By analysing and studying the theoretical basis and method of integrating well-logging with seismic data,this paper proposes a new eyuatian for hydrocarbon correction of acoustic and density log data in the invasion zone and a new method for extracting wavelet and deconvolution factor. The theory and technique proposed by the authors was used in description of Wendong reservoir,Zhong yuan oilfield,to enhance the match of well-logging data with seismic data and improve the accuracy of the integration technique.

This paper introduces the design idea,main functions and structure of an expert system in well-log fades analysis of a complet sand-mudstone. In addition,a detailed discussion on the principle of inference its and application characteristics is presented. The system is programmed with C language &. 8086/80286 Assemble Language. On the basis of a deep study on the electric-lithologie relationship and the electric-ithofacies relationship,we apply the relevant principles to well-log fades interpretation,which gives rise to a successful system. Abundant functions,consisting mainly of pretreatment,knowledge acqmsition,fact rule management,inference,explanation and so on,are included in the system.

The Dongzhuang structure in the Nanxiang Basin,Henan anti Hubei Provinces,is an anticline associated with aft asymmetric erestal graben. Growth faults at the southeastern edge of the graben dip more gently than those at the northwestern edge. The Dongzhuang structure is hounded to the south by the Xinye-Quwa fault zone which marks the southwestern hnnndarv of the Nanyang sub-basin within the Nanxiang basin.

Daihai lake is located in central Inner Mongolia and is a modern faulted basin of terrestrial fades. This paper emphasizes the analysis and study on the depasitianal processes and the heterogeneities on different sedimentary scales of two deltas in the direction of the short axis in Daihai lake basin.One delta,Yuanzigou delta,is located in the northern steep slope of the Take basin,while the other one,Bulianghe delta in the southern gentle slope of the lake basin,Bath are fluvial-dominated braided deltuic system with coarse deposits.

Low permeability sandstone reservoirs generally are defined as oil reservoirs with a gas permeability of less than 50md,in China. They can be further graded into three types based on values of permeability and development scheme. Accrading to their geological occurrence,low permeability sandstone reservoirs in China can be classified into three categories:primary low permeability reservoirs,secondary low permeability reservoirs and fractured low permeability reservoirs. Reservoir description and evaluation would lie different in different types of low permeability sandstone reservoirs.

The crust of east China has been affected by extensional stress since the Mesozoic-Ceno-zoic. Ectensional structures developed widely in the Jiyang depression and its surroundings.After analysing outcrop sections and seismic profiles,we can sum up the characteristics of extensional strucyures and construct a geometric model of extensional structures in the studyarea. Not only can a series of parameters related to extensional activities be acquired,but alsocan the restored sturctural sections in different geological ages be obtained by using thd basicmethod of balanced-section based on the model,In terms of the calculation of two profiles inthe Yangxin sag of the Jiyang depression,the analysis results ane:the last rifting stage ofthe sag began form the second member of thd Kongdian lormation,the rifting actibity wasstrongest during the first member of the Kongdian formation and the lower part of the foruthmember of the Shahejie formation,tended to relax form the upper part of thd fourth memberof the Shahejie formation,and became much weaker in the second member of the Shahejieformation and thd Dongying formation which were thd transition stage form riftiong to sub-siding.

In has been verified by tracer test that there are channels in some reservoirs.Clay as aprofile control agent in single-fluid method has been studied and used by some foreign engi-neers,but no clay as profile control agent in double-fluid method has been studied so far.This paper deals with this project in which selection of clay,diameter of clay grain for reten-tion in formation,formulation and mechanism of clay as profile control agent in double-fluidmethod are included. The effect of channel plugging by using clay as a profile control agent ina double-fluid method has been confirmed by field testing in Shengtuo Oilfield and Cheng-dong Oilfield.

This article gives out a method for the screening of the application of horizontal well in a non-thermally developed sand stone reservoir,General screening frame and detailed screen frame are established accordingly including:1)Types of the candidate reservoir with first priority for horizontal drilling.2)Parameter limits of candidate reservoir. 3)The features of the reservoir to be developed with vertical wells.4)Economic evaluation and fundamental formalas.

The final recovery efficiency of water drive is calculated with optimization theory and equations of displacement;In the calculation more precise values of end points of relative per-meability mersured by experments are applied,without the need to assume the ratio of relative permeability of oil and water.The result has shown that the lgwp vs recovery factor doesnot take a linear relationship when water cut reaches a certain value;Even if lgwp vs recoveryfactor is not a straight line because of stimulation treatment,the final factor can still be estimated.So the treatment can be evaluated according to the change of the ultimate recovery. At the same time the cures of relative permeability can be determined.

