Hydrocarbon Distribution in the Mannville Waseca Member, Edam Oil Field, West-central Saskatchewan

Transcription

1 Hydrocarbon Distribution in the Mannville Waseca Member, Edam Oil Field, West-central Saskatchewan Peter Hill 1 Information from this publication may be used if credit is given. It is recommended that reference to this publication be made in the following form: Hill, P. (2017): Hydrocarbon distribution in the Mannville Waseca Member, Edam oil field, west-central Saskatchewan; in Summary of Investigations 2017, Volume 1, Saskatchewan Geological Survey, Saskatchewan Ministry of the Economy, Miscellaneous Report , Paper A-3, 21p. Abstract The Lower Cretaceous Mannville Group Waseca Member is one of the best producing heavy oil reservoirs in Saskatchewan. The pools surrounding the town of Edam in west-central Saskatchewan have seen extensive oil production from several sandstone bodies found at a shallow depth (approximately 400 m) within the Waseca Member. Detailed analysis of cores and geophysical well logs from the study area resulted in the identification of three separate sandstone reservoirs, which are, in ascending order: 1) a channel reservoir facies near the base of the Waseca Member; 2) the Lower Waseca reservoir facies; and 3) the Upper Waseca reservoir facies. These reservoirs typically consist of basal homogeneous, fine- to medium-grained, poorly consolidated, well-sorted sandstones, overlain by interbedded sandstone and shale, indicative of a fining-upward point bar sequence. These sedimentary features, combined with the presence of syneresis cracks and a lowdiversity trace fossil assemblage, suggest a brackish, tidally influenced estuarine depositional system. Using a combination of production maps, isopach and structure contour maps, and cross-sections, this paper will show the distribution and production of many of the producing reservoirs in the Waseca Member in west-central Saskatchewan. Keywords: Waseca Member, Mannville, Cretaceous, estuarine, heavy oil, channel, point bar, west-central Saskatchewan 1. Introduction The Lower Cretaceous Mannville Group in west-central Saskatchewan has had extensive heavy oil production since the 1950s. There are several major producing oil units in the study area; however, this study will focus on oil production only from the Waseca Member. This study was completed to better understand the internal stratigraphy and spatial distribution of oil reservoirs in the area, specifically the estuarine channels identified within the Waseca Member. The study area encompasses from Township 48, Range 19 west of the Third Meridian (19W3) to Township 49, Range 20 west of the Third Meridian (20W3). The study area is focused in and around four oil-producing pools: the Edam North, Edam, Edam South and Edam East pools (Figure 1). In Saskatchewan, Waseca Member oil production comes from a number of sandstone reservoirs. Traditionally, Waseca Member oil is produced using conventional methods, targeting thin, sheet-like sandstone bodies. 2. Previous Work Previous studies focused on Waseca Member lithostratigraphy and production outside of the Edam area. A stratigraphic framework study for the Upper Mannville Group was completed by Morshedian et al. (2012). Christopher (2003) completed a comprehensive study of the Lower Cretaceous Mannville Group in which he investigated geological setting and oil reserves throughout Saskatchewan. 1 Saskatchewan Ministry of the Economy, Saskatchewan Geological Survey, 201 Dewdney Avenue East, Regina, SK S4N 4G3 Although the Saskatchewan Ministry of the Economy has exercised all reasonable care in the compilation, interpretation and production of this product, it is not possible to ensure total accuracy, and all persons who rely on the information contained herein do so at their own risk. The Saskatchewan Ministry of the Economy and the Government of Saskatchewan do not accept liability for any errors, omissions or inaccuracies that may be included in, or derived from, this product. Saskatchewan Geological Survey 1 Summary of Investigations 2017, Volume 1

2 Figure 1 Location of the study area in west-central Saskatchewan, and Waseca Member oil pools. Locations of cross-sections A-A and B-B are also delineated. Abbreviations on map: T = Township, R = Range, W = West. Saskatchewan Geological Survey 2 Summary of Investigations 2017, Volume 1

