Diagnosing and resolving unknown well obstructions at high deviations presents significant challenges to Operators. Combining a downhole camera with an electric line (e-line) tractor enables operators to traverse high angles and view the camera feed in real time, options unavailable on conventional Coiled Tubing (CT) unless running expensive smart CT. Furthermore, with e-line already on site, the operator maintains the flexibility to rig up an e-line milling tool to mill the obstruction. This paper describes how e-line tools helped identify the obstruction in a shut-in well and successfully milled the EGF ceramic flapper for the first time.
Earlier this year, in a gas field offshore East Malaysia, an Operator needed to investigate probable sand intrusion from an open-hole gravel pack prior to design a remedial plan to reactivate the well. The well presented several challenges, such as high angles, unknown restrictions, restrictions within the inner diameter (ID), potential sand production, and uncertain flapper valves condition in the well. The Operator opted for an e-line tractor to convey a downhole camera to identify the obstructions and an e-line milling tool as a contingency to mill obstructions or faulty valves.
This operation was completed in six runs and comprised of the e-line tractor conveying the downhole camera for drifting or visually inspecting the completion until successfully logging down to the targeted intervals. During the first two runs, the tractor conveyed the camera through the lateral and found a fluid-loss control EGF flapper partially open but could not pass through because of the restricted ID. In the third run, the tractor worked on the string and tagged the flapper, attempting to close it. The next camera run showed in real time that the flapper valve had been closed. The milling tool was then run in hole (RIH) to mill the flapper on the fourth run. On the fifth run, the tractor and camera confirmed that the valve had been milled successfully and the toolstring could pass through the ID. Finally, the tractor conveyed the logging tool to the target intervals and pulled out with no overpull observed. Running this operation entirely on e-line enabled the Operator to access the well obstructions despite the high angles, view the camera feed in real time, and mill the EGF ceramic flapper valve.
This case shows the effectiveness of e-line operations to succeed in challenging well environments without the cost, risk, or time needed for traditional methods like CT or rigging units. The e-line tractor conveyed the camera at high angles to successfully identify the obstruction, and the e-line milling tool milled the EGF ceramic flapper to restore access to the horizontal section. The Operator completed the logging job, which was essential for future well rectification plans that also included setting plugs for zonal isolation.
