?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=https%3A%2F%2Fepisodesplatform.eu%2Feprints%2F1679%2F&rft.title=The+Carboniferous+Bowland+Shale+gas+study%3A+geology+and+resource+estimation&rft.creator=Andrews%2C+I+J&rft.subject=Lancashire&rft.subject=Unconventional+hydrocarbon+extraction&rft.subject=Method+and+procesing&rft.description=The+assessment+of+shale+gas+resources+in+the+UK+is+in+its+infancy.+This+report+summarises+the+background+geological+knowledge+and+methodology+which+has+enabled+a+preliminary+in-place+gas+resource+calculation+to+be+undertaken+for+the+Bowland-Hodder+(Carboniferous)+shale+gas+play1%0D%0AMarine+shales+were+deposited+in+a+complex+series+of+tectonically+active+basins+across+central+Britain+during+the+Visean+and+Namurian+epochs+across+a+large+area+of+central+Britain+(Figure+1).%0D%0A2%0D%0AThe+marine+shales+attain+thicknesses+of+up+to+16%2C000+ft+(5000+m)+in+basin+depocentres+(i.e.+the+Bowland%2C+Blacon%2C+Gainsborough%2C+Widmerpool%2C+Edale+and+Cleveland+basins)%2C+and+they+contain+sufficient+organic+matter+to+generate+considerable+amounts+of+hydrocarbons.+Conventional+oil+and+gas+fields+around+most+of+these+basins+attest+to+their+capability+to+produce+hydrocarbons.+of+the+Carboniferous+(c.347-318+Ma).+In+all+of+these+basins%2C+deep-water+marine+shales+pass+laterally+into+shallow-water+shelf+limestones+and+deltaic+sandstones.+Contemporary+basins+extend+offshore+beneath+the+East+Irish+Sea+and+the+Southern+North+Sea.%0D%0AThe+organic+content+of+the+Bowland-Hodder+shales+is+typically+in+the+range+1-3%25%2C+but+can+reach+8%25.%0D%0AThe+maturity+of+the+Bowland-Hodder+shales+is+a+function+of+burial+depth%2C+heat+flow+and+time%2C+but+subsequent+uplift+complicates+this+analysis.+Where+they+have+been+buried+to+sufficient+depth+for+the+organic+material+to+generate+gas%2C+the+Bowland-Hodder+shales+have+the+potential+to+form+a+shale+gas+resource+analogous+to+the+producing+shale+gas+provinces+of+North+America+(e.g.+Barnett+Shale%2C+Marcellus+Shale).+Where+the+shales+have+been+less-deeply+buried%2C+there+is+potential+for+a+shale+oil+resource+(but%2C+as+yet%2C+there+is+inadequate+geotechnical+data+to+estimate+the+amount+of+oil+in-place).%0D%0AIn+this+study%2C+shales+are+considered+mature+for+gas+generation+(vitrinite+reflectance+%3E+1.1%25)+at+depths+greater+than+c.+9500+ft+(2900+m)+(where+there+has+been+minimal+uplift).+However%2C+central+Britain+has+experienced+a+complex+tectonic+history+and+the+rocks+here+have+been+uplifted+and+partially+eroded+at+least+once+since+Carboniferous+times.+Because+of+this%2C+the+present-day+depth+to+the+top+of+the+gas+window+is+dependent+on+the+amount+of+uplift%2C+and+can+occur+significantly+shallower+than+9500+ft.%0D%0AThe+total+volume+of+potentially+productive+shale+in+central+Britain+was+estimated+using+a+3D+geological+model+generated+using+seismic+mapping%2C+integrated+with+outcrop+and+deep+borehole+information.+This+volume+was+truncated+upwards+at+a+depth+of+5000+ft+(1500+m)+below+land+surface+(a+suggested+US+upper+limit+for+thermogenic+shale+gas+production)+or+the+depth+at+which+the+shale+is+mature+for+gas+generation+(whichever+was+the+shallowest).%0D%0AThe+volume+of+potentially+productive+shale+was+used+as+one+of+the+input+parameters+for+a+statistical+calculation+(using+a+Monte+Carlo+simulation)+of+the+in-place+gas+resource+(see+Appendix+A).&rft.publisher=British+Geological+Survey&rft.date=2013&rft.type=Reports&rft.type=NonPeerReviewed&rft.identifier=++Andrews%2C+I+J++(2013)+The+Carboniferous+Bowland+Shale+gas+study%3A+geology+and+resource+estimation.++Documentation.+British+Geological+Survey%2C+London+UK.+++++&rft.relation=https%3A%2F%2Fwww.gov.uk%2Fgovernment%2Fpublications%2Fbowland-shale-gas-study