Economic viability of multiple-lateral horizontal wells

Abstract

Horizontal wells are gaining popularity throughout the petroleum industry as a means to increase well productivity and enhance incremental economics. Horizontal wells provide greater reservoir exposure and are useful in intersecting additional pay zones as well as natural fractures. The objective of this study is to determine the relative attractiveness of horizontal wells with multiple-laterals compared to single-horizontal wells based on well performance modeling and economic evaluation. It will focus on the application of multiple-lateral horizontal wells to reduce the risks of economic uncertainty associated with poor reservoir characterization in areally anisotropic reservoirs. Using a state-of-the-art productivity index model, the study will demonstrate the productivity advantages of multiple-lateral horizontal wells and then determine the economics based on incremental net present value as compared to single-horizontal well completions. This paper will first discuss the development of the productivity model used in this research. It will then discuss the advancements of steady-state, pseudosteady-state and transient models which have led to the current understanding of horizontal well productivity. Next, it will combine the previous works on horizontal well candidate screening into a coherent approach to drilling a horizontal well. It will identify and discuss the governing variables for the success of a horizontal well project. It will also stress that conducting parametric studies is important to optimizing the horizontal completion. Horizontal productivities will be compared to other completion options. The next decision is what direction to drill the horizontal well. This paper will show the critical impact of well orientation on horizontal well performance in areally anisotropic reservoirs. Little effort has been made to determine horizontal permeability magnitudes and orientations in the field. This paper will demonstrate the large risk of economic uncertainty involved in not knowing these directions and demonstrate the need for additional reservoir testing. This can determine the economic success or failure of a project. Finally, the paper will demonstrate a new application using multiple-lateral horizontal wells to reduce the risk of economic uncertainty in areally anisotropic reservoirs while increasing the incremental net present value over existing single horizontal wells.