Experimantal Investigation of Properties of Oil Well Cement

Abstract

Accidental gas migration is a problem all drilling engineers are trying to avoid. Good cementing practice between the casing and the wellbore is one of the preventive actions. Shrinkage may lead to insufficient protection against gas migration. This paper has tested various of parameters such as external shrinkage, compressive strength, flexural strength, density and free fluid. The parameters mentioned correlates with good protection against gas migration. Shrinkage and compressive strength was tested over a period of 24 hours. Free fluid was measured after 2 hours of curing. The density was measured immediately after the cement and water had been mixed.All tests were conducted at atmospheric pressure. The method used to measure the shrinkage consisted of a cement-filled condom immersed in a water bath at a temperature of 21 degrees. This experiment was conducted with 6 samples. Three different forms were used to mould specimens for pressure testing. Standardized the testing of compressive strength were used. Twenty-four samples with prism form twelve samples with cubical shape and six samples of cylindrical shape were tested. Concrete specimens were cured at two different temperatures. Half of the samples were cured at 38 degrees, and the other half at 60 degrees The prism-shaped samples were used for testing the bending strength. The experiments were time consuming and rendered during 6 weeks. -Results showed that the outer shrinkage of cement samples were high compared with other measurements performed by the industry. The performance of these tests deviated from normal procedure which affected the result. -Strength testing showed that the cement samples developed enough strength compared to other published work. Anyway, most of the published testing is performed with other conditions, making it difficult to compare. -Density measurements showed a close predicted value. -Test performed to determine the secreted fluid, did not exceed the minimum requirement set by API(2009).