Saudi Aramco's Unique Cement Tester Gets Patent

A device that could measure the expansion or contraction of cement would have a concrete payoff for Saudi Aramco. Science specialist Scott S. Jennings of EXPEC Advanced Research Center designed just such a device - the Cement Shrinkage and Expansion Tester - as a way to measure those effects.

It is so unique that it was patented by the company and adopted by oil majors around the globe.

A standard mix of Class G cement shrinks 2 percent after it sets. In wells where high pressure is a concern, expansion additives are used to reduce shrinkage during setting.

The new device enables engineers to evaluate shrinkage or expansion as materials are heated to temperatures simulating well conditions.

Under U.S. Patent 7,240,545 titled "Test Apparatus for Direct Measurement of Expansion and Shrinkage of Oil Well Cements," Jennings created an instrument to approve or reject certain cements for use in oil and gas wells.

Jennings' Cement Shrinkage and Expansion Tester is designed to fit into existing ultrasonic cement analyzer cells. Cement slurry is poured into the cell and separated by a rubber diaphragm. Water serves as a cushion between a floating piston and the diaphragm. Piston movement indicates shrinkage or expansion.

The instrument allows the company to ensure that selected materials are up to the task, saving money on costly repairs or shutdowns and promoting safer operations.