In spite of special background that the petroleum geology conditions are extremely complex in China and most of its Meso-Cenozoic deposits are non-marine,We have not only brought out magnificant achievements,valuable experiences in oil and gas exploration,but opened up a path for developing the oil industry ourselves.For example,oil product in China has been raised to 160 million tons at present which stands for a great oil-producting state;While in the early days of the nation's establishment,it was only 120 thousand tons.This paper is a summerization of the personal experiences and their knowledge during the career of exploration practice over 40 years which consists of the following 8 parts:The genuine learning comes from practice;Exploration is an imperative problem for the developing of oil industry,A necessary procedure must be followed in this practice;We should pay more attention to the dissecting of main faults and their secondary belts in the case of strategic disployment;We need also attach importance to overcoming the limitations and one-sidedness in the process of cognition;In order to promote offectiveness of exploration,a summedup experience during great battles for oil must be brought forth and applied illustrated with examples in the future to exploration practice based on a developed democratic style in technique disposing and centralism of collective wisdom.

The introduction of petroleum system is an important advance of petroleum geology in 90'.But its concepts and genetic clasaification widely used overseas are not applicable for analyzing the region of polycyclic movement,and factors such as multiphase pool-forming,paulopast pool-forming and vertical mixing source should be revised in this case.In this paper,a historic-genetic classification of petroleum system is put forward in view of the special feature of marine sequences in South China.In the region which has undergone polycyclic tectonic movements,it is necessary to divide petroleum systems of primary basin genetically,analyze dynamic changes after the formation evoluted,and then determine operative types of petroleum system based on regional geological characteristics.The Silurian-Carboniferous petroleum system in South China is taken as case study.

Based on the analyses by LRM of the compositions of inclusions from the typical mantle rocks in East China,it come to the following conclusions:(1)The mantle fluids contain large amount of inorganic gaseous compositions,which mainly are CO ₂,CO,N ₂,H ₂S and so on;(2)The variance of the compositions of the inclusions reflects the heterogeneity of the mantle fluid sources and the matasomatism of the mantle;(3)There are also high-content CH ₄ and H ₂ in some inclusions of the typical mantle rocks.The above facts implicate that there may exist rich carbon dioxide gas resources,hydrocarbon gas resources and other combustible gas resources in the mantle of Tancheng-Lujiang fault belt.The study in this paper has provided an important basis for the discussion of mantle fluid compositions,genesis of inorganic non-hydrocarbon gases and possibility of reservoir forming in East China.

Based on the analyses by LRM of the compositions of inclusions from the typical mantle rocks in East China,it come to the following conclusions:(1)The mantle fluids contain large amount of inorganic gaseous compositions,which mainly are CO ₂, CO, N ₂, H ₂S and so on;(2)The variance of the compositions of the inclusions reflects the heterogeneity of the mantle fluid sources and the matasomatism of the mantle;(3)There are also high-content CH ₄ and H ₂ in some inclusions of the typical mantle rocks.The above facts implicate that there may exist rich carbon dioxide gas resources,hydrocarbon gas resources and other combustible gas resources in the mantle of Tancheng-Lujiang fault belt.The study in this paper has provided an important basis for the discussion of mantle fluid compositions,genesis of inorganic non-hydrocarbon gases and possibility of reservoir forming in East China.

The identification marking of three terrigenous sequences in the upper member of Eh of Biyang fault-depression is distinct not only on seismic profile and electric log curve,but also in lithologic-geochemical features.Particularly,the lithologic-geochemical features to identify terrigenous sequence boundary include lithological types marking,clay-mineral and cement characteristics in coarse fragments,chemical constituent,C and O isotope.

In a petroliferous basin,especially a comples basin of great amplitude,often exist several fluid dynamic systems.Each system,in which oil and gas pools have similar formation conditions and comparable history,possesses relatively stable frontiers and unique pressure regime.Fluid dynamic systems can be classified into four types,i.e.,gravity-driven,compaction-driven,pressure compartmentation and no-flow systems.Different type of systems with different openness have different relative importance of hydrodynamic,thermodynamic and stress-induced forces in oil and gas pools formation.In oil and gas exploration,working hypothesis is different for different type of fluid dynamic systems.A case study indicates that the principal of fluid dynamic systems approach is very efficient and helpful in analyzing the formation and occurrence of oil and gas pools.

