Successful casing reinforcement campaign with Saltel patch
Successful casing reinforcement campaign with Saltel patch allowing hydraulic fracturing operations
North Dakota - Prior to starting hydraulic fracturing operations, the casing inspection outlined 7 weak spots in 5 different wells, due to drilling operations. Despite no leak was detected, logs indicated the casing thickness did not allow using frac treatments as per initial plan. The client had the choice between using a fracturing string or setting a casing patch to increase the internal pressure rating of the damaged casings.
The client preference was to restore the full casing integrity. This would allow keeping maximum internal diameter (ID) to implement the fracturing program, without increasing the friction losses with a tie-back system. The casing patch operation still needed though to be competitive.
Saltel Patch (7in Ultraslim) was selected for its better set ID (5.69in). It was determined that the mechanical reinforcement of the patch inside a 7in - 32 lbs/ft casing was over 2,500psi; pressure above which stress is transmitted on the back side of the patch, to the casing.
A patch setting campaign was awarded after the success of the solution field tested in a well.
Five patches (Length 4m -13ft) were selected to cover the 1ft weak sections and one patch (11m - 36ft), to cover two weak spots in the same run.
The patches had to be set back to back to increase the efficiency of the operations, and keep the costs down.
The 7 patches were successfully installed (one day/patch operation). The wells were pressure tested to 9,500psi.The client was able to successfully fracture the wells without casing failure.
Saltel Expandable Steel Patch features:
■ Patch through Patch
3 Expandable Steel Patches set in the same well to shut off perforations, leaving large ID and strong collapse pressure ratings