Optimization Design for Conformance Control Based on Profile Modification Treatments of Multiple Injectors in a Reservoir

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractWithin the past 40 years, profile modification has been widely used in China to control excess water production and improve waterflood sweep efficiency. As most reservoirs reach mature stage, single well treatment often becomes uneconomic. Therefore, profile modification treatments of multiple injectors based on reservoir scale have been applied to improve reservoir conformance. In this paper, a method is introduced to optimize the design of the treatment. The selection of the wells and target layers, as well as the chemical agent and injection parameters can be achieved by this method. The selection of candidate wells is based on fuzzy mathematics methods, considering well injectivity, reservoir heterogeneity and offset production well performance. The chemical agent is selected from over 40 formula commonly used in China, according to its compatibility with reservoir characteristics and well injectivity. The volume of treatment is optimized by running numerical simulations. This optimization method has been widely used in many oilfields in China. In most cases, production analysis after treatment shows that the waterflood efficiency is improved, and that the model predictions match well with the actual production data. As an example, a detailed analysis of the treatment performed in the Long 11 fault-block reservoir in Qing Long Tai oilfield is given in the paper.

Predicting injection profiles using ANFIS

“…Soft computing methods have been widely applied in many areas in the petroleum industry, such as reservoir description [27], well logging interpretation [16], production prediction [29] and treatment optimization [17]. In this paper, two neuro-fuzzy systems, ANFIS-GRID and ANFIS-SUB, are employed to model the relationships of injection profiles and their influential parameters.…”

Applied Technologies and Prospects of Conformance Control Treatments in China

“…The key to successfully apply the technology is how effectively to select multiple candidates from multiple injection wells. Three-dimension multiple composition reservoir simulators and fast decision-making techniques, PI and RS [41,42], were successfully developed and deployed to adapt the needs during that time. The decisionmaking techniques can be used to select well candidates and chemical agents, to optimize plugging agent volume and to forecast reservoir performance.…”