Abstract

Casing integrity failure, whether through parted casing, leaky collars or some other issue, may result in less effective stimulation work due to abandonment of the plug and perf method and/or having to complete through a frac liner. In more extreme cases it could result in lost reserves below the casing failure point. Modern technology has provided a cost effective solution to this problem.

In this case, the operator confirmed parted 4-1/2 inch production casing at 9,761 feet (Fig. 1) in their northern Piceance Basin acreage. The operator would have to repair the parted casing in order to frac the lower six zones of the well. The plug & perf method for zonal isolation was required to effectively complete the 2,825 foot vertical pay interval. In order to complete the stimulation program, the goal was to repair the short section of damaged casing and restore pressure integrity to the well while maintaining a sufficient inner diameter (ID) to allow composite frac plugs to pass through the repair and set in the base casing's larger ID below the split. After a corrugated patch failed to provide casing integrity, the solution was a 3- 1/2 inch single-joint solid expandable system that was expanded downhole to cover and seal the parted 4-1/2 inch casing in conjunction with the use of custom made composite frac plugs.

The 30-ft., 3-1/2 inch solid expandable high-pressure, high-temperature (HPHT) liner system was deployed and expanded in a single trip. This system provided the required pressure integrity to withstand the frac pressures needed in this area. The 3.261 inch drift ID of the expanded solid liner allowed the operator to run custom 3.06 inch outer diameter (OD) composite frac plugs below the repaired section and successfully complete the well.

This installation was a success, as the operator had essentially written off 63% of the well's reserves due to the casing part occurring above a majority of the pay interval. The operator is now realizing full production from the entire well. Moreover, this single-joint solid expandable liner technology coupled with the special drillable composite frac plugs can be used in any HPHT formation to repair the common issue of damaged casing to allow plug and perf completions to continue.

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