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| | part = Predicting the occurrence of oil and gas traps | | | part = Predicting the occurrence of oil and gas traps |
| | chapter = Evaluating top and fault seal | | | chapter = Evaluating top and fault seal |
− | | frompg = 10-1 | + | | frompg = 10-46 |
− | | topg = 10-94 | + | | topg = 10-46 |
| | author = Grant M. Skerlec | | | author = Grant M. Skerlec |
| | link = http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm | | | link = http://archives.datapages.com/data/specpubs/beaumont/ch10/ch10.htm |
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| | isbn = 0-89181-602-X | | | isbn = 0-89181-602-X |
| }} | | }} |
− | Loss of top seal integrity by high [[strain]] and [[Fracture|fracturing]] is an important cause of dry holes and partially filled traps.<ref name=ch10r70>Skerlec, G., M., 1982, Risking top seals in the Central Graben: Exxon Production Research Company internal report.</ref><ref name=ch10r71>Skerlec, G., M., 1990, SEALS: A short course for risking top seal and fault seal: Franklin, Pennsylvania, SEALS International, 600 p.</ref> Although fracturing is commonly predicted from [[stress]], the advantage of strain analysis is that it provides a practical tool prior to drilling for evaluating prospects using [[seismic data]]. | + | Loss of top seal integrity by high [[Wikipedia:Deformation(mechanics)|strain]] and [[Fracture|fracturing]] is an important cause of [[dry hole]]s and partially filled traps.<ref name=ch10r70>Skerlec, G., M., 1982, Risking top seals in the Central Graben: Exxon Production Research Company internal report.</ref><ref name=ch10r71>Skerlec, G., M., 1990, SEALS: A short course for risking top seal and fault seal: Franklin, Pennsylvania, SEALS International, 600 p.</ref> Although fracturing is commonly predicted from [[Wikipedia:Stress (mechanics)|stress]], the advantage of strain analysis is that it provides a practical tool prior to drilling for evaluating prospects using [[seismic data]]. |
| | | |
| ==Rates of leakage== | | ==Rates of leakage== |
− | Even a small amount of [[Fracture|fracturing]] can result in staggering leakage rates. The volume of hydrocarbon that could be lost from a typical North Sea field, assuming a fractured top seal with a relatively low fracture [[permeability]] of only 0.05 md, is more than 100 billion bbl/m.y..<ref name=ch10r71 />). Fracture permeability can be as high as tens of darcys (<ref name=ch10r80>Stearns, D., W., Friedman, M., 1972, Reservoirs in fractured rock: AAPG Memoir 16, p. 82–106.</ref> and leakage rates consequently can be much higher. | + | Even a small amount of [[Fracture|fracturing]] can result in staggering leakage rates. The volume of hydrocarbon that could be lost from a typical North Sea field, assuming a fractured top seal with a relatively low fracture [[permeability]] of only 0.05 md, is more than 100 billion bbl/m.y.<ref name=ch10r71 /> Fracture permeability can be as high as tens of darcys<ref name=ch10r80>Stearns, D., W., Friedman, M., 1972, Reservoirs in fractured rock: AAPG Memoir 16, p. 82–106.</ref> and leakage rates consequently can be much higher. |
| | | |
| Natural seeps confirm these high rates of hydrocarbon loss. The [[Palos Verde fault]] in Santa Monica Bay, California, seeps oil at the rate of 10–15 bbl/d or more than 5 billion bbl/m.y. The [[Coal Point seep]] in the Santa Barbara Channel, California, is leaking 50–70 bbl/d or more than 25 billion bbl/m.y.<ref name=ch10r95>Wilkinson, E., R., 1971, California offshore oil and gas seeps: California Oil Fields–Summary Operations, vol. 57, no. 1, p. 5–28.</ref> | | Natural seeps confirm these high rates of hydrocarbon loss. The [[Palos Verde fault]] in Santa Monica Bay, California, seeps oil at the rate of 10–15 bbl/d or more than 5 billion bbl/m.y. The [[Coal Point seep]] in the Santa Barbara Channel, California, is leaking 50–70 bbl/d or more than 25 billion bbl/m.y.<ref name=ch10r95>Wilkinson, E., R., 1971, California offshore oil and gas seeps: California Oil Fields–Summary Operations, vol. 57, no. 1, p. 5–28.</ref> |
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| [[Category:Predicting the occurrence of oil and gas traps]] | | [[Category:Predicting the occurrence of oil and gas traps]] |
| [[Category:Evaluating top and fault seal]] | | [[Category:Evaluating top and fault seal]] |
| + | [[Category:Treatise Handbook 3]] |