The largest oil-productive base in China has been established in Bohai Bay Basin since its hydrocarbon discovery 40 years ago.Meanwhile,the theory on formation and distribution of oil-gas reservoirs in Tertiary rift has been completed a lot. It involves in multiple oil-gas-bearing structural sequences, multiple oil-gas accumulation zones,oil-gas reservoir types, trap boundary combination,oil-gas-bearing unit, and classification of petroleum exploration and evaluation stages and so forth. Exploration features and increase in reserve are obviously influenced by breakthroughs in frontier areas,and the application of theory and technology in exploration. So far,there are still many exploration frontier areas and great hydrocarbon potential in Bohai Bay Basin.

The composite petroliferous basin in China has long period of geological evolution history,multiple depositional sequences and intensive tectonic deformation. The petroleum system developed in this type of basin has some complex characteristics. One petroleum system commonly comprises several source layers or source kitchens,and experienced multiple periods of hydrocarbon generation,migration,accumulation and adjustment;hence the forming of hydrocarbon reservoirs might have several critical moments. Moreover, hydrocarbon fluid exchange often occur among systems through common migration paths,such as fault,unconformity,fissures created by over-pressured fluid,and lapped sand body,so that several source kitchens may charge a single reservoir. In accordance with the above complexity of the petroleum system in China,this paper introduced the concept of multi-source petroleum system, as well as its major characteristics, description methods and exploration techniques. A proposed research procedure starts with the description of the source kitchen,then following the nature process of hydrocarbon generation,migration and accumulation,focuses on the study of characteristics of geological elements and their combination at the critical moment, and the space of hydrocarbon migration and accumulation. The analyses of fluid migration history,basin simulation and the other modern exploration techniques played an important role in the description and evaluation of a multi-source petroleum system.

The marine origin gas pools in Tarim Basin are distributed in Tabei,Tazhong and Bachu uplifts. They have their respective characteristics on gas composition,phase and non-hydrocarbon composition.Analysis of three typical gas pools:gas condensate pool of Well Lunnan 59 Carboniferous and Well Tazhong 1 Ordovician and dry gas pool of Well Ma 4 Ordovician. Identified that all of the gas are generated from the cracking of Kerogen and crude oil.The three gas pool modes are built by comprehensive geological analysis: 1)the dry gas generated from cracking of Kerogen charged the paleo oil pool to form the gas condensate pool; 2)the cracking of oil to gas in paleo oil pool to form gas condensate pool and 3)the dry gas generated from cracking of oil to gas in paleo oil pools migrated to a new trap to form dry gas pool.

An extensional-shear fault system,which is not accordant with regional compression tectonic stress field,regularly developed during later Neogene in Mesozoic-Cenozoic formations in the northern area of Tabei uplift,Tarim Basin. It has controlled oil and gas accumulations and distributions in Cretaceous-Tertiary System in this area. On the basis of interpreted seismic data and regional geologic characteristics, this paper presents tectonic characteristics and the genetic mechanism of this fault system and its controlling on oil and gas accumulations in this area. The purposes of this paper are to make a better understand of this special fault system in Tarim Basin and direct petroleum exploration in the northern area of Tabei uplift.

Based on the characteristics of natural gas generation and distribution as well as the that of formation pressures in the east part of Sichuan Basin,migration and accumulation mechanism of natural gas in Silurian-Carboniferous petroleum system in the area is studied in the paper. There are two kinds of model for forming gas pools both in the abnormally pressured compartment and out the compartment in the system.After the breakage of overpressured fluid compartments in Silurian system,hydrocarbons generated in the compartments flowed to Carboniferous in a phase of mixed fluids. Within Carboniferous system, hydrocarbons migrated to the crest part of the existed uplift traps and formed primary oil and gas accumulation which then were changed into gas pools with their further buring. A large scale migration and accumulation took place during Later Himalayan movement,as a result a type of called remained gas pools with higher gas columns were formed. The water displacement experiment of Carboniferous gas showed that under normal pressure natural gas in subsurface reservoir is difficult to migrate into minor pores and displaced water out the pores in reservoir. Obviously this kind of gas reserved in minor pores migrated in early stage. The dissolution convection may be an important mechanism for the migration and ccumulation of gas pools.