3 Lorsong (1979, 1980) focused on lithostratigraphy and spatial distribution of sandstone bodies in the Waseca Member in the Celtic field (Township 51, Range 22W3 to Township 52, Range 24W3), northwest of the Edam oil field, and concluded the sands had been deposited in a nearshore, marine environment. Putnam (1980, 1982) also focused on the Celtic field; however, he concluded that sand bodies in the Waseca Member were deposited in a fluvial system. MacEachern (1984) modified and expanded on Lorsong s lithofacies descriptions to construct a thorough paleoenvironmental interpretation of the Waseca Member in the Lloydminster area, roughly 75 km west of the current study area. Van Hulten (1984) identified a restricted channel facies and a widespread regional facies in the Waseca Member in the Pikes Peak oil field, also northwest of the Edam oil field, in Township 50, Ranges 23 and 24 west of the Third Meridian. 3. Geological Setting and Stratigraphy The Waseca Member is Albian in age and is part of the Lower Cretaceous Mannville Group (Figure 2). The Waseca Member is unconformably overlain by interbedded shaly sandstones that make up the Lower Cretaceous McLaren Member, and disconformably lies above the Sparky Member, which is composed of silty shales that may be capped by coal (Vigrass, 1977). Beneath the Mannville Group is the sub-cretaceous unconformity surface, which is one of the main depositional controls on the Mannville. Within the study area, the Mannville is draped over top of the Devonian Duperow Formation (Christopher, 2003). Mannville Group sediments are thickest over sub-cretaceous structural lows and thinnest on sub-cretaceous structural highs (Jackson, 1984). Van Hulten (1984) identified two different types of facies within the Pikes Peak oil field: 1) a regional facies, and 2) a channel facies (Figure 2). The regional facies is composed of 15 to 20 metres of interbedded shale and siltstone at the base of the Waseca Member. This basal unit is overlain by two oil-producing sandstone beds, informally named the Lower Waseca and the Upper Waseca, that range from 1 to 6 metres in thickness. The Upper and the Lower Waseca reservoirs are separated by a thin (1 metre) shale that may grade into a coal. Separating the McLaren from the Upper Waseca sandstone is a shale, up to 7 metres thick, that contains ironstone. Van Hulten s channel facies consists of three correlatable units (Figure 2). The basal unit is composed of homogeneous, fine- to medium-grained quartz sandstone up to 20 metres thick. The basal sandstone is overlain by an interbedded siltstone and shale unit that is dominated by wavy, lenticular and flaser bedding. The top of the channel facies is composed of sideritic shale that acts as a reservoir seal. The Waseca Member in the Edam area and surrounding pools is thinner, but has similar stratigraphy to the Pikes Peak oil field as described by Van Hulten (1984), in that both a regional facies unit and a channel facies unit were identified; however, unlike the Pikes Peak pool, the regional facies may overlie the channel facies in the Edam area. 4. Methods Core from 17 wells was examined in detail, to analyze lithology, stratigraphy, sedimentary structures and biogenic structures. All of the contour maps in this paper were created using data derived from core and geophysical well logs. Structure and isopach maps were created using data from 489 wells within the study area. Oil cut was calculated and contoured, to illustrate the differences between the reservoirs, as well as to highlight areas of optimal production within the Waseca Member. All of the maps were used to show the factors influencing reservoir and hydrocarbon distribution. All of the maps for this study were created in Golden Software Inc. s Surfer version 12, using a kriging algorithm. Van Hulten s (1984) Pikes Peak Waseca terminology was used as a standard for describing Waseca facies within the study area. Saskatchewan Geological Survey 3 Summary of Investigations 2017, Volume 1

4 Figure 2 Left: Stratigraphic correlation chart of west-central Saskatchewan (modified from Saskatchewan Ministry of the Economy, 2014). Right: Illustration of the relationship between Van Hulten s (1984) regional Waseca facies and channel facies. Saskatchewan Geological Survey 4 Summary of Investigations 2017, Volume 1

