Pub Date : 2023-12-01DOI: 10.31582/rmag.mg.60.3.189
Bruce A. Black
Black Exploration, LLC drilled a wildcat oil and gas test on a large structure on the Zia Pueblo in early 2023. The primary objectives were oil and gas. However, helium potential was also recognized as a possible secondary objective. This large structure sits adjacent to some of the largest reported air corrected mantle, He and CO2 degassing carbonic and geothermal springs in the Rocky Mountain region. The prospect overlies a classic Synthetic Overlapping Transfer Zone between the northern Albuquerque Basin and the southern Espanola Basin in the Rio Grande rift in Northern New Mexico. Recognition of possible deep crustal and upper mantel faulting as well as surface geologic mapping, gravity, seismic and geo-microbial techniques helped delineated the prospect. A possible explanation for why high mantle derived helium is concentrated in this area is the intersection of the ancient Jemez Lineament and the more recent Rio Grande rift. This wildcat has now discovered helium and white hydrogen in the Abo formation. If economically productive the well will be the first helium discovery in the Rio Grande Rift. This could open the rift and its sub basins into a large, new oil, gas and helium and hydrogen producing province.
{"title":"An Oil and Gas Play Turns Into a Prime Helium Prospect","authors":"Bruce A. Black","doi":"10.31582/rmag.mg.60.3.189","DOIUrl":"https://doi.org/10.31582/rmag.mg.60.3.189","url":null,"abstract":"Black Exploration, LLC drilled a wildcat oil and gas test on a large structure on the Zia Pueblo in early 2023. The primary objectives were oil and gas. However, helium potential was also recognized as a possible secondary objective. This large structure sits adjacent to some of the largest reported air corrected mantle, He and CO2 degassing carbonic and geothermal springs in the Rocky Mountain region. The prospect overlies a classic Synthetic Overlapping Transfer Zone between the northern Albuquerque Basin and the southern Espanola Basin in the Rio Grande rift in Northern New Mexico. Recognition of possible deep crustal and upper mantel faulting as well as surface geologic mapping, gravity, seismic and geo-microbial techniques helped delineated the prospect. A possible explanation for why high mantle derived helium is concentrated in this area is the intersection of the ancient Jemez Lineament and the more recent Rio Grande rift. This wildcat has now discovered helium and white hydrogen in the Abo formation. If economically productive the well will be the first helium discovery in the Rio Grande Rift. This could open the rift and its sub basins into a large, new oil, gas and helium and hydrogen producing province.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138992685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.31582/rmag.mg.60.3.197
Tim Rynott
On August 16th, 1960, sitting in an open-air gondola at 103,000’ carefully suspended by a 200’ tall helium balloon, U.S. Air Force Captain Joe Kittinger peers upon cobalt blue skies and the blackest of black (Figure 1). The avant-garde astronaut gets word from the ground crew, “Jump!”, triggering a free fall from 103,000’ and setting the record for the highest skydive ever by any living being (Kittinger, 1961; Kindy, 2023). Captain Joe blazed the trail for the likes of Sheppard, Grissom, and Glenn, testing the limits of the human body. A mere nine years later helium – a relative newcomer to the Periodic table - again flexed its muscle by aiding the propulsion system for Apollo 11’s moon expedition. Jettisoning to 2022, a whopping 180 space launches occurred worldwide, and this number is expected to double in less than seven years. Space tourism leads the pack with an average orbital joyride costing ∼$100K of helium to achieve lift-off (NASA/SpaceEx). During his lonely and ubiquitous ascent into the heavens in 1960, could Captain Kittinger have envisioned the oncoming explosion of helium uses? Could anyone has imagined?
