Publications

Probability of success for coiled tubing (CT) cleanout operations in high deviation, thru tubing wellbores for Chevron in Kalimantan, Indonesia, was low. This technical and operational challenge was compounded when faced with large casing and low bottomhole pressure.Direct circulation using the gas lift system produced returns in batches. Reverse cleanout using fluid resulted in a stuck pipe incident, and direct foam circulation was both expensive and complicated when coupled with offshore logistical challenges. All of these techniques were considered inappropriate.After developing and evaluating alternatives, an innovative cleanout method was proposed. Using the available gas lift in conjunction with a CT deployed, real-time monitoring system, the focus shifted from surface monitoring to real-time downhole measurement. This enabled optimum decision-making during the execution phase of the cleanout.Two cleanout operations were performed utilizing real-time downhole measurements coupled with an innovative high efficiency fluid and jetting assembly. Both well configurations involved cleaning out 9 5/8-in casing though a 3½-in production string at depths in excess of 8,000 feet and deviations of 60 and 90 degrees respectively.Utilizing fiber-optic acquired data enabled an optimum cleanout of fill across the low pressured reservoir. Losses were minimized, (while maintaining fill removal to surface), by maintaining the bottomhole pressure at balanced condition while regulating surface choke and gas lift injection rates. Additionally, access to real-time, fiber-optic transmitted CCL data enabled accurate target depth correlation, minimizing multiple tags runs.All job objectives were met within the scope of the campaign while the proven success has opened numerous additional candidates.This paper will investigate and discuss in detail the challenges, alternatives, and proven solution to cleaning out low formation pressure wells.