Corporate Strategic Research, ExxonMobil Research and Engineering, 1545 Route 22 East, Annandale, NJ, 08801, USA.
Sofinnova Partners, 7-11 Boulevard Haussmann, Paris, 75009, France.
Sci Rep. 2020 Feb 3;10(1):1669. doi: 10.1038/s41598-020-58390-z.
Induced polarization (IP) mapping has gained increasing attention in the past decades, as electrical induced polarization has been shown to provide interesting signatures for detecting the presence of geological materials such as clay, ore, pyrite, and potentially, hydrocarbons. However, efforts to relate complex conductivities associated with IP to intrinsic physical properties of the corresponding materials have been largely empirical. Here we present a quantitative interpretation of induced polarization signatures from brine-filled rock formations with conductive inclusions and show that new opportunities in geophysical exploration and characterization could arise. Initially tested with model systems with solid conductive inclusions, this theory is then extended and experimentally tested with nanoporous conductors that are shown to have a distinctive spectral IP response. Several of the tests were conducted with nano-porous sulfides (pyrite) produced by sulfate-reducing bacteria grown in the lab in the presence of a hydrocarbon source, as well as with field samples from sapropel formations. Our discoveries and fundamental understanding of the electrode polarization mechanism with solid and porous conductive inclusions suggest a rigorous new approach in geophysical exploration for mineral deposits. Moreover, we show how induced polarization of biologically generated mineral deposits can yield a new paradigm for basin scale hydrocarbon exploration.
在过去几十年中，激发极化（induced polarization，简称 IP）测绘受到了越来越多的关注，因为电激发极化已被证明可以为探测地质材料（如粘土、矿石、黄铁矿以及潜在的碳氢化合物）的存在提供有趣的特征。然而，将与 IP 相关的复杂电导率与相应材料的固有物理性质联系起来的努力在很大程度上仍然是经验性的。在这里，我们提出了一种定量解释充盐水岩地层中含有导电夹杂物的激发极化特征的方法，并表明在地球物理勘探和描述中可能会出现新的机会。该理论最初是用具有固体导电夹杂物的模型系统进行测试的，然后进行了扩展并通过纳米多孔导体进行了实验测试，这些导体具有独特的光谱 IP 响应。其中一些测试是在实验室中使用硫酸盐还原菌在碳氢化合物源存在的情况下生成的纳米多孔硫化物（黄铁矿）以及萨布罗佩尔地层的野外样本进行的。我们对固体和多孔导电夹杂物的电极极化机制的发现和基本理解，为矿产资源的地球物理勘探提供了一种严格的新方法。此外，我们展示了如何通过生物生成的矿物沉积物的激发极化来为盆地规模的碳氢化合物勘探提供一个新的范例。
