Predicting Tidal Sand Reservoir Architecture Using Data from Modern ...

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Wood, L. J., 2004, Predicting tidal sand reservoir architecture using data from modern and ancient depositional systems, in Integration of outcrop and modern analogs in reservoir modeling: AAPG Memoir 80, p. 45 – 66.

Predicting Tidal Sand Reservoir Architecture Using Data from Modern and Ancient Depositional Systems Lesli J. Wood Bureau of Economic Geology, John A. and Katherine G. Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, U.S.A.

ABSTRACT

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idal sandbanks make up most reservoir-quality rock volume in hydrocarbon fields characterized by tidally influenced deposits. Predicting the threedimensional architecture and petrophysical character of these elements is critical to a proper assessment of a field’s recoverable hydrocarbon potential. Most of these fields are under development or even in stages of secondary or tertiary recovery that require accurate flow-simulation and resource-distribution models. Modern tidal settings and ancient tidal deposits provide dimensional and architectural data that can significantly reduce our uncertainty in constructing realistic reservoir models of these tidal-bank systems, improve our ability to estimate probability of exploration success, and help us evaluate correlation lengths between subsurface wells and lower-resolution seismic data. Modern tidal banks can be found in many depositional settings, from shallow estuaries to the outer continental shelf. Deep submarine canyons on the outer shelf strongly influence the shelf tidal processes by establishing a geomorphic link between deep-ocean and shallow-ocean currents. These interacting processes, in turn, influence the distribution of tidal banks. Banks that develop in shelf locations are thick, broad, and asymmetric, with linear forms distributed radially around the current or sediment source. Banks that develop in estuaries are thin, narrow, and symmetric, with parabolic forms or bar chains lying parallel to the estuary walls. Ancient tidal banks from the Sego Sandstone (upper Campanian) in eastern Utah show a distinct organization of different dimensions between systems tracts and sequences. Falling-stage tidal bars and ridges are shorter and wider than transgressive tidal bars and ridges, a difference attributed to increased sediment supplies, decreased water depths, and increased energy conditions associated with base-level fall. Cumulative-probability curves provide the format for using modern and ancient systems’ architectural data on tidal-bank dimensions to estimate the probability that certain bank dimensions may occur in ancient deposits. Cumulative-probability curves show that the P50 for worldwide tidal-bank length is 12,000 m, width is 1600 m, and height is 9.2 m. These curves provide the means to assess the probability of correlation

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between wells of varying distances as well as the likelihood of resolving tidal banks in seismic data at varying resolutions.

INTRODUCTION Tidally influenced shoreline and deltaic deposits form some of the largest and most architecturally complicated hydrocarbon fields in the world (Verdier et al., 1980; Carneiro de Castro, 1983; Marjanac and Steel, 1997; Higley, 1994; Ambrose et al., 1995; White et al., 1995; White and Barton, 1999; Martinius et al., 2000). Despite the highly prolific nature of reservoirs in these types of deposits, few well-documented, ancient subsurface examples exist. In addition, although 8 of the 12 largest deltas in the modern world either are tide dominated or show strong tidal influence (Middleton, 1991, after Milliman and Meade, 1983), surprisingly little attention has been paid to characterizing tidally influenced deltas or shorelines in the modern record. Hydrocarbons are notoriously difficult to produce from reservoirs in fluvial and deltaic deposits, leaving behind, on average, 60% of the resources in place (Tyler and Finley, 1991). Recent advances in 3-D computer modeling of flow through subsurface reservoirs, however, have increased engineers’ understanding of how to design successful secondary recovery programs to enhance production, yet building rigorous 3-D geologic models requires knowledge of the geometries and material properties of reservoir bodies (Weiler, 1988; Conreaux et al., 1998; Lu et al., 1998). Improved 3-D fluid-flow models of heterogeneous and complex tidally influenced reservoirs are critical for proper development planning and secondary recovery design and implementation. Much of the uncertainty in flow simulations is related to uncertainty about the geologic model. To increase our ability to construct geologically realistic models of tidal sand reservoirs, we must improve our ability to predict the architecture of tidal bars/ridges, their facies, distribution, and orientation. In addition, to improve our ability to predict the occurrence and maturity of tidal banks in subsurface data, we must assess the effect that changing conditions of sediment supply, water depth, and energy conditions have on their formation. Two different scales of tidal shelf barforms described in literature are commonly lumped together under the term ‘‘tidal sand ridge’’ or ‘‘tidal sandbank’’ (Dyer and Huntley, 1999). We will refer to these two types as tidal sand bars and tidal sand ridges. Tidal sand bars are single-cycle, upward-coarsening sand features, typically bioturbated in their upper meter, with dimensions on the order of less than 4 m thick, less than 1500 m wide, and less than 10 km long. Mallet et al. (2000)

