Redefinition of Well Interventions in Naturally-Fractured Carbonate Reservoirs through Real-Time Coiled Tubing-Deployed, Fiber Optic Monitoring

Abstract

Abstract The South Region of PEMEX in Mexico produces 530,000 bopd from mostly mature, naturally-fractured carbonate reservoirs. The majority of the well interventions in the area present complications, due to a combination of extreme operational conditions, variety of reservoir rocks and fluid environments, and complex well configurations required to produce from large intervals in different flow units, many supported by active aquifers and secondary gas caps, that eventually reduce the production of oil as the water production and gas production increase. Rigless stimulation and maintenance well operations have been recognized for decades as efficient and cost-effective production enhancement enablers in the area. As the fields mature and the well interventions become more challenging, there is a higher demand on the operator side to successfully pinpoint the intervals and execute treatments that overcome unknown downhole parameters with confidence, maximizing success and avoiding additional remedial work. A new approach, incorporating real-time, coiled tubing-deployed, fiber optics monitoring, was implemented in three well interventions in southern Mexico. These included: (a) the isolation of a high-water producing interval in a low-pressure reservoir using an inflatable packer; (b) a matrix stimulation requiring the accurate placement of fluids and diversion stages; and (c) the perforation and testing of several intervals in a gas injector well. Real-time down-hole measurements of performance have been found to be an excellent option to improve the success rate in the well interventions in southern Mexico, allowing capturing unique quantitative feedback from the well, to be able to act with a greater degree of precision to increase production. Coiled tubing-deployed fiber optics proved to help the operator to improve efficiency and to optimize intervention performance with confidence in real time.