The Cuoqin Basin is a large tectonic composite basin in Mesozoic Tethys tectonic domain. Its main part is located on Gangdisi-Nianqing -Tangula slab,including three tectonic-sedimentary units:northern downwarped zone, median slope zone,and southern magmatite zone. In Mesozoic era,the basin had different developing stages of primary rifting(T ₃-J ₁),peripheral foreland basin(J ₂-J ₃)and retroarc foreland basin(K ₁-K ₂).Thousands meters Mesozoic strata was developed in the northern downwarped zone. Upper Triassic and lower-middle Jurassic strata have metamorphosed near the Bangong lake-Nu river faults. These strata have good source-reservoir-seal assemblage far away the faults,maybe formed some hydrocarbon reservoir about thrust fold and overlap. Lower Cretaceous belong to retrograding sedimentary sequence of tide-flat-carbonate platform facies,and have good hydrocarbon source rock and reservoir rock but no good cap rock. Some little hydrocarbon reservoirs about thrust maybe formed near the Gaize-Nima faults and Jiangma-Geang lake faults.Cenozoic uplift of the Tibetan Plateau is main reason that huge oil-gas field like in the Persia Gulf Basin didn't form in the Cuoqin Basin.

In this paper result is reported of a primary investigation of the types of nonhydrocarbon in the heavy oil of Liaohe Basin, Northeast China,based on the analytical data achieved with GC and GC-MS of ten samples from the Leng-43 district,Niu-Xin-Tuo district, Gao-Ⅰ district and Gao-Ⅲdistrict respectively. The results show that the hetero-fraction of the samples is dominated by oxygenated compounds,while the abundance of nitrogenous compounds and sulphureous compounds is minor. No phosphorous compound was detected. The acidic fraction constitutes the main proportion of the oxygenated compounds(>47%),among which straight-chain fatty acids account for more than 96%. The insignificant proportion of the oxygenated compounds, however,consists of a variety of organic compound classes including straight-chain alkanones and alcohols,triterpanoid ketones and acids,sterols,iso-and anteiso-fatty acids,phenols and aromatic carboxylic acids. Besides,four pairs of isomers with unknown structure were outstandingly observed in the neutral fractionⅠ as main constituents. Additionally, a lot of compounds remain unidentifiable. The distribution pattern of oxygenated compounds imply that the heavy oil of Liaohe Basin has suffered strong biodegradation and underground-water flush,and received input of aquatic organisms of evident amount.

Undrilled formation pressure prediction is very complex. There are some methods available for predicting pressure,such as extrapolation by adjacent well,regional pressure analysis and seismic velocity spectrum analysis. But in oceanic area, some difficulties arise because of low well spacing density and limited information under serface. This paper introduced a new way to pressure prediction in undrilled formation by means of extrapolating sonic logging using artificial neural network while combining halfway log data with seismic data. This new technic and the procedure were presented in this paper. The extrapolating prediction for some oceanic wells in a area brought good result. It shows this research work is feasible and valuable.

Nearly two-thirds of all oil ever discovered onshore in China will remain in the reservoir at the conclusion of conventional oil recovery processing. As the ever increasing demand due to the rapid growth of national economy has continuous exceed supply,this massive quantity remains as a significant target for China's future oil production. Based on the first potentiality evaluation and experiences and lessons learned from the EOR applications in China,the strategy study and the second potentiality evaluation of EOR for 17 oil fields have been conducted. The results show that with the technology available at present,11.58 million tons of recoverable reserves can be increased. It accounts for 11% of 101.36 million tons of proven reserve evaluated. The study also attempts to determine the role that technology improvements will play in the future development of the remaining resource. It shows that the chemical flooding, especially polymer flooding,is demonstrateing great potential for application in China.The developing strategy and future planning for onshore oil fields in China are proposed on the basis of the evaluation.