described a single, elongate tidal bar at the mouth of the Gironde Estuary in France, noting it to be approximately 1 m high, asymmetric with an orientation approximately 168 anticlockwise to the main channel orientation and tidal-flow direction. Composed of small, medium, and large subaqueous sandy dunes, this feature is an excellent example of a tidal sand bar. In contrast, numerous authors have documented much larger features— ‘‘tidal sand ridges’’ (Off, 1963; Amos and King, 1984). Study of modern tidal sand ridges in the North Sea has shown them to be composed of several upwardcoarsening successions of fine to medium, well-sorted sand with small to large multidirectional cross-stratification (Davis and Balson, 1992). Each of these successions represents the architectural building blocks of tidal sand ridges. Workers commonly do not discriminate between bars and ridges, although the quantitative morphology data contained herein will show clearly distinct size differences in these features. For purposes of our general discussion, we will refer to both bars and ridges as tidal sands, unless specifically discussing one or the other.

Objectives This paper synthesizes a large data set from literature on the dimensions and distribution of siliciclastic tidal sands and examines the utility of that data set for predicting trends in sand-body dimension, orientation, and distribution. In addition, this paper presents a comprehensive data set on the dimensions of tidal sand bars and tidal sand ridges from ancient tidal-deltaic and estuarine deposits of the Sego Sandstone in the Book Cliffs area of eastern Utah. Relationships between bar/ ridge dimensions and systems tracts (cf. Van Wagoner et al., 1988) are examined, and an approach is presented for using cumulative-probability curves (CPC) to assess the probability of occurrence for tidal-bar and -ridge forms of certain dimensions that can be used to predict correlation lengths between wells.

MODERN TIDAL SAND SYSTEMS Tidal sands were described by Hulscher et al. (1993) as being relatively stable, having characteristic wavelengths of hundreds of times the undisturbed water depth and crests oriented slightly counterclockwise (angles between 5 and 308) with respect to the principal

Predicting Tidal Sand Reservoir Architecture Using Data from Modern and Ancient Depositional Systems

tidal-current direction. Their heights range between 4 and 10 m, but some have been documented with as much relief as 30 m (see Off, 1963). They can be extremely long (several tens of kilometers) and may lie either tightly clustered or be separated by well over 10 km distance. Amos and King (1984) defined tidal sand ridges as having length/width ratios exceeding 40. For a more comprehensive treatment of the subject of modern tidal sands formation, see Dyer and Huntley (1999). Tidal sands can be found worldwide in many tidal coastal settings (Figure 1). Off (1963) compiled a comprehensive, and to this date unequaled, database from bathymetric charts of what he referred to as modern ‘‘tidal-current ridge’’ geometries by measuring dimensions of some 225 tidal sand ridges in 4 different geomorphic settings at 30 worldwide localities. For purposes of this review, additional measurements have been added to this compilation from recent work by other researchers; however, most of the modern systems data discussed in this manuscript were compiled by Off (1963). Sand ridges were measured by Off (1963) from bathymetric charts of varying scales, yet his examination of variously detailed charts yielded no variation in the accuracy of his measurement. Spacing was computed by measuring the width of a ‘‘set’’ of ridges along a line drawn approximately perpendicular to the ridges at their midpoint, then dividing this figure by the number of spaces between the ridges. Height was taken as an

average of the relief of each ridge above the adjacent sea floor, and length was measured at the long axis. Width was measured at the maximum perpendicular to the long axis. Off (1963) often reported ranges of heights, widths, and lengths for a suite of ridges. In these instances, to arrive at a single, representative median for the cluster of tidal-ridge or tidal-bar elements, the numbers were averaged. A data set of representative element dimensions from 30 locations worldwide (Figure 1) is the result.