In this paper,on the basis of sedimentary texture of the rocks,thd formations are considered as transversely isotropic materials.The equations of three principal in-situ stresses,the converting formula of elastic parameters in tilled formations and the calculated equation of formation fracture pressures(EFFP) in transveresly isotropic formation are given.In this paper,the oil-fields practical data are used as an example.Comparing two calculated values of isotropic EFFP and transveresly isotropic EFFP show that it must be considered of the anisotropic in in-situ stresses application and the transversely isotropic EFFP has less error.

The Renqui Oil field possesses the biggest carbonate reservoirs in China.The high recovery efficiency had been obtained during its major development stage,the depletion and cyclic water flooding development was carried out on its two reservoirs since the beginning of later development stage.The lease experiment has been lasted for six years.This paper presents a reservoir simulation technique to calculate single kind of measurement planning,from which each kind of measurement was decomposed.The main objective of the study was to evaluate the affectation of the unsteady water flooding to increase production of the Renqiu Field.The result indicated that,additional oil production by the depletion and cyclic water flooding is less than overall additional oil production by all kinds of stimulation and adjustment wells,even adjustment wells play an important role in increasing production.Unsteady water flooding cannot be replaced by the other stimulation and adjustment wells in the matter of EOR.It is feasible that unsteady water flooding might be used to carbonation reservoir in later development stage.

Xia-Ermen oil field entered the high water-cut production stage after 20-year water flooding development.The petrophysical and microscopic parameters of the formation rock were largely changed by the long-term water flushing because of the low maturity of the rock.There are many features:reservoir formation types increased,distribution and coordination number of pore and throat of porous rock were diversified dramatically,relative permeability curve were largely changed,wettability displacing efficiency and residual oil distribution of the formation were varied greatly.All of above mentioned changes made the formation more heterogeneous.The technique presented in the paper consist of several methods,such as couple coring well(100-meter well distance) analysis,core physical modeling test,comprehensive log interpretation,dynamic analysis,electronic probe and sensitivity evaluation.The developed methodology can be extensively applied to other high water-cut oil field in East China.

Porosity is an important parameter in reservoir description.The paper discusses the principle of porosity prediction with seismic data based on the propagation theory of seismic wave in diphase medium.A method of Complete Utilization of Sample Information(CUSI) to predict porosity is presented considering the fact that both the complexity of seismic porosity prediction and the function approximation of BP network need complete sample information and the low efficiency of learning(not suitable for seismic feature optimization).This method uses the capability of local approximation of CUSI network and establishes a function relation between seismic feature and porosity with borehole datd and the seismic data around the borehole to predict the porosity.The paper also presents the optimization principle of seismic features and the seismic feature optimization method based on genetic algorithm in porosity prediction with CUSI network.The result of the application showed that the method improved the porosityprediction precision with seismic datd.

The 8 important water drive curves are recommended,and water saturation vs.water cut relation which show their characteristics of oil-water seepage flow were derived,so their substance for water drive characteristics understand comprehensivrly.Due to derivation is invertible,in this sense,one have already completed the derivation for all 8 important water drive curves.The Kathakov water drive curve is a general form.The Yu Qitai water drive curve 1,the Sipachev water drive curve and the Sathonov water drive curve are its particular case.Yu Qitai water drive curve 1,Sipachev water drive curve and Kathakov water drive curve at m>0 all are rational in whole process of water drive,but Kathakov water drive curve at m=0 i.e.Sathonov water drive curve can not be applied under high water cut.YU Qitai water drive curve 2 is a general form.Nathalov water drive curve,which is its particular case at m=1,can not be applied under low water cut.By Kathakov water drive curve and YU Qitai water drive curve 2,a combination of generalized water drive curve which can be applied in oil fields of two large types in Chian-water flooding bedded oil fields and bottom water drive carbonate rock oil fields has been made of.The combination of generalized water drive curve has very large theoretical sence and useful value,but judgement of users intervene obtaining parameters much in its application,so their general forms-Sipachev water drive curve and Nathalov water drive curve which obtaining parameters are easy to have very large useful value.Maksimov-Tong Xianzhang water drive curve can not be applied under much high or much low water cut,but it can describe performance of water drive very well in middle water cut,so its useful value is also very large.Attentions should be paid to its applicability of water cut boundary line,the curve type is too rare to practically use.

