Benefits of the induced polarization geoelectric method to hydrocarbon exploration

Abstract

Delineation of hydrocarbon prospective areas is an important issue in petroleum exploration. The geoelectric method helps to identify attractive areas and reduces the overall drilling risk. For this purpose, induced polarization (IP) effects are mapped caused by the presence of epigenetic pyrite microcrystals in sedimentary rocks. These crystals occur in a shallow halo-shaped mineralogical alteration zone, often overlying a deeper-seated hydrocarbon accumulation. Local enrichment in pyrite results from reducing geochemical conditions below an impermeable layer. The imperfect top seal of the accumulation permits minor amounts of hydrocarbons to escape and migrate through the overlying rocks to shallower levels. During migration, hydro-carbons encounter an impermeable barrier, forming an altera-tion zone. Induced polarization logging and coring in wells confirm this working model. Geoelectric surveying visual-izes anomalies in electric potential difference measured be-tween receiver electrodes. The differentially normalized method (DNME) inverts the registered decay in potential differences, establishing a depth model constrained by seismic and petro-physical data. Diagnostic geoelectric attributes are proposed, giving a better grip on chargeability and resistivity distribution. Acquisition and processing parameters are adjusted to the target depth. Encouraging results are obtained in deeper [Formula: see text] as well as in very shallow water. Onshore, a grounded current transmitter is used. Geoelectric surveys cover different geologic settings with varying target depths. The success ratio for predicting hydrocarbon occurrences is high. So far, 40 successful wells have been drilled in Russia on mapped geoelectric anomalies. Out of 126 wells, the method produced satisfactory results in all but two cases. The technique reduces the risk attached to new hydrocarbon prospects and allows better ranking at a reasonable cost.

Induced polarization response of porous media with metallic particles — Part 3: A new approach to time-domain induced polarization tomography

“…In performing acquisition this way, there is a strong reduction in the time required to perform a survey. This may be crucial for some specific applications, such as marine time-domain induced polarization data (Veeken et al, 2009) to detect ore bodies or to identify unexploded ordinance (UXO) at sea using a network of electrodes dragged by a boat.…”

Upscaling of spectral induced polarization response using random tube networks

“…Veeken et al 2009), location and delineation of contaminant plumes (e.g. Mewafy et al 2013;Johansson et al 2015;Ntarlagiannis et al 2016), monitoring of biodegradation processes in contaminated area (e.g.…”

Study on the induced polarization model in the exploration for shale gas in southern China

“…One considered that the reservoir itself was a dynamic multiphase balance system, in which the double electric layer formed from bi-phase medium, and was the source in which the IP field was come from (He, 2007). Another was called 'the micro-seepage model' which considered IP effect happened above the reservoir because the hydrocarbons migrated to the upper reducing zone, and resulted in the formation of rich pyrite which was the strong source of IP effect (Veeken, 2009). …”