Browsing by Author "Finley, Robert J."

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A Feasibility Study for Mapping Abandoned Coal Mining Areas in Young County, Texas
(1979) Finley, Robert J.; Hupp, William H.
A total of 276 sites of possible bituminous coal mining were located within Young County, Texas, using black-and-white aerial photography at a scale of 1:20,000. More than 80 percent of these sites are less than 10 acres in size; 14 sites are 40 acres or more in size. Lack of vegetation, disturbed land surfaces, and evidence of active erosion characterize these sites. Forty-five sites are either directly adjacent to natural streams or show distinct runoff channels entering natural streams. Historical mining records were utilized where available, but no field confirmation of sites was included as part of this feasibility study.
A Preliminary Assessment of High Resistivity Cap Rock Shale in the Frio Formation of the Texas Gulf Coast
(1982) Finley, Robert J.
The mapping of high resistivity cap rock shales in the Frio Formation along the Texas Gulf Coast reveals variations in thickness and distribution between the upper and lower regions. Thinner cap rock is observed in the upper Texas Gulf Coast, while thicker and more extensive cap rock is present in the lower Texas Gulf Coast. This variation correlates with increases in maximum shale resistivity, the presence of unstable minerals such as volcanic rock fragments and detrital carbonate grains, and authigenic cementation, all of which are more pronounced in areas with thicker cap rock in the lower Gulf Coast. However, the distribution of cap rock in two major Frio deltaic depocenters does not show clear similarity. Facies analysis of regional cross sections in the lower Texas Gulf Coast, particularly in the Sarita East field of Kenedy County, indicates the preferential development of cap rock in the delta-front/slope facies of the Norias delta system. The sand content within the cap rock interval varies, suggesting that sands within the cap rock may serve as fluid conduits during mineralization processes. Cap rock is less commonly developed in the shale-rich prodelta and distal delta-front facies. While high resistivity cap rock shales have been attributed to authigenic calcite cementation, conclusive evidence for this origin is lacking. Preliminary mineralogic analyses of well cuttings have not provided satisfactory results, highlighting the need for core analysis through cap rock and non-cap rock intervals to determine mineralogic variability and accurately assess any mineralogic control over the high resistivity log response. Further investigation is necessary to better understand the origin and characteristics of high resistivity cap rock shales in the Frio Formation.
An Assessment of the Natural Gas Resource Base of the United States
(1988) Fisher, W. L. (William Lawrence), 1932-; Finley, Robert J.; Seni, Steven J.; Ruppel, Stephen C.; White, William Allen, 1939-; Ayers, Jr., W. B.; Dutton, Shirley P.
The distribution of natural gas in the United States comprises proved reserves in known reservoirs, inferred reserves, undeveloped resources within these reservoirs, and undiscovered resources. Beyond proved reserves, all volumes of future natural gas supply are estimates based on information derived from past and current experience in gas production and reservoir development. Even proved reserves are subject to periodic revision. This assessment begins with an understanding of major components of the natural gas supply derived from existing resource estimates that use established methodologies. In addition to historically defined elements of the resource base, a new component—reserve growth in heterogeneous reservoirs—is quantified in this study. Resource assessments proceed in their planning and compilation from reasonably well-known quantities (proved reserves) to increasingly less well-known quantities (undiscovered resources). Furthermore, natural gas reservoirs termed unconventional are typically given separate consideration and include gas in low-permeability reservoirs, gas in shale formations such as the Devonian of the Eastern U.S., and coalbed methane resources. This approach has been followed in this assessment. Special note was made of Alaskan gas reserves as they are significant and proven, but transportation for North Slope gas to the Lower 48 states is lacking.
Analysis of Low-Permability Gas Sands Suitable for Future Research Programs
(1982) Finley, Robert J.; Han, Jong H.
Research on tight gas sands has traditionally focused on lenticular sands, but blanket-geometry sands, deposited by different processes, present distinct external and internal reservoir geometries requiring unique exploration and production techniques. To ensure the applicability of research findings across various reservoirs, a survey was conducted with a focus on elastic depositional systems and the potential transferability of results between different stratigraphic units. Based on the survey results, five stratigraphic units were selected for further study, and data collection efforts were initiated during the contract period. A comprehensive work plan was developed for the analysis of these units, which includes the preparation of geologic cross sections and maps, review of productive areas, resource analysis, and documentation of findings. The five selected units for study are the Travis Peak Formation, the Corcoran and Cozzette Sandstones, the Mancos "B" interval of the Mancos Shale, the upper Almond Formation, and the Frontier Formation. Data collection efforts have yielded a significant number of well logs from Colorado and Wyoming, with additional logs identified from Bureau files for the Travis Peak Formation. Wells suitable for cross-sectional analysis have been identified for the Travis Peak and Corcoran/Cozzette trends, and initial cross sections have been prepared for the latter trend. These efforts aim to enhance understanding and exploration potential of blanket-geometry tight gas sand reservoirs.