Based on the results of laboratory, the incremental oil recovery of ASP (Alkaline-Surfactant-Polymer)-Foam flooding is 30% higher than that of the waterflooding. After the WAG injection in the same layer SⅢ3-7,the ASP-Foam flooding was conducted on Feb.24,1997.With the injection of ASP-Foam system, gas channeling has been controlled effectively,and foam was formed in the reservoir. Favorable effect has been achieved,the water cut decreased greatly in the two central wells,and obvious the oil bank has formed. Presently,the stage oil recovery is 10.64% in the whole pilot area,and is 10.34% in the central area.The total oil recovery is 54.96% in the central area. The ultimate oil recovery will be evaluated by core flooding,numerical simulation and performance of pilot test.

MEOR,with the advantage of low cost, no pollution and good economic benefit,is going to be one of the important techniques for enhancing oil recovery. The authors have selected and cultured a series of bacteria from crude oil, oil polluted water and sea water which they can decompose gum &asphaitenes of oil, increase light hydrocarbon components,endurance 80℃ and 300000mg/L salinity. The microbial cultures and selection methods were discussed and the bacteria treatments were made on the crude oil from Shengli, Liaohe and Qinghai in the laboratories and in the Qinghai Oil Field. After 24 hours treatments by bacteria group,the asphaltenes in Qinghai oil decreased 20%. Results from field tests indicated that after 20 days treatments by the bacteria group,the average daily output increased about 9% and well hot wash period extended 21 times.

By means of simulation experiments in sandstone micromodels,scaling mechanism and formation damage due to scaling of BaSO ₄ and CaCO ₃ are studied respectively. The results show:1)Formation scaling is formed in the repeated heterogeneous-phase nucleation and crystal growth. The crystal can grow both in pores and at throats. 2)The characteristics of scaling are different for different scales. BaSO ₄ scaling develops intermittently in the alternate process of water mixing and scaling, the morphology of the scale crystals develops poorly and the crystals are fine.While CaCO ₃ scaling develops continuously,the morpholgy of the scale crystals develops perfectly and the crystals are large. 3)The formation damage due to scaling is a complex problem,even if effects of temperature and multiphase flow are excluded,it is still affected by the amount of scale and formation permeability. In general,the larger the amount of scale is or the lower the permeability is, the severer the formation damage is. As the permeability of formation decreases, the difference of formation damage decreases due to different amount of scale. As the amount of scale increase, the difference of formation damage decreases in formations with different permeability.

According to the discrete material balance equation of control-volume,a new numerical scheme based on PEBI grid and CVFE grid is provided,where absolute permeability is in tensor form. Because of PEBI grid's orthogonalization,its discrete equation is similar with that of finite-difference method. The mobility coefficient and interface permeability can be calculated as same as finite-difference method. For CVFE grid,reduced pressure gradient is approximated using finite-difference and finite-element methods simultaneously,and a new upstream weighting approach is proposed based on the signal of flow term,which is more reasonable. The final discrete form of CVFE grid is different from that of PEBI grid and finite-difference method. Numerical model tests show that the method proposed by this paper is as accurate as nine-point finite-difference when permeability tensor is in diagonal form, and it can simulate more complicated cases when permeability is in full-tensor form. Its application prospect is more extensive in fine detailed reservoir simulation.

Changchun Oilfield is a weak volatile oil reservoir found in 1988. It belongs to faulted oil and gas pool. The oilfield adopted the policy of outer edge waterflood and high-speed development. The maximum production,which was 63.4×10 ⁴t in 1990, dropped to 7×10 ⁴t in 1994, and 2.85×10 ⁴t in 1999.The composite water cut changed from zero to 86.3%. The oilfield is now in the late stage of development. The features showed during the development resemble that in dissolved gas drive. Recovery efficiency is forecasted only 27%,23% lower than the ideal plan of numerical simulation. This paper expatiates the geological characteristic and types hydrocarbon's fluid in the oilfield and summarizes the course,features and experience in the oilfield development. It also concluded that the key issue for developing volatile oil reservoir and weak volatile oil reservoir is to keep reservoir pressure higher than saturation pressure. The importance of numerical simulation in the development of hydrocarbon reservoir is emphasized.

