As part of a coiled tubing drilling re-entry campaign for a client in the Middle East, a well required a through-tubing casing exit system to enable the subsequent drilling assembly access to drill a new lateral. On completion of the drilling phase, a production well test determined that water production from the lower perforations in the main bore had increased to an unacceptable limit, and a water shut-off solution was required.
The paper will provide a comprehensive overview of utilizing a through-tubing whipstock system deployed with coiled tubing in order to create an effective window in the production liner. One of the major advantages of a coiled tubing deployed exit system is the ability to mill a window in the casing in a restricted wellbore environment. The whipstock can be deployed into a live-well environment without the necessity of removing the completion equipment, thus eliminating the requirement for a workover rig or potentially reservoir-damaging well kill fluids. The paper will also focus on the use of through-tubing inflatable technology and the relationship of utilizing these unique devices for water shut-off applications.
The case history will detail the running of a new exit system showing the economic benefits of utilizing live well intervention deployment methods for whipstock placement as well as the rig cost savings of utilizing coiled tubing deployed mills and motors for delivering a casing window. The case history will also detail inflatable technology for water shut off applications for this particular well focusing on the ability to run and set the inflatable device in a cross-flow environment.