, Volume 29 Issue 3
    

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    石油地质研究
  • An analysis for oil and gas migration and accumulation history in Jurassic system, Taibei sag, Turpan-Hami basin
    WANG Zhenliang and CHEN Heli
    , 2002, 29(3): 196-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    On the basis of distribution and evolution of paleo-hydrodynamic influencing hydrocarbon migration and accumulation, it is set forth about periods, scopes of expulsion from source rocks, directions of secondary migration and the distribution of profitable convergence areas in reservoir rocks, and the history of accumulation and pooling in Taibei depression is analyzed and summarized. It is discovered, the main periods of expulsion in coal-measure source rocks of lower and middle Jurassic series is early Cretaceous epoch and Pliocene up to now respectively, and the high efficiency of expulsion in middle and eastern areas is developed during early Cretaceous epoch, in contrast, in middle and western areas is Pliocene up to now. The distribution and evolution of fluid potential is of succession. By the way, the relatively low potential areas among high potential areas and those parts located in periphery of high potential areas are directions of secondary migration, and the former is divided into three types—most profitable, profitable and fairly profitable, based on the conditions of migration and accumulation. According to the history of hydrocarbon generation and expulsion, evolution of fluid pressure and fluid potential, the behavior of hydrocarbon in Jurassic system is divided into two major phases of accumulation and pooling in Taibei depression, i.e. phase of early Cretaceaous epoch and Quaternary Period respectively. During the first accumulation stage, the behavior of hydrocarbon is mainly occurred in middle and eastern part of the depression, and the directions of secondary migration and most profitable accumulation areas are Xiaocaohu, Qiudong and their adjacent areas, where at second accumulation stage, active accumulation is mainly developed on middle and western part, and the former existed oil and gas pool is to be remold and complement to some extent.
  • Oil and gas accumulation process in Daqingzi region of southern Songliao basin
    WEI Zhiping; MAO Chaolin; SUN Yan and MIAO Hongbo
    , 2002, 29(3): 197-0.
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    In this paper, the author studied the main forming time of Gaotaizi oil reservoir and the period of accumulation of oil and gas of Heidimao structure in Daqingzi region, besed on the research results of reservoir's organic inclusions, the history of generation and discharge of hydrocarbon, the evolution of structure, and the conditions for oil and gas migration and accumulation. The petroleum accumulation occurred mainly at the end of Mingshui period and Tertiary. The reservoir's organic inclusions have high abundance in this time; they recorded the main period of petroleum accumulation.
  • History analysis of petroleum reservoir fluids—Taking Sanma area in Huanghua depression as an example
    ZHONG Ningning; ZHANG Zhihuan and SUN Xiaoming
    , 2002, 29(3): 198-0.
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    By means of fluid inclusion mineralogy, it has been made that a trial of reconstructing reservoir fluid history for petroleum accumulations within the lower section of Eocene Shahejie Formation in San-ma area, Huanghua depression. Analysis of the state of fluid trapped in inclusions revealed that the reservoir fluid was trapped while temperature was around 100－140℃, with high density and high salinity. The charge of the hydrocarbon fluid was likely to occur during the period of Neocene Minghuazhen Formation deposition in 10－4Ma ago. The salinity of water below the OWC has probably changed as a result of a small scale structural uplifting following oil charge. Consequently, comparing with the pristine sample of reservoir fluid trapped within fluid inclusion, there was an obvious decrease in salinity for the current formation water.
  • The distribution and significance of abnormal pressure in Upper Paleozoic of Huanghua depression
    WANG Shuxiang; YU Xueming; HE Yongmei and LI Yanhui
    , 2002, 29(3): 199-0.
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    The analysis results of acoustic data from the Upper Paleozoic strata in Huanghua depression suggest that there are two overpressure intervals within Permian—Carboniferous strata: Carboniferous strata and Shiqianfeng Formation of top Permian strata. Horizontally, the overpressure in coal-measure strata developed in the whole Huanghua depression, and southern region overpressure is stronger than the central. The mechanism to develop overpressure is mainly due to differential compaction, generation of hydrocarbon and clay transformation, according to the analysis of overpressure thickness and depth. The significance of existence of overpressure is to form high-quality regional seal strata that can be favorable to preserve Paleozoic petroleum system. In addition, factual data suggest that the overpressure slows down the evolution of source rocks in Paleozoic strata: obvious in 0.8%-1.05% of Ro with low influence in high temperature stage. This lag effect of hydrocarbon evolution caused to late generation and migration, which increase the probability of reservoir formation including all traps that formed from Paleozoic to Tertiary. Therefore, there are all kinds of reservoirs: Paleozoic reservoir with Paleozoic source; Mesozoic reservoir with Paleozoic source; and Paleozoic reservoir with Cenozoic source, which enlarged the prospecting region that migrate from Paleozoic source rocks.
