, Volume 31 Issue 5
    

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    石油地质研究
  • Advances in studies of petroliferous structures and tectonics
    HE Dengfa; JIA Chengzao; TONG Xiaoguang and LI Desheng
    , 2004, 31(5): 902-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The petroliferous structural geology and tectonics investigate the controlling of structures and tectonics on sedimentation as well as formation and distribution of oil and gas pools or fields. International academe of petroleum geology placed strong emphasis on structural research of petroliferous basin and region. The methodology of petroliferous structural geology is mainly based on the process of description to understanding, then to prediction. With the breakthrough of the theory of structural geology, the improvement of experiment methods, and especially of the geophysical exploration techni-ques, the petroliferous structural geology is pushed forward rapidly, and the description of structures, understanding of the origins and mechanism, and prediction of distribution are improved. The great progress of the theory, methods and techniques, and effectual application are reviewed: ① the geodynamic model of the petroliferous basin; ② configuration, origin and distribution of the structural belts in the basins; ③ theory, techniques and method of structural analysis; and ④ control rules of structures and tectonics over petroleum.
  • Three-dimensional physical experiments of symmetrical fold
    SHAN Jiazeng
    , 2004, 31(5): 903-0.
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    On basis of the results from three-dimensional physical experiments of formation and evolution of fold,following knowledge is obtained: symmetrical fold may be formed under symmetrical compression stresses when direction of action stresses are perpendicular to boundary of deformational body with ductile and brittle-ductile material with the same layer thickness. The style of symmetrical fold spread over symmetrical model center along x-axis, but structural deformation of fold is characterized by nonuniform along x, y and z axis. The angle between axis of fold and loaded boundary is about 30°, this character is closely related to nonhomogeneous gliding of bedding and nonuniform displacement of material particle. The structural deformation is different in shallow and deep layer. Ramp fold-thrust may be developed on bottom of model. Core thickness of fold is larger than flank thickness of fold. Length of model shortened 27% than initial length in the end of experiment. Thickness of fold highest point in the model thickened 36% than initial thickness. The stresses propagate from loaded boundary to unloaded stresses boundary under unidirectional compress stresses. Fold may be formed by action and reaction force, but deformation is obviously near loaded boundary. Fold-thrust developed on the bottom of the model with uniform of stress propagation direction. Buckling of layer is characterized by low-angle to high-angle with increase of depth in the experiment.
  • Organic carbon isotope record in marine sediment and its environmental significance—An example from Ordos Basin, NW China
    Tengger; LIU Wenhui; XU Yongchang and CHEN Jianfa
    , 2004, 31(5): 904-0.
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    Marine sedimentary organic matter degradation and carbon isotopic equilibrium are obviously influenced by anoxic environment. The organic matter in the Kelimoli Formation of Zhuozishan Section, Ordos Basin, NW China, is standard sapropel with δ13Ｃorg value of －30.0‰ - －28.1‰ and the δ13Ｃorg value decrease from bottom to top, suggesting an anoxic environment and microbial alteration. Additionally, higher planktonic productivity, higher total organic carbon content (averaging 0.31%), better preservation conditions and higher hydrocarbon generation potential suggest potential efficient hydrocarbon source rocks. The organic matter in the Majiagou Formation of Qishan section is standard humus with heavy δ13Corg value of －25.7‰ - －24.1‰, which suggests close relation to the same term layers on Zhuozishan Section. The values correlate with benthic algae colonization and oxic environment. The δ13Corg recorded the types of organic matter, the changes of ecological and sedimentary environments, that could be regarded as an effective tool for reconstructing paleo-environmental from sedimentary organic matter, and further investigating marine hydrocarbon source rocks.
  • Distribution of nitrogen compounds and migration of the oils in the Xifeng Oilfield, Ordos Basin, NW China
    DUAN Yi; ZHANG Hui; WU Baoxiang; ZHENG Chaoyang and WANG Chuanyuan
    , 2004, 31(5): 905-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The Xifeng Oilfield is the largest new-discovered one in the Ordos Basin, NW China. Distribution of the nitrogen compounds in crude oils of the oilfield shows that the migration fractionation of neutral nitrogen compounds in the crude oils are present in the lateral and vertical directions of the oilfield. However, the small variance in the absolute concentration and isomer parameter values of neutral nitrogen compounds in oils from the subsection of Chang-8 oil layer of the Yanchang Formation indicates the short migration distance of the oils. The migration fractionation features of neutral nitrogen compounds in the oils show that the charging direction of crude oil is mainly from the northeast of the oilfield to the southwest and partially from the south to the north for oils from the subsection of the Chang-8 of the Yanchang Formation. It is also observed by means of the migration fractionation of neutral nitrogen compounds in the oils that vertical migration direction of crude oil is downward for Chang-8 oil leg and upward for Chang-3 oil leg and Yan-8 oil leg. This oil migration direction of Xifeng Oilfield is consistent with the distribution of subsurface fluid pressure of the studied area. These oil migration pathways suggest that the oils of Xifeng Oilfield are mainly derived from the subsection of Chang-7 of the Yanchang Formation.
