| |
EV Offshore Ltd.Downhole camera prevents costly contingencies on Banff Field
Posted: 15 December 2004
EV Offshore Ltd., a leading provider of camera inspection systems, said that it has completed a significant downhole inspection operation in the North Sea for CNR International (UK) Ltd. As CNR prepared to re-open one of its wells for production on Banff field this summer, engineers reviewed the previous end-of-well report. It indicated that metallic debris could be evident on top of the tubing hanger, prohibiting the latching of the tubing hanger running tool for intervention purposes. In addition, it said that the primary sealing area for the tubing hanger running tool could be damaged due to previous cleanout operations. To reinforce its planned contingencies, the engineers had to see what was going on downhole. CNR met with EV Offshore (EVO) in Aberdeen to discuss carrying out a downhole inspection with the CamScan EVO2, a camera inspection system designed to inspect conditions visually downhole and subsea. The inspection would be carried out on Transocean’s rig John Shaw to inspect Well B4, 200kms offshore Aberdeen . EVO would inspect the area above the tubing hanger crown plug and annular cavity. The procedure wasn’t going to be easy, especially in turbid water at depths of 360-feet.
EVO’s initial solution was straightforward: deploy the CamScan EVO2 downhole on drillpipe with the camera running tool (CRT). This approach would offer full, continuous hemispherical viewing - in colour or monochrome - while running downhole. It is also capable of flushing turbid water and dislodging obstructions at target depth to offer a clear view.
Upon further analysis of CNR’s subsea drawings, EVO established there would be a blind spot that the CamScan could not view on its own: the sealing area that would be critical for the primary intervention seal. Fortunately, the CamScan allowed for an auxiliary camera to be controlled from the same topside control unit. A second camera was mounted on the side of the CRT with its control whip lead plugged into the auxiliary port on the rear of the camera. Eccentric nylon sleeves were engineered to mount the side camera to provide guidance into the inspection area. The auxiliary camera would provide a direct vertical view into the annulus. EVO presented its engineered solution. Following further discussion, CNR expressed satisfaction with the proposal, and instructed EVO to proceed. Mobilisation could have been scheduled to take place within just 10 days, so nylon sleeves and auxiliary camera were built, tested and certified. EVO mobilised the equipment by boat on 19th July, with two EVO offshore operators flying out the following day. On July 22nd at 14:45 , EVO prepared to run in-hole by making up the CRT to the drillpipe. Once the CRT was tightened to the required torque, the two nylon sleeves, CamScan rotate-and-tilt camera and auxiliary side camera were fitted. All locking security collars and screws were tightened to prevent items from being lost in-hole, and surfactant was applied to the camera viewing domes to disperse and prevent debris from sticking to them. At 15:30 running in-hole commenced. Immediately beneath the rotary table, as the camera entered 18-inch casing, visibility was less than 10 millimetres due to the turbid water. At 16:05 on the last stand, the top flush assembly was secured to the drillpipe. Thirty minutes later with the flush pump in place and visibility still less than 10 millimetres, seawater flushed the area at five bbls per minute. Within minutes, the internal features of the crown plug became visible. By flushing filtered seawater to displace the turbid water, the debris came into view. CNR engineers surveyed the scene carefully. Armed with an accurate view of the area, CNR engineers moved forward with a strategy to deal with the obstructions, allowing Well B4 to be re-opened as planned.
By 18:00 , EVO had broken out the CRT and cleared the drill floor. The operation took just 3.25 hours, including making up the running tool to the drill-pipe, running in-hole, inspection, pulling out-of-hole and breaking down the running tool. By delivering an effective way to inspect critical sealing areas and identify foreign matter downhole, EV Offshore provided CNR and Transocean with a positive way forward, eliminating costly contingencies. On completion of the inspection run, a CNR subsea engineer commented, “It was imperative that we obtain an accurate visual in order to plan and execute our contingencies with a high degree of confidence. Fortunately, EVO were able to adapt the CamScan with a manoeuvrable auxiliary camera, and provide jetting ports for clear downhole video footage.” Jack McKinley, offshore installation manager for Transocean, said, “EVO provided us with the perfect solution to a complex problem using an impressive piece of technology. We are extremely grateful.” Since introducing its 24-hour call-out service and opening its facility in Aberdeen , requests for “trouble-shooting” and planned inspections have risen significantly. Looking ahead, EVO will carry out a number of inspections in the southern and central North Sea with support from its bases in Aberdeen and Norwich .
Posted by Editor Pipeline Magazine
Information supplied by companies
or PR agencies who are responsible for content. Send press releases
to info@pipelinedubai.com |
|