{"title":"Fly Me to the Moon","authors":"Tim Rynott","doi":"10.31582/rmag.mg.60.3.197","DOIUrl":"https://doi.org/10.31582/rmag.mg.60.3.197","url":null,"abstract":"On August 16th, 1960, sitting in an open-air gondola at 103,000’ carefully suspended by a 200’ tall helium balloon, U.S. Air Force Captain Joe Kittinger peers upon cobalt blue skies and the blackest of black (Figure 1). The avant-garde astronaut gets word from the ground crew, “Jump!”, triggering a free fall from 103,000’ and setting the record for the highest skydive ever by any living being (Kittinger, 1961; Kindy, 2023). Captain Joe blazed the trail for the likes of Sheppard, Grissom, and Glenn, testing the limits of the human body. A mere nine years later helium – a relative newcomer to the Periodic table - again flexed its muscle by aiding the propulsion system for Apollo 11’s moon expedition. Jettisoning to 2022, a whopping 180 space launches occurred worldwide, and this number is expected to double in less than seven years. Space tourism leads the pack with an average orbital joyride costing ∼$100K of helium to achieve lift-off (NASA/SpaceEx). During his lonely and ubiquitous ascent into the heavens in 1960, could Captain Kittinger have envisioned the oncoming explosion of helium uses? Could anyone has imagined?","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139023306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.31582/rmag.mg.60.3.141
Ronald F. Broadhead
Helium (He) is the second most abundant element in the universe after hydrogen but is relatively rare on earth. He occurs as two stable isotopes, 3He and 4He. 4He is the dominant isotope in crustal gases and is a radiogenic decay product of uranium and thorium mainly in granitic basement rocks. 3He is dominantly primordial and primarily originates from the earth’s mantle. 3He may also be formed by radiogenic decay of 6Li (Lithium) which may be found in argillaceous sediments deposited in evaporitic settings. Although He occurs in most natural gases, it almost always occurs in extremely low, subeconomic concentrations, less than 0.1%. It is rare in concentrations more than 1%. A very few small reservoirs have gases with more than 7% He. Other gases that constitute the dominant components of helium-bearing natural gases are nitrogen (N2), carbon dioxide (CO2), and methane (CH4). The highest He concentrations occur where the dominant gas is N2 but most He has historically been produced as a byproduct of gases that are hydrocarbons. Hydrocarbons are generated from petroleum source rocks. Their presence in a reservoir is dependent upon the presence of a mature source rock in the basin and a migration path between the source rock and the reservoir. Large accumulations of CO2 in the southwestern U.S. resulted from the degassing of rising Tertiary magmas and subsequent migration of the gases into crustal reservoirs. N2 appears to originate mostly from degassing of the mantle but may also be formed in some strata by the thermal maturation of kerogens or by diagenetic alteration of clays or organic compounds in red bed sequences. The presence of economic concentrations of He in reservoir gases is dependent not only on an adequate source of 4He generated from granitic basement rocks but also on accommodating flux rates of N2, CO2, and CH4. These gases differ in their origins, places of generation and rates of generation, migration and emplacement. While basement-derived 4He and N2 enter reservoirs at slow rates over long periods of geologic time, hydrocarbons and CO2 enter the reservoir over much shorter time periods and dilute the 4He and N2. Basement-derived gases may be characterized by differing N2:He ratios which may indicate greater rates of He production within the crust in some areas. Exploratory drilling for He on Chupadera Mesa in the late 1990’s and early 2000’s encountered He-rich gases in Lower Permian strata. Isotopic analyses suggest that 93% of Chupadera Mesa He originated from radiogenic decay in crustal rocks while 7% is derived from the mantle or with a possible contribution by evaporitic Permian shales. Marked differences in the CO2 concentrations in different strata indicate that some strata acted as carrier beds for magmatically-derived CO2 while strata with N2-rich and CO2-poor gases were isolated from CO2 sources.
