The Effect of Some Coalbed Methane Properties on Deep Thick and Shallow Thin Coalbed Methane Reservoirs

Abstract

Recently, the industry has moved toward unconventional gas reservoirs to supply their demand of the energy. The unconventional gas reservoirs are new source of the energy in the world and especially in the United State of America (USA). The unconventional gas reservoirs are trapped in impermeable rock which cannot migrate. These gas reservoirs can be classify into Tight Gas, Coal Bed Methane, Shale Gas and, Methane Hydrates. Among these types of reservoirs the CoalBed Methane (CBM) covers the largest area in the USA. Some areas have been discovered and others not yet. Each area has different reservoir characteristics start with reservoir rock properties such as coal thickness and end with reservoir fluid properties such as gas content. As a result of discovering coalbed methane reservoirs (CBMs), many studies of understanding reservoir properties have been covered fairly. However, each study covers specific area of CBMs and specific reservoir characteristic. Moreover, the most challenging task for reservoir engineers is to understand of how the fluids flow in the porous media and how each reservoir parameter effects on the flow. This can be achieve by using reservoir engineering tools which provide a great view to engineers of how the fluid flow through the coal porous media. Some studies focused on deep CBMs but not thick or thin CBMs but not shallow. As a result, this study has been chosen to covers the effect of some reservoir properties on the gas production of deep thick and shallow thin CBMs. This can be accomplishing by building two reservoir simulation models for deep thick and shallow thin CBMs, to study the effect of some reservoir parameters. Four reservoir properties have been chosen in this study. These reservoir parameters are; Coal Permeability, Coal Porosity, Gas Content, and Desorption Time. The chosen of these reservoir parameters is because they have the most effect on the gas production of CBMs. Each reservoir parameter will be investigated individually when coal is deep thick and when coal is shallow thin. In the end, comparison between the obtained results will illustrate whither the deep thick CBMs has more influence on the gas production than shallow thin CBMs or not.