scholarly journals Gas migration for terrestrial gas hydrates in the Juhugeng mining area of Muli basin, Qilian Mountains, Northwest China

2020 ◽  
Vol 38 (4) ◽  
pp. 989-1013 ◽  
Author(s):  
Anmin Wang ◽  
Jing Li ◽  
Yingchun Wei ◽  
Chengwei Yang ◽  
Jing Nie ◽  
...  

The Juhugeng mining area in the Qilian Mountains is the only district of China where terrestrial gas hydrate has been found. This paper aimed at studying the gas migration for gas hydrates based on fluid inclusion and apatite fission track experiments with samples being collected in both the hanging wall (Triassic strata, non-hydrocarbon source rocks) and footwall (Jurassic strata, hydrocarbon source rocks) of drilling cores. Fluid inclusions are found in both the hanging wall and footwall, and are characterized by two generations: the first generation includes gaseous and liquid hydrocarbon fluid inclusions with the homogenization temperature of concomitant saline water inclusions being 83–115°C, and the second generation includes gaseous fluid inclusions with the concomitant homogenization temperature of saline water inclusions being 115–149 °C, suggesting two periods of gas migration. Combining with the reconstruction of the burial and thermal histories, the gas migration history can be elaborated as follows: (1) In the Late Paleogene period (>30 Ma), the gas in the footwall migrated to the hanging wall because of the thrusting of Triassic strata, with the temperature being more than 110 ± 10°C (derived from apatite fission track results), corresponding well with the homogenization temperature of the saline water inclusions of the first generation being 115–149 °C; (2) In the Late Neogene to Quaternary (<8 Ma), the study area were impacted by the intensive faults, leading to the second gas migration with a good match between temperature lower than 110 ± 10°C (derived from apatite fission track results) and the homogenization temperature of saline water inclusions in the second generation (83–115 °C), and the geological age of the second gas migration can be restricted from 8 to 1.8 Ma. The permafrost was formed in Quaternary, so the controversial gas hydrate formation pattern can be determined that the gas should be accumulated before the permafrost was formed.

2013 ◽  
Vol 50 (6) ◽  
pp. 607-635 ◽  
Author(s):  
Yawooz A. Kettanah

Fluid inclusions hosted in rock salt from the Triassic Argo Formation in the Canadian Atlantic continental margin were studied to investigate the nature and origin of petroleum fluids in them. Inclusions were studied in two wells: Glooscap-C63 and Weymouth-A45. The pillow-shaped salt body intersected by the Glooscap-C63 well is autochthonous, and the salt is transparent and colorless compared with that in the allochthonous, canopy–diaper-shaped body cut by the Weymouth-A45 well which is translucent and buff-colored. Aqueous (AFI), petroleum (PFI), and heterogeneously trapped, mixed petroleum – aqueous (MFI) fluid inclusions were identified using transmitted and fluorescent microscopy, and representative samples were analyzed microthermometrically. Petroleum-bearing fluid inclusions (PFI and MFI) are more common and contain more concentrated petroleum phases in the allochthonous salts of Weymouth-A45 well. Based on microthermometric studies, the AFI and MFI in Glooscap-C63 salt mostly belong to NaCl–H2O and NaCl–H2O–petroleum systems, respectively; in contrast, those of Weymouth-A45 belong to NaCl–MgCl2–H2O and (or) NaCl–CaCl2–H2O and NaCl–MgCl2–H2O–petroleum and (or) NaCl–CaCl2–H2O–petroleum systems, respectively. Each of the AFI, PFI, and MFI types consists of different phases. The medians of Tf (freezing temperature), Tim (initial melting temperature), Te (Eutectic temperature), Tm (final melting (peritectic) temperature), and Th (homogenization temperature) in the AFI and MFI in the salts of Glooscap-C63 well are (−82, −75 °C), (−39, −38 °C), (−25, −24 °C), (−1.8, −3 °C), and (291, 287 °C), respectively. The corresponding medians for the Weymouth-A45 well are (−71, −78 °C), (−52, −52 °C), (−37, −38 °C), (−2.7, −3 °C), and (122, 20 °C), respectively. The median Th of PFI in Glooscap-C63 and Weymouth-A45 salts are 79 and 23 °C, respectively. The most probable source rocks for the petroleum are the shales of the Late Triassic – Early Jurassic Eurydice Formation which is widely distributed at depth underlying the Argo salt.


