Uplift-related hydrocarbon accumulations: the release of natural gas from groundwater

Cramer, Bernhard; Schlömer, Stefan; Poelchau, H. S.

doi:10.1144/gsl.sp.2002.196.01.24

Cited by 10 publications

(8 citation statements)

References 17 publications

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“…The third mechanism is that the process of hydraulic fracturing generates new fractures or enlarges existing ones above the target shale formation, increasing the connectivity of the fracture system. The reduced pressure following the fracturing activities could release methane in solution, leading to methane exsolving rapidly from solution (29), allowing methane gas to potentially migrate upward through the fracture system.…”

Section: Resultsmentioning

confidence: 99%

Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing

Osborn¹,

Vengosh²,

Warner³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

1,087

825

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Directional drilling and hydraulic-fracturing technologies are dramatically increasing natural-gas extraction. In aquifers overlying the Marcellus and Utica shale formations of northeastern Pennsylvania and upstate New York, we document systematic evidence for methane contamination of drinking water associated with shalegas extraction. In active gas-extraction areas (one or more gas wells within 1 km), average and maximum methane concentrations in drinking-water wells increased with proximity to the nearest gas well and were 19.2 and 64 mg CH 4 L −1 (n ¼ 26), a potential explosion hazard; in contrast, dissolved methane samples in neighboring nonextraction sites (no gas wells within 1 km) within similar geologic formations and hydrogeologic regimes averaged only 1.1 mg L −1 (P < 0.05; n ¼ 34). Average δ 13 C-CH 4 values of dissolved methane in shallow groundwater were significantly less negative for active than for nonactive sites (−37 AE 7‰ and −54 AE 11‰, respectively; P < 0.0001). These δ 13 C-CH 4 data, coupled with the ratios of methane-to-higher-chain hydrocarbons, and δ 2 H-CH 4 values, are consistent with deeper thermogenic methane sources such as the Marcellus and Utica shales at the active sites and matched gas geochemistry from gas wells nearby. In contrast, lower-concentration samples from shallow groundwater at nonactive sites had isotopic signatures reflecting a more biogenic or mixed biogenic/ thermogenic methane source. We found no evidence for contamination of drinking-water samples with deep saline brines or fracturing fluids. We conclude that greater stewardship, data, andpossibly-regulation are needed to ensure the sustainable future of shale-gas extraction and to improve public confidence in its use.groundwater | organic-rich shale | isotopes | formation waters | water chemistry

show abstract

Section: Resultsmentioning

confidence: 99%

Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing

Osborn¹,

Vengosh²,

Warner³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

1,087

825

View full text Add to dashboard Cite

show abstract

“…The upward transport of gases is theoretically possible, including pressure-driven flow through open, dry fractures and pressure-driven buoyancy of gas bubbles in aquifers and water-filled fractures (44,45). Reduced pressures after the fracturing activities could also lead to methane exsolving rapidly from solution (46). If methane were to reach an open fracture pathway, however, the gas should redissolve into capillary-bound water and/ or formation water, especially at the lithostatic and hydrostatic pressures present at Marcellus depths.…”

Section: Resultsmentioning

confidence: 99%

Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction

Jackson

Vengosh²,

Darrah³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

502

475

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Horizontal drilling and hydraulic fracturing are transforming energy production, but their potential environmental effects remain controversial. We analyzed 141 drinking water wells across the Appalachian Plateaus physiographic province of northeastern Pennsylvania, examining natural gas concentrations and isotopic signatures with proximity to shale gas wells. Methane was detected in 82% of drinking water samples, with average concentrations six times higher for homes <1 km from natural gas wells (P = 0.0006). Ethane was 23 times higher in homes <1 km from gas wells (P = 0.0013); propane was detected in 10 water wells, all within approximately 1 km distance (P = 0.01). Of three factors previously proposed to influence gas concentrations in shallow groundwater (distances to gas wells, valley bottoms, and the Appalachian Structural Front, a proxy for tectonic deformation), distance to gas wells was highly significant for methane concentrations (P = 0.007; multiple regression), whereas distances to valley bottoms and the Appalachian Structural Front were not significant (P = 0.27 and P = 0.11, respectively). Distance to gas wells was also the most significant factor for Pearson and Spearman correlation analyses (P < 0.01). For ethane concentrations, distance to gas wells was the only statistically significant factor (P < 0.005). Isotopic signatures (δ 13 C-CH 4 , δ 13 C-C 2 H 6 , and δ 2 H-CH 4 ), hydrocarbon ratios (methane to ethane and propane), and the ratio of the noble gas 4 He to CH 4 in groundwater were characteristic of a thermally postmature Marcellus-like source in some cases. Overall, our data suggest that some homeowners living <1 km from gas wells have drinking water contaminated with stray gases.carbon, hydrogen, and helium isotopes | groundwater contamination | geochemical fingerprinting | fracking | hydrology and ecology

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“…Such uplift movements may have a strong effect on the petroleum systems by changing the temperature and decreasing the pore pressure within the sediments. The most important effect of uplift on hydrocarbon distribution is the release of formerly dissolved gas from the pore water leading to new accumulations of natural gas (Cramer et al, 1999(Cramer et al, , 2001.…”

Section: Influence Of Cyclic Glaciations On Petroleum Systemsmentioning

confidence: 99%

pT-effects of Pleistocene glacial periods on permafrost, gas hydrate stability zones and reservoir of the Mittelplate oil field, northern Germany

Grassmann

Cramer

Delisle

et al. 2010

Marine and Petroleum Geology

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Uplift-related hydrocarbon accumulations: the release of natural gas from groundwater

Cited by 10 publications

References 17 publications

Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing

Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing

Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction

pT-effects of Pleistocene glacial periods on permafrost, gas hydrate stability zones and reservoir of the Mittelplate oil field, northern Germany

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