Publications

In many cases, shallow gas development is associated with drilling hazards which frequently result in a shallow gas kick. This shallow gas mostly takes the form of biogenic gas, which is the product of microbial processes. The gas is easily recognized through an amplitude anomaly—a bright spot in seismic data—and in some cases, the gas reservoir is spread widely enough to create a big accumulation for gas commercialization. One of the successful examples of shallow gas field development in Indonesia is in the Bentu PSC area, located in Riau Province. The gas reservoir is deposited between 1,000 and 2,500 feet below the surface, structurally trapped in sandstone reservoir rock in a multilayered zone, and containing sweet gas with a methane content of up to 99%. This biogenic gas field has been producing gas for more than 10 years, starting at 20 MMSCFD and then ramping up to 90 MMSCFD. During the 10 years of production, many field experiences, challenges, and milestones have occurred. They include studies of reservoir characterization and typing, reservoir volume estimation, well-completion strategy, and challenges in production. The methodologies used in the evaluation are based on field observation, statistical wells and reservoir performance, and the integration of geoscience and engineering data for a more thorough evaluation. All the sweet and the bitter stories during the 10 years of production experience will be shared statistically in this paper, which hopefully will provide additional knowledge and contributions to others interested in developing and unlocking shallow biogenic gas potential in Indonesia or even elsewhere around the world.