According to present situation of exploration, the cause of formation of basins and age of production horizons, oil-bearing basins in China's continent can be divided into a longitudinal zone composed of the Yilan-Yitong-Bohaiwan-Jianghan group of basins and a latitudinal zone composed of the Junggar-Erlian-Songliao group of basins.These two zones contain 94% of the general output and 99% of the general reserves of China's petroleum, so we call them the longitudinal and latitudinal petroleum rich "golden zones".Based on evolution of China's plate tectonics, tectonic setting of basins, and conditions for oil-pool formation, this paper analyses the general and individual characteristics of the longitudinal and latitudinal petroleum-rich zones (contrasts them with two kinds three types oil-gas tectonic units) and concludes that the latitudinal zone has the most advantageous prospects for petroleum exploration.We therefore suggest that this latitudinal zone be considered the principal region for petroleum exploration in continental China within this zone, exploration should especially be strengthened in the Jungger basin, where may be discovered an especially huge oil field.

The Permian is the important marine carbonate strata bearing oil and gas in south China.Its potential of oil and gas is very large, but little exploration was done.Except the Sichuan basin, no important brcakthroughs of oil and gas exploration have been made in marine carbonate strata in south China.On the basis of quantitative study and mapping of lithofacies paleogeography, the indepth study was made on the types, distribution and relation with sedimentary environments of source rocks and reservoir rocks of the Permian of the area, on the nature and distribution of regional and local capping beds, and especially on the oil and gas preservation units of the Permian formed alter many times of important tectonic movements.Five most favourable areas for oil and gas exploration were delineated out.They arc the Sichuan basin and Jianghan basin for oil and gas pools of concealed reefs as well as oil and gas pools of dolostones related with reefs and banks, the Yunnan-Guizhou area for coal bed gas, the Nanpanjiang area for isolated carbonate platforms in the deep water basin, the Shiwandashan basin areas with good preservation conditions, and the broad conjunction zone between the Jiangnan platform and basin.We hope that great breakthroughs of oil and gas exploration in the Permian and all other marine carbonate strata of south China will be made in the near future.

The Tarim-south China massif was taphrogensised after Middle Triassic.Due to the change of the reginal tectonic pattern during the formation of the Sichuan basin, the lower Paleozoic hydrocarbon has been originated in Sichuan basin and has undertaken two and one proccesses of migration-accumulation before and after the traphrogeny respectively.It is predicted that the present gas pools should be disduted at the margins of the broom anticlinal areas of the southeast Sichuan, where the conservation features would be better in the anticlines of the structural highs.

The study on structural stress field and hydrocarbon accumulation of Tarim basin, which dealing with geophysics, tectonics and petroleum geology is very important in theory and application.We model the present stress fie1d of Tarim basin with survery data, seismic source data and geological pattern of the basin, and study the relation between present stress field and hydrocarbon accamulation.With the idea of comparative geology, the relation of stress fields and hydrocarbon accumulations of each period in geological history evolution were derived.Last, we can get the main idea of the migration and accumulation of hydrocarbons, which related with the structural stress field of the Tarim hasin.

For many years, thin-layer sandstone prediction has been a major probleum that trouble geologists during oil field development.In view of depositional characteristics of thin-layer sandstone in Yushulin oil held in Daqing, this paper adopted a new method of reservior transversal prediction, cluster analysis and incidence degree analysis, to predict thin-layer sandstone quantitatively.It combined geology, logging, seismics, mathematics with computer technique and took YI group of Shu 32 well area in Yushulin oil field as an example to quantitatively predict thin layer sandstone, drilling tested accuracy is 86.5%.

Estimating reserve by multiwell interpretation technique and geostatistics can avoid many problems which are often found with a small number of coring data by traditional methods.This method is especially suitable for heterogeneous reservoir.It is applied in reserve estimation of Shen84 block in ShenYang oil field which is very heterogeneous with satisfactory results.

Based on detailed research of the hydrocarbon concentration sealing mechanism, the evaluation index of hydrocarbon concentration sealing ability of caprock by calculating gas diffusive velocity through caprock under the action of supposed hydrocarbon concentration was established by Fick's law, it's also applied to the caprock evaluation of Daqing Placantidine and its western area.This result indicates that this method not only evaluate hydrocarbon concentration sealing ability of caprock quantitatively, but also evaluated caprock in the plane.It is a practicable method for evaluating the hydrocarbon concentration sealing ability of caprock.

