Injection-induced Microseismicity in Colorado Shales

Abstract

Imperial Oil Resources Limited uses cyclic steam stimulation to recover oil from their Cold Lake oil field in Alberta. This operation, in particular situations, can be associated with the failure of well casings in the Colorado shales above the oil-bearing formation. A number of fluid injection operations was undertaken at this site and the associated microseismicity was detected using two three-component geophones and fifteen hydrophones. The purpose of this experiment was to simulate the occurrence of a casing failure, determine the feasibility of monitoring in a shallow environment, and characterize the microseismic activity. A calibration survey provided values of 1786 9 108 m/s for P-wave velocity, 643 9 56 m/s for S-wave velocity and 0.428 9 0.017 for Poisson's ratio in the shale formation. Estimates of the quality factor Q P were 15 for the horizontal direction and 38 for the vertical direction, corroborating the evidence of velocity anisotropy. Calibration shots were located to within 10 m of the actual shot points using triangulation and polarization techniques. Several hundred microseismic events were recorded and 135 events were located. The results showed that microseismic activity was confined to depths within 10 meters of the injection depth. The experiment clearly established the feasibility of detecting microseismicity induced by fluid injection rates typical of casing failures in shales at distances over 100 m.

An Overview of New Developments in Shale Gas: Induced Seismicity Aspect

“…As another application of induced seismicity monitoring in the oil and gas industry, wellbore integrity in shale gas development can be considered as an outcome of using that technology as it has been long used for Cyclic Steam Stimulation (CCS) projects to observe, detect, and locate casing failure or slip due to steam injection in thermal oil recovery operations [53][54][55].…”

2 Carbon Dioxide Capture and Storage

“…Fluid injection into boreholes can induce microseismic activity, as for example at the Rangely Oil Field in Colorado, USA (Gibbs et al, 1973;Raleigh et al, 1976), in test sites such as the drillholes of the German continental deep drilling programme (Shapiro et al, 1997;Zoback and Harjes, 1997) or the Cold Lake Oil Field, Alberta, Canada (Talebi et al, 1998). Deep-well injection of waste fluids may induce earthquakes with moderate local magnitudes (M L ), as suggested for the 1967 Denver earthquakes (M L of 5.3; Healy et al, 1968;Wyss and Molnar, 1972) and the 1986-1987 Ohio earthquakes (M L of 4.9; Ahmad and Smith, 1988) in the United States.…”

“…Deep-well injection of waste fluids may induce earthquakes with moderate local magnitudes (M L ), as suggested for the 1967 Denver earthquakes (M L of 5.3; Healy et al, 1968;Wyss and Molnar, 1972) and the 1986-1987 Ohio earthquakes (M L of 4.9; Ahmad and Smith, 1988) in the United States. Seismicity induced by fluid injection is usually assumed to result from increased pore-fluid pressure in the hypocentral region of the seismic event (e.g., Healy et al, 1968;Talebi et al, 1998).…”

Analysis of microearthquake data at Cold Lake and its applications to reservoir monitoring

“…The CSS process produces microearthquakes or microseismic events ͑henceforth referred to as events͒ in the overburden and possibly in the reservoir as well. Boone ͑1998͒ andTalebi et al ͑1998a;1998b;1998c͒ studied the seismicity and casing failure in the production wells at Cold Lake, and theoretically analyzed the possible failure mechanisms. More recently, McGillivray ͑2005͒ used induced microearthquake data to monitor steam-front diffusion in the Peace River deposit.…”