Organic-Rich Source Rocks of Pennsylvanian Age in the Paradox Basin of Utah and Colorado
Organic-Rich Source Rocks of Pennsylvanian Age in the Paradox Basin of Utah and Colorado
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犹他州和科罗拉多州悖论盆地宾夕法尼亚时代富含有机物的烃源岩
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发表时间：
1984
期刊：
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通讯作者：
T. Ging
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作者：
R. Hite;D. Anders;T. Ging
犹他州东南部和科罗拉多州西南部的悖论盆地包含一层厚厚的宾夕法尼亚时代的岩石序列，其中包括许多富含有机物的黑色页岩。其中最丰富的页岩与一系列蒸发碳酸盐旋回有关，是该盆地重要的烃源岩。最近，在能源部的两个岩心孔中对整个宾夕法尼亚-宾夕法尼亚段进行了取样。其中一个岩心孔，即位于犹他州圣胡安县R. 21 E. T. 30 S. 21段的Gibson Dome No. 1 (GD1)，提供了本报告中使用的大部分样品。Paradox黑色页岩由粘土大小的石英和长石、各种粘土矿物以及高比例的方解石和白云石组成。这些岩石中的有机碳含量变化很大，从0.5到13.0%不等。蒸发碳酸盐旋回中的页岩在横向上呈前三角洲相，为位于盆地东南边缘的银吨扇三角洲的一部分。尽管黑色页岩沉积于缺氧-蒸发环境，但热解和萃取数据表明其含有I1型和111型混合干酪根。这些页岩的显微组织中镜质组的丰富程度有些出乎意料，这表明与来自西尔弗顿三角洲的流体流入有关的大量土质物质的贡献。页岩中的镜质组反射率值（RO）被强烈抑制，在某些样品中，RO <0.50%，而这些样品的碳氢化合物含量高达16oo ppm。其中一种重要的页岩，被称为“哥特”，位于盆地南部的许多生产碳酸盐岩储层之下。在GP1的位置，“哥特式”有32英尺（9.7米）厚，每英亩至少产生4970桶石油。该页岩在Silverton扇三角洲复群附近增厚至160英尺（48.7米），可能与多孔三角洲前缘和分流河道砂岩储层夹层。这种舌间关系预示着一个潜在的石油勘探目标；然而。在盆地的这一部分，页岩中干酪根的质量和数量可能会下降。
The Paradox basin of southeast Utah and southwest Colorado contains a thick sequence of rocks of Pennsylvan- ian age which include numerous organic-rich black shales. The richest of these shales are associated with a series of evaporitecarbonafe cycles and form the important petroleum source rocks of this basin. Recently the entire Pennsyl- vanian interval was sampled in two Department of Energy core holes. One of these core holes, the Gibson Dome No. 1 (GD1) in sec. 21, T. 30 S., R. 21 E., San Juan County, Utah, provided most of the samples used in this report. The Paradox black shales consist of clay-sized quartz and feldspar, various clay minerals, and a high percentage of calcite and dolomite. The organic carbon content in these rocks is highly variable ranging from about 0.5 to 13.0 weight percent. Shales in the evaporitecarbonate cycles appear to grade laterally into a prodelta facies, which is part of the Silver- ton fan delta, located on the southeast margin of the basin. Although the black shales were deposited in an euxinic- evaporitic environment, pyrolysis and extraction data suggests they contain a mixture of type I1 and 111 kerogen. The somewhat Unexpected abundance of vitrinite in the macerals of these shales suggests a large contribution of terres- trial material associated with fluviatile influxes from the Silverton delta. Vitrinite reflectance values (RO) in the shales are strongly suppressed and are <0.50%in some samples that have generated as much as 16,ooO ppm hydrocarbons. One of the important source shales, known as the "Gothic," underlies many of the producing carbonate reservoirs in the southern part of the basin. At the GP1 location the "Gothic" is 32 ft (9.7 m) thick and has generated at least 4,970 bbls of oil per acre. This shale thickens to over 160 ft (48.7 m) near the Silverton fan delta complex where it may intertongue with porous delta front and distributary channel sandstone reservoirs. This intertonguing relationship sug- gests a potential petroleum exploration target; however. the quality and quantity of kerogen in the shale may decrease in this part of the basin.