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    20 October 2009, Volume 31 Issue 5
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    地质勘探
    MULTI-DOMAIN INFORMATION ASSESSMENT OF OIL & GAS TRAPS BASED ON CLOUD MODEL AND GREY RELATIONAL ANALYSIS
    WU Guo-pinga AO Min-sia WU Yi-qib XU Hong-yan WANG Xiao-minga
    2009, 31(5):  1-5.  DOI: 10.3863/j.issn.1674-5086.2009.05.001
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    Cloud model，which is proposed based on the traditional fuzzy mathematics and probability statistics theory，is a conversion model between qualitative concept and quantitative values.In order to establish the quantitative and qualitative relationship between oil & gas reservoir and the trap area，trap closure amplitude，hydrocarbon migration channel，formation porosity，the relationship among the oil generation，trap forming and special compatibility，the imposed threshold was frequently involved in traditional way of multi-domain information assessment to build the relation model，which is limited by the experiences of experts to a great extent.With consideration on the fuzziness，randomness and uncertainty of small samples，a new approach to multi-domain information assessment based on cloud model and grey relational analysis is presented in this paper.With assessment to the traps of Shuntuoguole in Northwest China，type Ⅰ，Ⅱand Ⅲ traps are identified.Among them，typeⅠ accounts for 37.5% of the total，type Ⅱ takes up 37.5% and the proportion of type Ⅲ is 25%，which is consistent with practical development assessment.

    IDENTIFYING ABANDONED CHANNEL BASED ON TIME SERIES
    JIN Zhi-yong GAO Wen-kai HAN Dong ZHANG Yun-yi YIN De-sen
    2009, 31(5):  6-8.  DOI: 10.3863/j.issn.1674-5086.2009.05.002
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    Time series，which is an important branch of stochastic process，is applied to the analysis of sedimentation sequence of rocks.The vertical log profile is treated as time sequence data，so the well logs can be formulated by the auto-regression model of time series.Also，the parameters of the model can be estimated by the least squares estimation with well log data.That means the estimated model has learnt the deposition sequence on the spot of the corresponding well.At last，the model is used for verifying other wells whether they are of the same facies as the first well.This method is applied to identification of abandoned channel facies in Daqing Oilfield.The results show that，to the logging curves of the wells which are located at the same depositional facies，the error between estimated value and practical value is smaller and to the curves of the well located at abandoned channel，the error is greater.The conclusion that time series can be applied on the whether the wells are of the same depositional facies is drawn.

    A NEW CORRECTION METHOD OF SKIN EFFECT FOR INDUCTION LOGGING
    SONG Xi-jin LI Li-pin DANG Rei-rong
    2009, 31(5):  9-12.  DOI: 10.3863/j.issn.1674-5086.2009.05.003
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    Aiming at the problem of skin effect for induction logging，the authors of this paper adopt the real component or both the real and the imaginary component of the apparent conductivity to achieve the correction of skin effect of composite-coil induction logging measurement signal.The iterative correction is achieved with the iteration of the skin depth.When the real and the imaginary component of the apparent conductivity is used to fulfill iteration，the correction results are almost entirely consistent with the formation conductivity.When the real component is used only，the correction error shows slight increase but it can be improved by using the iteration number.In addition，this method converges within the common range of the earth conductivity.Numerical results indicate that the method is simple in iterative formula，specifically physical meaningful，highly accurate and applicable to various coil system.

    RESERVOIR EFFECTIVENESS EVALUATION FOR T1j2 STRATA IN MOXI AREA
    ZHAO Hui DAI Shi-hua SIMA Li-qiang YAN Qi-Bin
    2009, 31(5):  13-16.  DOI: 10.3863/j.issn.1674-5086.2009.05.004
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    Viewed from conventional physical property and well logging response，there is similar reservoir characteristic between T1j21 & T1j22，they are all good reservoirs.NMR analysis of the cores from T1j22 indicates that there are big difference in pore structure in T1j21 & T1j22.Although there is higher porosity in T1j21，the poor spaces are taken up by irreducible fluids.The NMR data can be used to evaluate the reservoir effectiveness.To T1j21 ，the pore spaces are mainly taken up by mobile fluids，the throat radius method can be used to determine the limit of effective reservoirs，and it can be used as criteria to assess effective reservoirs.

    THE APPLICATION OF GAS BUBBLE-PRESSURE METHOD IN THE STUDY ON RESERVOIR PORE STRUCTURES
    XIE Xiao-yong;a TANG Hong-ming;bMENG Ying-feng;a LI Gao;a ZHAO Feng;b
    2009, 31(5):  17-20.  DOI: 10.3863/j.issn.1674-5086.2009.05.005
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    The conventional methods for testing reservoir pore structure are mercury penetration and cast thin slice analysis.Gas bubble-pressure method is based on physical law of liquid flowing in pore，which can truly reflect the reality of liquid flowing through throats.The results of gas bubble-pressure and mercury penetration is compared with those of mercury in the paper.The tested main pore throat diameter of the latter is 2-4 times larger than the former′s.However，the distribution features of effective throat participating in flow through porous media tested in the former is more correspondent to project needs.It can obviously characterize the differences between effective throat distribution features of rock samples before and after hydration or acidizing，so the results have powerful comparability and high value.Gas bubble-pressure ethod provides a new way to test reservoir pore structures.

    PREDICTION AND ASSESSMENT OF FRACTURE HEIGHT OF HYDRAULIC FRACTURING WITH LOGGING DATA
    YI Xin-min TANG Xue-ping LIANG Tao LIU Xiang-nan
    2009, 31(5):  21-24.  DOI: 10.3863/j.issn.1674-5086.2009.05.006
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    There is a close relationship between the fracture height of hydraulic fracturing and the plan applied in fracturing operation，also，the height is a important parameter to evaluate the effectiveness of reservoir acidizing and fracturing.There was not quantitative way to predict and assess the height previously，which could only be assessed qualitatively after operation to a large extent.Study indicates，by using array acoustic data，casing pipe cross-dipole shearing wave logging data，the fracture height of hydraulic fracturing can be accurately predicted and tested，so as to guide and assess fracturing operationquantitatively.Case study shows the way can be used to effectively forecast the fracture height of hydraulic fracturing.

