Eight samples with different lithologic characters are collected from sandstone-conglom-erate reservoirs with positive rhythm. Under five kinds of saturation fully saturated states-with water( S _w=100%),oil( S _o=100%),gas( S _g=100%),irreducible water and residual oil,the velocities of compressional and shear waves(V _p,V _s)and mechanical pararneters(Bulkmodulus K, Young's modulus E, Lame constant λ, Rigidity modulus μ, Poisson's ratio v andDensity ρ)are measured precisely under different effective overburden pressure in laboratory. The results of this study suggest that:(1)Elastic moduli E,K,λ,μ of rock increase as pres-sure ΔP increases,variation of E,K,λ,μ with ΔP is more sensitive in low-pressure rangethan in high pressure range. (2)Under the same saturation state,the range of elastic modulivs. effective overburden pressure curves is controlled by lithological variations in the samereservoir. (3)Under the same pressure(surface to subsurface)and in three systems(oil-water,oil-gas,gas-water),elastic modulus in each case is a linear function of saturation. (4)Elasticmodulus vs. pressure curves have evident zonal distribution under different saturation state. (5) There is a good correlative relationship between the dynamic and static compressibilitycoefficient in eight samples.

The eastern part region of Qidam basin is a Quaternary depositional and subsidence center being large and extensively distributed.The development of contemporaneously depositional structures developrnent is small in range. This region is favorable area for gas generation, migration and accumulation. The gas bearing formation is younger and shallow,thethickness is big,the structures conditions are sirnple,and the gas reservoir has. a unique andtypical feature. Tainan gas field is a prolific gas field discovered in recent years with typicalfeature and is a large one. This paper analyzes the geological and geophysical feature of gasreservoir from structure morphological feature,sedirnentary facies model,gas reservoir typeand abnormal information in gas-containing etc. demonstrates the relations between the special geological texture and unique seismic abnormal;analyzed the high production rate andabundance factors of gas fields. It is important to both optimum exploration and developmentprogram, and also gives some reference for areas with similar seismic and geological conditions.

Fractured reservoir is a main type of Ordovician limestone reservoir in Lunnan region of Tarim basin, northwestern China. The reservoir is characterized by low matrix porosity(about 1%),abundant fractures and some solution vugs. According to comprehensive analysis of electrolog(dual laterlog and microresistivity log),high resolution dipmeter tool(HDT), sonic log(sonic wavetrain anomalies),compensation density log and other well-logging data,combined with core analysis and formation testing data,we proposed an effecient method forevaluation of fractured limestone reservoir,i.e. a comprehensive fracture probability method,by which we study and evaluate the Ordovician reservoirs in this working region.According to detection of conductivity anomalies,formation microscanner,and borehole sonic televisionlog fracture orientation of Ordovician reservoir in the working region were detected and thedevelopment of fractures was studied with the use of con1prehensive fracture probabilitymethod and structural stress analysis. Petroleum exploration showed that the method proposed is efficient and results of reservoir evaluation are significant to oil exploration and development in the working region.

The distributary channel sand bodies in shallow water delta are one type of particularand irnportant reservoir rock.They are characterized by the following aspects:(1)Vertical sequence types varied and thickness of sand bodies changed a lot.(2) Sandstone thickness,porosity and permeability of a reservoir are distributed in a shape of belt or beanpod in sandmernber scale. (3)Sand bodies are occured randomly is space, which are controlled by pale-ogrogeaphy,tectonic structure and energy of flow. (4)Distributarv channel sand bodies compose labyrinth reservoir geological models,which may divided into equal thickness and very unequal thickness reservoir geological models.(5)It is rather difficult to develop this kind ofreservoir,well pattern locations must be reasonable.

The geological reservoir model is considered as a highly generalization of the characteristics of the studied reservoirs. With reservoir descriptions in the Zaovuan oilfield and someother oil fields the authors postulated the four scales of geological reservoir models in whichthe reservoir types,reservoir geometry,reservoir parameters,fluid property,and pore structures were quantitatively described both macroscopically and microscopically.Such geologicalreservoir models can be an effective reflection of the conditions of reservoir formation andregularity of hydrocarbon accumulation. It plays a predictive role for exploration and development ol a new area.

