Subsurface & Surface Optimization Helps to Extend the Field Life with Significant Contribution to Production Sustainability from Mature Gas Field through Integrated Asset Modeling
Authors: Zafar Jahangeer , H. Shah S. Shabbir , Sabir Umais , Arsalan Hafiz , Awase Azar 
Published: February 2025

Production sustainability and optimization from mature gas field that was near to abandonment pressures were very challenging while maintaining the operating cost. This paper discussed case study of an Integrated Asset modeling for brown field that was producing at sharp decline rate with depleted pressures and high WGR, complex reservoir dynamics, along with complex surface network. The scenario demands novel approach with cost effective solutions to sustain and optimize production to make field more economical.

R-Field was discovered in 2014 with complex reservoir heterogeneity behavior. Field was put on production in 2015 and achieved peaked production of 200 MMscf/d. Reservoir pressure dropped to 300-700 psi with significantly increased in WGR and it will be more strenuous with wells completed with larger tubing. Integrated modeling approach was adopted to conduct complete system-analysis with multiple sensitivities were performed to simulate application of string upgrade, low pressure/booster compression, de-liquification techniques along with multiple flow diversion that assist in identifying sustainability and removing potential bottlenecks. Subsequently, optimum strategy was adopted and implemented in segments to sustain and optimize production.

This study employs integrated network modeling to address the challenge of meeting production mandates amid ongoing field decline. A comprehensive full-field network model, iteratively refined with sensitivity analyses, serves as the foundation. Various hypothetical scenarios were examined, forming the basis of an engineering strategy harmonizing reservoir, well, and facility guidelines to reveal the system's latent potential. Optimized simulations forecast a substantial increase of about 43 Bscf in gas recoveries, extending the field's operational life by seven years. The strategy aims to elevate production and reserves while enhancing field profitability and optimize operating costs. Project execution initiated in February 2021, the project included optimized compression schemes, tubing sizes, velocity strings, and deployment of cost-effective de-liquification's technique. The study outlines challenges and offers recommendations for production efficiency enhancement and standardized well potential determination.

The application of a standardized Integrated Asset Management (IAM) solution not only aids in precise capacity estimations but also minimizes potential production deferment, optimizing system cost-efficiency. This work forms a crucial foundation for a sustainable long-term field development plan, ensuring energy resource sustainability.

The initiatives and successful outcomes of the case study significantly contributed to optimizing production from mature gas field through integrated network modeling, that enabling to maintain optimum production levels. At present, the field is producing at ~8% incremental volume over and above of initial base volume and future plans have also been formulated to sustain the production as per simulations that will further add ~6% incremental volume.