With the current low oil prices, Operators are under increasing financial pressure to look at new ways to safely maximize the value of their assets whilst operating within the constraints of the regulatory guidelines. Many operators have placed a greater emphasis on restoring existing wellbore integrity to develop their assets more efficiently instead of performing an expensive side-track or drilling costly new replacement wells.

This paper will review the challenges faced by a major American Operator while drilling an unconventional well in the Marcellus Shale Basin where casing integrity issues arose.

Solid expandable tubular technology has provided operators with a cost effective solution to remediate wellbores for a number of years. Since 2009 the High Performance (HP) solid expandable patch has been installed in over 170 wells, addressing completion / production issues, however, these systems had always been run on jointed pipe.

The recent (2015) deployment of an HP expandable patch on coiled tubing for the operator provided a technical and more economically attractive solution over alternative options. The planning, procedures and execution of this first ground breaking installation will be discussed in this paper.

The operator required a solution to seal off squeeze perforations which would have to withstand high pressure fracturing operations. The area regulatory agency had suspended their operations, not allowing completion of the well due to a poor cement bond behind the production casing. This required remediation using a perforation and squeeze operation. The cement squeeze alone would not hold up to the high pressures required to fracture the well. An HP patch provided the optimum solution that would meet the requirements to complete the well. Side-tracking or drilling a costly replacement well, did not provide an economic option.

A coiled tubing unit was used to perform the required cement squeeze. Since the HP patch could be run on coiled-tubing, it eliminated the need to mobilize additional equipment saving the operator time and money. After squeezing cement, the 4-1/4in HP patch was successfully installed into the 5-1/2in casing covering the squeeze perforations and then tested to 9,900 psi, - more than enough to withstand the planned fracturing pressures.

Careful planning and operational support gave the client the confidence to install the expandable HP patch on coiled tubing to fully restore their well integrity. Over the last few years the HP patch has been developed to be deployed by various methods, thus providing significant opportunity for operators to revitalize their wellbore with a more effective and economical outcome.

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