Control of flow through porous media using polymer gels

Abstract

We examine the effect of a dynamic stress on the reduction of flow in porous media using polymer gels formed in situ. To develop the theory for the response of the gel, we consider three dominant factors: (a) compressive (elastic) deformation of the gel and porous medium, (b) microscopic flow in this system, and (c) gel displacement. The latter occurs when the stress p is larger than a certain critical value pc, satisfying pcR2=constant (R=effective pore radius), where the constant is an increasing function of elastic modulus of the gel and its cross-linking energy. The expulsion of the gel above pc is reminiscent of growing Saffman-Taylor instabilities. To derive analytic expressions for the macroscopic saturation profiles we use the formalism for fully miscible two-phase flow. The equation of evolution of the pressure, established by mass balance arguments, was solved analytically. For p<pc, the pressure obeys an exponential saturation function while for p<pc, it first increases, reaches a maximum value, and then decreases towards an asymptotic value. These theoretical predictions are supported by our experiments consisting of injecting (salt) water at a constant flow rate in porous samples containing a organically cross-linked polymer gel (co-polymer of acrylamide and t-butyl-acrylate cross-linked using poly-ethylene-imine). The data confirms further that the product pcR2 is constant and prove that both pc and the maximum pressures increase with intrinsic gel strength.

Gelation Kinetics and Performance Evaluation of an Organically Crosslinked Gel at High Temperature and Pressure

“…For example, copolymers of polyacrylamide tert-butyl acrylate (PAtBA) (Morgan et al 1998), mixtures of acrylamide and acrylamido-2-methylpropane sulfonic acid (AMPSA) (Vasquez et al 2003), mixtures of acrylamide, AMPSA and N,N-dimethyl acrylamide (Vasquez et al 2005) can be crosslinked with PEI through covalent bonding. These PEI crosslinked systems have been extensively examined in porous media (Hardy et al 1998;Alqam et al 2001;Zitha et al 2002;Vasquez et al 2003Vasquez et al , 2005.…”

Study of the Potential of Amino Resin to Control Excessive Water Production in the Indian Oilfields

“…The conventional water control techniques, such as squeeze cementing and mechanical isolation with bridge or cement plugs, have not been very successful in reducing the water production for a long period of time. Polymer gel systems have emerged as one of the most effective tools for controlling water production (MoradiAraghi, 2000;Vossoughi, 2000;Grattoni et al, 2001;Zitha et al, 2002;Nijenhuis, 2003;Reddy et al, 2005;Alhajeri et al, 2006;Al-Muntasheri et al, 2007). In this technique a suitable polymer system is pumped into the formation around the wellbore and then it propagate through the rock Active content 63 (%) (Oven dried method for 3 h at 105 • C) 6.…”

Investigation of a Novel Chemical for Bullhead Water Shutoff Treatments

“…[1][2][3] The most widely used water control techniques rely on hydrophilic polymers 4 and crosslinked polymer gels. [5][6][7][8] Water treatments with these chemicals are often accomplished when oil-bearing zones can be mechanically or otherwise physically isolated. 9 Bullhead treatments, i.e.…”