Improvement in thermo‐chemical stability of nanocomposite preformed particle gels for conformance control in harsh oil reservoir conditions

Abstract

Gel treatment is one of the most promising technologies to improve conformance control in heterogeneous reservoirs. In this paper, new enhanced preformed particle gels (PPGs) are introduced for conformance control in high‐temperature and high‐salinity oil reservoirs. The thermo‐chemical stability of this product is due to the incorporation of a new monomer, N,N‐dimethyl acrylamide (DA), to the structure of the last well‐known nano‐composite PPGs. Four species, N,N‐dimethyl acrylamide, 2‐acrylamido‐2‐methylpropane sulphonic sodium salt (AMPSNa), acrylamide (AM), and N‐vinylpyrrolidone (NVP) monomers, were used to synthesize these PPGs via free radical cross‐linking polymerization at room temperature using N,N‐methylenebis (acrylamide) as a cross‐linker. The mechanical properties of these new classes of PPGs were enhanced by adding the nano‐clay montmorillonite Na+. A temperature stability agent was also used to make these special PPGs compatible with high temperature and salinity reservoir conditions. A systematic study on PPGs preparation was conducted to improve PPGs stability for harsh reservoir conditions that exist in Persian Gulf oil reservoirs (a temperature of 145 °C and a water total dissolved solid of 225 000 mg/L). PPGs prepared with 0.30 g/g (30 wt%) of a 2:1:1:2 molar mass ratio of AM, DA, NVP, and AMPSNa could be completely stable for the mentioned conditions. Rheological behaviours of these PPGs were investigated and a mathematical model for prediction of storage modulus up to onset of elastic to viscous phase was presented. The results of this study reveal useful insights about the selection of appropriate material for successful conformance control in the heterogeneous reservoirs.

Self-adaptive preferential flow control using displacing fluid with dispersed polymers in heterogeneous porous media

“…The Maxwell constitutive relation is correctly introduced into the momentum equation to account for the viscoelastic behaviour of polymers (Saghafi et al 2016). The viscoelastic body force F el of a Maxwell fluid is derived as…”

“…The Maxwell constitutive relation is correctly introduced into the momentum equation to account for the viscoelastic behaviour of polymers (Saghafi et al. 2016). The viscoelastic body force of a Maxwell fluid is derived as where is the Cauchy stress tensor, the polymer intrinsic dynamic viscosity, E the elastic modulus and the viscoelastic relaxation time.…”

“…(2) incorporation of complex viscoelastic non-Newtonian behaviour for the polymer solution is a necessity (Wang et al 2000;Abdulbaki et al 2014;Saghafi et al 2016); and (3) such an intricate flow system should be modelled in the complex solid porous geometries of rocks. In our previous work (Xie, Lv & Wang 2018b), we reduced the problem to a two-phase flow system by treating the polymer in water as a well-mixed continuous phase with a viscoplastic behaviour according to their bulk rheological properties (Wever et al 2011;Cohen-Addad, Höhler & Pitois 2013;Jung et al 2013).…”

“…2014; Saghafi et al. 2016); and (3) such an intricate flow system should be modelled in the complex solid porous geometries of rocks. In our previous work (Xie, Lv & Wang 2018 b ), we reduced the problem to a two-phase flow system by treating the polymer in water as a well-mixed continuous phase with a viscoplastic behaviour according to their bulk rheological properties (Wever et al.…”

Dual-Responsive Nanotubes Assembled by Amphiphilic Dendrimers: Controlled Release and Crosslinking

“…The traditional method in profile control is that the mixing fluid, composed of polyacrylamide and a crosslinking agent, is injected without "precise" control of the gelation time, causing a blockage near the bottom of the well and reducing the water flooding efficiency. The ideal gelation time should be able to be regulated over a wide range and selected according to the real oil field conditions, for which problems still remain due to unpredictable gelation positions [8]. Stimuli-responsive nanocapsules are proposed as a potential candidate system to realize precise deep control and improve the efficiency of oil production through controlling the releasing rate of the crosslinking agent and correspondingly regulating the gelation time and position [9].…”