Analysis of Negative Revisions to Natural Gas Reserves in Texas
(1984) Garrett, C. M., Jr.; Hocott, Claude R.; Finley, Robert J.
Early problems in overestimating effective porosity in some deep Delaware Basin carbonate reservoirs in the Permian Basin, particularly in District 8, resulted in noticeable negative revisions once these issues were resolved. However, the net negative volume of revisions for the Permian Basin (Districts 8, SA, and parts of 7B and 7C) was nearly an order of magnitude less than that for the Gulf Coast Basin. The largest negative revisions of total natural gas reserves were concentrated in the Gulf Coast within Texas Railroad Commission Districts 2, 3, and 4. District 4, with the largest volume of negative revisions, accounted for 56 percent of all negative revisions in Texas for the period 1966-1979. The total for the three districts equaled that of the whole state for the same period. Negative revisions of non-associated gas reserves in Districts 2, 3, and 4 accounted for more than two-thirds of the total gas negative revisions for the entire state from 1966 through 1979. Large negative revisions were mainly due to a combination of interrelated factors. Among these, the original overestimation of natural gas reserves in the Texas Gulf Coast, fueled by optimism from market-related incentives, was significant. These estimates underwent insufficient critical review and reassessment, as supplies greatly exceeded demand. Continued high Reserves to Production (R/P) ratios into the 1960s further delayed reassessment. Technical variables such as water saturation, reservoir heterogeneity, and recovery factors, as well as non-technical variables including economic climate and regulatory controls, were analyzed. Concern should be raised regarding the quality of reserve estimates declared during times of excess supply, as these reserves would not have undergone the test of extended maximum demand. However, there have been more frequent reviews of actual recoverable reserves over the last five years. Continued careful review of technical factors and awareness of the impacts of economic and regulatory environment changes suggest that extensive negative revisions over the next 10 to 20 years can be avoided.
Analysis of Negative Revisions to Natural Gas Reserves in Texas
(1985) Garrett, C. M., Jr.; Hocott, Claude R.; Finley, Robert J.; Galloway, William E.
The role of negative revisions in the large-scale decline in natural gas reserves in Texas during the late 1960s and through the 1970s was examined. Analysis of the factors that contributed to the negative revisions determined that no single element was responsible. However, (1) continued high levels of production, (2) original optimistic estimates of gas in place and recovery factors, (3) market-related factors that encouraged overestimation of reserves, and (4) unusually high reserves-to-production ratios (> 15) that obscured the underlying weakness in reserves combined in the Texas Gulf Coast to drastically reduce booked reserves of natural gas. Negative revisions totaling more than 20 trillion cubic feet during the period were found to have resulted mainly from ambiguities in the degree of reservoir heterogeneity, in calculation of water saturations, and in drive mechanism, along with the overestimation of reserves due to optimism encouraged by market-related incentives. The much-reduced reserves-to-production ratios that now exist, along with continued closer monitoring of technical, economic, and regulatory factors that affect gas reserves, indicate that a return of extensive negative revisions over the next 10 to 20 years is avoidable.
Annotated Bibliography of Techniques for Image Enhancement and Interpretation in Remote Sensing
(1979) Finley, Robert J.; Baumgardner, Jr., Robert W.
The purpose of this annotated bibliography is to provide the user of the Remote Sensing Information Subsystem (RSIS) with brief descriptions of recent research techniques of image enhancement and their applications to specific image interpretation problems. Table 2 of the May 1979 ASVT/RSIS Technical Report entitled "Functional Design Narrative Descriptions" listed digital image processing requirements of the RSIS. The references in this bibliography were chosen because they describe these processing requirements. The format of that table was modified slightly and used as the outline for Section One of this bibliography. The bibliography is not intended to be an exhaustive compilation of all pertinent articles. Such a collection would be outdated as soon as it was printed. It does, however, contain a broad sampling of the recent remote sensing literature. We tried not to include multiple references to the same technique, but some repetition was necessary in order to fully describe some procedures of image enhancement and interpretation.