A comprehensive analysis system of fractured reservoir is a compound system analyzing andevaluating reservoirs,which is built on the basis of petroleum geology of the reservoir,selectand use the elements of geology,geophysics,petroleum reservoir engineering etc.,by meansof a series of methods of geochemistry,rock mechanics, finite-element method,finite-difference method,hydrocarbon inclusion,n1ulti-element statistics and computer technology…etc. This system include five subsystems:the detecting of the fractured core,the analyzing of thefractured distribution,the analyzing of geophysics,the analyzing the hydrocarbon and thereservoir management system.

It is a difficult problem in oil and gas exploration to predict formtion pressure before drilling quantitatively. Easy and dependable method has long been a target for oilman to seekfor. Liaodong Gulf is studied as a main object to predict formation pressure quantitativelybefore drilling with seismic instantaneous velocity curve regional compaction model and velocity of sound wave equivalent compaction method are used along with personal experienceto determine formation pressure by the method of time difference of acoustic wave. A satisfactory result has been obtained.This method is simple,convenient and dependable. It givesfavorable effects for safe drilling,reducing costs,increasing economic benefit and predictingoutput,and is helpful in studying the regional abnormal pressure and its relations to oil andaccumulation.

Black liquoris the waste water produced from alkaline papermaking mills. It behaves like a latent alkaline. Black liquor system is a combination of black liquor,surfactant polymercan be used as an oil displacement agent in a combination flooding. According to the conditions of Xinjiang pilot area,the optimum formula(formula 2-3) of black liquor system hasbeen ohtained by an analysis of the increment chorograms of recovery efficiency in the pseu-dotricomponent phase diagram. Main mechanisms in such a displacement include low interfacial tension,emulsification-entrainment, emulsification-entraprnent,spontaneous emulsification,reduction of water wettability,and softening of rigid membrane etc. Enhanced oil recovery of black liquor system have been confirmed by a combination of the study of variouschorograms of black liquor system with analysis of effluents of oil displacement and a directobservation of oil displacement in microscopic model.

In the history of water displacement curve studies,there are two kinds of methods usedup to date. One is to discuss the relations of cumulative production,cumulative water production and cumulative fluid production. The other is to discuss the relations between watercut and recovery of recoverable reserves. This later relation can be used to study differentwater cut changing pattern,various types of convex,concave and S curve on the carnationcoordinate svstem in which the recovery of recoverable reserves as obvious and the water cutas ordinate are discussed.There must exist some relations between water displacement curveand the water cut and recovery of recoverable reserves curve,but the former can only revealone type of the later curve. We define the generalized water displacement curve as:a waterdisplacement curve formula which can express many type of curves of the water cut and recovery relations simultaneously. This paper proposed a new generalized water displacementcurve formula, discusses its forms and characters.It concludes that:the direction of waterdisplacement curve research should search a rnore simple,more precise and more practicalgeneralized water drive curve formula.

A total of 28 condensate oil and gas reservoifs have been found in Bangqiao oil and gasfield.The area and reserves of these reservoirs are small. Among them, 27 condensate gasreservoirs have already been recovered by depletion. Up to Dec. 1990, 15 gas reservoirs havelost their productivity. Through analyzing and studying the whole process of the oil and gasreservoir development, all the characteristics have been understood,thus,the factors whichaffect oil and gas recovery efficiency have also been studied.Numerical simulation and technology of unloading gas well are used to give preliminary ways to improve the oil and gas recovery efficiency.

Based on information of cumulative production which is a function of time and studywith statistical data, a new model for the prediction of the production rate, cumulative produced rate, recoverable reserves, max. production rate and the time when it occurs is established. It is demonstrated in this paper that the well known Gomperts prediction model canbe obtained by a simplification of this prediction model.