On the base of detailed research on marine source rocks in China by means of organic petrology and geochemistry, a new maceral-marine vitrinite has been confirmed.This maceral origins from faunal organic matter, were formed through the strong biochemical degradation of bacterials under the reducing to strong reducing conditions.Thermal-simulating test results showing that marine vitrinite is characterized by late hydrocarbon generation, and its oil peak occurs in the region of vitrinite R _o 1.0%~1.30%.Marine vitrinite is a good gas source material although its liquid hydrocarbon production is about 6%~8% of its total weight.The reflectance of marine vitrinite can be used as a good maturation level index after high maturation level stage.

Comprehensive estimation of various plug-releasing technologies plays an important role in guiding oilfield production and keeping stable and high productivity.There are many fuzzy factors in the estimation of plug-releasing technologies of oilfield, so it is more reasonable to use the method of fuzzy comprehensive estimation to solve the involved problems.In this paper, the method of fuzzy comprehensive estimation had been applied to the synthetical analysis of the effects of seven plug-releasing technologies in Daqing south 4-8 area in 1995.The results show that thermochemistry Ⅱ and low-harm delay-acid technologies are the best, high-frequency hydraulic vibration and supersonic technologies take the second place, thermochemistry Ⅰ, polytene acid and high-energy gas crushing technologies take the third place for the area of the oilfield at present.

Because of friction loss in horizontal wellbore, pressure drop of horizontal wellbore may equal to that of reservoir pressure drop, which results that the reservoir pressure drop at the tip of horizontal wellbore is rather small or equals to zero, this phenomenon often appears in high permeability or coning reservoirs, pressure difference of these reservoirs is low or limited.Therefore, studying the design method of optimal horizontal wellbore length has a guide meaning to development program design of horizontal wells.By dividing three reservoir type cases (bottom water drive reservoir, gas cap and bottom water drive reservoir, gas cap drive reservoir), the paper derives flow model in reservoir, flow model in horizontal wellbore, the optimal length model of horizontal wellbore, in the process of derivation, the factors, such as flow regime (laminar flow, turbulent flow) and relative roughness of wellbore, which have influence on productivity of horizontal wells, are considered.Finally, the paper gets a few conclusions by example calculation.

The oil and gas production trends and their Γ distribution in probability statistics theory are studied systematically.A Γ model for predicting the oil and gas fields production bas been presented in the paper.The model can be used to predict not only the variation of oil and gas field production and cumulative production with time but also the recoverable oil and gas reserves, maximum yearly production and its corresponding time.

A new model is given for the production behavior of a closed gas reservoir.It considers the gas exchange between high and low production regions, caused by the pressure difference.It is an improvement of the traditional material balance method.With this new model, the production behavior of the central gas field under different well patterns and development index and the behavior of the exchange rate between regions were studied.This made it clear that the gas exchange, caused by regional pressure differences, is a very important factor for the performance of a gas reservoir.For a low permeability gas reservoir with a fixed steady production period and total output, its unbalance degree of development should be increaced to improve its economic efficiency.This means more wells should be drilled in the high production region so that part of gas in the low permeability region can be produced by the wells in the high production region.

To properly predict the output of an oil and gas reservoir is of great importance for improving the production effect of the reservoir and enhancing the effect of reservoir stimulation.Based on the control theory, the performance indexes of an oil and gas reservoir can be accurately predicted using suitable function simulation model.The theoretical bases of some stationary function simulation models are described.The gas production of the volatile oil reservoir of Shuangyang oilfield is predicted in initial stage of development, choosing an AR model of a random sequence in which the average value is not zero.The prediction precision of the model is up to the engineering requirements.

