A Middle East operator employed Production ExPRESS™ rapid production response solutions to reduce environmental impact during underbalanced CT drilling operations, yielding record productivity while eliminating approximately 28,800 metric tons of CO2e from flaring avoidance alone.
A Middle East operator needed to combat reservoir depletion in its tight gas carbonate fields. To maximize production from the reservoir’s potential sweet spots, the operator planned to drill a triple‑lateral well. However, the well’s high hydrogen sulfide (H2S) concentrations—up to 6% in some areas—posed significant HSE challenges, requiring additional planning and safeguards.
Instead of a conventional overbalanced drilling approach, SLB proposed underbalanced drilling (UBD) through coiled tubing—with a closed‑loop flowback system to minimize environmental impact and protect personnel from hazardous gasses. Not only would this technique decarbonize operations through flaring avoidance, it would speed drilling time while reducing the risk of formation damage, fluid losses, differential sticking, and other drilling challenges.
SLB deployed Production ExPRESS rapid production response solutions to support the campaign’s simultaneous production and UBD needs. The end‑to‑end surface package consisted of a remotely controlled drilling choke, a comprehensive solids management system with real‑time solids monitoring, and effluent handling equipment. SLB adapted all flowback equipment for maximum compatibility with the operator’s existing surface well testing equipment.
SLB rigged up its plug and trash catcher and dual-pot cyclonic desander to remove large pieces of debris and separate solids from the well effluent. Real-time solids monitoring and measurements enabled the drilling team to adopt different drilling scenarios based on the actual solids production rate. Additionally, SLB removed H2S by pumping H2S scavenger at strategically selected points and connecting all vent lines to H2S scrubbers. An SLB separator efficiently separated the produced well fluid while providing accurate flow rates.
Using Production ExPRESS solutions, the operator successfully completed the world’s first UBD program using fully recycled liquid and a closed‑loop flowback system for gas and solids within a high‑H2S environment. In total, the customized surface equipment handled 44 metric tons of solids and treated 134,000 bbl of water with no issues. Throughout UBD operations, the operator exported approximately 360 MMcf of gas and up to 4,800 bbl of condensate to its production facility—avoiding approximately 28,800 metric tons of CO2e emissions that would have resulted from flaring.
What’s more, the implementation of underbalanced CT drilling delivered record productivity—nearly tripling the gas production of the previous-best, triple‑lateral well drilled using conventional overbalanced drilling techniques.
