Integrated Approach to Managing Formation Damage in Waterflooding

Abstract

Waterflooding is the most widely used secondary recovery concept in the oil industry. Once embarked on, it becomes vital to assure the proper planning and execution of a project. There are multiple examples of things that can go wrong if the project is not properly designed, and/or if the practices and standards are not adhered to. These include loss of injectivity, out-of-zone injection, early water breakthrough, loss of reservoir containment, significant CAPEX/OPEX overruns, injector-producer shortcircuiting, reservoir souring and scaling issues etc. Understanding of formation damage is one of the overarching themes in a waterflood project. It requires an integrated multi-disciplinary approach to conclude on an optimum design and strategy. Some of the issues that need to be addressed in the first place are: -matrix of fractured regime; -injectivity decline and necessary water quality specifications; -fracture growth over time and its impact on sweep; -risk of out-of-zone injection and loss of reservoir containment.Realising the magnitude of these questions, Shell has developed a suite of tools to tackle these issues and help in adequate designing and optimization of waterfloods. They include:ASCET (Actual and Simulated Coreflood Evaluation Tool). On-site coreflood tests at real-life conditions, measuring formation impairment as function of water quality. -FORDAM (FORmation DAMage) software. Estimation of injectivity decline when no ASCET tests are available. -PWRI-FRAC (Produced Water Re-Injection FRACture modelling). Quantification of fracture growth as a function of water quality and injection rate. -FRAC-IT (FRACture IT). Model the impact of fracture growth. Assess risk of out-of-zone injection and impact on sweep.Utilising these tools helps make informed waterflood decisions, improve water management, reduce (or eliminate) water disposal, lower environmental impact, avoid unnecessary CAPEX/OPEX.