Molecular correlation of crude oils and oil components from reservoir rocks in the Tazhong and Tabei uplifts of the Tarim Basin, China

Organic geochemistry of Carboniferous source rocks and their generated oils from the Eastern Junggar Basin, NW China

“…(4) source rocks (Table 4, Figs. 4e, 6b-c and e-f), which can be mainly ascribed to higher maturities of C 1d source rocks than C 2b source rocks (e.g., Aquino Neto et al, 1983;Shi et al, 1988;Van Graas, 1990;Farrimond et al, 1999;Pan and Yang, 2000;Yu et al, 2011). (5) C 1d source rocks contain relatively higher concentrations of C 27 steranes and lower concentrations of C 29 steranes compared with C 2b source rocks (Table 4, Figs.…”

“…The free, adsorbed and inclusion oils were obtained from oilcontaining reservoir rocks by sequential extraction as described previously (Pan and Liu, 2009;Yu et al, 2011). Briefly, each core was crushed and sieved to obtain about 200 g of 0.10-0.30 mm size fraction.…”

“…In the present study, we document organic geochemical characteristics of these two sets of Carboniferous source rocks and oils in the Eastern Junggar Basin based on bulk and molecular parameters, and carbon isotopic compositions of individual n-alkanes. In addition, as demonstrated by previous studies, analysis of oil-bearing fluid inclusions and sequential extraction of oil-containing reservoir rocks are effective approaches to reveal geochemical signatures of the initial oil charges (Karlsen et al, 1993;Wilhelms et al, 1996;George et al, 1997George et al, , 1998George et al, , 2004George et al, , 2008Schwark et al, 1997;Jones and Macleod, 2000;Leythaeuser et al, 2000Leythaeuser et al, , 2007Pan and Yang, 2000;Pan et al, , 2003Pan et al, , 2005Pan et al, , 2007Gong et al, 2007;Yu et al, 2011Yu et al, , 2012. A large set of oil-containing volcanic reservoir rocks from the Kelameili gasfield were also analyzed to evaluate the source variations during the reservoir filling.…”

Isotopic compositions and biomarkers in crude oils from the Tarim Basin: Oil maturity and oil mixing

“…The occurrence and formation of marine oils and reservoir bitumen in this basin attracted many geochemists' attention in the past decade due to the long, complex and deep burial geological history of oils Li et al, 2000Li et al, , 2010Zhang et al, 2000Zhang et al, , 2011Sun et al, 2003;Jia et al, 2008Jia et al, , 2010Cai et al, 2009;Pan and Liu, 2009;Yu et al, 2011Yu et al, , 2012. The two old marine oil source units identified in the basin are the Cambrian-Lower Ordovician and Middle-Upper Ordovician strata Zhang et al, 2000).…”

“…Multiple oil generation and filling stages have been proposed as the mechanism of diverse oil formation, e.g., normal, light, waxy and heavy oils occurring in the basin Gong et al, 2007;Wang et al, 2008;Pan and Liu, 2009;Jia et al, 2010;Li et al, 2010;Yu et al, 2011). Many publications documented that there are large variations in the maturity of those oils Pan and Liu, 2009;Yu et al, 2011) and secondary alteration processes also have been reported, including moderate to severe biodegradation (Wang et al, 2008;Pan and Liu, 2009;Jia et al, 2010), and gas washing or migration fractionation resulting in wax precipitation (Ma et al, 1996;Zhang, 2000;Zhang et al, 2011). Although many studies have been carried out, the understanding of the oil source, maturity and oil mixing in the Tarim Basin was not conclusive, partly because limited source rocks in the basin had been revealed by exploration practices.…”