Economic feasibility of drilling horizontal wells in a shallow high permeability coalbed methane reservoir.

摘要

Coalbed methane (CBM) reservoirs have emerged as an important source of natural gas production. However, the choice of drilling configuration employed differs from basin to basin. The Powder River Basin coal seams shallow nature is believed to favor the current vertical well configuration.;Horizontal well drilling in CBM reservoirs has been studied in deep and thick coal seams like the Appalachian and Cherokee Basins in USA, but little work has been done in shallow CBM reservoirs like those of the Powder River Basin. The objective of this thesis is to use a reservoir simulator and economic analysis to study the economic feasibility of drilling horizontal wells in shallow CBM reservoirs such as the CX field Monarch Coal seam of the Powder River Basin. A dual porosity reservoir model was built and historical production was matched. The resulting simulator was used to run different configurations of vertical and horizontal wells. Economic analysis was then performed on the simulated productions to determine the optimal drilling strategy. Additional cases of different permeability values and thicknesses were also considered.;The results show that horizontal wells would not be economical when compared to vertical wells in shallow coal seams. The results of this work were based on current natural gas prices and drilling and operational cost.