Relative permeability curves reflects the law of multiphase flow and distribution in reservior rock.According to experimental study on in-situ rheology of polymer solutions through porous media, an effective viscosity dependence of polymer solutoion upon phase saturation and fractional flow were obtained, in which the adverse influence of polymer adsorption/retention and non-Newtonian effects were eliminated.Therefore, a steady-state flow technique was established and modified for testing relative permeability curves of polymer flooding.At high reservoir temperature of 70℃, the relative permeability curves were successfully measured for both polymer/oil system and water/oil system after polymer slug by using the steady-state flow method.Suitable empirical equations were adopted for both curves.Then, the relative permeability behavior for polymer flooding was discussed and, effects of polymer molecules retained in rocks and free in aqueous phase were also analysed, thus revealing the law of multiphase flow and oil displacement mechanisms during polymer flooding.Consequently, the basic and important parameters were provided for numerical simulation, pcrformance prediction and effectiveness evaluation of polymer flooding.

The morphological evolution characteristics of viscous fingering, which occurred in two-dimension Hell-Shaw cells with the viscosity ratio V _R between the displaced and the driving fluids varying from 1 to 10000, were simulated by a modified DLA model on off-lattices, which was some different from the conventional method and the effect of surface tension was also taken into account.Both the shapes of fractal clusters and the fractal dimension obtained by controlling the parameters in the present model are in good agreement with the experiments.The present work indicates that the fractal dimension D and the viscosity ratio V _R follows the formula D=2.0384-0.0384V _R ^1/3.The sweep efficiency is proportional to the logarithm of V _R, E _S=1-0.1795log ( V _R).So, the greater the value of V _R, the less the fractal dimension D and the lower the sweep efficiency E _S.Thus, the parameters such as fractal dimension D, which describes the complexity in a system, viscosity ratio V _R, which influences the dynamics of fingering, and sweep efficiency E _S, which scales the EOR programs, were connected by the present study.The fractal dimension can be reasonably regarded as a useful parameter to evaluate the sweep efficiencies and oil recoveries.The present results suggest that the improvement in sweep efficiencies for EOR programs may be achieved by the means of increase in fractal dimension of viscous fingering.

As the latest high-grade technology developed in the middle of 1980s, liquid-liquid hydrocyclones occupy a very important place in the oil surface engineering.Now the applications of the technology in our oil industry will be one of the significant scientific and technological projects of CNPC (China National Petroleum Corporation) in the Ninth Five-Year Plan.On the basis of combining our research works made in recent years with the extensive analysis of internal and external references, the development of liquid-liquid hvdrocyclones and the related technologies are comprehensively reviewed in this paper.Finally, in order to promote the realization of the project in the Ninth Five-Year Period, some suggestions are put forward.

In oil-gas gathering process of tree type double pipes mixing heat water, energy consuming of system is related to quantity and temperature of mixing water, diameter of pipes, output of wells, ratio of water in oil, viscosity of liquid transfered.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 model of parameters optimization is established with energy consuming and investment of system as an objective function, pressure of well head, temperature at booster, range of diameter of pipes that can be used as restrain conditions.The model is non-linear and can be solved with direct array square method.Chart of calculating process for computer is given.Energy consuming can be decreased while engineering design is made with the software having been worked out, and rate, quality of design can be increased.

A kind of device which can keep the casing at the center of borehole and can also generate helical flow of cement slurry, which is the Spring-Whirlflow Casing Centralizcr, is presented in this paper.Based on experiments, the whirlflow law generated by this centralizer is analyzed detailly.The rules of effect of factors are obtained.To make foundation for analyzing the displacement efficiency of whirlflow cement slurry, formulas of whirlflow length and angular velocity are established.The field applications show that the device, which is designed by the theory of this paper, has good effects on improving displacement efficency and cementing quality.

Based on statistical analysis of late years' meteorological data in the Kelamayi oil fie1d, the probability distribution and statistical characteristic of recent years' extreme wind velocity were acquired.Reliability of the tower derrick was analyzed for derrick subjected to extreme wind load and operating load in which the rcliability of resisting overturn was estimated by using JC method.The computer program was revised to consider non-normal distribution of the basic variables and the relations of those variables.The dominant failure modes were determined by branch-bound method combining with some newly developed improving measures.The failure probability of structural systems were estimated by using Ditlevsen's bounds based on the dominant failure modes and revision of the upper bound by discarded failure paths.The result shown that the reliability indexes of derrick itself came up to the stipulated requirements, but the weakest point was the overturning stability.If the anchoring force were greater than the calculated value, the derrick would not be ovcrturned under the extreme wind load.