  • Subtle reservoir of Paleogene in Sanchunji of Dongpu sag
    ZHANG Jianjun; ZHANG Yanhong; ZHANG Qilin and CHEN Dingcai
    , 2002, 29(3): 200-0.
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    The structural zone of Paleogene in Sanchunji of Dongpu Sag is complex and the exploration of the high in the uplift is worse than that of the east slope, thus subtle reservoir may be formed in this area. During the early-mid Tertiary, the Lower Tertiary structure was fixed, oil and gas generated by the source rock of Upper Sha4(Es4)-Low Sha3(Es3) migrated to the west of Guyang depression through fault, but the amount of hydrocarbon generated is limited, and accumulated in the lithologic trap of reverse roof in downthrow block of Chundong fault. It is predicted that predict this structural zone is favorable for progressive exploration for subtle reservoir.
  • Sealing analysis of growth fault
    LIU Dongzhou; LIU Bin; LI Jianying; WANG Jin and CHEN Hongtao
    , 2002, 29(3): 201-0.
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    Growth faults have special fault plane form in their initial phase during which the displacement of the two blocks creates two kinds of stress states pore belt and sealing belt. It is easy to produce ductile flow in the undercompacked shale of the two blocks to create deformentation and then to form muddy sheared zone, which is the origin to form the muddy smearing belt of the growth fault. The formation of the muddy smear has close relationship with fault throw, lithologic composition feature and mudstone content. The growth faults are the second or the third order faults in the basin, which extend a long distance in their strike. They have different throw in the different segements of the same horizon, and different lithologic assemblages in the hanging and downthrown blocks of a fault, which makes the sealing having the segmented feature in the fault strike. It is necessary to analyze the sealing to growth fault relation as a whole and segmentedly and then in different horizons of a particular sector to analyze the throw variation pattern and the lithologic assemblage feature and finally, compare and evaluate the strong and weakness of the muddy smear in each section as well.
  • The study on the clastics reservoir of the Carboniferous in the northwest of China
    ZHU Rukai; GUO Hongli; HE Dongbo; LUO Zhong and SHAO Longyi
    , 2002, 29(3): 202-0.
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    The coal-bearing rocks during Carboniferous deposited in marine and land transitional environment in Qilian area. The deposits are carbonate and clastics during early Carbonferous, which are subabyssal and abyssal gravity current deposits during late Carboniferous in Liuyuan area. The deposits are terrigenous clastics, marine clastics, carbonate and pyroclastics in the north of Xinjiang area. The clastics during Carboniferous period are medium arkose, lithic arkose, litharenite and feldsparthic litharenite in the north of Xinjiang area; which are quartzarenite, subfeldsparthic litharenite, litharenite and arkose in the Qilian area. The stage of diagenesis is telodiagensis A-B, C, and locally it is at metamorphic stage. There are intergranular pores, intragranular pores, intercrystalline micropores of kaolinite and fractures. The reservoirs are of lower porosity-lower permeability. There are fewer primary pores because of its strong compaction in the north of Xinjiang area. There are better reservoirs where is near the zone of weathering in Qilian area. The better reservoirs of Upper Carboniferous are distributed in Wucaiwan area of northeastern Junggar basin, Shuangjingzi area of Qitai region and Chepaizi and Baikouquan areas in western Junggar basin and Xiaheyan block of Zhongwei area, Hongshuipu block of Jingtai area, and so on of Qilian region. The better reservoirs of the Lower Carboniferous are distributed in the Shuangjingzi area of northern Xinjiang and Hongshuipu area in Qilian region.
    • 综合勘探开发技术
  • Microbiological prospecting for oil and gas in Manite depression of Erlian basin
    YUAN Zhihua; MEI Bowen and SHE Yuehui
    , 2002, 29(3): 203-0.
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    The microbiological prospecting for oil and gas (MPOG), was applied to the oil and gas exploration of Hariga structure, Manite depression in Erlian basin, with the survey grid of 750m×750m. Microbiological analysis and marking the abnormal extent were done by MicroPro laboratory of Germany.The structure was divided into 3 abvious oil prospective areas according to abnormal oil distribution law disdinguished from microbes. 2 exploration wells were drilled in pilot test unit. Compared data from MPOG with that from existing 2 wells, MPOG has excellent result with 100% successful ratio.
