A New Tool to Evaluate Water Injection Performance in Waterflooded Reservoirs– A Technology Innovation

Abstract

Abstract Waterflooding through water Injection is one of the most effective secondary method to improve oil recovery. Integrated water injection management comprises managing the performance at the reservoir, the wells and the surface and their interdependencies. Lack of effective management of any of these would pose serious concern on incremental recovery due to water injection. Although, water injection (WI) has been in place for many decades, a comprehensive technique to measure the integrated performance of the water injection due to better subsurface management, and/or well management, and/or surface WIM management is not well-established in the industry. Thus it is very difficult to evaluate and compare overall performance of a WI project with the efficiency of other WI projects. In the current times of limited CAPEX spending, thus a technique is required to evaluate various WI projects under the same yardstick, so as to decide on which project more money need to be spent for better returns. Such yardstick which evaluates each of the WI modules (WIM) of subsurface, wells, facilities WIM helps thus then to consider optimal remedial measures to attain excellence. This paper explains how an easy, doable and effective method to evaluate WI performance was generated with help of Key Performance Indicators of the subsurface, wells and surface facilities for a WI project. This paper reviews the processes which affects the WI performance and identifies Key performance areas (KPA) of influence during Water injection stage. On the basis of merit and impact of each KPA on the overall effectiveness of WI, performance Indexing has been attempted to generate Key Performance Indicators (KPI) in an innovative manner. All KPIs are integrated together with respective weightage factor derived from their individual influence on WI performance into an overall performance indicator. An integrated surface-to-wells-to-subsurface system optimization has been the key consideration during the development of this technique. A worksheet with inbuilt formulae leading to the estimation of all Key Performance Indicators and Overall indicator has been constructed to be used for any WI projects with option of related data inputs. It has been tested on real data of few offshore fields of PETRONAS as sample test and proved to be a valid indicator of WI performance. To test the robustness of the tool it was blind tested by taking out the data of some key injectors in one of the better water flooded reservoirs. This tool has thus proved effective to gauge the performance of a WI project, remains a measure to compare and rank performance with respect to other WI projects. A continuous plot of the KPIs helps to identify the concerned areas for possible improvement. This technique is thus capable of diagnosing all sub-optimal areas within a WI project simultaneously, which when addressed leads to operational excellence and improvement in oil recovery. Recent usage of this tool to rank WI performance of different projects helped to initiate competition between different operators for improvement.