Research and application of optimization method for injection and production well group parameters based on controlling waterflood front velocity
The water injection development of low permeability/tight reservoirs differs from that of medium-high permeability reservoirs.The unbalanced effectiveness of well groups leads to ineffective water injection,which is the main reason for low waterflood recovery.It is necessary to form a set of injection and production parameter adjustment methods with the goal of synchronous breakthroughs in oil wells to guide the on-site water injection adjustment.Combined with the actual situation of low permeability/tight reservoirs with mixed oil and water storage in Yanchang Oilfield,the authors established a mathematical model for waterflooding front of zonal radial flow considering the capillary force.A dual-end injection and production structure adjustment method was formed by optimizing the injection and production pressure difference and the water injection intensity.The authors quantitatively studied three key factors affecting the balanced waterflood of well groups.The results indicate that adjusting injection production well spacings and injection production pressure differences could effectively solve the problem of unbalanced planar waterflood caused by a large permeability ratio;when fw＜60％,the injection and production well spacing ratio has a significant impact on the well group recovery.When the permeability ratio is 20,the optimal injection and production well spacing ratio is 1.5～2.0 For mature development areas with fixed injection and production well patterns,the waterflood front velocity is mainly controlled by controlling the production pressure difference in each oil well direction.Based on the adjustment method of injection and production parameters at both ends,the injection intensity of injection wells in well group D4430-8 was increased from 1.87 m3/(d·m)to 2.50 m3/(d·m),and the injection and production pressure differences were changed by adjusting the pump setting depths in three oil wells.After the adjustment,the comprehensive water cut of well group D4430-8 decreased from 37.8％ to 25.29％,and the average daily oil production of a single well increased by 0.53 t,indicating a significant improvement in the waterflood development effect.The research results have important guiding significance for improving the plane sweep efficiency in the mature water injection development area of low-permeability and tight oil reservoirs.
injection and production parametersbalanced waterfloodnon piston two-phase waterfloodmathematical model of zonal radial flowlow-permeability and tight oil reservoirs
万方数据
维普
