This study compares the performance of openhole packer to cemented liner completion systems across 30 single-lateral horizontal wells by one operator in the northern Montney gas resource play. With up to 5,400 Tcf of initial gas in place, the Montney Formation rivals the Marcellus play both in size and scope of future development. Our data demonstrates that the benefits of openhole completions relative to cemented liner completions include an average 25% increase in IP30 rates, an average increase from 7 to 10 Bcf in expected ultimate raw gas recovery per well, an average 13% decrease in stimulation period costs, plus an average 36% decrease in stimulation operating time (days), all on an unadjusted basis. When adjusted for total proppant placed or total fluid pumped on average per completion, the relative benefit of openhole systems ranges from 6% to 31% depending on the test metric selected.
Surface-array microseismic monitoring was conducted over two of the study wells, one involving a cemented liner system and one involving an openhole system, with the goal of understanding the stimulation patterns relating to each completion style. Focal mechanism solutions were calculated for individual microseismic events and displayed on a series of failure plane crossplots segmented by lateral distance from the stimulation stage mid-point. Our evaluation focuses on event counts and magnitudes, plus event clustering relating to failure style. This paper presents the first published case study to apply this new method of hydraulic fracturing analysis.
The openhole stimulation in our study area is characterized by a large event population, exhibiting a moderate cluster of high-angle failure initiating in the near-well region. Event clustering strengthens as lateral distance from the wellbore increases. The cemented liner stimulation is characterized by fewer events which exhibit weak clustering at moderate angles of failure across all distances, but particularly in the critical near-well region. Together with the observed magnitude histograms, these patterns clearly indicate different styles of rock stimulation. We infer that the openhole completion benefited from constructive interference during fracturing due to direct pumping access to multiple random initiation points afforded by the open annulus. In contrast, the cemented liner completion fails to develop a comparable complexity because the limited entry perforation spacing restricts constructive interference during the stimulation process.
Debate continues regarding the advantages of openhole vs. cemented liner completions. This paper presents an example of another technique to evaluate and compare stimulation patterns during hydraulic fracturing. The results from this study support the continued application of openhole completion systems to the Montney play in northeastern British Columbia.