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石油技術協会誌 第 85 巻 第 1 号 （令和 2 年 1 月）35 ～ 43 頁 Journal of the Japanese Association for Petroleum Technology Vol. 85, No. 1（Jan., 2020）pp. 35～43

講 演 Lecture

Characterizing controls on reservoir properties in unconventional shale and tight reservoirs＊

Levi J. Knapp ＊ ＊ ，† , Shinnosuke Uchida ＊＊ , Takashi Nanjo＊＊ , Tatsuya Hattori＊＊ Omid Haeri-Ardakani ＊＊＊ and Hamed Sanei ＊＊＊ , ‡

（Received August 30, 2019；accepted November 21, 2019）

Abstract： Since 2014 JOGMEC has been collaborating with Natural Resources Canada（ NRCan） along with industry partners in the area of unconventional reservoir characterization and technology development. Based on a June 12 2019 presentation at the JAPT Exploration Technology Symposium in Tokyo, this paper presents research from two major shale and tight unconventional reservoirs, the Upper Devonian Duvernay and Lower Triassic Montney formations in western Canada, and examines the differences between these two fundamentally different types of reservoirs. Solid bitumen strongly in uences reservoir quality in both types of reservoirs but in very different ways. In tight reservoirs（ i.e., Montney Formation） solid bitumen typically occludes pores and pore throats, while in shale reservoirs（ i.e., Duvernay Formation） solid bitumen can be the primary host of porosity.

Keywords： Unconventional, tight reservoir, shale, bitumen, Montney Formation, Duvernay Formation, Canada

rocks themselves, or only contain thin source rock intervals. 1. Introduction The hydrocarbons within tight reservoirs have typically The geological and petrophysical properties of unconventional migrated from overlying, underlying, or intraformational source shale and tight reservoirs are highly variable（ Jarvie, 2012）. The rock intervals（ Wood et al., 2015）. Duvernay Formation shale reservoir and Montney Formation The distinction of these two types of unconventional reservoirs tight siltstone reservoir of western Canada offer an excellent has massive implications for expected reservoir properties such opportunity to compare these two types of unconventional as porosity and permeability, as well as strategies for exploration reservoirs. Shale reservoirs are dominated by clay-sized and production. Since shale reservoirs tend to be self-sourced, particles（＜ 4 µm）, are organic-rich source rocks, and the contain abundant primary organic matter, and reduced inorganic reservoir intervals are self-sourced. In shale reservoirs the fluid matrix porosity due to compaction, organic porosity tends to hydrocarbons（ gas, oil, and viscous bitumen） are generation be a significant fraction of the total porosity（ Loucks et al., products of the primary depositional kerogen within the same 2009; Jarvie, 2012）. This leads to positive correlations between formation. In contrast, tight reservoirs, also known as “hybrid total organic carbon（ TOC） and porosity. In contrast, tight reservoirs”（ Jarvie, 2012）, are typically coarser-grained, reservoirs generally show a negative correlation between dominated by silt and very fine sand, or carbonates, especially TOC and porosity because the solid organic matter present in in producing intervals. Tight reservoirs often are not source the reservoir is generated from migrated oil and occludes the primary inorganic pores and pore throats（ Sanei et al., 2015; Wood et al., 2015, 2018）. Shale reservoirs are typically most porous in intervals with moderate to high TOC, while tight ＊ 令和元年 6 月 12 日，令和元年度石油技術協会春季講演会 地質・探 鉱部門シンポジウム「天然ガス探鉱・開発の現状と課題－低炭素 reservoirs are most porous in intervals of low TOC. 社会に向けて」にて講演 This paper was presented at the 2019 JAPT Petrophysical properties of unconventional shale and tight Geology and Exploration Symposium entitled “Natural Gas Exploration & Development - Current State & Challenges Toward Low Carbon Society” reservoirs are closely associated with organic matter（ e.g. held in Tokyo, Japan, June 12, 2019. Jarvie, 2012; Mastalerz et al., 2013）, and as such it is important ＊＊ 石油天然ガス・金属鉱物資源機構 Japan Oil, Gas and Metals National Corporation（JOGMEC） to define the various organic components present. In source ＊＊＊ カナダ地質調査所 Geological Survey of Canada rocks, kerogen is the primary depositional organic matter ‡ オーフス大学 now at Aarhus University † Corresponding author：E-Mail：[email protected] from which oil and gas are eventually generated（ Tissot and