Assessment of Gas Resources for Secondary Gas Recovery Technology
(1990) Jackson, M. P. A.; Ambrose, William A.; Finley, Robert J.
Unrecovered gas resources available through existing technology can be a significant source of reserve additions in maturely explored petroleum provinces. In this study, nonassociated and associated Texas reservoirs were analyzed for gas reserve growth potential. In the nonassociated fluvial Frio Brooks reservoir, infill drilling from 640 to 320 acres per well can potentially increase reserves by 15.7 percent of estimated ultimate recovery. Gas reserve additions may result from improved contact with isolated or partially isolated sandstones that are not effectively drained by conventional development practices. An additional 14.4 billion cubic feet (Bcf) of gas resources can be potentially recovered by strategic infill drilling down to 10-acre spacing in the Grayburg reservoirs of Dune field, one of many mature West Texas fields located on the Central Basin Platform. Infill wells strategically drilled in the Dune field grainstone facies are projected to be most cost-efficient and productive. Recoverable associated gas in selected plays is estimated to be from 3.4 trillion cubic feet (Tcf) to 5.8 Tcf. The greatest recovery potential for associated gas reserve growth in Texas is in carbonate reservoirs with complex facies architecture in the Permian Basin. Geologically based infill wells in areas of greatest reservoir heterogeneity can recover much of this unproduced gas resource.
Comparative Engineering Field Studies and Gas Resources of the Travis Peak Formation, East Texas Basin
(1986) Lin, Zsay-Shing; Finley, Robert J.
Data from eight fields producing from the Travis Peak Formation in the eastern East Texas Basin were used to define key engineering parameters for each field and to develop resource-reserve estimates. Field-average porosities range from 8 to 11 percent, and the median permeability for 191 wells is 0.088 md; field-average permeability ranges from 0.006 to 0.1 md. Gas productivity generally increases from south to north across the area studied with changes in the reservoir drive mechanism. Gas in place in the Travis Peak of the East Texas Basin is estimated to be 19.5 Tcf, assuming 12 percent of the area of the basin is ultimately productive.
Consolidation of Geologic Studies of Geopressured-Geothermal Resources in Texas
(1983) Morton, Robert A.; Ewing, T. E.; Kaiser, W. R.; Finley, Robert J.
Detailed structural mapping at several horizons in selected study areas within the Frio growth-fault trend demonstrates a pronounced variability in structural style. At Sarita in South Texas, shale mobilization produced one or more shale ridges, one of which localized a low-angle growth fault trapping a wedge of deltaic sediments. At Corpus Christi, shale mobilization produced a series of large growth faults, shale-cored domed anticlines, and shale-withdrawal basins, which become progressively younger basinward. At Blessing, major growth faults trap sands of the Greta/Calhoun barrier system, having some discrete shale diapirs but little progradation. At Pleasant Bayou, a major early growth-fault system was overprinted by salt tectonics—the intrusion of Danbury Dome and the development of a salt-withdrawal basin. At Port Arthur, low-displacement, long-lived faults formed on a sand-poor shelf margin contemporaneously with broad salt uplifts and basins. Variability in styles can be related to the nature and extent of Frio sedimentation and shelf-margin progradation and to the presence of salt. Structural styles that are conducive to large geothermal reservoirs include blocks between widely spaced growth faults having dip reversal, salt-withdrawal basins, and shale-withdrawal basins. These styles are widespread on the Texas Gulf Coast. However, actually finding a large reservoir depends on demonstrating the existence of sufficient sand having adequate quality to support geopressured geothermal energy production.
Coordination of Geological and Engineering Research in Support of Gulf Coast Co-Production Program
(1985) Finley, Robert J.; Morton, Robert A.
The objective of this investigation was to evaluate the mechanism of secondary gas recovery by co-production in a slightly geopressured watered-out reservoir (Hitchcock N.E. field). This involved making a geological interpretation of the field and defining the reservoir parameters for reservoir engineering and modeling analysis. The excellent reservoir parameters of the Frio 1A1 sandstone are due to its distributary-mouthbar origin. Slight salinity reductions during production may be evidence of contemporaneous shale dewatering. Geochemical data indicate that the hydrocarbons had a deep source and were introduced by very saline brines. Numerical simulation of the Hitchcock N.E. field is being carried out by modeling the physical dimensions of the field, determining reservoir properties, and matching simulated pressures with historical measures. The historical and simulated measures match has not yet been achieved satisfactorily. Hence, no attempt was made to simulate the future performance of the Hitchcock N.E. field. Studies at the Delee No. 1 well show that there are large short-term variations in mud and mud filtrate resistivity while a well is being drilled. Boron concentrations in the Frio 1A1 sandstone are high and must be corrected for when interpreting some types of neutron logs.
