, Volume 29 Issue 4
    

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    石油地质研究
  • My second discussion on network-like oil and gas pools and the exploration strategy for Lunnan buried-hill pools
    ZHOU Xingxi
    , 2002, 29(4): 213-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The external shape of the network-like pools looks like that of stratified or massive oil and gas pools, but actually, their petroleum accumulated in reservoir space system which is composed by pores and caves (solution pores and caves mainly) connected by faults and fractures. So, these pools are very heterogeneous. The Lunnan buried hill pool is located in the development region of network-like oil and gas pools. This development region can be divided into 5 oil and gas abundance zones based on the forming conditions of pools and the property characters of the hydrocarbon fluids, from where 5 oil and gas fields with a total OOIP of 500 to 800 million tons are prospectively discovered in the near future. Within the network-like pools or oil and gas aboundance zones, there maybe appear some stripper oil wells or even water wells or dry wells, but this dose not mean that the resources potential is negnigible and the exploration should be stopped. Due to these pools are easy to be damaged during drilling, a set of special technology should be adopted, such as near-balanced and under-balanced drilling, open-hole completion, maximumly preventing damage from well logging and testing, massive acidization and fracturing, in order to reach a high and stable oil production.
  • Unusual distribution and its origin of n-alkanes in extracts of marine carbonate rocks with high maturity and over maturity
    LI Jinggui
    , 2002, 29(4): 214-0.
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    Alkanes in extracts from carbonate rocks of the Lower Ordovician Majiagou Formation in the central gas field of the Ordos basin and the Upper Sinian Dengying Formation of Weiyuang gas field, Sichuan basin, are characterized by bimodal distribtion with the dominant carbon numbers of C17, C19, C20 or C21 in the first groups, and C25, C27 or C29 in the second groups. In most samples, the lower carbon number components are present in greater abundance than those in the higher carbon number range. Most samples contain significant concentrations of waxy hydrocarbon (C22+) with C21-/C22+ ratios between 0.50 to 2.75(one exception of 3.16), and an average value of 1.27; the n-alkanes in extracts of outcrops and shallow core samples of Upper Proterozoic and Lower Palaeozoic carbonate rocks in the western and southern parts of North China basin have unimodal distribution dominanted by n-alkanes maximizing in the C25～C29 range. These extracts have very high concentrations of waxy hydrocarbons with the C21-/C22+ ratios all <1.0, ranging from 0.14 to 0.90 and an average value of 0.36. All of the extracts have marked odd/even predominance in the high molecular weight n-alkane range regardless of whether they are from shallow or deep cores or outcrop samples. Simulation experiments were performed using typical sapropelic-type kerogens from the immature Sinian Lower Xiamalin Formation calcareous shales collected at Jixian, Hebei province, North China basin, and the contemporary microplanktonic blue-green algae Spirulina subsala. Results indicate that the unusual distributions of n-alkanes in the extracts of Upper Proterozoic and Lower Palaeozoic carbonate rocks possibly originate from algae in highmature and overmature source rocks.
  • Geochronology of hydrocarbon accumulation in the Tarim basin: evidence from fluid inclusion
    ZHAO Jing-zhou
    , 2002, 29(4): 215-0.
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    Based on the analyses of hydrocarbon fluid inclusions from the main hydrocarbon-bearing reservoirs, geochronology of hydrocarbon accumulation in the Tarim basin has been comprehensively studied and discussed. 3 accumulation periods are discerned in Kuche forland basin (or Kuche Petroleum System), i.e. the early-middle Kangcun period (17-10Ma ago), late Kangcun to early-middle Kuche period(10-3Ma ago) and late Kuche to Xiyu period (3-1Ma ago). The early-middle Kangcun period is characterized by accumulation of oil and coal-derived gas of low or low-mid maturity, whereas late Kangcun to early-middle Kuche period by that of middle-high mature condensate, both of which are the major accumulation period of the Luntai uplift. The late Kuche to Xiyu is, however, a period for accumulation of high- to over-mature gas and the major forming time for gas fields in the Kuche forland thrust belts. Hydrocarbon fluid inclusions from the Tarim's craton area can be divided into 2-3 periods including late Hercynian, Yanshanian(Jurassic to Cretaceous) and Himalayan (Cenozoic), representing 3 period of marine hydrocarbon accumulations. The remained Paleozoic oilfields are mainly formed during late Hercynian, whereas the Mesozoic oilfields like Lunnan Triassic oil accumulations and some Paleozoic oil reservoirs such as CI and CII ones of the Tazhong 4 and Hade 4 oil fields are commonly secondary ones formed by adjusment of earlier formed primary oil accumulations during the late Himalayan (Neogene). Oil accumulations of late Caletonian to early Hercynian have been found nearly everywhere in the craton but were mostly destructed after the early Hercynian orogeny in the late Devonian.
