Downhole Isolation Valve Performance in Drilling and Subsequent Completion Operations

Downhole Isolation Valve (DIV) technology has been used for numerous reasons to improve the efficiency of drilling and<br>completion operations all over the world. The technology, which basically involves the installation of a valve system for<br>isolation within the casing string above the reservoir to be drilled, was used in East Java, Indonesia to assist in the drilling<br>and completion phases of the development of a sour gas reservoir that is very prone to severe circulation losses. The fractured<br>and/or vugular nature of the geological formation involved, the Kujung formation, is frequently if not consistently<br>responsible for kick – loss cycles and well control incidents. In fact, well control incidents were experienced on two previous<br>wells drilled using conventional methods in the area and large amounts of cement and lost circulation materials were used to<br>mitigate severe and total circulation losses, which consequently reduced the productivity of the wells. The main reason for<br>the utilization of a DIV was to isolate and prevent sour formation gas from reaching the surface, should severe circulation<br>losses and subsequent well kicks occur. The DIV was also meant to produce improvements in reservoir productivity as well<br>as in drilling and completion efficiency, as roughly measured through the time required for tripping and for dealing with well<br>control incidents.