An Integrated Scientific Workflow Enables Successful Perforating Operations in Offshore Southeast Asia
Authors: Satti Rajani , White Ryan , McClean Charlie , Ochsner Darren , Zuklic Stephen , Chong Jonathan , Bouziane Cherif , Oghittu Patrick , Fager Andrew 
Published: April 2018

Challenging reservoir environments often demand advanced perforating strategies in order to optimize perforation efficiency and maximize productivity. In this context, the use of advanced live well deployment systems has gained significant attention in recent years, whereby such systems are utilized to safely perforate and complete without killing the well, avoid the use of kill-weight fluids, optimize underbalance, reduce operational risks, etc. The operational success of these complex systems is driven by critical aspects like robustness and reliability of the system, integrated quality planning, and crew competency and training. Most importantly, a robust scientific testing & modeling workflow is required to insure that maximizing productivity as well as operational risk mitigation are balanced for the best possible outcome.

This study is focused on HP/HT wells in the Maharaja Lela Jamalulalam field, situated at approximately 50km offshore from Brunei coast and in approximately 65m of water depth. Due to inherent challenges (offshore, large intervals, high bottom hole pressure and temperature), the operator decided to execute a comprehensive scientific program (laboratory testing & numerical modeling) to design an optimized perforating strategy within a limited timeframe. As a first step, a series of in-situ experiments were conducted at the perforation flow laboratory to assess and understand the influence of shaped charges, gun size, underbalance mechanism, actual cement used, actual completion fluids and post-perforating hold times (suspension time) prior to clean-up for production. Complementary to the tests, CFD (Computational Fluid Dynamics) modeling was subsequently used to understand and investigate competing effects relating to core heterogeneity, debris/clean-up and productivity. In addition, pre-job dynamic event modeling was used to predict gun shock and mitigate operational risk, especially on the conveyance method used to deploy guns (coiled tubing in this case).

The data from the integrated experimental and modeling study provided insight into the characteristics of the perforations, influence of underbalance on debris and clean-up, transient downhole pressures, gun shock, loads acting on downhole tools, risk assessment and most importantly, the productivity. The measured and computed results from the scientific analysis were carefully analyzed and compared with operational aspects, concerns and limitations to finally deliver a solution that strikes a balance between operational risk vs expected productivity.

This unique scientific approach in conjunction with operational planning and execution ensured the flawless execution of perforating operations in complex offshore well completions in Southeast Asia. The significance of this integrated and systematic workflow is demonstrated by presenting details of the operational case-histories from these wells.