Reviving a Complicated Idle Well: A Multi-Intervention Example from the Sultanate of Oman

Abstract

A well targeting deep a gas formation in the central part of the Sultanate of Oman was drilled in February 2010. At a later stage a fracturing operation was conducted but an integrity issue. This integrity issue consisted of a communication between tubing and casing annulus which led to the well having been isolated with cement plugs. This paper describes a successful work cycle of restoring well accessibility and reviving production from an idle complex well using different means of well intervention. A Hydraulic Workover Unit attended the well to fix the integrity issue of the casing/ tubing annulus communication. An old casing was recovered and a new one installed. Next a coiled tubing unit attended the well; it encountered complicated well conditions characterized by the presence of metal junk left behind after a previous milling operation. In addition there were 3 cement plugs and 700 m of proppant which needed to be removed in order to establish access to the producing formation. We adopted an ""agile" approach and deployed a "super magnet" by slickline. Following the removal of the cement plugs we cleaned the well from proppant using coiled tubing with sand return management at surface. The well which was originally planned to be abandoned due to the complexity of its integrity issues was successfully recovered. The integrity issue was fixed by installation of a new external casing patch using a hydraulic workover unit. The approach of using a combination of different well intervention methods enabled reviving the idle well and unlocking access to hydrocarbon reserves. Full passage to the target depth was confirmed which made the operation a full success. Challenges such as the presence of metal junk, logistics constraints to supply a large volume of water for long-interval milling and cleanout operations, management of abrasive sandy returns at surface were overcome through a collaborative approach between all parties involved. This paper presents a case where we successfully brough back on production a well which had been shut in due to complex well integrity issues. We present the lessons learnt as many of these can be applied to other challenging projects. This show case reveals how the combination of different types of well intervention techniques can help restore production from a well with complex well integrity issues.