  • Igneous lithofacies in Zao 35 Block, Dagang Oilfield
    WANG Huachong; RAN Qiquan and HU Yongle
    , 2004, 31(5): 906-0.
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    Based on lithology characteristics and distribution of igneous rocks in the Zao 35 Block of Dagang Oilfield, the lithofacies mode of igneous rocks is established. Based on the mode,the igneous rocks are divided into two lithofacies (outburst and overflow facies) and four microfacies (tuff, volcanic breccia, vesicular basalt, and dense basalt microfacies). The profile and plane distribution characteristics of microfacies are described. The attempt is made on calibrating igneous lithofacies with seismic attribute. The domination of igneous microfacies on the types of reservoir space and degrees of fracture growth are also studied.
  • Development periods of fractures in the Late Triassic-Jurassic in the north Chuxiong Basin
    LAI Shenghua; YU Qian; ZHOU Wen and SUN Laixi
    , 2004, 31(5): 907-0.
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    The development periods and control factors of fractures in the Late Triassic—Jurassic in the north Chuxiong Basin were determined by using the outcrop description, stable isotope and inclusion thermometric analysis and ESR of fracture fillings, theacoustic emission of oriented specimen and the rock mechanics property survey. About 5 stages of fracture development have been identified as early Yanshan Period, in which the fracture fillings homogeneous temperature of inclusions was about 95℃; late Yanshan Period, the homogeneous temperature being 110-130℃; and the 3rd, 4th, and 5th fractures were developed in early, middle and late Himalayan Period, respectively, and the homogeneous temperatures were about 146℃, 173℃ and 220℃, respectively. The fracture development has been controlled by 2 factors: ① the structure deformation degree was determined by tectonic stress intensity. Generally, the more deformities, the more tectonic fractures were developed.② the mechanical property of rock, the distribution of rigid rock and the thickness stratum are important. The formations have more fractures as petrological density and tensile strength decrease and porosity increase. The thinner the formation, the more are the fractures, conforming to a certain power function.
  • Sequence stratigraphic framework and sedimentary types in the Block 5 and 6, Bonan Oilfield
    WU Fadong; CHEN Yongjin; HUANG Gaojian and CHEN Jianyu
    , 2004, 31(5): 908-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The sequence stratigraphy and sedimentary system analysis suggest that the Bonan sub-sag could be subdivided into 2 tectonic sequences and 7 third rank sequences. The sub-sag was an asymmetry Tertiary fault-step basin, south of which was slow fault-step belts and are mainly delta plains and delta front sediments. But in the north part of the sub-sag, controlled by the syn-sedimentary fault, steep fault-step was developed with mainly deposition of sub-aqueous fan, turbidity fan, and front of fan-delta. The sandstone groups No.0-9 were developed from the uplift in the SE direction and the sandstone groups No.0-8 were developed in the fan-delta environment, suggesting a main process of lacustrine filling up and prorogation.
  • Anomalous body and reservoir evaluation of the strata of Middle-Upper Ordovician in the Shunxi Block of Tazhong Area, Tarim Basin
    ZHU Junling; ZHANG Jiteng; JIAO Cunli; WANG Yahong; ZHOU Changjun and XIE Chen
    , 2004, 31(5): 909-0.
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    Shunxi Block is located in the northwest slope of Tazhong Uplift. Many geologic anomalous bodies are developedin the Middle-Upper Ordovician System and can be divided into mound, lens and wedge bodies according to their shapes. The study of paleogeology and drilling data suggests that Tazhong Area has the conditions of growing reefs and submarine turbidity sediment. Combined with the study of their geophysics characters, the anomalous bodies are considered to be reefs, calcilutite mounds, lime-mud lumps or canal-filling lenses, in which the traps formed from reefs or moulds are of better combination of source rock, reservoir and cap rock, and are favorable play targets. As long as the breakthrough is made, the anomalous body traps will be the new significant exploration areas of oil and gas in Tazhong Area, Tarim Basin.
