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.

Waterflooding concept and corresponding water quality 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.

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