    HYDROCARBON CONDUCTING SYSTEM AND ACCUMULATION MODEL IN WUERHE-XIAZIJIE AREA OF JUNGGAR BASIN
    WU Kong-you
    2009, 31(5):  25-30.  DOI: 10.3863/j.issn.1674-5086.2009.05.007
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    In Wuerhe-Xiazijie Area，oil and gas have been discovered in ten formations of Permian，Triassic and Jurassic strata.According to the origins and sealing conditions，the reservoirs can be divided into six types，they are anticline reservoirs，fault block reservoirs，unconformity reservoirs，heavy oil sealing reservoirs，lithology-pinchout reservoirs and fault-lithologic reservoirs.Because of the multi-period tectonic movements，multi-period fault systems，many unconformities and connected sand bodies，which constitute the three-dimensional net migration systems，were formed.Sand bodies in middle and lower Triassic strata are extensively developed and best connected.Unconformities at the bottom of Jurassic strata，which have good layered structures，are good places for hydrocarbon migration and accumulation.Fault activities in Indo-Chinese epoch，which were in the same period with the hydrocarbon expulsions from source rocks，created the vertical migration pathways，and the fault activities decreased after the Indo-Chinese epoch when oil and gas were trapped in the lower wall of the faults.In terms of the sources of oil and gas，migration pathways and directions and the reservoir-forming periods，the accumulation models can be divided into four types：“一”- like accumulation models，“Y” -like accumulation models，“Z” -like accumulation models and “多”- like accumulation models.

    KEY SEISMIC TECHNOLOGY ON OIL-GAS EXPLORATION IN SOUTHERN MARGIN OF JUNGGAR BASIN
    Paerhati QIAN Gen-bao JIANG Zai-chao ShakirShamshy XIAO Li-xin
    2009, 31(5):  31-36.  DOI: 10.3863/j.issn.1674-5086.2009.05.008
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    Although the oil-gas resources of southern margin of Junggar Basin are very abundant，geologic condition is so complicated that the quality of seismic data is very bad，signal-to-noise ratio is low，static correction problem is apparent，the difficulty of imaging is big and the precision of structure mapping is poor.For resolving these four big problems，the idea，method and flow on sophisticated structure study in piedmont are put forward in this article.Omnibus key technique is adopted，tackling key problem carried out by integrative study mode of acquisition，emphatic structure target of southern margin （Horgos anticline） processed and interpreted，a set of structure traps which have the value of drilling and offering well site disposition is fulfilled.

    PROTOTYPE BASIN AND THE EVOLUTION IN JURASSIC AND CRETACEOUS IN EASTERN NORTH CHINA
    PENG Zhao-meng PENG Shi-mi WU Zhi-ping LI Wei KONG Xu
    2009, 31(5):  37-42.  DOI: 10.3863/j.issn.1674-5086.2009.05.009
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    Based on the research of distribution，lithologic feature of strata and regional tectonic evolution of remnant basins，prototype basin in Jurassic and Cretaceous in the Eastern North China are reconstructed.The researches show that in Early and Middle Jurassic，the Eastern North China was in the transitional period from Paleo-Asian system to Paleo-Pacific system，there were a series of small intermontane basins in the Bobai Bay area，sediments filled the depression formed by Indosinian thrust faults and gentle fold at the early stage and widely distributed at the late stage.From Late Jurassic to Early Cretaceous，tectonic and basin evolution were influenced by the Izanagi plate′s subduction to Asian continent.This Geotectonic transition led to the formation of large-scale rifts or faulted basins.Basin distribution and sediment filling were controlled by NW/NWW-trending and NE/NNE-trending fault systems.In Late Cretaceous，the areas to the west of the Tancheng-Lujiang fault zone were uplifted and denuded，with deposition of red fluvial-lacustrine sediments in a few basins.The remnant basins were the reflection of original sedimentation and late denudation.

    PETROLEUM GEOLOGIC CHARACTERISTIC AND PROSPECTING TARGET IN QINGDONG SAG
    SHI Pi-tong FANG Xu-qing CHEN Tao FU Zhao-hui ZHANG Zai-zhen
    2009, 31(5):  43-48.  DOI: 10.3863/j.issn.1674-5086.2009.05.010
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    Pool-forming conditions in Qingdong Sag is discussed on the basis of analysis on structure，formation and deposition.Structural framework in Qingdong Sag is fault subsidence in the east and overlap in the west，and depression alternates with uplift because of the effect of Yi-Shu fault belt activity and Dongying movement.Resource abundance in Qingdong Sag is high owing to high organic content of oil source rock.Source material type is kerogenⅠ-Ⅱ1 and in low mature to mature stage.Paleogene Shahejie formation is interstratified between sandstone and mudstone，“self-generation，self- reservoir and self- seal” pool-forming types are common.Sideway and short distance hydrocarbon migration in Qingdong Sag is main with strong structural segmentation，major fault activity was weak in late period and hydrocarbon generation and expulsion is late.So the traps being close to deep depressions and associated with fault are the most favorable targets for prospecting.