2021 ◽  
Author(s):  
Jennifer Spalding ◽  
Jeremy Powell ◽  
David Schneider ◽  
Karen Fallas

&lt;p&gt;Resolving the thermal history of sedimentary basins through geological time is essential when evaluating the maturity of source rocks within petroleum systems. Traditional methods used to estimate maximum burial temperatures in prospective sedimentary basin such as and vitrinite reflectance (%Ro) are unable to constrain the timing and duration of thermal events. In comparison, low-temperature thermochronology methods, such as apatite fission track thermochronology (AFT), can resolve detailed thermal histories within a temperature range corresponding to oil and gas generation. In the Peel Plateau of the Northwest Territories, Canada, Phanerozoic sedimentary strata exhibit oil-stained outcrops, gas seeps, and bitumen occurrences. Presently, the timing of hydrocarbon maturation events are poorly constrained, as a regional unconformity at the base of Cretaceous foreland basin strata indicates that underlying Devonian source rocks may have undergone a burial and unroofing event prior to the Cretaceous. Published organic thermal maturity values from wells within the study area range from 1.59 and 2.46 %Ro for Devonian strata and 0.54 and 1.83 %Ro within Lower Cretaceous strata. Herein, we have resolved the thermal history of the Peel Plateau through multi-kinetic AFT thermochronology. Three samples from Upper Devonian, Lower Cretaceous and Upper Cretaceous strata have pooled AFT ages of 61.0 &amp;#177; 5.1 Ma, 59.5 &amp;#177; 5.2 and 101.6 &amp;#177; 6.7 Ma, respectively, and corresponding U-Pb ages of 497.4 &amp;#177; 17.5 Ma (MSWD: 7.4), 353.5 &amp;#177; 13.5 Ma (MSWD: 3.1) and 261.2 &amp;#177; 8.5 Ma (MSWD: 5.9). All AFT data fail the &amp;#967;&lt;sup&gt;2&lt;/sup&gt; test, suggesting AFT ages do not comprise a single statistically significant population, whereas U-Pb ages reflect the pre-depositional history of the samples and are likely from various provenances. Apatite chemistry is known to control the temperature and rates at which fission tracks undergo thermal annealing. The r&lt;sub&gt;mro&lt;/sub&gt; parameter uses grain specific chemistry to predict apatite&amp;#8217;s kinetic behaviour and is used to identify kinetic populations within samples. Grain chemistry was measured via electron microprobe analysis to derive r&lt;sub&gt;mro&lt;/sub&gt; values and each sample was separated into two kinetic populations that pass the &amp;#967;&lt;sup&gt;2&lt;/sup&gt; test: a less retentive population with ages ranging from 49.3 &amp;#177; 9.3 Ma to 36.4 &amp;#177; 4.7 Ma, and a more retentive population with ages ranging from 157.7 &amp;#177; 19 Ma to 103.3 &amp;#177; 11.8 Ma, with r&lt;sub&gt;mr0&lt;/sub&gt; benchmarks ranging from 0.79 and 0.82. Thermal history models reveal Devonian strata reached maximum burial temperatures (~165&amp;#176;C-185&amp;#176;C) prior to late Paleozoic to Mesozoic unroofing, and reheated to lower temperatures (~75&amp;#176;C-110&amp;#176;C) in the Late Cretaceous to Paleogene. Both Cretaceous samples record maximum burial temperatures (75&amp;#176;C-95&amp;#176;C) also during the Late Cretaceous to Paleogene. These new data indicate that Devonian source rocks matured prior to deposition of Cretaceous strata and that subsequent burial and heating during the Cretaceous to Paleogene was limited to the low-temperature threshold of the oil window. Integrating multi-kinetic AFT data with traditional methods in petroleum geosciences can help unravel complex thermal histories of sedimentary basins. Applying these methods elsewhere can improve the characterisation of petroleum systems.&lt;/p&gt;