氦（He）是宇宙中含量仅次于氢的元素，但在地球上却相对稀少。氦有两种稳定同位素，即 3He 和 4He。4He 是地壳气体中的主要同位素，是铀和钍的放射性衰变产物，主要存在于花岗岩基底岩石中。3He 是主要的原始同位素，主要来源于地幔。3He 也可能是由 6Li（锂）的放射性衰变形成的，可能存在于蒸发环境中沉积的箭状沉积物中。虽然 He 存在于大多数天然气体中，但其浓度几乎总是极低，低于 0.1%。浓度超过 1%的情况则很少见。极少数小型储层中的气体 He 含量超过 7%。构成含氦天然气主要成分的其他气体是氮（N2）、二氧化碳（CO2）和甲烷（CH4）。氦气浓度最高的地方主要是氮气，但历史上大多数氦气都是作为碳氢化合物气体的副产品产生的。碳氢化合物产生于石油源岩。它们在储层中的存在取决于盆地中是否存在成熟的源岩，以及源岩和储层之间的迁移路径。美国西南部的大量二氧化碳积聚是由于上升的第三纪岩浆脱气以及随后气体迁移到地壳储层所致。N2 似乎主要来源于地幔的脱气，但也可能是在某些地层中通过角砾岩的热成熟或红床序列中粘土或有机化合物的成岩蚀变形成的。储层气体中是否存在经济浓度的 He，不仅取决于花岗岩基底岩石产生的 4He 是否充足，还取决于 N2、CO2 和 CH4 的容纳通量。这些气体的来源、生成地点以及生成、迁移和置换速度各不相同。来自基底的 4He 和 N2 在漫长的地质年代中以缓慢的速度进入储层，而碳氢化合物和 CO2 则在更短的时间内进入储层并稀释 4He 和 N2。地层衍生气体的特征可能是不同的 N2:He 比率，这可能表明某些地区地壳内的 He 产生率更高。20 世纪 90 年代末和 21 世纪初在 Chupadera Mesa 进行的 He 勘探钻井在下二叠统地层中发现了富含 He 的气体。同位素分析表明，Chupadera Mesa 93% 的 He 来自地壳岩石中的放射性衰变，7% 来自地幔或二叠纪蒸发页岩。不同地层中二氧化碳浓度的明显差异表明，一些地层是岩浆衍生二氧化碳的载床，而富含 N2 和贫 CO2 气体的地层则与二氧化碳源隔绝。
{"title":"Helium - Relationships to other reservoir gases and some implications for exploration: The New Mexico Example","authors":"Ronald F. Broadhead","doi":"10.31582/rmag.mg.60.3.141","DOIUrl":"https://doi.org/10.31582/rmag.mg.60.3.141","url":null,"abstract":"Helium (He) is the second most abundant element in the universe after hydrogen but is relatively rare on earth. He occurs as two stable isotopes, 3He and 4He. 4He is the dominant isotope in crustal gases and is a radiogenic decay product of uranium and thorium mainly in granitic basement rocks. 3He is dominantly primordial and primarily originates from the earth’s mantle. 3He may also be formed by radiogenic decay of 6Li (Lithium) which may be found in argillaceous sediments deposited in evaporitic settings. Although He occurs in most natural gases, it almost always occurs in extremely low, subeconomic concentrations, less than 0.1%. It is rare in concentrations more than 1%. A very few small reservoirs have gases with more than 7% He. Other gases that constitute the dominant components of helium-bearing natural gases are nitrogen (N2), carbon dioxide (CO2), and methane (CH4). The highest He concentrations occur where the dominant gas is N2 but most He has historically been produced as a byproduct of gases that are hydrocarbons. Hydrocarbons are generated from petroleum source rocks. Their presence in a reservoir is dependent upon the presence of a mature source rock in the basin and a migration path between the source rock and the reservoir. Large accumulations of CO2 in the southwestern U.S. resulted from the degassing of rising Tertiary magmas and subsequent migration of the gases into crustal reservoirs. N2 appears to originate mostly from degassing of the mantle but may also be formed in some strata by the thermal maturation of kerogens or by diagenetic alteration of clays or organic compounds in red bed sequences. The presence of economic concentrations of He in reservoir gases is dependent not only on an adequate source of 4He generated from granitic basement rocks but also on accommodating flux rates of N2, CO2, and CH4. These gases differ in their origins, places of generation and rates of generation, migration and emplacement. While basement-derived 4He and N2 enter reservoirs at slow rates over long periods of geologic time, hydrocarbons and CO2 enter the reservoir over much shorter time periods and dilute the 4He and N2. Basement-derived gases may be characterized by differing N2:He ratios which may indicate greater rates of He production within the crust in some areas. Exploratory drilling for He on Chupadera Mesa in the late 1990’s and early 2000’s encountered He-rich gases in Lower Permian strata. Isotopic analyses suggest that 93% of Chupadera Mesa He originated from radiogenic decay in crustal rocks while 7% is derived from the mantle or with a possible contribution by evaporitic Permian shales. Marked differences in the CO2 concentrations in different strata indicate that some strata acted as carrier beds for magmatically-derived CO2 while strata with N2-rich and CO2-poor gases were isolated from CO2 sources.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139022767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.31582/rmag.mg.60.3.159
Duncan MacKenzie
The following is a survey of a re-emerging helium exploration and production area located at the northwest rim of the Williston Basin located in southwest Saskatchewan, southeastern Alberta, and north central Montana. The Williston Basin is one of the two major sub-basins of the Western Canadian Sedimentary Basin; the other being the Alberta Basin foreland basin, east of the Cordillera. From a slow 2016 start, 21st century helium production from the area already exceeds the total from area’s 1960s and 70s production heyday. As mid-continent legacy helium storage and production decline, the importance of this area’s net-zero helium production can only grow.
