The importance of correct placement of horizontal wells and their actual drainage area for field development plans

Abstract

Over the last two decades horizontal well types have become more favorable than vertical ones due to maximized reservoir contaact and an increased productivity index. While the initial costs are still higher the overall recovery rates due to the higher drainage area and delayed water coning effect make them more desirable for field development plans. To further optimize field development plans and reduce costs, the Effective Horizontal Length (EHL) and the overall Effective Drainage Area (EDA) of wells were investigated in detail. During this study it emerged that - although various scientists have accounted in their approaches for the pressure drop along the horizontal section of the well - the established commercial simulations programs still use Joshi's assumption of a cylindrical drainage shape instead of a conical one. This result in a simulation error, which has a substantial impact on field development plans and the way horizontal wells are planned today. The conical shape stems from the fact that the highest pressure differential occurs at the heel of the well, instead of an equal distribution from heel to toe, which has been confirmed by the use of production logging tools and underbalanced drilling data. Consequently, this study proposes to update the simulation models and ensure that future wells drilled already specify in the well proposal the direction of the horizontal section to maximize the sweep with a minimum of infill wells. With over 2500 wells drilled in the next 5 years this would result in potential savings of over $1billion and 9000 days

Date of Award	2012
Original language	American English
Supervisor	Hadi Belhaj (Supervisor)