Data Collection Plan For Geological Remote Sensing in the Volcanic Terrain of Trans-Pecos Texas, ASVT Test Site 5
(1980) Finley, Robert J.; Baumgardner, Jr., Robert W.
This document describes a ground and aircraft data collection plan to be carried out as part of the Texas Applications System Verification and Transfer (ASVT) Project, which is a joint effort of the Texas Natural Resources Information System (TNRIS) Task Force and the National Aeronautics and Space Administration (NASA). The Texas Department of Water Resources/TNRIS has contracted with the Bureau of Economic Geology for the preparation of this Data Collection Plan (DCP), to be initially implemented during the period June-August 1980 as described herein. This DCP applies to a test site in the Trans-Pecos region of Texas, one of five designated test sites within the state. Previously, a ground data collection plan had been prepared for the coastal test site (Finley, 1978), and a plan is in preparation for the High Plains test site.
Data Collection Plan For Remote Sensing in the Panhandle of Texas, ASVT Test Site 2
(1980) Finley, Robert J.; Baumgardner, Jr., Robert W.
This document describes a ground and aircraft data collection plan to be carried out as part of the Texas Applications System Verification and Transfer (ASVT) Project, a joint effort of the Texas Natural Resources Information System (TNRIS) Task Force and the National Aeronautics and Space Administration (NASA). The Texas Department of Water Resources/TNRIS has contracted with the Bureau of Economic Geology for the preparation of this Data Collection Plan (DCP), to be initially implemented during the period June-August 1980 as described herein. This DCP applies to a test site in the Panhandle of Texas (fig. 1), one of five designated test sites within the state. Previously, ground data collection plans were prepared for the coastal test site (Finley, 1978) and the Trans-Pecos test site (Finley and Baumgardner, 1980).
Definition of Optimum Isocls Parameters for RSIS Interactive Data Anaylsis , Texas Coastal Applications Test Site
(1980) Baumgardner, Jr., Robert W.; Finley, Robert J.
Data tapes for a specified window are processed through a program called ISOCLS (Iterative Self-Organizing Clustering). The user supplies several input parameters, including the spectral distance between clusters (DLMIN) and the maximum standard deviation for the values within a cluster (STDMAX). The purpose of this study was to vary these two parameters and analyze the differences in images produced from the same data.
Delineation and Environmental Geologic Evaluation of Abandoned Coal Mines in North Central Texas
(1979) Finley, Robert J.; Caran, S. Christopher; Hupp, William H.
An environmental geologic survey of abandoned bituminous coal mines in North-Central Texas located 140 confirmed and probable mines in 12 counties. Previously, 67 mines were known, although some locations were found to be inaccurate. Present surface conditions at the mine sites have been evaluated relative to the need for possible reclamation. Based on the oldest available (and more recent) 1:20,000 to 1:40,000 scale aerial photography, low-altitude aerial observation, and ground confirmation, mining and subsequent mine abandonment have resulted in five major effects. These are: Devegetation, in part due to leachates from mine spoil. Erosion by gullying, sheetwash, and mass wasting. Increased sedimentation in tanks and streams. Ground surface subsidence. Accumulation of mine spoil, deteriorated equipment, and other refuse. The coals, mined from the 1850s to the 1940s, are in the middle and late Pennsylvanian Strawn, Canyon, and Cisco Groups. Mining was primarily underground by a modified longwall advancing method. A total of 585 acres has been affected by mining, with 142 acres in Young County (13 confirmed mines), 94 acres in Palo Pinto County (16 confirmed mines), and 45 acres in Wise County (15 confirmed mines). The greatest surface effects are evident near Thurber in Erath County and at Strawn in Palo Pinto County, where extensive spoil piles are present. Near Bridgeport in Wise County, shale in the spoil piles has been used in brick-making. Presently there is renewed interest in these bituminous coal resources, and exploration is active.
Extrapolation of Gas Reserve Growth Potential: Development of Examples from Macro Approaches
(1992) Jackson, M. P. A.; Finley, Robert J.
