Best Practice of Well-Reservoir Management Approach in Gas Field with Integrated Production System Modeling
Abstract
Arar block in Salawati basin, onshore West Papua; comprises of nine (9) gas fields which are producing from Miocene-Kais reefal limestone since 1983 from more than 20 wells. The gas production peak was achieved at 32 MMSCFD in 1995 from two major gas fields, namely Arar and Klalin before sharp production decline due to great escalation of water-gas ratio occurred in Klalin field.
Most of the gas production is exported for sales corresponds to the ongoing gas contract thus sustainable gas plateau is critical to ensure sufficient gas supply to the market. In order to secure the production plateau, four (4) new gas fields were hooked-up to the gas production system in late 2008 resulted to more stable gas plateau rate about 21 MMSCFD till today. The strategy had given advantage for Klalin field in order not to push the withdrawal rate from the reservoir for the sake of stable production plateau.
Integrated Production System Modeling (IPSM) was constructed recently in PetroGas (Basin) Ltd (PBL) that considers the production of hydrocarbons from PBL gas reservoirs through the surface facilities, in a single integrated model that includes the reservoirs,
wells, processing facilities and export pipelines with the topside constraints (e.g. wellhead chokes, separator, compressor capacity). The components of the model should be sufficiently accurate to represent the behaviour of the system at least in terms of pressure and rate. Hence IPSM can evaluate the impact of different reservoir outcomes and subsurface development decisions in combination with surface facilities options to meet the requirements of well and reservoir management minimum standard.
In PBL, the IPSM has been used to provide answers to pertinent development and production concerns for gas fields to accommodate projected future gas demand. No less importantly, it is also utilized in daily operation to performance under wells and reservoirs safe operating envelope as well as network system optimization.
