Abandonment Best Practices in Unitised Area for Wells and Facilities Straddling Two Countries in Malay Basin: A Case Study

Abandonment is considered to be the last stage in the oil gas field cycle. Oil and gas industries around the world are bounded by the necessity of creating an abandonment program which is technically sound, complied to the stringent HSE requirement and to be cost-effective. Abandonment strategies were always planned as early as during the field development plan. When there are no remaining opportunities left or no commercially viable hydrocarbon is present, the field need to be abandoned to save operating and maintenance cost. The cost associated on abandonment can often be paid to the host government periodically and can be cost recoverable once the field is ready to be abandoned. In Malaysia, some of the oil producing fields are now in the late life of production thus abandonment strategies are being studied comprehensively. The interest of this paper is to share the case study of one of a field that is in its late life of production and has wells and facilities that planned to be abandon soon. The abandonment in this field is challenging because it involves two countries, as this field is in the hydrocarbon structure that straddling two countries. Series of techno-commercial discussion were held between operators of these two countries to gain an integrated understanding of the opportunity, defining a successful outcome of the opportunity and creating an aligned plan to achieve successful abandonment campaign. Thus, this paper will discuss on technical aspects of creating a caprock model, the execution strategies of abandoning the wells and facilities and economic analysis to study whether a joint campaign between the operators from two countries yields significantly lower costs or otherwise.