Sa、Pu、Gao formations of Xingbei area in Daqing Oil Field feature thin alternating beds of sand and clay in an onshore river and river delta complex. Each well in this area encountered a lot of layers. Not only the thickness and permeability between and in layers differ hundreds of times,there are also large differences in the development of various layers. Combined with the adjustment of pay zone and infill of well pattern, using plenty of logging data,detailed description of reservoir and thorough study of residual oil have been carried out since "The Eighth-Five Plan".A series of techniques of detail description on multi-well-reservoir of high water-cut period have been gradually developed. The application of these new techniques of adjustment oil field development achieved remarkable results.

This paper discusses methods used to estimate formation pressure in the scientific exploratory well. The optimum method was established for pressure calculation before,while and after drilling,which made the best use of geologic, seismic,logging, drilling,leak-off test,RFT and well kicks data,making the pressure calculation and analysis more systematic and more precise with each stage of drilling processes. The associated software package was developed to process formation pressure for practical wildcat planning and drilling. The difficulty of establishing accurate normal trend line was solved by recalculation and revision using RFT and well kicks data. MWD/LWD or log data was analyzed thoroughly to give as much information as possible for pressure calculating.Some models and methods for key parameters conversion (such as bulk density,shear wave velocity,shale contents and porosity both in permeale and impermeable formation)were developed in case of wanting, calculating from known measurements.

The basic principle and approach of Top Cement Pulsation(TCP) technology was introduced in the paper. According to the Newton's second law of motion, the law of conservation of mass,and Bingham plastic flow equation of slurry,as well as under top cement pulsation,the mathematical models of one dimensional pressure pulse propagation downwards in the cement column was established.At the same time, on the basis of elastic theory and liquid compressibility,the effective bulk elastic modulus under the joint action of wellbore rock,slurry and casing was derived.The physical meaning of TCP wave mathematical models and its concrete problems in applications were also discussed. It provides the mathematical models for the optimal design of top cement pulsation and parameters of compressor.

In view of the experimental results of seven plug-releasing technologies on 23 wells of certain recovery area in Daqing Oil Filed,this paper establishes an unascertained measure recognition model which synthetically evaluates, arranges and optimizes the effect of the seven plug-releasing technologies. The unascertained measure recognition model is strict in theory and the measure function is meticulously constructed. According to the sequence in dividing the evaluating space,the incredible recognition rule is established to replace the maximum subordinate recognition rule so as to reduce the misjudgment. In order to arrange the recognized object on good and bad order the score rule for sequence was established. Compared with such evaluation models as the fuzzy synthetic evaluation,gray classification analysis etc.,it has the advantages of high resolution and reasonable recognition. It is a practical model for optimization,recognition and synthetic evaluation. The author is mainly engaged in the research of unascertained information,esp.the methods dealing with the unascertained and mathematical model-set.

In this paper,a four order nonlinear differential equation with a parameter β, which describes the buckling deformation of pipes inhorizontal wells,is derived by using the principle of minimum potential energy and the variational method. Two bifurcation points (β ₁=1,β ₂=1.47) as well as the two critical buckling loads Fcrsand Fcrhare obtained and the three different types of bifurcation solutions are also analysized. When β<β ₁, the nonlinear equation has a zero solution,which is related to the stable state of the pipes. When β ₁≤β<β ₂, the equation has a peoriodic solution,which is related to the sinusoidal buckling state. And when β≥β ₂, it has a helix solution,which is related to the helical buckling state. The results obtained here are very important for correctly designing pipes and reasonably selecting working parameters in horizontal well drilling,completing and stimulating operations.

There are many existing methods for well trajectory design while drilling,which include two-dimensional and three-dimensional methods. They have a common shortcoming that the designed well trajectory is not sure to be an optimized or a possible optimized trajectory. The paper introduces the nonlinear programming method under nonlinear constraints to well trajectory design while drilling and puts forward an optimization method for well trajectory design. The method can not only satisfy the oilfield construction condition and the well trajectory design while drilling, but also assure the designed well trajectory to be the most slip,the shortest and possible optimized well trajectory. The example in the end of the paper shows the method is right and reliable.

