A Renewed Focused on Cementing Design Has Improved the Cement Bond Log in Shorter Time Wait on Cement Time

Abstract

AbstractChallenging Low Oil Prices environment and LEAN maturity in PDO provided the impetus to boost performance and optimize cost. PDO has identified Waiting On Cement (WOC) before performing cement quality logs and Perforation as one of the major cost contributor and hence, an area of focus. Extensive laboratory works on cement slurry designs were carried out and ended by identifying a fit for purpose cement design reducing the WOC time by 50%.Relatively low bottom hole temperatures (BHT) made the design of high and fast developed compressive strength (CS) cement for shallow wells more difficult as cement CS development at this range of temperature is slow. After extensive laboratory testing on different slurry designs, PDO team, along with cementing service companies managed to design a fit for purpose cement slurry, which does not only develop enough CS in a very short time but reduces WOC by 50%.The systematic approach in designing the cement slurry and technical input helped to achieve the outstanding results. The field trials and extensive Cement quality evaluation using CBL/VDL USIT logs have also demonstrated an excellent cement adherence to casing which is even better than the quality of conventional slurries. Four CBL/VDL USIT logs were run out of seven wells after 20 hours WOC to evaluate the cement quality behind the production casing and the results were excellent. Three out of seven wells were perforated within the required 20 hours WOC frame with no well integrity issue nor impairment on the quality of the produced fluid.This paper explains the design approach and shows how earlier CS can be achieved at low BHT and with excellent cement bond evaluation. This improvement in cement design enabled to cancel scrapping operations, saving time and money, reducing the risk exposure, and achieving faster well delivery.