  • Organic petrology of the source rocks in Qijia-Gulong region, Songliao basin
    MA Anlai; LI Xianqing; XIONG Bo; WANG TieGuang; FENG Zihui; KONG Qingyun and LI Shaohua
    , 2002, 29(4): 216-0.
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    Using whole rock analysis of organic petrology, a detail study on the maceral composition, hydrocarbon-generating maceral and thermal evolution of the source rock of Cretaceous Nenjiang Formation in Qijia-Gulong region, Songliao basin is carried out. The maceral content ranges from 0.7% to 15.8% by volume and with an average of 4.1%. There is great difference in maceral composition among the source rocks of different ages. The source rocks in Kn2 to Kn5 is lack of inertinite, but rich in vitrinite and relatively rich in exinite, showing high plant input domination. The source rock in Kn1, comparatively rich in sapropelinite, showing a mixture input of algae and high plant input, is the main source rock. Alginite is the main hydrocarbon-generating macerals for the low mature oil. Using vitrinite reflectance and the fluorescence parameters of sporinite, the thermal evolution of source is divided into unmature and low mature stage. The boundary corresponds to the 0.5% vitrinite reflectance, 2.2 relative fluorescence intensity I546 of sporinite and 1050m in depth.
  • Formation and evolution of Triassic Shanshen reservoir in Taibei depression
    LI Wei; FU Jiankui and QU Hui
    , 2002, 29(4): 217-0.
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    Great changes have been taken place in the reservoir of Triassic Formation in Shanshanstructure in Taibei depression, Tuha basin since its formation. Microscopic methods, such as hydrocarbon inclusion, K-Ar dating, fluorescence thin section analysis of oil-sand and macroscopic methods, such as thermal evolution of hydrocarbon source rocks, the formation of reservoir-cap rock assemblage, the formation and evolution of the trap, time of oil and gas migration, etc, were used for comprehensively studying the basin. The paper ascertains that if the early period of pool-forming is early J2q, the normal mature oil and gas filled in the pool; if the main period of pool-forming is early J3q, the high mature oil and gas filled in the pool; and if the main rework period of reservoir is early J3k, the pool would be filled in again mainly by high mature gas.
  • The structure feature of Qianmiqiao buried hill and its role in oil-gas accumulation
    WU Liquan; ZHENG Yumei; CAO Daiyong and WEI Yingchun
    , 2002, 29(4): 218-0.
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    Qianmiqiao buried hill is the most typical Cenozoic-generation-and-Paleozoic-reserving pool in Huanghua depression. Restoring the buried hill is one of the key and difficuly points to penetrate into the buried hill oil-gas pool. In this article， the inner buried hill structure was studied through tectonics-geomechanics methods, which pointed out that on the background of Indosinian anticline, the buried hill was formed through compressional orogeny at Yanshan movement, which was twicely tilted at Himalayan epoch for dextral extension, and it occured mass heat-subsidence after Neogene. The delta structure is the foundamental structure of the buried hill. The buried hill development is characterized mainly by two structural types of thrusting and imbricated fan and recoil fault. Tectonic movement was the key of oil-gas accumulation in the buried hill.
  • Periodicities of diapiric rise in the Yinggehai basin
    HUANG Chunju; CHEN Kaiyuan and LI Sitian
    , 2002, 29(4): 219-0.
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    The Yinggehai basin is characterized by high thermal gradients and overpressure. The diapir structure zone contains rich resources of oil and gas. However, so far the periodicity of diapiric rise in Yinggehai basin has not been cleared. The purpose of this paper is to make clear this problem and find the evidences. Through using the high-resolution sequence stratigraphic interpretation and pre-stack depth migration of seismic section, and analyzing fluid container parameters, the distribution of source rock and the basic periodicity of diapiric rise were determined. After precisely interpreting reflection termination and studying the forming procession of the diapir structure, it is found that the diapiric rises are characterized by multi-source and multi-episode, and the diapir structures by different periodicity, different step and vertical stacking. The multi-source rock and the special structural thermal system of super-high temperature and overpressure in Yinggehai basin made the diapir being characterized by fluid flowing. Through analyzing the result of the diapiric rise and the pooling mechanism, it clearly shows there had certain relation between the diapiric rise and the petroleum accumulation, the multi-episodic rise of diapir led to the multi-episodic injection of petroleum.