    EFFECTS OF MM-LEVEL MUD-FILMS ON RESERVOIR DEVELOPMENT IN YINGTAI AREA
    WANG Yong-zhuo;GUO Hong-yan CHEN Guo-xun WANG Hai-qiao
    2009, 31(5):  49-55.  DOI: 10.3863/j.issn.1674-5086.2009.05.011
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    There are abundant mm-level mud films in the cretaceous delta front silts in Yingtai area which is located in west of Daqing，with the thickness less than 3mm.The mud films are mainly developed in the sand sheet of delta front，secondly of mouth bar，and least in the under-water distributary channel.The frequency of the mud films in sand sheet is up to 40n/m by cores counting.Mud films can change the route of the oil-water migration in reservoirs and take effects of decreasing porosity and permeability indirectly.A work of exploitation numeral simulation by two models is considered，one is homogeneous and another is developed some mud films.The affections of mud film are quantitatively conformed by the contrast of two simulate results，and so some exploitation measures are brought for the reservoirs which contain some mud films in Yingtai area.

    IDENTIFICATION OF ALGAL LIMESTONE RESERVOIR WITH LOGGING IN YUEXI AREA，QAIDAM BASIN
    LI Yan-li;GOU Ying-chun;CAO Zheng-lin;SUN Xiu-jian
    2009, 31(5):  56-60. 
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    Algal limestone is widely distributed in Tertiary lacustrine strata in the west part of Qaidam Basin，and is one of the most important carbonate reservoir types.Reservoir property of the types is excellent，and single well productivity is high，so it is a new exploration field in Yuexi area.But algal limestone is thin in thickness，interbedded sedimentary rocks，and diversity in lithologies，so it is rather difficult to identify and evaluate.In this paper，starting from logging response characteristics of algal limestone，based upon identifying reservoir with lithologic logging overlapping with acoustic logging curve，algal limestone is identified by using 3-porosity curves overlapping each other.This method has good effect and provide a new thought and method for identifying the kind of complicated reservoir.

    THE CHARACTERISTICS AND DISTRIBUTION OF THE RESERVOIRS FROM SINIAN TO TRIASSIC IN NORTHWEST HUNAN
    LI Cong;CHEN Shi-yue;ZHANG Peng-fei;YANG Huai-yu;LUAN Shou-liang
    2009, 31(5):  61-67.  DOI: 10.3863/j.issn.1674-5086.2009.05.013
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    Reservoirs in Shimen-Sangzhi from Sinian to Triassic mainly include two categories，namely，carbonate rocks and sandstone.On the basis of observation and detailed study on a large deal of common and casting rock thin section，the reservoir space in Shimen-Sangzhi from Sinian to Triassic is divided into primary remaining intergranular pore，secondary intergranular dissolution pore，secondary intragranular dissolution pore，pane pore，super large dissolved pore and cracks according to the structure and cause of the pores.Sedimentation and late diagenesis are found to be the main control factors of reservoir physical property in the area through analysis of the characteristics of reservoir physical property.And the influence of sedimentary facies on reservoir physical property is decisive.Accordingly，reservoir distribution is summarized.Generally speaking，in this set of formation，there are various types of reservoirs，but with poor reservoir physical properties，low porosity and low permeability reservoirs are dominant，except that the sandstone in the upper triassic Yingju formation is of good reservoir property.

    CURRENT RESEARCH SITUATION AND THE PROBLEMS OF VOLCANIC ROCK RESERVOIRS
    SHI Leia LI Shu-bingb HUANG Lianga PENG Junb
    2009, 31(5):  68-72.  DOI: TE122.2
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    In recent years，as the breaking through progress of the exploration and exploitation for volcanic rock reservoirs，the reservoirs have become new targets for exploration and exploitation.On the basis of studying the existing literatures on the reservoirs home and abroad，the particularity of the volcanic rock reservoirs，the types and the genesis of reservoir space，the evolution feature of the space and the types of reservoirs are summered.Volcanic rock reservoirs are not in some lithologies，there is huge difference between it and sedimentary rock reservoirs.The reservoir space of volcanic rock reservoirs can be grouped in to four types according to the genesis，i.e.，primary pore，second pore，primary fracture and secondary fracture，its formation and evolution underwent five stages，i.e.，primary formation stage，weathering leaching stage，shallow bury digenesis stage，tectonic faulting stage and deep bury dissolution stage.At last，it is pointed out that there still are some problems in volcanic rock reservoir research，and research approach in the future is presented aiming at the problems.

    THE CHARACTERISTICS OF LOW-PERMEABILITY RESERVIOR OF Es2 UPPER 4-7 BODY GROUP IN THE SOUTHERN AREA OF PUCHENG OILFIELD
    XIAO Shu-ming;ZHONG Jian-hua;WANG Yong MA Feng
    2009, 31(5):  73-78.  DOI: 10.3863/j.issn.1674-5086.2009.05.015
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    The characteristics of Es2 upper 4-7 body group reservior in the southern area of Pucheng Oilfield are investigated with the data of thin section analysis，SEM，porosity and permeability analysis，core，log and geologic model.It is recognized that the pore space of reservoir mainly includes the primary residual intergranular pores and secondary intergranular pores.Displacement and saturation median point pressure is high，pore throat radius is small，pores throat sorting is poor and skewness is fine.The quality of reservoir is affected by sedimentary microfacies and diagenesis.The sedimentation is a basic factor generating low-permeability reservoirs，and the strong compaction and cementation are the key factors forming low-porosity and low-permeability reservoirs.According to the petrophysical properties of reservoir and pore structure parameters，Es2 upper 4-7 body group reservoir is classified into four types，the type Ⅰ and type Ⅱ are mainly distributed in the underwater channel and estuarine far-bar sandstone.

    石油与天然气工程
    THE STUDY ON OPTIMIZING THE PROPPANT QUANTITY IN FRACTURING BY SVM
    GUO Jian-chun;ZOU Yi-feng;DENG Yan;FU Chun-mei
    2009, 31(5):  79-82.  DOI: 10.3863/j.issn.1674-5086.2009.05.016
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    Fracturing effect is affected by many factors.There is the nonlinear relationship between the effect and reservoir parameters and reservoir conditions.In view of the difficulty of determining the sanding scale in designing fracturing process，the data of pre-fracturing well are used as sample data，the influence of net thickness，oil saturation，porosity，permeability，sanding scale and sand ratio on fracture effect should be considered，samples are learned by SVM，the forecasting model between influencing factors and fracture effect is established in the purpose of predicting the fracture effect under the different sanding scale，thereby the sanding scale is optimized.It is showed by calculation of case study in fracturing wells and the field implement that SVM has a fast convergence speed and can overcome effectively the problem of small samples，and optimal results effectively coincide with the actual fracturing effect，so it has a certain guiding sense to designed the sanding scale in fracturing.