Presently,there is no concept of perforating azimuth angle in perforating design and perforating practice. But,perforating depth of shot will decrease along with increase of intensity and density of stratum,furthermore,stratum resistance to shot will increase following as increasing of intensity and density of rock according as theory of shock wave. At same times,as we know, distributing of stress of stratum around wall of a well is difference due to difference of magnitude and direction of tectonic stress. So,we can educe that perforating azimuth angle has an import effect on actual perforating depth of shot. The author primarily probe into choosing of optimal-perforating-azimuth angle in the light of distributing status of stress around well in perforating depth,define the best stress coefficient and worst stress coefficient.

Bohai Sea is the first explored area in China Offshore and first oil discovery had been gained from the shallow targets. After a long-term exploration and development,the mechanism of hydrocarbon accumula-tion at shallow targets is nuderstood. Up to date the reserves discovered at shallow targets has exceeded 70% of total in Bohai Sea. Neotectonism (Bohai movement)is characterized by:(1)different Q and N center of sub-sidence,and angular unconformity between Q and N;(2)basalt effusion and magma activities frequently;(3) regular distribution of earthquake center;(4) intensive later faults(15-2Ma)forming multitude anticiline in Nm-Ng formations. In accordance to kinetic analysis of tectognesis,neotectonism was caused by mantle rise, plate movements and Tanlu faults,and it controlled the late hydrocarbon accumulation in Bohai Sea. Bohai Sea will play an important role in stabilizing oil and gas production in the eastern China.

Bohai Bay Basin is divided into onshore and offshore parts. In onshore gas exploration,only few small gas fields have been found up to now,mainly with associated gas. But in the offshore,gas exploration has taken good effect. Compared with the onshore, offshore Bohai has better geological conditions for forming gas pools,there is much better exploration potential in the offshore. The factors responsible for the gas rich-ness in offshore Bohai are represented as follows:The thicker deposition sediments, it made the main source rock-Eocene Shahejie Formation reach overmature to generate gas;there is huge thickness of Oligocene source rock-Dongying Formation; there are strong Tertiary tectonic movements and high heat-flow in the offshore. In addition,the shallow layer is also a gas exploration area in the offshore.

Bohai area is in the east part of Bohai Bay Basin,and experienced rifting,transfer and post-riling phases in Tertiary. Half graben and half horsts are the basic units during rifting phase. According to the oritntation and dip of boundary faults between half graben and half hoist, there were three groups of half graben in Bohai and nearby area,the first occurred in its south-western part (Huanghua Depression),most of half graben's bonudary faults dipped eastwards;the second happened in its middle and south area (Chengning uplift and Jiyang Depression and south part in Bohai area),most of graben boundary faults dip southwards;the third in its northeastern area (Liaohe Depression, and northeast Bohai),most of half graben boundary faults dip westwards. In the transfer phase between rifting and post-rifting,thick strata of Dongying Formation formed in Bozhong and Qikou Sags (overstacked on Bozhong half graben and Qikou half graben),and horsts begun subsided during this phase. Post-rifting mainly occurred in Miocene and Pliocene and Quaternary, and formed Guantao,Minghuazhan and Pingyuan Formations. During the whole evolution,subsidence and sedimentary center migrated from southwest to Qikou Sag for south-west belt and from Damingtun Sag in northeast and Changwei Sag in southeast to Bozhong Sag respectively. All these phenomena show Bohai area is a pull-apart basin involved mantle activity in Tertiary. Many rich source-rock half grabens formed during pullapart rifting,and lower part Dongying formed in transfer phase is potential. In Quaternary Bohai area was inverted by Tanlou movement,and formed a lot of traps in Bozhong area,particully along east part of Bozhong Depression. We here named the movement as "Bohai Movement".Controlled by tectonic history,there are three kinds of local background for trap development, those over horsts,along horsts and in sag.