With a new polymer flooding simulator,simulation studies under various conditions arecarried out to study the effect of various factors(such as:the oil-water viscosity ratio,typeand degree of reservoir heterogeneity,wettability,oil density,polymer adsorption,permeability reduction,inaccessible PV,dispersion and injection rate,etc.)A lot of interesting conclu-sions are drawn. For example,polymer flooding cannot necessarily enhance oil recovery,evenif mobility ratio is unfavourable,Oil-wet is not always a factor more favourable to the polymer flooding. For a vertically reverse rhythmic reservoir,in certain case,the less the hetero-geneity,the more favourable the polymer flooding.

This paper presents a homogeneous composite reservoir model in which the wellborestorage and skin effects are included.A mathematical model describing a homogeneous com-posite reservoir is given and solved by Laplace transformation.The composite reservior type-curves are given and their characteristics are dicussed.This paper presents one field example to demonstrate the application of the type-curves toanalyze pressure transient test data.

This paper presents a micro-simulation test with the dilute-biosurfactant system in a transparent glass simulator.The results of micro-simulation tests of a-system with low inter-facial tension are onalyzed with a point of view of the fluid flow chemistry in porous media.The reaction of the system with residual oil can be considered as the combined action of ag-gregative force of activated molecule toward low interfacial energy,capillary force and driv-ing force. The forces cause a series of interfacial structures are "micro-streamline","micro-fingering","micro-meniscus"and"micro-flake-off"on oil/water interface in porous media.They reflect the micromechanism of porosity micella, solubilization,emulsification and solu-bility as well as mechanism of fluid flow in pores.

In this paper one of the pattern recognition methods,Fisher verdicts,is introduced fortreating the data of buried asphdalt coatings on pipes in the Daqing Oilfield.An extended lin-ear model and stepped verdicts are used to study the degradation of asphalt coatings. As a result,a simple expression with four variables:endurance(years);soil resistivity (Ω. m),saltcontent(%);and water content(%)is given as the criterion of coating degradation,Thecontributions of the above four variables on the classification of degradation degrees are alsoanalysed.In addition,the mathematical principles and the application methods of Fisher ver-djcts are introduced.

The multi-objective grey situational decisison method is applied to the design of oil orgas pipeline,By treating pipe material as event and design method as countermeasure,andtaking the cost of piping material and installation,the yearly converted expenses on pipeline,pipe resistance,service life of pipeline,and reliability of pipeline as decision ohectives,wemade a decision analysis on pipeline power installation,pipe material and design methods ofoil and gas pipeline,and gave a decision model in this paper.The calculation of a real example shows that 16Mn steel and the reliability grey optimum design method are an optimumdecision,if power installation is known;and there is only two options of 16Mn steel and carbon fiber composite. As far as the methods of reliability design and reiability grey optimumdesign are concerned,the grey optimum design is better.

In this paper,the fuzzy information in structural failure criterion is taken into consideration when calculating reliability degree of the structure. Also,the jumping issue of maximumstress point during Monte Carlo-sirnulation is dealt with.Based on the finite element methodand the concepts of fuzzy maximum stress set and minimum failure set,a global comprehensive formulation for calculating the system reliability degree is presented.Finally,the methoddeveloped in this paper is applied to the reliahility analysis of casinghead structure.The computational results can be taken a reference for production practice and structure design.

This paper formulates the change of dynamic parameters during cementing displacementthrough analysing and studying the dynamic process of cementing. On this basis,computersimulation and computer aided design software of a cementing process are developed.The development of the software provides a powerful supporting tool and means for making cementing design and guiding the cementing operation. Through testing and verifying in severalwells on site,the simulation and measurement results are almost identical.

Considering contact friction and curvature effect,the contact nonlinear problem of fracturing string is solved by the space beam element method and the multidirestional contact gapelement method (or agp element method).The contact state,contact reaction force and corresponding frictional resistance between the fracturing string and the bore hole wall or the in-side casing wall can be accurately described by the gap element,which allows less simplification in the mechanical model and more precise calculation of force and deformation. The calculations of field examples hane shown that the calculated hole top loads basicaily agree withfield measurement with a relative error of less than 10%.

