Our experience with the induced polarization (IP) and resistivity method for hydrocarbon exploration has shown both successful surveys and limitations of the method. Four examples demonstrate a close correlation between shallow IP and resistivity anomalies and deeper hydrocarbon production. In each of these examples, anomalies occurred over the producing fields which have significantly greater amplitudes than the variations in the surrounding background response.Another important result of our research is the development of a geological/geochemical model for the formation of IP and resistivity anomalies over hydrocarbon reservoirs. The two main requirements for formation of IP and resistivity anomalies, according to this model, are: (1) absence of any thick imper-meable seals, such as evaporites, above the reservoir and (2) presence of porous, iron-rich, near-surface host rocks, such as clastic rock sequences. The IP and resistivity method can be more successfully applied by selecting those areas for surveys in which these two requirements hold.We have also found that the IP/resistivity method for hydrocarbon exploration has significant limitations. Many areas do not appear to have the required geological and geochemical conditions for the formation of IP or resistivity anomalies. IP and resistivity anomalies may also need to be tested with shallow drill holes to separate anomalies caused by hydrocarbon seepage from false anomalies due to other causes.

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