An analysis of infield completions and reserve growth potential was made in Tertiary non-associated gas reservoirs in South Texas. Infield well completions were defined from a concurrent GRI project involving macro-scale prediction of reserve growth. This report validates 78 percent, or 5.6 Tcf, of a high-end infill estimate of 7.2 Tcf for nine stratigraphic units in South Texas. This is a significant resource volume given the historical expectation that natural gas can be efficiently drained with widely spaced wells (1 or 2 per square mile) in conventional reservoirs. Groups of infield completions, or reservoir sections, from Frio, Vicksburg, Wilcox, and Miocene reservoirs were examined using geophysical well logs and production and pressure analyses. Seven reservoir-section types that contributed to the macro reserve growth estimate were evaluated. About 20 percent of the estimate consists of gas volumes extrapolated using consolidated reservoir groups, cycled reservoirs, and reservoirs with invalid data. Additional gas volumes in the estimate were extrapolated from reservoir sections representing rate acceleration. The estimate also includes reservoir volumes from the low-permeability Wilcox Lobo trend, where limited drainage radii lead to expected reserve growth. Volumes that represent within-reservoir reserve growth and volumes that represent shallower- or deeper-pool reservoirs determined not to be in pressure communication with preceding completions in a reservoir section formed most of the macro reserve growth estimate.
Geologic Analysis of Primary and Secondary Tight Gas Sand Objectives, Phase C
(1984) Finley, Robert J.; Dutton, Shirley P.; Lin, Zsay-Shing; Saucier, A. E.; Baumgardner, Jr., Robert W.
Previous assessments of blanket-geometry tight gas sandstones led to the selection of the Travis Peak Formation of the East Texas and North Louisiana Basins and the Corcoran and Cozzette Sandstones of the Piceance Creek Basin as major research objectives. The anticipated outcomes of this study include increased availability of tight gas resources and advancements in technology with high transferability. The work reported here encompasses all aspects of the depositional systems and reservoir geology of these units as fundamental components of resource characterization, with an emphasis on understanding controls on reservoir facies distribution and their relevance to low-permeability reservoir development. Six lithofacies of the Travis Peak (Hosston) Formation in East Texas and North Louisiana have been identified using electric logs. These facies comprise sand-rich fluvial-deltaic, silt-rich delta-front, clay- and carbonate-rich shelf, carbonate reef, and clay-rich open marine facies. The most well-developed facies in the East Texas area are the fluvial-deltaic and delta-front facies. Travis Peak rocks from the Clayton Williams #11 Sam Hughes well, Panola County, Texas, were primarily deposited in a fluvial environment within a coastal plain setting. Porosity and permeability control in the clean sandstones are primarily attributed to quartz overgrowths, chlorite cement, and solid organic matter, with approximately half of the remaining porosity being secondary, resulting from framework grain dissolution. Studies of Travis Peak gas production at Pinehill Southeast and Percy-Wheeler fields indicate an average permeability-thickness product of about 10 md-ft, with a range of 0.7 to 35 md-ft, indicating dry gas reservoirs. Well logs, core, and mud logs from Chapel Hill field in Smith County, Texas, were examined in preparation for a complete cooperative well program in the ARCO #11 Phillips well on the western margin of that field. Field studies of Corcoran-Cozzette Sandstones near Grand Junction, Colorado, suggest that the depositional environments of the Corcoran evolved from marine upper shoreface to non-marine, while the Cozzette sequence evolved from lower to upper shoreface. Porosity and water saturation calculations have been conducted by computer for seven Corcoran and Cozzette depositional units. A comparison of calculated water saturation with core-derived porosity and permeability indicates a fair to very good correlation of reservoir properties with clay content measured by gamma-ray log.
Geologic Anaylsis of Primary and Secondary Tight Gas Sand Objectives Phase A&B
(1983) Finley, Robert J.; Garrett, C. M., Jr.; Han, Jong H.
