% d'eau utilisée versus la consommation totale: 0.19% en Pennsylvanie

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En Pennsylvanie, la quantité d’eau totale utilisée pour la fracturation hydraulique correspond à 0.19% de l’eau totale consommée par l’Etat.

Pennsylvania’s annual total water consumption is approximately 3.6 trillion gallons, of which the shale gas industry withdraws about 0.19% for hydraulic fracturing.

Mais pour prendre un cas encore plus concret et réaliste pour bien comprendre et mettre en perspective les quantités d’eau utilisées par l’industrie par rapport à la consommation globale, le cas du shale Eagle Ford (Texas) est probablement le meilleur exemple.

Au Texas, Etat reconnu pour sa forte activité de forage hydraulique, ses périodes de sécheresses importantes et une région où le degré de renouvellement naturel des eaux est le plus faible, Eagle Ford est reconnu comme le basin le plus prolifique de tous les basins en Amérique. Ses activités de forages sont élevées.

Considérant ces 3 contraintes extrêmes combinées, il est établie que pour toute la durée de vie du développement de ce shale, Eagle Ford ne consommera pas plus de 2% des eaux de consommation (incluant ceux pour l’agriculture et celles des municipalités). On parle ici d’un cas extrême. Pour la Pennsylvanie, ce ratio est de 0.19%.

An instructive case to make a realistic, worst-case, assessment the magnitude of water consumption for producing shale gas is the Eagle Ford shale play. Of all the current significant shale gas production areas in North America today, the Eagle Ford has the highest reliance on largely non-renewable water and has the driest climate. Brownlow (2010) has estimated the total consumption of water over the lifetime of the Eagle Ford play will be 300,000 acre-feet. The present day pumping rate (for this area of the Carrizo aquifer), for all uses other than shale gas, has been estimated as 275,000 acre-feet per year (Brownlow, 2010). If this rate of agricultural and municipal pumpage holds constant over the life of the play (estimated by Nicot and Scanlon, 2012 as on the order of fifty years), then the usage for shale gas will be on the order of 2% of the total.

Richard Paiement

il y a 3 mois

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Pour une région reconnue pour ses épisodes de sécheresse intenses, provenant d’un organisme règlementaire majeur, recevant aussi l’aval de 2 organismes environnementaux (le Sierra Club et le Evergreen Underground Water Conservation), et concernant le shale play le plus actif des Etats-Unis, l’usage de l’eau par l’industrie au Québec ne devrait pas être un problème.

Water Supply Adequate to Support Eagle Ford Activity - Texas Railways Commission

Data presented to the group indicated that drilling and completions in the Eagle Ford shale account for approximately 6% of the water demand in South Texas, while irrigation accounts for 64% and municipal use accounts for 17%.

As a whole, the oil and gas industry has reduced the amount of water used to hydraulically fracture wells, with an average use of approximately 11 acre-feet of water used to complete each well, down from the estimated 15 acre-feet previously used, a 27% reduction.

"I am pleased industry has made improvements in reducing the amount of water used in the hydraulic fracturing process, and we look forward to working in a cooperative manner with all task force stakeholders to continue improving the process," said task force member Teresa Carrillo, executive committee member of Sierra Club’s Lone Star chapter.

Water levels had declined due to the current drought. However, groundwater pumping for oil and gas drilling and completion is not viewed "as a significant contribution to the decline in water levels, when compared to overall pumping," said task force member Mike Mahoney, general manager for the Evergreen Underground Water Conservation District.

http://www.rigzone.com/news/article.asp?a_id=114624&hmpn=1