In this paper,under the conditions of the static load and inertial load of the polished-rod of a conventional pumping unit,as well as the structural weight and inertia,we have presented on equivalent dynamic model of the pumping unit system relative to crank;meanwhile,theaccurate analytical expressions of the amplitudes and phases of the first-order and second-order synchronous waves of the balance torgue have been obtained under equilibrium conditionof overall outer forces,and the type-curves of net torque of the crankshaft with the characteristic of inertial counterbalance have been drawn.

Optimum casson parameters play a very important part in modern drilling engineering design,jet drilling and optimized drilling.This paper discusses all kinds of methods for determining casson parameters,and analyzes the advantages and disadvantages of these methods.This paper analyzes and studies from a theoretical point of view a new method for determin-ing casson parameters largely for larger dispersion data system processing-Gray systemstatic method.Its application is shown by acfual examples.

Application of carbon isotopes in natural gas by "taking the carbon isotopic ratio in ethane as a criteria to differentiate the properties of organic gas precursors and taking that in methane as a criteria to study the migration of gas in the lateral-diffusion mode" is proposed in this paper based on experimental and field data. Two kinds of natural gas originating sapropelic type of organic matter in the carbonate source-rocks in the Ordovician and from coal-bearing formation in the Carboniferous-permian respectively are differentiated mainly according to carbon isotopic ratio in ethane. The gas from the Ordovician has characteristics such as more negative carbon isotopic ratio in ethane, lower content of C ²⁺ hydrocarbons and higher concentration of hydrogen sulphide relative to the gas from the Carboniferous-permian. Qualitative identification and quantitative calculation show that the natural gas in the Ordovician reservoirs of the Central gas field is a two-component gas mixture which comes mainly from the Ordovician source rock while those from the Carboniferous is in a small quantity only. The gas which comes from the Carboniferous in the Ordovician reservoirs is found in the eastern part of the field and is associated with the erosive gulleys on the top of the Ordovician. The natural gas in the Ordovician of the central-eastern part of the basin is divided into four migration fields by using the data of carbon isotopic ratio in methane. This paper also discusses the effect of the palaeo-geomorphology,palaeo-Karst and the present structural feature on the distribution of natural gas of different origin and its migration

AVO lithologic parameters can be inverted with the help of Aki and Richards formula and the Singular Value Decomposition(SVD) method.Inversion can provide following sections:Zero-offset reflectivity section of p-wave,reflectivity section of S-wave,relative velocity sections of p-wave and S-wave, identification sections of gas sandstone. P-wave and S-wave velocities,used in reservoir prediction and detection. Synthetic sonic log can be obtainedby sampled S-wave section,a procession of the synthetic accoustic profile obtained through acombination of Zero-offset,P-wave profile and the resample reflective S-wave profile relationships between p-wave and S-wave velocities in clastic rocks,clay contents and porositiesare estimated and their sections are achieved.The paper shows the application of these sections in geological interpretations and detection of gas sandstone which have different AVO characteristics. Case study has confirmedthat the qualitative to quantitative interpretation methods are effective.

This paper develops a new method to simulate hydrocarbon expulsion,In this method,hydrocarbon expulsion from source rock is divided into two main stages according to the features and the mechanism of hydrocarbon expuision under different burial conditions.The expulsion of hydrocarbon in the first stage is mainly by means of compaction and diffusion,andin the second stage by means of microfracturing and diffusion,Therefore,this paper sets upthree hydrocarbon expulsion models,namely compaction model,microfracture model and diffusion model.The compaction model in which the compaction of source rock is considered asthe main force for primary hydrocarbon migration. Taking into account not only the decreasein pore volume of source rock during compaction but the influence of the increase in pore fluid volume resulted from clay diagenesis,hydrocarbon generation and the thermal expansion ofpore fluid as well.The microfracture model is based on the microfracturing mechanism of primary hydrocarbon migration in which hydrocarbons are expelled from source rock by the abnormally high pore fluid pressure through microfractures in a mixed phase of oil,gas and water. The main factors resulting in the abnormally highpressure compaction,clay diagenesis,hydrocarbon generation and the expansion of pore fluid are taken into account in the model.The expulsion amount of hydrocarbon through microfractures is calculated by the differenceof pore pressure and the fracture pressure of source rock.The important characteristics of theabove two models are that the equation of state and fluid phase equilibrium concept of ther-modynamics are used to determine the fluid phase behavior and saturation changes duringsource rock evolution,and hence to determine the amount of expulsion of hydrocarbons. Withthe above models,the oil expulsion history and the gas expulsion history can be simulated respectively.