5 5. Reservoir Facies Descriptions, Distribution, and Interpretation of Depositional Environments For the purpose of this study, three main reservoir facies were identified in the Waseca Member: 1) a channel reservoir facies, 2) a Lower Waseca reservoir facies, and 3) an Upper Waseca reservoir facies. These are equivalent to the channel and regional Waseca reservoir facies identified by Van Hulten (1984; Figure 2). Each reservoir has its own unique lithology, sedimentary features and depositional environment; however, only the characteristics of the channel reservoir facies and the Lower Waseca reservoir facies will be discussed in detail in this study. The Upper Waseca reservoir facies will not be discussed because it has limited production, is typically thin and areally limited. The channel reservoir facies is thicker, but has a smaller areal distribution, whereas the Lower Waseca reservoir facies is found throughout the study area and is often stacked on top of the channel reservoir facies where both are present. a) Channel Reservoir Facies Description In the Edam area, the base of the channel reservoir facies is made up of moderately sorted, subangular to rounded, medium-grained quartz sandstone. Typically the sandstone has a massive appearance due to high levels of oil staining (Figure 3A); however, planar cross-beds are locally visible at the base of the channel (Figure 3B), just above the Sparky Member. Lag deposits consisting of angular to well-rounded rip-up clasts (Figure 3C) are commonly found at the base of the channel reservoir facies, and shale breccia (Figure 3D) up to a metre thick is locally present within this facies. Figure 3 Core photographs illustrating characteristic features of the channel reservoir facies: A) medium-grained massive sandstone with intense oil saturation, from well 111/ W3/00; 81H031 at a depth of m; B) planar cross-bedding at the base of the channel, from same well as in photo A, at a depth of m; C) rip-up clasts, from same well as in photo A; D) shale breccia, from well 101/ W3/00; 79H057 at a depth of m. Saskatchewan Geological Survey 5 Summary of Investigations 2017, Volume 1

6 Inclined heterolithic stratification (IHS) consisting of grey shale, silt and fine- to medium-grained sandstone (Figure 4A) overlies homogeneous sandstone at the base of the channel reservoir facies. Planar bedding is the most common sedimentary structure. Gyrolithes trace fossils are relatively common (Figure 4B), but they are the only trace fossils seen in the core of this facies. Figure 4 Core photographs illustrating other characteristic features of the channel reservoir facies: A) inclined heterolithic stratification, from well 111/ W3/00; 95H208 at a depth of 434 m; B) Gyrolithes trace fossils, from well 111/ W3/00; 86B206 at a depth of m; C) silty grey to black shale (top of photo) at top of the channel, from well 111/ W3/00; 79H057 at a depth of 417 m; D) siderite nodule, from well 111/ W3/00; 79J043 at a depth of m. The top of the channel reservoir facies consists of a silty grey to black shale (Figure 4C). The shale is very similar in appearance to the shales in IHS beds found below it. Pyrite and siderite nodules are very common within this unit (Figure 4D). Thin planar laminations and wavy bedding are the dominant sedimentary structures (e.g., Figures 3B, 4A, 4C). Distribution The channel reservoir facies varies from 0.9 to 19.3 metres in thickness (Figure 5), with an average thickness of 6.5 metres, and trends northeast-southwest. The thickest accumulations of channel deposits are in the southeastern corner of the study area, and the facies gradually thins to the west. A stratigraphic cross-section (line A-A on Figure 5) was developed using gamma ray signatures to illustrate the relationship of the channel reservoir to other beds within the Waseca Member (Figure 6; see end of this report). Saskatchewan Geological Survey 6 Summary of Investigations 2017, Volume 1

7 Figure 5 Isopach map of the channel reservoir facies, and location of cross-section A-A, which is shown in Figure 6 (see end of this report). Contour interval is 1 metre. Abbreviations: T = Township, R = Range, C.I. = contour interval. Depositional Environment Sedimentology, ichnology, sedimentary structures and the overall reservoir facies relationships are all indicative of a marginal-marine estuarine channel depositional environment. Basal homogeneous sandstone overlain by IHS beds and capped by shale is a classic example of a fining-upward point bar sequence. Rip-up clasts and planar bedding within the basal sandstone were deposited in a higher-energy regime, whereas IHS beds and shale all have sedimentary structures indicative of a lower-energy regime. The shale breccia is indicative of a bank collapse caused by erosion (Van Hulten, 1984). Small, low-diversity trace fossil assemblages are indicative of fluctuating salinities in a brackish estuarine depositional environment (Pemberton et al., 2001). The observed diminutive and monospecific Gyrolithes are indicative of a stressed trace fossil assemblage within an estuarine point bar system. Many of the features identified above are similar to the sedimentary features identified by Van Hulten (1984) for his channel reservoir facies in the Pikes Peak oil field, which also suggested an estuarine depositional setting. Saskatchewan Geological Survey 7 Summary of Investigations 2017, Volume 1