Copyright © 2020， JAPT 36 Characterizing controls on reservoir properties in unconventional shale and tight reservoirs

Welte, 1984; Hunt, 1996; Vandenbroucke and Largeau, 2007）. However, by the time a source rock reaches a thermal maturity necessary to become an unconventional reservoir, much of the primary kerogen has been transformed into bitumen and oil（ Rippen et al., 2013; Kondla et al., 2015; Emmanuel et al., 2016; Hackley and Cardott, 2016）. This is particularly true beyond peak oil generation. Viscous fluid bitumen is generated directly from kerogen at early stages of transformation（“ pre-oil ” bitumen; Curiale, 1986）. Upon further thermal maturation fluid bitumen will undergo transformation into a solid product（ solid bitumen） and lighter hydrocarbons（ oil and gas）. Solid bitumen can also be generated from secondary cracking of oil（“ post- oil” bitumen; Curiale, 1986）. Pre-oil bitumen generally has low mobility owing to its high viscosity, and therefore pre-oil Fig. 1 Map of western Canada showing outlines of the solid bitumen typically represents an in-situ transformation of Montney Formation and Duvernay Formation kerogen. In contrast, post-oil solid bitumen is generated from oil as well as study areas. which had high mobility and pore-filling tendencies. As a result, post-oil solid bitumen is often observed to have filled primary pore spaces between detrital grains and within fossil chambers, and commonly envelops early diagenetic mineral cements Starting in 2018, JOGMEC and NRCan extended their （e.g., Loucks and Reed, 2014）. The Duvernay Formation shale collaboration to the Duvernay Formation which is a true source reservoir contains both pre- and post-oil solid bitumen, while rock and self-sourced shale reservoir in Alberta（ Fig. 1）. The the Montney Formation tight reservoir is dominated by post-oil, Duvernay work so far has identified mineral - organic matter pore-filling solid bitumen. relationships that strongly influence the pore system.

2. Background 3. Tight Reservoirs: Montney Project

JOGMEC’s motivation for conducting research on The Lower Triassic Montney Formation is primarily unconventional reservoirs is to support Japanese companies by composed of fine dolomitic sandstone and siltstone with improving exploration and production efficiency and reducing minor amounts of shale（ Davies, 1997; Zonneveld et al., 2010; investment risk. Over the last 10 years Japanese companies Chalmers and Bustin, 2012）. The up-dip（ depositionally have been active in many unconventional reservoirs around the and structurally） section of the Montney Formation hosts world, with the most activity centered in the United States and conventional oil and gas fields with exploration and production Canada. In many of these projects JOGMEC has collaborated dating back to the 1950s. The down-dip section of the Montney with Japanese companies and their North American partners by has been targeted as an unconventional tight gas reservoir providing technical analysis. In Canada, JOGMEC’s long term since 2005（ NEB, 2013）. The unconventional section of the collaboration partner in unconventional resources research is Montney Formation contains 449 TCF of marketable natural Natural Resources Canada（ NRCan）. This partnership has been gas, 14.5 billion barrels of marketable natural gas liquids, and very fruitful, as NRCan’s expertise in organic geochemistry 1.1 billion barrels of marketable crude oil（ NEB, 2013）. compliments JOGMEC’s expertise in laboratory petrophysical JOGMEC’s initial research into the Montney strived to analyses. NRCan and their subsidiary, the Geological Survey define the controls on reservoir quality, particularly porosity of Canada（ GSC）, also contribute a wealth of knowledge and and permeability. Wood et al.（ 2015）, Sanei et al.（ 2015）, and experience in the Western Canada Sedimentary Basin. Akihisa et al.（ 2018） demonstrated that solid bitumen in the This paper focuses on the collaborative efforts of JOGMEC Montney reservoir was strongly detrimental to permeability. and NRCan since 2014. From 2014 to 2017 JOGMEC and Sanei et al.（ 2015） and Wood et al.（ 2015, 2018） illustrated NRCan collaborated with Encana and Mitsubishi in the through the use of organic petrology and SEM imagery that Montney tight gas reservoir which occurs in the Canadian solid bitumen exhibited pore-filling textures and suggested that provinces of Alberta and British Columbia（ Fig. 1）. This solid bitumen formed as a secondary cracking product of oil collaborative research helped to define relationships between that had migrated into the reservoir at an earlier time. Akihisa organic matter and reservoir quality, and the processes et al.（ 2018） showed that these relationships could also be responsible for the Montney reservoir’s complex variations identified using cuttings rather than core. This work helped to in hydrocarbon composition（ condensate-gas ratio; CGR）. demonstrate the overlooked value of cuttings, which represent

