Well Clean-Up and Testing: Using Dynamic Simulations to Minimise Flaring Emissions and Optimise Well Testing

New production wells completed in the UK are subjected to increasingly stringent well clean-up and testing requirements by UK Regulatory Authorities. It is incumbent on UK operators to demonstrate as far as is reasonably practicable, that efforts have been made to minimize emissions during well testing operations to protect an operator's license to operate. In the past, this has involved committing to a permit with maximum flaring volumes and durations, but this case study demonstrates how dynamic modelling can be used to provide scientific evidence and credibility to well testing planning and operations to decarbonize and minimize environmental impact. Shell P&T has developed a methodology based on dynamic multiphase thermal-hydraulic simulations to model well operations including clean-up and testing. A multiphase dynamic model was developed to: (1) Perform a quantitative determination of the expected well clean-up rates versus process conditions of the well test equipment to maintain drawdown and liquid rates to facilitate efficient unloading of completion fluid and deliver a stable well test; (2) Minimize produced O&G volumes during kickoff, while completing commissioning and clean-up objectives of a complex Open Hole Gravel Pack completion; 3. Estimate the time dependent change in pressure in the well, during clean up (optimized on min. flared volumes); 4. Ascertain and optimise well kick-off using artificial lift, including N2 loading and the corresponding well performance assessment and range of expected well rates (it was not possible to start-up the brine filled well without lift gas), 5. Perform sensitivities on clean-up and well test for low productivity and IPR scenarios, and (6) Determine requirement to displace well to a lighter fluid to facilitate more stable kick-off.