8 b) Lower Waseca Reservoir Facies Description Typically, the base of this reservoir facies is composed of heavily oil-stained, poorly consolidated, very fine- to finegrained, subrounded to rounded, well-sorted quartz sandstone (Figure 7A). Sedimentary features at the base are often obscured by pervasive oil staining; however, planar beds are locally visible. The Lower Waseca reservoir facies fines upward and grades into lenticular sandstone beds draped by mudstone (Figure 7B), similar to the IHS beds in the channel reservoir facies. Syneresis cracks are a common sedimentary feature within the muds (Figure 7C). Coalbearing seams and rootlets were also observed (Figure 7D); however, these features are not common within the study area. Figure 7 Core photographs illustrating characteristic features of the Lower Waseca reservoir facies: A oil-stained quartz sandstone, from well 111/ W3/00; 81B042 at a depth of 421 m; B) lenticular sandstone beds draped by mudstone, from well 111/ W3/00; 79H057 at a depth of m; C) syneresis cracks, from well 121/ W3/00; 81H031 at a depth of 433 m; D) rootlets within a silty mudstone, from well 111/ W3/00; 83G117 at a depth of 437 m. Distribution The Lower Waseca reservoir facies varies from 0.6 to 7.2 metres in thickness (Figure 8), with an average thickness of 1.6 metres. A stratigraphic cross-section (line B-B on Figure 8) was developed using gamma ray and density porosity signatures, to illustrate the relationship of the Lower Waseca reservoir to other beds within the Waseca Member (Figure 9; see end of this report). Saskatchewan Geological Survey 8 Summary of Investigations 2017, Volume 1

9 Figure 8 Isopach map of the Lower Waseca reservoir facies, and location of cross-section B-B, which is shown in Figure 9 (see end of this report). Contour interval is 1 metre. Abbreviations: T = Township, R = Range, C.I. = contour interval. Depositional Environment Although the sedimentology, sedimentary structures and fining-upward sequence observed within the Lower Waseca reservoir facies are very similar to the features identified within the channel reservoir facies, the Lower Waseca reservoir facies fines upward into heterolithic beds with flaser beds and mud drapes; this is indicative of an estuarine tidal flat or interfluve environment (MacEachern and Bann, 2008). Syneresis cracks are indicative of changes in salinity usually associated with brackish environments (Burst, 1965). Syneresis cracks were also identified in the Waseca Member in the Lloydminster area, and were interpreted as indicative of a brackish environment (MacEachern, 1984). 6. Isopach and Structural Mapping An isopach map was created for the entire Waseca Member (Figure 10) to illustrate that the member is thickest on the eastern edge of the study area and thins significantly to the south and southwest. Subtle north-south thickness variations (outlined by the red dashed lines in Figure 10) are discernible on the east side of the study area, as well as in Township 48 Range 19W3, and generally coincide with Duperow structural lows (Figure 11). The thickness of the Waseca Member varies from 16 to 44 metres. Saskatchewan Geological Survey 9 Summary of Investigations 2017, Volume 1

10 Figure 10 Isopach contour map of the Waseca Member. Contour interval is 2 metres. Note: Red dashed lines indicate areas of thick accumulation of Waseca Member sediments. Abbreviations: T = Township, R = Range, C.I. = contour interval. A structure contour map was created for the top of the Duperow Formation (Figure 11) to illustrate how the sub- Cretaceous surface has controlled deposition of the Waseca Member. When Figure 11 is compared to Figure 10, it is evident that structural highs within the Duperow Formation coincide with areas of thin accumulations of Waseca Member sediments, particularly in the southern part of the study area. Inversely, structural lows within the Duperow Formation correspond with areas of thick accumulations of Waseca Member sediments, especially on the eastern side of the study area. It should be noted, however, that, in places, Duperow Formation structural highs correspond with thick accumulations of Waseca Member sediments, as in the southern part of Township 49 Range 20W3. Saskatchewan Geological Survey 10 Summary of Investigations 2017, Volume 1

