Developing a new technique for the simultaneous optimization of both segmented time and injection rate for water flooding reservoirs: An analysis of Shengli Oilfield XIN-42 reservoir block

Yinfei Ma,Baoguo Tan,Anfeng Shi,Hongxia Sun,Xiaohong Wang

doi:10.1177/0144598720925557

Abstract

The adjustment and control of the water injection rate is a commonly used method for increasing the cumulative oil production of waterflooded reservoirs. This article studies the production optimization problem under the condition of a fixed total water injection rate. The production process is divided into several segments. Considering the correlation between the segment’s time intervals and the well’s injection rate distribution, a simultaneous optimization of both segmented time and injection rate is proposed for enhancing net present value. Both empirical simulations and field application demonstrate that the suggested methods produce the highest increase in net present value – of approximately 13% and 10%, respectively – and significantly improve water flooding efficiency compared to other conventional schemes, such as segmented oil production optimization, cumulative oil production optimization and Bang-Bang control. The proposed methods under a 2-segment division increase oil production efficiency and greatly reduce adjustment costs.

Highlights

With the development of digitized and intelligent oilfields, optimization methods for oil extraction are currently receiving significant attention (Aitokhuehi and Durlofsky, 2005; Brouwer and Jansen, 2002; Brouwer et al, 2004; Hasan et al, 2009; Izadmehr et al, 2018; Jansen et al, 2009; Lin et al, 2019; Oliveira and Reynolds, 2014)
It is indicated that the simultaneous optimization of both segmented time and injection rate provides the highest net present value (NPV) among the six adjustment schemes
For Bang-Bang control optimization, both the 2-segment scheme and the 4-segment scheme produce an 11.49% increase in NPV. This demonstrates that simultaneous optimization methods can be sufficient to stimulate the NPV in the conceptual model

Summary

Introduction

With the development of digitized and intelligent oilfields, optimization methods for oil extraction are currently receiving significant attention (Aitokhuehi and Durlofsky, 2005; Brouwer and Jansen, 2002; Brouwer et al, 2004; Hasan et al, 2009; Izadmehr et al, 2018; Jansen et al, 2009; Lin et al, 2019; Oliveira and Reynolds, 2014). The adjustment and control of water injection or fluid production rates is a primary method of increasing oil production. Asheim (1988) studies the optimization problem of the water injection rate without dividing the production process into segments, such that the injection rate of each well remains unchanged across the entire production process. The optimal injection rates for different wells are calculated using the gradient method. Asheim finds that using optimization methods without dividing production processes lowers the efficiency of oil extraction. Van Essen et al (2010) determine that without segmentation, the water phase will not adequately prime the production wells and, in certain regions, the oil phase will not be fully completed, thereby causing poor sweeping efficiency Asheim finds that using optimization methods without dividing production processes lowers the efficiency of oil extraction. Van Essen et al (2010) determine that without segmentation, the water phase will not adequately prime the production wells and, in certain regions, the oil phase will not be fully completed, thereby causing poor sweeping efficiency

Methods

Results

Conclusion