    NONLINEAR PARAMENTR IDENTIFICATION OF RELATIVE PERMEABILITY CHARACTERISTIC PARAMETER IN OIL AND GAS RESERVIOR
    LI Hai-taoa TANG Qing;WU Jie-sheng;TAN Canb
    2009, 31(5):  83-88.  DOI: 10.3863/j.issn.1674-5086.2009.05.017
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    The determination of relative permeability curve for complex multiphase system while flowing through porous media is very important to understand the percolation mechanism，a basical and necessary information is provided for numerical modeling and prediction of production performance in oil &gas reservoirs.In this paper，the unsteady-state displacement method is employed to model the real scenarios of complex multiphase flowing in sandstones，and the pressure and flowrate data for each phase during the displacement process are used to estimate the relative permeability characteristic parameters through nonlinear system parameter identification technology.The self-adaptive step of the relative permeability characteristic parameters during iteration is based on the LMF method and optimal control theory.It is shown that the relative permeabilities obtained by parameter estimation are in good accordance with experimental results，and it provides a fast and reliable method to attain relative permeabilities with full-range of saturation and avoidance the limitations of conventional method.

    LOW PERMEABILITY FORMATION CHARACTERS
    XIONG Wei LIU Hua-xun GAO Shu-sheng HU Zhi-ming XUE Hui
    2009, 31(5):  89-92.  DOI: TE348
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    The low permeability formation characters of different oil fields are much different，which affects the ability flowing through porous media and development effect.Constant rate Hg injection test，NMR test，threshold pressure gradient to flow test and clay analysis are carried out on low permeability cores from Daqing and Changqing Oilfields to study their formation properties and characters of flow through porous media.Research results indicate that the main flow throat is the main controlling factor for ability flowing through porous media.The amount and types of clay minerals and movable fluid saturation decrease the effective size of flow channels especially for Daqing low permeability formation with high amount of clay.For Changqing and Daqing Oilfields，even with the same gas permeability，the main flow radium and movable fluid saturation of low permeability reservoirs in Changqing are much bigger than those in Daqing，while the threshold pressure gradient of low permeability reservoirs in Changqing is much lower than that in Daqing，which indicates why it is easier to develop low permeability reservoirs in Changqing than to develop the low permeability reservoirs in Daqing.
    FLOW UNIT AND REMAINING OIL DISTRIBUTION IN COMPLEX FAULTED-BLOCK RESERVOIR
    HU Shu-yong HU Ren-quan LIU Qi-guo
    2009, 31(5):  93-96.  DOI: TE347
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    At the present，QL complex faulted-block reservoir has come to the producing stage with middle to high water cut.There is more complicated remaining oil distribution.The geological model of flow units is set up based on sedimentary facies belts，lithologic，physical properties，heterogeneity，structure and the shape of sand body distribution by firstly considered the static parameters （geologic factors） infelicity the remaining oil distribution，the flow units are reasonably and accurately delimited.The water displaying oil characteristic and flood out pattern in different flow units are studied by combing dynamic and static data，the distribution law of oil，gas and water after flooding out is re-recognized.On the basis of that，the distributing law of remedies oil in different flow units is studied and the favorable regions for enhancing recovery are figured out，remarkable results are achieved.Chancing remains oil recovery in the complex faulted-block reservoirs in high water cut stage can take the method as reference.
    THE INFLUENCE OF CAPILLARY NUMBER EFFECT ON DELIVERABILITY OF CARBONATE ROCK GAS CONDENSATE RESERVOIRS
    LI Yong HU Yong-le LI Bao-zhu ZHANG Jing
    2009, 31(5):  97-100.  DOI: 10.3863/j.issn.1674-5086.2009.05.020
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    Retrograde condensation can seriously pollute formation.The capillary number effect can reduce the impaction.With the development of Tazhong No.I carbonate rock gas condensate reservoirs in China，it becomes more and more important to study the influence of capillary number effect on deliverability of carbonate rock gas condensate reservoirs in order to guide the field development.The definition of the capillary number effect and its influence on relative permeability curve are presented.Through a dual-permeability simulation model，this research gets the capillary number effect on well deliverability for different flow fluid property，formation permeability and pressure drawdown rate conditions.The results show the deliverability is significantly improved if the capillary number effect included.When formation pressure is higher than the dew point pressure，capillary number effect has no effect on well deliverability，however，it has the largest effect just when formation pressure is smaller than the dew point pressure.And then its effect drops.The larger the initial gas-oil ratio is，the higher the pressure drawdown rate is，the smaller the permeability of matrix and fracture s
    PHASE BEHAVIOR CHARACTERISTICS OF GAS WELL WITH RICH-CONTENT CO2
    REN Shuang-shuang YANG Sheng-lai ZHU Hai-peng FAN Zhao-wei SHEN Fei
    2009, 31(5):  101-104.  DOI: 10.3863/j.issn.1674-5086.2009.05.021
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    The phase behavior parameters such as gas deviation factor Z，density and the change with different CO2 content are studied by means of experiment，the physical factors such as pressure and temperature which influence phase behavior change complicatedly along wellbore，the factors if associated will result in more change，which can not be tested one by one，to the gas wells with different CO2 content the calculation model of temperature and pressure for conventional gas well，as well as different CO2 content phase behavior equation，is used to modify deviation factor，the distribution of pressure and temperature is calculated with numerical method through programming non-linear equation，then，the phase behavior parameter deviation factor Z and the distribution of density are calculated.The phase behavior of gas well with rich-content CO2is researched through related case study，it is recognized that the flowing gas collum with rich-content CO2 in different wellbore section forms saturated steam phase，under saturated steam phase and gas phase，liquid phase and gas liquid transition phase are formed while the distribution of gas phase is static，there is the reversion phenomenon of heavier upper part and lighter lower part in gas phase，a comparison is made between experimental result and field testing result，the phase behavior characteristics are basically consistent.
