Results from a long-term field study to improve zonal isolation show that rotating production casing inunconventional well laterals is possible and that it delivers excellent cement quality.This paper reports theresults of the study.To date,44 production strings have been rotated during cement jobs.Specific details covered are cement bond evaluation results,methods used for modeling casing running,torque and drag forces for floated and rotated strings,torque estimation for casing connection selection,operational procedures,mud conversion cement additive,and best practices.Evaluation of cement bondis based on ultrasonic cement logs acquired in casing strings cemented with and without casing rotation.Advanced azimuthal ultrasonic logs were used to measure cement placement and quality.Trials with a mudconversion cement additive evaluated whether the cement quality could be achieved with additives insteadof rotation.Both 61/4 in.and 81/2 in.hole sizes in 10,000 ft lateral lengths were evaluated.Prior studies demonstrated that casing movement is crucial for efficient mud removal(Hyatt et al.1984;Gai et al.1996),yet it is not a common practice on long horizontal sections in our company.The casingrotation initiative reported here was enabled by the availability of reliable high torque casing connections.The results shared in this paper demonstrate that it is necessary to rotate casing while cementing horizontalwells with 10,000 ft lateral lengths for effective cement isolation in the annulus.The cement bond resultingfrom rotated cement jobs is near-perfect.Long-term study is needed to evaluate the effect of optimal cementon hydraulic fracturing effectiveness,production,and the long-term health of the well.Results reported include log data and modeled torque and drag values paired with operational data tovalidate the models.Log data is available for eight lateral wellbores evaluated during the base case and trialperiod.It is unique in that log data was acquired for both the base case and trial wells.This paper supports well-known cementing best practices(McLean et al.1967;Zurdo et al.1986;Reiley1987;Wilson et al.1988;Sabins 1990;Torsvoll et al.1991;Kettl 1993;McPherson 2000;Nelson et al.2006;Al-Baiyat et al.2019)with undisputable log data.The operational practices can be applied to manyunconventional operations to implement casing rotating into their cementing programs.The method sharedto estimate torque can be implemented by any drilling engineer with access to torque and drag software,enabling them to choose the right casing connection for their application.
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