  • An approach to the generating mechanism of secondary pores and pore evolution model of He 8 gas layer in Suligemiao gas field
    LIU Ruie; SUN Fenjin; BAI Wenhua; MA Chenghua and HUANG Yueming
    , 2002, 29(4): 220-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Suligemiao gas field is another significant discovery followed the discovery of Yulin gas field in Ordos basin, however porosity genesis type between He 8 gas layer in Suligemiao gas field and that of Shan 2 layer in Yulin gas field has greater diversity. Through digenetic research, the sandstones of He 8 interval are of B period of the late diagenesis. According to systematic petro-mineral appraisal, environmental scan electron-microscope analysis, and energy spectrum, it is found that tuffaceous, unstable debris and unstable fillings are very excessive. Different types of secondary porosity are extensive. In order to study the origin of the secondary pores, acidolysis simulating experiment, under simulating stratigraphic conditions, has been developed. By the means of environmental scan electron-microscope analysis and energy spectrum analysis, the sample's variety before and after acidolysis corrasion has been contrasted. By the means of plasma emission spectrum analysis, the water sample's components after the acidolysis corrasion also have been tested. The results indicate that the tuffaceous sandstone's corrasion is very obvious, and the corrasion become serious as the acidity of acetic acid increased. The tuffaceous sandstone's corrosion capacity is 7.0-11.0 times that of the quartz sandstones. The felspathic corrosion lagged that of alter-tuffaceous matrix. Through analysis and research the author indicates that the main origin of the secondary pore is the corrosion of tuffaceous sandstone, and puts forward the new pore evolvement model of the tuffaceous sandstone.
    • 综合勘探开发技术
  • The mild oxidative degradation of the heavy constituents in viscous crude oil and oil sands
    LIAO Zewen and GENG Ansong
    , 2002, 29(4): 221-0.
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    Viscous crude oils and oil sands are important energy resources, but it is difficult to exploit them due to the dominated heavy constituents such as asphaltenes. In this work, the mild oxidative degradation of the heavy constituents (oxidized by NaIO4/NaH2PO4 and 30%H2O2/CH3COOH) has been carried out. In the viscous oil, more than 45% asphaltenes has been degraded, and the asphaltenes are mainly chemically changed into the resin fractions, which is favorable to the stability of viscous crude oil. After the degradation, the total amount of extractable organic compounds from oil sands is markedly more than that of the blank experiment. The experimental results indicate that the mild oxidative degradation of asphaltenes can improve the physico-chemical properties of the viscous oil and oil sands, which is particularly in favor of the exploitation of these energy resources.
  • Subtle oil reservoir discovery in Structure Ⅱ of Bayindulan sag, Erlian basin
    CHANG Liang; YIN Hongping; CHEN Yaqing and WANG Yuanjie
    , 2002, 29(4): 222-0.
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    Oil and gas exploration began very early in the Bayindulan sag of Erlian basin, but so far, no oil or gas was discovered there. The source rocks of the sag are good, but the large structureal traps are not matched with the favourable reservoir belt, so structural oil reservoirs have never been found within more than 20 years. Fortunately, from 2001, people put their focus on the prospecting for subtle traps, represented by using inversion softwares, such as STRATA, ISIS, JASON, carefully identifying the K1Ba lithologic body on the BaⅡ structure, building the model of structure-lithological reservoirs. After these, 5 exploratory wells were drilled, all of them produced commercial oil, and then the Baolige oil field with OOIP more than 10×106t was found, which has a production capacity of 7.68×104t per year.
    • 油田开发与油藏工程
  • Production characteristics and the optimization of development schemes of fractured gas reservoir with edge or bottom water
    SUN Zhidao
    , 2002, 29(4): 223-0.
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    This paper discusses the production characteristics and development scheme of gas reservoirs and gas condensate reservoirs with edge or bottom water and oil ring or bottom oil. The characteristics of this type of gas reservoir are the followings: (1) pore is the main storage space of fluid; (2) fracture is the main percolation flow channel; and (3) the distribution of pore and fracture is seriously heterogeneous. During the development process of the reservoir, its dynamic performance mainly are: edge or bottom water and oil will easily flow to producer along the high permeable fracture channel; and water influx into the gas-bearing area will heavily influence gas production, for example, forming gas, water (and oil) multi-phase flow, decreasing gas rate of producer, forming some water locked gas-bearing areas and reducing the recovery of gas and oil. The watered-out mechanism and its harm extent are discussed. Based on the principle of balanced production, this paper offers the optimal development scheme to avoid water influx, enhance gas and oil recovery and improve economic benefit. Three examples of mature gas fields are given in this paper.
  • The effect of sedimentary microfacies on single-well productivity
    HE Shunli; ZHENG Xiangke and WEI Junzhi
    , 2002, 29(4): 224-0.
