Patent RU-2757386-C1 (RU)
Title: Method for conducting electromagnetic monitoring of hydraulic fracturing
Inventor: Salishchev Mikhail Vsevolodovich
IPC: G01V99/00
Filed: 2020-11-16
Granted: 2021-10-14
Abstract: FIELD: oil and gas industry.  
     SUBSTANCE: invention relates to the oil and gas field, hydraulic fracturing operations, in particular to methods for conducting electromagnetic monitoring of hydraulic fracturing. The proposed method for conducting electromagnetic monitoring of hydraulic fracturing includes: obtaining a background layered geoelectric section based on geophysical studies of wells; building a model of the forecast distribution of proppant based on the modeling of hydraulic fracturing taking into account natural fracturing and forecast cracks; building maps of the specific electrical resistances of the forecast distribution of proppant; determination of the parameters of electromagnetic monitoring based on the modeling of electromagnetic fields using a map of the specific electrical resistances of the predicted proppant distribution and the background layered geoelectric section. At the same time, the parameters are determined according to the criterion of the maximum electromagnetic response and include at least: the value of the dipole moment (conductor length, current strength) of the electromagnetic field source, its position relative to the fracturing zone, taking into account the electrical conductivity of the rock and the distance to the target interval of the fracturing (the volume of the fracturing rocks), a narrow frequency range of the generator from a wide range of 0.01-10 Hz, the location of observation points (step, profile length), removal of the control receiver, based on the modeling of electromagnetic fields using a map of the specific electrical resistances of the predicted proppant distribution and the background layered geoelectric section according to the criterion of the maximum electromagnetic response; conducting electromagnetic monitoring based on certain parameters, including: the location of observation points on the earth’s surface with the installation of a control sensor, the location of the electromagnetic field source in the well, the excitation of the electromagnetic field in the source, registration of the components of the electromagnetic field (Е х , Е у , Н х , Н у  and H z ); construction of an a priori geological and geophysical model based on the monitoring carried out; conducting hydraulic fracturing with the injection of an electrically conductive proppant; repeated electromagnetic monitoring based on certain parameters, including: excitation of the electromagnetic field in the source, registration of the components of the electromagnetic field (Е х , Е у , Н х , Н у  and H z ); construction of a posteriori geological and geophysical model of the environment based on the monitoring carried out after the hydraulic fracturing; construction of a model of the proppant position based on a difference model of the medium, reflecting the change in the electrical conductivity of the medium as a result of hydraulic fracturing and the appearance of an electrically conductive proppant.  
     EFFECT: providing the possibility of the more accurate determination of the proppant in hydraulic fracturing cracks, as well as improving the method for conducting electromagnetic monitoring by selecting the position of the electromagnetic field source at which the maximum electromagnetic response from the proppant occurs.  
     20 cl, 16 dwg