Title: Optimization of Well Length for Horizontal Drilling
Author(s): Hyun Cho, Kellogg Root and Brown, Inc., and S.N. Shah, The University of Oklahoma
Journal: Journal of Canadian Petroleum Technology, Volume 41, No. 5, Page 54
Abstract: As the length of a horizontal well is increased, its drainage area also increases. Productivity of a long horizontal well is no longer proportional to the well length, because an increase in the length of the horizontal production section also causes frictional losses in the wellbore. However, no reliable standards are currently available that take into account quantitatively the parameters necessary for the determination of an optimum well length for horizontal drilling.
A new approach of the specific productivity index is proposed to predict the production rate, considering friction losses in a long production section under inflow conditions. This specific productivity index is derived by assuming steady-state flow of a slightly compressible fluid in an anisotropic formation. This paper presents a methodology developed to obtain the optimum horizontal well length based on total economics as well as productivity index (PI) change associated with frictional loss effects in the long section of the horizontal wellbore. An integrated approach is proposed for quantitative analysis of the parameters affecting productivity and economics, in order to achieve the overall optimum performance of a horizontal well project.