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    递减曲线分析法、水驱曲线法和数学模型法等产量预测方法未把新区考虑在内而进行新、老区综合预测。提出综合预测新、老油区产量的多元线性混合回归模型方法，从影响产量的诸多因素中优选出显著因素，以此为基础对油田产量进行预测。为验证方法科学性及可行性，将其应用于某油区的“十五”规划产量的预测，得到了较为满意的结果。该方法简单、实用，突破了产量预测方法的常规模式，对其它领域的预测也有一定的借鉴价值。图1表3参5
  • Development evaluation method and its application result in difficult-to-recover reserve in Shenjiapu area
    LIU Shuming; DANG Hong; HE Xinrong; ZHAO Kunshan and DENG Shuyuan
    , 2002, 29(4): 225-0.
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    Zao IV and V payzones in Shenjiapu area of Dagang oil field belong to heavy and viscous crude reservoirs of complicated fault blocks. The density of degased crude oil is 0.9436g/cm3, the viscosity is 1381.3mPa.s, the gum and asphalt content is 45.07%, and the pour point is 30℃. Since structure is not determined, logging interpretation coincidence rate is low, crude oil property is poor, productivity is not practicable, these zones have not been put into development since 1971 after drilling. As difficult-to-recover reserves they have been carried out comprehensive evaluation from 1997. A series of research and pilot tests have been done toward many aspects such as three-dimensional seismic data reprocessing, structural reinterpretation, multiple-well logging evaluation, well test, producing test, corresponding production process to ascertain structure and obviously enhance single productivity. Integral development program is also compiled. Layer series of development are rationally divided. At the same time, development scheme and rational recovery rate are determined. There are altogether 39 drilled wells at Shenjiapu area to form a larger production capacity.
  • The mathematical well-test model for measuring after-flow rate and its interpretation method
    LI Xiaoping; WANG Lanlan and TANG Wenling
    , 2002, 29(4): 226-0.
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    In well test data of middle-late period of oilfield development, due to the perturbative phenomena of low permeability, well pattern or multi-layer reservoir, a lot of pressure build-up curves are hard to show a radial flow straight line period. Even in some wells, the shut-in time is very short, but they already showed the influence of boundary or cross-well interference. In this case, the general method of well test can't interpret these data. If using other methods of interpretation, it is often with multi-solutions. Analysis on the measured after-flow data indicates that once accurate pressure and after-flowrate are obtained, the short time well testing problem, which has not been solved by other well test interpretation methods for a long time, can be solved. As a result, a new method for using after-flow data to interpret well test results is put forward in this paper, which can provide an ideal interpretation results for the two cases as the measured data points falling into the areas above or below the semi-log straight line, and move up greatly the time of occurrence of the semi-log straight line, so, shorten the well shut-in time.
  • The application of fractal theory in progressive development of Shenquan oil field
    WANG Renyi; LI Xilian and ZHANG Pengyi
    , 2002, 29(4): 227-0.
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    The fractal theory as a mean of geological studies is worth much in application study. Taking Shenquan oil field in Tuha basin as an example, the fractal theory is used to describe sedimentary environment, fraction system and spatial distribution regularity of reservoir. Since all sedimentary environments of reservoir, fracture system of structure and spatial distribution of reservoir have the fractal characteristics, they can be quantitatively described by fractal theory. Fractal was used to summarize plane distribution regularity of fracture system of structure for Jurassic reservoir of Shenquan oil field. Based on it and other information, the sedimentary environment was identified and predicted. The spacial distribution of Shenquan oil field also has same fractal characteristics. Based on this, the potential and decision making of circumferential progressive exploration was predicted and supported. As the application and development in sand body prediction, well space optimization and development pattern selection, the prospect of circumferential progressive exploration and the prediction of resource capacity, fractal will play a more important part in oil and gas exploration and development.
    • 油田非注水开发
  • Application of heavy oil cold production technology in Henan oil field
    HU Changzhong; LIU Xinfu; YANG Zhibin and CHEN Xiaoxi
    , 2002, 29(4): 228-0.
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    In a cold production process, the well gets a high oil production with withdrawal of large amount of sand and formation of foamy oil. Henan oil field has reached abundant achievements, in cold production technology application and controlling the cold production strategies for heavy oil, and has practiced commercially in very-thin bedded and middle-depth heavy oil reservoirs. The first pilot well's oil rate was 8 times that of conventional test, and 4 times that of steam soaking. At the same time, the producing cost is less than that of steam soaking by 47%. Additionally, HPEB succeeded in low-cycle steam soaking wells, in which, daily oil rate is 1-3 times higher than that of steam soaking wells. Thus, the range of using cold production technology was further extended.
