Design Optimization for Drilling Development Wells

Abstract

The successful drilling campaign from all aspects is all depending on a robust solution developed during the design phase on the well construction process. This paper describes the advance technical engagement between the operator and integrated drilling services provider to generate an optimum well design for drilling development wells in Sahmah field of block 7, in the south east of Oman. Integrated Drilling Services (IDS) provider in Oman was awarded a contract to drill 10 firmed wells for a national client. One of the most challenging environments in the surface section is to drill and cement highly fractured and caved carbonate formation (UER) which prone to losses as this play a major risk and later deal with problematic shale formation in the same section. Moreover, the client decided to change the scope of some of the development wells and go for exploration pilot hole exploring deeper horizons to evaluate other potential hydrocarbon zones. The engineering team have the opportunity to study the field in depth. As a result of analyzing offset wells data, geological and geomechanical studies, a new well design has been proposed which eliminates one section of the previous well design which was executed on some of the offset wells before. In the same proposal, the intermediate casing setting depth was been extended deeper successfully to accommodate the changes in the scope to explore deeper horizons. The new proposed well design achieved reduction in well construction time and cost for the client enabling reduction in overall Authorization for Expenditure (AFE). This enabled the introduction of new technologies which improved performance. The drilling design consideration process in this paper can be used to provide a valuable insight for future projects where complex technical study in advance is the key to success.