Mary mathematic models have been applied to forecasting production rate and cumulation of oil and gas reservoir.It is difficult for oil engineers to use the models correctly because these formulae are miscellaneous,isolated each other,and have no any relationship among them.This paper presents a generalized model of forecasting production rate of oil and gas reservoirs.The model was deduced analytically and inductively based on life-limit system theory.By the way,the widely used twelve models in life-limit system theory can be obtained by selecting reasonable constant of the model.The simplified twelve models include famous economis increasing Gompertz model,Logistic Model widely used in society field,Arps hyperbolic decline model in petroleum engineering,Gamma Model and HCZ Model which covered the common branch of life-limit system theory.

Automatic control technology of bit trajectory is up to date field of drilling engineering in the world.Basic problems on design of automatic control system of bit trajectory are anslyzed in this paper.At first,the objective of automatic control of bit trajectory is established and ezpressed in mathematics;acccrding to the arrangement of system function,the basic structure of automatic control system of bit trajectory should be the supervising control structure,which consists of two branch systems.The structural features and control methods of these branch systems are discussed.Finally,the basic principles are clarified for the design of automatic control system of bit trajectory,which has important guiding sence.

Total length of linked production pipes are about 1500-7000m,side wall pressure is over 20MPa.There are many kinds of polluter such as dirt and sand and flaws on the wall,that is serious danger.Ultrasonic and eddying detector are not appropriate to detect flaw,and high pressure whater detector can only detect a little flaws such as hole but the speed is low,the operation is complex.When a steady and strong enough magneic flux pass along the pipe wall,flaw in wall can change the flux passing through the wall and form leaking magnetic field.According to the principle,the high speed flaw detector of extact oil pipe is desighed and produced.It can detect flaws that in or on pipe wall such as craze,hole,hollow,groove and changed wall thickness.Detecting speed is 15-50m/min,ability D1.0 hole,diameter of tube between 50-150mm.The operation is simple,detection is steady and reliable.

According to oil-gas gathering process of single or double ring-type pipelinemixing with heat water,a method of calculating hydraulic and thermodynamic parameters such as flow,ratio of water in oil,pressure,temperature,specific heat for oil,gas,water pipe net is presented.A parameter optimization model for multiobjective is established with heat and electricity consumption,system investment as an objective function,and with pressure,temperature,range of diameter of pipes as restrain conditions.A method of solving the problem is given also.The authors pointed out that the higher investment and electricity consumption are resulted from the longer section with mixing heat water in the process of double ring-type pipeline.Mixing water is more concentrated in the ring part of the single ring-type pipeline process,so the heat consumption is larger in this process.Based on the objective function in this paper,the process of double ring-type pipeline for mixing heat water ought to be used.

This paper analyzes the drops behavior characteristics in the gravity separation field under the guidance of fluid mechanics,and discusses the limitations using tradition setting velocity model of the drops in engineering apply.The relation of the settling velocity and separation time with the drops grain size under the collision polymerization of the drops is also discussed in the paper.By comparing the setting velocity,separation time and horizontal displacement between the collision polymerization drops and the single drop,the drop's model of setting velocity under the collision is derived.It is necessary to use the collision polymerization model to design the gravity type oil/gas/water separation equipment in the futurd.

Based on the characteristics of rod pump pumping and the indoor experiments,this paper has determined rheology of polymer solution applied in oil field,and have set up the equations of pump pressure,intake flow velocity,intake flow height,and discharge coefficient during suction process.Indoor experimental survey shows that during suction process the plot of pumping pressure vs.plunger displacement is basically concave-down and non-symmetrical parabolic type.In the case gas is present,velocity of pressure drop in pump increases.Practical examples on the spot has shown that pump's discharge coefficient is affected by the producing GORs,polymer concentration,submergence depth,stroke,stroke rate,pump diameter etc.,of the factors what have major effect is producing GORs,polymer concentration and submergence depth.Practical analysis in oil field is agreed with practice on the spot,which further verifies that this theory is right and reliable.

