Schlumberger

Case Study: FLOTHRU System Saves 3 Days and Reduces Fluid Costs 18% in Operator’s First Horizontal Dry Gas Well

Integrated drilling program optimizes hole cleaning, ECD management, and ROP

Challenge: Enhance hole cleaning, manage equivalent circulating density (ECD), and maximize ROP in a dry gas well.

Solution: Incorporate the FLOTHRU organophilic water-base reservoir drill-in fluid system as part of an optimized drilling program.

Result: Drilled the well to TD 3 days ahead of plan and reduced drilling fluid costs by 18%.

Drill and complete a dry gas producer

An operator in Romania needed to drill and complete a dry gas producer, which would be the company’s first horizontal well. Several challenges—including a depleted production zone, fluid invasion, and clay hydration—were identified during the planning stages of the drilling program and required attention. The depleted production zone exhibited low pore pressure and required a fluid density range of 1.10–1.15 relative density. In addition, the operator wished to avoid NPT and issues related to service quality and HSE.

Employ an integrated drilling solution

M-I SWACO recommended a combination of the FLOTHRU system, wellbore cleanout tools, and expert engineering to overcome the challenges of drilling and completing the well. The FLOTHRU organophilic water-base reservoir drill-in fluid system is designed to eliminate the need for chemical cleanup treatment, which involves aggressive and potentially damaging chemicals. A team of M-I SWACO engineers formulated the FLOTHRU system to meet the density specification. For enhanced flowback, the team included hydrophilic starch and carbonate components in the program to create channels in the filtercake for preferential flow of hydrocarbons.

Engineers also used OPTIBRIDGE bridging agent selection software to determine the correct bridging particle sizes. For optimizing and monitoring hydraulics and wellbore displacement, the team used VIRTUAL HYDRAULICS drilling fluid simulation software and the VIRTUAL CF displacement simulation software module.

Controlled drilling helped maintain ROP and ensured that the hydraulics properly cleaned the wellbore. The MONGOOSE PRO dynamic dual-motion shale shaker effectively managed drill solids and minimized dilution. Wellbore cleanout tools utilized included the RAZOR BACK casing cleaning tool, BRISTLE BACK casing brush, MAGNOSWEEP II wellbore cleanup magnet, single-action bypass sub jetting tool, and WELL PATROLLER validation tool. These cleanout tools remove downhole debris and validate the success of the cleanout.

Saved 3 days and reduced drilling fluid costs by 18%

The casing was scraped and the blowout preventer jetted before displacing the open hole with the solids-free FLOTHRU system and the casing with potassium chloride completion brine. The expandable sand screen was run to TD and actuated without issues. The well was brought online with minimal drawdown.

The well was drilled to TD at 5,036 ft [1,535 m]—deeper than the projected TD by approximately 65.5 ft [20 m]—without any NPT or issues related to hole, mud, or service quality. Despite exceeding the TD, the overall mud costs for the entire well was 18% below the planned AFE. The optimized drilling solution saved the customer 3 rig days.


Download: Case Study: FLOTHRU System Saves 3 Days and Reduces Fluid Costs 18% in Operator’s First Horizontal Dry Gas Well (0.35 MB PDF)

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