Application of Optimization Method Based on Water Flooding Law in Edge and Bottom Water Reservoirs

Abstract

D_F oilfield is a reservoir with strong edge and bottom water. It has been developed for 40 years by natural water flooding and artificial water injection. At present, the comprehensive water cut is 96.3%. In order to make full use of natural energy and improve development efficiency, this paper establishes the function of formation pressure, injection-production ratio, liquid production and water cut by improving the characteristic curve of type A water drive, comparing dimensionless liquid production index, simplifying material balance equation, and taking this as a constraint, establishes the optimal objective function, and optimizes injection-production ratio, liquid production and other injection-production parameters by using stochastic approximation method. The results show that according to the analysis of production characteristics of D-F edge and bottom water reservoir, the basic parameters of constraint functions such as water drive characteristic curve and material balance equation are fitted. By using stochastic approximation method, the annual production of D-F reservoir is 112 million barrels and injection-production ratio is 0.65. The economic benefit of D-F reservoir is the best. The results are basically consistent with the results of numerical simulation optimization, which proves that the method is reliable and can be used for collaborative injection and production optimization in the middle and later stages of edge and bottom water reservoir development. This paper innovatively establishes an optimization model with improved water drive characteristic curve and material balance equation as constraints and economic net present value as objectives. The injection-production parameters such as injection-production ratio and liquid yield can be optimized by improving the characteristic curve of type A water drive and constructing the optimal model of water drive law constraint, which provides an efficient method for the collaborative injection-production optimization in the middle and later stages of the development of edge-bottom water reservoirs.