Published on 16 July 2018
Casing patch restores well integrity needed to resume fracturing, Canada
Repair fracture port with restricted ID
An operator in Cochrane, Alberta, Canada had to restore the integrity of a well to start fracturing it. A fracture port at stage 30 of 36 stages opened prematurely, necessitating a patch. However, the task was difficult due to the contrast between the lighter-weight casing in the zone to be sealed and the heavier-weight pipe uphole. The largest ball that had to pass through the patch had a diameter of 3025in [82.55 mm], and the operator could only mill out the fracture ports to a maximum of 4.56in [115.82 mm] to reach port 30.
Ensuring a Secure Seal with a Moldable Patch
To fix the leaking fracture port, Saltel Industries installed a 5.5-inch [139.7 mm] reinforced patch after the well was killed using 7% KCI water. They positioned the top of the patch within the 4.89-inch [124.21 mm] nominal ID casing, expanded it over the restricted 4.56-inch [115.82 mm] ID fracture port, and then pushed it back into the nominal casing ID. A drift ring confirmed a final ID of 4.193in [106.502 mm], making it possible to restart the fracturing operation with the largest ball passing through the patch.
Successful Fracturing with No Leaks
Fracturing the Well with Precision
The operator carried out all 29 stages of the well’s fracturing process with precision, using a pressure of 8,400 psi [58 MPa] and a pump rate of 44 bbl/min [7.04 m³/min]. The operator made sure to closely monitor the pressure and pump rate throughout the entire process, ensuring that the well was fractured to the desired specifications. The high pressure and consistent pump rate allowed the operator to achieve the desired results, further improving the well’s potential for production.
Use a Saltel expandable steel patch to accommodate the differing ID requirements of the fracture port and the nominal casing. The patch held strong throughout all 29 stages without any leaks. This repair was a significant triumph for the operator as the well became one of its highest-volume producers in the Cochrane area.