Evaluation Of The Effect About Horizontal Well Gas Flooding Based On Internal Architecture Structure Of Sand Body In Extra-low Permeability Reservoir

The rational exploitation of oil and gas fields is a very important task in the oil industry.There is a clear unsuitability for the application of the exploration and development method of low permeability reservoirs to extra-low permeability reservoirs. The development method of water injection and gas injection is not obvious,caused by the lack of internal structure and the remaining oil distribution model,and it is a very common problem in the extra-low permeability reservoir development area. Therefore,it is very necessary to study the horizontal well gas drive project based on the internal architecture structure of the sand body and the remaining oil distribution model.The development area of Dong 141 is a typical extra-low permeability reservoir.Accord-ing to the geological conditions of the study area, we established the logging facies model,and summarized that the main sedimentary facies of the study area are meandering river facies by the plane combination technique.In this paper.The YI6-YI7 sand group in the Dong 141 area is the research object.The fine internal architecture structure of the meandering river point bar sand body is studied, and got the tendency of the inner layer of the point bar sand body,the dip angle,the plane distribution and the density of the inner layer.According to the internal configuration parameters of point bar sand body,the establishment of three-dimensional geological model with high precision by using Petrel software, and based on the characteristi-cs of reservoir configuration,the core data from horizontal well and oilfield production data,we got the three distribution models of remaining oil in the study area.On this basis,the Eclipse software is used to complete the water flooding history of the study area,to further modify the three-dimensional geological model,and to establish the initial parameters of numerical simulation.For the horizontal well injection of CO₂ in the study area driving breakthrough rapidly,we designed different projects of CO₂ gas flooding, and used the numerical simulation to complete the simulation.Based on the well network of 3 horizontal wellsand 3 vertical wells combined,using CO₂ foam displacement method, gas injection amount was 150t.The injection production ratio is 1.3:1.CO₂ injection for 5 years, 5 years later to water flooding, until the water content reached 99%.Comprehensive evaluation of recovery compared with water flooding increased by 12.2%.It provided strong support for the study area next step about CO₂ flooding project design and implementation.