An Insight into the Optimal Development of a Marginal Field – Pressure Complexity and Multiple Hydrocarbon Targets

Abstract

Maximizing the end-life development of a marginal field with small pockets of undeveloped hydrocarbon could pose an unattractive venture, especially considering the attached economic value. The Well design and delivery approaches presented in this paper illustrate how available subsurface engineering tools and knowledge were deployed in the planning and execution phases of the Umuseti-7 development well. This well is an Oil and Gas "fault-scooping" producer tasked to bring the Umuseti main structure (OML 56) to complete life-cycle development by providing structurally high drainage points in its remaining viable reservoir accumulations and a dependable conduit for the realization of overarching field development ambitions. This paper showcases the development strategy undertaken, challenges encountered, solutions employed, and lessons learned during the preparation and implementation stages of the Well delivery cycle. It demonstrates the simple well plan employed despite grueling subsurface complexities and the measured approach applied in drilling and completion program phases. Apt Well construction and depletion plans were developed, reliable materials, equipment, and tools deployed, and thorough "Industry Best Practice" processes followed (including Simultaneous Operations-SIMOPs) from project commencement to conclusion. Results of the Umuseti-7 well show single-well near-term oil gains of about 2000 bopd (this represents a 70% increase in asset-controlled oil production capacity) and medium to long-term NAG gains of 5-15 MMscf/d. This Well project ultimately purposes to sustain this marginal asset’s (Umuseti/Igbuku field) oil production capability and propel its gas monetization drive.