The Palaeozoic petroleum geological condition of Huabei area had been analyzed in detail from the petroliferous system angle.The Lower Palaeozoic is mainly a set of marine carbonate rocks,and the soruce rocks located in the sag region has large potential,such as the Cambrian Fujunshan and Zhangxia formations and the Ordovician Majiagou and Fengfeng formations in the section.The Huanghua-Linqing structural belt is the favorable exploration region.The Upper Palaeozoic is mainly a set of coal measure sediments with the characteristics of large thickness of coal and dark mud bed with mature-overmature evolutionary degree,so that,the upper Palaeozoic has large potential as well.Based on the hydrocarbon generation history of Palaeozoic source rocks and the interrelations between the migration and accumulation of oil and gas,it has been identified that the Palaeozoic has the condition of forming the primary oil and gas pools.The key problems of the Palaeozoic prospect are the potential of secondary hydrocarbon generation,distribution range of source rocks and preserve condition of oil and gas.The Palaeozoic petroliferous property had been studied based on a large amount of basic geological informations and the conclusions had been obtained that the Bohaiwan area is a favorable Palaeozoic oil and gas prospect place with good secondary hydrocarbon generation and petroleum preserve conditions.The southern Nanbei area is a good Palaeozoic gas prospect place with good hydrocarbon generation and petroleum preserve condition,but high evolutionany degree of source rocks,and the Qinshui area is not an ideal place for the Palaeozoic petroleum prospect becausa of the strong hydrodynamic and poor petroleum preserve condition.

Based on the analysis of wave processes and their approach,the secondary generation of hydrocarbon was studied by the buried history of the wave model in this paper.And the analysis of typical oil and gas reservoir formation in the central and north part of the Tarim Basin proves that uplifting at the late Palaeozoic is the controlling factor for the reservior formation in these areas.From the viewpoint of Wave process controlling the mutiple superposition of the basin,the author discussed that the multiple cycle development of a basin controls the multiple generation of bydrocarbon,mutiple reservior formation,the destroy of reservoir by uplift and subsidence,the change of structrual spillpoint by differential subsidence result in the remigration,the change of oil and gas quality by subsidence while the reservoir formed or after that.The distribution of oil and gas in Tarim Basin was discussed by the wave theory,combining with the analysis of petroleum characteristics of Tarim Basin,pointing out that the plunging section of north-west part of Tazhong uplift is a favorable area for exploring the primary reservoir,and the non-structure reservoir at the north and south part of the Manggar sag is also an importan domain for exploration.

Based on the principle of lithologic sequence,Dongying formation in Shenghai area,Jiyang depression,are consisted of five stratigraphic sequences,and to be controlled by two depositonal systems.In sequence stratigraphic systems,the vertical distribution of reservoir is controlled by base-level cycle changes and is in the lower parts of sequence units.The lateral distribution is controlled by palaeogromorphology including erosional valley,slope break on the clinaform formed by pre-Tertiary buried hill and up-dip stratigraphic pitchout.Four turbidity channels and six potential reservoir bodies are predicted in the destination sequences,which have been successfully confirmed by drilling.

Tsaidam Basin is quite a large sedimentary basin in Western China.However,the oil and gas reserves discovered there are far from satisfactory in consideration of the basin area and the amount of its oil and gas resources.The prerquisite for making breakthroughs in exploration is finding out the geological laws governing the formation of large-scale oil/gas fields.Several oil/gas-bearing structures have been located in Lenghu-Nanbaxian structure belt during prospecting in northern part of Tsaidam Basin in recent years.Meanwhile well LK-1,one of our scientific exploration wells,penetrated Jurassic source rock as thick as some thousand meters.All these indicate that favorable conditions exist for the formation of large-scale oil/gas fields.In the present paper the authors analyzed SRI of Jurassic source rock,the characteristics of reservoir rock and caprock,the association of reservoir,caprock and the features of oil pools.In combination with the recent exploration achievements,it has been concluded that a large amount of oil/gas accumulation probably exist in Lenghu -Nanbaxian structure belt.In addition,based on the geological conditions and the characteristics of the structural traps,the targets for the near-future exploration activities are proposed by the authors.