  • Carbonate reservoir of the Oligocene Member 1, Shahejie Formation, Dongxin Oilfield
    WANG Hongbao; WANG Shubao; LI Yong; ZHONG Jianhua and WANG Xibin
    , 2004, 31(5): 910-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The lacustrine carbonate rock in Member 1 of Shahejie Formation, Dongxin Oilfield, composes mainly of biolithite and ooides limestone as well as a few ancylus fluviatilis limestone, and is developed in a real favorable position for oil and gas migration and accumulation with great resources potential. The geological proven information could be achieved for the exploitation according to the lithologic characters, logging and inner-micro-structure, for which the deposit and diagenesis and the reservoir characters could be identified. The biolithite made up of stratums with biology fragment and fossils have admirable pervasion ability, in which dissolved pore, organism pore and framework pore play important roles in preserving oil and gas. Ooides deposit in shallow and high energy environment, and are mainly fragment ooides, loop ooides and remnant ooides, so the cores are more biogenic debris than calcite crystal, and the reservoir is of excellent quality. The Member 1 of Shahejie Formation has experienced the processes of cementation, dissolution and dolomitization.
  • Control of Late Carboniferous-Early Permian sea level fluctuation on coal reservoir heterogeneity, Taiyuan, Shanxi
    JIN Zhenkui; ZHANG Xiangxiang; ZHAO Kuanzhi; LIU Ronghui and WANG Chunsheng
    , 2004, 31(5): 911-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Sea level fluctuation can control both the types of sedimentary environments and types and scales of swamps. Sea level fluctuation is closely related with abundance of coal, coal thickness, coal lateral stability, coal composition, coal ash production rate, coal gangue distribution, etc. As these parameters can influence porosity and permeability of coal beds, sea level fluctuation directly or indirectly controls porosity development and heterogeneity of coal beds. The study on coals of the upper Carboniferous and Lower Permian in Taiyuan, Shanxi Province, shows that during rapid rise of sea level (transgressive system tract), the coal beds formed are few and thin. They are mostly lenticular in shape and unstable laterally, and thus their lateral heterogeneity is strong. But their gangue beds are less, ash production rate is low, and intrabed heterogeneity is weak. During relative fall of sea level (high-stand system tract), the coal beds formed are many and thick, which are mostly sheet-shaped and stable laterally, and thus their lateral heterogeneity is weak. But their gangue beds are many, ash production rate is high, and intrabed heterogeneity is strong. In interbedded marine-nonmarine strata, frequent fluctuation of sea level results in frequent change of coal bed characteristics, and thus interbed heterogeneity is strong.
    • 综合勘探开发技术
  • Application of sequence stratigraphy in lithological reservoir exploration of the Upper Guantao Formation, Chendong-Feiyantan Oilfield
    ZHANG Benqi; JIANG Zaixing; XIA Bin; DONG Guineng; YANG Xiaobing; JIANG Benyong and HAO Qingfeng
    , 2004, 31(5): 912-0.
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    Distribution of reservoir in the Upper Guantao Formation of Neogene in Chengdong-Feiyantan Oilfield, Jiyang Depression is comprehensively studied by sequence stratigraphy and the high-resolution sequence stratigraphic framework is established. The Upper Guantao Formation can be divided into one 3-order sequence with 3 system tracts, 10 parasequence sets and 23 parasequences. Effects of the sequence boundary, max flooding surface, first flooding surface and parasequence boundary on oil distribution are demonstrated. Though sand-bodies occur mainly in LST and TST, the hydrocarbon is mainly distributed in TST.
  • Palaeo-geomorphology analysis for the Paleogene reservoir prediction in Bohai Sea area
    XU Changgui; LAI Weicheng; XUE Yongan; YU Shui and CHENG Jianchun
    , 2004, 31(5): 913-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The Bohai Sea area is one of the main hydrocarbon enrichment areas in Bohai Bay Basin. The exploration in Eeogene is greatly successful in recent years, but the exploration in Paleogene has not achieved a great breakthrough yet. For the Paleogene, the palaeo-geomorphology as a background of the sequence development controls both the sequence development and the genesis and distribution of the depositional system, for which the palaeo-geomorphology analysis could be a key and base for the middle-deep reservoir prediction. The basic characteristics of palaeo-channel and palaeo-tectonic slope break and its control on depositional system in Bohai Sea Area are studied and the reservoir prediction of two blocks in the area is taken an example to delineate the application of the palaeo-channel and palaeo-tectonic slope break principle for reservoir prediction of Paleogene in detail.
  • Prediction of low-resistivity zones in Sha-3 Member of the Q50 fault block based on logging-facies analysis
    LI Hao; LIU Shuanglian; ZHENG Kuanbing and LIU Zhi-rong
    , 2004, 31(5): 914-0.
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    The Q50 Block is a block rich in petroleum located in the east of the South Dagang structure in the Dagang Oilfield. The lithologic oil pools with low-resistivity are developed in the Sha-3 pay zone, which can be subdivided into 5 sandstone units. Their sedimentary characteristics could be clearly reflected by logging curves. The low-resistivity oil zones, which formed of high irreducible water saturation, exist in the edge of the bar with weak and unstable water dynamics and have thin interbedded lithologic structure and dual-pore system. However, the high resistivity oil zones mostly formed in the host bar with simple lithologic and pore structure. The distribution of low-resistivity oil zones could be predicted by exact cognition of sedimentary micro-facies. This method is applied to analyze 3 dry layers with high shale content and low resistivity in the Well Qi 50-10, and the amount of oil and gas is significantly enhanced by the formation testing, suggesting that the logging-facies analysis would be important for exploiting some developed oil fields.