Importance of Geographic Setting in Tidal Sand Formation Mean sea level and tidal and sedimentological conditions determine tidal sand bar/ridge orientation, spacing, and lithologic composition (Huthnance, 1982). Numerous authors have noted the relationship between coastal and offshore morphology (for a review, see Dyer and Huntley, 1999). In a study of five areas off the eastern United States, McBride and Moslow (1991) showed that a coupling could be established between certain coastal morphologies and shelf sand bodies, noting that the same major physical processes responsible for shaping and controlling coastal geomorphology also dictate the morphology and type of sand body on the adjacent shelf floor. Off (1963) noted that tidal ridges occur in four geographic settings: open oceans, river mouths, heads of bays, and tidal coasts (Figure 2).

FIGURE 1. World map of tidal shelves and localities of tidal sandbank occurrence used by Off (1963).

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FIGURE 2. Examples of the four geomorphic classes for tidal sandbanks as defined by Off (1963): (A) river-mouth example showing the morphology of the mouth of the Delaware River, U.S.A.; (B) open-ocean example showing the Tongue of the Ocean area in the Bahamas; (C) head-of-bays example showing the Ganges Delta, India; and (D) tidalcoast example showing the coast of west Africa near the Senegal and Guinea-Bissau border. FA = fathoms.

Predicting Tidal Sand Reservoir Architecture Using Data from Modern and Ancient Depositional Systems

Examining Off’s data in the context of his defined geographic locations of occurrence should yield a tighter grouping among architectural elements because those deposits under similar geographic conditions should exhibit similar characteristics. Several authors since Off have proposed tidal sand classification systems, including Swift (1975), Amos and King (1984), Pattiaratchi and Collins (1987), and most recently, Dyer and Huntley (1999). However, Off’s data will not be reclassified into any more recent classification scheme herein because details are sparse regarding the original localities. Three of the four geographic tidal-system classes defined by Off (1963) show little difference among them in average tidal velocity. All have average velocities of 0.6 – 0.75 m/s. The exception is the rivermouth class, which shows averages of closer to 1 – 1.25 m/s (Figure 3). Rivers, such as the Amazon in Brazil, are known to have tidal velocities of 2.5 m/s or more.

River Mouths Well-formed tidal bars and ridges are commonly present at the mouths of rivers, such as the Amazon and other South American rivers, as well as many Alaskan and eastern United States rivers. The Bay of the Delaware River, United States, provides an excellent example of the river-mouth setting in which tidal sands are deposited (Figure 1, location 21; Figure 2A). The Delaware River empties into the Atlantic Ocean off the coasts of Delaware and Maryland. Twelve tidal sand forms are mappable that parallel the sides of this bay, a distribution typical of tidal sands found in the confines of the valley/bay mouth. The size and distribution of these sands varies from long, narrow, high relief and tightly spaced (20 km long, 1.6 km wide, 12 m high, and 3.2 km apart) to short, narrow, low relief and very tightly spaced (5.6 km long, 0.9 km wide, 4.6 m high, and 1.3 km apart). The origin of these tidal sand forms has been attributed to evolving tidal processes associated with the last rise in sea level (Weil et al., 1973; Kraft et al., 1974).

Open Ocean Tidal currents interact with open-ocean processes in many shallow shelf areas of the world to form tidal sand bars and ridges. An excellent example of openocean, tidal-ridge development is found in the southern end of the North Sea off the regions known as The Wash and The Fens located off east-central Great Britain (Figure 1, location 16; Figure 2B). In this region, tidal currents average 75 cm/s on the open shelf. Off (1963) measured numerous sand ridges scattered about in the vicinity of The Wash. Many of these features were imaged using echo-sound technology in the late 1950s (Stride, 1959a, b) and are described as being topped with

FIGURE 3. Graph of tidal velocity for several localities around the world classed according to Off’s (1963) locality classes for tidal-ridge deposition. There is minor variation in average tidal velocity among locality types except in river-mouth settings, where average tidal velocity nearly doubles, in some localities reaching as much as 5 m/s.

sand waves. Tidal sand ridges in the area are some of the tallest in the world, being as much as 24 m high and averaging more than 44 km in length. These ridges are also some of the narrowest of the open-ocean examples, averaging 1200 m wide. Although they seem widely spaced (9 km), their height-to-spacing ratio is right at the median for open-ocean tidal sand ridge systems. Few to no rivers drain the upland areas surrounding The Wash, and it is believed that the sands in the offshore tidal ridges are reworked from previously deposited glacial sands (Off, 1963).

