A dual-porosity model for evaluating petroleum resource potential in unconventional tight-shale plays with application to Utica Shale, Quebec (Canada)

Abstract

Unconventional tight to shale reservoirs vary from tight sandstone/siltstone to organic-rich mudstone/shale, commonly with mixed lithologies. In such reservoir systems, matrix pores and organic pores with different origins and distinct physical and chemical properties co-exist for hydrocarbon storage. Traditional resource assessment methods, designed for conventional reservoirs, cannot handle the two pore systems properly. This study proposes a dual-porosity model to respond to the need for a new method in assessing hydrocarbon resource potential in such reservoir systems. The dual-porosity model treats the two types of pores separately and derives the resource estimates from different sources of data, thus better characterizing unconventional reservoirs with complicated pore systems. The new method also has the flexibility of assessing resource potential for the entire spectrum of mixed lithologies ranging from a complete tight to a pure source rock (organic-rich shale/mudstone) reservoir. The proposed method is illustrated through the assessment of the in-place petroleum resource potential in the Upper Ordovician Utica Shale of southern Quebec, Canada. The results of the application suggest that the proposed approach effectively handles the two pore systems in tight-shale reservoirs effectively and provides a useful tool for estimating resource potential in unconventional plays.

Petrographic Characterization and Maceral Controls on Porosity in Overmature Marine Shales: Examples from Ordovician-Silurian Shales in China and the U.S.

“…Ordos shale belongs to transitional shale. The sample TRA-10 is an example of Early Silurian Utica shale from Appalachian Basin in the U.S. Utica shale is one of the most important gas-producing formations in North America [43,53,[71][72][73]. A sample from Xiuwu Basin is characterized as an overmature marine shale deposit at the Ordovician time period [74].…”

Shale Oil Potential and Mobility of Low-Maturity Lacustrine Shales: Implications from NMR Analysis in the Bohai Bay Basin

“…As indicated in Table , the bulk porosities of the MES shales range from 4.29 to 7.41% with an average of 5.61%. The oil saturation ranges from 9.35–36.09%, with a mean of 15.59%, which is higher than that in the Dongying Sag with an oil saturation of 1–8% . The pores could be divided into micropores (<2 nm), mesopores (2–50 nm), and macropores (>50 nm) .…”

Development of Shale Gas Prediction Models for Long-Term Production and Economics Based on Early Production Data in Barnett Reservoir

“…The CMG's GEM simulator [26] was employed to simulate the base reservoir simulation case (reservoir depth = 2057.40 m, reservoir pressure = 22,063 kpa, reservoir temperature = 96.11 • C, matrix porosity = 0.05, matrix permeability = 0.00023 md, and initial gas saturation = 0.7). The amount of (monolayer) gas adsorbed in organic-rich shales was defined by the Langmuir equation [27], and has recently been applied in other shale gas researches [28][29][30]. Langmuir isotherm data for the Barnett shale are Langmuir volume of 3.54 scm/ton, Langmuir pressure of 8618 kpa, and rock density of 2.50 g/cm 3 [23][24][25].…”