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.