Selectivity of Pore-Scale Elastic Microspheres as a Novel Profile Control and Oil Displacement Agent

Abstract

Pore-scale elastic microspheres were prepared controllably and their swelling property, stability, and creeprecovery property in brine water were analyzed in laboratory. The goal of the research was to study the selectivity of the porescale elastic microspheres as a novel profile control (water injection profile modification) and oil displacement agent. The matching factor between particle size of elastic microspheres and pore throat diameter of sand pack model was introduced to characterize their matching relationship. The results indicate that the optimal matching factor is 1.35−1.55. Besides, the profile control and oil displacement effect were studied using a series of heterogeneous double-tube sand pack models with optimal matching factors. The shunt flow experiments show that when the matching factor is an optimal value, the elastic microspheres prefer to plug the high-permeability layer selectivity and almost do not clog the low-permeability layer. The oil displacement experiments show that the elastic microspheres have the characteristic of plugging water without plugging oil and can improve the sweep status and oil displacement effect of low-permeability layer and low-permeability area in the high-permeability layer. According to the experimental results and actual situation of Block Liu 28-1, an optimal program for the profile control and oil displacement of elastic microspheres was proposed and conducted. The results show that the elastic microspheres can improve the water injection profile effectively. The results also confirm that the matching factor is an appropriate measure to evaluate the profile control and oil displacement effect of elastic microspheres and to guide the field test.

Preparation and performance of fluorescent polyacrylamide microspheres as a profile control and tracer agent

“…The differential pressure fluctuates within a wide range at the second-stage (II), and this phenomenon was defined as ''wave-type variation'' (Yao et al 2012). In the subsequent injection of brine, the pressure remains in this kind of variation in the range of 35-60 PV and then reaches a relatively high and constant level.…”

“…Polyacrylamide microspheres have been successfully applied to reduce water production and enhance oil recovery in mature reservoirs with well-developed fractures or ultra-high permeability streaks/channels (Yao et al 2012(Yao et al , 2013Hua et al 2013;Li et al 2014). However, it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that was used to enhance oil recovery and was already present in production fluids.…”

Study on a Novel Gelled Foam for Conformance Control in High Temperature and High Salinity Reservoirs

“…This high water cut in production wells has become a common problem in high temperature and high salinity oilfield developments [6][7][8]. Conformance control is widely used and has been proven to be an important measure to improve the efficiency of water flooding and enhance the oil recovery [9][10][11][12][13][14]. However, the lack of a suitable conformance control agent restricts the popularization and application of conformance control treatment in high temperature and high salinity reservoirs.…”

Application of Depth Regulating and Displacing Technology of Nano-micron Hydrogel Microspheres in Oilfield

“…When the micron scale microspheres enter into the formation, they will produce crosslinking between the particles under formation temperature and water immersion, and then plug big holes. While the nanoscale microspheres into the formation will expand to adjust the formation of deep profile and can improve water flooding effect [9][10]. According to the actual circumstance of injection formation, choosing the diameter of injection microspheres and injection method is necessary to use gel microspheres in oilfield injection.…”