Lu S.,Northeast Petroleum University |
Lu S.,Province Key Laboratory of Petroleum Accumulation Mechanism and Resource Prediction |
Chen F.,Northeast Petroleum University |
Li J.,Northeast Petroleum University |
And 6 more authors.
Petroleum Science | Year: 2012
The theory of "source rock control" has evolved from source-rock-control hydrocarbon accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality source-rock-control hydrocarbon accumulation. However, there are problems, such as whether high-quality source rocks exist or not? What high-quality source rocks are, and how to identify them, are yet to be agreed upon. Aimed at this issue of concern to explorationists, and taking the Beier Sag in the Hailaer Basin as an example, this paper defines the high-quality source rocks and the lower limit for evaluation of high-quality source rocks, by using the inflection point on the relationship curve of hydrocarbon (oil) expulsion, which is calculated by the material balance principle, versus total organic carbon (TOC). The results show that when TOC is low, all source rocks have limited hydrocarbon expulsion and slow growth rate, thus they cannot be high-quality source rocks. However, when TOC rises to some threshold, hydrocarbon expulsion increases significantly with TOC. This inflection point should be the lower limit of high-quality source rocks: those with TOC greater than the inflection-point value are high-quality source rocks. In addition, the lower limit of high-quality source rocks is also related to the type and maturity of organic matters in the source rocks, as well as the mineral components of the source rocks affecting the residual hydrocarbons. Theoretically, the lower limit of high-quality source rocks depends on geological conditions rather than being a constant value. However, for the sake of simplicity and practicability, in this paper TOC=2.0% is regarded as the lower limit of high-quality source rocks. The examination of such standard in the work area indicates that the high-quality source rocks in members K 1n 2 and K 1n 1 of the Nantun formation contribute 76% and 82% to oil generation, and 96% and 91% to oil expulsion, respectively. The distribution of high-quality source rocks is also closely related to the distribution of hydrocarbon reservoirs in the region, demonstrating that high-quality source rocks control hydrocarbon accumulation. © 2012 China University of Petroleum (Beijing) and Springer-Verlag Berlin Heidelberg.
Chen F.-W.,Northeast Petroleum University |
Chen F.-W.,Province Key Laboratory of Petroleum Accumulation Mechanism and Resource Prediction |
Lu S.-F.,Northeast Petroleum University |
Lu S.-F.,Province Key Laboratory of Petroleum Accumulation Mechanism and Resource Prediction |
And 4 more authors.
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2012
By analyzing the difference of crude oil maturity, preferred direction of hydrocarbon migration, distribution of hydrocarbon, shielded effect of trap on hydrocarbon migration, and geochemical characteristics of source rocks, and by combining with chemistry kinetic method, the oil-source of Changchunling anticline in Northern Songliao Basin, and the resource of its oil-source area were studied. The results show that the crude oil maturity of Changchunling anticline is similar to that of Wangfu depression, but significantly lower than that of Sanzhao depression and Chaoyanggou terrace. Changchunling anticline is on the preferred direction of hydrocarbon migration from Wangfu depression. The distribution of crude oil is around Wangfu depression on level. Chaoyanggou terrace shields the hydrocarbon migration from Sanzhao depression to Changchunling anticline. The crude oil of Changchunling anticline comes mainly from Wangfu depression. The source rocks of Qingshankou formation in Wangfu depression are high abundance of organic matter, good type, but low maturity. The amount of oil and gas generation from Qingshankou formation are 13.6×10 11 t and 4.4×10 8 m 3 in Wangfu depression, and the resource of oil and gas are (0.68-2.72) ×10 8 t and (0.022-0.088) ×10 11 m 3 respectively.