Exploration practice showed that the Paleozoic carbonate rock buried-hills with favorable hydrocarbon source and reservoir rocks are a kind of important oil and gas pools in Bohai Bay Basin.The Cambrian-Ordovician carbonate rock buried-hills in the slope of Dongying sag occupy fine conditions of petroleum accumulation.Baminanhe area and Caoqiao buried-hill oilfield are located on the same slope structure zone and it is predicted that both have the similar model of petroleum accumulations.Therefore,Bamianhe carbonate rock buried-hills are thought to be a petroleum exploration area with high potentialitices.

The relative high abundance of dinosterances has been found in the member No.1 of Qingshankou Formation and the members No.1 and No.2 of Nenjiang Formation based on the geochemical studies of source rocks in Songliao Basin.The widely distributed dinosterance in source rocks indicates that there were two periods of marine transgression in geological history.The relative content of dinosterane in source rocks in the member No.1 of Qingshankou Formation is higher than that in the members No.1 and No.2 of Nenjiang Formation.In addition,C ₃₁steranes have been identified only in the source rocks of member No.1 of Qingshankou Formation.This is not only attributed to differente algae in these formations,but also related to the differences between ancient sedimentary environment and the salinity in source rocks.The molecular fossil assemblage shows the relatively high salinity in source rocks of the member No.1 of Qingshankou Formation.It may indicate wide marine transgression in the period of the member No.1 of Qingshankou Formation sedimentation.The content of dinosterane has been tentatively used to determine the direction of marine transgression.

The method of measuring radioactive radon in the soil is simple,economic and effective.It can define the range of oil field through finding the transitional belt of oil and water underground.The mech chanism is that the natural γ goes from strengh to weakness from oil layer to the earth's surface in vertical section,and the natural γ goes strong in the border and weak above the oil layer in different oil layers in plane.Experiments show that whether structural reservoir or lithologic reservoir or other kind of reservoir,the existing of abnormal radon is clear.Using this method evaluate sand boby,the result not only tallied with test well information,but also the two affirmed and negated test wells have been confirmed by drilling in later period.The prediction to a certain structure in new region has been verified.Defined borders in rolling developed area coincide with reality of production.This method can provide new developed well location for extending border in old region.

Renqiu WMS reserovir is on the high water cut development period after 20 years production.Elaborate explain of 3D seismic data and technique of variation provide credible technique which assure the study of top WMS.The errors between drilling data and the actual depth of enter buried hill was less than 20m.The study gave the following conclusions: (1)Residual oil controlled by ancient top of buried hill is the best potential type in later period of reservoir development.(2)The research of relationships between top of buried hill and geological formation is the main means to find out reservoir temaining oil.(3)Upper part of two block of fault is the formation for residual oil.This study provided solid technique support for keeping stable yield of high water cut formation of the reservoir.

A predictable model was set up by using Stochastic simulation method for high water-cut development stage in East China oil fields.The distribution of the parameter was predicted on the basis of sedimentology and geostatistics.A structural model and the predictable sedimentary geology model of faces were established by taking Second Section 7-8 sand groups as an example of the reservoir.The relations between these models and the remaining oil were analyzed.The study is of important significance to tap the latent power for eastern oil fields.

The automatic analysis and unique results are the goal of well testing.This paper proposed an optimal well test analysis method based on genetic algorithm.Genetic algorithm is a fast searching technique with the principle of ‘Survival of the fittest'.The fittest of each solution is evaluated to undergo the action of the crossover and mutation operators in each generation.Especially,the genetic algorithms are suited to problems with non-linearity,discontinuities,etc in each generation,all of which can cause traditional optimization schemes to fail.It is not necessary to specify initial estimates for the parameter values and objective function continuous.The method is superior to simple genetic algorithm.In order to maintain diversity in the population and sustain the convergence capacity of genetic algorithm adaptive probability of crossover and mutation are used.The optimal values of reservoir parameters can be obtained.The good well test results can be obtained by combining with automated type curve matching method of nonlinear trgress.Two field well test data demonstrated the method is efficient.

The widely used Cartesian grid has some disadvantages in the description of geologically complex reservoirs.In addition,finite difference method based on Cartesian grid causing significant orientation effects.PEBI grid takes advantages of finite elements of flexible approximation of reservoir geometry,and reduced orientation effects by using window techniques.It is easy to be refined and be applied in finite differente simulators.This paper presents the differente equation of control volume finite elements,with a method of automatic triangulation and PEBI grid generation.2-D single-phase model and two-phase model were designed to test the feasibility of the PEBI grid.The numerical results indicated that PEBI grid could simulate radial flow near the well bore with high accuracy.The results are consistent with the analysis solution and PEBI grid reduces grid orientation effects greatly comparing with 5-point finite-difference method.

