Aligns with United Nations Sustainable Development Goal 13
Reduced 240,000 metric tons of CO2e by eliminating flaring over two years
An operator in western Kazakhstan operates a giant onshore carbonate gas field located in a remote environment with an extreme winter climate. The extracted hydrocarbons contain up to 4.5% toxic and corrosive hydrogen sulfide (H2S), as well as carbon dioxide (CO2) which can be highly corrosive in certain conditions.
To maximize production, the operator was drilling horizontal wells and applying acid stimulation to a relatively thin oil zone. However, its processing plant facilities were not designed to handle the large volume of water returning to the surface as part of the acid stimulation flowback. The returned fluids needed cleanup to achieve plant water cut acceptance of 1%; without it, hydrocarbons could not be diverted to the plant after stimulation.
As part of the global movement to reduce carbon emissions, the operator was committed to minimizing its environmental impact while increasing production capacity. An additional goal was to achieve true zero-flaring well cleanup and testing activities at the field.
The possibility of using gas compressors to enhance gas flow in the production pipeline was considered but ultimately dismissed. This decision was based on the challenging nature of the cleanup process, which involved unstable slugging flow, as well as the sensitivity of gas compressors to different types of fluids. Adapting gas compressors was considered too complex, energy-intensive, costly, and impractical for a mobile, rapid-response solution.
Through their longstanding partnership, the operator and SLB collaborated extensively to develop the most efficient solution. To address the challenges of cleanup operations, they used Production Express solutions, which are specifically designed to facilitate well cleanup and testing while eliminating the need for flaring. This zero-flaring solution is part of the SLB Transition Technologies portfolio, which focuses on assisting operators in reducing their emissions by customizing integrated techniques to meet each operator's specific needs.
The zero-flaring solution was designed to separate the hydrocarbons, water, and acid, then inject hydrocarbons into the production pipeline. But first, it had to overcome pipeline backpressure issues. Use of a high-pressure separator helped remove hydrocarbons from the water and contaminated sludge. Then, the surface pressure was boosted using the Reda Multiphase HPS™ horizontal multistage surface pump to overcome backpressure issues so the fluids could enter the production line smoothly. The setup was also equipped with a Vx Spectra™ surface multiphase flowmeter to measure and account for the recovered fluid before sending it to the production pipeline.
SLB well cleanup advisor software was used to simulate the flowback, including pressures and flow rates at the surface during cleanup operations. Based on these simulations, the surface equipment was adapted to best handle the expected flow rates. As part of the package, optimum operational guidelines were developed for the zero-flaring operation under various scenarios. This was the best solution that did not require flaring, even when wellhead pressures were lower than the production flowline pressure.
During the entire cleanup operation, a total of nine wells were processed with 1.4 Bcf of gas and 440,000 bbl of oil saved from flaring. Over a two-year period, the solution reduced the carbon footprint by 240,000 metric tons of CO2e. The use of a multiphase pump together with customized surface well testing equipment provided an essential and long-awaited solution to the zero-flaring goals. The cleanup package was able to safely handle high H2S and acidic fluids in a high-pressure environment while complying with HSE and government standards.
Zero flaring in the field is a successful innovation now being used to bring other new wells to production. The zero-flaring package also proved to be an effective pressure-boosting package, which the operator is using to improve production revenue in cases where low wellhead pressure must overcome backpressure from production pipelines. Close collaboration between the partners ensured an effective solution that would achieve the desired production results while also protecting the environment.
