Publications

Coal Bed Methane (CBM) is a natural gas containing close to 100% methane (CH4) produced from a coal seam reservoir. It is natural gas that is sourced and reservoired within a coal seam. CBM is often produced at shallow depths and is often associated with large volumes of produced water. Comparing CBM projects with conventional oil or gas operations, water production and disposal assumes a greater degree of importance in CBM projects. Water disposal costs are a critical factor in the investment decision of marginally economic CBM projects. It would be significantly high particularly if there is a lot of contaminant in the produced water. In this case, water disposal costs can make or break a marginal project. One of possible techniques to dispose the produced water is by injecting it into subsurface reservoirs separated from the producing coal seam. Sufficient reservoir quantity and quality is required to dispose of the produced water. A good understanding of reservoir distribution is needed for initially screening areas of high potential area for injecting produced water during the development/production stage. One of methodologies used to understand sandstones distribution is to determine the depositional environment for the sand. This study is based on analyses of 2D seismic and well data. This project involved well to well correlations, seismic horizon interpretation, and seismic facies analysis, which lead to interpreting sand-prone facies distribution as a model of the depositional environment. Conventional exploration wells in the basin proved that Eocene Tanjung Formation has sandstones development. These sandstones reservoirs have been identified as one of the candidate for the CBM water disposal targets in the Barito Basin. These reservoirs were predominantly deposited in a broad * BP Indonesia coastal plain. A depositional environment model was proposed with three identified subenvironments, fluvial, coastal plain and shallow marine. Potentially thin sandstones, with widespread distribution were identified for water disposal. Keywords: CBM, water disposal, depositional environment model.