The vertical interference test is the most effective method determining vertical permeation and researching sealing ability of interlayer.In order to research the stability of interlayer,a vertical interference test method were developed.It can interpret the distance from the well to pinch-out or "open window" of interlayer.This paper introduces the principle and composition of vertical interference test in a multi-layer reservoir.Packer separates the well bore and the formation is divided into upper and lower layers.This paper considers two basic models:disk pinch-out and ring window.The upper and lower layers are permeable and middle layer is impermeable within the near well bore and further more has a pinch-out extending from it or an "open window" in some regions.We establish the theoretical model and find the solution.On the basis of the approximate analytical solutions at an early and a later time period,a vertical interference test method has been designed for interpreting stability of interlayer.A field example is then presented.The data is analyzed.It demonstrates that this type of well testing method is applicable.The result provides foundation for development of multi-layer reservoir,for example,decrees and adjusting well distance,dividing development layer.

Seismic While Drilling (SWD) is a drilling technique integrated with seismic technique.The main advantages and application of SWD are summarized.By SWD,the drilling bit can be positioned accurately,the drilled formation,lithologic characteristics,faults and fracture zone can be identified,the formation ahead of bit and abnormal formation pressure can be predicted.SWD can be used in well drilling trajectory control and can also be used in exploration wells to discover oil reservoir and protect oil reservior from damage.Without any downhole instrument,the system of SWD is equipped with a sensor on the top of the drillstring and reservers on earth surface.Seismic data are processed and utilized at the well site for real-time drilling decision.SWD will significantly reduce drilling cost,and increase economic benefits of exploration and ecploitation.

Two kinds of petroleum sulfonates were separated into different polar fractions by means of silica gel column.Phase behavior of different polar fractions and their blends have been studied.Blending different polar fractions at some appropriate proportions,however,do give middle phase microemulsion systems with high solubilization parameters and ultra-low interfacial tension on alcohol condition.Fractions alone of petroleum surfonate could not form middle phase microemulsion on alcohol-free condition.Blending at some appropriate proportions,blends of two or three fractions of petroleum sulfonate can not only form middle phase microemulsion but also reveal.High solubilization ratio and ultra-low interfacial tension at optimum salinity under alcoholfree condition.Parameters of phase behavior changed when the proportion of fractions changed.Experiment results indicate that petroleum sulfonates are themselves multicomponent surfactant that composed of different polar fractions.There are synergism among different polar fractions,polarity is important in synergism.It is suggested that the quality of petroleum sulfonale is supervised by the copmposition of different polar fractions.

Fuzzy mathematics and AHP (analytical hierarchic process) are applied to establish a new technical and economical evaluation model of slimhole drilling,and the model is used in drilling practice.In the model,eleven indexes of slimhoe drilling are comprehensively analyzed,several indexes are changed into membership degrees by fuzzy mathematics.Several indexes are combined step by step,based on AHP.Thus,the complexity of drilling economic evaluation is extricated.As a result,a technical and economic analysis would be made quantitatively by drilling people.

In view of the speciality of displacement and strain fields around crack tip,the test procedure of sticking film moire interferometry has been introduced into the measuring of fracture parameters for pressurized piping.With the theory of wavefront interference,equations representing the displacement and strain in piping surface has been obtained.Measuring theory of fracture parameters has also been examined.It is found that the measuring results obtained by sticking film moire interferometry become sensitive to rigid boby movements due to the existence of piping curvature.Furthermore,when the curvature and the area to be measured are big enough,the effects of rigid boby movements to the measuring results may not be eliminated even the symmetric incident light path is adopted.To increase the measuring accuracy,some improvements on experimental techniques of sticking film moire interferometry have been made,some supplementary devices relating to the cutting,fixing,and sticking of the film are devised.Moreover,a software of measured data processing is developed.With the improved sticking film moire interferometry,the displacement field,strain field,strees intensity factor,crack opening displacement and J-intergral around the axial through crack tips of three pipings are measured.It is showed that the measured stress intensity factor and crack opening displacement are approximate to the theoretical solutions based on "D-M" model,value of J-integral in plastic region around crack tip varies as the integral path,and as the integral path come near the elastic region, J-integral value decreases to the theoretical solution.

