Exploitation Indexes Forecast Of Low-permeability Of Immiscible Hydrocarbon Flooding Reservoir

Shengnan test site is the research aim of this paper. Reservoir geology and development feature are investgated in detail. Shengnan test site is a lithology-cut reservoir. It includes bottom-water. There are several characters of development in sector when water flooding, such as, taking effect slowly, descending fast at oil rate and formation pressure, upswing fast at water cut. The author utilizes the geology and development feature data of Shengan to match it's history of water flooding, and forecast the result of gas injection by CMC. It's include two method for natural gas flooding: miscible flooding and immiscible flooding. The MMP was measured and analysised in lab. Because the MMP of natural gas is far larger than the formation pressure, it only can be immiscible flooding in Shengnan test site.At first, the author expounds the mechanic of gas flooding, and lots of phisical chemistry phenomenons, molecule diffusion and micro-convection current, gravity and capillary force, startup pressure, and so on. Through lab experimentation, the relationships of startup pressure gradient and permeability, startup pressure gradient and viscosity are obtained. The startup pressure gradient decreases when permeability is up and upswings when viscosity of oil is up. By the lab experimentation of long core, kind of production indexes of natural gas flooding are obtained, and the formula for calculation are regressive.On the base of geology character and mechanic of gas injection, the geology model and math model of immiscible gas flooding are set up, and one demension analytical solution is come by. Compiling one programme, the author applies one set of data of test site to it for production indexes calculation, and apply the data to CMG also. The result show it's samililar. The new maths model can be apply to forecasting of line drive gas injection, and can be popularized to five-spot and other areal well pattern.This paper is instructive for low and special low permeability reservoir to predict the porfermance of gas injection.