石油技術協会誌 85 巻 1 号（2020） Levi J. Knapp, Shinnosuke Uchida, Takashi Nanjo, Tatsuya Hattori, Omid Haeri-Ardakani, Hamed Sanei 37

Fig. 2 （a） Regional Montney map from Wood and Sanei（ 2016） showing methane migration pathways based on calculation of excess methane. Excess methane is the “amount of methane greater than expected from the indigenous thermal maturity trend”.（ b） Location of 2 horizontal wells studied by Akihisa et al.（ 2018） which intersect a proposed meth- ane migration pathway. Map colors and contours are liquids-to-gas ratio from produced gas. Both wells were drilled from the same pad and extend in opposite directions. Pad location is indicated by the open circle1）.

1） Figures 2, 3, and 4 reprinted from International Journal of Coal Geology, vol. 197, Akihisa, K., Knapp., L.J., Sekine, K., Akai, T., Uchida, S., Wood, J.M., Ardakani, O.H., Sanei, H., Integrating mud gas and cuttings analyses to understand local CGR variation in the Montney tight gas reservoir, p.42−52, 2018, with permission from Elsevier.

J. Japanese Assoc. Petrol. Technol. Vol. 85, No. 1（2020） 38 Characterizing controls on reservoir properties in unconventional shale and tight reservoirs

huge, continuous data sources for every well, without the high intervals（ Fig. 3）. By integrating cuttings analysis with the cost of coring. mud gas results the authors demonstrated that solid bitumen The Montney Formation has condensate-gas ratios（ CGR） concentration, permeability, and gas composition were strongly that deviate from the regional thermal maturity trend. Wood correlated（ Fig. 4）. In particular, areas with low solid bitumen and Sanei（ 2016） suggested that areas of anomalously dry gas concentration had high permeability and abnormally dry gas compositions（ low CGR） were the result of up-dip migration of composition（ excess methane）. The results suggested that gas that was generated deeper in the basin（ Fig. 2a）. Part of the methane migrated up-dip along high permeability corridors research conducted by JOGMEC was aimed at identifying the that were at least partially controlled by the concentration of controls on CGR and methane migration pathways. In a study solid bitumen. Kato et al.（ 2017） was also able to map CGR of two horizontal wells in an area of high lateral CGR variation distribution and methane migration pathways on a regional （Fig. 2b）, Akihisa et al.（ 2018） integrated mud gas and cuttings scale by analyzing well and seismic data. analyses to examine the lateral variation in rock properties 4. Shale Reservoirs: Duvernay Project and gas composition at high resolution along the length of the horizontal sections. By analyzing mud gas composition, The Duvernay Formation is an Upper Devonian calcareous- the study confirmed that gas composition was highly variable siliceous source rock and unconventional shale reservoir in along the lateral sections, even within the same stratigraphic the province of Alberta. Leduc Formation reefs and Grosmont

Fig. 3 （a） Well trajectories for two horizontal wells in which cuttings and mud gas were analyzed. △ Z is the vertical depth from a stratigraphic datum to the well bore, and is used to stratigraphically normalize the mud gas and cuttings data and differentiate lateral from stratigraphic variations. Yellow and beige colors represent Zone B3 and Zone C1, respectively.（ b） Stratigraphically normalized mud gas data shows that mud gas wetness is laterally variable, even within the same stratigraphic intervals. Green and fuchsia colored data points are mud gas wetness data from the N-1 and S-1 wells, respectively. Figures after Akihisa et al（. 2018）1）.