    THE WELL AND LAYER SELECTION IN FRACTURING IN ULYASTAI SAG
    ZENG Fan-hui LIU Lin WANG Wen-yao WANG Xin-wen
    2009, 31(5):  105-108.  DOI: 10.3863/j.issn.1674-5086.2009.05.022
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    The sandstone and conglomerate reservoirs in Ulyastai Sag are characterized by strong sensitivity，developed micro-structures，low inter layer stress，low productivity after perforation and the huge difference in effectiveness after fracturing.Precisely and quantitatively selecting the best potential fracturing wells and layers have been the bottleneck in developing the reservoirs.According to the statistic analysis to the data of previous fractured wells，the formation coefficient，porosity and oil saturation etc，as well as displacement amount，proportion of pad fluid and sanding strength，are taken as the main factors influencing fracturing effectiveness.The expert database of the fractured wells is set up.Regression analysis and BP neural network are used to optimally select 3 waiting-for fracturing wells.Practice indicates that there is a nonlinear relationship between the factors and the fracturing effectiveness，the linear regression can not meet the requirement of optimally selecting fracturing wells，the matching error of second order regression and neural network method is 0，predicted error is less than 2%，which can reach the standard of in-situ selecting fracturing wells and layers.
    SULFUR DEPOSITION MECHANISM OF THE GAS RESERVOIRS WITH HIGH SULFUR CONTENT
    FU De-kui GUO Xiao DU Zhi-min LIU Lin-qing DENG Sheng-hui
    2009, 31(5):  109-111.  DOI: 10.3863/j.issn.1674-5086.2009.05.023
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    Sulfur deposition is the one of the key issues，which universally exists and must be solved in the process of development of the reservoirs with high sulfur content.The research on the sulfur deposition of the reservoirs with high sulfur content is the foundation of studying sulfur deposition prediction technology of the reservoirs with high sulfur content，precisely handling sulfur deposition dynamic performance in formations and guiding effective development of the reservoirs with high sulfur content.On the basis of analyzing H2S content change law in the process of developing the gas in the gas reservoirs with high sulfur content，the chemical reaction equilibrium theory of inorganic chemistry is introduced to establish formation sulfur saturation calculation method，taking W gas field as example，the amount of element sulfur precipitated from polysulfide decomposition in different distance from wellbore when the formation pressure decreases to different degree is predicted，and comparison between the amount and the total precipitated amount calculated with analytic model is conducted.Result indicates that，in the process of the development of the reservoirs with high sulfur content，under the condition of minor sulfide content change，the sulfur content precipitated from polysulfide （H2Sx+1） takes very low proportion of total precipitated amount，i.e.，physical deposition is the main way of sulfur deposition，so as the deposition theory of element sulfur is further improved，the solid foundation of recognizing and solving element sulfur deposition in the process of developing the gas reservoirs with high sulfur content and reasonably and effectively developing the reservoirs with high sulfur content is placed.
    RESEARCH ON BOTTOM WATER DRIVE IN CARBONATE MATRIX BLOCK
    XU Ting ZHANG Xue-hong TAN Zhong-liang LUN Zeng-min LV Cheng-yuan
    2009, 31(5):  112-116.  DOI: 10.3863/j.issn.1674-5086.2009.05.024
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    The capillary flow equation of oil-wet carbonate rock block is set up，and the influence of block height，oil viscosity，rock surface wettability and the size of pore and throat on recovery under the condition of different bottom water drive rate is discussed.Block height influences recovery differently due to the different wet ability.To water-wet block，the lower the height is，the greater the recovery is，to oil-wet block，the higher the block height is，the greater the recovery is.As the increase of bottom water drive rate，water breaks through quickly along the big fractures.The factors influencing matrix block recovery can not change the fact that a large amount of remaining oil is left in the pore and throat space.
    EFFECTS OF CELL SURFACE-HYDROPHOBICITIES ON MIGRATION AND ADHENSION OF OIL RECOVERING MICROBE
    LIU Yang LI Wei SHAN Hou-fei WANG Rui
    2009, 31(5):  117-120.  DOI: 10.3863/j.issn.1674-5086.2009.05.025
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    Microorganisms in oil reservoir can enhance oil recovery by moving to crude oil and adhensing to the surface of rocks.Cell-surface hydrophobicity plays an important role in the course of movement and adhension.Five strains，named DQ11-2，1507，HX，QF，CU，which can grow with oil as the sole carbon source，are isolated and purified from the produced liquids in oilfield.The method of microorganism adhering to hydrocarbon （MATH） is used to study the bacteria Cell-surface hydrophobicity of the strains and environmental influence factors.The result shows hydrophobicity changes with the difference of cultivation time，carbon source，temperature and pH value.The cell-surface hydrophobicity of bacteria is increased by the addition of certain amount of Lipopeptide Biosurfactant.
    DISCUSSION ON DELIVERABILITY FORMULAS OF HORIZONTAL GAS WELL
    CUI Li-ping HE Shun-li NING Bo
    2009, 31(5):  121-124.  DOI: 10.3863/j.issn.1674-5086.2009.05.026
