUN Changqing and CHEN Xinhua
    , 2000, 27(4): 605-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The theoretical basis of petroleum geochemical exploration is vertical micro-migration of hydrocarbon. The migration is referring to the hydrocarbons of deep petroleum fields can pass through the cap and its overlying layers to near surface and form geochemical anomalies, which can be determine by modern precision instrument and differ obviously from background. On the basis of actual geochemical data from a petroleum development area of Ordos basin, the authors expound the vertical micro-migration evidence of hydrocarbon, inquire into near surface geochemical effect which is caused by the vertical micro-migration of hydrocarbon, build up effective discriminant model and apply it to oil and gas bearing prediction of geochemical anomalies in studying area, which has got a positive result.
  • An overview of hydrocarbon migration research
    LI Mingcheng
    , 2000, 27(4): 1369-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Oil and natural gas are both fluid mineral resources, the principal characteristic of which is their migration performance. Migration of oil and gas in the rocks is mainly a kind of geophysical action. The major problems of hydrocarbon migration research are the mechanisms of dynamics and kinematics, in other words, are the driving force, phase (or state), pathway and quantity. The driving force of primary migration is mainly abnormal high pressure and that of secondary migration is buoyance and fluid potential difference. The petroleum migration mainly in an oil phase, as for natural gas migration, it can occur in water-solution, oil-solution, free gas and diffusion phase. The most effective phase of hydrocarbon migration is in the oil phase or free gas phase, which directly forms the reservoirs without changing the phases. The pathway of primary migration is chiefly the microfissure, for the secondary migration not all permeable rocks are the pathways and have the characteristics of effective migration pathway and main flow direction. The fault posses the pathway characteristics in the initial stage of its forming and the deuteric seal is related to the diagenesis. The long-term active faults become the pathway of hydrocarbon migration. The gathering of the driving force and opening and closing of the pathway determine the episodic expulsion and episodic secondary migration, thereby determine the episodic injection and forming reservoir. This point has been confirmed by the reservoir geochemistry. The episodic flow of hydrocarbon migration and all geofluid and the episodic action of crust structure are complementary to each other and mutually determined. Since the hydrocarbon migration is a geological event occurring in the geologic historical process, the research method of it ought to be the dynamic analysis and synthesis. Owning to many problems on hydrocarbon migration theories and research methods at present, it is a burning issue of the moment to strengthen the foundational theory research, synthesize the migration and accumulation rules of all types of basin and improve the level of computer and laboratory simulation.
  • Quantification of petroleum secondary migration distances: fundamentals and case histories
    LI Maowen
    , 2000, 27(4): 1370-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The study of petroleum secondary migration (particularly the quantification of secondary migration distances) is one of the most critical but least understood facets in petroleum geology. During secondary migration, organic compounds containing functional groups selectively partition between the migrating oil phase and immobile solid rock matrix through the formation of either hydrogen bond or other ionic bonds. Pyrrolic nitrogen compounds represent one of the most promising candidates as molecular tracers for secondary migration distances. However, a constant relationship between pyrrolic nitrogen composition and absolute migration distance of an oil should not be expected. As organic source inputs and thermal maturation may potentially alter the nitrogen parameters, an independent cross-fraction and multi-parameter assessment of these factors should be done before these data are used to compare relative migration distances of different oils. Case histories from the Alberta and Williston basins in Canada, Bohai Bay and Tarim basins in China demonstrate that the proposed nitrogen migration tracers are generally applicable in different types of sedimentary and tectonic settings, but the validity of these parameters should always be verified by other geological-geochemical data.
  • Oil and gas accumulation related to evaporite rocks in Kuqa depression of Tarim basin
    LU Xiuxiang; JIN Zhijun; ZHOU Xinyuan and PI Xuejun
    , 2000, 27(4): 1371-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Very thick gypseous salt formation developed in both Upper and Lower Tertiary, both of them have an important effects on the oil and gas accumulation in this depression. 3 sets of sealing and reservoir formation assemblie related to the evaporite rock developed:①thick Cretaceous sandstone and its overlying Lower Tertiary salt formation;②Jidik sandstone in Upper Tertiary and its overlying evaporite formations; and ③interbedded sand- and mud stones in Kangcun-Kuqa Formation over the evaporite formations. Structural deformation in Kuqa depression area rather strong and oil types of traps are mostly related to faults in Kuqa depression. There are mainly two types of trap:①compressional (faulted) anticlinal traps underneath salt zone, where Triassic, Cretaceous, Jurassic and bottom Tertiary sandstones have reservoir properties; and ②tensional (faulted) anticlinal traps above salt zone, in which formations having reservoir properties are Kangcun and Kuqa Formations. Two types of oil/gas accumulation model are found above and beneath the salt formation, i.e., arched anticlinal oil and gas pools above the salt formation and compressional anticlinal gas pools underneath this salt formation. While faults are main pathways for the migration of oil and gas generated from Triassic-Jurassic source rocks into these pools. Gas predominately accumulated underneath this salt formation.
Office Online
Included
Most Popular
Links More
Visited
    Total visitors:
    Visitors of today:
    Now online:
Copyright © Petroleum Exploration and Development
Address:P. O. Box 910, No.20 Xueyuan Road, Haidian District, Beijing 100083, China
Powered by Beijing Magtech Co. Ltd.