Green Field Precommissioning Challenges & CAPEX Optimization in View of Global Hostile Oil Economic Environment - Case Study from Middle East Field
Authors: Rachapudi Ramarao , Al-Nuimi Saber Mubarak , Subaihi Maad Hasan , Emegano Theodore , Elbekshi Amer , Aydinoglu Gokhan , Alyammahi Moza , Gutierrez Daniel , Mohamed Abdelrehim Samy 
Published: November 2019

New green field development projects require pre-commissioning of oil producers and injectors to establish the potential of the wells in order to ensure the mandated production and injection targets before handing over the wells for tie-in activities as part of commissioning operations. In addition pre-commissioning activities are required for data gathering to confirm the reservoir properties and further to optimize the long term development strategy. However, the challenge is to deliver the wells to EPC contractor before the mandated timeline with the given constraints of limited resources, simultaneous operations (SIMOPS), remote location and sour fluid environment. Therefore, the objective is to optimize the pre-commissioning duration without compromising the reservoir data gathering requirements along with minimizing the capex with an aim of maximizing the project NPV.

This paper describes about a case study of systematic optimization process being adopted in one of the newly commissioned green fields to minimize the duration of wells pre-commissioning to be able to meet the project milestone. During planning stage minimized the overall duration considering interfaces required among the activities including PAD drilling, EPC tie-in, rigless unit plan and SIMOPS requirements. Further data gathering planned as part of pre-commissioning activities were customized considering the availability of appraisal wells data. The important optimization process was implemented during actual execution stage to reduce the duration and cost by creating task force team to make real-time decisions. Customized approaches were implemented including rigless unit lay out optimization, utilization of temporary flow lines to reinject the produced oil to the existing appraisal wells and operating ESP’s instead of nitrogen kick off to minimize the resources and duration. Trucking option was not selected due to HSE concerns and remote location. Overall this optimization process implemented within the limits of reservoir guidelines, HSE requirements & environmental limitations.

In general each well takes around 1.5 months to complete the pre-commissioning activities based on remote location and sour fluid environment. Successful completion of pre-commissioning activities, ensured meeting the business plan mandated profiles and optimized the surveillance plan. Overall, this optimization process ensured delivery of 45 wells required as part of first oil, within mandated time line of one and half year. Capex corresponding to rigless jobs was reduced by 50% and pre-commissioning activities were completed adhering to 100 % HSE requirements and minimized the gas flaring requirements. This optimization process will be further used in coming years for the next phase of planned development in the same field.

Optimization process described in this paper will add value in reducing the capex and pre-commissioning duration of marginal fields, producing sour fluid at remote location and require simultaneous operations due to PAD drilling.