Properties of Oil sands and Bitumen in Athabasca

Summary SAGD(Steam Assisted Gravity Drainage) is one of the most effective methods to produce bitumen (Fig.1). For seismic monitoring of the steam front and its effect on the formation, it is important to know correctly the properties of oil sands and bitumen. We measured the Pand S-wave velocities of oil sands and bitumen from Athabasca, Alberta, by ultrasonic measurement system, and valuated the seismic velocities dependence on temperature and effective pressure. Velocity variation measured from ultrasonic measurements is encouraging for the seismic steam monitoring and they provide clues for quantitative evaluation of steam development during SAGD operation. Introduction Figure.1 the concept of SAGD. SAGD is the methods to produce bitumen by reducing oil viscosity so they flow themselves. To Monitor the location of the steam front is very important to operate SAGD. In time-lapse seismic analysis, amplitude change caused by decrease in velocity and density is widely used to estimate the location of the steam front. The decrease depends on temperature and differential pressure (i.e., the difference between confining and pore pressures). The effects of steam flooding on the reservoir temperature and pressure conditions are shown schematically in Fig.2. Following 5 different cases in reservoir conditions are characterized by temperature, differential pressure and saturation.