  • Origin and identification of low resistivity oil layers in Wangji Oilfield, Biyang Sag
    ZHANG Xiaoli and WANG Kai
    , 2004, 31(5): 915-0.
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    The major controlling factors of petroleum accumulation in Wangji Oilfield are tectonic, fault, micro-facies and formation water. Well log response of the reservoir is complex. There are normal resistivity oil layer, low resistivityoil layer and high resistivity water-bearing layer, and their well logging curves are similar. Based on the characters, causes and distributions of low or high resistivity reservoir, the oil layer could be identified, suggesting that main causes of low resistivity oil layers are the high bound water saturation and the correlation between oil and water layer resistivity has been changed; the multivariate discriminate analysis method and equivalent elastic modules difference ratio method are effectively applied to identify low resistivity oil layer.
  • Oil saturation interpretation model of clastic reservoir from the formation conditions of reservoir fluid saturation
    ZHANG Fengmin; SUN Guangbo; YU Junwen and CAO Hongtao
    , 2004, 31(5): 916-0.
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    The multitudinous parameters in the Waxman-Smits as well as dual-water model, commonly used in the oil saturation evaluation of low resistivity lithologic reservoirs, can not be quantified because of the environment restrictions on the electric logging. The capillary pressure theory suggests that the impact factors of oil saturation are column height, oil and water density contrast as well as petrophysical property information from the formation conditions of fluid saturation. The oil saturation interpretation model of clastic reservoir is established based on the forming conditions of reservoir fluid saturation using oil column height, oil and water density contrast as well as petrophysical property information. The practice proves that the model is applicable both in the oil saturation calculation of low resistivity lithologic reservoirs and non-low resistivity clastic reservoirs
  • Prediction of reservoir sensitivity with well logging data in Dagang Oilfield
    ZHANG Zhencheng; SUN Jianmeng; LIU Zhiyun; HAN Cheng; SU Yuanda; ZHANG Wei and ZHANG Zhiyong
    , 2004, 31(5): 917-0.
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    The clay mineral type and content could have a strong effect on the reservoir sensitivity. The first thing for using the logging data to predict reservoir sensitivity should be to process the basic logging data by comprehensive methods and to establish reservoir sensitivity parameter model. According to the cases in Dagang Oilfield, the natural γ spectroscopy is used to identify the type and content of clays and other parameters are gotten by regression. The relationship between parameters and five-sensitivities is gotten by single-regression analysis. The method is testified and an efficient result is obtained in Dagang Oilfield.
  • Application of SVD filtering in the processing of decaying direct wave and refracted wave
    LI Wenjie; WEI Xiucheng; LIU Yang; WU Changjiang and ZHANG Chaofeng
    , 2004, 31(5): 919-0.
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    In the processing of seismic data, the quality of the processed seismic data can be improved if the influence of disturbed waves with strong energy in the crude data such as direct-wave and refracted-wave could be eliminated. The common cutting method would lose the information reflecting shallow geologic structure since that the reflected waves from the shallow layers are cut down together with the disturb waves. The SVD filtering method will be able to suppress the direct-wave and refracted-wave with linear characteristics and to strengthen the primary shallow seismic reflection energy with non-linear characteristics, and the useful shallow seismic reflection information would not be lost. The results of theoretical model and actual data processing suggest that the method is practically efficient.
  • High-power surface-borehole electrical method in predicting reservoir boundary and its application
    HE Zhanxiang; LIU Xuejun; QIU Weiting and HUANG Zhou
    , 2004, 31(5): 920-0.
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    High-power surface-borehole electrical method can be used for mapping spatial distribution and extent of known reservoir. The technology employs highly-powered electrodes emplaced in coiled tubing, in which the electrodes are powerd above and under studied reservoir, respectively, and two times of elecmagnetic response are recorded on ground. The difference calculation and analysis of the recorded data have been processed to obtain the resistivity distribution and polarization phase difference of hydrocabon-bearing layer. The boundary of target hydrocarbon-bearing layers and oil-bearing features of adjacent trap could be mapped based on the anomalies of foregoing two parameters. The method are used in the well field Q1, fore-land of West China, and in the well field H19, an oilfield in East China, where the predictions are fully confirmed by exploratory wells.
  • Calculation of the economic recoverable reserves in the undeveloped area
    RAN Qiyou; HU Xiangyang; ZHAO Qingfei; FANG Kaipu; CHENG Shiming and ZHAO Xiaojun
    , 2004, 31(5): 921-0.
