Implementation of a New Risk Based Well Collision Avoidance Method

摘要

A majority of industry operators and service companies haveadopted directional drilling collision avoidance rules based onstringent controls to prevent surface collisions and consequenthuman and environmental damage. These rules are found to beseverely restrictive for the optimal positioning of wellsthrough deeper reservoir zones where the level of damagefrom collision can be contained.A new method is proposed that retains existing rules foravoidance of shallow (severe outcome) collisions and providesthe option for use of risk based rules in deeper sections ofwells where the outcome of a collision would not be as severe.The risk level of collision with respect to any offset well iscalculated and then converted to a Risked Clearance Factor, anestablished standard for evaluating different levels of collisiontolerance in wells.Deep intersections have several characteristics whichrequire separate treatment from shallow intersections. Theyhave high convergence angles which minimize the physicalspace and distance where a collision may occur and they havelower economic risks of a collision relative to the cost ofcorrective action.This method has been implemented in a field area of rapidprospect planning and development. The rules are designed tobe simple and practical in order to reduce planning anddrilling cycle time. A matrix of risk elements, specific to thefield area is presented for different depths of collision to helpto derive the level of tolerable risk. A case history ispresented that shows the clear benefit of utilizing the alternatemethod.