A calculation method of the sealing parameters, such as sealing pressure, eccentricity and so on, is presented by applying the theory of non-linear great deformation.The mechanical model of ram assembly is also offered according to the working conditions of ram blowout preventer.In the light of sealing conditions of normal working rubber core, the rational range of the eccentricity is given.Structural optimization design for the ram rubber core is carried out on the basis of the above.

Stress corrosion emerged in the 1000m ³N-TuF5O steel storage sphere may develop a great deal of surface cracks, which need to be controlled to ensure safety in production.Factors effected the development, propagation and stability of the cracks are determined by defect detecting tests and theoretical analysis.This paper has provided a scientific basis for stress corrosion prevention and defects repair.

This paper gives a diagnostic model for sucker rod pumping of the horiznotal well, in which a system including the sucker rod sting subing string and liquid columns is considered.This model consists the hyperbolic partial differential equations, boundary conditions and cyclical conditions of the system.The form of the equations has been changed with fecture transformation so as to calculate conveniently.This model can be used to horizontal wells and that of vertical well, slanting well and directional well are special cases.The results of diagnosis by using the software to calculate pump dynamometer cards for four wells are consistent with the pump conditions.

A great deal of important achievements have been gained in Qaidam basin by exploration for oil and natural gas since 1950s,the exploration practice in recent years have shown that the degree of prospecting for oil and natural gas is low,and many geological questions are still not solved.According to the integrated analysis for the evaluation,the depositional characteristics and the law of oil and natural gas accumulation Upper Palaeozoic,Mesozoic and Cenozoic strata all have great resource potentialities.Thus,the exploration for oil and natural gas must be enhanced,and great breakthrough will be gotton in the future.

Based on the comparative study of coal related hydrocarbon maturity and source rocks maturity of coal measures in Turpan Hami basin,and combination with adsorbed hydrocarbon power of coalrock in different degree of coalification,the characteristics of hydrocarbon exhaust are discussed and the different charateristics of hydrocarbon exhaust of source rocks of coal measures in different rock associations are pointed out.It is confirmed that hydrocarbon migration distance is short,the vertical hydrocarbon migration is dominant.By studing overpressure evolution,tectogenesis intensity,interrelation of overpressure argillutite and time spasce oil gas pools living,pressure effect plays a leading role in the process of oil and gas accumulation,and an existance of overpressure argillutite is impotant condition of oil/ags accumulation in coal measures.

Tarim basin,located in NW China,is a giant hydrocarbon bearing basin.It underwent the Caledonin,Hercynian,Indo China,Yanshan and Himalaya tectonic movements.Faults are most obvious structural features for all structural deformation styles compresso wrench faults,mainly distributed on uplift zones in the basin,is one of the most widely developed structural styles.A total of 9 compresso wrench fault belts have been identified.They can form three kinds of association geometry(broom,"入" and en echelon geometry)on the plane.The faults have four kinematic characters:multi stage development,successive development,differential movement and transform movement.The fault belts formed abundant structural styles,helped hydrocarbon migration,improved reservoir petrophysical characters and controlled hydrocarbon distribution,they are very favorable for hydrocarbon accumulation and form major hydrocarbon pool types in the basin.Based on hydrocarbon exploration in the basin,more than 90% hydrocarbon pools are related to faults,mainly compresso wrench faults,and backthrust is the most favorable hydrocarbon accumulation among them.

There are two different seismic pattern recognition methods for prediction of hydrocarbon reservoir.One is statistical pattern recognition (SPR),the other is neural network pattern recognition(NNPR).In this paper,both methods are described with special attention to the analysis of decision interfaces.The decision interface of NNPR can be of any complex forms,while SPR can only have some simple decision interfaces,so NNPR is more adaptable than SPR.This conclusion has been proved by two examples.

