Unstable Water Injection Experiments And Parameters Optimization Design In Heterogeneity Reservoir

This paper aims at the optimization design of parameters influenced the effect of unstable water injection. Laboratory experiment and numerical simulation are conducted to research the factors affect the recovery of unstable water injection on the base of deep analyze of present situation both at home and abroad.First, on the research of laboratory experiment. The single-phase drive experiment of micro heterogeneity model proved that recovery of unstable water injection is better than conventional injection, and the different of oil viscosity and injection parameters can influence the effect of unstable water injection. On the simulation experiment study of inner longitudinal heterogeneity reservoir, when the drive turn into unstable water injection, it is found that the lower reservoirs have"suck-back"phenomenon at the stage of reducing injection, for the stronger heterogeneous reservoir, it is better to use earlier unstable injection, for the weaker heterogeneous reservoir, the effect of later is better, under the same heterogeneity, the greater fluctuations of water injection, the higher the degree of recovery,the smaller relative frequency of injection, the better the results.Secondly, the 12 parameters that affect the effect of instability waterflood are selected, which consist of geological factors and development factors. Each parameter take 3 levels to conduct the orthogonal test design of numerical simulation. Every program of the tatal 27 groups test program is conducted in ways of conventional water injection and unstable water injection respectively in the premise of injection-production balance. The examines index is the difference between unstable and conventional water injection for improve oil recovery. We judge the relations between the primary and secondary factors of affect examines index by the intuitive extremedifference analysis method. Get parameters on test results significantly affected by variance analysis method. Then, ensure the best solutions of unstable injection to improve oil recovery; and verify its effect.Thirdly, this papers deepened the microscopic mechanism of unstable water injection, which based on the research achievement of the laboratory experimental and orthogonal test design of numerical simulation, and analyzed the geological and development factors how affecting unstable waterflood effect. Finally, It confirmed redevelopment object of unstable water injection, cleared application condition and feasibility analysis, and implementation. For the frist time, this paper puts forward the principle of water injection parameters optimization design method.