Integrated interpretation: Using reflection seismic and microseismic to de-risk the Duvernay

Ronald M. Weir, Donald C. Lawton, Laurence R. Lines

Development of a resource play such as the Duvernay Formation is subject to intrinsic risks. These may include the risk of incurring additional costs due to an induced seismic event, or risks associated with unexpected thermal maturity, which can determine the value of the processed hydrocarbons (dry gas vs. condensate). These two risks may be related, as the presence of basement faulting may influence the heat flow from the basement, causing local variations in thermal maturity. The presence of basement faulting may also increase the risk associated with induced seismicity, whereby pre-existing faults are reactivated during the course of well treatment. Interpretation is complicated by the variable depositional environment for the Duvernay marine shale; an off-reef depositional system includes mechanisms such as contourite deposition, turbidity/mass flow, and in-situ biological carbonate precipitation, thereby creating variances in total organic hydrocarbon content. Transtensional faulting caused by deep seated strike-slip faults may be reactivated during a completion program, rather than induced hydraulic fractures. Combining the microseismic and reflection data and displaying the data in depth allows the joint interpretation of reflection seismic and microseismic data. A geological picture is constructed by visualizing microseismic hypocenters in a chair plot with reflection surfaces and depth slices. These can be used to determine best practices for the future location and design of horizontal treatment wells.