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    A new calculation model is provided to calculate the economic limit of infilling in undeveloped area and to quickly evaluate the reserves. Based on the relationship between geology conditions, oil price, costs and investments, profit and loss balance theory and the exponential relation between recovery and well pattern density, a new model is put forward to determine the economic limit for well pattern infilling by calculation of the enhanced recoverable reserves a newly drilled well must provide. Applications demonstrate that the parameters of the new model are easy to derive and the calculation is convenient. It is a practical calculation method, satisfying not only fore-evaluation of adjusting drilling, but also evaluation of the reserves of undeveloped area.
  • Reserves asset method for Zhongyuan Oilfield
    ZHANG Tao
    , 2004, 31(5): 922-0.
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    Asset management mode of petroleum enterprises is changing from material object magnitude pattern to value magnitude management. In order to provide the method of evaluating the economic value of remaining recoverable reserves for Zhongyuan Oilfield, the relative pricing method is used to evaluate the economic values of remaining recoverable reserves in different kind of reservoirs and development units. With the marginal production cost of oil and gas, the development planning has been designed and the decision-making basis has been provided for realizing business administration of oil production in the oilfield, in which the asset management is the main management pattern.
  • Potential oil/gas-bearing segments in wells by the Peculiar State Mineral Method in the North Qaidam Basin, NW China
    GAN Guiyuan; KONG Hongxi; YU Ruijuan; LI Jiangtao; CUI Jun and LEI Zhenfeng
    , 2004, 31(5): 923-0.
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    The peculiar state mineral, the peculiar state mineral method and the peculiar state mineral index are explained, and four types of application of the Peculiar State Mineral Method for petroleum exploration are summarized. Three types of peculiar state mineral indexes in the North Qaidam Basin are classified, including ClassⅠ, indicating more than 10 m3/d oil or huge gas produced; ClassⅡ, indicating several cubic meters of oil flowing; and Class Ⅲ, indicating a little oil produced, or oil/gas show. By using the Peculiar State Mineral Method, several advantageous exploration well segments in some wells have been predicted or evaluated, including re-evaluating the potential oil/gas-bearing segments in the Well Xian 3, Xian 6 and Well Xian 9 with commercial oil and gas flowing, predicting oil/gas-bearing intervals in the Well EⅠ2 and Lengqi 2, and two important oil/gas-bearing intervals in the Well Shen 85 in which one was proved by oil test.
    • 油田开发与油藏工程
  • Discussions on developing hydrophilic sandstone reservoir by water injection-production
    WANG Heqiang; CHEN Zhiyu; ZHANG Lihui; LI Xiaoliang; XIA Guochao; ZHANG Jialiang; WANG Qingkui; WANG Xuecai and ZHANG Jing
    , 2004, 31(5): 924-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Most reservoirs of the south Dagang Oilfield are complex fault block pools with faults developed in the reservoir. The blocks are small and closed, the reservoir permeability is low and oil viscosity is high, which makes it difficult to displace oil by water flooding. Soon after injectors are brought into production, the injection pressure is increased rapidly. Meanwhile, the injectivity decreases dramatically, which leads to little benefit to corresponding oil wells. For this kind of reservoir, hydrophilic property of the sandstone could be used advantageously. According to the spontaneous imbibition expulsion mechanism of the sandstone, the higher recovery efficiency could be obtained by water injection-production. Wang 26-1 block of Wangguantun Oilfield is of low permeability, and Zi 19-14 block of Zilaitun Oilfield is of high viscosity, and both are hydrophilic complex block pools. On the success of pilot test, the development mode of water injection-production had been used in this way and oil production increment of the two blocks reached over 22,000 t.
  • Enhancing oil recovery of edge and bottom water reservoirs in the small fault blocks by using special wells
    TANG Jiandong
    , 2004, 31(5): 925-0.
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    The Anfeng and Songjiaduo Oilfield in the Jiangsu Oilfield consists of small complex fault block reservoirs with edge and bottom water, and the reservoirs are characterized by small reserve volume, narrow oil bearing area, rapid water-cutrise, many closed wells and high cost. The remaining oil mainly locates in the top of the structure along the trace of fault which is not controlled completely by well pattern, zone among wells, zone sheltered by interlayers. The development efficiency is improved by tapping the remaining oil with special wells such as side tracked wells, horizontal wells, and high accuracy directional wells with multi-targets. The cost for 19 common wells could have the effect of 34 wells and the marginal reservoirs are developed efficiently.
  • Development of volatile gas pool in the Kekeya Condensate Gas Field
    WANG Xinyu; MU Weijun; DING Guofa; LU Ke-feng and Lü Jiangyi
    , 2004, 31(5): 926-0.