11 Figure 11 Structure contour map for the top of the Duperow Formation. Contour interval is 3 metres. Note: Red dashed lines indicate areas of Duperow Formation structural lows. Abbreviations: T = Township, R = Range, C.I. = contour interval. A structure contour map was also created for the top of the Waseca Member (Figure 12) to illustrate how reservoir sweet spots within the channel reservoir facies are associated with structural highs within the study area. Outlines of channel reservoir oil cut sweet spots (oil cut >60%) discussed later in the paper are overlain on top of the Waseca structural surface, to illustrate that sweet spots are more likely structure dependent and not facies dependent. The top of the Waseca Member is shallow throughout the study area, ranging from 400 to 515 metres below the surface (or 55 to 163 metres above sea level). Saskatchewan Geological Survey 11 Summary of Investigations 2017, Volume 1

12 Figure 12 Structure contour map for the top of the Waseca Member. Contour interval is 2 metres. Note: Pink lines represent oil cut sweet spots from the channel reservoir facies initial 3 months of production. Abbreviations: T = Township, R = Range, C.I. = contour interval. 7. Production a) Oil Production Oil cut maps were created for both the channel reservoir facies and the Lower Waseca reservoir facies within the Waseca Member, by identifying oil production and contouring the initial 3 months of oil production from each individual well, divided by the initial 3 months of oil production plus the initial 3 months of water production. The following equation explains the calculation of the 3-month oil cut: Initial 3 months of oil production / (initial 3 months of oil production + initial 3 months of water production) Saskatchewan Geological Survey 12 Summary of Investigations 2017, Volume 1

13 This same method was used to create an oil cut map after 5 years of oil production, to illustrate how production within the reservoir has changed over time. The following equation explains the calculation for the 5-year oil cut: Initial 5 years of oil production / (initial 5 years of oil production + initial 5 years of water production) Oil Cut for the Channel Reservoir Facies The initial 3 months oil cut for the channel reservoir facies (Figure 13) illustrates the sweet spots within the reservoir. When compared to Figure 5, it is evident that the oil sweet spots correlate to thinner parts of the channel, and the thickest parts of the channel reservoir facies (e.g., in the extreme southeast of the study area) are associated with lower oil cuts. The oil cut map created for the initial 5 years of production within the channel reservoir facies (Figure 14) illustrates how the sweet spots have a north-south trend just east of the town of Edam (i.e., in the northwest quarter of Township 48, Range 19W3) that correlate with the structurally highest area of the Waseca Member (see Figure 12). Figure 13 Initial 3 months oil cut within the channel reservoir facies. Contours are in 0.10 intervals (10 percent). Abbreviations: T = Township, R = Range, C.I. = contour interval. Saskatchewan Geological Survey 13 Summary of Investigations 2017, Volume 1

14 Figure 14 Initial 5 years oil cut within the channel reservoir facies. Contours are in 0.10 intervals (10 percent). Abbreviations: T = Township, R = Range, C.I. = contour interval. These oil cut maps illustrate that, over the life of the wells in the channel reservoir facies, water production increases and oil production decreases. Oil Cut for the Lower Waseca Reservoir Facies The initial 3 months of production for the Lower Waseca reservoir (Figure 15) reveal that oil cut throughout this reservoir is fairly consistent throughout the study area. The oil cut map created for the initial 5 years of production within the Lower Waseca reservoir (Figure 16) illustrates that after a significant length of time the oil cut remains relatively high. Figures 15 and 16 were created using wells that produced exclusively within the Lower Waseca reservoir. There are wells within the study area that produce from both the channel reservoir and the Lower Waseca reservoir. Saskatchewan Geological Survey 14 Summary of Investigations 2017, Volume 1

15 Figure 15 Initial 3 months oil cut within the Lower Waseca reservoir. Contours are in 0.10 intervals (10 percent). Abbreviations: T = Township, R = Range, C.I. = contour interval. The oil cut maps for both the channel and Lower Waseca reservoirs have similar characteristics in that the sweet spots are associated with Waseca Member structural highs (see Figure 12). All of the oil production maps illustrate that the best oil cuts are independent of reservoir facies thickness. As mentioned previously, the thickest part of the channel reservoir facies in the southeast corner of the study area has little to no oil cut, indicating oil is either structurally controlled or associated with stratigraphic pinch-outs. Saskatchewan Geological Survey 15 Summary of Investigations 2017, Volume 1

