Cement integrity preservation during completion, stimulation,rnproduction, and even, during well abandonment is of criticalrnimportance for an operator from long-term economic,rnproductivity, and safety perspectives. Traditionally,rncompressive strengths have been considered indicators ofrncement integrity. However, numerous squeeze cementing jobsrnregularly performed on completed wells are testament to thernpoor correlation between compressive strengths and cementrnintegrity. Additional mechanical properties such as tensile andrnflexural strengths, elastic modulus, and Poisson's ratio arernbeing taken into account with increasing frequency forrnmaximizing the cement sheath performance during the life ofrnthe well. Unfortunately, all such measurements are performedrnon samples that have been cured, either under wellborernconditions (for example, pressure and temperature), orrnlaboratory conditions (for example, atmospheric pressure) butrntested at atmospheric pressure and temperature. Suchrnproperties may at best be useful for comparing differentrnformulations in the selection process but do not providerninformation about the cement properties under downholernconditions.rnUsing ultrasonic shear wave and compression waverncombination measurements, dynamic mechanical properties,rnsuch as elastic modulus, bulk modulus, and Poisson's ratio andrncompressive strength, are measured under pressure andrntemperature. These measurements are compared withrnmechanical properties obtained from load vs. displacementrnunder static conditions and acoustic compression and shearrnwave measurements at atmospheric pressure and temperature.rnCorrelations are made for several slurries. The results arernpresented. The results also will present cases where thernmeasurements made using this method demonstrated uniquernadvantages over the conventional load vs. displacementrntechniques.
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