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    As more and more horizontal wells are drilled in gas reservoirs，determination of accurate deliverability formulas is of great significance.Because deliverability formulas of horizontal oil wells cannot be directly used for horizontal gas wells，after introducing research progress of horizontal well′s deliverability formulas，deliverability formulas of horizontal gas wells are obtained from improving the deliverability formulas of horizontal oil wells by using the method proposed by CHEN Zhi-hai etc.Through comparing the results of these formulas，Borisov，Renard，Dupuy，LANG Zhao-xin and CHEN Yuan-qian formulas are of higher precision than Giger，Joshi formulas which are widely used in horizontal oil wells.It is of reference for future deliverability study of horizontal gas wells.
    油气化学工程与化工
    EXPERIMENTAL EVALUATION ON FORMATE BASED DRILLING FLUIDS FOR GAS HYDRATE DRILLING IN OCEAN WATER
    JIANG Guo-sheng NING Fu-long ZHANG Hao TU Yun-zhong ZHANG Ling
    2009, 31(5):  125-129.  DOI: 10.3863/j.issn.1674-5086.2009.05.027
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    The hydrate inhibition and low-temperature stability of formate based drilling fluids，as well as effect of hydrates inhibitors on the fluids，are evaluated elementarily by the experimental test.The results show that a basic system（base liquid）of formate based drilling fluids，which are composed of seawater，3.0% HCOONa，3.0%SK-2，0.2%KPAM，0.1%LV-PAC，2.0%SMP-2 and 0.3% modified starch，has a good performance stability under low temperature environment （-5℃~20℃）.Adding NaCl and KCl，thermodynamic inhibitors，has little effect on the rheology properties of the basic system，while PVP （K30），a dynamic inhibitor，has a great effect on the properties.The basic system has a low ability of hydrates inhibition when it is used in deep water over 1400m.Low dosage of PVP （K30） can increasingly improve the hydrate inhibition of the basic system，and the suitable concentration is about 0.5%.Therefore，the formate based drilling fluids which contain high concentration of salts and low dosage of hydrate inhibitors can meet the needs of gas hydrate drilling in the deep water.
    SIMULATION OF MEMBRANE BASE ABSORPTION FOR REMOVING H2S IN NATURAL GAS
    ZHAO Hui-Jun XING Xian-feng ZHAO Shu-hua GONG Ji-hui
    2009, 31(5):  130-134.  DOI: 10.3863/j.issn.1674-5086.2009.05.028
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    A comprehensive model of differential equation and resistance equation is established，by using MDEA （N-methyl diethanolamine） aqueous solution as absorbent and selecting hydrophobic polyacrylic hollow fiber membrane （HFPPM） as a contactor.The model is used to simulate absorption H2S mass transfer process.By using polypropylene hollow fiber membrane as a contactor and MDEA solution as the absorbent，natural gas desulfurization experiment is carried out，and the experimental data is compared with the simulated value.The results show that H2S concentration of module export gas is viewed as a measure，in the low gas-speed and low liquid-speed，the simulated value is in good accordance with the experimental data；in high gas-speed and low liquid-speed，the experimental data is higher than the simulated value but there is only little difference.So the model can simulate a very good film-absorption H2S removal process.
    INFLUENCE OF POLYMER ON OIL DISPLACEMENT EFFICIENCY OF PETROLEUM SULFONATES SYSTEM
    LI Yang;DUAN You-zhi
    2009, 31(5):  135-138.  DOI: 10.3863/j.issn.1674-5086.2009.05.029
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    The effect of polymer，such as partially hydrolyzed polyacrylamide，on the dynamic and equilibrium interfacial tension of petroleum sulfonates and oil/water systems is examined.It is testified that polymer added in a certain concentration scope in the system only prolongs the time which the system needs to reach at the equilibrium interfacial tension，but the ability of the system for washing oil is not influenced.The simulation test by changing the injection sequence or injection mode of polymer and petroleum sulfonate indicates that the maximum oil displacement efficiency is acquired by the injection mode in which the petroleum sulfonate solution is injected after polymer flooding.The main reason is the decrease of adsorption site on the surface of rock for the adsorption of partially hydrolyzed polyacrylamide by hydrogen bond and the reduction of association body formed by polar group，so the loss of petroleum sulfonate in the core is decreased，as a result，the oil displacement efficiency of petroleum sulfonate for enhanced oil recovery is relatively increased.
    THE FUNCTION AND APPLICATION OF OIL SOLUBLE TEMPORARY PLUGGING AGENT YRC-1
    CHEN Xu-qing;HU Shou-zhi
    2009, 31(5):  139-142.  DOI: 10.3863/j.issn.1674-5086.2009.05.030
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    There are two constraints for a temporary plugging agent.One is the diverting effect，the other is oil-soluble，the oil soluble，acid soluble and suspension stability of the YRC-1.A new oil soluble temporary plugging agent is studied，and the influence of different factors on the temporary slugging rate and plug removal rate of the YRC-1 is investigated with the core flow experiment.At last，the YRC-1 is applied in oil field.The results show that，the YRC-1 has good oil-soluble and acid insoluble properties，better suspension stability and good diverting effect.In addition，the YRC-1 has many advantages such as high temporary slugging rate，releasing temporary，slugging automatically after operation and operating easily in-situ.
    LABORATORY STUDY ON XN-P HIGH CAPACITY CHANNEL BLOCK AGENT
    XU Wei-dong LI Ke-xing PU Wan-fen ZHAO Ji
    2009, 31(5):  143-146.  DOI: 10.3863/j.issn.1674-5086.2009.05.03
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    The existence of high capacity channels in unconsolidated sand stone reservoir leads to the block agent fluid leaking easily.Using low PAM and crosslinker under the condition of 80℃ generates a block agent which can be used in high capacity channel water shutoff.The block agent consists of 1.0%~3.5%PAM and 0.8%~1.4% cross linker.Through the lab experiment，the influence of PAM concentration，crosslinker concentration，temperature and formation water salinity on gel strength and gel forming time are studied.By single core flow experiment，the shut off capacity of block agent is studied.This kind of block agent which needs 8~72h to form gel，has no alternation by seal packaged in 80℃ oven after 7 months.In high capacity channels or super high permeable formations（14644×10-3靘2），the resistance coefficient is 20.8 and the gel has the strength of 27.93MPa/m and the efficiency of water shutoff access to 93.2%.It has the advantages of controllable gel forming time，high strength，well stability，and can meet the need of unconsolidated sand stone reservoir water shutoff.