Based upon the features of facies analysis,a new method using fuzzy preference ratio forquantitative sedimentary facies analysis-faszy pattern recognition is presented.Through thepreprocessing of facies markers,some numerical characteristics for facies recognition are selected,and the numerical patterns of microfacies units composing delta in lakes are established.And a case of practical application is given.

Kaifeng depression,situated in the northern part of the southern North China basin,mainly extending in NWW direction structurally and in the NNE-NE directions in some segments,is a fault-subsided Meso-Cenozoic depression. Its formation was resulted from theNWW faulting with sinistral shear-extensional movement and the NNE-NE faulting withdextral shear-extensional movement,which occurred in the late stage of the early Cretaceous,through the late stage of the Palaeocene and the Eocene.16 wells have been drilled in the depression,4 source bed systems of-O,C-P,J-K andE have been identified.Petroleum resource evaluation showed that there are geological conditions for only small-sized pools in Meso-Cenozoic,and for larger sized pools in Palaeozoic.

By using the cross-top technology of horizontal well,the goldtrace of the horizontalwell is designed just below the conformity, vertical to the strike of the reservoir formation todiscover the oil reservoir to a maximum extent and to reduce the risk of exploration to a mini-mum extent; the goldtrace of other well is designed at a direction parallel to the strike of thereservoir formation to enhance the production of a single well and enhance the recovery factorto a max. extent. According to the above principle 4 types and 5 wells: a horizontal prospecting well,a cluster rnulti-functional well,a horizontal evaluation well,a horizontal alley well,designed to examine the unconformity oil reservoir on the northeast slope of the Cheng Dongprotrusion.A set of method for the design and application of horizontal well technology in anunconformity oil reservoir is,thus,summerized to give obvious economical and serial benefits.

Group method of data handling(GMDH)was proposed by A. G. Ivakhnenko,a Russian scholar,in the 1970's.It is a method of modeling by heuristic self-organization. It can solve effectively the problem of a complex non-linear system. A brief introduction of GMDH is presented in this paper. The application of GMDH to analyze reservoir performance is alsodiscussed,and a formation pressure forecast model and production forecast model are set upby using actual data from the Nanyang oilfield.With a relative error of no more than 5%,theresult is satisfactory. Finally, the prospect of application of GMDH to oilfield developmentis discussed.

Previous studies of well testing with vertical interference assumed that a packer com-pletely seperates the producing interval into a production section and an observation section.This assumption severely restricted the use of the result of test.Because of perforation, fracturing and so on, there exists leakage behind casing for most wells. The packer may also have some problem.In this paper, a mathematical model and its interpretation method are given for a leaky vertical interference well testing in a 3-layered reservoir. The features of transient flow in the test and the influence of different parameters are discussed.The new model considers "kh" product,skin factor and storativity of each layer,crossflow between layers and leakage behind casing. It includes more parameters than the other studies.

This paper presents an alkali/surfactant/polymer combined flooding numerical simulatorwhich has considered the main displacement mechanisms(such as decreasing of interfacialtension and chemical loss,controlling of mobility,etc)and physicochemical phenomena(chemical synergytic effects,alkaline consumption, chemical dispersion and adsorption/retention in alkaline environment,reactions,variation of residual saturations and relative permeabilities,behavior of polymer solution,etc).This model has a capacity of simulation realproblems and is a powerfuI tool for mechanism study,feasibility evaluation,injection plan optimization and performance prediction for chemical combined flooding process.

The reservoir pressure is related its parameters.They are used to be determined by themethod of unsteady well testing which was time-consuming and not suitable for some flowingwells,To solve these problems, an equation of formation pressure based on dimensionless IPR curves is deduced. The equation is simple and reliable,and is of practical value. Practicalapplication will result in better economic efficiency.

Steam-foam coinjection process is applied to improve the sweeping efficiency of conventional steam drive. It promises significant recovery ot oil not recoverable by steam injectionprocess only. In this paper, a mathematical model for steamfoam coinjection processes is presentedand its numerical processing is discussed. All the mechanisms leading to surfactant losses andflow resistance of foam are taken into account. The flow resistance of foam is modelled bychanging the gas phase relative permeability and residual gas saturation in the presence offoam. The flow resistance of foam is affected by those parameters such as surfactant concentration,oil saturation, temperature, permeability,water and gas phase velocity, etc.The results of field simulation showed that the injection of foaming agent will significantly improve sweeping efficiency and oil recovery of steam drive process. The calculatingefficiency of the numerical models on a microcomputer is practical and satisfactory.

