Successful Installation of the First Deep Water Single Trip Stand-Alone-Screens Completion in the Industry Saves rig Time
Authors: Ojeh-Oziegbe Osehojie , Apremu Aye Yeneapre , Murdoch Euan , Walker John 
Published: July 2019

Abstract
Every field development faces the challenge of keeping capital and operational expenditures (CAPEX and OPEX) within reasonable limits, while at the same time exploring matured or new technology that can achieve cost limit objectives.
With the uncertainties, cyclic nature, instability in the oil and gas global investment markets, and the fluctuation in crude oil pricing, operators in energy exploration and production (E&P) industries as well as service providers are constantly looking for better and more efficient cost-saving products and services. The challenge of maximizing hydrocarbon recovery in deepwater completions with minimum investment, while maintaining the highest level of health, safety, and environment (HSE) and service quality is a continual catalyst for new products and service delivery techniques.
In the operator’s Bonga subsea field, the conventional completions techniques for all open hole standalone screen (SAS) completion installations are performed in multiple trips. The first trip involves running the lower completion including a gravel pack packer with screen assembly which allows a gravel pack packer service tool and an internal string with a pump-thru wash-down capability to enable toe-heel circulation, packer setting, and testing. The internal string, which is comprised of the packer setting tool, internal wash pipe, and accessories, is recovered after completion of the first trip into the open hole reservoir section. The second trip involves running the production tubing, production packer, downhole gauge mandrel, safety valve, and other completions accessories and landing the production string into the lower completion and on the tubing hanger.
The major objectives and drivers for the innovative open hole single trip stand-alone screen completion (STC-SAS) in a deep offshore environment is basically to save rig costs, use proven and emerging technologies, employ completions best practices, reduce exposure of personnel to safety hazards, and reduce non-productive times (NPT). New completions techniques with different services and product providers could pose a challenge in terms of vendor interface management, equipment compatibility, and procedural integration of multiple downhole tools with different operating boundaries and limits.
The STC-SAS completions concept in deep water was generated with the operator’s Wells Front End Completion and Well Intervention team in December 2015. This was driven by an opportunity to further reduce well delivery rig time which is at a premium in deepwater subsea completions. The average completions time in the field stood at 10 days per 10,000 ft well. The group was challenged to further improve the well delivery time. However, there was no benchmark as the industry data showed that a single trip open hole stand-alone screen completion had not been installed globally in a deep water subsea environment.
This paper presents the evolution of the completions design, the critical challenges in the service companies management, downhole equipment interfaces, operational steps, risks, and the lessons learned during the job execution that led to the successful installation of the industry’s first single trip open hole sandface STC-SAS in a deep water environment.