  • Mid-shallow formation precise exploration in highly explored Guandong area
    LIU Zicang; WANG Donglin; WEI Ajuan; WU Xuesong; GUO Jinfeng; YU Chao; XIAO Yuyong; TENG Zhongjie and ZHOU Baoxian
    , 2002, 29(3): 204-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    It is difficult to prospect for shallow and middle reservoirs at late exploration stage in Guandong area. Since 2000, the block was studied again, some best exploration achievements were made and a high-quality reserve block of ten million tons was found. This breakthrough was made because of followings:(1)timely analyzing the exploration and production information; (2)perfectly integrating seismic and geological studies; (3)applying multiple technologies, such as precise strata correlation, precise structural interpretation, precise trap identification, applying advanced technical methods in reservoir prediction; and (4)optimizing deployment programs and reducing exploration risk. The successful exploration experience in Guangdong block suggests that with the improvement of the science and technology level this highly explored block still has a big potential of petroleum exploration.
  • A new approach to seismic inversion of elastic parameters for VTI media
    DU Liying; DU Lijuan; XIAO Qianhua and GAO Jinhui
    , 2002, 29(3): 205-0.
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    In this paper, seismic inversion of elastic parameters in horizontally layered VTI (transverse isotropy media with vertical symmetry axis) is well studied, on the basis of seismic wave kinematics theories in transverse isotropic media with vertical symmetry axis. The reflection travel time of P-P wave deviates from hyperbolic greatly, especially for relative long spreads, so the travel time can be approximated more exactly by three terms Taylor series than by two-term Taylor series. However P-wave reflection travel time formula in the weak anisotropy hypothesis can be approximated at the highest precision even in relative moderate or long spreads. For the P-SV wave travel time, it also can be expressed exactly by a three-term Taylor series in short or moderate spreads. The three term Taylor series of P-P wave or P-SV wave reflection travel times in VTI media are the function of elastic parameters. Therefore they can be used to inverse the seismic elastic parameters. When elastic parameter inversion is done, it is known that when the maximum source-receiver distance is 1.5 times Interface depth, coefficients of three-term Taylor series could be gotten accurately, the elastic parameters including vertical velocity of P-wave, vertical velocity of S-wave and dimensionless elastic anisotropy parameters
    • 油田开发与油藏工程
  • The simulation models of remaining oil distribution at super-high water-cut stage of Shengtuo oil field
    SUN Huanquan; SUN Guo; CHENG Huiming and WU Suying
    , 2002, 29(3): 206-0.
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    Shengtuo oil field has been developed under water flooding for 36 years. Now it is at super-high water-cut stage with 95% of composite water cut and its remaining oil is scatteredly distributed. It is difficult to improve oil recovery. Based on the examination results of a large amount of oil-bearing sandstone thin sections, the authors advance 5 kinds of model of the micro distribution of remaining oil at super-high water cut stage. By using the visualization technology of 3D data field, fractal theory and new computer graphical and image processing techniques, the simulation models of the distribution of remaining oil, which can be used to bring to light the formation mechanism and distribution pattern of remaining oil, were built up.
  • Feasibility analysis for shortening test time of low permeability reservoirs
    SHI Zhongqian and YANG Shengde
    , 2002, 29(3): 207-0.
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    Jingnan oil field of Changqing oil field complex is a typical low permeability reservoir in the Ordos basin. Its average permeability is only 1.6×10-3μm2, and average output is 4.5t per day per well. In 1996, it was put on stream. At the initial test of the well, the pressure built up very slowly. It took a long time to test the radius directional flow and in most wells, which were tested, there were no obvious show of it. It not only affected the output, but was also difficult to collect the data. In 1999, a feasibility study of shortening the test time began. After more than one year, the stage achievement was available. It shows that in Well Chang 6 of the main reservoir in Jingnan oil field, the permeability is very low and it is feasible both in theory and in practice to shorten the test time. On the spot test, it only needed about 20 days to test the well and its result of the datum interpretation can also meet the needs completely. Meanwhile, just before this field came on stream, the reservoir was acid fractured, whose value of CD e2S didn't get to 0.001. In the common interpretation, it will be good enough when the straight line appears and will not test the radius directional flow any more. This article utilizes a mass of the spot test information to analyze and research the feasibility of shortening the test time.
  • Application of horizontal well technology in the development adjustment of segment bottom water oil reservoir in Ng2, Block Lin 2
    XIONG Min; LIU Chuanpeng and SHAO Yuntang
    , 2002, 29(3): 208-0.
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    With the progress of development technique of oil field, the production technology of horizontal well is getting more and more perfect. It brings into obvious economic benefit, especially for bottom-water oil reservoir, vertical-fissure oil reservoir, heavy oil reservoir and less permeable oil reservoir.Ng2 of Block Lin2 is a typical bottom-water oil reservoir in Linpan oil field. It has entered a high water-cut period of development, having been developed over 20 years with vertical wells. The effect of development and adjustment with vertical wells is not relatively well, as a result of bottom water coning more seriously and water-cut rising faster. Therefore, it was decided that Guan 2 bottom-water oil reservoir of Lin2 block was developed and adjusted with horizontal wells. 8 horizontal wells have been designed, on the basis of research on the characteristic of oil field development and the distribution rule of remaining oil. After putting into production, the effect is comparatively well, showing a high initial production and low water cut. Oil production rate of the fault block has greatly been increased; recovery factor has been raised from 34.7% to 45.4%. An average increases of 35,000t of recoverable reserves per well has been obtained which is equal to over 3 times of vertical well. The development effect is perfectly well. It is provided with instruct signification to the development adjustment of the similar bottom-water oil reservoir in the later period of high water cut.