石油技術協会誌 85 巻 1 号（2020） Levi J. Knapp, Shinnosuke Uchida, Takashi Nanjo, Tatsuya Hattori, Omid Haeri-Ardakani, Hamed Sanei 39

platform carbonates that occur on the margins of the basin fraction of the total porosity, and TOC and porosity are and as intrabasinal reef chains shed carbonate sediment into positively correlated（ Fig. 5）. However, high TOC samples have the basin at the time of Duvernay deposition（ Switzer et al., less porosity than expected, causing scatter in the TOC-porosity 1994; Knapp et al., 2017, 2019） and also host conventional relationship. It is interpreted that organic matter in high- carbonate reservoirs that were charged by Duvernay-sourced TOC samples is more load-bearing than in low-TOC samples, hydrocarbons（ Creaney et al., 1994; Fowler et al., 2001）. Large and organic-hosted porosity in high-TOC samples is more sections of the Duvernay Formation are highly siliceous, owing likely to be compacted, similar to results from the Marcellus to high concentrations of biogenic silica from radiolaria and Formation（ Milliken et al., 2013）. Much of the scatter in the sponge spicules（ Knapp et al., 2017; Dong et al., 2018; Harris TOC-porosity relationship can be explained by considering the et al., 2018）. The Duvernay Formation contains 76.6 TCF of ratio of compaction-resistant biogenic silica to compressible

marketable natural gas, 6.3 billion barrels of marketable natural organic matter（ SiO2_bio/TOC ratio）. Microcrystalline quartz gas liquids, and 3.4 billion barrels of marketable crude oil is widespread throughout the matrix due to early dissolution （NEB, 2017）. of siliceous radiolarian skeletons and reprecipitation of silica. As the Duvernay Formation is a true source rock and This biogenic silica is positively correlated to hardness, self-sourced shale reservoir, organic-hosted porosity brittleness, and Young’s modulus（ Dong et al., 2018）. High （predominantly within solid bitumen） comprises a major concentrations of rigid microcrystalline quartz relative to

Fig. 4 Analysis of mud gas and cuttings properties in two horizontal Montney wells reveals that（ a） solid bitumen satura- tion（ Ssb） is negatively correlated to NMR permeability,（ b） Ssb is positively correlated to mud gas wetness, and（ c ） that mud gas wetness is negatively correlated to permeability. Figures from Akihisa et al（. 2018）1）.

J. Japanese Assoc. Petrol. Technol. Vol. 85, No. 1（2020） 40 Characterizing controls on reservoir properties in unconventional shale and tight reservoirs

compressible organic matter（ SiO2_bio/TOC） result in enhanced total porosity（ Fig. 6） and increased organic pore size（ Fig.6 and Fig. 7）. The phenomenon can be ascribed to differential compaction. In highly siliceous samples, rigid load-bearing matrix frameworks that were created during early diagenesis likely limit compaction, resulting in greater preservation of primary inorganic porosity and secondary organic pores that were generated within ductile organic matter during thermal maturation.

5. Summary

Organic matter has a strong influence on petrophysical properties in unconventional reservoirs. It is important to recognize that these relationships will not be the same in tight reservoirs and shale reservoirs. In the Montney tight gas reservoir solid bitumen is the remnant of migrated oil, Fig. 5 Rock-Eval TOC vs helium porosity for samples and occludes pores and pore throats, limits permeability, and from 3 Duvernay wells（“ Fox”＝Chevron impacts produced gas CGR by influencing the location of up- HZ Foxck 08-15-062-18W5; “Kay”＝Chevron KaybobS 14-20-059-19W5; “Sax”＝ECA Saxon dip methane migration. In the Duvernay self-sourced shale 102/11-08-062-24W5）. Arrows indicate trends reservoir solid bitumen is a major host of porosity, leading of Fox Creek（ black） and KaybobS（ orange） to positive correlations between TOC and porosity. However, data. if TOC is too high relative to rigid matrix minerals such as