Using microorganisms in-situ fermentation to enhance oil recovery is a new technologyin the petroleum industry. This paper discusses the screening and evaluation of bacterialspecies both in the laboratory and in a pilot test in Daqing oilfield. The bacteria used are Pseuodomonas aeruginosa,Xanthemonas compestris,Bacillus licheniforms and 5GA,which is most likely to be Bacteroikes.Oil recovery in the laboratorytests were increased by 34.3%, and the residual oil recovery increase was 69.8%.Ahuff-and-puff pilot test on two wells, Dong 6-J22 and Dong 5-J18,which are located in the heavyoil zones in the oil-water transitional zone of eastern Daqing was run in June-July,1990.After the two wells were shut in for 40 and 64 days,respectively the pressure in the tubingand casing of Well Dong 6-J22 had increased by 1.6MPa and 1.9MPa,respectively. Alsodaily liquid production was increased by 15-20t/d,water cut decreased from 94% to 84%,and oil production increased from 3t/d-5-6t/d and lasted about 8 months. After Well Dong5-J18 was shut in for 64 days,liquid production increased,oil production increased from 7.6Vd to 10-11t/d, and gas production increased from 234 m ¹/d to 547 m ¹/d and lasted about18 months.

A new numerical inversion of the Laplace transform(Crump's method) is presented.This method is applied in modern well testing analysis. Crump' s method, Stehfest'smethod and exact solution are compared in examples cited. The results show that Crump'smethod is more accurate and stable. The type-curves derived by this method are more exactthan those derived by Gringarten et al.

There are many factors influencing the choice of artificial lift methods,most of which aredifficult to describe quantitatively. The artificial lift methods in China oil fields are generallychosen by qualitative analysis or analogy. All factors affecting the choice of artificial liftmethods are considered, a general model for optimizing the lift methods are established.Through a large amount of investigations,the matrixes of weight factor and attaching extentare set up by the statistical method.A computer program is complied,the results of its application indicate a quite good consistency with practice.

"Compound crown wheel" long-stroke pumping unit is a type of high speed rod pumpingunit,which is designed for a large pump output,(200 m/d3)smaller pump diameter lessthan 70mm rod pump.So that,the annulus test can be conducted in the course of production. In this paper,design criterion presented is based on analyzing the type of some pumpingunits applied in oil field and relations between acceleration and various parameters.A newpumping unit was developed. Its maximum velocity V _m is 44% higher than the recommendation for V _m of pumping units and its maximum acceleration a _m is in a range commonly used byconventional pumping unit.

A finite element model of the drillstring in thedirectional orhorizontal wellbores is presented.The total deformation of the drillstring is divided as deformation related to the axis ofthe wellbore and the initial deformation forced by a curved wellbore.Then the non-linearproblem of the drillstring is sirnplified. The force and deformation along the whole drillstringare computed in a horizontal well with this model. The hook load as well as the contact statebetween the dirllstring and well wall can be obtained. The non-linear analysis of BHAS aredone,their results are compared with the linear results. The results in a whole drillstring areconlpared with those computed in terrns of the length of BHA. Also, the frictional analysisbased on the static analysis of the drillstring is improved due to a consideration of the contactbetween the drillstring and well wall. First computation about the force and deformation ofthe whole drillstring is d0ne. These examples show that the conclusion is reasonable. A newmethod is provided for mechanical analysis of the whole drillstring or BHA. The method pre-sented in the paper is adaptable to the analysis of casing strings also.

water loss,permeability of mud cake,day particle size distribution and adsorption ofmodified starch on clay were tested in lab. With the help of infrared spectrum and X-raydiffraction, the adsorption bonding characteristics of modified starch in drilling muds wasstudied by a combination of conventional mud tests and modern analyses techniques.

The corrosion and its mechanism in Daqing natural gas processing units were fully investigated.According to the analysis of corrosion mechanism and test data,optimum preventionmeasures was put forward.The combined methods of magnesium sacrifical anode and zinc-rich paint was used to protect the corrosion by water and inhibitor was used to protect thegaseous corrosion respectively. Research results showed that the corrosion prevention behavior of the method was quite obvious for natural gas coolers of the unit.

A new approach of the geometrical layout of oil and gas gathering pipelines is presented.First,the shortest geometrical layout of gas-gathering pipelines can be determined by adding Steiner poirits beyond the wells and stations with SI algorithm without considering the topo-graphical constraints. Then the layout can be changed to satisfy topographical constraints,oron the basis of the results some options can be set up and the final layout determined by using the critical path method.

