Optimal RDIF & Breaker Design for Horizontal SAS ICD Completions: A US Gulf Coast Land Case Study

Abstract

Abstract Achieving stable laterals for successful deployment of ICD sand screens with swell packers can prove difficult in Southeast Texas reservoirs due to hole instability, tight ECD margins, high clay content, and varying permeability contrasts. Historically, bore hole instability has resulted in unplanned sidetracks and difficulty landing sand screens at target depths. A unique engineered solution for this US-Land open-hole completion tailored to the specific well conditions was utilized with great success to overcome these challenges. A reservoir drill-in fluid (RDIF) utilizing a divalent brine was developed to optimize the drilling and completion processes and deliver a stable, gauged hole. The fluid density was determined using a mechanical earth model and sized calcium carbonate was used to yield a thin and pliable filter cake. An in-situ organic acid generator with enzymes was formulated with the RDIF to mitigate near-wellbore damage while achieving uniform filter cake removal during the completion phase to reduce screen plugging. The fluid formulations were validated by laboratory testing. A detailed procedure ensured the fluids were maintained within design specifications throughout the execution phase. The four well program was executed with no stuck pipe events or unplanned sidetracks due to hole conditions resulting in the following results and observations: Based on a newly developed mechanical earth model (MEM), the mud weight was kept to a tight 0.5 lb/gal window to limit pressure fluctuations and resulted in a stable gauged hole Successful screen deployment was achieved after conditioning the RDIF using solids removal equipment and RDIF dilution. The final drilling Bottom Hole Assembly (BHA) was run on elevators without the need for pumping or rotation LWD caliper showed a gauged hole with no breakout along planned completion interval. Prevention of fines migration was achieved utilizing the brine-based RDIF optimized utilizing formation minerology from the core and based on production results. Maintaining Methylene Blue (MB) levels in the RDIF was achieved on location through mud dilution while drilling. MB levels were set based on lab return permeability results. Shale inhibitor concentrations were maintained to address the interbedded shale and clay content in this sandstone reservoir. Comprehensive cleaning of tanks and lines to ensure filtered brine with low nephelometric turbidity unit (NTU) measurements and breaker components did not get contaminated. Sand retention and screen plugging tests were carried out utilizing core material to ensure a good well cleanup. Tracers run in the screens showed the wells had fully unloaded to TD and indicated good uniform inflow. Having a stable gauged hole allowed the screens in these second-generation wells to be deployed to TD, resulting in a twofold increase in average completed lateral length, and enhanced well PI and deliverability. The present paper provides an overview of the technical difficulties presented by the challenging geological conditions of the Frio Sands, examines the extensive laboratory testing conducted to ensure a successful solution in US land in a conventional reservoir environment, and summarizes the field execution and outcome, along with the key takeaways and lessons learned.