Application of magnetic nanoparticles mixed with propping agents in enhancing near-wellbore fracture detection

The results of laboratory experiments showed that the relative enhancement of the volume susceptibility of the fractured zones depend on factors such as the type of proppants (e.g., magnetic versus non-magnetic proppants), the concentration of nanoparticles in the injected solution, and the volume of nanoparticle solution and proppants. The use of magnetic nanoparticles lead to a significant enhancement in the detection of fractures, even with widths as small as 0.3 cm. The numerical simulations on synthetic examples show that the nanoparticle concentration in hydraulic fractures is significantly higher than that in the surrounding porous rock in the case of tight formations. We have then illustrated from the experimental and numerical methods that the superparamagnetic nanoparticles, which are mainly concentrated in the fractures can be used as contrast agents mixed with the proppants to highlight the fractures and detect the location of proppants. This detection technique can be applied in the field by using the borehole magnetic susceptibility tools for pre-fracturing and post-fracturing measurements in open-hole wells.