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    The X52 gas pool in the Kekeya Gas Condensate Field, Xinjiang Province, is the first volatile gas pool developed in China. Because of the special reservoir fluid, heavy heterogeneity of reservoir and early uncontrolled well blowout in 1977-1982, water coned into the initial oil zone in which the distribution of fluid became complicated and the initial reservoir pressures and fluid samples are not achieved. The early development scenarios had been compiled based on initial pressure, temperature, fluid contacts, and fluid behavior restored from the lab test results of oil samples gotten after development. The early development plans were rigorously carried out with fine reservoir description, horizontal well infilling and gas lifting of shut-in wells in the late period of development. Fifteen years of production demonstrated the favorable development efficiency. The ultimate oil recovery is also predicted to be over 30% at current operating conditions.
  • A new approach to study layered producing performance of oil and water wells
    DU Qinglong and ZHU Lihong
    , 2004, 31(5): 927-0.
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    It is difficult to accurately analyze the performance of a multi-layered sandstone reservoir because zonal testing data of producers and injectors are not adequate. A new practical approach to study the layered producing performance of oil/water wells is presented to solve the problem. Based on the balanced flood within well groups, the approach taking into account pay zone parameters (such as thickness, permeability and viscosity) of the injectors and their corresponding producers, and the producing conditions including the producer-injector spacing, producing pressure drop and well stimulations, and distributing the water injection rate to each layer with areal and vertical distribution coefficient, then the layered fluid production rate is calculated. The result obtained by this approach match well with the actual data.
  • Abnormal productivity equation of condensate reservoir
    LIU Liming; JING Xiangwei; LI Yongyong and LIAO Xinwei
    , 2004, 31(5): 928-0.
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    Productivity equation based on traditional reservoir engineering method sometimes leads to negative slope, which is meaningless for the testing data of condensate well with low permeability, high temperature and very high pressure. And the pseudo-condensate pressure method remains to be inapplicable because of the difficulty to acquire the relative permeability data. Based on engineering demand and basic productivity equations, two methods to derive the binomial productivity equations are put forward by analyzing the separation of oil and gas, the equation of state and the integral of relative permeabilities: split gas pseudo-pressure (SGPP) method and typical regional relative permeability pseudo-pressure (TRRPPP) method. These pseudo-pressures make the productivity equation very applicable for condensate reservoir. The methods are used to interpret the well testing data of the Well KS101 in Kekeya gas field, Tarim Basin. The results present a high consistency with the daily performance of the well.
    • 油田非注水开发
  • Long core physical simulation for CO2 miscible displacement
    LI Xiangliang; LI Zhenquan; GUO Ping; LI Huanchen and LI Xuesong
    , 2004, 31(5): 929-0.
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    In order to optimize the technological parameters during injection gas for CO2 miscible displacement, a pilot in Shengli Oilfield, the displacement characteristics and sweep efficiency for CO2 miscible displacement are investigated under the conditions of 30 MPa and 116℃, and the influence of the injection opportunity, injection mode and injection volume on the miscible sweep efficiency are also studied. The experiment results proved that CO2 can be miscible with reservoir oil of Fan 124 fault block at 30 MPa, and enhanced recovery is above 16% at present reservoir conditions. The influence of the injection opportunity and mode of CO2 injection on the effect of the miscible displacement isn't obvious in homogeneous long core model test, however the early injection can extend water-free production period and improve the oil production rate, and WAG injection can effectively control gas breakthrough caused by the formation inhomogeneity, suggesting early WAG injection is better, and CO2 injection volume should be above 0.25PV.
  • Flow performance of viscoelastic polymer solution in dead end of reservoir pores
    ZHANG Lijuan; YUE Xiangan; REN Guoyou and LIU Zhongchun
    , 2004, 31(5): 930-0.
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    The upper-convected Maxwell model was used to describe the rheological property of polymer, and the flow behavior of viscoelastic polymer solution in dead end of reservoir pores was simulated numerically. At low Reynolds numbers, the varying laws of velocity field, stress field and pressure field with inclination angle of dead end and the viscoelastic property of fluid were theoretically studied,suggesting that the greater the viscoelasticity of fluid, the greater is the velocity and stress in the dead end and the more obvious is the pressure fluctuation. The pressure surging region is related to deformation ability of fluid, and the elastic deformation mainly occurs where pore intersects dead end.
    • 油藏物理
  • Phase behavior and flow of sour gas under reservoir conditions
    ZHONG Taixian; YUAN Shiyi; ZHOU Longjun; LI Haiping; YANG Weizong and LUO Kai
    , 2004, 31(5): 931-0.
