Studying On Hydrocarbon Accumulation And Developing Simulation Based On Fluid Potential

The Carboniferous in Donghetang area in northern Tarim Basin is an important reservoir,and researchers have found Donghe 1 Oilfield and a series of Donghe sandstone reservoir in outlying areas.The study that the oil and gas accumulating rules in the unconformity is not fully understood,the distribution of the dominant filling channel of oil and gas is the main problem at present.It hinders the deepening oil and gas exploration and development in Donghe sandstone in the area and is a major problem.At the same time,reservoir which have been found have entered the later stage of development,preferential percolation path is developed in the reservoir,this has a great influence on the later development of reservoir.Therefore,how to identify and predict the reservoir percolation channel during the development period is an urgent problem to be solved in the middle and later stage of oil field development.In this paper,based on the basic theory of stratigraphic unconformity body,the structure of unconformity body in Donghe sandstone is anatomized.It is proposed that the Donghe sandstone is an unconformity complex formed by the unconformity between the top and the bottom of the Donghe sandstone.Based on the theory of net blanket accumulation,the unconformity complex reservoir system is divided into the upper layer,the lower layer hydrocarbon accumulation combination and the combination of upper and lower layer types.The net blanket accumulation characteristics of Donghe sandstone are summarized,oil and gas source is from other formation,the storage layer and the gathering network layer is developed.The Donghe sandstone reservoir is divided into tectonic unconformity composite reservoir,lithologic fault composite reservoir and stratigraphic unconformity screened reservoir.And they are controlled by unconformity complex and structure.Based on the basic theory of fluid potential model,the fluid potential in accumulation is divided into potential energy,pressure energy,kinetic energy and interfacial energy.Based on the Darcy's law,we established the fluid potential characterization model in the original state,the natural energy exploitation stage,water flooding development stage and late stage of water flooding development.The establishment of reservoir fluid potential characterization technique is established.By using the method of well seismic combination potential energy can be characterized;Based on the Wiley's model by using logging data,the pressure energy of the given well can be estimated,based on the model of Philip using seismic data,the formation pressure can be calculated,in the end we use the well datas to correct the seismic data to calculate the pressure energy;Seismic wave impedance data and logging data is used in the investigation of porosity,pore throat radius and other parameters,so as to achieve the purpose of characterization of interfacial energy;As the fluid flowing speed is low in accumulation stage,kinetic energy is negligible.On the basis of the established development potential model,the characterization software of fluid potential in middle-high permeability reservoir is developed based on QT platform.This paper presents the ant colony algorithm simulation method of oil and gas reservoir filling,oil and gas development based on fluid potential.The simulation of injection and development based on ant colony algorithm is realized.Based on the fluid potential characterization results and using ant colony algorithm methods,we simulate the injection preferential percolation path distribution in unconformity complex level,single reservoir plane,single reservoir profile,summarizes the distribution characteristics of preferential percolation path in unconformity complex and inner reservoir.The results show that the oil and gas in the filling process presents the characteristics of heterogeneous injection,the oil and gas in the unconformity complex is preferentially injected into the low potential zone,and the oil and gas in the reservoir plane and section are filled with a low vertical potential layer and a low potential region on the plane.The fluid potential distribution during development is characterized,and preferential percolation path in plane and profile is simulated.The preferential percolation path in the plane is distributed in the dominant rock facies.The coupling effect of preferential percolation path in oil and gas injection and development in reservoir is summarized.The preferential percolation path in plane is formed mainly in 2-2,3-1 and 3-2 layer,the preferential percolation path in surface is formed mainly in the original delta river branch,transformed estuary sand dam.This method can be used as a guide for the early prediction of the dominant preferential percolation path in oil field development.At the same time,it has certain reference significance in exploration well deployment.