This paper gives a treatment of abnormal pressure build-up curves,incluing phase distribution in a wellbore. New series of theoretical type curves are constructed.Theoretical basis of the type curves has been established.The practical value of these type curves are demonstrated by some actual field examples.

This paper establishes a fluid dynamic equation for a reciprocating pump-piping hydraulic system with the transfer matrix method and deduces all the transfer matrixes of the subsystems.This equation reflects the fluid dynamic behaviors of the system comprehensively and practically because it considers the dynamic properties of the air-chamber and valves,the effect of different pipings and fluid pressure in hydraulic cylinders.This equation can substitutes, previous methods based on the Bernoulli equation to analyze and calculate the dynamic behavior of practical working process of the pump.

The amsotropic drilling characteristics of formation and drill bit are comprehensively expressed by equivalent equations deduced from a rock-bit interaction model. This paper pre-sents an analvsis method with which the effects on typical formation and drill bit on the well-bore trajectory may be diagrammatically illustrated. This method is easily accepted by fieldennineers.

In this paper the forces on the sucker rod string,tubing and liquid column in a sucker rodpumping system in a directional well have been comprehensively studied.A set of partial differential equations describing the movement in the pumping system has been solved by the finite difference method. This mathematical model can be applied to giving a dynamic analysis and anoptimizing diagnosis of the sucker red pumping system in a directional well.

There exists naturally an opthization problem in the reliability design of mechanical products,The optimum parameters of the products designed are found under a fixed reliability. The general method of reliability-optimization design of mechanical products is introduced with regard to the shock absorption belleville spring for petroleum machinery. A mathematical model of reliability-optimization of belleville spring is set up and an example is given.

A tbeoretical mddel of dynamic well control estabished in this paper is based on the assumption that a gas-mud two phase mixture is formed when gas flows into the well at kicking. The effects of gas slip velocity and frictional pressure drop in every flow pattern of two phase flow are taken into account.The finite difference method is used in solving mathematical equations and the algorithm of solving this numerical model is given. Two grid systems are built to overcome the difficulties in well control simulation. The effects of formation pressure, kick volume,size of annulus and pump flow rate on killing operation and on the maximum casing pressure are studied by computer simulation. Compared with experimental kill data,this model yields a closer result to actual case than that of a pumpout model.

In this paper the thermal elastic contact stress under a super-high pressure cylinder body in a perforation simulating device is carried out by the mixed-method of finite-element.The mathematical model to be used in the paper can reduce the iteration processes in calculating contact forces to the calculation of a few screwthread contact points,which may avoid the generation and solution of initial equations for many times and greatly increase the calculation speed.Also,a virtual-springs may be used to solve the singular problem of global stiffness matrix.The device has been tested with perforation explosion experiments for many times over the last two years, which shows that the results of the theoretical analysis is correct and the body may work safety and reliably.

This paper suggests a method of least square matching to smooth bout the non-Parametermodel coefficients which is directly obtained from the industrial electric furnace,and alsogives the block diagram and a comparison of application effect.

Oil and gas enrichment area in basins offshore China are controlled by rich hydrocarbongenerating Paleogene depression. Relating with large drape anticline,accompanied by largedelta sandstone reservoir or large biohermal carbonate reservoir and areal distribution of regional cap rock,large oil and gas fields could usually be formed.In continental deposit,oiland gas reservoirs are usually close to the source area.In marine sequences,if there are favorable carrier bed and areal cap rock,oil could migrate to a long distance,and can form oilreservoirs from distant source areas.Coal measure units of the Paleogene spread in a largearea offshore China with abundant coal-generating gas potential.In west of South China Seathe Paleogene marine formations are very thick with fast depositional rate,high geothermalgradient,also has favorable gas-generating capacity.

Tarim plate experienced several evolutional stages in its history:plate divergence and intraplate subducting convergence from middle Preterozoic to early Paleozoic and intraplatefolding deformation from late Paleozoic to Triassic. As a result,three types of prototypebasins were formed in the margin and in the interior of the plate. The development of theseprototype basins,together with their superimposition and refashion in subsequent time steps,provided a bulky volume of oil-bearing formations and various conditions for oil entrapment.