Abstract

In the pursuit to access reserves at ever increasing departures the ability to successfully run very long casing strings in highly deviated wells is essential. Running 6200 ft. (1890 m.) long 7″ liner in a highly deviated ‘S’ shape well (80 Deg.) with high dogleg severity 15 Deg. /100 ft. across whipstock window) is considered a big challenge. The severity of this challenge increases multifold while passing the string through challenging interbedded formations.

The case presented here had unique achievement that last seven days while performing extensive open-hole logging after drilling 8-½″ section and prior running the liner hanger system. Aligned with the pre-determined challenges; the normal drilling practice is performing two wiper trips. First wiper trip after drilling the 8-½″ section, pulling out till the 9–5/8″ window at 8740 ft. and RIH again till 8-½″ TD at 14442 ft., the first wiper trip would have consumed +/- 24 hours rig time. Then follow with another wiper trip through running 8-½″ drilling BHA from surface till TD at 14442 ft. after pulling out of hole with the logging tools, the second wiper trip would have consumed +/- 36 hours. Accordingly, a total of +/- 60 hours rig time would have been consumed in both wiper trips. Wiper trips would have increase the gap between finalizing drilling 8-½″ hole and running liner hanger system. Increasing the gap would thereby increased the possibility of open-hole pack-off while running the liner hanger system. Accordingly, an optimum solution is to run Free Rotating Eccentric Guide Shoe (FREG) with two Sure Seal valves each provided a 3.14 square inch (20.3 CM2) minimum flow area to allow large cuttings and debris to pass through. In addition, any resulting side force during running would rotates the guide shoe away from the obstruction, thus allowing continued running of the pipe to the predetermined depth without rotation of the entire casing or liner string and reducing the risk of string stuck. Accordingly, the risk of pulling out of hole twice and performing two wiper trips was eliminated.

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