The hydrocarbon generation and expulsion features of source rocks and tight oil potential of the second member of the Qiketai Formation, Shengbei area in the Turpan–Hami Basin, NW China

Abstract

Significant progress in tight oil exploration has been reported in the second member of the Qiketai Formation (J2q2) in the Shengbei area of the Turpan–Hami Basin. Geochemical analyses were conducted to assess the quality of the J2q2 source rocks. The improved hydrocarbon generation potential method was utilized to quantify the hydrocarbon generation and expulsion features of the source rocks. The results showed that J2q2 source rocks were deposited in a reduced lacustrine setting with a high palaeoproductivity. The J2q2 source rocks are widely distributed (approximately 1,000 km2) and have a thickness that varies from 50 to 130 m. Moreover, they can be identified as a set of high‐quality source rocks (thermally mature rocks with Ro values >0.5%, consisting mainly of types I and II kerogen and possessing an average total organic carbon content of 2.68%). The oil–source correlation results reveal that the source of crude oil in the studied area is J2q2. The improved hydrocarbon generation potential method is established for different kerogen types to limit the influence of the kerogen type on the calculation. The hydrocarbon expulsion threshold of the type I model is located at Ro = 0.6%. The type II kerogen rocks have different characteristics, and the hydrocarbon expulsion threshold is located at Ro = 0.62%. The maximum hydrocarbon generation and expulsion intensities are 700 × 104 t/km2 and 400 × 104 t/km2, respectively. The hydrocarbon generation and expulsion amount of the J2q2 source rocks are 21.4 × 108 t and 12.3 × 108 t, respectively. The tight oil potential of the J2q2 tight oil in the Shengbei area is 4.09 × 108 t. The SB10 and SB6 well areas are favourable J2q2 tight oil exploration areas in the Shengbei area. The SB10 well area has the highest hydrocarbon generation and expulsion intensities in the study area and is the best tight oil exploration target.

Sedimentary Organic Facies Division and Hydrocarbon-Generation Potential of Source Rocks in Coal-Bearing Strata─A Case Study of the Upper Paleozoic in Huanghua Depression, Bohai Basin, China

“…Hydrogen-rich organic macerals are mainly xyloplasts, keratinites, and resinites, and hydrogen-rich stromal vitrinites. 47 − 49 The composition characteristics of this maceral are very similar to those of Upper Paleozoic coal in Huanghua Depression. On the whole, organic facies is also dominated by open water organic facies and shallow marsh forest organic facies.…”

“…The Middle–Lower Jurassic coal measures in the Tu Ha Basin are considered to be typical coal-to-oil basins in which the volume fraction of vitrinite is generally 60–80%, and the volume fractions of inertinite and exinite are 10–25 and 5–15%, respectively. Hydrogen-rich organic macerals are mainly xyloplasts, keratinites, and resinites, and hydrogen-rich stromal vitrinites. − The composition characteristics of this maceral are very similar to those of Upper Paleozoic coal in Huanghua Depression. On the whole, organic facies is also dominated by open water organic facies and shallow marsh forest organic facies.…”

Key factors controlling the accumulation of oil reservoir in the Gaosheng area of Western Depression, Liaohe Basin, Northeastern China

“…According to Section 4.1 of the results, the Es3 and Es4 source rocks have high abundance, good types, and their Ro are at the oil generation window, indicating that the source rocks have the potential to provide a large amount of crude oil and thus form large reservoirs. High hydrocarbon generation intensity is conducive to reservoir formation and the value of large reservoirs is generally greater than 350 × 10 4 t/km 2 (Hu et al, 2017;Feng et al, 2021;Song et al, 2021). The hydrocarbon generating intensity of Es4 is generally 5 × 10 6 -10 × 10 6 t/km 2 , and that of Es3 is generally greater than 5 × 10 6 -15 × 10 6 t/km 2 , which also indicates that the hydrocarbon generating potential of source rocks is good (Wu, 2012).…”

“…The distribution of tight oil in China is characterized by a wide range, multiple blocks, and large series span. In addition, tight sandstone in the Quang 4th member Formation in Songliao Basin (Huang et al, 2017), Jurassic Formation of the Tuha Basin (Feng et al, 2021), Yanchang Formation in Ordos Basin (Xu et al, 2017), Cretaceous tight limestone of the Jiuquan Basin (Chen et al, 2018) and the dolomites of Permian Lucaogou Formation in Junggar Basin (Liu et al, 2023) all have geological conditions for forming tight oil reservoir. In terms of geological background, source rock quality, reservoir quality, formation overpressure, sourcereservoir communication and crude oil quality, the Bakken oil formation in Williston Basin in North America is comparable to the Bakken and Eagle Ford tight oil in North America.…”