Fig. 6 TOC vs helium porosity, overlain by NMR T2 curves for samples from the “Fox” well. High SiO2_bio/TOC corre- sponds to higher total porosity per wt.% TOC（ i.e. steeper slope）. NMR T2 curves（ green） are a proxy for pore size, with larger T2 representative of larger pores. Colored bands represent pore diameter ranges of 1 – 10 nm（ green）, 10 – 100 nm（ pink）, and 100 – 1000 nm（ blue） based on fitting of NMR T2 and MICP pore throat size distribution curves. NMR T2 curves show that the upper, siliceous trend（ red line） is dominated by pores in the 10 – 100 nm range, whereas the lower, less siliceous trend（ black line） is dominated by pores with diameter ＜10 nm. Note: The Fox143 sample（ low TOC, low porosity carbonate） was included in both datasets as a control point in the low porosi-

ty range. Its SiO2_bio/TOC is meaningless due to very low concentrations of both SiO2_bio and TOC.

石油技術協会誌 85 巻 1 号（2020） Levi J. Knapp, Shinnosuke Uchida, Takashi Nanjo, Tatsuya Hattori, Omid Haeri-Ardakani, Hamed Sanei 41

SI unit conversion factor

cf × 2.831685 E － 02 ＝ m3 bbl × 1.589874 E － 01 ＝ m md × 9.86923 E － 16 ＝ m

References Akihisa, K., Knapp., L.J., Sekine, K., Akai, T., Uchida, S., Wood, J.M., Ardakani, O.H., and Sanei, H., 2018: Integrating mud gas and cuttings analyses to understand local CGR variation in the Montney tight gas reservoir. Int. J. Coal Geol. 197, 42−52. Chalmers, G.R.L., and Bustin, R.M., 2012: Geological evaluation of Halfway-Doig-Montney hybrid gas shale-tight gas reservoir, northeastern British Columbia. Mar. Pet. Geol. 38, 53−72. Creaney, S., Allan, J., Cole, K.S., Fowler, M.G., Brooks, P.W., Osadetz, K.G., Macqueen, R.W., Snowdon, L.R., and Riediger, C.L., 1994: Petroleum generation and migration in the western Canada Sedimentary Basin. In: Mossop, G.D., Shetsen, I. Eds.;（comps.), Canadian Society of Fig. 7 FIB-SEM images of samples with high（ A） Petroleum Geologists and Alberta Research Council, 31. and low（ B） SiO2_bio/TOC exhibit contrasting organic pore sizes. A） Solid bitumen（ dark 455–468. grey） within the intracrystalline space of a Curiale, J.A., 1986: Origin of solid bitumens, with emphasis on microcrystalline quartz-rich matrix（ most of biological marker results. Org. Geochem., 10, 559–580. the light grey material）. Large organic-hosted Davies, G.R., 1997: The Triassic of the Western Canada pores are preserved, potentially due to the com- sedimentary basin: tectonic and stratigraphic framework, paction-resistant rigid siliceous framework. B） paleogeography, paleoclimate and biota. Bull. Can. Petrol. Solid bitumen in a less siliceous matrix contains much smaller pores, potentially due to the high- Geol. 45, 434−460. er compressibility of the matrix and greater Dong, T., Harris, N.B., Knapp, L.J., McMillan, J.M., Bish, D.L., effective stress placed on the organic matter 2018: The effect of thermal maturity on geomechanical particles. Bright white colors are imaging properties in shale reservoirs: An example from the artifacts from charge buildup on the sample Upper Devonian Duvernay Formation, Western Canada surface. Sedimentary Basin. Mar. Pet. Geol. 97, 137−153. Emmanuel, S., Eliyahu, M., Day-Stirrat, R.J., and Hofmann, R., 2016: Impact of thermal maturation on nano-scale elastic properties of organic matter in shales. Mar. Pet. Geol. 70, biogenic silica, organic- and inorganic porosity will be more 175–184. prone to compaction. Ongoing research at JOGMEC-TRC in Fowler, M.G., Stasiuk, L.D., Hearn, M., Obermajer, M., 2001: collaboration with NRCan continues to delineate the complex Devonian hydrocarbon source rocks and their derived relationships between organic matter, minerals, and reservoir oils in the Western Canada Sedimentary Basin. Bull. Can. properties in various types of unconventional reservoirs. Petrol. Geol. 49, 117–148. Hackley, P.C., and Cardott, B.J., 2016: Application of organic Acknowledgements petrography in North America shale petroleum systems: a JOGMEC would like to thank our research partners at review. Int. J. Coal Geol. 163, 8–51. NRCan for all of their contributions, discussion, and knowledge Harris, N.B., McMillan, J.M., Knapp, L.J., and Mastalerz, M., sharing throughout the history of our partnership. Thank 2018: Organic matter accumulation in the Upper Devonian you to Encana and Mitsubishi for Montney samples and data, Duvernay Formation, Western Canada Sedimentary Basin, from sequence stratigraphic analysis and geochemical and for technical discussions. Thank you to the lab teams at proxies. Sediment. Geol. 376, 185–203. the JOGMEC Technology Research Center in Chiba and the Hunt, J.M., 1996: Petroleum Geochemistry and Geology, Geological Survey of Canada in Calgary for their continued Second ed.; W.H. Freeman and Company, New York, p. efforts in generating high quality data. 743. Jarvie, D.M., 2012: Shale Resource Systems for Oil and Gas:

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Part 1 – Shale-gas Resource Systems. In: J.A. Breyer, ed.; shales. Org. Geochem. 63, 18–36. Shale reservoirs – Giant resources for the 21st century. Sanei, H., Wood, J.M., Ardakani, O.H., Clarkson, C.R., AAPG Memoir 97, 69−87. and Jiang, C., 2015: Characterization of organic matter Kato, A., Akihisa, K., Knapp, L., de Groot, M., and Yamazaki, fractions in an unconventional tight gas siltstone reservoir. K., 2017: Sweet Spot Mapping in the Montney Tight Gas Int. J. Coal Geol. 150−151, 296–305. Reservoir. Abu Dhabi International Petroleum Exhibition Switzer, S.B., Holland, W.G., Christie, D.S., Graf, G.C., & Conference, 13−6 November, Abu Dhabi, UAE. SPE- Hedinger, A.S., McAuley, R.J., Wierzbicki, R.A., and 188863-MS. Packard, J.J., 1994: TheWoodbend-Winterburn strata of Knapp, L.J., McMillan, J.M., and Harris, N.B., 2017: A the Western Canada Sedimentary Basin. In: Mossop, G.D., depositional model for organic-rich Duvernay Formation Shetsen, I. Eds.;, Geological Atlas of the Western Canada mudstones. Sediment. Geol. 347, 160–182. Sedimentary Basin. Geological Survey of Canada（ Chapter Knapp, L.J., Nanjo, T., Uchida, S., Ardakani, O.H., and Sanei, 12）. H., 2018: Investigating Influences on Organic Matter Tissot, B., Welte, D.H., 1984: Petroleum Formation and Porosity and Pore Morphology in Duvernay Formation Occurrence, Second ed.; Springer, Berlin（ 699p）. Organic-Rich Mudstones. SPWLA 24th Formation Vandenbroucke, M., Largeau, C., 2007: Kerogen origin, Evaluation Symposium of Japan, 11-12 October, Chiba, evolution and structure. Org. Geochem. 38, 719–833. Japan. SPWLA-JFES-2018-B. Wood, J.M., Sanei, H., 2016: Secondary Migration and Knapp, L.J., Harris, N.B., and McMillan, J.M., 2019: A Leakage of Methane from a Major Tight-Gas System. sequence stratigraphic model for the organic-rich Nature Communications, 22, 1–9. Upper Devonian Duvernay Formation, Alberta, Canada. Wood, J.M., Sanei, H., Curtis, M.E., and Clarkson, C.R., 2015: Sediment. Geol. 387, 152−181. Solid bitumen as a determinant of reservoir quality in an Kondla, D., Sanei, H., Embry, A., Ardakani, O.H., and unconventional tight gas siltstone play. Int. J. Coal Geol. Clarkson, C.R., 2015: Depositional environment and 150−151, 287–295. hydrocarbon potential of the middle Triassic strata of Wood, J.M., Sanei, H., Ardakani, O.H., Curtis, M.E., Akai, the Sverdrup Basin, Canada. Int. J. Coal Geol. 147−148, T., and Currie, C., 2018: Solid bitumen in the Montney 71–84. Formation: Diagnostic petrographic characteristics and Loucks, R.G., Reed, R.M., Ruppel, S.C., and Jarvie, D.M., 2009: significance for hydrocarbon migration. Int. J. Coal Geol. Morphology, genesis and distribution of nanometer-scale 198, 48−62. pores in siliceous mudstones of the Mississippian Barnett Zonneveld, J.