| Popis: |
The case studies performed in the Middle East and South Asia region shared in the paper reflect the requirement of production/injection enhancement in challenging downhole conditions. Larger tubing diameter, limitations of minimum ID to deploy bigger OD tools, low bottom hole pressures, and requirement of high annular and jetting velocities are often demanded in CT clean-out operations. The advancements in coiled tubing metallurgies to intervene in complex wellbore geometries and the precision of downhole simulators to predict on-site scenarios have put more pressure on the efficiency of downhole tools in production enhancement services. Thus, the case studies required a tool that could overcome the barriers offered by incumbent technologies. It is confirmed from laboratory tests that a standoff of eight times the orifice diameter and fluid velocity of 200 ft/sec is required to remove moderate to hard deposits from wellbores. Conventional jetting tools have a standoff distance of more than 40 times and fluid velocities are far below 200 ft/sec thus objectives of CT intervention are often compromised. Moreover, the effectiveness of conventional tools for critical matrix in the stimulation operations is barely minimum as the jetting effect diverges from the jetting stream. A new type of fluidic oscillator was utilized in the case studies. Unlike pulsating effects created by 1st generation of the fluidic oscillators, the SFO type oscillator had triple jetting action namely, Helix jetting, Pulses Jetting, and Cavitation jetting which was equally effective for in-wellbore and near- wellbore regions. Paper also explains the working mechanism of the tool and demonstrates its ability to remove the skin in the critical matrix The results of the clean-out with SFO technology were beyond expectations. It reduced the operating times to two-thirds of conventional operations, which led to cost savings in all the case studies by an average of 35%. Moreover, it increased the efficiency of treatment fluids which resulted in the reduction of waste of additives, and the requirement of extra efforts to dispose of excess materials at wellsite. Also, jetting effectiveness caused an increase in production/injection from 30%- to 250% This is the first technology that uses cavitation jetting in oilfield services and the first to use aforesaid jetting actions altogether in one tool. The technology adopted in the case studies doesn't have moving or rotating parts, thus eliminating the requirement to pull CT out of the hole for redressing and can perform long operations in one go. It doesn't depend on the centralization of the tool as the jetting effect is passed via kinetic energy through submersed fluids, thus can target deeper depth without limitations of the standoff. It allows a higher flow rate of liquid and gas, thus offering higher energies for clean-out and stimulation operations. |
