Operational Excellence in Qatar's First Successful Rigless Heavy Duty Wireline Fishing in a Qatargas Offshore Unmanned Platform

摘要

Qatargas North Field wells are typically 7 inch monobore medium to high deviation wells and are designed to handle high pressure sour gas containing of H2S and CO2. An extensive rigless well intervention program is carried out with 0. 23 inch electric line and with 0. 125 inch slickline for data acquisition, and for other downhole wireline jobs. During a rigless PLT operation with 0. 23 inch e-line, an accidental closure of the TRSCSSV resulted in cutting of the e-line. This necessitated a rigless heavy duty wireline intervention resulting in a successful, safe and a cost effective fishing operation in recovering 11, 414 ft of 0. 23 inch braided e-line. This paper describes the approach and the technique applied in the fishing operation considering the limitations of a rigless operation. It also outlines the extensive workshop trials carried out during the preparatory phase for developing an acceptable double block and bleed barrier arrangement on the PCE for a safe well intervention. It also describes the planning considerations, the procedures developed, the high level Risk Assessment carried out, and the elaborate Load Assessment Study for working with a 90 ft mast and 0. 23 inch braided line on a remote un-manned offshore platform.