Research on Optimal Blocking Limits and Injection Parameter Optimization of Polymer Microsphere Conformance Control

Abstract

Polymer microsphere (PM) profile control has been attributed to improving sweep efficiency during the oil development process. The critical factors for PM conformance control are the plugging properties controlled by matching the relationship between the throat diameter and particle size and the injection parameters. A new matching relationship between the reservoir and PM based on the function of blocking rate and the ratio of throat diameter to microsphere diameter (C R) is established to choose the most appropriate PM size. The blocking rate indicates that it will get the most excellent plugging effect when C R is 0.5. The displacement experiments under different injection concentrations and other injection volumes show that the blocking rate is increased by injection concentration and finally stabilized. A similar trend is presented between the injection volume and plugging rate. The optimal injection concentration is 0.5%, and the optimal injection volume is 0.3 PV. According to the new size selection method and injection parameter optimal method, PM100 chooses to conduct field application. PM100 presents a good performance with a success rate of 37.5% and a validity period of more than 120 days, and its daily oil production rate increased 1.7 times, on average, and finally, the total oil increase is 556 t. The optimal size microsphere shows a good EOR effect, which indicates that this size selection method is reasonable.

Study on the Profile Control and Oil Displacement Mechanism of a Polymer Nano-microsphere for Oilfield

“…Reservoirs with low permeability in China have complex pore structures. − There are some problems such as severe water channeling and low oil recoveries during the water injection development. − Technologies of conventional plugging and profile control cannot meet the production demands of oilfields. − Polymer microspheres have attracted increasing attention in the area of depth profile control in recent years. − Polymer nano-microspheres have many advantages such as the small particle diameter, good elasticity, and deformation ability, making the microspheres easily reach the deep formation and selectively block the dominant channels of water flooding. − The permeability of the profound formation is changed, and the swept volume of the displacement fluid is enlarged due to the “migration-plugging-remigration-replunging” of microspheres. − …”

Highly Stable Polymer-Enhanced Pickering Foams for Hydraulic Fracturing Applications

“…Alkyl polyglycoside (APG) was chosen as the surfactant because of its biodegradability and excellent performance under high-temperature conditions. , As a green polymer, xanthan gum was used as a thickener due to its high viscosity and high temperature resistance . As previously discussed, a major concern regarding the injection of polymer solutions into reservoirs is the potential for small pores and throats to be clogged by polymers that have been adsorbed. , As the polymer concentration is always less than 0.5% after the addition of CNCs, pore-throat obstruction in shale caused by polymer expansion may not be a significant concern. In addition, molecular dynamics (MD) simulations were conducted to reveal the complex interactions between three stabilizers (surfactant, polymer, and nanoparticle) and the water phase on a molecular scale in order to better understand the underlying mechanisms of various stabilizers in thin films.…”