By Dev George, Houston
Elmar Services Ltd has introduced a new proprietary design of wireline BOP ram for the global market, the Q-Guide, which is said to be capable of shutting off well pressure by reliably guiding and sealing wireline typically entering the BOP at a non-parallel angle. Elmar says the new design is also capable of employing its new Multiline Inner Seal to allow switching between slickline, electric-line, and fishing operations without having to change rams. Suited to use in any wireline BOP, the Q-Guide and Multiline Inner Seal are claimed to offer significant cost and reliability benefits over more traditional products.
Shutting off well pressure is essential should wireline damage or problems in maintaining a seal at the grease head occur. During the closing stroke, the rams must guide the wireline into a semi-circular groove in the ram body and create a fluid tight seal without damaging the cable.
However, recent reports have pointed to difficulties encountered in traditional ram designs when wireline enters at certain angles to the axis of the BOP bore which can often occur in deviated wells. If the rams close before the wireline is positioned in the line groove, the cable can be trapped and damaged, thus reducing the safety and integrity of the operation. This problem has occurred in the field and has been confirmed in trials conducted by Elmar, which says it is found to be more likely to happen with large bore BOPs, four inches in diameter and larger.
As a result, Elmar sats it developed the Q-Guide ram that on closure provides a positive alignment for the wireline. Special guides on either side of the inner seal restrict the wireline so that the section of line contacting the seal is always centered and parallel to the BOP axis. These rams will be supplied as standard for all future Elmar wireline BOP orders.
Elmar's new Multiline Inner Seals can be used with the Q-Guide to create a universal 'multiline' ram. Although the line groove in the inner seal is sized for 5/16" line, the seal is able to seal around any line from 0.092" OD (Outside Diameter) to 0.312" (5/16") OD.
To date, the Q-Guide is said to have demonstrated excellent reliability in field trials conducted by Elmar at the end of 2000. Similarly, the Multiline Seal has already been used with success in the North Sea, Gulf of Mexico, and Asia Pacific, for a number of major service companies.