-P., MacNaughton, R.B., Utting, J., Beatty, Shale. J. Sediment. Res. 79, 848−861. T.W., Pemberton, S.G., and Henderson, C.M., 2010: Loucks, R.G., and Reed, R.M., 2014: Scanning-electron- Sedimentology and ichnology of the lower Triassic microscope petrographic evidence for distinguishing Montney Formation in the pedigree-ring/border-Kahntah organic-matter pores associated with depositional organic river area, Northwestern Alberta and northeastern British matter versus migrated organic matter in mudrocks. Gulf Columbia. Bull. Can. Petrol. Geol. 58, 115−140. Coast Association of Geological Societies Journal, 3, 51−60. Mastalerz, M., Schimmelmann, A., Drobniak, A., and Chen, Y., シェールおよびタイト貯留層を対象とした 2013: Porosity of Devonian and Mississippian New Albany Shale across a maturation gradient: Insights from organic 貯留層キャラクタリゼーション petrology, gas adsorption, and mercury intrusion. AAPG （ ） Bulletin, 97 10 , 1621−1643. リーヴァイ ナップ・内田 真之介・南條 貴志 Milliken, K.L., Rudnicki, M., Awwiller, D.N., Zhang, T., 2013: Organic matter-hosted pore system, Marcellus Formation 服部 達也・オミド アルダカニ・ハメド サネイ （Devonian）, Pennsylvania. AAPG Bulletin, 97（2）, 177− 200. JOGMEC では，2014 年よりカナダ天然資源省および同 National Energy Board, BC Oil & Gas Commission, 国タイトガス鉱区の開発事業者と共同で，シェールやタイ Alberta Energy Regulator, BC Ministry of Natural Gas ト貯留層の評価技術の開発に取り組んできた。本稿では， Development. The Ultimate Potential for Unconventional 年 月 日に開催された石油技術協会春季講演会探 Petroleum from the Montney Formation of British 2019 6 12 Columbia – Energy Briefing Note, November 2013. 鉱技術シンポジウムでの講演内容をもとに，西カナダの上 National Energy Board. Duvernay Resource Assessment – 部デボン系 Duvernay 層と下部三畳系 Montney 層を対象と Energy Briefing Note, November 2017. して，有機物のタイプ・含有量や岩石の鉱物組成の違いが Rippen, D., Littke, R., Bruns, B., and Mahlstedt, N., 2013: 貯留層の性状に与える影響について分析した結果について Organic geochemistry and petrography of Lower 報告する。 Cretaceous Wealden black shales of the Lower Saxony Duvernay 層は従来型油ガス田の根源岩層準として広く Basin: the transition from lacustrine oil shales to gas 認知されている self-source 型のシェール貯留層であるの

石油技術協会誌 85 巻 1 号（2020） Levi J. Knapp, Shinnosuke Uchida, Takashi Nanjo, Tatsuya Hattori, Omid Haeri-Ardakani, Hamed Sanei 43

に対し，Montney 層は細粒な砂岩あるいはシルト岩から 貯留層の性状に多大な影響を及ぼす一方，その影響の仕方 成るタイト貯留層であり，そこに賦存する炭化水素は上下 が両層で全く異なることが明らかとなった。この成果は， あるいは側方に分布する別の層準から供給されたものと考 self-source 型のシェール貯留層とタイト貯留層のそれぞれ えられている。これまでの研究を通じて，Duvernay 層， における孔隙の形成，保持プロセスや貯留層性状分布の不 Montney 層の双方において，岩石内の固体ビチュメンが 均質性を理解するうえで，重要な示唆を与えるものである。

J. Japanese Assoc. Petrol. Technol. Vol. 85, No. 1（2020）