Towards improved hydraulic fracturing effectiveness through modelling and data integration: A case study from the Horn River Basin, BC
Date
2018-03-28
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Abstract
Understanding how hydraulic fracture (HF) treatments affect a formation is crucial to ensure economical production in unconventional reservoirs. This thesis investigates an industry dataset from the Horn River Basin (HRB) that consists of microseismic (MS), reflection seismic, drilling, and completion data. Analysis of the MS reveals high variability in event clouds. While single monitor well bias is prominent in the magnitude statistics trends, kinked probability distributions and high outlier events suggest multiple mechanisms for MS generation. Spatial distributions are not classical bi-wing patterns but show lateral confinement, azimuthal variations, and out-of-zone growth. Stress heterogeneity is evident from variability in the instantaneous shut-in pressure (ISIP) and breakdown pressure values. The reflection seismic attributes of amplitude, most positive curvature (kpos), P-Wave impedance (Zp), and brittleness (BRI) show reservoir compartmentalization and are interpreted to account for irregular microseismic event growth. Deep MS growth is attributed to cross-cutting linear kpos trends and high values also appear to create a barrier; MS events arrest or curl to avoid positive anomalies. Rapid Zp transitions are also interpreted as a barrier and perforations in high zones correlate to rounded cloud growth and completion issues. In some situations, the high kpos and Zp values are co-located, suggesting that the impedance contrast is due to fractures. Both wells are in brittle areas but BRI does not appear to dictate growth direction. A completion method, named here as Short Interval Re-injection (SIR), is investigated with respect to the cohesionless state of the created fracture network, comprised of natural fractures (DFN) and the HF plane. The computer modelling code 3DEC was used to create a geomechanical model with observed MS events used as the calibration metric. The increase in MS event count seen in literature was replicated in the observed and modelled MS but it was discerned that the technique did not increase fracture complexity, as few new fractures were created during the re-injection. It is instead suggested that the SIR technique reinforces previously created fractures to improve stage production.
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hydraulic fracture, Microseismic, reflection seismic attributes, Short Interval Re-injection, natural fractures (DFN), geomechanical model, Horn River Basin, data integration
Citation
Kent, A. H. (2018). Towards improved hydraulic fracturing effectiveness through modelling and data integration: A case study from the Horn River Basin, BC (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/31766