Petroleum Science >2012,??Issue 1:??10-17 DOI: https://doi.org/10.1007/s12182-012-0176-y
Identification of the lower limit of high-qualitysource rocks and its relation to hydrocarbonaccumulation— Taking the Beier Sag in theHailaer Basin as an example Open?Access
文章信息
College of Geosciences, Northeast Petroleum University, Heilongjiang 163318, China;Province Key Laboratory of Petroleum Accumulation Mechanism and Resource Prediction, Heilongjiang 163318, China;College of Geosciences, Northeast Petroleum University, Heilongjiang 163318, China;College of Geosciences, Northeast Petroleum University, Heilongjiang 163318, China;Province Key Laboratory of Petroleum Accumulation Mechanism and Resource Prediction, Heilongjiang 163318, China;College of Geosciences, Northeast Petroleum University, Heilongjiang 163318, China;Province Key Laboratory of Petroleum Accumulation Mechanism and Resource Prediction, Heilongjiang 163318, China;College of Geosciences, Northeast Petroleum University, Heilongjiang 163318, China;The Halaer Exploratory Development Headquarters, Daqing Oilfield Company Ltd., Heilongjiang 163000, China;College of Geosciences, Northeast Petroleum University, Heilongjiang 163318, China
文章摘要
accumulation, to effective source-rock-control hydrocarbon accumulation, and to high-quality sourcerock-
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 K1n2 and K1n1
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.
关键词
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High-quality source rocks, material balance, oil generation, oil expulsion, hydrocarbongeneration potential, Beier Sag