During subsurface activities such as cleanout of appraisal and development wells after fracturing, testing of appraisal and development wells, and well kickoff/circulation during intervention, considerable volumes of gas are flared every year. Gas flaring is one of the more challenging energy and environmental problems facing the world. This has incurred a revenue waste and continues to have an effect on the environment because of hydrocarbon emissions. Moreover, flaring causes direct release of unburnt condensate, toxic fumes, noise, and heat that can jeopardize the safety of personnel working in rigless operations. In addition, it leads to the release of carbon dioxide and carbon monoxide, which is one of the main causes of global warming.
Petroleum Development of Oman kicked off the Subsurface Flare Reduction Project in 2021 to ensure continuity in growing the business and generating revenue while reducing the carbon footprint of operations. The two main value drivers of the project were to minimize health, safety, and environmental effects and reduce greenhouse-gas emissions in line with the company’s goal of moving toward net zero by 2050 and to maximize hydrocarbon recovery.
The journey to reduce subsurface flaring started by looking into day-to-day operation and identifying key contributors. Post-fracturing cleanout has the biggest share of flaring (59%), followed by flowback loop (20%), then well testing (13%), and halite cleanout (7%).
Once key flare contributors were mapped out, the company began to work collaboratively and in an integrated manner with all the different stakeholders involved to come up with short- to mid-term solutions and, in parallel, scout for new technologies that would yield a more sustainable result. As a result, the company created a funnel of opportunities and constructed a 5-year road map to reach the end goal. This paper highlights some of these improvements that have matured and others that are currently progressing.
In the first year, 2021, the company managed to reduce subsurface flaring by 37%. This reduction was accomplished by introducing two efficiency improvements that included a successful flareless halite cleanout trail with a full-scale implementation plan and the use of test separators in line with sand-management system units to verify the flared figures. This resulted in a 50% correction factor to the data on hand. Going forward, the focus will be on maturing the new technologies that will further reduce subsurface flaring such as green completion, wellhead compression units, and mobile flare gas recovery. Given the complex nature of this project and the multidisciplinary efforts from petroleum engineers, operations, engineering, well services, and new technology, constructing a successful working plan to address this issue required effective collaboration and thinking outside of the box to find innovative solutions. As a result, a funnel of efficiency opportunities was constructed with a clear timeline including green completion, wellhead compression, prefracture hookup, and mobile flare gas recovery units.