Efficient open-hole logging of the horizontal wells using openhole tractoring. Field experiences from TATWEER petroleum company-Bahrain

Horizontal drilling is fast becoming an effective economical solution to maximize the asset value for E & P companies. Since established in 2009, TATWEER petroleum is one of those companies that utilize horizontal drilling intensively to improve the production and the recovery factor from tight and fractured carbonate reservoirs within the Bahrain Field. Reservoir complexity and heterogonity create the need for running open-hole logs in most of the horizontal wells within the Bahrain field. Logging is essential for the following: Designing the well completion (Open hole or Slotted liner equipped with external packers), predicting and understanding the well performance, and planning future work-over activities (Water and Gas Shutoff). Normal practice to deploy open hole logging tools into the HZ horizontal section within the Bahrain field was to use drill pipe (Tough Logging Conveyance). Given the typical low productivity of wells, operational costs were of concern. Consequently, TATWEER requested alternative methods to optimize the logging operations in horizontal wells. Of the options offered by Schlumberger, tractoring technology was deemed to be best. The main challenge faced initially was with tractoring in the low uniaxial compressive strength (UCS) of the reservoir formations (UCS=1400-3000 PSI) in Bahrain. Since tractoring is known to be an effective deployment method for hard formations (UCS>5000 PSI), the new OH tractoring technology (UltraTRAC^∗) was offered by Schlumberger as a solution for this low UCS enviroment. UltraTRAC^∗ was successfully deployed in TATWEER wells, saving 60-70% of the logging time comparing to the normal TLC (Tough Logging Conveyance) operations which represents 5% saving of the total well cost. In this paper, the authors discuss the details of this new logging methodology, logging results, and value obtained from using this technology.