    RESEARCH ON THE FLOCCULENT FOR THE CALCIUM-MAGNESIUM PRECIPITATION OF THE GASFIELD BITTERN IN THE MIDDLE SICHUAN
    LIU Chang-kun LI Chun-fu ZHU Shan-shan ZHAO Hai-jie
    2009, 31(5):  147-149.  DOI: 10.3863/j.issn.1674-5086.2009.05.032
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    Extracting salt is an effective method to comprehensively utilize brine from gas field，but high concentration of Ca2+ and Mg2+ can bring about inorganic scale，which can be removed by precipitation.In this course，the flocculent plays an important role.In this paper，the effect of flocculent on the properties of the calcium magnesium precipitation is studied.The result shows a anionic polyacrylamide （APAM） can be selected as the flocculent for the precipitation with the shortest settlement time and the lowest water turbidity under the condition of the temperature of 25℃ and the stirring speed of 500r/min and the flocculent amount of 50mg/L.
    EXPERIMENTAL RESEARCH ON ACTIVE ALKALI-POLYMER COMBINATION FLOODING SYSTEM WITH PRODUCED WATER
    YANG Huai-jun YANG De-hua PAN Hong YU Di ZHANG Jie
    2009, 31(5):  150-154.  DOI: 10.3863/j.issn.1674-5086.2009.05.033
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    In the field testing process of alkali-polymer combination flooding，the alkali compounding with produced water or formation water appears unmatched，which brings about the crustation of ground pipeline and performance descent of the displacement system.Under the reservoir condition of upper Ng groupⅡ，Yangsanmu Block 3，Dagang Oilfield，alkali-polymer combination flooding dissolved with produced water is investigated.The matching of active alkali with produced water is better than the sodium carbonate.The interface tension is two order lower than that of sodium carbonate solution/crude oil and IFT reaches 10-3 mN/m，the ability of resistance calcium and magnesium ions is about 500mg/L.The emulsification of active alkali and the crude oil is strong.Four kinds of polymer and the alkali have tested for the compatibility in alkali-polymer combination flooding system.The polymer HTPW-111 is better matched with alkali and salt-resisting.Active alkali-polymer combination flooding system with produced water still keeps the property of increasing viscosity action and reducing oil/water interfacial tension of polymer flooding.
    STUDYING ON THE SIMUTANEOUS DETERMINATION METHOD OF CHEMICAL AGENT CONCENTRATION IN COMPOUND FLOODING
    TANG Xiao-yan ZHANG Bo-xin LIU Zhi-di WANG Xiao-guang
    2009, 31(5):  155-157.  DOI: 10.3863/j.issn.1674-5086.2009.05.034
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    In view of the fact that the components of compound flooding are complex，at present，it is difficult to simultaneously determine any component concentration by using analytic method of single component sample，the derivative spectrographic method is proposed.By using this method，the concentration of KY，XCC and AOS in the compound system are determined，and its accuracy and the major influencing factor are probed.The experimental result indicates that the concentration of KY，XCC and AOS are separately in 2～100mg/L，3～60mg/L and 2～100mg/L，the corresponding wave length separately in 229.5，208.5，235.5nm.Its derivative spectrum obeys the Bill law，and three extinctions have the very good additive property.The obtained data are analysed by the least squares method，thus the concentration of three kinds of chemical agents is separately determined.Without being separated and depurated，the multi-component solution concentration can be determined simultaneously and accurately.One new technical method is proposed to simultaneously determine the multi-component solution concentration.
    石油机械工程及其它
    AN ALGEBRAIC METHOD OF BOREHOLE TRAJECTORY DESIGN WITH DEFINED BOREHOLE DIRECTION
    LU Gang
    2009, 31(5):  158-162.  DOI: 10.3863/j.issn.1674-5086.2009.05.035
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    The borehole trajectory design to be drilled well with defined direction needs to solve a set of 7-element nonlinear equations.To the generally used numerical iterative process，there are many intrinsic disadvantages.A new method，algebraic method，is presented to simplify the primitive equations into a set of 3-element polynomial equations，and is further resolved into solving all the positive real numbers of a 10-degree polynomial equation and a set of 2-element linear algebraic equations.The computer realization of algebraic method is provided.It is fast in computation speed and requires little memory.The algebraic method has similar mathematical nature with analytical method，and can give judgment for whether a problem has solution and correctly solving all the solutions when a problem has multiple solutions.The method can be applied to solve the problems in trajectory design of directional and horizontal wells，thereby its theoretical importance and application future are proved.
    THE RESEARCH ON MOTION CHARACTERISTICS OF TRIPLEX SINGLE-FUNCTION RECIPROCATING PUMP DRIVEN BY LINEAR MOTORS
    HOU Yong-jun LI Bei-bei ZHANG Pei-zhi LENG Xi LI Gang
    2009, 31(5):  163-166. 
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    In accordance with the disadvantages of traditional triplex single-function reciprocating pump，such as the big fluctuating limit of discharge and pressure and the difficulty to adjust discharge and so on，a kind of triplex single-function reciprocating pump driven by linear motors is put forward.The operating principle of this reciprocating pump is introduced，the motion characteristics and phase is brought forward，which can achieve “constant discharge rate”，the influence of motion phase error on fluctuating limit of discharge is discussed.The research results show，based on the given motion characteristics and phase，the main influencing factors of fluctuating limit of discharge are the length of stroke of pump and accuracy of its controlling system，the higher the accuracy is and the longer the length of stroke is，the lower the fluctuating limit of discharge is.Calculating example shows，without air chamber，triplex single-function reciprocating pump driven by linear motors can achieve the fluctuating limit of discharge of crank-sliding block triplex single-function reciprocating pump with air chamber.The research results provide the theoretical fundamental for developing new style “constant discharge rate” reciprocating pump and designing its controlling system.