An optimal model is proposed for predicting the pressure drop of two-phase flow in gas well tubing and annulus,based on the measured data from the gas field of southwest Sichuan,China.The liq-uid holdup in tubing is modeled as a function of dimensionless gas and liqiuid velocity numbers,as well as liquid viscosity number.And the liquid holdup in annulus is modeled as functions of ratio of gas and liquid superficial velocity,density and viscocity.Absolute error as goal function,the coefficients in the liquid holdup correlation and the modification factor of absolute roughness are optimized,based on the field flowing data and the minimum pressure drop.This model is evaluated by using 37 wells field data,23 in tubing and 14 in annulus,and compared with five commonly applied empirical correlation.The results of this model are satisfied and made closerto actually one.Sensitivity of the model to liquid/gas ratio is also presented.

Corrosion of Sulfate-Reducing Bacteria (SRB) is one of the main causes of Microbiological-Inducing Corrosion in the injection water of oil field.At present,bactericides are widely used to inhibit SRB.Specially "1227" (ducedyldimethyl-benzyl ammonium chloride) has been used more widely.However,"1227" was used so long that SRB produce resistance to it.Therefore,it is necessary to study on how to deal with the drug-resistance bacteria.It has been reported that bacteria could be induced drug-resistance to a bactericide when it is used too long.But it is impossible that the drug-resistance of bacteria can be produced by two kinds of bactericides simultaneously.There are three actions by merging two kinds of bactericides,such as coordination,addition,and restraint.A new quick test method is adapted to study the complex bactericide.From Loewe equivalent curve,a complex bactericide with the merge of a new synthetic bactericide (BQA) is obtained and Metronidazol flagyl (ME),has good effectiveness on SRB and inhibit the drug-resistance SRB with the low-cost.It has satisfactory effectiveness on not only the drug-resistance bacteria produced from the lab,but also the drug-resistance bacteria sampled from the oil field.In addition,to apply the complex bactericide,further research work in oil field is needed.

As everyone knows,rough terrain and complex subsurface are often co-existent,and a lot of related special problem have to be considered by the seismic engineer.Some of the problems are in fact common to loess plateaus and dune deserts.It is therefore a technology much concerned by petroleum explorationists and so awaiting seismic workers to devote their efforts in the discussions and experiments for knowing and doing better.This paper begins with stating four major technical problems,i.e.,.back scattering,static corrections,migration of data and coupling to the earth,then from a practical point of view in pursuing portability as well as reasonable simplicity, presents how the experiments could be performed.The opinions or proposals included herewith need to be confirmed in the future.

How can the method of prestack depth migration solving geological imaging problems? The answer is given by the basic concept of migration in time and depth domain,and two gages are given in this paper.The relative error of horizontal distance and vertical depth are also given by using the methods of migration in time and depth domain,and these can tell us which geological structure the method of depth migration must be used.The method of depth migration is used to solve the imaging of stratigraphy above which there are slant layers and horizontal viable velocity.In the paper,the depth migration method based on Radon transformation-Gaussian beam principle is introduced.The viewpoints of ray and wave theory are combined in the method which can help us solving the imaging problem of conti-nental deposit stratigraphy.The successful key point of depth migration is the accurate velocity modeling.Therefore,many methods of ve-locity modeling are analyzed.

Oil sand formation of about 90m in thickness and a large number of crevasse filling bitumen were first discovered in Upper Jurassic in the Northwest Qaidam Basin.Characteristics of the extracts of the oil sands and bitumen show that they are similar to Jurassic oils of the Northeast Qaidam Basin and differ from Tertiary oils in the Northwest Qaidam.Geological surveying indicates that there are thick Lower-Middle Jurassic source rocks in the Northwest Qaidam Basin. Biomarkers and other natures of extracts of the Jurassic source rocks are similar to the oil sands and the crevasse filling bitumen.Correlation of the oil sands and the source rocks suggests that the oils in the sands were derived from the Jurassic source rocks.The discovery of the oil sand and crevasse filling bitumen presents important signifi-cance to petroleum exploration in the Qaidam and other Basins along the Altun Fault.