The concept and method of sequence stratigraphy were applied to the reinterpretation of Palaeogene formation in the Jizhong depression.Having interpreted the seismic and drilling data,Palaeogene formation is divided into four sequences.Each sequence can be subdivided into three depositional system tracts:lowstand,transgression and highstand system tracts.The deposition of system tract or the distribution of lithofacies was controlled by both the water level (high or low)and the tectonic subsidence,so that each sequence consists of transgressive regressive sedimentary cycle. Having analysed the existing data,we know that the transgression system tract in Jizhong depression may be relating to "sea overflow" or "transgression",consists of thick dark mud shale layers with carbonate interbeds(including bioclastic limestone) and a great deal of microfossils relevant to a salt water environment.The microfossils were the main matter that became oil and gas.The favourable reservoirs are bottom fan,slope fan,slope channel sand body and transgressive delta in the lowstand tract beneath the transgression system tract,regressive delta and the fan delta sand body in highstand tract above transgression system tract.The trap type obviously depends on the generation type of sand body.

The Wenliu salt structure is localized above the central uplift in the northeast part of the Dongpu depression,Bohai Bay basin.The structure comprises downwards a simple crestal graben,a thickened salt core,and a basement horst.The structure was formed during the early of sha 3,stage of Eogene thick skinned extension.At an early stage,the salt layer partially decoupled deformation above and below the salt.The overburden formed forced fold that was cored with salt pillow above the central basement horst block.A graben formed at the crest of the forced anticline due to local arching.By the combination of regional extension and local stretching,the crestal graben widened and triggered reactive diapirism.Synkinematic sediments in the flank depressions caused salt to flow upward to the central basement uplift,which enhanced the rise of the Wenliu reactive salt diapir.As regional extension decreased,the reactive diapir ceased to rise and was buried by the Neogene and Quaternary sediments. We used scaled physical models of basement involved salt tectonics and salt dissolution to simulate the development of the Wenliu structure.The experiments reproduced the dynamic evolution of the Wenliu structure by regional,thick skinned extension.Conversely,salt dissolution had negligible influence on the formation of the simple Wenliu graben.

Integrative quantitative and qualitative research of preservation conditions of oil and gas pools are presented.The qualitative study includes cap rocks,faults,uplift and denudation,magmatic activity,time and space spans of source rocks,reservoirs and cap rocks,physical property of reservoirs and cap rocks,quality of source rocks,etc..The quantitative study consists of the modelling of dissipating quantity and accumulating quantity of oil and gas.Based on the study and contrast of the preservation conditions of four oil and gas pools,seven qualitative geological criterions and two quantitative evaluation parameters are posed,they are scientific basement for studying preservation conditions of oil and gas pools.

The geological risk analysis of trap and play is an important component of evaluation of exploration and development project,especially for the appraisal of pre drilling.Based on the study of the features of hydrocarbon occurrence and the mechanism of forming pool in trap and play, the steps of the geological risk analysis and the formula to calculate the chance of success for drilling targets are proposed.A new method and train of thought for the geological risk analysis of the trap and plays are put forward.

In view of the fact that there are some limitations when remaining oil saturation is determined by using resistivity log or nuclear log during the water drive period of a pool,the theory and method that remaining oil saturation of producing interval is estimated from Production Logging Data are presented and described systematically.A practical method is investigated by the relationship between remaining oil saturation and water cut established from combining data of relative permeability of core analyses with those of production performances of oil field.Field examples analyses demonstrate that the method has some advantages over conventional well logging methods,which include less influence of salinity of formation water,larger scope of investigation and better practicality.The method is more applicable to performance monitoring of remaining oil distribution in productive interval of water drive pool.

The effects of production rate,oil formation sedimentary rhythm,ratio of vertical to horizontal permeability,size and position of an impervious break,volume of edge and bottom water,ratio of oil to water viscosity,well spacing,perforation interval and capillary pressure on the production performace of a sandstone reservoir with bottom water were studied and analyzed with numerical simulation.The bottom water movement with impervious break in different vertical to horizontal permeability ratio were also simulated.The results indicated that the size and position of an impervious break,vertical to horizontal permeability ratio.oil to water mobility ratio and production rate are critical parameters that affect the water coning behavior in sandstone reservoirs with waterdrive.Water coning are not usually formed in sandstone reservoir with bottom water.