{"title":"Recent Developments in Helium Exploitation in southern Saskatchewan and adjacent areas of Montana and Alberta","authors":"Duncan MacKenzie","doi":"10.31582/rmag.mg.60.3.159","DOIUrl":"https://doi.org/10.31582/rmag.mg.60.3.159","url":null,"abstract":"The following is a survey of a re-emerging helium exploration and production area located at the northwest rim of the Williston Basin located in southwest Saskatchewan, southeastern Alberta, and north central Montana. The Williston Basin is one of the two major sub-basins of the Western Canadian Sedimentary Basin; the other being the Alberta Basin foreland basin, east of the Cordillera. From a slow 2016 start, 21st century helium production from the area already exceeds the total from area’s 1960s and 70s production heyday. As mid-continent legacy helium storage and production decline, the importance of this area’s net-zero helium production can only grow.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139020600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-01DOI: 10.31582/rmag.mg.60.3.181
Paul Lafleur
Almost all the helium discovered worldwide has been found by chance in the drilling for hydrocarbons. Targets were usually anticlinal structures located by seismic surveys. The association of helium and natural gas in reservoirs is purely coincidental because the source rocks for each are different—natural gas is mainly produced from diagenesis of carbon rich shale whereas Helium- 4 is derived mainly from the decay of uranium/thorium in the crust. A new geochemical exploration system for helium in the Phanerozoic is considered highly desirable by industry. The current exploration system in the Phanerozoic uses a modified petroleum system concept that has been used successfully for decades to high-grade plays and de-risk oil and gas prospects. Like a petroleum system, the helium system is identified by its source rock, reservoir, trap, seal, and migration pathways. However, this approach is expensive taking years to complete and can be a limiting factor for countries/provinces/states to develop their resources. As a precursor to ground helium/hydrogen surveys for exploration in the Phanerozoic, hyperspectral (satellite) surveys assess huge areas for their helium potential as well as any associated hydrocarbons. These areas may be even devoid of any previous exploration for hydrocarbons. This is followed with geochemical soil gas surveys of the more prospective trends to locate drilling locations. Both methods ascertain whether helium anomalies, which represent helium reservoirs at depth, are associated with hydrocarbons or nitrogen. Helium reservoirs associated with nitrogen are higher in helium content but are deeper, close to the basement. Hyperspectral and geochemical soil gas surveys are also applicable for projects that begin with helium analysis of old wells followed by seismic and drilling. Typically, exploration companies lease vast areas surrounding the legacy well, but their initial focus is on seismic in the area around the legacy well to determine the size and configuration of the helium reservoir and trap penetrated by the well and this is followed by drilling. It is not known at this point whether this reservoir is the best prospect because the helium discovered is usually associated with hydrocarbon (HC), not with nitrogen with much higher helium concentration in the lower Phanerozoic. Rarely do legacy wells penetrate deep enough to this level. Any cost-effective exploration program for helium is best accomplished by hyperspectral and follow-up geochemical soil gas surveys.
{"title":"Exploration for Helium in the Phanerozoic","authors":"Paul Lafleur","doi":"10.31582/rmag.mg.60.3.181","DOIUrl":"https://doi.org/10.31582/rmag.mg.60.3.181","url":null,"abstract":"Almost all the helium discovered worldwide has been found by chance in the drilling for hydrocarbons. Targets were usually anticlinal structures located by seismic surveys. The association of helium and natural gas in reservoirs is purely coincidental because the source rocks for each are different—natural gas is mainly produced from diagenesis of carbon rich shale whereas Helium- 4 is derived mainly from the decay of uranium/thorium in the crust. A new geochemical exploration system for helium in the Phanerozoic is considered highly desirable by industry. The current exploration system in the Phanerozoic uses a modified petroleum system concept that has been used successfully for decades to high-grade plays and de-risk oil and gas prospects. Like a petroleum system, the helium system is identified by its source rock, reservoir, trap, seal, and migration pathways. However, this approach is expensive taking years to complete and can be a limiting factor for countries/provinces/states to develop their resources. As a precursor to ground helium/hydrogen surveys for exploration in the Phanerozoic, hyperspectral (satellite) surveys assess huge areas for their helium potential as well as any associated hydrocarbons. These areas may be even devoid of any previous exploration for hydrocarbons. This is followed with geochemical soil gas surveys of the more prospective trends to locate drilling locations. Both methods ascertain whether helium anomalies, which represent helium reservoirs at depth, are associated with hydrocarbons or nitrogen. Helium reservoirs associated with nitrogen are higher in helium content but are deeper, close to the basement. Hyperspectral and geochemical soil gas surveys are also applicable for projects that begin with helium analysis of old wells followed by seismic and drilling. Typically, exploration companies lease vast areas surrounding the legacy well, but their initial focus is on seismic in the area around the legacy well to determine the size and configuration of the helium reservoir and trap penetrated by the well and this is followed by drilling. It is not known at this point whether this reservoir is the best prospect because the helium discovered is usually associated with hydrocarbon (HC), not with nitrogen with much higher helium concentration in the lower Phanerozoic. Rarely do legacy wells penetrate deep enough to this level. Any cost-effective exploration program for helium is best accomplished by hyperspectral and follow-up geochemical soil gas surveys.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139024903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.31582/rmag.mg.60.2.51
Jane E. Jackson, D. Anderson, M. Silverman