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    Much sour gas reservoirs with high H2S content have been discovered in East Sichuan Basin recently. The existence of elemental sulfur is controlled by the formation pressure, temperature and gas composition. During the development process, the relative lower near well-bore pressure and high gas flow will directly change gas flow state, thus further induce sulfur precipitation. The precipitation in the porous flow will block the gas flow and more deposition occurs in the well-bore. These changes will have a negative effect on the well productivity. A thermodynamic model is developed for describing sulfur deposition law with the change of pressure and temperature. The sulfur deposition model is established under both Darcy and non-Darcy flow conditions.
    • 油层保护与改造
  • Low-density oil in water well-control fluid for buried hill gas condensate reservoir of Qianmiqiao Oilfield
    YANG Xizhu; ZHOU Fujian; ZHENG Shujie; WANG Lingmei; DAI Liyang and ZHONG Huimin
    , 2004, 31(5): 932-0.
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    The condensate gas reservoir of Qianmiqiao, Dagang Oilfield, is buried deeper than 4000m in a middle development phase. The density of the water base control fluid is over 1.0g/cm3, and fluid leakage always occurs during well cleanup, which seriously damage the reservoir and decrease the productivity. The pressure sensitivity, velocity sensitivity and damage of water invasion are analyzed and evaluated by laboratory study. The results show that under net pressure, the pressure sensitivity of the reservoir cores is strong, the velocity sensitivity is weak and the water invasion damage is middle to strong. Under the modeling conditions of high temperature, the control fluid damage of the reservoir is evaluated. The results show that the average permeability damage is 53% for the gas layers with permeability lower than 10mD. According to the damage mechanism, a low density oil in water control fluid with density of 0.84~0.9g/cm3, heat resistance of 168℃, water/oil pollution capacity of 10%, is proposed. The average permeability recovery is 90.06%, and the lowest is above 87.6%.
  • Vibration-mud acidization treatment broken down experiment
    ZHANG Rongjun and PU Chunsheng
    , 2004, 31(5): 933-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The zones nearby the well could be blocked by inorganic crust, organic crust, microorganism, foreign grain, and clay in the development of low permeability oil and gas fields. So the exploitation cost of the reservoir is always high. The vibration, mud acidization and vibration-mud acidization comprehensive experiments suggest that the comprehensive experiment should have higher efficiency than that of single way. The vibration broken down technique improves the core permeability by 10%-20%, the mud acid by 10%-40%, and about 40%-70% will be gotten by using the comprehensive technique. The fluid flow in the production and injection well is stimulated by the experiment. The results suggest that the effect of vibration-mud acidization treatment is better and more stable than that of other treatments.
  • Evaluation of injector damage in the Lunnan Oilfield, Tarim Basin
    ZHOU Lizhi; MA Hongying; FANG Ke and SHEN Jianxin
    , 2004, 31(5): 934-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Absorption efficiency (α) is defined as the ratio of actual injection rate (Qt) to theoretical injection rate (Qf) based on the reservoir damage characteristics of the injectors in Lunnan Oilfield, Tarim Basin. The damage degree can be classified according to the change of α with time (t): non-damage, minor damage, normal damage and severe damage. The curve (α-t) can reflect the reservoir damage of injectors at different time, and thus can be used to realize the change of injection water quality. The chart (Qt-Qf) can directly reflect the general damage of an injector in a long time. Compared with the normally used evaluation method, i.e, damage factor S which shows only the damage of an injector at some time and is very costly to gather related data to evaluate, the new methods of α-t and Qt-Qf are better as the reguired data can be gained easily, the analysis is efficient and the result can be easily understood, which are very convenient to monitor the damage of injectors and the injection water quality.
  • New model for fracturing fluid leakoff in naturally fractured gas fields and its application
    LI Yongming; GUO Jianchun; ZHAO Jin-zhou; WU Xiaoqing and LI Ya
    , 2004, 31(5): 935-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Fracturing of wells in naturally fractured gas fields can differ dramatically from fracturing wells in conventional isotropic formations. Fluid leakoff is the primary difference. A new model is set up for modeling fluid leakoff in naturally fractured gas fields, its exact solution is presented by means of orthogonal transformation and the effects of some parameters on fluid leakoff are studied. Based on large amount of calculation, a new equation is firstly presented to calculate fluid leakoff in naturally fractured gas fields, which can be simplified to the classic model. The new model can be used to instruct fracturing design and analysis of fracturing pressure. The mathematical model and its solution method can be extended to solve the problems of fluid leakoff in naturally fractured oil reservoirs or multi-medium reservoirs.
