Cost Optimization at Design Stage by Implementing Barefoot Completion in Carbonate Reservoir

Abstract

Most of carbonate wells in PETRONAS Carigali Operated blocks in Malaysia are completed with pre-drilled liner. Barefoot completion is a new approach that is planned to be implemented in this particular carbonate field. This paper aims to share on how selection of lower completion based on in-house carbonate lower completion guideline could optimize overall well cost. The offset well in X field are all completed with pre-drilled liner. As an initiative to further optimize the well cost and delivering an economic field development plan, barefoot completion has been proposed as a completion strategy for the upcoming drilling campaign. Selection of this strategy has taken into account the wellbore stability during production, geochemical effect and critical drawdown, including unconfined compressive strength (UCS) based on the outcome of the geomechanical study. The advantages of the approach are mainly in reducing open-hole length thus reducing the drilling cost, secondly is eliminating all the equipment requirement for lower completion thus reducing completion cost by 14% in X field. This shows that the guideline is effective in choosing the fit for purpose and safe lower completion strategy for carbonate. The work evolved from replication of best practices and lessons learnt from the developed fields in Central Luconia. Complimentary to the existing in house completion selection guideline, the new guideline for carbonate lower completion and its implementation in this design has contributes by minimized risk uncertainty in developing carbonate reservoir to a controllable level, thus becoming reference for future similar development within PETRONAS.