Addressing Challenges for Consistent Improvement of Cement Bonds in South Oman Fields

Abstract

Short liner cementing is very common in Oman southern oil fields. Among the challenges one can find no mechanical separation between the fluids, cement and pre-flush volumes are relatively small leading or increasing the chances of contamination and requiring remedial cementing jobs with uncertain success. As a result, poor cement bond log across the liner section were observed in more than 80% of all the cementing jobs. An engineering approach was proposed for this scenario. First increase rheologies of the fluids using physics instead of chemistry to diminish the fluid contamination inside of the casing and create a better sweeping effect outside of the casing. Selecting the adequate solid size ratios of the weighting agent to reduce the possible loss circulation problems generated by higher friction pressure. Increasing the generation and ultimate compressive strength of the cement system and finally providing expansion properties to the set cement. This paper presents the field CBL/USIT logs results and a case study showing the application and effectiveness of the technique proposed comparing with the previous approach in different wells.