    • 油层保护与改造
  • Study and application of CO2 foam fracturing fluids
    DING Yunhong; CONG Lianzhu; LU Yongjun; LEI Qun; GUAN Baoshan and MU Lijun
    , 2002, 29(4): 229-0.
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    Foam fracturing fluids have been used to stimulate low pressure, fluid-sensitive formations. The characters of foam fracturing fluids have been recognized as leaving minimal damage to fracture conductivity, flowing back quickly, lowing leak off efficient, high efficient fluid, high viscosity and strong proppant-carring capacity. Parameters studied in the laboratory include: research and development system of CO2 foam fracturing fluid, optimization of the formulation and the properties of CO2 foam fracturing fluid being tested. In the end, conclusion drawn are (1) CO2 foam fracturing fluid have a strong foamability and foam-stability, predominate rheological and proppant-carring capacity, lowing leak off and quick breakdown as well, which are satisfied to fracturing technology and it has been confirmed by the experimental results of reservoir cores that CO2 foam fracturing fluid is characterized by lower expanding and damage for reservoir rock. (2) In the process of CO2 foam fracturing, CO2 foam fracturing crosslinked foam by acidity of agent have such capacities as improving dimensions of fracturing, increasing quantity of proppant and sand-fluid ratio. Increasing production of CO2 foam fracturing fluid has been testified in Changqing oil field.
  • The effect of suspended particles from injected water on the developmentof super low-permeability reservoirs
    YANG Zhengming; QIU Yongsong; ZHANG Xunhua and HUANG Lixin
    , 2002, 29(4): 230-0.
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    Water quality of injected water affects on the development efficiency of low-permeability reservoir, injuries the formation permeabi-lity, and makes water injectivity and oil productivity decrease in water flooding. Through the methods of physical experiment and reservoir engineering, this paper studies the effect of suspended particles from injected water on the injected pressure, formation permeability, and oil productivity in low-permeability reservoir. It is concluded that as rock permeability decrease, the value of injected pressure between injected water and formation water become larger, as the pore diameter of mesh filter decreases, the resistance force of percolation flow through porous media becomes small, and the injury of formation permeability becomes larger, when the formation is seriously injured by the suspended particles from injected water, the production and drainage radius in low-permeability reservoir become small. This paper gives theoretical instruction and calculation method for water flooding in low-permeability reservoir.
    • 石油地质研究
  • The correlation of natural gases with their source rocks in Ordovician buried hill of Qianmiqiao
    LUO Xia; HU Guoyi; ZHANG Fudong; LI Jian; JIANG Zhusheng; LI Zhisheng and ZHANG Ying
    , 2002, 29(4): 395-0.
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    The natural gas pool of Ordovician buried hill in Qianmiqiao in Huanghua depression is a great discovery. The comprehensive dynamic correlation methods of natural gases with their source rocks are applied in this article, such as different stratohorizion thermal simulation production of and thermal simulation gasoline hydrocarbon and thermal simulation carbon isotope ratio of Toluene, C1, C2, C3, C4 of rock, combining gasoline hydrocarbon and carbon isotope ratio of Toluene, C1, C2, C3, C4 of natural gases. The correlating conclusions are:(1) The natural gas pool of Ordovician buried hills in Qianmiqiao in Huanghua depression mainly came from Tertiary system which is at high maturity stage. (2) The condensate oil of Ordovician buried hill also came from Tertiary system, which is at mature stage.
    • 综合勘探开发技术
  • Logging identification and evaluation of Cambrian-Ordovician source rocks in syneclise of Tarim basin
    WANG Guiwei; ZHU Zhenyu and ZHU Guangyu
    , 2002, 29(4): 398-0.
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    From a long time in the past, it was very troublesome to evaluate source rock because of the insufficiency of the perforation. As a new branch of log-geology, log identification provides a feasible way. It makes full use of the log data with the high vertical resolution to carry out the prediction of total organic carbon. It provides the geological bases for the calculation of the reservoir and the strategy of gas-oil exploration. Based on the analysis of methods of ΔlogR , a basic model of source rock prediction is set up by the statistical theory and nerve network theory. Through practically applying it to some wells in Cambrian-Ordovician of Tarim, it is indicated that this method is useful, efficient and reliable.
  • An effective method for guiding drilling target selection by seismic reflection character
    LIANG Xingru; SHAN Baodong; ZHAO Zhengquan and LI Bo
    , 2002, 29(4): 399-0.