The formation and distribution of heavy oil pools in Erlian basin are controlled by the framework and evolution of a depression,underwater system,maturity of source rocks,andpetroleum migration history.There are two genetic types of heavy oils:primary and secondbiodegraded heavy oils with different forrnation mechanisms and geochemical features. Thegeochemical analysis of crude oil shows that Menggulin heavy oil pool is a primary heavy oilpool,and the heavy oil pools in the Jirgalangtu depression are biodegraded heavy oil poolswith low maturity. The relationship of reservoir petrophysics and oil saturation of the heavyoil pools in the Jirgalangtu depression indicates that they were forrned first and then thickened,and this will affect their recovery.

Well Kunan No.1 just located on the transitive region between the margin of easterncarbonate platform of Tarirn massif and Tardong geosynclinal basin. From Cambrian to Or-dovician period,the sedimentary features differ from shallow-water carbonate platform anddeep-water basin. Sedimentary processes identified include deep-water original position deposit,deep-water contour-culrent deposit,gravity-flow deposit and gravity-slide deposit.Thevertical profile has experienced the evolution of the sedimentary environments of deep-waterbasin and deep-water slope from early Cambrian to Ordovician,which shows a process thatthe carbonate platform margin had been progressed(accreted)towards the basin. The orignal position deposits in deep-water and oxygen-lacking basin can form rather good sourcerocks,whicb however,have reached the over-maturity stage.The value of calculated vitrinitereflectance rate( R _o

The.behaviour of organic chemical reactions in thermalhistory of stretchedbasin weredescribed and the formulae concerned with these reactions werederived.The calculations forisomerization of C ₂₉ steranes at C ₂₀,isomerization of C ₃₂ hopanes at C ₂₂ and aromatization of C ₂₉ C-ring monoaromatic to triaromatic steroid hydrocarbons were studied. We applied thesetheories to the stretched basin in northern South China Sea,and the calculated the progressof these reactions agrees well with the data observed in the basin.

Detailed examinations of petrography,SEM,X-ray diffraction,electron microprobe,andstable isotope indicate the main diagenetic events in the reservoirs in Jiufetang forrnation,Luxi depression,Authigenetic minerals in the reservoirs are smectite,illite,illite-smectite,chlorite,kaolinite,quartz,albite,zeolite,and carbonate. Diagenetic zones can be dividablehsed on diagenetic events related to temperature. Reservoir porosity in Jiufetang formationis secondary in origin and mainly distributed in the shallow diagenetic zone. Two diageneticmodels regarding the forlnation and distribution of secondary porosity include:(a)the forma-tion of secondary porosity relative to meteoric burial diagenesis;(b)the formation of sec-ondary porosity associated with dehydration and transformation of clay minerals.

Thspaper presentes the applications of nurnerical simulation to the study of neutron logging data. It includes calculations of both depth of investigation and enviromental corrections charts for lithology,borehole dianJleter,salinity and so on,and particularly on the effect of formation temperature(well temperature correction)which is very difficult to simulate byusing actual calibration wells. Comparing calculated results with measured results,it is foundthat the agreement is quite good.

Nonlinear mapping analysis is a mathematical method of "geometric diagram with descended dimensions",The geomatric diagram is transformed from the muitidirnensional spaceinto a lower dirnensional space by nonlinear transform,so as to directly perceive the relationship of the samples in the low dimensional space.Every factor effecting the sealitig ability of fault is regarded as one dirnensional coordinate in the multidimensional space,every fault is a point in the multidimensional space. If thesealing abilities are similar,the positions of the faults in the space are close one another.After nonlinear mapping analysis,on the conditions of keeping approximately the geometric relationship among the faults,the rnultidimensional space can be transformed into a plane. Thesimilar faults in sealing ability are close on the plane.The faults with sealing abilities known and unknown are simultaneously analysed according to the positions of the evaluated faults on the plane,the sealing abilities of the faultsmay be accurately evaluated.

