Mechanism experimental study on flooding control of Soft Microgel by low-field nuclear magnetic resonance

Abstract

The research method of LF-NMR(low field nuclear magnetic resonance) combined with core displacement device has become important experiment was used to study the Water Flooding SCT(swept control technology by water flooding) of soft microgel. Besides, the transverse relaxation time spectrum and the “visual” evaluation method based on LF-NMR were used to investigate the microscopic mechanism of expended sweep volume of soft microgel in single core experiment. The displacement conformance effect of flexible microgel in parallel double-core and its displacement mechanism at different pore scales were analyzed by transverse relaxation time spectrum. The results of single core experiments show that the soft microgel can expand the sweep volume, mainly in the relatively large pore throat, with 15.43%. The results of parallel double-core experiments indicate that after SMG flooding, the recovery of low permeability core increased by 29.5%, high permeability core increased by 15.3%, comprehensive recovery increased by 22.0%, and the ratio of low permeability recovery increased by nearly 2 times that of high permeability core. The soft microgel flooding technology can effectively activate the remaining oil in different pore sizes of the core, among which the medium pore (12.1%) is more used than the large pore (5.6%) and the small pore (4.2%).