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    The structure and reservoir of Jizhong fault-block are very complicated, which makes the seismic reflection there “disorder”. But in this disorderly reflected area there exist relatively steady seismic reflections, which mostly represent the relative stability of the local strata or lithology. So, like searching the high resistivity layer in logging interpretation, searching the “relative steady” seismic phase with high amplitude in seismic interpretation, and then identifying the reservoir development area is an effective method to optimize drilling target and well location. Based on this, an optimizing drilling target method was put forward, which includes three aspects: ①interpreting the “relatively steady” strong seismic phase； ②analyzing the controlling factor of big fault in source rock on the “relatively steady” seismic phase；and ③looking for the “relatively steady” seismic phase on the structure background, and then delineating the favourable region.
  • Application of OFA quantitative callophane in Henan oil field
    YUAN Huai; ZHANG Genfa; CHANG Jianjun and Lü Wen-hai
    , 2002, 29(4): 402-0.
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    The quantitative fluorescence logging is a new technology that came into being in the last several years, which has changed the traditional fluorescence logging into quantitative analysis. It provides a new tool for us to discern and evaluate hydrocarbon beds. Especially, this technology shows strong vitality in distinguishing true and false oil and gas shows, discerning light oil, evaluating reservoirs and eliminating the influence of oil emulsion mud additive on well logging. Combined with the characteristics of quantitative fluorescence logging, the application method and result of this technology in Henan oil field has been introduced and the suggestion and direction of the spread of this technology has been proposed in this article.
  • The determination of organic acid in kerogen or coal by capillary electrophoresis
    WANG Huitong; YING Fengxiang; YOU Janchang; XU Guangjun and LUO Ping
    , 2002, 29(4): 403-0.
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    A method to determinate organic acid (oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexoic acid) in kerogen or coal by capillary electrophoresis is introduced in this paper. Organic acid in kerogen or coal is extracted using water in 105℃. The buffer is composed of 0.8mmol/L Potassium hydrogen phthalate and 0.4mmol/L Hexadecyltrimethyl ammonium bromide. The voltage during experiment was 25kv. The experiment results show that the repeatability and recovery of the method are satisfied. Some examples of the geology application using organic acid are given.
    • 油田开发与油藏工程
  • A new method of predicting oilfield output and its application
    LIU Xiuting; YANG Jun; CHENG Zhongping and WANG Shengyi
    , 2002, 29(4): 406-0.
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    Predicting oilfield output will go through all over the period of oilfield development. In particular, it is of great importance to oilfield development design. At present, there are many kinds of method of predicting oilfield output including decline curve analysis, waterflood curve and mathematical model. But these methods only predict output of mature blocks without considering that of new blocks. In order to solve this problem, predicting new and old blocks output model—multivariate linear mixture regression model was builds up, which is regar-ded as a new method of predicting oilfield output. At first, this model is used to optimize the prominent factors from many factors which effect variable output, and then to predict oilfield output which is based on these prominent factors．Meanwhile, this model is used to predict the output of X oil field during its tenth “Five-Year” period. For the sake of verifying its science and feasibility, the result is satisfactory. The method isn't only simple and practicable, but also breaks through the normal mode of output prediction and is used for reference to the other field prediction.
  • Numerical model of oil-gas flow draw-down test and its typical curve's characteristics
    LIU Liming; LIAO Xinwei; LIU Bailiang and CHEN Qinlei
    , 2002, 29(4): 407-0.
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    The paper presents the idea to solve the model of the oil-gas flow well testing numerically. The model is used then to analyze the characteristics of oil-gas flow in homogeneous reservoir. Through the solution of examples, the paper gives the characteristics of a typical drawdown type curve of oil-gas flow, shows how the initial saturation, the viscosity ratio of oil to gas, the saturation gradient and the relative permeability relationship affect the well testing curves, and answers why the above factors can do so. Though different reasons bring different results, there is a common point that: the presence of gas in reservoir induces a trough immediate after the hump on the derive curve. This novel point can surely improve the knowledge of multi-phase well testing.
  • Applying transient testing to the judgement of inter-well connectivity
    LIAO Hongwei; WANG Chen and ZUO Dairong
    , 2002, 29(4): 412-0.
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    It is very important to judge inter-well connectivity for gas felid exploitation, before a gas field putting into production; it has broad practicability to judge inter-well connectivity by reservoir pressure gradients. But along with gas field producting, gas reservoir pressure is changed, so it is limited in using originality reservoir pressure and pressure gradients to judge inter-well connectivity for new wells. Moreover, test period is very long and test rate is very high by using interference test to judge inter-well connectivity. Text discussed variety law of interfering well pressure build-up derivative of isotropic reservoir based on theory analysis, and compared with pressure build-up derivative form of supply boundary, the result of pressure build-up derivative of interference test is less than 0.5, and pressure build-up derivative of constant pressure boundary well is greater than 0.5 at first, then minish, finally it is less than 0.5. Based on this characteristic, inter-well connectivity can be judged and gas reservoir pressure system characteristic can be studied by transient test result and pressure gradients.
