New Type of Fluidic Oscillator Made Clean Out Operation Environment Friendly and Cost Effective – A Case Study that Converted Failure into a Success

Abstract

Abstract Untreated disposal of effluent water has the potential of scaling and plugging the in and near-wellbore regions. A case study and methodology adopted for the clean-out operation of water disposal well of Khurmala Field of Iraq is analyzed in the paper. Previous attempts of clean-out using high-pressure hydro- jetting tools along with acid treatment proved futile effort. As last resort, Fluidic Oscillator (SFO) was deployed for clean-out to regain access of TD and plugged fracture network before the eventual decision of work-over is made. Combination of SFO having pulsing, cavitation, and helix jetting action in conjunction with train of fluids consisting of diesel, 28% HCl and gel were utilized. The operational sequence of clean-out was in stages of 10m to clean 79m interval, comprising of slotted liner and open hole, filled with detritus. Low bottom pressure required a dynamic approach for treatment-fluid nitrification based on the success of clean-out and access to liner and open hole. Annular velocities required nitrification once the slotted liner and open hole were open for in-take. Rate of penetration, sequence and volume of fluid-trains, nitrification, and batch cycling were designed in accord to changing downhole dynamics during clean-out. A thorough investigation of detritus, designing of fluids, the accuracy of downhole hydraulics, and application of SFO proved to be an effective solution. It regained access to TD and connectivity between the wellbore and the injection zone. Injection increased from none to 15 bpm at 200 psi. The combination jetting effect of SFO (acoustic pulse (alike), cavitation, and helix) demonstrated to be more effective than rotating jetting tools. Moreover, the merits of operational efficiency supplanted conventional operations and environmental impacts were considerably low in terms of operating time, spent additives, and avoidance of work-over operation. The matching injection parameters post-operation with native parameters post-completion indicated that detritus is removed from wellbore and damage from the critical matrix is removed/bypassed. Currently, SFO is the only technology that has pulse, cavitation, and helix jetting structures. It has an effective jetting for in and near wellbore region while the kinetic energy transferred via fluid makes the impact stronger in the deeper region. The internal mechanism of the tool allows it to handle high pumping rate and pressures while external finishing offers multi-port orientation for outflow that allows targeting the fill in desired directions. The tool does not require redressing, thus it proves to be an efficient, safe, and cost-effective alternative