1992 ◽  
Vol 29 (5) ◽  
pp. 909-924 ◽  
Author(s):  
A. M. Grist ◽  
P. H. Reynolds ◽  
M. Zentilli ◽  
C. Beaumont

Apatite fission track and 40Ar/39Ar age spectrum data from sandstone drill-core minerals taken from depths of 2–5 km in nine wells from the Scotian Basin are presented and interpreted in terms of the thermal history of the basin and the provenance of its sediments. The focus of the study is a comparison of the data from these thermochronometers with each other and with previously published vitrinite reflectance and aromatization–isomerization (A–I) reactions in biomarker compounds from the same or nearby wells.Apatite fission track ages are generally in agreement with expectations in that they trend to zero at a depth of ~4 km (corrected bottom-hole temperature ~120 °C). Shallower (lower present temperature) samples are partially annealed; the degree of partial annealing correlates closely with the degree of A–I reactions. Both thermal indicators are activated over the temperature range 60–120 °C.Samples from two wells, Mic Mac J-77 and Erie D-26, are anomalous. They are more annealed than present formation temperatures would predict, an anomaly that is also indicated by the A–I data. These samples are interpreted as having experienced higher than present temperatures subsequent to deposition, possibly resulting from the passage of hot fluids related to localized volcanism or the sudden venting of an overpressured reservoir.K-feldspars record minor (< 20%) argon loss as a result of burial heating in the basin only at the greatest depths of the sampled range (> 4.3 km). This result is in agreement with the thermal models of the Scotian Basin and extrapolation of the A–I and fission track data to greater depths. The inferred argon loss implies an activation energy of 40 ± 4 kcal/mol for the smallest diffusion domains.The argon age spectra for samples that have not lost argon during residence in the basin provide evidence on the provenance of the sediments. K-feldspars from the Early Cretaceous Missisauga Formation have spectra that are similar to those obtained from K-feldspars from the Grenville Province of the Canadian Shield, whereas muscovites from the same formation give Cambrian to Carboniferous argon ages (mean 387 Ma), an indication of contributions from other source rocks. Corresponding data from the Jurassic Mohican Formation are similar to those reported for plutons from the southern Nova Scotia mainland (ca. 250–350 Ma argon ages). By implication, the Mohican Formation, which is the earliest postrift deposit, was derived from local sources inferred to be adjacent flank uplifts, whereas the Missisauga Formation was derived in part either directly or indirectly from the Grenvillian-aged interior of eastern Canada.


1996 ◽  
Vol 36 (1) ◽  
pp. 322
Author(s):  
E.M. Alexander ◽  
D. Pegum ◽  
P. Tingate ◽  
C.J. Staples ◽  
B.H. Michaelsen ◽  
...  

The Eringa Trough occupies an area of over 8,000 km2 in SA and the NT and contains an estimated 1,500 m of Permo-Carboniferous and over 1,000 m of Mesozoic sediments. Early Permian depositional history of this frontier region is similar to that of the Cooper Basin in northeastern SA. The Eringa Trough has limited seismic coverage and sparse petroleum and mineral exploration drillholes are located on the trough margins. Interpretation of 255 km of new seismic and reprocessed data has delineated a number of undrilled prospects.Excellent quality reservoirs are present. Early mature to mature, Permian and Jurassic source rocks occur, including good to excellent Type-II kerogens within an equivalent of the Jurassic Birkhead Formation. Apatite fission track analysis of Permian and Jurassic sediment shows palaeo-temperatures were approximately 30-40°C higher than at present and that cooling occurred within the last 60 Ma. This suggests that Permian and Jurassic sediments in the deeper parts of the Eringa Trough have experienced temperatures suitable for petroleum generation.An integrated evaluation of the Eringa Trough in SA and the NT has resulted in a greater understanding of this frontier area which has the potential for significant commercial petroleum discoveries.


