Subsea-processing technology (SPT) is one of the frontier tools currently been explored by the oil and gas industry to open new opportunities and achieve more-effective exploitation of offshore oil and gas reserves. Exploration and production has moved into unlocking reserves that are less attractive and in difficult environments (e.g., marginal deepwater fields). These marginal fields are located remotely offshore and require one form of processing or another before they can be productive commercially. This paper focuses on the applicability of SPT employing multiphase pumps (MPPs) to develop marginal fields commercially. This was as a result of the technology selection established by a comparison of performances of several SPTs for effective development of marginal fields using tools [e.g., quality function deployment (QFD)], and evaluated further using an analytical hierarchical process (AHP), resulting in the most effective innovative SPT for marginal-field development. The result from these tools was validated further in their applications to real-life fields, and this is achieved by specific field-case simulation studies using the OLGA transient multiphase flow dynamic model program to commercially develop marginal fields.

Objective/Scope: International and National oil companies have in their portfolios deep offshore marginal fields. Development of these fields is usually constrained by the CAPEX, OPEX, flow assurance and safety issues, which increases with maturity of the field. Subsea processing technology (SPT) is not only pivotal for unlocking such fields, but offers a novel approach that meets the challenges of developing offshore marginal fields. The present paper explores conceptual development from some of the most innovative solutions and performance analysis of the optimal SPT with field case studies demonstrated. Methods, Procedures, Process:The paper provides a reassessment of the different SPTs available in the market as well as the limitations of such technologies. Conceptual development is carried out using a 3-step approach involving the Quality function deployment (QFD) and its tools, the Voice of customer (VOC) and Quality Matrix or House of Quality (HOQ) that analyzes and compares the capabilities of various SPTs to overcome the techno-economic challenges of marginal fields. Revalidation of results from the QFD process is done using Analytical Hierarchal process (AHP) and its pair wise comparison process, leading to the optimal innovative SPT for marginal field development. Field case analysis of this novel solution is applied to fields in the North Sea and Gulf of Guinea over an eight years period. Results, Observations, and Conclusions:The present paper validates the effectiveness of SPT in tackling marginal field techno-economic challenges such as large CAPEX and OPEX, slugging, low recovery rate, remoteness of location amongst others issues. Its application in one of the fields led to increased projected revenue of up to $450,000,000 in recovery, as well as significant reduction in maintenance and work over costs. The analysis shows that SPT such as the deployment of Multiphase Pumps can be a game changer if effectively applied in marginal field development.Novel/Additive Information: The paper explores the novel application of QFD and AHP to develop offshore marginal fields. These tools have been used effectively in so many fortune 500 companies, where they have led to a significant reduction in cost as well as reduction in project implementation time. Proper application of the processes described in the present paper can serve as a better alternative over the traditional field conceptual development, to maximize recovery in offshore marginal fields.