| Abstract | The oil well cementing is a procedure to pump special cement from surface
down to the oil well filling the space between casing and formation to seal off the
formation. Therefore, well cement’s properties are very important in ensuring the
borehole stability and a study on these properties change with temperature and
pressure in oil and gas reservoir is always much needed. To achieve good zonal
isolation one needs to know the characteristics of oil well such as well depth, well
temperature and pressure. The slurry should be tested and characterized for relevant
parameters. In this study, three types of oil well cement were tested, i.e., low, medium
and high density. An amount of 23 resistivity tests, 3 pore water conductivity tests
were done. In addition, the Ultrasonic Cement Analyzer (UCA) tests were conducted
by BJ Services laboratory. To simulate as close as possible to the borehole conditions,
two main types of testing conditions were carried out, and namely, resistivity tests
under only high temperature conditions and resistivity tests under both high
temperature and pressure conditions. The correlations between resistivity, thickening
time, compressive strength and porosity of oil well cements were found from this
study. The results of the study showed that resistivity tests, if successfully designed
and set up for high temperature and pressure conditions can be a valuable to assist the
traditional Ultrasonic Cement Analyzer (UCA) tests in assessment of the oil well
cement slurry. |