Generative Well Pattern Design Applied to a Giant Mature Field Leads to theIdentification of Major Drilling Expenditure Reduction Opportunity

摘要

Well pattern design is difficult due to the very large number of possible solutions,the complexity ofconstraints deriving from drilling and completion,the nonlinear nature of fluid flow in porous media,thedifficulty in ascertaining reservoir properties and,for mature reservoirs,development history.What mattersthe most is case dependent.This task is therefore traditionally conducted through manual processes withlittle or no help of computers,leading often to exceedingly conservative or simplistic designs whatever thereservoir heterogeneities.The increase in computational power and algorithmic advances are opening the door to a new"GenerativeDesign"approach,already used by other industries(car,aerospace).It consists in exploring a largernumber of computer generated design possibilities more quickly and efficiently than what human can do bycombining:i-"technical and experience"rules to automatically build a large number of"designs candidate",ii-workflows that qualify the performance of the designs,iii-selection criteria to identify the best design(s).An innovative Generative Well Pattern Design Workflow named GWPD-WISH was benchmarkedagainst traditional"manual"designs to leverage three reservoir development planning opportunitiesapplicable to a giant mature middle eastern carbonate field already developed by hundreds of wells forwhich a reliable model was available:1.Locate 2×15 in-fill producers to be drilled from 2 freely chosen platform locations.2.Locate 2×15 in-fill producers to be drilled from 2 pre-determined platform locations.3.Select 16 multi-string water injector wells for re-drill to improve recovery through better controlof local reservoir pressure balance.The study was conducted using a large operational compositional model considering complex constraintsin a limited time.The workflow proved able to identify substantially better patterns than the traditionalapproach for each of the three opportunities at the costs of only few hundreds of simulations.Patternimprovement was measured in term of reserves per incremental well and plateau duration extension.Itcorresponds to an opportunity for reducing drilling expenditures on a rolling basis by 30% or more.