COIL TUBING FISHING OPERATION ON A DEEP, HIGH-PRESSURE, SOUR GAS-WELL

The use of coil tubing in fishing operations has been limited to date. This paper discusses a coil tubing fishing operation on a 4000 m, 30% H2S gas well with 27 MPa surface pressure. A 12.5 metre wireline tool string was stuck inside the production tubing at 1770 m, with 76 m of elemental sulphur fill on top. The need for 23 m of lubricator during coil tubing fishing operations was eliminated by designing a pump thr ough Pressure Deployment System, along with a pump-off sub. Problems e ncountered with the Pressure Deployment BOPs will necessitate periodic inspection of the BOP stack on future high pressure, sour well work. Advances in coil tubing technology have made coil tubing an economical alternative for many oil field operations. Fishing operations can now be performed on live wells without long sections of lubricator. Coil tubing has increased to 88.9 mm (3 1/2'') in size, has become more H2S resistant and is now continuous without butt welds. The components of the coil tubing unit, such as the injector, have also increased in st rength allowing work in deeper and higher pressure wells.