  • Analysis and prediction of scaling mechanism of the CaCO3 from oilfield injection waters
    YIN Xianqing; WU Jiazhong and WANG Zhengliang
    , 2002, 29(3): 209-0.
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    The CaCO3 scaling is the main scaling type of oilfield injection waters, which seriously affects the oilfield development effectiveness. By means of scaling experiments and core flooding under the different temperatures for four types of water, scaling mechanism of CaCO3 is studied and predicted theoretically. The results show that: (1) The scale is serious for oilfield injection water, which rises with the temperature but turns worse, when Ca2+ and Mg2+ descent rates amount to 52.3% at 90℃; (2) Core flooding experiments show that CaCO3 crystal can precipate in core pores and at the surface of pore throat; (3) The treated water is in the steady area of CaCO3 solubility, the water quality is stable, so this water can't produce the CaCO3 scale and (4) Theoretical prediction is consistent with experiment result.
    • 油田非注水开发
  • An approach to the economical development model of thermal recovery of heavy oil reservoirs
    HOU Jian; YU Bo; CHEN Yueming; SHI Jun and ZHANG Wei
    , 2002, 29(3): 210-0.
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    With oil field development moving into market, research on economical development model is become necessary. This paper puts forward a conception of economical development decision-making factor and its calculation method. Based on discussion of the relations among limited OSR, oil price and oil yield, parameters such as economical limited OSR, single-well daily economical boundary production rate and so on are calculated. It can be seen that the limited OSR is gradually reduced along with the increase of oil price and (or) oil output but its extent decreases. In the condition of high oil yield, the degree of limited OSR's sensitivity to oil price is rather smaller than in the condition of low oil yield. At the same time, on the basis of numerical reservoir simulation of Ji 32 fault block in Erlian oil field, continued soak production mode and rational conversion production modes are studies. Taking economical factor into account, ultimate recovery is related with oil price. Converting the current steam soaking into the intermittent steam injection is the optimum production mode; its forecasting ultimate oil recovery is increased by 3% than continued steam soaking.
    • 油层保护与改造
  • The research and application of FracPac technique in Shengli oil field
    XIE Guixue; LI Xingchuan and DU Baotan
    , 2002, 29(3): 211-0.
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    FracPac is a new sand-control method, which is quite different from conventional methods. It acts as a technical measure both in sand-control and of stimulation. In this paper, the sand-control mechanism of packed fracture and FracPac plan design method and field tests were summarized based on the studies about the effect of fracture on reducing or avoiding damages of rocks, researches about the effect of fracture on reducing the capacity of fluid moving with micrograins and the experiment and field test results about the effect of packed fractures on mechanically bridging formation micrograins in Shengli oil field, China, and some comments for improving this new technique were given. From the results of studies, the authors hold that this technique is a method with distinctive advantages and great application potentiality.
  • Possibility study on multi-fracture creation during artificial hydraulic fracturing
    LIU Jianzhong; WANG Xiujuan; SUN Yuling and PAN Yong
    , 2002, 29(3): 212-0.
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    The shapes of hydraulic fracture are very crucial to the results of fracturing treatment, with the primary consideration of fracture shapes. Stress concentration around the wellbore becomes much complex when the quality of well cementing is improved and the well depth is increased, which makes the stress concentration around the perforated wellbore important enough to be noticed. Each perforation can become single fracturing source, and stress concentration difference from different perforation orientation will affect the process and shape of artificial fractures, and the possibility of multi-fracture also exists. In this paper, the stress concentration around the perforated casing is analyzed, and the resistance against fracture propagation and the priority of artificial fracturing during each perforation treatment are discussed. Meanwhile, the influence of stress states on fracture shape and the relationship between the initial fracture shape and perforation orientation is elaborated. Several conclusions are reached based on the testing results of underground stresses in Lasa oil field of Daqing, and the analysis of artificial fracture shape under the condition of deep perforation. If the perforation orientation is stochastic, the possibilities of vertical initial fracture and horizontal initial fracture from 800 to 1200 meters of depth are approximately the same, without obvious difference between both fracturing pressures, and multi-fracture may be created during one treatment. The artificial initial fracture shape can be controlled by proper perforation orientation. And the original shapes of initial fractures can be maintained during propagation for the minimum horizontal stress is about equal to the vertical principal stress.
