Development of existing mature fields can pose a wide variety of specific challenges originiating from earlier programs and extended production operations. Wellbore stability parameters can change as fields mature and wells age requiring suitable combinations of innovative techniques and new technologies to further develop these fields. Added challenges arise when the development program is based on re-entering existing wells.

Al-Khafji Joint Operations (KJO) is developing and producing the offshore Al-Khafji field, located in the former offshore neutral zone between Saudi Arabia and Kuwait. The field has commenced oil production in 1961.

To sustain and meet the increased production targets, the operator started implementing a novel drilling and workover project. The program was designed to mitigate expected challenging borehole instability problems in the Wara and Burgan shale formations, resulting in issues such as stuck bottom-hole assemblies, poor hole enlargement and cleaning, and poor deviation control. The instabilities are encountered in the build sections of the horizontal wells and are further complicated in re-entry wells, due to the limitation is casing string sizes from surface. The novel program implemented incorporated an optimized drilling fluid system and a solid expandable open-hole liner that was utilized to case off these unstable formations and allow the well to be drilled without downsizing the planned production zone size and compromising well objectives.

This paper details the extensive studies and planning, originating from lessons learned that were implemented in the integrated program with focus on the innovative techniques and new technologies used in this field. Specific focus is placed on the solid expandable system used as it formed an integral part of allowing a successful implementation of these programs.

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