Optimization of Coiled-Tubing Acidizing Through Real-Time Staged Fluid Tracking

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn coiled tubing acidizing, a variety of fluids are pumped through coiled tubing in certain sequence to create the optimized downhole condition to treat the wellbore. Typically, prior to the coiled tubing reaching the target treatment zone, a neutral fluid may be pumped into coiled tubing during running-in-hole (RIH) for circulating purpose. Once at the targeted treatment zone, a pumping schedule (such as pre-flush, treating and postflush fluids) may be used to treat the wells. During the operations, the coiled tubing operator may also move the coiled tubing (either running-in-hole or pulling-out-ofhole) while staged fluids are being pumped. It is desirable to track the movement of staged fluids inside coiled tubing to optimize the treatment. This paper presents a new technology to track the movement of stage fluids inside coiled tubing. It includes real time surface and downhole measurements, fluid and gas modelings and friction pressure drop calculation along coiled tubing. This new technology allows operators to optimize coiled tubing running speed and surface pumping to create the desired action downhole. The availability of staged fluids information downhole also opens the possibility for real time treatment evaluation. Several field job cases are reviewed to demonstrate the effectiveness of this new technology.