    • 综合勘探开发技术
  • A study on saturation-resistivity distribution pattern of reservoirs——An in-depth analysis for the basic origin of low resistivity reservoirs
    OUYANG Jian
    , 2002, 29(3): 410-0.
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    Research is conducted on the distribution law of resistivity-saturation in good quality reservoirs using capillary pressure theory, petropysic data, and a great number of case statistics for various oil fields. The research shows that there are some factors, such as density-difference between oil and water, height above level of free water and pore structure in reservoir, control the distribution law of saturation-resistivity. Based on the research,the major background conditions with more details that may cause low resistivity pay zones in middle and shallow depth in Bohai Bay area were analyzed. The most low resistivity pay zones that have been counterchecked and explored in recent years can be attributed to some special reservoirs, in which the density difference is small (i.e.0.1-0.15g/cm3), the reservoir height is small (i.e.10-20m), and even it may be smaller than 10m. In these special reservoirs, oil saturation is so low that it can be 50-60%, and resistivity ratio could be 4-6.3(comparing with adjacent water-bearing beds). Under this condition, and combined with other factors like invasion of mud filter and poor pore structure etc, oil-bearing reservoir with low resistivity may be formed. If lateral log is run under the condition of mud based fresh water, the difference between oil-bearing and water-bearing formations will be smaller. Most oil-bearing reservoirs that have been discovered in recent years belong to the special one describeb above. All results in the research will be helpful for detecting low resistivity pay zone.
  • The oil/gas reservoir types in Wuerxun-Beier faulted-downdepression and their exploration methods
    ZHANG Jiguang; PENG Suping; ZHANG Baoxi and LIN Jingye
    , 2002, 29(3): 411-0.
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    Wuerxun and Beier faulted depressions are located in Hailaer basin, which are the thickest in sedimentary rocks and largest in area in that basin. They have various oil and gas reservoir, which can be classified into three major types (anticlinal, fault-block and stratigraphic-lithological reservoirs) with ten kinds according to the analyses on the conditions for the formation of the reservoirs and their distribution feature. The scale of oil/gas accumulation and their richness for different reservoirs are different due to difference in the conditions for their formation. Based on this the exploration model suitable to complex oil/gas reservoir exploration is put forward, which includes using progressive exploration and development method to evaluate oil/gas reservoirs and making actively better use of 3D seismic exploration, carrying out trap description of oil/gas reservoir, identifying oil/gas zone in wellbore, stimulating oil/gas reservoirs and adopting other necessary technologies.
  • New method for well log interpretation by single fluid flow unit
    WANG Yuelian and SONG Xinmin
    , 2002, 29(3): 414-0.
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    The traditional well log interpretation sometimes cannot get satisfactory results because it takes several different sand bodies as one unique interpretation unit, and the difference in permeability among the fluid flow units is not taken into account. On the understanding of the microscope feature of the pores in reservoir rocks, this paper proposes a new method to get more accurate well log interpretation result, which takes the fluid flow unit as the basic interpretation interval. By modifying the Koney-carman equation and using the sorted from term of the average flow radius, four parameters sorted from the reservoir property are used to define and characterize the fluid flow units of one sand body in Daqing oil field. A good correlation of porosity and permeability in each flow unit is gotten and then used to build the interpretation module from porosity to permeability. The petrophysico-electrical relationship from the laboratorial data is used to define the interpretation module for water saturation. It is concluded that the result from this method is more satisfactory than traditional ones by comparing with the laboratorial data.
  • Stochastic facies modeling constrained by high-resolution seismic data
    ZHOU Liqing; ZHAO Limin; ZHAO Guoliang; MU Longxin and JIA Ailin
    , 2002, 29(3): 415-0.
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    Taking the Reservoir Z, F oil field, Venezuela as an example, this paper illustrates the application of logs data to constrain seismic data for producing a high-resolution acoustic impedance 3D model. The high-resolution 3D data from stochastic seismic post-pack amplitude inversion and logs data are then used to constrain facies modeling process, which reduces the uncertainty of models greatly. Realizations for porosity and permeability are obtained by modeling constrained by facies. The realization which honors the production performance is selected after the up-scaling and streamline simulation. Streamline simulation, using petrophysical parameters models, shows good agreement with water injection behavior.
    • 油田开发与油藏工程
  • A study on water-injection mode of low-permeability reservoirs
    WANG Xueli; DUAN Hehai; SHI Huandian; LI Xiaoliang; WANG Qingkui; LU Yongping and MA Huicai
    , 2002, 29(3): 418-0.