    THE COST OPTIMIZATION OF THE REFINED OIL SECONDARY TRANSPORTATION BASED ON THE SHORTAGE CONDITIONS
    YU Xiao-zhong;LIU Hong-yuan;CHEN Jian-sheng
    2009, 31(5):  167-170.  DOI: 10.3863/j.issn.1674-5086.2009.05.037
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    In the marketing environment of refined oil shortage，the oil products sale enterprises carry out the scientific and rational selection of distribution and optimization of transportation costs for gas stations，which is one of the effective ways to cut marketing costs and reduce profit loss.In this paper，with the goal of the secondary transportation costs in the logistics and distribution of refined oil，the transportation cost optimization model is established under the conditions of a shortage of refined oil，and the process of optimization of the model and calculation method offered with transportation planning principle.A large municipal oil sale company is taken as example，the model is used，the gas stations under the conditions of shortage of refined oil in the limited constraints based on different circumstances discussed，and the sensitivity analysis of transportation costs conducted.The research results show that the transportation costs of refined oil increase with the minimum requirement limit increases in the gas stations，by changing the constraining parameters of the model and programming calculating software，the model can be extensively applied.
    MICROSTRUCTURE AND SEAWATER CORROSION TO WELDING JOINT OF X70 PIPELINE STEEL
    FAN Zhoua LIU Jian-yib LI Shi-lunb ZHANG Tian-jiang
    2009, 31(5):  171-174.  DOI: 10.3863/j.issn.1674-5086.2009.05.038
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    The welding joint of X70 pipeline steel under certain practical welding process is studied.The microstructure of welding base metal，welding seam and HAZ of X70 pipeline steel are analyzed with microscope and elec-chemistry，the polarization curves and corrosion rate of different welding joint zones are tested in order to study the corrosion resistance property.The results show that the microstructure of different zones of welding joint is uneven，and there are obvious difference in corrosion rate and electrochemical behavior，corrosion potential and rate of different zones of welding joint change during the process of corrosion，and couple corrosion is formed between HAZ and welding base metal，at the same time，welding joint mainly exists spot corrosion.
    MODE ANALYSIS ON BENT SHAFT OF FIVE-PLUNGER-PISTON WATER INJECTION PUMP
    ZHU Xiao-hua DENG Fu-cheng TENG Zhao-feng ZHAO Hong-chao WEI Gang
    2009, 31(5):  175-177.  DOI: 10.3863/j.issn.1674-5086.2009.05.039
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    Bend shaft is the main drive part，its mode character impacts the pump′s mechanical behavior and efficiency.Based on the finite element method and modern CAE software，the authors of this paper calculate top 30 natural frequency of a five-piston injection pump bend shaft′s and analyze its mode characteristics，some mode shapes are presented.By calculating，it is found that the bent shaft natural frequency is intensive at low-level frequency segment，there are only two available frequency interval，the current excitation frequency is in the mode frequency interval[15，16]，the other available frequency interval is fixed frequency interval[23，24].These two available frequency intervals do not meet engineering standards commendably.So input speed fluctuations and output load fluctuations should be strictly controlled when injection pump works to avoid sympathetic vibration，which can lead to internal component failure.
    博导论评
    MODEL OF TWO-LAYERED RESERVOIR WITH CROSSFLOW AND DUAL POROSITY MEDIA
    ZHANG Lie-hui WANG Hai-tao JIA Yong-lu LIU Yang
    2009, 31(5):  178-182.  DOI: 10.3863/j.issn.1674-5086.2009.05.040
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    On the basis of Bourdet′s research on the reservoir model with single porosity and two layers and Warrant-Root′s research on the reservoir model with single layer and dual-porosity，aiming at the present study focusing on homogeneous reservoirs and the research on layered reservoirs with dual- porosity media being neglected，the authors of the paper analyze the complex flow mechanism of two- layered reservoirs with dual- porosity media and interface crossflow，through strict and detailed derivation，the flow model of this types of reservoirs is firstly built up，and the model is solved.By means of Stehfest numerical inversion and computer programming，the typical curves of bottom hole flow pressure are plotted.Finally，the influence of formation parameters on curve shape is analyzed according to flow mechanism and process.The achieved conclusion will be helpful to correctly recognize the flow mechanism of the reservoirs，and can be used to analyze well testing and reservoir deliverability.
    探讨与争鸣
    NET STRESS CAN NOT BE USED TO EVALUATE THE STRESS SENSITIVITY IN THE LOW-PERMEABILITY SANDSTONE
    LI Min XIAO Wen-lian ZHAO Chun-lan ZHENG Ling-li LI Li-jun
    2009, 31(5):  183-186.  DOI: 10.3863/j.issn.1674-5086.2009.05.041
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    Theoretical study shows the net stress is not equal to the effective stress because of the existing microcracks in the low permeability sandstone.In order to demonstrate the relationship between net stress and effective stress，laboratory work is performed in this study.The experiment includes the aging treatment and four times test on decreasing inner pressure at different confining-stress.The permeability data at all pressure points in the process of decreasing inner pressure is obtained with the steady-state method.The results show that permeability is different for the equivalent net stress in the different confining-stress，which implies net stress cannot take the place of effective stress to evaluate the stress sensitivity.At low confining stress，the variation range of permeability is wider，while at high confining stress，it is narrower.In the end，the stress sensitivity evaluation on permeability is done and the results show that the stress sensitivity is moderate sensibility for the studied tight sandstone reservoir.