In 2022, the Rocky Mountain Association of Geologists (RMAG) celebrated its centennial anniversary. Founded on January 26, 1922, RMAG (called Rocky Mountain Association of Petroleum Geologists until 1947) grew out of a desire and need for petroleum geologists in Denver to come together in a collegial environment. Petroleum geology had become an important component of exploration and development, with significant discoveries in the greater Denver Basin (Florence Field) as well as east-central Wyoming (Salt Creek Field) and northwest Colorado (Rangely Field). Through the first 25 years (1922–1947), membership hovered around 50, reflecting an initial boom of World War I through the 1920s, and then surviving the Great Depression and World War II. Post-World War II through the early 1980s, the world saw a huge increase in demand for oil (less-so for natural gas), spurring the “golden years” of Rocky Mountain exploration and development of many now-famous discoveries. Denver grew as a petroleum business center with large (major) to small (independent) companies, leading to steady RMAG membership growth, which peaked at 4,524 in 1984. During this period, RMAG established a legacy of publishing (The Mountain Geologist and the Geologic Atlas of the Rocky Mountain Region, aka “the Big Red Book”), sponsored multi-day field trips and symposia, hosted weekly luncheons with 200–300 attendees at the peak, and maintained a dedicated office staff located in downtown Denver. The legacy “golden” years ended with the “crash” in oil prices in 1985–86, and membership declined about 7% per year until the mid-1990s, levelling out at 1,900 members. Within the ashes of the 1984–1995 period, however, RMAG began its On the Rocks field trip series (1986) and published several sold-out guidebooks. It inaugurated the 3D Seismic Symposium (1995) co-hosted with the Denver Geophysical Society (DGS) and hosted several successful AAPG and Rocky Mountain Section AAPG annual meetings. In the 1990s, natural gas hosted in “unconventional” reservoirs began an exploration/development revolution, spurred on by federal price supports and construction of a major gas pipeline to the West Coast in 1992. By 2000, huge natural gas resources locked in Rocky Mountain “tight gas” reservoirs became economically viable with improved hydraulic fracturing technology and increasing gas prices. RMAG membership began growing along with the increased natural gas-drilling activity, and RMAG offered multiple well-attended symposia and publications highlighting unconventional gas plays. A new boom began in 2008 with the advent of horizontal drilling for oil in the Bakken Shale of the Williston Basin and Niobrara Formation of the Denver Basin, and a massive increase in oil price. Consequently, RMAG membership reached a secondary peak of 2,978 in 2012. However, as oil prices began declining steadily in 2014, membership also decreased. By 2016, oil price decline led to the familiar cycle of company closings and
{"title":"Celebrating 100 Years of the Rocky Mountain Association of Geologist","authors":"Jane E. Jackson, D. Anderson, M. Silverman","doi":"10.31582/rmag.mg.60.2.51","DOIUrl":"https://doi.org/10.31582/rmag.mg.60.2.51","url":null,"abstract":"In 2022, the Rocky Mountain Association of Geologists (RMAG) celebrated its centennial anniversary. Founded on January 26, 1922, RMAG (called Rocky Mountain Association of Petroleum Geologists until 1947) grew out of a desire and need for petroleum geologists in Denver to come together in a collegial environment. Petroleum geology had become an important component of exploration and development, with significant discoveries in the greater Denver Basin (Florence Field) as well as east-central Wyoming (Salt Creek Field) and northwest Colorado (Rangely Field). Through the first 25 years (1922–1947), membership hovered around 50, reflecting an initial boom of World War I through the 1920s, and then surviving the Great Depression and World War II. Post-World War II through the early 1980s, the world saw a huge increase in demand for oil (less-so for natural gas), spurring the “golden years” of Rocky Mountain exploration and development of many now-famous discoveries. Denver grew as a petroleum business center with large (major) to small (independent) companies, leading to steady RMAG membership growth, which peaked at 4,524 in 1984. During this period, RMAG established a legacy of publishing (The Mountain Geologist and the Geologic Atlas of the Rocky Mountain Region, aka “the Big Red Book”), sponsored multi-day field trips and symposia, hosted weekly luncheons with 200–300 attendees at the peak, and maintained a dedicated office staff located in downtown Denver. The legacy “golden” years ended with the “crash” in oil prices in 1985–86, and membership declined about 7% per year until the mid-1990s, levelling out at 1,900 members. Within the ashes of the 1984–1995 period, however, RMAG began its On the Rocks field trip series (1986) and published several sold-out guidebooks. It inaugurated the 3D Seismic Symposium (1995) co-hosted with the Denver Geophysical Society (DGS) and hosted several successful AAPG and Rocky Mountain Section AAPG annual meetings. In the 1990s, natural gas hosted in “unconventional” reservoirs began an exploration/development revolution, spurred on by federal price supports and construction of a major gas pipeline to the West Coast in 1992. By 2000, huge natural gas resources locked in Rocky Mountain “tight gas” reservoirs became economically viable with improved hydraulic fracturing technology and increasing gas prices. RMAG membership began growing along with the increased natural gas-drilling activity, and RMAG offered multiple well-attended symposia and publications highlighting unconventional gas plays. A new boom began in 2008 with the advent of horizontal drilling for oil in the Bakken Shale of the Williston Basin and Niobrara Formation of the Denver Basin, and a massive increase in oil price. Consequently, RMAG membership reached a secondary peak of 2,978 in 2012. However, as oil prices began declining steadily in 2014, membership also decreased. By 2016, oil price decline led to the familiar cycle of company closings and","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129566431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alkaline to subalkaline mafic dikes in the 28 to 18 Ma Dulce swarm were emplaced in a zone of incipient extension from southern Colorado into northern New Mexico on the northeastern boundary of the San Juan Basin. The 87Sr/86Sr ratios for the dikes are 0.70503 to 0.70584, akin to most post-28 Ma mafic rocks across the northern San Juan Basin. These data are consistent with melting of metasomatized subcontinental lithospheric mantle with little to no crustal contribution as revealed by the geochemical and Sr-Nd isotopic signatures of most 28–0.6 Ma mafic rocks in the region. Time-corrected εNd(t) values of −4.1 to −7.4 for rocks in the Dulce swarm, however, indicate that magma production involved the crust. A previous hypothesis for Dulce magmas was contamination of lithospheric mantle melts with up to 45% mafic lower crust ± 0.5% upper crust. In this investigation, six new whole-rock Sr and Nd isotopic analyses were combined with published data to further investigate the contamination of lithospheric mantle melts with different crustal reservoirs. The Nd isotope signatures of the Dulce swarm offer evidence for the long-term involvement (∼10 Ma) of lower crust in the production of rift-related mantle magmas. Isotopic mixing curves support previous hypotheses for the contamination of lithospheric mantle melts with 10 to 40 percent lower mafic crust. This provides further insight into regional variations in mantle magmas produced after 28 Ma in the Four Corners region that likely triggered crustal melting related to caldera complexes in the western San Juan Mountains.