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    The reservoirs in the southern Dagang oil field are of low permeability with a large number of micro pores. After water injection, water cut in producing wells rose very fast and complicated the production operation. Through analysis of intermittent water injection theory and introducing domestic and international experiences, the super small intermittent water injection was applied in two pay zones, Nv20 and Nv34 in Shenvsi oil field in 1998. Later on the effect of different cyclic time and frequency and water cut on oil exploition was studied. The considerable numbers of experiences have proven that. (1) Super small cyclic flooding can take advantage of much more beds. (2) Super small cyclic water injection is suitable for water-injection wells; the corresponding production wells resulting in considerable reduction of associated water volume and stabilization of production water cut at 60% level. (3) The super small intermittent water injection is an effective economical method, especially in low permeability reservoirs.
  • A study on deep condensate gas well inflow performance equation
    YU Xichong; ZHAO Jinzhou; WU Yaling and ZENG Yuanqi
    , 2002, 29(3): 419-0.
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    In this paper, a new method is brought forward which is suitable for condensate gas flow state. The new method bases on the flow character of natural gas and the petro-condensate liquid in the formation, combining with phase state theory of condensate gas. At the same time, the change of the liquid phase and the components and the various skin factors under different condition are also considered. The two-phase pseudo-pressure function of the theory of stable state is used. A new equation is adopted to calculate the well bottom flow pressure. For these method and concept, the mathematics model for three different situation:First, well bottom flow pressure is higher than dew point pressure. Second, well bottom flow pressure is lower than dew point pressure but condensate oil saturation lower than flow saturation. Last, well bottom flow pressure is lower than dew point but condensate oil saturation higher than flow saturation. Developing the relevant software to compare with the result of well test, the new method is suit for the forecast of the influx state in condensate well.
  • The application of BP network to oil field measure program
    CHEN Ling; FENG Qihong and YU Hongjun
    , 2002, 29(3): 422-0.
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    During the later period of oilfield development some measures must be taken in order to stabilize the oil production and to control the water cut. The conventional method of programs of measures contains some error. Based on the BP network, this paper presents a new model which establishes the relationship among oil production, water cut and measures. This model can predict the contribution of the measures to the oil field. Base on the lowest cost per ton of oil production as the objective function, the optimal programming model is presented in this paper. This model can realize the optimal disposition of measures by Monte Carlo stochastic simulation method. This model has been applied to Cunhua oil field. The applied result shows that this method is effective and reliable.
  • Development and application of integrated management system for casing damage well
    WANG Yongdong; XU Guomin; HE Guixin and LI Xi
    , 2002, 29(3): 423-0.
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    At present, there are over 1000 casing damage wells in Daqing oil field. Casing damage not only destroys seriously injection-production balance of oil field, but also restricts further adjustment of injection-production structure of oil field. In the paper, at first according to the casing damage features of Daqing oil field, casing damage conditions and production practice, we clarify the necessary and importance of developing an integrated management system for casing damage well. Then composition and function of integrated management system for casing damage well are introduced, and we describe in detail the mathematic model of economic evaluation which can optimize and combine big repair technical measure for casing damage wells. Taking Xingshugang oil field in Daqing oil field as example, using mudstone creep theory and Mesais rule, casing damage mechanism of Xingshugang oil field is determined. In the end, the popularization and application results of integrated management system for casing damage well are introduced. Successful development of integrated management system for casing damage wells provides a theoretical basis for engineering technical staffs to analyze the cause of formation for casing damage and work out an economic and reasonable integrated treatment project, improve work efficiency of casing damage well management, gain better economic and social benefits.
    • 油田非注水开发
  • Numerical simulation study for improvement of polymer flooding by viscoelastic effect
    LI Hong; CHENG Linsong and ZHANG Shuyu
    , 2002, 29(3): 428-0.
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    In this project, based on laboratory research, constitutive equation of viscoelastic effect was determined, the critical Deborah number and the critical viscoelastic velocity were selected to be threshold values, that is, viscoelastic effect would happen when polymer solution flows through porous media, if the critical Deborah number or the critical viscoelastic velocity is exceeded. All these done helped establish the numerical simulation method of viscoelastic effect and made it possible to improve the software of polymer flooding successfully. Using the improved software and by the means of numerical simulation, changes which viscoelastic effect could make of polymer flooding were studied, and finally made conclusions that profile control and mid-low permeability oil layer potential development play important roles in recovery increment, meanwhile the improvement of flooding efficiency also can not be overlooked.
  • Flow rules of Xanthan solution in porous media and their effects on enhancing oil recovery
    ZHANG Hongfang; WANG Demin and WANG Lijun
    , 2002, 29(3): 429-0.