Heads of Bays Tidal ridges are profusely developed at the heads of bays, such as the Gulf of Korea in South Korea, the head of the Arabian Gulf in the Middle East, and as shown in Figure 1, the head of the Bay of Bengal, near the mouth of India’s Ganges River (Figure 1, location 7; Figure 2C). This location also is the site of the world’s aerially largest delta, the Ganges Delta, whose delta plain is some 350 km (220 mi) wide. Ridge orientation in this locale is influenced by a submarine canyon that impinges on the coast and significantly influences the shape and orientation of offshore tidal ridges that curve toward the canyon (Off, 1963). More than 20 ridges were measured by Off at this locale. Their dimensions average 32 km in length, 3.6 km in width, and 8.2 km in height. They are spaced approximately 11.6 km apart, more widely than ridges found at similar water depths in other localities. Off (1963) attributed this wide spacing to the heavy silt and mud content of the Ganges River,

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which promoted bar aggradation instead of progradation and widening.

Tidal Coasts Tidal coasts are extensively developed around the world where large gulfs or inlets are absent but large tidal ranges and strong tidal currents are present. In many areas, such as the west coast of Africa near the Senegal and Guinea-Bissau border (Figure 1, location 8; Figure 2D), there is no specific coastline orientation that enhances tidal currents. The countries of Senegal and Guinea have low-lying coastal plains with many rivers and some broad, swampy estuaries. Deep Atlantic Ocean currents concentrate high tidal energy on the shelf areas. Numerous tidal sand ridges are found offshore that average 24 km in length, 2 km in width, 7.2 km in height, and are spaced approximately 6.7 km apart.

Dimensional Trends in Modern Tidal Sandbanks The width of modern tidal sand ridges that had been documented by Off (1963) was plotted against the length, regardless of geographic class. This process yielded a widely scattered but somewhat simple linear relationship between the two parameters (Figure 4A). Most tidal sandbanks are less than 30 km long and less than 3 km wide, with less than 15 m of relief (not shown in Figure 4A). However, several tidal sandbanks have lengths of greater than 35 km, while maintaining widths and heights that are in line with the norm for the overall data set. Grouping the data according to geomorphic setting shows that some of these longer elements are found proximal to river-mouth or headof-bay settings (Figure 4B). These unusually long features may represent bar/ridge chains (Dalrymple and Rhodes, 1995) instead of individual bars or ridges, a fact that would explain why they appear abnormally long for their normal height and width. Ratios of width/ length increase as one moves from river mouth to heads of bays to open oceans and finally to tidal coastal settings. Off (1963) focused on the relationship between ridge height and ridge spacing, thinking there was a constant ratio between the two. Allen (1968) found that Off’s ridge heights increased roughly as (spacing)1/2. Huthance’s (1982) model predicted that ridge spacing was roughly equivalent to 250
mean water depth. Huthance also examined Off’s data and acknowledged the relationship between ridge height and spacing (ridge height/spacing = 0.0038 ± 0.0020 [standard deviation]). Huthnance also noted, however, that much scatter existed in the data. He attributed this scatter to the

FIGURE 4. (A) Graph of tidal-ridge length versus width undifferentiated by geographic setting, showing an observable relationship between length and width of tidal ridges. (B) Graph of tidal-ridge length versus width differentiated by geographic setting.

present-day high interglacial water depths and the insufficient sand in deep water that was necessary for ridges to build to sea level. Reexamined in the context of coastal type, the ridge height/spacing ratio decreases slightly from open oceans (average 0.0034) to river mouths (average 0.0032), to heads of bays (average 0.0030), and finally, to tidal coasts (average 0.0026). Considerably more scatter exists in the spacing of ridges in river-mouth and head-of-bay systems than in openocean settings (Figure 5). Separation distances between ridges in river-mouth settings can range from less than 1 km to nearly 10 km. In comparison, open-ocean ridges tend to form between 2 and 5 km apart. Excluding a few specific anomalous localities, tidal coasts also tend to

