Study On Water Injection Development Mode Of Low Permeability And Compact Reservoir

In China, low permeability reservoirs have account for more than half of the newly discovered oil and gas fields. Only in2008, crude oil of low permeability reservoirs accounted for37.6present of total oil production, and natural gas production which accounted for42.1percent of natural gas production. Obviously, the low permeability reservoir has become the main battlefield of the development of oil and gas. As we know, water injection to this kind of reservoirs is one of the most effective and economical ways to improve oil recovery. However, due to different geological conditions in various fields, in what type of mining or how to inject water in order to achieve the best development result is always an issue of concern. So study of water injection in low permeability reservoir is of great significance.The study is based on the Sichuan Basin oilfield Daanzhai Gongshanmiao dense low permeability reservoir, with the integrated use of knowledge seepage mechanics, reservoir engineering, numerical simulation to study dense low permeability reservoir capacity curve and optimize water injection methods. The main contents are as follows:(1) Derived vertical, horizontal and fractured horizontal well productivity mathematic model using Laplace transform and Superposition principle; drawn transient flow type curves of oil wells rate with C#;(2) Established a mechanistic model to analyze the skin factor, anisotropy coefficient, connection factor, horizontal well length, fracture half length and other factors on productivity with the use of Eclipse;(3) Simulated18kinds of well patterns with the use of orthogonal analysis; determined the optimal injection development well pattern by comparing the cumulative oil production;(4) Optimized the water injection parameters (water injection time, water injection rate, water injection ways) with the test block; compared the production curves calculated by production mathematic model and numerical simulation, the results show that two calculated results fit well;(5) History matched the total reserves and pressure of five wells in Gong39blocks; deployed well pattern and calculated total oil recovery.The pattern has been used to guide the development of the block, and practice has proved that this water injection method has achieved good results. It significantly improved the oil recovery of blocks. The research has a guidance and reference for the development of similar reservoirs.