Brown Field Optimisation to Maximize Gas Recovery in Muda Central Field of Joint Development Area, North Malay Basin

Abstract

Finding an opportunity to expand the recoverable reserves in a brown field is always a challenging task. A robust reservoir characterization and dynamic synthesis are vital to provide a proper understanding of the field. The objectives of this project are to maximize gas recovery through 3D reservoir modeling works, to evaluate un-connected hydrocarbon volumes, production improvement, and prudent reservoir management. Muda Central field (MCF) has been producing for more than 5 years with 40 production wells. Therefore, the production data is an essential input to assure the quality of the model. The geological-facies modelling was constrained by seismic attributes as quantitative soft data after calibrating to well data. The high uncertainty of reservoir presence in the model was assessed by combining sand distribution and porosity variation. Material balance analysis was used to select a base-case static model in order to reduce the iteration process during the history match. History matching was performed with a reasonably good match to calibrate the model. The results of dynamic simulation indicated some potential undrained hydrocarbon areas that are promising for future development. As a result, one well was proposed to appraise and prove the existence of disconnected hydrocarbon volume as recognize in the seismic attributes. The well was drilled a year later to prove the hypothesis. The drilling result demonstrates that the initial hypothesis is proven by pressure data and fluid sampling. The reservoir pressure is still un-depleted and the level of CO2 content is different compared to the existing producing wells. This finding provides an opportunity for future development in the vicinity of the existing producing platform as well as a different development scheme in the area of the appraisal well. The additional benefit of this work is to assist with prudent reservoir management. A comprehensive model of MCF demonstrates a best practice, collaborative interaction between geophycisist, geologist, and reservoir engineer. This study successfully proved disconnected hydrocarbon volume, which translates into a future development plan to optimize MCF reserves.