The Search for a Source Rock for the Giant Tar Sand Triangle Accumulation, Southeastern Utah
The Search for a Source Rock for the Giant Tar Sand Triangle Accumulation, Southeastern Utah
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寻找犹他州东南部巨型焦油砂三角堆积的源岩
DOI：
10.1306/00aa9bd8-1730-11d7-8645000102c1865d
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发表时间：
1999
期刊：
影响因子：
3.5
通讯作者：
N. Naeser
中科院分区：
文献类型：
--
作者：
J. Huntoon;P. L. Hansley;N. Naeser
世界石油资源的很大一部分（约36%）包含在重油或焦油的积累中。在这些大型的降解石油矿床中，石油的储量只占积累时的一小部分。在许多这些矿床中，石油的来源是未知的，石油被认为是经过长距离迁移到油藏的。犹他州东南部的焦油砂三角区是美国最大的焦油砂堆积区，估计有63亿桶重油。该存款被认为是原来含有13-16十亿桶之前，生物降解，水洗，和侵蚀，已发生自中晚第三纪。石油的来源不明。焦油主要包含在下二叠统白色边缘砂岩中，但延伸到上覆层和下伏层的可渗透部分。石油被解释为在第三纪的某个时候迁移到白色边缘，当时地层深度约为3500 m。这一结论是基于对白色边缘砂岩流体包裹体分析、时间-温度重建和磷灰石裂变径迹模拟的综合。白色缘自生非铁白云石中原生流体包裹体的均一温度集中在85-90°C左右。流体包裹体与荧光含油包裹体共生，表明白云岩沉积与石油运移是同期的。埋藏重建表明，白色缘砂岩在60 ~ 24 Ma达到最大埋藏深度，在24 ~ 0 Ma达到最大埋藏深度后开始去顶。时间-温度模型表明，地层在最大埋藏期间经历了约35至40 Ma的85-90°C的温度。在24 Ma左右，就在去顶之前，达到了约105-110°C的最高地层温度。热模拟用于研究白色边缘石油的潜在烃源岩的历史。白色边缘石油最具吸引力的潜在来源包括以下一个或多个地层中的地层：元古宙Chuar群，位于焦油砂三角洲西南的地下;密西西比系Deseret石灰岩和等效地层的Delle磷酸盐岩段、二叠纪Kaibab石灰岩、三叠系Moenkopi地层的Sinbad石灰岩段和侏罗纪Arapien页岩，Twin Creek Limestone和卡梅尔组，位于焦油砂三角洲以西; Pennsylvanian Parkian Formation位于焦油砂三角洲以东的Parkian盆地; Permian Park City Formation位于焦油砂三角洲西北部。每一层都有很高的总有机碳含量，分布在足够广泛的地理区域，提供了大量的石油。所有地层中的生油层在被解释为发生向白色边缘迁移之前或期间达到热成熟。根据所有可用的数据，焦油砂三角区最有可能的来源似乎是密西西比州德塞雷特石灰岩的Delle磷酸盐岩段。Delle的二次迁移被解释为发生在白垩纪期间，在Sevier逆冲推覆期间。随后的第三次迁移到焦油砂三角储层被解释为发生在晚些时候，在第三纪中期Laramide变形。
A large proportion (about 36%) of the worlds oil resource is contained in accumulations of heavy oil or tar. In these large deposits of degraded oil, the oil in place represents only a fraction of what was present at the time of accumulation. In many of these deposits, the source of the oil is unknown, and the oil is thought to have migrated over long distances to the reservoirs. The Tar Sand triangle in southeastern Utah contains the largest tar sand accumulation in the United States, with 6.3 billion bbl of heavy oil estimated to be in place. The deposit is thought to have originally contained 13-16 billion bbl prior to the biodegradation, water washing, and erosion that have taken place since the middle-late Tertiary. The source of the oil is unknown. The tar is primarily contained within the Lower Permian White Rim Sandstone, but extends into permeable parts of overlying and underlying beds. Oil is interpreted to have migrated into the White Rim sometime during the Tertiary when the formation was at a depth of approximately 3500 m. This conclusion is based on integration of fluid inclusion analysis, time-temperature reconstruction, and apatite fission-track modeling for the White Rim Sandstone. Homogenization temperatures cluster around 85-90°C for primary fluid inclusions in authigenic, nonferroan dolomite in the White Rim. The fluid inclusions are associated with fluorescent oil-bearing inclusions, indicating that dolomite precipitation was coeval with oil migration. Burial reconstruction suggests that the White Rim Sand stone reached its maximum burial depth from 60 to 24 Ma, and that maximum burial was followed by unroofing from 24 to 0 Ma. Time-temperature modeling indicates that the formation experienced temperatures of 85-90°C from about 35 to 40 Ma during maximum burial. Maximum formation temperatures of about 105-110°C were reached at about 24 Ma, just prior to unroofing. Thermal modeling is used to examine the history of potential source rocks for the White Rim oil. The most attractive potential sources for White Rim oil include beds within one or more of the following formations: the Proterozoic Chuar Group, which is present in the subsurface southwest of the Tar Sand triangle; the Mississippian Delle Phosphatic Member of the Deseret Limestone and equivalent formations, the Permian Kaibab Limestone, the Sinbad Limestone Member of the Triassic Moenkopi Formation, and the Jurassic Arapien Shale, Twin Creek Limestone, and Carmel Formation, which are present west of the Tar Sand triangle; the Pennsylvanian Paradox Formation in the Paradox basin east of the Tar Sand triangle; and the Permian Park City Formation northwest of the Tar Sand triangle. Each formation has a high total organic carbon content and is distributed over a wide enough geographic area to have provided a huge volume of oil. Source beds in all of the formations reached thermal maturity at times prior to or during the time that migration into the White Rim is interpreted to have occurred. Based on all available data, the most likely source for the Tar Sand triangle appears to be the Mississippian Delle Phosphatic Member of the Deseret Limestone. Secondary migration out of the Delle is interpreted to have occurred during the Cretaceous, during Sevier thrusting. Subsequent tertiary migration into the Tar Sand triangle reservoir is interpreted to have occurred later, during middle Tertiary Laramide deformation.