The world contains a vast store of energy in fluids that scientists believe could provide the world with transportation fuels for a century or more. Operators are using new thermal stimulation techniques to unlock this potential from heavy oil, tar sands, bitumen, and oil shale. The efficiency of these programs, however, requires that engineers who are usually well versed in the properties of reservoir fluids also consider thermal properties of reservoir rocks.
Today about 60% of world oil production attributed to enhanced oil recovery (EOR) methods comes from thermal stimulation methods, such as injected steam or hot water, which have been practiced for more than half a century. In the Kern River oil field in California, USA, where production had stagnated for decades, steam injection increased production more than tenfold.
In wells in the Yarega oil field in the Komi Republic, Russia, production per zone increased from about 4% per zone average recovery using conventional wells to 33% and, in some cases, nearly 70% per zone from wells using thermal mining techniques.
An article in the Autumn 2012 issue of Oilfield Review examines this critical facet of thermal EOR program design with a review of the basic thermal properties of rocks. It looks at their measurement using conventional, often time-consuming, techniques.
The article also introduces a new measurement technique that uses optical sensors to rapidly quantify thermal properties of rock. The technique has been used on thousands of rock samples gathered from deep scientific boreholes around the world and, more recently, it has been used in sandstones, shales, and carbonates from petroleum reservoirs.
Also highlighted is research on cores from Russian oil fields which has revealed surprising variability in reservoir thermal properties. Reservoir simulations demonstrate the importance of this variability in predicting EOR outcomes and the impact such understanding can have on project economics.
Read the full article at the Oilfield Review Web site.
Chekhonin E, Parshin A, Pissarenko D, Popov Y, Romushkevich R, Safonov S, Spasennykh M, Chertenkov MV and Stenin VP: “When Rocks Get Hot: Thermal Properties of Reservoir Rocks,” Oilfield Review 24, no. 3 (Autumn 2012): 20–37.