In accordance with lithotype and its structural condition,the structural fractured hydro-carbon reservoir is clasified into four categories,including 13 types of traps,which are distributed in four types of petroliferous basins. In craton basins formed pre-Alpine phase,it isfavorable to form the structural fractured reservoirs in the region where carbonates mainlydeveloped in which the seals exist.During the Alpine phase an upper oil-bearing assemblageof the continental deposits was forrned in the subsidence inland basins of western China,inwhich the structural fractured reservoirs occur locally, while in a lower oil-bearing asserm-blage developed in the giant petroliferous basins,the structural fractured reservoirs have better prospects. In the craton-foredeep basin of central China,exploration for these reservoirs inthe lower assemblage has made a remarkable headway,but only those filled with coal-gere-nating gas occur in the upper assernblage. In the fault basins of eastern China,there are somestructural fractured reservoirs in the upper assemblage under special structural conditions.Thus,the structured fractural hvdrocarbon reservoirs are widespread.In the region associatedwith older uplift,specifically those with seal,it is an ideal place to look for gaint oil accumu-lation in the structural fractured reservoirs.

In this paper,mathematical method (conform transformation,imaging,superposition principle, equivalent flow resistance)and physical simulation(dectrolytic model)are appliedto study the stead state flow for a horizontal well with multiple bore holes. The flow patternand the formulas for calculating productivity of this horizontal well are derived. In addition,the parameters that affect the productivity of this horizontal well are studied.The resuIt ofcalculation was compared with the experimental data on electrolytic model.The comparisonindicated that the formulas derived here have a high accuracy and can be used to predict theproductivity for a horizontal well with multiple branched boreholes in a practical reservoir.

This paper presents a fact that theproduction toward a horizontal well flood approachesto a linear flow in thin reservoirs. Significant increases in flow rate and in areal sweep effi-ciency with horizontal wells are obtained.The oil production of a horizontal well of DQ YLoil field is equal to that from 2～5.5 vertical welis.A further utilization of horizontal wells is to improve oil recoveries with an improvementin drilling technology and reduce well costs is suggested.Using a combination of a horizontalwell and vertical wells can improve oil recoveries in a strongly stratified reservoir.

This paper describes a three-dimentional,three-phase,multi-component thermal and chemical simulator,which can be used to simulate the steam injection process in a horizontal well.The model dynamically incorporates wellbore hydraulics by taking into account two types of flow,that is,laminar and turbulent flows. The fully implicit wellbore equations and reservoir equations are solved with adaptive implicit formulation and an advanced numerical solution method.The grid system is very flexible,it may be cartesian,cylindrical,local grid refinement as well as bybrid grid.Using this model,a simulation study on thermal recovery of an extra-heavy oil reservoir in Liaohe oilfield with horizontal well is conducted.

Having analysed a large number of production data of Jinglou oilfield and one of its pilot-Area O Pilot,this paper demonstrates the recovery characteristics and regularities of cyclesteam stimulation for a shallow and thin heavy oil reservoir. It is found that recovery rate andrecovery percentage are high,OSR is low,oil production decline factor is high and water cutrises rapidly.This paper shows that the technique and economics are succesful for shallowand thin heavy oil reservoir with thickness larger than 5 meters if production parameters areoptioned.

Traditionally preflush by dkdine and salty water have been used in conjunction withchemical flooding for maintaining optimum state of reservoirs with high clay and high salinities.However,all preflushes tend to prolong the time as well as to increase the expenditures.We have synthesized a high molecular weight polymer,BPA which can be introduced to thechemical flooding formulation directly. This will eliminate any preflush requirement.The nature of this technique is as follows:1.increase the negative values of Zeta potential,2.complexation of muItivalent cations,3.increase interfacial activity of surfactant.The technique is superior when compared with the traditional formulation. Field experiment at Laojunmiao indcated the following:injection pressure, lowered from 14.4%-17.8%, water imbibition,increased 270%,mobility ratio increased 190%,adsorption of surfactant greatly lowered.

This paper utilizes Fair's model,taking both wellbore storage and skin effect and "humpeffect" to interprete the well testing records of a single well in a homogeneous reservoir.Laplace's transform is applied firsst, then residual theory is used,and finally integral inversetransform is performed to give a solution in the real space, This method differs from previousrnethod which gives a form of Laplace,s numerical inverse transform. Therefore, it has highaccuracy and requires a shorter time,because a concrete form of the solution are given.Thus,it improves the structural system of those solutions for well test of a single well in ahomogeneous reservoir,Finally,some actual field examples are given to illustrate the methodpresented.

