Water to Gas Production in the Barnett Shale Using FracBlock Gel Systems
A well in the Barnett Shale formation in north central Texas was producing only water and no gas. The well was drilled into the main pay section of the Barnett Shale and was completed in the 3,000-ft (914.4-m) horizontal portion. It consisted of several intervals that were perforated and hydraulically fractured. During the drilling of a 3,000-ft (914.4-m) lateral section, a weak spot was intersected. After the well was completed, it started producing 1,800 BWPD and no hydrocarbons.
The Barnett Shale is a sedimentary rock formation consisting of an organic-rich shale with components of sand and other sediments. Hydraulic fracturing and horizontal wells have made the Barnett Shale economical in the thicker sections, but in some cases, water production is so high it makes production uneconomical or shortens the life of the well and the ultimate recovery.
The Baker Hughes, a GE company (BHGE) FracBlock™ gel system was considered for this well for several reasons, including penetration, cost, and effectiveness. A gel system treatment was customized to penetrate deep into the fractures of the formation to reduce the flow paths from the water source into the fracture network around the well. Typical alternative treatment methods such as a cement squeeze can block the larger fractures but not the smaller features, which can be prolific and communicate out in the reservoir. For these reasons, a gel treatment with appropriate volume was chosen and designed to allow easier penetration of gel back into the fractures. No mechanical isolation was used on this well, but other wells with similar challenges have used isolation techniques.
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- No hydrocarbon production
- Excessive water production at uneconomic levels of 1,800 BWPD
- Horizontal section extended 3,000 ft (914.4 m)
- Attempted cement squeeze had failed
- Increased gas rate from 0 to 2 MMCFD
- Decreased production by 97%, from 1,800 to 60 BWPD
- Reduced operating cost by requiring no mechanical isolation
- Reduced health, safety, and environment risks by minimizing equipment needed for the operation
- Placed well back in production three days after treatment, minimizing downtime