The maximum palaeotemperature of oil-bearing sandstones in the UpperTriassic in the eastern Ordos basin has been determined by using many methods including thevitrinite reflectance, fluid inclusion, apatite fission tr...The maximum palaeotemperature of oil-bearing sandstones in the UpperTriassic in the eastern Ordos basin has been determined by using many methods including thevitrinite reflectance, fluid inclusion, apatite fission track, illite crystallinity, chlorite polytypeand diagenetic change of authigenic minerals. The thermal gradient in the Late Mesozoic wasabout 2.9-3.0℃/100m. The Upper Triassic was in a mature stage of organic matter andhydrocarbon began to be generated and migrated during this period. The palaeotemperatures ofoil-bearing sandstones were in the range of 88-110℃; those for the generation and migrationof oil ranged from 112 to 122℃. The thickness of the denuded strata overlying the UpperTriassic was 2465-2750m. The present burial depth of oil-bearing sandstones is generally from400 to 1200m. At a depth of ca. 1900m, the temperature may reach 140℃. Below this depth,organic matter was supermature and mainly generated gas.展开更多
Sequential extraction was performed on two oil sandstones from the Upper Carboniferous oil columns of TZ401 well. The free oils of these two oil sandstones and a crude oil from the Lower Carboniferous oil column of th...Sequential extraction was performed on two oil sandstones from the Upper Carboniferous oil columns of TZ401 well. The free oils of these two oil sandstones and a crude oil from the Lower Carboniferous oil column of this well have low ratios of C28/（C27 ＋ C28＋ C29） steranes and gammacerane/C31 hopanes, ranging of 0.11-0.16 and 0.09-0.15, respectively, similar to those from the Middle-Upper Ordovician source rock. However, these two ratios for the adsorbed and inclusion oils of these two oil sandstones are relatively high, ranging of 0.29-0.31 and 0.26-0.40, respectively, similar to those of the Cambrian-Lower Ordovician source rock. This result demonstrates that the initial oil charging the reservoirs was derived from the Cambrian-Lower Ordovician source rock, whereas the later charging oil was derived from the Middle-Upper Ordovician source rock.展开更多
基金This study was supported by the cooperative research project of the Petroleum Administration of the Yanchang Oil Field,Shaanxi,and the Northwest University.
文摘The maximum palaeotemperature of oil-bearing sandstones in the UpperTriassic in the eastern Ordos basin has been determined by using many methods including thevitrinite reflectance, fluid inclusion, apatite fission track, illite crystallinity, chlorite polytypeand diagenetic change of authigenic minerals. The thermal gradient in the Late Mesozoic wasabout 2.9-3.0℃/100m. The Upper Triassic was in a mature stage of organic matter andhydrocarbon began to be generated and migrated during this period. The palaeotemperatures ofoil-bearing sandstones were in the range of 88-110℃; those for the generation and migrationof oil ranged from 112 to 122℃. The thickness of the denuded strata overlying the UpperTriassic was 2465-2750m. The present burial depth of oil-bearing sandstones is generally from400 to 1200m. At a depth of ca. 1900m, the temperature may reach 140℃. Below this depth,organic matter was supermature and mainly generated gas.
基金supported by the National Basic Research Pro-gram of China (No. 2005CB422102)the National Natural Science Foundation of China (No. 40673014)
文摘Sequential extraction was performed on two oil sandstones from the Upper Carboniferous oil columns of TZ401 well. The free oils of these two oil sandstones and a crude oil from the Lower Carboniferous oil column of this well have low ratios of C28/（C27 ＋ C28＋ C29） steranes and gammacerane/C31 hopanes, ranging of 0.11-0.16 and 0.09-0.15, respectively, similar to those from the Middle-Upper Ordovician source rock. However, these two ratios for the adsorbed and inclusion oils of these two oil sandstones are relatively high, ranging of 0.29-0.31 and 0.26-0.40, respectively, similar to those of the Cambrian-Lower Ordovician source rock. This result demonstrates that the initial oil charging the reservoirs was derived from the Cambrian-Lower Ordovician source rock, whereas the later charging oil was derived from the Middle-Upper Ordovician source rock.