2013 ◽  
Vol 50 (5) ◽  
pp. 576-598 ◽  
Author(s):  
J.F. Cubley ◽  
D.R.M. Pattison ◽  
D.A. Archibald ◽  
M. Jolivet

The Grand Forks complex (GFC) is a metamorphic core complex within the composite Shuswap complex in the southern Omineca belt of the Canadian Cordillera. It is juxtaposed against the surrounding low-grade rocks of the pericratonic Quesnel terrane by outward-dipping Eocene normal faults. The GFC attained peak metamorphic conditions of 750–800 °C and 5.5–6.0 kbar (1 kbar = 100 MPa) in the late Paleocene to early Eocene, followed by ∼2.5 kbar of near-isothermal decompression at upper-amphibolite to granulite facies conditions (∼725–750 °C) in the early Eocene. Subsequent low-temperature greenschist-facies exhumation (∼0.7–1.5 kbar) was accommodated by the brittle–ductile Kettle River normal fault (KRF) on the east flank of the complex and the Granby fault (GF) on the west flank. This study presents 16 new 40Ar/39Ar hornblende and biotite dates from the GFC and low-grade rocks in the hanging walls to the KRF and GF. Cooling of the GFC through the closure temperature of hornblende (∼ 530 °C) is constrained to the interval between ∼54 and 51.4 ± 0.5 Ma, whereas cooling through the closure temperature of biotite (∼280 °C) occurred at 51.4 ± 0.2 Ma. In the hanging wall of the KRF, cooling through the closure temperature of hornblende and biotite occurred nearly coevally at 51.7 ± 0.6 Ma and 51.0 ± 1.0 Ma, respectively. Five apatite fission track dates (closure temperature ∼110 °C) from the GFC and adjacent hanging walls are indistinguishable within error, yielding an average age of 34.6 ± 2.0 Ma. The lack of difference in biotite and apatite ages between the GFC and the low-grade hanging wall rocks against which it is juxtaposed suggests no significant movement on the KRF and GF after ca. 51 Ma. Results from this study and a previous study on U–Pb dating of the GFC document rapid cooling of the GFC in excess of 200 °C/Ma in a 4 Ma interval between 55 and 51 Ma (Eocene). This rapid phase of exhumation of the GFC was followed by 15 Ma of slow cooling (∼10 °C/Ma) of the joined GFC and hanging wall between ∼280 °C (biotite closure) and ∼110 °C (apatite closure).


2015 ◽  
Vol 66 (1) ◽  
pp. 37-50 ◽  
Author(s):  
Nevena Andrić ◽  
Bernhard Fügenschuh ◽  
Dragana Životić ◽  
Vladica Cvetković

Abstract The Ibar Basin was formed during Miocene large scale extension in the NE Dinaride segment of the Alpine- Carpathian-Dinaride system. The Miocene extension led to exhumation of deep seated core-complexes (e.g. Studenica and Kopaonik core-complex) as well as to the formation of extensional basins in the hanging wall (Ibar Basin). Sediments of the Ibar Basin were studied by apatite and zircon fission track and vitrinite reflectance in order to define thermal events during basin evolution. Vitrinite reflectance (VR) data (0.63-0.90 %Rr) indicate a bituminous stage for the organic matter that experienced maximal temperatures of around 120-130 °C. Zircon fission track (ZFT) ages indicate provenance ages. The apatite fission track (AFT) single grain ages (45-6.7 Ma) and bimodal track lengths distribution indicate partial annealing of the detrital apatites. Both vitrinite reflectance and apatite fission track data of the studied sediments imply post-depositional thermal overprint in the Ibar Basin. Thermal history models of the detritial apatites reveal a heating episode prior to cooling that began at around 10 Ma. The heating episode started around 17 Ma and lasted 10-8 Ma reaching the maximum temperatures between 100-130 °C. We correlate this event with the domal uplift of the Studenica and Kopaonik cores where heat was transferred from the rising warm footwall to the adjacent colder hanging wall. The cooling episode is related to basin inversion and erosion. The apatite fission track data indicate local thermal perturbations, detected in the SE part of the Ibar basin (Piskanja deposit) with the time frame ~7.1 Ma, which may correspond to the youngest volcanic phase in the region.


