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Summary To plan cementing operations in oil wells, predicting accurate circulating temperature is required. Failure to predict the circulating temperature can result in the wrong thickening time. To the best of our knowledge, correlation of the tables in API Recommended Practice 10B are usually chosen to predict bottomhole circulating temperature (BHCT), but both are not suitable in every block with a different geological condition. To design thickening time of the cement slurry, it is necessary to give a credible temperature profile of the wellbore during cementing pumping. Accordingly, a heat transfer numerical model has been developed to simulate conditions encountered down hole. To be accurate, the thermal conductivities and the specific heat of the mud, the spacer, and the cement slurry have been tested. The circulating temperature encountered by the cement slurry rises with the drop of the rate, the increase of the lateral section, the decrease of the slurry density, the decrease of the slurry thermal conductivity, and the decrease of the slurry-specific heat. The simulated data agree with the data obtained from the field case. The heat-up process of the cement slurry in simulation is different from that in the API thickening-time test. To analyze the impact of heat-up process on thickening time, two tests were designed. The results show that the heat-up process has a significant impact on the thickening time. Therefore, the method given by API has some limitations. The wellbore temperature field during cementing pumping was analyzed, and the real-time temperature of fluid was tracked, which supports the cementing design optimization and job safety, also improving bonding quality.
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