16 Figure 16 Initial 5 years oil cut within the Lower Waseca reservoir. Contours are in 0.10 intervals (10 percent). Abbreviations: T = Township, R = Range, C.I. = contour interval. b) Gas Production A gas production map (Figure 17) was created to show the distribution of natural gas production associated with the heavy oil production within the study area. The map was developed by identifying individual Waseca Member wells with associated gas production, and contouring the cumulative production. Gas production is typically associated with the Upper and Lower Waseca reservoirs. Gas production is likely associated with reservoir pinch-out, as the Lower Waseca reservoir facies thins significantly just to the north of the area of highest gas production (compare Figure 17 to Figure 8). Saskatchewan Geological Survey 16 Summary of Investigations 2017, Volume 1

17 Figure 17 Cumulative natural gas production for the Waseca Member. Contour interval is 1000 metres. Abbreviations: T = Township, R = Range, C.I. = contour interval. 8. Reservoir Characteristics Typically, the most productive wells within the channel reservoir facies have a blocky, very low gamma ray signature, with values that range between 15 and 45 API (see Figure 6, at end of this report). This is due to fairly clean homogeneous sand with very little clay material. The interbedded fining-upward sequence is illustrated by an increasing gamma ray signature that is higher than 45 API. The Lower Waseca reservoir facies has slightly higher gamma ray values, ranging between 25 and 60 API (see Figure 9, at end of this report). The best oil production occurs in reservoirs with gamma ray signatures less than 45 API. The channel reservoir facies has an average porosity of 34.5%, based on values from neutron porosity and density porosity geophysical well logs, and the Lower Waseca reservoir facies has an average porosity of 33.1%. Within the channel facies, typically the best oil production is associated with porosity values greater than 30% (Figure 18). It is Saskatchewan Geological Survey 17 Summary of Investigations 2017, Volume 1

18 important to note that nearly all of the highest producing wells shown in Figure 18 are associated with the channel reservoir facies, indicating this reservoir facies is the top producer within the study area due to excellent porosity and presence of clean sandstone, as indicated by the low gamma ray signatures. Figure 18 Map of channel reservoir facies porosity and wells that have produced over 250,000 barrels (bbls) of oil. Contour interval is 1 metre. Note: Wells with the highest oil production are typically associated with the highest porosity values, and these coincide with the channel reservoir facies. Abbreviations: T = Township, R = Range, C.I. = contour interval. Saskatchewan Geological Survey 18 Summary of Investigations 2017, Volume 1