  • Mechanism and application of furfural resin sand consolidation agent modified by organic silicone
    ZHENG Yancheng; LI Kehua; ZHOU Ailian; WU Yunqiang and MA Xiaofeng
    , 2004, 31(5): 936-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Organic resins are easily broken up at high temperature, thus sand-consolidation agents made from normal resins can not be used in steam-injection production of heavy oil. So inorganic filler (HA) with high break-up temperature and furfural resin (HB) modified by organic silicane resin (HK) is used to consolidate sands in the production of heavy oil. Suitable component by optimal test is: 37.5%HA+25%HB+37.5%HK. Laboratory evaluation results show that the sand-consolidating cores have pressure-bearing strength of over 5MPa ,and high permeability of 0.5D at 300℃ after 148h. Field tests of 10 wells in Karamay oilfield indicate the sand-consolidating agent has good sand-consolidation ability in steam-injecting wells, and sand content of crude oil is little. Field tests also indicate that pretreatment to formation and addition of viscosity-reducing agents are helpful to sand consolidation and oil production.
    • 学术讨论
  • Some Considerations on the Silurian petroleum exploration in the Tarim Basin—Taking Tazhong region as an example
    SONG Jianguo and WU Zhen-quan
    , 2004, 31(5): 937-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Some queries on the ideas that a giant paleo-oil pool developed within the Silurian of Tazhong region, Tarim Basin, are presented. The widely distributed tar sands in the Tarim Basin could be the sign of oil and gas migration and is produced by the formation watering on the disperse hydrocarbon during the migration, which means the "giant Silurian paleo-oil pool" had never be developed yet. A new suggestion on the direction of Silurian petroleum exploration in the Tazhong region is proposed for search the refilled oil and gas pools in the tar sands distributed areas and then leap over these areas to seek the primary oil and gas pools towards the oil source direction. The proposals on the future research work especially the concrete conception for improving the research on the complicated petroleum system are also presented.
  • Discussions on FZI methodology in flow unit identification and discrimination
    JIN Yan-xin; LIN Chengyan; ZHAO Li and ZHAO Lijuan
    , 2004, 31(5): 938-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    As a variable related to rock porosity and effective hydraulic radius, FZI (flow zone index) is defined as the ratio of the Reservoir Quality Index to Normalized Porosity Index. Though it is widely used in flow unit identification and discrimination, FZI also has some problems in the definition. Detailed analysis of mechanism and procedure of the methodology indicates that the FZI is affected by the rock porosity and the relationship between the permeability and porosity derived from FZI is dubious. Uniform FZI can be gained if permeability and porosity magnify or minify certain times. The reservoir with a great difference in physical properties may have same FZI and the flow unit generated from this methodology doesn't coincide with its concept and can not achieve the object that the geological and petrophysical properties are internally consistent in the same flow unit and have predictably difference between different flow units. Therefore, the method is not recommended in flow unit discrimination.
  • The formation of the dense sandstone cap in the Well Yingnan 2, Tarim Basin
    YU Hezhong; ZHANG Lixia; HAN Shouhua; ZHU Guohua and SI Chunsong
    , 2004, 31(5): 939-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The data of the cores and the well-logs show the rocks above the main gas layers are all sandstone instead of argillite in the Well Yingnan 2. Based on the casting thin section observing and researches on the electricity, property of the cores, mercury-injection, SEM and clay mineral X-ray diffraction data, it is clearly discovered that two sets of dense sandstone in the Well Yingnan 2 could be the effective caps of the gas layers. The sandstone contains rich asunder argillaceous matrix (6.6%-13.8%), and it deposits in the surfaces of the grains and intergrains in net-like and envelope-like way. The strong water-lock effect could make permeability to decrease by more than 80%. Under the condition of water existence, the air permeability could decrease from 0.47-0.69 mD to lower than 0.1 mD, which is the key cause of the dense sandstone developing into an effective cap rock.
    • 国际交流与合作
  • Oil and gas source rock correlation in Malacca Strait Contract Area, Indonesia
    XI Fengyun; PAN Mao and ZHANG Guangya
    , 2004, 31(5): 940-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    After near 3 decades of exploitation, the remaining reserves of the oilfields in Malacca Strait Contract Area were running out. In order to get the information of the exploration potential of the Contract Area, detailed research on the oil and source rock correlation was carried out. Some effective correlation methods were applied in the research, such as carbon isotopic composition, component analysis and biomarker methods. Through the correlation, the source of the oil and gas was defined and considered to be isogenous, generating from the lacustrine facies dark mudstone of the Brown Shale Formation in the Bengkalis Sag.
  • Supplement to determining method of cut-off value of net pay
    GUO Rui
    , 2004, 31(5): 941-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Reservoir evaluation and OOIP estimation are based on the establishing of cutoff value of net pay. Although multiple methods are available, there is much uncertainty in determining the cutoff value due to limited testing data. The cutoff value of net pay depends greatly on the component texture, fluid property (especially, crude oil property) and buried depth. 64 cutoff values of net pay have been gained in overseas oilfields evaluation. The relationship between cutoff value and crude oil gravity or burial depth is gained according to the statistical analysis on overseas cutoff values of net pay. It could be used to determine and check the cutoff value of net pay in new oilfields.
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