Fluvial reservoirs cover a fairly important proportion of production reserves. Areal continuity is a predominant factor that affects their heterogeneities,whieh also is essential for detailed reservoir description and modeling.In recent years,researchers made reservoir description and modelling by taking the technicl ues of outcrops investigation analogy. However,the application of outcrops analgy investigation is limited by the uncertainties of sedimentary environment and deposition condition. Based on the abundant static and dynamic state data,analysis of comprehensive utilization of sedimentary process sandbodies boundary,log curves and dynamic state were applied into subsurface study for detailed description of Fluvial in area. Discussion is facused on subdividing of genetic unit,microfacies study,recognition of sandbodies of single channels and detailed description of their continuites. The achivements provide successful experiences for geological study of reservoir modeling and residual oil study of old oilfield during EOR.

Using integrated source functions,new analytical solutions are presented in the form of Laplace transforms for horizontal wells bounded by two level planes in the vertical direction as well as two different regions in the perpendicular direction.Weakly feeding boundary conditions considered at these planes could involve the situation that one of the boundaries has a constant pressure while the others maintains a no flow boundary.The limit conditions at the composite interface include both circular no flow and constant pressure boundaries.The new solutions can be applied to not only drawdown,but also buildup tests of horizontal wells in a composite reservoir in which could exist either a gas cap or a bottom water.

The fluid flow of non-Newtonian power law fluids under the polymer flooding has been studied. Under the assumption of compound regions existing in a reservoir,a fluid model and the partial differential equations for pressure distribution have been proposed. The initial and three outer boundary conditions such as infinite. finite with constant pressure and closed boundary have been given according to polymer flooding in an oil field. The models of Newtonian flow in a compound reservoir,non-Newtonian power-law flow in a homogeneous reservoir and Newtonian and non-Newtonian compound reservoir are special cases. Well test models, their solutions in Laplace space and two special cases of two and three regions have been given. The relations between dimensionless pressure and time has been studied by using Stehfest numerical inversion. The method has been applied with two examples in this paper. This study can be used to predict formation permeability,skin factor and reservoir pressure with non-Newtonian such as polymer fluid flow and locate the polymer flooding frontier.

In this paper,a new model is established based on log normal distribution in probability statistics.This model may be used to predict production rate,recoverable reserves,annual maximum production rate and its occuring time of oil and gas fields.At the same time,the method of linear solution for the model is provided.Application of two oil fields indicate that the model and the method for solution are practical and efficient.

The simple and practical method to solve the Weng cycle parameters is proposed based upon the study of the Weng cycle,which needs only two times of a simple linear regression to get the results.This method can overcome the disadvantage of the complexities in solving the Weng cycle parameters and bring the convenience to the on site hydrocarbon reservoir engineers.It has practical significance and applied value.

After cement slurry is treated in magnetization,surface properties of cement particulates and electromotive propertied of colloid are changed and its netted texture is broken.As a result,cement slurry reduces its viscosity and shear force and has larger flowability,which is beneficial to improving displacement efficiency.Moreover,magnetic treatment accelerates hydration reaction speed of cement slurry and increases hydration products,so crystallization and precipitation are being perfected,cement stone is getting compacted.Because of permeability reduction and intensity increase,cement stone will plug and consolidate oil,gas and water layers better.In this paper,it is presented that the application mechanism on magnetization treatment of cement slurry through a seires of laboratory microexperiments.Magnetization treatment effect is expounded and proved.Through laboratory and oil field application,it is proved that cement slurry with magnetization treatment is a new technology of raising cement quality which possesses advantages of simple cementing practice,it invest a little with a high benefit.

Contour pattern of single screw hydraulic motors is not only composed of cycloid, but also can be composed of any convex curve. Either the curve of rotor or the curve of stator can be divided into two patrs, tooth top (tooth face) and tooth root (tooth flank). Only one of the four segments is independent. If one of the four is given and the demarcating point exists, other three segments are derivable. Any convex curve has its demarcating point provided, it is located far enough from the coordinate origin. Complying with the method discussed in this paper, curves derived satisfy the contour pattern condition. Contour patterns of cycloid are special cases of the conclusion of this paper.

The detailed field data is presented on the basis of failure criterion of 8(1/2)"XHP _3S rock bit, resulting in Life Distribution, Failure Rate Curve, Reliability Function and the empiric formula of wear versus life, reliability. A method of reliability calculation and the difference between idea reliability and practical reliability are presented. Those unconventional data are eliminated when studying the empiric formula. These jobs as well as the results are the first in and abroad.