2020 ◽  
pp. 014459872097451
Author(s):  
Wenqi Jiang ◽  
Yunlong Zhang ◽  
Li Jiang

A fluid inclusion petrographic and microthermometric study was performed on the sandstones gathered from the Yanchang Formation, Jiyuan area of the Ordos Basin. Four types of fluid inclusions in quartz can be recognized based on the location they entrapped. The petrographic characteristics indicate that fluid inclusions in quartz overgrowth and quartz fissuring-I were trapped earlier than that in quartz fissuring-IIa and fissuring-IIb. The homogenization temperature values of the earlier fluid inclusions aggregate around 80 to 90°C; exclusively, it is slightly higher in Chang 6 member, which approaches 95°C. The later fluid inclusions demonstrate high homogenization temperatures, which range from 100 to 115°C, and the temperatures are slightly higher in Chang 9 member. The calculated salinities show differences between each member, including their regression characteristics with burial depth. Combining with the vitrinite reflection data, the sequence and parameters of fluid inclusions indicate that the thermal history of the Yanchang formation mostly relied on burial. Salinity changes were associated with fluid-rock interaction or fluid interruption. Hydrocarbon contained fluid inclusions imply that hydrocarbon generation and migration occurred in the Early Cretaceous. The occurrence of late fluid inclusions implied that quartz cement is a reservoir porosity-loose factor.


Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 604
Author(s):  
Evgeny V. Vetrov ◽  
Johan De Grave ◽  
Natalia I. Vetrova ◽  
Fedor I. Zhimulev ◽  
Simon Nachtergaele ◽  
...  

The West Siberian Basin (WSB) is one of the largest intracratonic Meso-Cenozoic basins in the world. Its evolution has been studied over the recent decades; however, some fundamental questions regarding the tectonic evolution of the WSB remain unresolved or unconfirmed by analytical data. A complete understanding of the evolution of the WSB during the Mesozoic and Cenozoic eras requires insights into the cooling history of the basement rocks as determined by low-temperature thermochronometry. We presented an apatite fission track (AFT) thermochronology study on the exposed parts of the WSB basement in order to distinguish tectonic activation episodes in an absolute timeframe. AFT dating of thirteen basement samples mainly yielded Cretaceous cooling ages and mean track lengths varied between 12.8 and 14.5 μm. Thermal history modeling based on the AFT data demonstrates several Mesozoic and Cenozoic intracontinental tectonic reactivation episodes affected the WSB basement. We interpreted the episodes of tectonic activity accompanied by the WSB basement exhumation as a far-field effect from tectonic processes acting on the southern and eastern boundaries of Eurasia during the Mesozoic–Cenozoic eras.


2012 ◽  
Vol 616-618 ◽  
pp. 174-184
Author(s):  
Yong He Sun ◽  
Lin Kang ◽  
Feng Xiang Yang ◽  
Xue Song Li

In order to reveal in middle fault depression belt of Hailer-Tamtsag Basin buried hill oil and gas migration and accumulation characteristics, we summarize controlling effect of fault on oil and gas migration and accumulation of buried hill, which by analysing genetic mechanism of buried hills based on fault systems formation and evolution. Research shows that three types of fault system in Hailer-Tamtsag Basin: early stretched fault system(Type I), early stretched middle tensile shearing fault system(Type I-II), early stretched middle tensile shearing reverse late fault system(Type I-II-III). Type I-II and I-II-III are stretching by NW tensional stress in Nantun group ,which afford tectonic framework for syngenesis buried hill and epigenetic buried hill. Type I make buried hills complicated .It is also favorable to ancient geomorphological buried hill in the fault less affected zones. Although they formed cracks dense zone easier, Type I-II and I-II-III fault system damage the reservoir which is not conducive to " hydrocarbon-supplying window " formation; Type I fault system have less promotion on the development of the buried hill reservoir, while it is conducive to hydrocarbon accumulation as the block boundary in buried hill hydrocarbon. Fault formed source rocks two kinds for hydrocarbon mode: unidirectional and bidirectional, which formed two reservoir-forming pattern: Unidirectional transportation hydrocarbon of weathering crust or hydrocarbon of fracture damage zones and bidirectional transportation hydrocarbon of weathering crust or hydrocarbon of fracture damage zones.


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