Well-bore Collision Risk Evaluation And Its Application

Major part of oil and gas fuels is acquired from subsurface reservoir via drilling.Although,vertical drilling needs simple technology and,ultimately,low cost.However,directional drilling must be used in order to reach inaccessible territory,to drill more wells from single platform,and to side track an existing well.We describe current industrial technologies available for Measurement While Drilling(MWD).MWD magnetic based technology and the various challenges that face magnetic sensors also are discussed.Moreover,we present an up-to-date development of the MWD gyroscope based technology.We introduce the concept of well positioning,which is used to estimate the position coordinates of the points in petroleum based on MWD measurements.We also find the statistical distribution of the NEV coordinates of the survey points in a petroleum well,by using error propagation.In this work,we use statistical techniques in order to express risk of collision between two wells.We introduce and formulate collision avoidance to investigate collision between reference and offset wells.In addition,we propose more exact way of hypothesis test,which turns out to be more conventional than original one.Alternatively,we can find risk of collision by approximating probability of collision.This test is carried out by taking merely two closest points.Eventually,Case study from Shengli oil field is tested with renowned software named Halliburton Landmark’s Compass.By applying well-bore anti-collision implementation process we conclude that existed well 01-Y45-X16-Y45-X16 wells has no risk of collision with planning wellpath of P25-A due to separation factor greater than 1.5.However,well 01-Y45-X15-Y45-X15 may collide with planning well path P25-A due to Separation factor less than 1.5.Now,we have to plan wellpath again by keeping TVD and horizontal distance constant as Planning #1.By altering the KOP,Build-up rate,and ultimately,drop down section direct the drill bit to pay zones.