{"title":"Assessing crustal contamination in the 28 to 18 Ma Dulce dike swarm with Nd-Sr isotopic data, southwestern Colorado","authors":"W. M. McCormick, D. Gonzales","doi":"10.31582/rmag.mg.60.1.5","DOIUrl":"https://doi.org/10.31582/rmag.mg.60.1.5","url":null,"abstract":"Alkaline to subalkaline mafic dikes in the 28 to 18 Ma Dulce swarm were emplaced in a zone of incipient extension from southern Colorado into northern New Mexico on the northeastern boundary of the San Juan Basin. The 87Sr/86Sr ratios for the dikes are 0.70503 to 0.70584, akin to most post-28 Ma mafic rocks across the northern San Juan Basin. These data are consistent with melting of metasomatized subcontinental lithospheric mantle with little to no crustal contribution as revealed by the geochemical and Sr-Nd isotopic signatures of most 28–0.6 Ma mafic rocks in the region. Time-corrected εNd(t) values of −4.1 to −7.4 for rocks in the Dulce swarm, however, indicate that magma production involved the crust. A previous hypothesis for Dulce magmas was contamination of lithospheric mantle melts with up to 45% mafic lower crust ± 0.5% upper crust. In this investigation, six new whole-rock Sr and Nd isotopic analyses were combined with published data to further investigate the contamination of lithospheric mantle melts with different crustal reservoirs. The Nd isotope signatures of the Dulce swarm offer evidence for the long-term involvement (∼10 Ma) of lower crust in the production of rift-related mantle magmas. Isotopic mixing curves support previous hypotheses for the contamination of lithospheric mantle melts with 10 to 40 percent lower mafic crust. This provides further insight into regional variations in mantle magmas produced after 28 Ma in the Four Corners region that likely triggered crustal melting related to caldera complexes in the western San Juan Mountains.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132042408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-01DOI: 10.31582/rmag.mg.59.4.273
J. Malone, J. Craddock, D. Malone
Detrital zircon ages for tuffaceous sandstones and conglomerates of the White River Group provide insights on Paleogene basin evolution, magmatic activity, and paleodrainage throughout the Laramide broken foreland basin system of the northern Rocky Mountains in the western United States. Nonmarine deposits of the upper Eocene-Oligocene White River Group are preserved irregularly across northern Wyoming and western South Dakota. Residual Laramide uplifts and active magmatic centers supplied clastic and volcaniclastic sediment to broad, low-relief valleys beginning around 40 Ma. Subhorizontal strata of the White River Group are exposed in the elevated Bighorn Mountains (∼2300 to 2800 m), where sections ∼10-50 m thick rest unconformably on Precambrian-Paleozoic rocks along a surface of moderate to low relief (up to 150 m). U-Pb ages were obtained for detrital and igneous (ash-fall) zircons from seven samples (3 tuffaceous sandstones, 2 conglomerates, 2 sandstones) spanning three localities in the Bighorn Mountains (Darton’s Bluff, Hazelton Road, Freeze Out Point). Each locality contains conglomeratic layers, with clasts of local crystalline basement, and interbedded tuffaceous sandstones. Detrital zircon age spectra for four samples reveal peak ages around 2.9 Ga, matching the age of Archean crystalline basement within Bighorn Mountains, and maximum depositional ages (MDAs) of 27 Ma (sample 20BH15; Oligocene) and 35 Ma (sample FO-2; late Eocene). During the Paleogene, the Bighorn Mountains region received sediment from local crystalline basement and long-distance river transport from igneous and sedimentary sources to the west. The Bighorn Mountains were exhumed and stripped of Phanerozoic cover strata by early Eocene time, suggesting that post-Laramide input from Paleozoic-Mesozoic strata was likely from relict highlands of the Cordilleran (Sevier) fold-thrust belt rather than local Laramide block uplifts. In addition, Cenozoic magmatic provinces in the San Juan Mountains and Great Basin are inferred to have contributed volcaniclastic sediment through both eruptive ash clouds and north- to northeast-flowing fluvial systems that reached northeastern Wyoming. The White River Group preserved in the Bighorn Mountains represents localized late Eocene-Oligocene sediment accumulation atop a Laramide basement high coeval with regional deposition across the adjacent Great Plains. Both regions were supplied sediment from alluvial fans and fluvial drainage networks that tapped Laramide basement uplifts, Cordilleran thrust-belt, and foreland sources, along with Cenozoic igneous centers of the western U.S. interior.
