API TR 10TR3-1999 (R2005)

Temperature is the single most important variable affecting cement hydration [1]. Therefore, accurate information about temperatures in a well is critical to cementing operations.Many variables affect wellbore temperature, and measurement of temperature during an actual cementing operation is difficult. However, since the early 1940s temperature data has been gathered, analyzed and converted into estimates of well-bore temperatures with depth. These estimates of temperatureversus depth have been incorporated into American Petro-leum Institute (API) guides for testing cement formulationssince the late 1940s. The API well-simulation test scheduleshave been valuable tools for the petroleum industry as guidesfor testing cement formulations in the laboratory and as esti-mations of wellbore temperatures for cementing operations.Work performed by the 1984Ð91 API Task Group onCementing Temperature Schedules to update the tempera-tures in API well-simulation test schedules is summarized in this report. The Task Group reviewed the largest set of temperature data available to the industry to date. Changes wereproposed to temperatures in the well-simulation test sched-ules in API SpeciÞcation 10, 5th, Edition, based upon reviewof the data.

This report documents:

a. The proposed changes for temperatures.

b. The process used to develop the proposed changes.

c. The process used to develop temperatures in API Specifi-cation(Spec) 10, 5th Edition well-simulation test schedules.

d. The comparison of temperature data sets used to developthe proposed changes to temperatures in API Spec 10, 5thEdition, well-simulation test schedules. Additionally, this report compiles most of the temperaturedata collected by the industry to date into a single documentthat may serve others involved in similar efforts in the future.