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    The rheological behaviors of Xanthan solution in a rheometer and in porous media as well as residual resistance factors are measured through experiments. Oil displacement experiments are proceeded with various concentration, injection speed and core permeabilities. The results show that with the concentration increase of Xanthan solution, the bulk viscosities increase, but residual resistance factors increase only when the concentrations are above overlap concentration, and in this case the depleted layer thickness, the apparent viscosities and the extent to enhance oil recovery do not vary much. Compared with the situation that concentration is lower than overlap concentration, recovery remains a higher amount, so that the optimal concentration for Xanthan displacement should be a little higher than overlap concentration. The residual resistance factors and the depleted layer thickness of Xanthan solution decrease with injection speed increase, but recovery does not vary much. The increase of permeability can increase recovery. What can increase recovery is the increase of the force parallel to oil-water interface generated by the increase of apparent viscosity or the decrease of depleted layer thickness, which is the results of the overlap of Xanthan molecules.
    • 海外油气勘探开发
  • Sliding feature of the transforming Muglad basin
    FAN Yingfeng; CHANG Heng; LONG Xiang; WANG Lizhi; WANG Reixia and DENG Yixun
    , 2002, 29(3): 436-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Muglad basin, in the middle of Africa, is a continental transforming basin lying in the south of the eastern middle part of the Central African fracture system. Rift belt of the northern edge of the basin mainly has a shear-sliding feature while both NGL depression in north part of the basin and KK depression in south part of the basin mainly have a strike-sliding feature. The south and north parts of the basin misplaced obviously in the left and between the two parts occurs an east-west striking regulator transforming structure belt nearly parallel to the sliding fracture of Central Africa. The right sliding movement of the huge Central African fracture in early Cretaceous resulted in west dipping faults in depression boundaries of the main body of Muglad basin with all the depression faulting in the east and overlying in the west, late Cretaceous thickening in the east and thining in the west. The huge Central African fracture slipping to the left in late Cretaceous reformed Muglad basin and an east dipping fracture system appeared with a NNW strike and halfgraben in the north and graben in the south. The Cretaceous sedimentation rate is high with good oil generating condition because of the slipping of Muglad basin. Subsiding center transferring from north to south created clean mudstone of Darfur group of KK depression in south part of the basin. But Muglad basin has a low geothermal gradient with a low development degree for igneous rock.
    • 石油地质研究
  • Reservoir-forming history of Ordovician reservoir at Well Tazhong 45 in the northern slope of Tazhong uplift
    LIN Qing; WANG Peirong; JIN Xiaohui and LIN Renzi
    , 2002, 29(3): 452-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The difference of sterane and terpane distribution indicates that the source of Tazhong 45 well Ordovician reservoir oil is different from the other oil of Tazhong 10, 11, 35 well on the North slope of Tazhong uplift. Correlation between oil and source rock shows that the Ordovician reservoir oil of Tazhong 45 well is derived mainly from Cambrian source rock. According to the occurrence and structural feature of CaF2, it can be inferred that the No.I fault activity maybe response for the generation of CaF2.Integrated with the result of oil-source correlation, and the occurrence of bitumen with different reflection ratio and different fluorescence, it can be deduced that perhaps there are three phase oil charging to the Ordovician reservoir of Tazhong 45 well: that is in the Early Ordovician, Permian and Cretaceous. And the oil yielded in the Permian from the source rock of Cambrian-Lower Ordovician in the west of Manjiaer Depression and in the North Slope of Tazhong Uplift is the dominant section of the current reservoir.
  • The research on the formation of Upper Triassic Xuer gas reservoirof Pingluoba gas field in Chuanxi depression
    LAN Daqiao and QIU Zongtian
    , 2002, 29(3): 453-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The Upper Triassic Xuer reservoir is the main reservoir of Pingluoba composite gas field. Tight reservoir sandstone has the typical characteristics of small pore and thin throat. Based on the relationship between the remained areal porosity of liquid hydrocarbon invasion and the chlorite, as well as the evolution of pore space and the depth of autogeny quartz formation, the reservoir sandstone had the evidence of earlier inputting oil and more original intergranular pore (more than 11% areal porosity) when hydrocarbon migrated. The invasion of liquid hydrocarbon changed the palaeo physical and chemical environments, the numerous secondary pores were produced and the settling SiO2 filled the original intergranular pores. From the historical research of sedimentary and structure in this area, it was recognized that Pingluoba structure was initially formed and the source rock reached low mature at the end of early Jurassic, mature at middle Jurassic, the same time of the accumulation as the hydrocarbon generation. The structure was later continuously upfolded, the structural closure enlarged, and hydrocarbon accumulation space increased. Multiple period fracture systems were formed which not only enlarged the reservoir space, but also connected the source rock and reservoir as well as the inner reservoir. The fracture system led the continuously generating hydrocarbons migrate to the closure and the gas reservoir possess good connection and consistent pressure gradient. High gas production from high fracture rate of high position of the structure shows the gas reservoir was controlled both by the fractures and the structural trap. The keys on the formation of Pingluoba Xuer gas reservoir are the early upfold of the structure, high porosity and permeability before the reservoir tight, rich gas source, fair composition of reservoir and seal and the same time of generation and accumulation of hydrocarbons.