This paper presents a inter pretation model of ectromagnitic pagation that is derived with mathphysical method. The new model has been confirmed by the results of experiment.Logging data is interpreted with this new model.It is shown that the model isvalid in certain range. The residual oil saturation computed with this new model is in good agreement with those from phase analysis.

The elasticplastic theories have been used to analyze the stresses and deformations ofcasing pipe under external pressure in this paper.The formulas obtained from this analysisare applicable for thin wall,medium thick wall and thick wall casing pipes. The elastic critical pressure,the elastic collapsing of the circular and elliptical casing pipes may be calculated.Examples from this analysis show that these calculated pressures are coincident with experimental results particularly, the supposition that the compression yield stress is 1.1 times the tensile yield stress used in reference papers[1.7] has been revised in this paper, Thisanalysis provides a basis for analyze stresses of casing wellpipe supported by multi-loads.

On the basis of analysing the slotted pipes available by means of the contrast experiments with liquid flow,which aim at analysing and comparing the ability for different slottedpipes to prevent sand from flowing into them,and the pressure drop of liquid through them,we develop a optimum structure and size of the slotted pipe. Taking the maximum oil production and reasonable sand production as the first objective and,the lowest cost of the slottedpipe per meter as the second objective,we use two steps of computer optimized prograrn todesign a new type of composite slotted pipe. With the same condition,the pressure drawdownof liquid through the new type of pipe is 10%～20% lower than other types of slotted pipes,and sand control capacity increase by 10%.

A large number of investigation on fracture toughness andon mechanical properties forsucker rod of 35 Mn2 steel,and the reliability analyses have been made this paper.It is verified that the distribution of all parameters:σ _s,σ _b,Ψ,δ and K _1c is normal. We have also determined the point estimation and the region estimation of parametsrs for every distribution.This study provided the evidence for reliability assessment of parts and defects of sucker rod.

In order to explain the different responses of Daqing and Dagang crudes to pour pointdepressants(PPD),two commonly used PPDs,i.e. an ethylene vinyl acetate copolymer(EVA)and a polyalkylacrylate were chosen as additives and the effects of each kind if PPDon the pour point reduction of these two crudes have been studied.A specially designed pro-cedure was applied to separate from crudes the following categories of components includingasphalt,paraffin, and resin. After the structure identification and characterization by someof the methods of IR,LC,GC.GPC and elemental analysis,the individual or cross-over effect of the above mentioned components on the pour point reduction were determined with orwithout the presence of PPDs.

In this paper,annual petroleum production data of one country are analyzed and themathematical model for the petroleum production are constructed.Because the characteristicof these data have a periodicity at a quarter of a year, the periodic time sequence is transferedinto the trend time sequence of petroleum production by using the technique of data separation.Then,every sequence is predicted by multiple staged stepwise prediction method, and a high accurate prediction results of the petroleum production are obtained.

Using frozen,stress photoelastic method,stress intensity factors of internal surfacecracks in spherical shells and spherical shells with geometric defects(misalignment or angular distortion) were studied.In order to compare with the solutions of stress intensity factorsof cracks in flat plates,a new definition of internal surface crack shape in spherical shells wasproposed. In this paper,the variations of stress intensity magnification factors with crack depth tocrack length ratio,crack depth to wall thickness ratio, wall thickness to inner diameterratio, and along the crack front were analysed. Mixed mode K _Ⅰ and K _Ⅱ of misalignmentin spherical shells were discussed.The stress intensity factors of cracks in spherical shellswere compared with the solutions of that in flat plates,and an empirical formula of curvaturecorrection factor was presented.They are very useful for the safety of spherical shells.

The modern petroleum exploration system in CNPC,as a scientific engineering,was buil-upon an integrated multisubject exploration work environment,and was based on the advanc-ing of exploration theories and technologies.The engineering exploration system has scientiic,integrated,manipulatable and highly beneficial properties.