Innovative Method for Gas Lift Optimization on a Remote Satellite Offshore Platform: Reducing Environmental Footprint and Unblocking Hidden Optimization Opportunities
Authors: Challenger B. J. , Ismail A. A. , Shkorin D. D. , Rasool A. R. , Umar M. A. , Vincent J. N. J. , Alamsyah H. , Lin L. O. , Merang M. S. , Norden A. M. L. A. A. , Shahrom M. R. , Zin Z. M. , Kok J. , Sahat S. 
Published: September 2024

The paper addresses challenges associated with optimizing gas-lifted remote satellite platform that operates with limited facilities onboard, including constrained power supply, lifting capacity, and offshore logistics. The platforms, located in mature brownfield Offshore Borneo Island, encounter further obstacles stemming from the limited availability of instrumentation, coupled with lack of well test data. Predominantly, the platform employs dual string gas lift oil producers.

The method involves injecting nitrogen (N2) tracer upstream, allowing it to mix and dilute. The diluted tracer fraction is measured downstream to obtain the volumetric flow rate of gas lift injection and total produced gas using dilution equation. The innovative method, equipment, and software log injection and production data, adjusting simulation parameters based on return data to evaluate gas lift system integrity.

An adaptive modular solution was deployed to address the optimization challenges of a remote satellite platform operating under limited facilities. Battery-operated modular equipment, specifically designed for adaptability to the platform's constraints, not only navigated the operational limitations effectively but also ensured that production remained uninterrupted. Confronting the scarcity of surface and subsurface instrumentation in a mature brownfield, alongside the absence of comprehensive well test data, posed significant hurdles for gas lift optimization. An innovative methodology that precisely determines injected gas lift rates and accurately measures net gas production, particularly advantageous for dual string wells, offered a tailored solution that significantly enhanced well performance and decision-making despite the prevalent data limitations. The adaptive technologies, coupled with innovative methodology, enabled immediate optimization opportunity identification that may have otherwise gone unnoticed, contributing to the efficiency and productivity of the gas lifted wells. Furthermore, the reduction in required man-hours and elimination of generator emissions minimized personnel exposure to hazardous conditions, which collectively contributed to a notable decrease in the environmental footprint and enhanced the HSE risk profiles of the operations.

The data provided during the execution allowed the operator to calibrate the well models based on accurately measured parameters such as gas lift injection rate, net produced gas, real-time injected and produced gas composition, and injected gas lift split ratio. The actual measured parameters were used to determine the lifting depth and evaluate the annulus and tubing integrity. This case study showcases how the comprehensive data collected during the execution phase enabled to refine the well models by leveraging accurately measured parameters. These precise measurements were instrumental in determining the optimal lifting depth, conducting a thorough assessment of the annulus and tubing integrity, and making informed adjustments, thereby enhancing the overall efficiency and safety of the operations.