An Improved Method of Slickline Perforating

Abstract The BP North Sea Southern Business Unit has successfully incorporated the Schlumberger eFire* electronic firing head system with conventional slickline equipment and perforating guns during a recent trial. Significant benefits were achieved with this system by completing runs quickly and eliminating time-consuming and costly ‘parameter' runs by using conventional memory tools for correlation. The conventional tools were run within an empty perforating gun housing. During this run the wire was ‘flagged’ at the desired depth and a pass was logged. When logging tools were retrieved and their measurements downloaded, a ‘Tie in Log’ was produced. This was used to correlate the flag on the wire to the ‘Reference Log’. Then 2 7/8-in. HSD* High Shot Density PowerJet* perforating guns were run in hole to the predetermined ‘flag’ depth, and a firing command was sent to the eFire device. The eFire-Slickline system is an electronic firing head developed for slickline deployment. It is operated by a coded sequence of tension pulses on the slickline wire, which is converted to pressure pulses by a strain sensor in the tool. Following perforating, a ‘disarm’ command is sent and the perforating guns are then pulled out of hole. Correlation had to be proven for this newly developed system, and this was achieved with the use of a 40-arm caliper over the newly reperforated interval. Results showed that the guns had been fired exactly on depth. With three 40 ft [12 m] perforating runs capable of being shot in depths greater than 10,000 ft [3048 m] in less than 12 hours, the system proved to be extremely efficient.