Subsidence Remediation - Extending Well Life through the Use of Solid Expandable Casing Systems
Loss of wells and / or production due to significant casing damage caused by formation subsidence can be a costly problem, particularly in shallow high porosity reservoirs. Solid Expandable Tubular (SET) Cased-hole Liners (CHL) is one method being utilized to overcome damage to casing due to formation subsidence. The techniques developed for this remediation solution could also be used to repair casing in a number of other environments. Subsidence has been reported in many fields throughout the world including the Ekofisk field in the Norwegian sector of the North Sea, the northern Adriatic, the Groningen gas field in the Netherlands, Lake Maracaibo in Venezuela and in several fields in both Long Beach and Bakersfield, California.1 Subsidence can have dramatic consequences on production operations and eventually can completely shut down a producing well. Subsidence is expected within and above a producing formation where the reservoir rock is weak and porous (Fig. 1). As the fluids are extracted from the reservoir the rock is compacted, and in a shallow reservoir, this compaction can alter the overburden and may even be observed on the surface (Fig. 2). This paper discusses: · Techniques developed to remediate wellbores that have been damaged due to subsidence · Wellbore preparation · Installation procedure of a Solid Expandable Tubular Cased-hole Liner System · Challenges solved while attempting to expand the SET Cased-hole Liners downhole once the wellbore was prepared · Final solutions customized to remediate these subsidence challenges.