Predicting Tidal Sand Reservoir Architecture Using Data from Modern and Ancient Depositional Systems

show consistently more tightly packed tidal ridges that tend to be spaced 1–4 km apart. The inconsistency in ridge separation distances associated with river-mouth and head-of-bay systems is to be expected where ebband-flow tidal processes are active in rapidly migrating channels (Dalrymple and Rhodes, 1995). Spacings are more consistent in open-ocean or tidal-coast settings, where currents and ebb-and-flow channels are less subjected to seasonal continental processes. Even when examined in the context of coastal type, measures of tidal-ridge length/height show a large scatter and no discernable trend associated with coastal type. However, measures of tidal-ridge width/height reveal much more tightly clustered relationships (Figure 6). The range of width/height ratios increases from open ocean to river mouth, to head of bay, and to tidalcoast settings. Although a greater density of tidal sandbanks commonly are found along tidal coasts, they also tend to show a larger range of ridge widths than areas such as river mouths. Some of the scatter in width/ height is because of the inclusion in the data set of a large number of very low-relief (537 m) to be penetrated by Cumulative-probboth wells. (B) Cumulative-probability plot showing the probability of occurrence of ability curves of data specific tidal-bar heights based on data from the Sego Sandstone, eastern Utah. from ridge thickness worldwide show a P50 of 1600 m. These results 2 m (P10 = 2 m). In the Federal 2-34 well (Figure 14), the indicate that less than 10% probability exists for three stacked, upward-coarsening parasequences seen finding ridges larger than 3350 m or smaller than 550 in sequence 2 are each greater than 10-m-thick tidal m. Some of the widest ridges are found in heads of ridges composed of several stacked, individual, tidalbays, possibly a function of abundant sediment supbar architectural elements. A similar stack of amalgaply allowing for bars to laterally accrete, but a lower mated tidal bars is observed in sequence 2, found in the wave base limiting the aggradation of tidal bars. This Federal 33-16 and the Hancock Federal No. 2 wells (Figure 13). Tidal-bar and -ridge length data from the Sego Sandstone were limited because of the limited dip orientation of the outcrop exposures. Off’s (1963) data set of tidal-ridge lengths was therefore plotted on a CPC, and separation distances from subsurface wells adjacent to the Sego outcrop were plotted on the same graph (Figure 18A). The worldwide tidal-ridge sizes were used as a guide to assess the probability of tidal sands being correlatable between FIGURE 18. (A) Cumulative-probability plot showing the probability of occurrence of the subsurface wells. specific tidal-ridge lengths based on data from a worldwide data set of modern tidal-ridge Cumulative-probability lengths. Distance between two dip-oriented wells in the Sego are shown to illustrate a 15% curves show 80% of the probability that a 2000-m-long tidal bar/ridge in the Sego would not reach between the wells. (B) Cumulative-probability plot showing the probability of occurrence of specific tidal-ridge worldwide length data width based on data from a worldwide data set of modern tidal-ridge widths. Plot shows occurring between 2 (P10) the specific occurrences of tidal-ridge widths from the Sego Sandstone for comparison. and 42 km (P90) (Figure (C) Cumulative-probability plot showing the probability of occurrence of specific tidal18A). This broad range ridge height based on data from a worldwide data set of modern tidal-ridge height. Plot shows of lengths is skewed to- the specific occurrence of tidal-ridge heights from the Sego Sandstone for comparison. ward the low end, with (D) Cumulative-probability plot showing the probability of occurrence of specific tidal-ridge P50 = 12 km and P80 = spacing based on data from a worldwide data set of modern tidal-ridge spacings.

Predicting Tidal Sand Reservoir Architecture Using Data from Modern and Ancient Depositional Systems

observation also may explain why tidal ridges of the Sego, deposited in a shallow epicontinental seaway, are wider than the P50 worldwide tidal-bar width (Figure 18B) and are, on average, shorter than the worldwide P50 tidal-bar height (Figure 18B). Cumulative-probability curves of worldwide tidalridge thickness show a P50 = 9.2 m, indicating a less than 10% probability of finding tidal ridges greater than 15.6 m thick or less than 4 m thick (Figure 18C). Because tidal ridges cannot be smaller than their own architectural elements, tidal bars, 4 m (which is very close to the P50 thickness for tidal bars defined in the Sego Sandstone) most likely represents a lower limit for tidal-ridge thickness. The thickness of stacked, tidalridge parasequences found in the Sego Sandstone well logs is commonly 8 – 9 m, reflective of the worldwide P50 for ridge thickness. A CPC of worldwide tidal-ridge spacing shows a P50 of 3100 m, with few ridges spaced more closely than 450 m (P10 = 450 m) and few spaced wider than 8000 m (P90 = 8000) (Figure 18D). Off (1963) and others have suggested a relationship between ridge thickness and spacing. However, thicknesses appear to be normally distributed, whereas spacing appears not to be normally distributed. The actual accuracy of correlation between the two parameters has been questioned. Although we know that current speed and water depth control ridge spacing, there is no clear pattern in the occurrence of widely spaced ridges. They exist in every tidal setting in the world and compose the statistical ‘‘tail’’ of the data.