  • Evaluation of the hydrocarbon-generation potential for the Kongdian Formation of Palaeocene in Jiyang depression
    CHEN Jianyu; PENG Xiaobo; ZHANG Dongmei; FENG Guang; YANG Zherong; YOU Xingyou and GAO Weiyi
    , 2002, 29(3): 464-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The hydrocarbon-generating potential of Kongdian Formation (Ek), in particular, its second Member (Ek2) is a key of the breakthrough in the petroleum exploration at great depth of the Jiyang basin. The Huiming depression is the Ek sinking center with big thickness as high as 4000-5000m. The Ek2 has extensive distribution and dark mudstone of shallow lake-swamp depositional facies. It can be expected the deposition of deep lake exists in the center of the depression. It’s obvious that Huiming depression is the sinking center and would be best prospect of the Kongdian Formation in the Jiyang basin. According to few analytical data of geochemistry, the source rock (SR) of the Ek2 has fair organic richness and type Ⅲ organic matter with high maturity and can generate light oil and gas. The Ek2 SR in Wuhaozhuang depression in eastern Jiyang basin has fair organic richness and type Ⅱ organic matter with high maturity and can generate light oil. The south part of Huanghua depression and the Weibei depression have Ek2 SR, and produce oil and gas. The Ek2 SR in the Huiming depression is similar with that in the Weibei depression, and the Ek2 SR in the Wuhaozhuang depression is similar with that in the south part of Huanghua depression. It’s much possible to form the self-original, closed petroleum system with Ek2 SR, reservoir sandstone and cap-rock thick mudstone in Ek1 in the Jiyang basin.
  • Characteristics and maturity of crude oil in Yitong graben
    LIU Hongyou; PENG Suping; WEI Zhiping and ZHAO Zhanyin
    , 2002, 29(3): 465-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    In this paper, the authors discussed the features of the crude oil in Yitong graben by the analysis of bulk composition, carbon isotope and maturity. There is higher wax content in the crude oil. The δ13C of the crude oil is between -26‰ and -29‰, which shows the heavier carbon isotope characteristics, which is thought to be the lower mature oil. The geochemistry study shows that the crude oil feature is related to special parent matters of Yitong garben. At present, the found crude oil are all mature oil, not low mature oil. There are also some high mature oil, the maturity of crude oil is gradually increasing from Moliqing rift to Luxiang rift, and then to Chaluhe rift. Study also shows that those source rock maturity and migration conditions are the controlling factors to oil and gas distribution.
  • An approach to the composite petroleum systems of Es14 in Bonan sag, Shengli oil province
    WU Fuqiang; LI Houshu; HU Xue; LIU Jiaduo and SUN Xiwen
    , 2002, 29(3): 488-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    It has been confirmed that the composite petroleum systems of the upper part of the Shasi member in Bonan subsag exist as result of multisets of hydrocarbon resources and the complicated structures etc. The elements and processes of petroleum systems have been respectively researched. It has been discussed that the petroleum system generally depends on the crust-mantle construction. The targets of hydrocarbon exploration and research significances have been pointed out.
  • Triassic sequence stratigraphy in Kuqa foreland basin
    HE Hong; GUO Jianhua; PENG Suping; WU Dongsheng and GAO Yunfeng
    , 2002, 29(3): 489-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    A systematic study on Triassic sequence stratigraphy in Kuqa foreland basin has been carried out by integration of seismic, logging and drilling data and outcrop survey. 13 sequences' boundaries have been identified, and they were divided into 12 sequences and 33 system tracts. Two different models of sequence stratigraphic framework were established through studying the internal composition of sequence strata and boundary of individual sequences. From early Triassic to the end of Huangshanjie stage of late Triassic, this basin appeared as a strong compressive piedmont alluvial-hungry basin, a typical foreland basin. The model of the sequence stratigraphic framework and its internal composition are similar to that of Vail's passive continental marginal basin, respectively. In contrast, from Taliqike stage of late Triassic to the end of Cretaceous, the basin shows smooth and expansive features, and has a unique model of sequence stratigraphy framework and its special internal stratigraphic composition. The evolution of sequences was mainly controlled by regional tectonic activities, paleoclimate and sediment supplies. The main factors controlling the changes of lake or base-level are orogenic episodes of the tectonic activities. The period for the lake to be deepened as a result of strong orogeny is the major period of lake transgression whilst the stage of the relatively weak orogeny is the major period of lake degression. The changes of climate mainly impacted on sedimentary facies within sequence frameworks.
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