This paper points out distinctly for the first time that Laizhouwan Sag is a pull-apart sub-basin that is related to the strike-slipping of Yingkou-Weifang fault in the Cenozoic. Yingkou-Weifang fault is a segment of Tan-Lu fault system,we estimate its wrench displacement in the Cenozoic is about 40km. Utilizing balance cross section technique,we calculated the pull-apart extensional length in Laizhouwan Sag is about 5～7km,extensional rate is about 2000. Further more,based on the analyses of the characteristics of fault development and the subsidence history,we find that Laizhouwan Sag had been experienced three structural evolution stages-those were the initial strong rifting stag during Eocene,the tender rifting but stronger down-warp subsidence stag during Oligocene and the tectonic rejuvenation stage under the background of thermal subsidence during Neogene. Finally,the continental pull-apart extension model in the study area has been disussed. And also points out that the strike-slip belts on the eastern and western sides of the sag and the central structure belt in the sag are the good oil and gas potential exploration zones.

This text is based on the exploration achievement of near 40 years and the data analysis of more than one hundred drilled traps on in Bohai. The characteristics of oil fields and oil-bearing structures have been studied. The relationships between the characteristic of hydrocarbon reservoir and the action of fault system have been discussed in Bohai. It is found that the draping anticline on salient and the wrench-compression anticline on low salient are the most valid type of hydrocarbon-bearing pool. Both Neogene Guantao and Minghuazhen Formations are major oil-bearing series and Paleogene Dongying Formation and Shahejie 1&2 member are secondary ones. The distinctive history of basin developing and especially Neogene Tan-Lu fault system activated strongly again affected the formation of hydrocarbon reservoir significantly in Bohai.

Several big oil-gas reservoirs,with reserves of 100 million tons more,have been discovered in the Upper Tertiary middle and shallow strata of Bozhong area in Bohai Bay since last five years, as a result,the area became the hot-point area followed with interest by domestic and abroad oil men. Bozhong area has different oil-gas accumulation characteristics from the adjacent onshore oil fields. Because of the latter thermal event and tectonic action,Bozhong area became the subsidence center and depo-center of the Bohai Bay Basin. There is better reservoir-seal formation which is superior to the adjacent oil field onshore,the latter fault action timing with the big scale hydrocarbon migration provided the favorable conditions for oil-gas migration and accumulation toward Upper Tertiary trap. Many kinds of reservoir-forming model created many kinds of oil-gas reservoir,two kinds of fault structural system and the tectonic framework of horst-graben interval are favorable of the oil-gas rich accumulation toward middle-shallow strata and uplift area. Therefore the Upper Tertiary middle and shallow strata are major exploration zone.

Bozhong Depression with vastly thick Tertiary System deposit underwent two evolution stages of structure-deposit: rifting stage and post-rifting depression stage. In the rifting stage three sets of hydrocarbon rocks of Sha-IQ,Sha-I,and Lower Dongying Formation were developed,being of very good hydrocarbon-generating potential developed. The depression contains very rich oil and gas resources. The deposit of fluvial plain facies,developing the braided stream to meandering stream and nearshore shallow lacustrine sedimentary system, characterizes the Neogene post-rifting down-warping stage of Bozhong Depression. There are two sets of reservoir-seal assemblages generated in the Neogene system:one is composed of the mudstones of fluvial-lacustrine-marsh to shallow lacustrine facies and the thick-layer sandstone of Guantao Formation,being a very favorable regional reservoir-seal assemblage;the other is a interbedding reservoir-seal assemblage consisting of overflooding plain mudstone and the sandstone of meandering stream. These two sets of assemblages provide a very favorable condition for the oil and gas accumulation in the middle to shallow layer of Bozhong Depression.

The Lower Dongying Formation exists a source rocks with relatively high concentration of organic matter and good organic type,especially, most of them are good and excellent,and they are very thick. For more important, these source rocks are locating in oil window. But,their distribution is not homogeneous,the southern part of the depression is better than the north, the eastern part of the depression is better than the west. The distribution of oils derived from the Dongying source rocks is conformed with the distribution of the lower Dongying source rocks.