{"title":"Sediment provenance and stratigraphic correlations of the Paleogene White River Group in the Bighorn Mountains, Wyoming","authors":"J. Malone, J. Craddock, D. Malone","doi":"10.31582/rmag.mg.59.4.273","DOIUrl":"https://doi.org/10.31582/rmag.mg.59.4.273","url":null,"abstract":"Detrital zircon ages for tuffaceous sandstones and conglomerates of the White River Group provide insights on Paleogene basin evolution, magmatic activity, and paleodrainage throughout the Laramide broken foreland basin system of the northern Rocky Mountains in the western United States. Nonmarine deposits of the upper Eocene-Oligocene White River Group are preserved irregularly across northern Wyoming and western South Dakota. Residual Laramide uplifts and active magmatic centers supplied clastic and volcaniclastic sediment to broad, low-relief valleys beginning around 40 Ma. Subhorizontal strata of the White River Group are exposed in the elevated Bighorn Mountains (∼2300 to 2800 m), where sections ∼10-50 m thick rest unconformably on Precambrian-Paleozoic rocks along a surface of moderate to low relief (up to 150 m). U-Pb ages were obtained for detrital and igneous (ash-fall) zircons from seven samples (3 tuffaceous sandstones, 2 conglomerates, 2 sandstones) spanning three localities in the Bighorn Mountains (Darton’s Bluff, Hazelton Road, Freeze Out Point). Each locality contains conglomeratic layers, with clasts of local crystalline basement, and interbedded tuffaceous sandstones. Detrital zircon age spectra for four samples reveal peak ages around 2.9 Ga, matching the age of Archean crystalline basement within Bighorn Mountains, and maximum depositional ages (MDAs) of 27 Ma (sample 20BH15; Oligocene) and 35 Ma (sample FO-2; late Eocene). During the Paleogene, the Bighorn Mountains region received sediment from local crystalline basement and long-distance river transport from igneous and sedimentary sources to the west. The Bighorn Mountains were exhumed and stripped of Phanerozoic cover strata by early Eocene time, suggesting that post-Laramide input from Paleozoic-Mesozoic strata was likely from relict highlands of the Cordilleran (Sevier) fold-thrust belt rather than local Laramide block uplifts. In addition, Cenozoic magmatic provinces in the San Juan Mountains and Great Basin are inferred to have contributed volcaniclastic sediment through both eruptive ash clouds and north- to northeast-flowing fluvial systems that reached northeastern Wyoming. The White River Group preserved in the Bighorn Mountains represents localized late Eocene-Oligocene sediment accumulation atop a Laramide basement high coeval with regional deposition across the adjacent Great Plains. Both regions were supplied sediment from alluvial fans and fluvial drainage networks that tapped Laramide basement uplifts, Cordilleran thrust-belt, and foreland sources, along with Cenozoic igneous centers of the western U.S. interior.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122872900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-01DOI: 10.31582/rmag.mg.59.4.295
A. M. Thorson, S. Atchley, Elisabeth G. Rau, David W. Yeates
The Duvernay Formation accumulated as an organic-rich basinal mudrock concurrent with shallow marine platform carbonates of the Leduc and Grosmont formations. Historically classified as a major source rock to conventional hydrocarbon production, the Duvernay evolved into an unconventional shale reservoir across Alberta, Canada much like other source rock intervals worldwide. Distributions of the Duvernay Formation are partitioned into the West and East Shale basins by a narrow, linear Leduc Formation reef complex known as the Rimbey-Meadowbrook trend. Since 2011, development has focused on the West Shale Basin, but thermal maturity trends suggest the potential for expanded shale reservoir development within the southern portion of the East Shale Basin. This study characterizes sedimentologic and stratigraphic controls on Duvernay reservoir potential to identify development “sweet spots” within the East Shale Basin. Duvernay geologic attributes mapped within this study include: oil thermal maturity, thick restricted basin facies association occurrence (at least 5-10m thick), high average TOC values (greater than 2.0 wt.%), and high net carbonate thickness (greater than 40m). The geologic attributes are predictive of production potential within horizontal wells, and the distribution of their co-occurrence suggests the potential for expanded development within the southern portion of the East Shale Basin.
