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Churchill Drilling Tools helps operators improve hole cleaning

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Oilfield Technology,

Churchill Drilling Tools is partnering with operators to significantly improve hole cleaning and project performance by using its Dart Activated Valve (DAV) MX™ CircSub.

The DAV MX was put to the test recently by a European operator in a challenging onshore geothermal well in the Netherlands.

Optimal hole cleaning was essential given the challenging multi-tapered casing profile of the string. By deploying two DAV MX CircSubs, the operator boosted annular velocity and optimised its hole cleaning process across two separate runs. It cut the time to transport cuttings to the surface by around 50% if using a single CircSub, and 75% if no CircSub was in the string. In optimising the hole cleaning process the operator also prevented any concern of managing a stuck pipe situation.

During the first 6 inch section drillout run the operator activated the lower DAV MX, positioned in the BHA, providing an annular velocity boost and flushed cuttings to above the 9 5/8 inch x 7 inch liner. The client then activated the upper DAV MX, placed higher up the drill string, to lift the cuttings to surface before cycling back to its closed position. The same sequence was carried out during the subsequent 6 inch x 8 ½ inch hole enlargement run using another two CircSubs. In total, four DAV MX CircSubs were successfully activated across the two runs.

The client said it was pleased with the DAV MX’s performance and observed a significant increase in cuttings returns after each activation.

The operator also used the lower placed CircSub’s lock open feature on each run for dry tripping, achieving safer rig floor conditions and cutting tripping out time.

As always, the operator had a big safety margin because of the DAV MX’s Emergency Shut-Off Dart (ESD), a fail-safe feature used on the rare occasions an operator has to push beyond the performance envelope and the valve becomes damaged. It was not deployed, but knowing the ESD could seal any leak paths, maintain thru-bore and allow the programme to continue without pulling out of hole, gave the operator additional confidence to complete an ambitious by-pass strategy.

Churchill’s European Regional Account Manager, Corin Lewsey, said: “We’re pleased our DAV MX CircSub continues to help operators drill faster, more efficiently and at low risk.

“In this case, the operator demonstrated that running two CircSubs in the string can be a more reliable and effective method of hole cleaning and saves significant rig time. In 2018 we expect to see this trend increase significantly, especially among the many operators across the globe who are already running one DAV MX and benefiting from the tool’s simplicity, speed and reliability.”

In 2017 operators carried out more campaigns running the DAV MX than ever before. Churchill is also seeing more of its CircSubs deployed in geothermal wells. Last year, the DAV MX was successfully deployed in the world’s deepest and hottest borehole, in Iceland, at a depth of 4659 m and 427º.

Corin continued: “Geothermal wells are an area of expansion for us and reflects the DAV MX’s ability to withstand even the most challenging of environments. There is no other tool available that can match the resilience of our CircSub.”

He added: “More and more operators are benefiting from the value our DAV MX CircSub delivers across a wide range of applications and especially when deployed on a pre-planned basis. The growing demand confirms the quality of our tool, our customer performance and the trust and confidence the industry has in our products.”

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