  • A study on a high-efficiency development model and its application in low-permeability sandstone reservoirs of Duanliubo oil field
    ZHANG Jialiang; ZHAO Pingqi; DUAN Hehai; WANG Deming; GUO Chundong; DENG Maoping and XU Chunmei
    , 2002, 29(4): 413-0.
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    Duanliubo reservoir in Dagang oil field was put into development in 1985. Due to low permeability and strong and heterogeneity, this sandstone multi-layer reservoir kept a low production rate and low efficiency after development. After analyzing the main factors which affect the production, such as geology and fluid factors, a development model which is suitable for Duanliubo reservoir was found. From 1996 to 2001, adjustment was done to improve Duanliubo development level. The wells doubled, and their production was increased by 10 times. The full field development was greatly improved.
    • 油田非注水开发
  • Sensitivity analysis of some parameters for MEOR
    CHEN Junbin; ZHANG Rongjun and WANG Zhitai
    , 2002, 29(4): 420-0.
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    Using a 1-dimensional, 3-phase mathematical model of microbial flooding, which is established preliminarily to describe the transportation of microbes in an oil reservoir, the sensitivity analysis of some parameters for MEOR was accomplished. The research manifests that (1)there is a best velocity of injected bacteria flow in the course of MEOR process； (2)the higher the bacteria initial concentration is, the faster the bacteria concentration's increment is and the bigger the bacteria deposited concentration is at the bottom of water injection well；and (3)the higher nutrient initial concentration is, the bigger bacteria growth rate is.
  • Crosslinking under shear
    HU Jinghua; LIU Yuzhang; BAI Baojun; LI Liangxiong and Cost JeanPau
    , 2002, 29(4): 421-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    In water shut-off operations, the polymer solution and the crosslinker are currently mixed into surface facilities just before to be injected through the production or injection well and then inside the reservoir. Therefore, the crosslinking system is always subjected to shear stresses while gelling, so, the process of the crosslinking under shear should be studied. This paper reports a theoretical and experimental investigation of the process of the crosslinking under shear. The proposed theory describes the crosslinking under shear as a four successive steps process, and a solution of monodispersed microgels is obtained at the end of the final step. New experimental data, obtained by using a low toxicity crosslinking system, i.e. a weakly hydrolyzed and sulfonated polyacrylamide together with Al3+ are reported, the authors of this paper also analyzed the effects of Al3+ concentration, pH, rheometer gap and applied shear rate to the crosslinking system under shear, found that the final shear viscosity, the characteristic time Tg are all influenced by the shear rate, therefor new monodispersed microgel can be prepared under the proper condition under shear.
    • 油层保护与改造
  • A laboratory research for the sand-production mechanism of viscousoil reservoirs in Fula oil field
    WANG Yongli and ZHANG Baoping
    , 2002, 29(4): 432-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Fula oil field is a main oil field found in the exploration and development of the 6th zone (Unit 6) of Sudan. It consists of Bentiu Formation and Aradeiba Formation with the crude oil viscosity of 300-500 mPa.s under reservoir condition. Severe sand production occurred during perforation and well testing. To find out the cause of sand production in order to take appropriate sand control measures, rock mechanics experiment research was carried out for Bentiu Formation. Mohr-Couloumb failure envelope was obtained through triaxial test under different confining pressure. Tested cylindrical samples were from unconsolidated formation sands. Experimental results showed that cohesion strength of Bentiu Formation sand was very low (1.5MPa) and premature sand production would occur even under low drawdown pressure. So it is not practical by controlling drawdown pressure. In addition, cohesive failure of the formation would finally lead to shear failure as more and more sands were dragged out and severe sand production would start. Therefore,it is necessarg to control the sand produition and producing pressure differential at the early stage of putting oilfield in production.
    • 石油地质研究
  • The combination pattern of clay minerals of sandstone and mud rock in China's petroliferous basins
    WANG Xingxin and HAN Shouhua
    , 2002, 29(4): 437-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The combination pattern of associated clay minerals are classified into two major categories with twelve types by geological feature and X-ray diffraction analyses of more than one hundred thousand samples of sandstones and mud rocks fifteen petroliferous basins of China, each type represents different sedimentary and diagenetic environments respectively. The first to the fifth normal types represent five kinds of different diagenetic environment that include early diagenetic stage A and stage B, and later diagentic stage A, stage B, and Stage C. The sixth type commonly happens in high permeability reservoir or coal measures strata, the seventh one often happens in low permeability reservoir of oil generation depression. The five special types of combination pattern of associated clay minerals represent the following different sedimentary environments:(1)bentonite band; (2)the environment of continuous denudation of deep-stratum and quickly accumulation; (3)source area of basic volcanic rocks; (4)the sedimentary environment of quickly degradation and accumulation of potassium-rich materials and (5)the arid sedimentary environment of magnesium-rich materials.