of certain dimensions will occur and to assess the correlation length of tidal-bar and -ridge reservoir elements in the subsurface. Several specific conclusions were arrived at in the course of this research: 







CONCLUSIONS Outcrop and modern tidal sandbank data provide quantitative dimensional and spatial distribution information that can be used to significantly improve our estimates of reservoir dimensions in tidally influenced, hydrocarbon-producing reservoirs around the world. These data provide insights into how tidal-bank geometries develop in response to changing conditions of water depth, sediment supply and type, and current intensity and modality. These observations, and the resulting model for tidal-bank development, are helpful in predicting differences in the architecture of tidal banks developing under conditions of changing relative shoreline. Such models also help explain the apparent difference in the architecture of tidal banks seen in different systems tracts and sequences of the Sego Sandstone (upper Campanian), Utah. Cumulativeprobability curves constructed using both modern data from tidal settings around the world and ancient data sets from the Utah Sego outcrops can be used to predict the probability that tidal bars and ridges

Modern tidal-system settings, classified into open oceans, heads of bays, river mouths, and tidal coasts each have their own distinct sets of conditions (sediment type and amount, water depth, tidal velocity and magnitude, and nuclei type and occurrence) that influence the dimensions and distributions of individual tidal bars and ridges. Modern tidal ridges worldwide exhibit a P50 height of 9.2 m, length of 12 km, width of 1600 m, and spacing of 3100 m. Tidal ridges in the Sego appear shorter (P50 width = 6 m) and slightly wider (P50 width = 3100 m). This difference is interpreted to be a function of shallower water depths and slower tidal-current velocities and higher sediment supplies in this progradational portion of the western interior Cretaceous seaway. Such conditions are also typical in modern heads of bays, such as the Bay of Bengal, India, an area that exhibits tidal ridges of a geometry similar to that of the Sego Sandstone in Utah. The lower limit for modern tidal-ridge thickness worldwide (P10 height = 4 m) is very close to the average tidal-bar thickness in the Sego (P50 = 3.5 m) [S/B P10?], reflecting the dictate that a tidal ridge cannot be larger than the tidal-bar elements that make it up. Spatial distribution of tidal bars and ridges varies temporally within a cycle of shoreline change as a function of the changing conditions when water depths decrease over the shelf and sediment supplies increase and when water depths increase and sediment supply begins to decrease. Falling-stage tidal bars and ridges are shorter and wider than transgressive tidal bars and ridges.

ACKNOWLEDGMENTS This research was initiated as part of the Bureau of Economic Geology’s Clastic Reservoirs Group, which included myself and project scientists Shirley P. Dutton, Chris D. White, and Brian Willis. Amoco Production, ARCO Oil and Gas, British Petroleum International, Chevron Petroleum Technology, Exxon Production, Intevep, Japan National Oil, Maxus Exploration, Oryx Energy, Saga Petroleum, and Statoil funded the research. Sharon Gabel, Matt Uliana, and Mulegheta Feseha assisted with data collection in the field, and Matt Uliana and Yugong Gao helped process the field

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data. Ramero Amaya and Dallas Dunlap helped load and quality control the well-log data, and Jana Robinson drafted the final figure. John C. Van Wagoner and Mark Kirschbaum generously provided advice and insights into the Sego deposition throughout the course of this project. Shirley Dutton provided early reviews that added significantly to the quality of the submission. Marjorie Levy, Bill Morgan, and Paul Harris provided comments and suggestions that immensely improved the quality of the final manuscript.

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Predicting Tidal Sand Reservoir Architecture Using Data from Modern and Ancient Depositional Systems

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