A Detailed Evaluation of Coiled Tubing Drillouts of Composites andDissolvable Plugs In Permian Basin and Eagle Ford Fields

摘要

Coiled tubing(CT)operations in Texas are distributed in the Permian Basin and Eagle Ford plays supportingunconventional completion of horizontal wells using plug-and-perf technology.CT drillouts are a key step inperforming the plug removal and achieving full production potential.From a wide variety of plugs available,the most common plugs are composite and dissolvable.This study presents an evaluation of both plugs forCT drillout.The analysis gathers post-drillout data from CT interventions in the Permian basin and the Eagle Ford:63 wells completed exclusively with 2,664 composite plugs,60 wells completed with a combination of bothtype of plugs for a total of 382 dissolvable plugs and 1,792 composite plugs,and 16 wells completed with543 dissolvable plugs.Data were analyzed for correlations between well geometry;lateral length;plugsused;dissolvable plug location in the lateral(heel,toe,full lateral);and key performance indicators(KPIs)such as time in well,average milling,wash times,plugs spacing and total number of plugs.The evaluation was conducted by comparing wells completed with only composite plugs,onlydissolvable plugs,or a combination of both types,and it included a review of dissolvable plug dissolutionperformance.Composite plugs show a consistent milling performance for laterals of 1 and 1.5 miles,with anaverage milling time of 4 to 5 min and a variance of 3 min and wash times of 26 min;for laterals longer than1.5 miles,the performance declines.When evaluating laterals completed with dissolvable plugs averagemilling time is 7 to 9 min,and the variance increases with the lateral length,with wash times of 26 to 36min.Wells completed with a combination of dissolvable plugs on the toe and composites in the rest of thelateral show an improved overall performance,with constant milling times of 4 to 5 min regardless of thelateral length and variance of 1 to 3 min;the overall time in the well when plugs are combined is reduced by46% compared to laterals completed with dissolvable only.The analysis also determined that at least 45%of dissolvable plugs did not dissolve and required CT intervention.The aim of this is study is to give operators a tool to assess the costs and benefits of using different plugtechnologies with a strategic placement to execute interventions in the safest and most efficient manner.Additionally,dissolvable plugs are commonly associated with cost reduction related to eliminating the needfor CT milling.However,the data shows that inconsistent dissolution of the dissolvable plugs adds anuncertainty factor,which can only be dissipated with intervention using CT.