Finley (1982) listed geologic and engineering characteristics of over 30 blanket-geometry tight gas sandstones in a survey of 16 sedimentary basins. Emphasis was placed on defining elastic depositional systems and on using constituent facies as a method of evaluating the common features of stratigraphic units of different ages in diverse sedimentary and structural settings. Blanket-geometry tight gas sandstones considered suitable for future research by the Gas Research Institute were found to occur primarily within deltaic and barrier-strandplain depositional systems. An assessment of expected transferability of research results (extrapolation potential) was made between stratigraphic units, and more detailed study of six formations was recommended. The Corcoran and Cozzette Sandstones of the Piceance Creek Basin and the Travis Peak Formation of the East Texas Basin and North Louisiana Salt Basin were recommended for research by the Gas Research Institute on blanket-geometry tight gas sandstones, and initial studies of depositional systems were begun. The Corcoran and Cozzette represent the barrier-strandplain system and contain barrier, offshore bar, and associated marginal-marine facies. Detailed studies of the Corcoran-Cozzette in Shire Gulch and Plateau Fields show shoreface sequences common to the lower parts of both units, and bay-lagoon and deltaic facies occur in the upper parts. The Travis Peak Formation represents a deltaic system, having a lower subdivision of progradational deltaic facies, a thick middle subdivision of braided alluvial deposits, and an upper subdivision of marginal marine deposits influenced by marine transgression. Sands greater than 50 ft thick are prominent in the middle subdivision in areas on the west flank of the Sabine Uplift. The Frontier Formation and the upper Almond Formation of the Greater Green River Basin and the Olmos Formation of the Maverick Basin are not recommended for further research, but should be considered when the need arises to test barrier, offshore bar, and possibly deltaic facies outside the two main research areas. The estimated gas resources associated with the Corcoran-Cozzette and the Travis Peak in Texas are 3.7 and 17.3 Tcf respectively. The Mancos "B" of the Piceance Creek Basin is not recommended for any additional research because its unique distribution of lithologies limits its extrapolation to a small group of shelf deposits, some of which have already been investigated. The extrapolation potential of the Travis Peak is largely to itself over a wide area of East Texas and North Louisiana. Extrapolation potential of the Corcoran and Cozzette extends to a large number of stratigraphic units, mostly within the Upper Cretaceous of the Rocky Mountain Region.
Geologic Evaluation of Critical Prodcution Parameters for Coalbed Methane Resources
(1987) Finley, Robert J.
Coalbeds of the United States contain an estimated 200 to 800 Tcf of unconventional gas, much of which is in seams that are unminable or uneconomic (GRID, 1985). Early studies of coalbed methane by the U.S. Bureau of Mines were directed toward degasification in advance of underground coal mining (Rightmire, 1984). The increase in energy prices in the 1970s focused attention on coalbed methane as a potential resource, and subsequently, several hundred wells have been drilled, primarily in the Black Warrior, San Juan, and Piceance Creek Basins. The Gas Research Institute (GRI) has actively supported research aimed at developing the technology for economic production of coalbed methane. At the onset, well completions in coalbed reservoirs were a new and unperfected procedure that required innovative modification of established techniques. Therefore, earlier research efforts were directed toward the engineering problems associated with production, with less emphasis on geologic and hydrologic parameters that control coalbed methane occurrence and producibility. Knowledge of these geologic controls has been found, however, to be important to successful well completions and to the development of regional exploration models.
Geology and Engineering Characteristics of Selected Low-Permability Gas Sands: A Survey
(1982) Finley, Robert J.
Research on tight gas sands has traditionally focused on lenticular sands, but there is growing recognition of the importance of blanket-geometry sands, which are deposited by different systems and have distinct reservoir characteristics. To ensure that research findings are applicable across various reservoir types, this survey emphasizes elastic depositional systems and the potential for extrapolating results between different stratigraphic units. Information was gathered for 16 sedimentary basins, focusing on the general attributes, economic factors, geologic parameters of the basin, and specific geologic and engineering parameters of selected blanket-geometry tight gas sands. These sands are primarily associated with deltaic barrier-strandplain systems and, to a lesser extent, shelf elastic depositional systems. For example, formations like the Travis Peak and Frontier Formations, representing fan delta and deltaic systems, respectively, show high operator interest and good extrapolation potential. Within the Mesaverde Group in basins like the San Juan, Piceance Creek, Uinta, and Greater Green River Basins, several formations exhibit good extrapolation potential, particularly those associated with barrier-strandplain systems. Offshore bars and other minor facies are also present in these systems. Examples include the Cozzette and Corcoran Sandstones, which are of interest to explorationists and merit further study. Among shelf systems, the Mancos "B" Formation and adjacent intervals warrant examination alongside formations like the Cozzette and Corcoran Sandstones to ensure that potential tight gas resources in shelf systems are adequately considered. This comprehensive approach aims to broaden understanding and facilitate effective exploration and development strategies for blanket-geometry tight gas sands.