Inter-well electromagnetic detection system and method

Abstract

The invention discloses an inter-well electromagnetic detection system and method, and belongs to the technical field of resource drilling. The method comprises the following steps: constructing a transmitting galvanic couple source by using a metal sleeve of a cased well in a plurality of wells; applying excitation signals to the transmitting galvanic dipole source to enable the transmitting galvanic dipole to transmit transmitting signals, then receiving the transmitting signals transmitted by the transmitting galvanic dipole source through the receiving electrodes distributed on the measuring lines, finally, detecting the response characteristics of the received transmitting signals, and obtaining resistivity distribution of the cross-well oil and gas reservoir. According to the method,magnetic dipole detection adopted in a conventional cross-well electromagnetic method is changed into electric dipole detection, the transmitting power of transmitting signals can be improved, and therefore the detection range is enlarged. The shielding effect of the sleeve on electromagnetic signals in a conventional cross-well electromagnetic method can be eliminated, the characteristic that the metal sleeve has good electrical conductivity is further utilized, emission current is directly applied to the metal sleeve to serve as a long dipole emission line source, and cross-well long-distance detection can be achieved.

Description

technical field [0001] The invention belongs to the technical field of resource drilling, and in particular relates to an interwell electromagnetic detection system and method. Background technique [0002] The cross-well detection technology has gradually developed and formed two detection methods with different physical mechanisms: cross-well seismic and cross-well electromagnetic. As an important detection method at present, the interwell electromagnetic method can be used to detect the distribution of remaining oil and find oil and gas enriched areas, so as to improve the drilling success rate and recovery rate. Compared with the cross-well seismic method, the cross-well electromagnetic method is more sensitive to the changes in the interwell formation characteristics and fluid properties, and can directly provide the interwell reservoir resistivity distribution information, and then realize the description of the fluid spatial distribution according to the resistivity d...

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Problems solved by technology

Taking oil and gas production wells as an example, the actual wellbore size is very narrow, which limits the diameter of the magnetic couple source in the well, thereby limiti...

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