19 9. Summary Waseca Member heavy oil reservoirs are found at a shallow depth within the study area, ranging from 400 to 545 metres below surface. Three sandstone reservoirs within the Waseca Member were identified. These are, in descending order: 1) Upper Waseca reservoir; 2) Lower Waseca reservoir; and 3) channel reservoir. The Lower Waseca reservoir and the channel reservoir have the most prolific production within the study area. Waseca Member reservoirs were deposited in a brackish, tidally influenced estuarine system, characterized by fining-upward point bar sequences, tidal flats, IHS beds, a low-diversity trace fossil assemblage and syneresis cracks. Waseca Member deposition was somewhat controlled by the sub-cretaceous erosional surface, where thick accumulations of Waseca Member sediments overlie structural lows in the Duperow Formation, and thin accumulations of Waseca Member sediments are overtop of structural highs in the Duperow Formation. The combination of reservoir isopach maps, oil cut maps and reservoir characteristics illustrate that the channel reservoir facies are more productive than the regional Upper and Lower Waseca reservoirs. 10. Acknowledgments The author would like to thank Ashton Chaykowski and Rae McClintock for their assistance in collecting data for this study. I would also like to thank all of the staff at the Saskatchewan Subsurface Geological Lab, especially Dan Kohlruss and Arden Marsh, for numerous discussions about stratigraphy, oil production and sedimentology. 11. References Burst, J.F. (1965): Subaqueously formed shrinkage cracks in clay; Journal of Sedimentary Petrology, v.35, p Christopher, J.E. (2003): Jura-Cretaceous Success Formation and Lower Cretaceous Mannville Group of Saskatchewan; Saskatchewan Industry and Resources, Report 223, CD-ROM. Jackson, P.C. (1984): Paleogeography of the Lower Cretaceous Mannville Group of western Canada; in Elmworth Case Study of a Deep-basin Gas Field, Masters, J.A. (ed.), American Association of Petroleum Geologists, Memoir 38, p Lorsong, J.A. (1979): Lithofacies of the Lower Cretaceous Mannville Group, west-central Saskatchewan; in Summary of Investigations 1979, Saskatchewan Geological Survey, Saskatchewan Department of Mineral Resources, Miscellaneous Report 79-10, p Lorsong, J.A. (1980): Geometry of nearshore sandbodies in the Upper Mannville Group, Celtic Field, Saskatchewan; in Lloydminster and Beyond, Beck, L.S., Christopher, J.E. and Kent, D.M. (eds.), Saskatchewan Geological Society, Special Publication No. 5, p MacEachern, J.A. (1984): Paleoenvironmental interpretation of the Lower Cretaceous Waseca Formation, upper Mannville Group; in Oil and Gas in Saskatchewan, Lorsong, J.A. and Wilson, M.A. (eds.), Saskatchewan Geological Society, Special Publication No. 7, p MacEachern, J.A. and Bann, K.L. (2008): The role of ichnology in refining shallow marine facies models; in Recent Advances in Models of Siliciclastic Shallow-Marine Stratigraphy, Hampson, G.J., Steel, R.J., Burgess, P.M. and Dalrymple, R.W (eds.), SEPM Special Publication No. 90, p Morshedian, A., MacEachern, J.A. and Dashtgard, S.E. (2012): Stratigraphic framework for the Lower Cretaceous Upper Mannville Group (Sparky, Waseca, and McLaren alloformations) in the Lloydminster area, west-central Saskatchewan; in Summary of Investigations 2011, Volume 1, Saskatchewan Geological Survey, Saskatchewan Ministry of Energy and Resources, Miscellaneous Report , Paper A-3, 17p. Pemberton, S.G., Spila, M., Pulham, A.J., Saunders, T., MacEachern, J.A., Robbins, D. and Sinclair, I.K. (2001): Ichnology and sedimentology of shallow to marginal marine systems; Geological Association of Canada, Short Course Volume 15, 343p. Saskatchewan Geological Survey 19 Summary of Investigations 2017, Volume 1

20 Putnam, P.E. (1980): Fluvial deposition within the Upper Mannville of west-central Saskatchewan: stratigraphic implications; in Lloydminster and Beyond, Beck, L.S., Christopher, J.E. and Kent, D.M. (eds.), Saskatchewan Geological Society, Special Publication No. 5, p Putnam, P.E. (1982): Aspects of the petroleum geology of the Lloydminster heavy oil fields, Alberta and Saskatchewan; Bulletin of Canadian Petroleum Geology, v.30, no.2, p Saskatchewan Ministry of the Economy (2014): Stratigraphic Correlation Chart; Saskatchewan Ministry of the Economy, URL [accessed 1 November 2017]. Van Hulten, F.F.N. (1984): Petroleum geology of Pikes Peak heavy oil field, Waseca Formation, Lower Cretaceous, Saskatchewan; in The Mesozoic of Middle North America: A Selection of Papers on the Symposium on the Mesozoic of Middle North America, Calgary, Alberta, Canada, Canadian Society of Petroleum Geologists, Memoir 9, p Vigrass, L.W. (1977): Trapping of oil at intra-mannville (Lower Cretaceous) disconformity in Lloydminster area, Alberta and Saskatchewan; AAPG Bulletin, v.61, p Saskatchewan Geological Survey 20 Summary of Investigations 2017, Volume 1

21 Figure 6 Southwest to northeast (A-A ) stratigraphic cross-section of the channel reservoir facies (highlighted in brown), correlated using gamma ray and density porosity logs (see Figures 1 and 5 for location of cross-section). Note the low blocky gamma ray signal within the channel. Abbreviations: GR = gamma ray, API = American Petroleum Institute. Figure 9 South to north (B B ) stratigraphic cross-section of the Lower Waseca reservoir facies (highlighted in blue), correlated based on gamma ray and density porosity logs (see Figures 1 and 8 for location of cross-section). Abbreviations: GR = gamma ray, API = American Petroleum Institute. Saskatchewan Geological Survey 21 Summary of Investigations 2017, Volume 1