This paper,based on condensate gas reservoir characteristics, presents a method for determining the law of condensate distribution and predicting condensate gas well's optimum output. The first,the combination with condensate gas filtration characteristics has built and inferred in detail the unsteady filtering equation in porous medium. By using the two-phase pseudo-pressure function of condensate oil-gas,the pressure distribution equations have been fetched for three kinds of typical boundaries in condensate gas reservoir,that is,an infinite outer boundary,a finite closed boundary and finite boundary with the constant pressure. And has built the relations between pressure and pseudo-pressure,and the law distributed condensate oil content,when gas well is producing from the reservoir. Using the data of the condensate content change with pressure in constant-temperature,the distributive characterization is defined under producing. Under drawing Inflow Performance Relationship Curve (IPRC)of condensate gas well is considered the curve's reliability. Some important behavior factors are obtained by using the steady-test data of gas well. To combine IPRC of gas well with the distribution condition of condensate content in formation,the condensate gas well's optimum output is selected. By means of example well A,combination this paper presented theory with the method,the method has systematically provided for defining condensate gas well's IPRC and optimum output.

The information and results of MEOR study and application have been compiled in this paper. In China,great progress have been achieved on research of strains and mechanism in laboratory,many kinds of formation have been candidates as field pilots to conduct microbial treatment or microbial enhanced waterflooding. The results show microorganism can increase oil production and decrease water cut. The technology of MEOR will become an important method in improving oil recovery in China.

The precise survey technique of geochemical exploration is a new technique that recently developed for oil field's exploration. In the basis of knowing the rules of regional geochemistry, studying the characteristics of near surface geochemical effect in discovered field,knowledge about the stratum and liquid's chemical property in different periods were obtained. In the mean time,with the help of high density regulation surveying web various methods were applied to detect the components of reservoirs and the vertical micro-migration traces of the oil and gas. These methods respectively use synthetic hydrocarbon gas (dissociate hydrocarbon,adsorptive hydrocarbon,subsistent hydrocarbon,water-dissolved hydrocarbon,high-carbon hydrocarbon),light aromatic hydrocarbon and isotope. In data processing, polybasic statistics and geological statistics were combined to acquire information in concentration lining degree, structure, fabric and analogism. At the same time,anomalous boundary was determined by simulation and the quantitative evaluation method for geochemical exploration anomalies was also discussed. The precise survey technique can specify the range of oil field,give the extension direction of discovered oil fields and provide the scientific basis for drilling production wells and exploration wells.

Since the crude oil in our country has the higher waxy content and has the outstanding thixotropic property,the study on the flow of the thixotropic fluid was very important for the petroleum industry in our country. In this paper, using the Moore's thixotropic fluid constitutive equations which was a non-elastic fluid model,two representive flows in petroleum industry were discussed. One was the laminar flow in the pipe (also called the Poiseuille flow). The analytic form of the relationship between the flow rate and the pressure gradient along the pipeline was obtained. It was very complicated and has the non-linear form. For the convenience in analyzing some problems in the pipeline transportation of the crude oil,an approximate formation of the analytic form was also provided. The other was the flow in porous media, which was the theoretical basis for analyzing the flow of the crude oil in the stratum. The equations on the flow in porous media was provided for the Moore's fluid,and the analytic solution on the plane radial flow in porous media was obtained,which the theoretical basis for accurately estimating the pressure distributions in the recover petroleum.

Annual and monthly measurement rate is the gray original character systems influenced by multifactor. Multinomial forecast model,assembled forecast model and GM(1. 1)forecast model of measurement rate is proposed according to the basic principle of gray theory. The established forecast model of mutation monotone or nomonotone initial sequence adjusted by residual error amendment and period amendment several times. Fewer errors are found between the forecast and true production. The quantificational forecast model is adjusted to accord with the reality of the comprehensive application of many types of models at actual computation. The situation that forecasting measurement rate only relies on experience in the past is changed. It is a kind of scientific, practical and maneuverable method and it has been proved to be feasible by actual examples.

