The Effect of Reservoir Characteristics on Productivity and Production Forecasting of Montney Shale Gas in Canada
The productivity of shale gas is closely related to the various reservoir parameters and it is very important to understand the characteristics of the shale reservoir for evaluating its production potential. In this paper, the effect of reservoir characteristics on productivity is quantified and its characteristics is used to forecast the shale gas production for the Montney formation in the Alberta, Western Canada. The shale gas reservoir characteristics can be divided into the reservoir quality(RQ), which is the ability of gas to be stored and the completion quality(CQ), which is the ability to produce the gas out. The productivity of shale gas can be defined as the peak monthly rate(PMR), initial decline rate(Di), and decline exponent(b) based on the various variables in the Arps’ decline equation. The correlation analysis between decline variables and reservoir parameters is conducted to investigate the effect of reservoir characteristics on the productivity of shale gas for the different shale gas flow regimes. The decline trend of the production wells is analyzed using the normalized monthly production rate and divided the flow regimes into the transient linear flow(TLF) and the boundary dominated flow(BDF). The TLF is usually seen for a long time due to the low permeability of the shale reservoir after the shale gas starts production. The hyperbolic equation is fitted for TLF regimes and then the exponential equations is used for the BDF regimes. As a result, the brittleness index is qualitatively correlated with Di and b which are affecting the overall decline pattern. Also, among the RQ parameters, the total organic carbon(TOC) affects the peak monthly rate(PMR) and the amount of organic carbon S1, which is already generated as a hydrocarbon, is highly correlated with Di and b in the TLF regime. Therefore, the shale gas production curve in the TLF regime may be forecasted through quantifying the effect of the organic content on the shale gas productivity. The production forecasting based on the reservoir characteristics especially like a source rock evaluation is very important to define a sweet spot and to evaluate the production potential in the early field development stage. The results from this study can be applied to the various shale reservoir with more accurate economic evaluation by reducing the uncertainty of shale gas potential assessment in advance.
AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018