  • Study on the interaction of overpressure and hydrocarbon generation and the influence of overpressure upon hydrocarbon accumulations
    WANG Zhaoyun; ZHAO Wenzhi and HE Haiqing
    , 2002, 29(4): 448-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Overpressures are widespread throughout the global oil and gas basin and have great influence to exploration. A variety of processes have been proposed for the generation of overpressure, it can be summarized into three types, compaction disequilibrium, tectonic compression and fluid affection. In the latter case, fluid process includes hydrocarbon generation, aquathermal expansion, clay mineral dehydration etc. It is indicated that overpressure and evolution of source rock is interactional and inter-restricted. On one side, the large generation of hydrocarbon, specially the large generation and migration of gas or the block of migration resulted in overpressure; on the other side, overpressure restrained thermal evolution of source rock due to the decrease of hydrocarbon generation rate and made oil window deeper. Overpressures reduced the compaction and improved the reservoir quality. In addition, overpressure changed the in-situ stress conditions under which the rock broke, and resulted in the development of fractured shale reservoirs. Overpressure is the motive power of hydrocarbon migration and controls the hydrocarbon accumulation. If the formation of overpressure in the trap is earlier than the charge of hydrocarbon, it is not good for the hydrocarbon accumulation; otherwise, it is very benefit for hydrocarbon accumulation if the formation of overpressure is the result of the hydrocarbon charge. Commonly, the hydrocarbon accumulated mainly in the transition zone of overpressure body.
  • An approach to the timing formation for primary oil pools of Ordorvician system in Kongxi buried hill
    CHENG Keming; XIONG Ying and ZHANG Xiaobao
    , 2002, 29(4): 449-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Primary oil pool of Ordovician system (at Well Konggu3 and Well Konggu7) and primary oil and gas pools of Carboniferous-Permian system (at Well Konggu 4) were found in Kongxi buried hill of Huanghua depression. The result of oil-source correlation shows that the first kind of oil mainly sourced from limestone of Majiagou Formation of Middle Ordovician, and the latter mainly from mudstone of coal measure strata of Taiyuan Formation of Carboniferous system and Shanxi Formation of Permian system. According to the K-Ar isotope data of authigenic illite and the measure of two-period fluid inclussion of the reservoir of Well Konggu 3, the oil pool formed in two periods, which are late Triassic (about 222.51 to 240.34 Ma ago) and Tertiary (mainly late Tertiary).
  • Permian unconformity and its effect on petroleum migration in the circum-Mahu depression of Junggar basin
    CHEN Jianping and ZHA Ming
    , 2002, 29(4): 472-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Unconformity textures and distribution are studied in the circum-Mahu depression of Junggar basin through seismic profile and lithology analyses, and four types of unconformity structure are classified, i.e. the combination of volcanic breccias and eluvium (mud seal), the combination of volcanic breccia and basal conglomerates, the combination of clastic rocks and eluvium (mud seal), the combination of clastic rocks and basal conglomerates. The extensional cracks in volcanic rock unconformity are the main passage for oil infiltration; the erosion belt or/and overlying basal conglomerates under clastical unconformity provided the major pathway for oil migration.
  • An analysis of deep hydrocarbon accumulation conditions and exploratory realms in the heartland of Junggar basin
    YANG Yongtai; WANG Shejiao; PEI Donghong and XING Ya
    , 2002, 29(4): 473-0.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    Through analyzing the effect of thermal history, thermal evolution history of hydrocarbon source rock, trap-forming history and early charging of oil and gas on the reservoir evolution, it is indicated that deep strata of central Junggar basin has favourable conditions that could form a large oil field. It was considered that high palaeogeothermal system in Junggar basin caused early mature and hydrocarbon generation of Lower-Permian source rocks and most of them were at hydrocarbon generation peak in the end of the Triassic, and almost at the same time, the deep traps of central Junggar basin basically falled into a pattern in the end of the Triassic or some early time before the Triassic, and in addition they were extremely matched with hydrocarbon generation history, which could result in hydrocarbon accumulation before the end of Triassic. The early charge of oil and gas could restrain pore evolution. In addition, deep strata characterized by early pool-forming should have good reservoir properties. Beside, the authors discussed the pool-forming characteristics in deep strata, including reservoir properties, overpressure and pool-forming models, etc.
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