This paper presents an intelligent application system of building distance drilling multi-specialist cooperative guidance,which is used to implement the idea and the concept of distance drilling based on network cooperative work. This method uses the modern computer science and net communication technology. Orienting petroleum drilling and gathering geological exploration and development together,studies and develops an intelligent application system which is supported by powerful petroleum engineering database,multi-specialist,software,group cooperative work and real time instruction. This method makes it possible to change the drilling work mode,span terrain barrier,breakthrough the limitation of time and implement distance drilling based on network cooperative work. This paper mainly analyzes and discusses the each aspect of method and technology,and draws the outline of the basic rudiment of the intelligent system.

As the development of petroleum industry and progress of science ＆ technology, drilling technique will enter into a new phase of artificial intelligence drilling. The artificial intelligence and its two important branch-expert system and intelligence control for drilling engineering are introduced in this paper. It also rasises the concept and content of artificial intelligence drilling. According to the realities of drilling engineering,it provides a new Real-Time Expert Intelligence Control System (RTEICS). In combination with the advantage of traditional expert system and intelligence control it constructs an integrated artificial intelligence drilling system. The following are involved in the paper:principle and constitution of RTEICS;interface modes of expert system and control system. Furthermore it discusses details important to be solved in the RTEICS-real-time processing,stability,reliability,self-learning ability etc. In addition,it shows the prospects of artificial intelligence drilling for the twenty-first century.

A type of pumping unit with the auxiliary linkage and wheels is introduced in this paper for stroke increasing. In light of its mechanism,the analyses of working loasds and calculation of stroke are conducted,and the formulas are derived for calculating the factors of force increasing and stroke increasing. Then,the solid models of all components in the pumping unit system are created,and an assembly system is configured.Next the computer simulations of kinematics for it are conducted in I-DEAS environment,and some curves for describing kinetic characteristics of pumping unit are obtained. From this,the working loads are created by means of simulation method,and some curves for describing the loads exerted on main joints and driving torque exerted on crank are plotted. Finally,these curves are analyzed and the reasonable counterbalance ways and the mass of counterweight are determined.

An oilfield water flooding pipeline network is a large-scale fluid network system. Conventional model calculation method is time-consuming and has greatly hindered the development of simulation and optimization of an oilfield water flooding system. On the base of analysis,two methods are given in this paper. One is the model simplification technology which reduces identity matrix K dimension considerably, and the other is the improved iteration method which reduces the amount of calculating work from n' to n. A calculating software about a large-scale oilfield pipeling network is created by the use of the two methods. The result indicates that on the premise that the calculating accuracy is met,the model calculating speed is enhanced extremely. The technology has been applied to oilfield flooding system and received high ratings.

It is well known that the design of equipment capacities has significant influences on the equipment investment and furthermore on the economy of the thermal recovery process of heavy oil because the oil production depends greatly on time. In this paper a new mathematical model for determining the economical equipment capacity of the heavy oil thermal recovery system is proposed. First of all,the variation of the production data was investigated with statistics based on the recorded production data. It was found that the equipment capacity gap,namely the difference between the averaged liquid production of the thermal recovery system and the corresponding equipment capacity, dominantly affects the economy of the production process. Then a mathematical relation between the equipment capacity and the equipment capacity gap was derived.Finally a theoretical economic limit was proposed, correlated with the equipment capacity,the variation of the liquid production of the system,the mean oil price and the equipment investment.

The systematical structure and operation principle of a welding seam anti-corrosion applicator inpipe robot for water injection pipeline with cement mortar liner in oilfield is introduced briefly,the physical model of cement mortar by screw conveying is set up on the basis of its rheology,then screw conveying mechanism of cement mortar when being conveyed by operation unite of the in-pipe robot is analyzed,by introducing the concept of screw conveying efficiency,the quantitative calculation of cement mortar being conveyed by screw conveyor is solved,as a result,that makes the accurate quantitative control for cement mortar through screw conveying feasible when robot mending the welding seem by harmonious operation,the quality of the mending operation is guaranteed,the experiments show the rightness of the theoretical analysis,this robot has already been found its application in Daqing Oil Field.