Abstract
A three part process has been developed to generate a correlation which can be used to 1) map representative ∅h in the Kakwa Cadotte reservoir and 2) optimize the design of hydraulic fracture treatments. This same process can be applied to multi-fractured horizontal wells, completed in the Upper Montney reservoir, to generate a relationship between Estimated Ultimate Recovery (EUR), ∅h and total hydraulic fracture tonnage.
The initial stage of the process required the application of IDC (Inverted Decline Curve) technology to determine independent quantities of 1) reservoir quality (kh) and 2) hydraulic fracture placement (as measured by fracture half length = Xf). Using this IDC technique to differentiate between the better and lesser quality wells we can find a correlation between Estimated Ultimate Recovery (EUR) and some function of porosity, net pay and fracture tonnage (the second step in this process).
The physics behind this relationship essentially correlates to hydraulic fracture volumetrics and effective insitu permeability within each well’s drainage area. Wells that do not match the trend established by the "clear majority" of wells (data points) can now be readily flagged and included in the established correlation by modifying ∅h and/or frac tonnage until they match the trend. This adjustment would of course have to be rationalized by either a change in 1) possible kh, throughout the well drainage area, or 2) the effective frac tonnage displaced for the well. Given that most of the two dozen wells evaluated established an excellent correlation, this technique became very useful in narrowing the range of possible kh or effective Xf, within each well’s drainage area. After establishing the relative contribution to EUR of 1) reservoir quality and 2) hydraulic fracture effectiveness, we could map a representative kh distribution to optimize future well locations.
Finally, the process (for developing this correlation) was also tested on 46 Upper Montney horizontal wells producing from the Swan reservoir. Although producing into multiple hydraulic fractures, the linear trend of the inverted decline curve, for these wells, still yields a reliable indicator of permeability and/or fracture placement effectiveness. An excellent correlation exists between IDC slopes and independently determined EURs but more work is required to differentiate between the relative contributions of reservoir quality (kh) and hydraulic fracture effectiveness (Xf). This reservoir surveillance technique will be useful for the placement of horizontal wells, particularly unconventional Montney wells, and the optimization of hydraulic fracture treatments, along the entire Montney trend.