{"title":"Controls on East Shale Basin reservoir distribution within the Upper Devonian Duvernay Formation, Western Canada Sedimentary Basin","authors":"A. M. Thorson, S. Atchley, Elisabeth G. Rau, David W. Yeates","doi":"10.31582/rmag.mg.59.4.295","DOIUrl":"https://doi.org/10.31582/rmag.mg.59.4.295","url":null,"abstract":"The Duvernay Formation accumulated as an organic-rich basinal mudrock concurrent with shallow marine platform carbonates of the Leduc and Grosmont formations. Historically classified as a major source rock to conventional hydrocarbon production, the Duvernay evolved into an unconventional shale reservoir across Alberta, Canada much like other source rock intervals worldwide. Distributions of the Duvernay Formation are partitioned into the West and East Shale basins by a narrow, linear Leduc Formation reef complex known as the Rimbey-Meadowbrook trend. Since 2011, development has focused on the West Shale Basin, but thermal maturity trends suggest the potential for expanded shale reservoir development within the southern portion of the East Shale Basin. This study characterizes sedimentologic and stratigraphic controls on Duvernay reservoir potential to identify development “sweet spots” within the East Shale Basin. Duvernay geologic attributes mapped within this study include: oil thermal maturity, thick restricted basin facies association occurrence (at least 5-10m thick), high average TOC values (greater than 2.0 wt.%), and high net carbonate thickness (greater than 40m). The geologic attributes are predictive of production potential within horizontal wells, and the distribution of their co-occurrence suggests the potential for expanded development within the southern portion of the East Shale Basin.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130617880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-01DOI: 10.31582/rmag.mg.59.4.315
Timothy O. Nesheim, C. Onwumelu
The Mississippian Madison Group has been the most productive conventional oil play interval in the Williston Basin with more than 32,000 productive wells and 4.6 billion BOE of cumulative production to date. After 70+ years of exploration and development in the unit, the Madison could be considered a relatively “mature” hydrocarbon play interval. Initial geochemical fingerprinting studies beginning in the 1970’s linked Madison reservoir oils to the underlying Bakken shale source beds. However, numerous ensuing geochemical fingerprinting studies with improved technology and techniques have concluded that most Madison reservoir oils are distinct from Bakken oils and therefore were internally sourced by undefined Madison source rock(s). Previously undocumented carbonate source rock intervals are observed in core and wireline logs within the upper Lodgepole/lower Tilston and lower Bluell stratigraphic section of the Madison Group. Both source rock intervals contain present day TOC values of 1% to ≥5%, plot along Type I/II (oil prone) kerogen signatures using hydrogen versus oxygen index values, reach 40+ feet (12+ m) gross thickness, extend laterally in the subsurface for at least tens of miles (1-2 million acres), and appear to be within the peak oil generation window (436-456° Tmax). Understanding the stratigraphic positions, lateral extents, and hydrocarbon generation significance of petroleum source beds may be the key to unlocking one or more unconventional Madison resource plays within the Williston Basin.
{"title":"Preliminary identification and evaluation of petroleum source beds within the Mississippian Madison Group: A step toward redefining the Madison petroleum system of the Williston Basin","authors":"Timothy O. Nesheim, C. Onwumelu","doi":"10.31582/rmag.mg.59.4.315","DOIUrl":"https://doi.org/10.31582/rmag.mg.59.4.315","url":null,"abstract":"The Mississippian Madison Group has been the most productive conventional oil play interval in the Williston Basin with more than 32,000 productive wells and 4.6 billion BOE of cumulative production to date. After 70+ years of exploration and development in the unit, the Madison could be considered a relatively “mature” hydrocarbon play interval. Initial geochemical fingerprinting studies beginning in the 1970’s linked Madison reservoir oils to the underlying Bakken shale source beds. However, numerous ensuing geochemical fingerprinting studies with improved technology and techniques have concluded that most Madison reservoir oils are distinct from Bakken oils and therefore were internally sourced by undefined Madison source rock(s). Previously undocumented carbonate source rock intervals are observed in core and wireline logs within the upper Lodgepole/lower Tilston and lower Bluell stratigraphic section of the Madison Group. Both source rock intervals contain present day TOC values of 1% to ≥5%, plot along Type I/II (oil prone) kerogen signatures using hydrogen versus oxygen index values, reach 40+ feet (12+ m) gross thickness, extend laterally in the subsurface for at least tens of miles (1-2 million acres), and appear to be within the peak oil generation window (436-456° Tmax). Understanding the stratigraphic positions, lateral extents, and hydrocarbon generation significance of petroleum source beds may be the key to unlocking one or more unconventional Madison resource plays within the Williston Basin.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115834806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：