Problem
A Qatari operator found themselves in a stuck pipe situation while conducting drilling operations. The client became stuck with their drilling BHA in the 8.5" section at 20,400ft MD and 86 deg INC.
After several days of trying to get unstuck through jarring, changing mud weights, flowrates and acidising the formation, the client made the decision to sever the string with Coretrax HyPR HoleSaver tool.
Using a wireline system would have been extremely time consuming, costly and would have meant using a tractor system to get the explosives to depth. The HyPR performed the cut in less than 6 hours, using no explosives, specialized personnel or wireline, just a dart and circulation.
Solution and Achievement
An NC50 Coretrax HyPR HoleSaver was included in 8.5" drilling BHA as a contingency whilst drilling the section due to the risk of a stuck pipe scenario. Directly below the HyPR there was a 4 ported NC50 DAV MX CircSub to isolate the lower BHA should the need arise to spot coarse LCM and assist with high rate hole cleaning. The DAV allowed circulation after the BHA became stuck. Further down the BHA, a single Coretrax Float Sub, flapper type, non-ported was positioned as protection against the gas bearing well.
The HyPR 46A Fishing Dart, was dropped at 2:40am after a short call with the Coretrax support team to discuss hydraulics and mud properties. The dart was dropped into the drill string and pumped down at 300 then 350gpm for 45 minutes, the increase was decided based on experience from offset wells and based on the trajectory. The dart successfully landed and a positive pressure indication was seen at surface. The pressure drop through the dart was expected based on the hydraulic calculations. Throughout the HyPR cut the flow rate range was from 520 to 550gpm using a 11.3ppg WBM.
The hydraulic cut took just under 6 hours to completely sever the pipe connection at the required point. During the cut, two 1.3T bags of Coretrax HyPR sand was added and torque & tension was added to accelerate the HyPR Cut.
The operator was delighted with the result and thankful that they did not need to mobilize a wireline crew or handle explosives.
