Experimental Investigation and Correlation of Treatment in Weak and High-Permeability Formations by Use of Gel Particles

Abstract

Near-wellbore formation treatment by injection of suspensions of deformable gel particles is explored as a method of prevention of lost circulation of drilling fluids, handling of reservoir permeability heterogeneity, and controlling water production in mature waterflooded oil fields containing highly permeable and weak zones. Conditioning and plugging of such formations and the resulting permeability impairment occurring during injection of suspensions of deformable gel particles are investigated experimentally. The effect of concentration, flow rate, and gel-particle sizes of suspensions on the prevailing pore-plugging processes is inferred by flow tests conducted with 3,800-md 16-to 20-mesh sandpacks. Prevailing particle-entrapment and -permeabilityimpairment mechanisms are identified under various conditions by means of specially formulated diagnostic equations. Appropriate dimensionless groups are used to develop several empirical correlations of the experimental data, which can assist in choosing suitable gel-particle suspensions and proper application conditions required for effective near-wellbore-formation treatment. This reveals valuable insights and information about the functional trends of sandpack plugging by gel-particle suspensions, which can help in successful design and mitigation of formation-plugging treatments in the field.

Migration characteristics and deep profile control mechanism of polymer microspheres in porous media

“…To better exploit the potential of residual oil in low-permeable layers, researchers have developed various deep profile control techniques, such as colloidal dispersion gels (CDGs), preformed particle gels (PPGs), polymer microspheres, and inorganic gel coatings. [14][15][16][17][18][19] CDGs are a gel system that relies on intramolecular crosslinking between a polymer and crosslinking agent. 20 With the delayed crosslinking technique, CDGs can selectively enter high-permeability layers and thus effectively ease interlayer cross-flow.…”

“…2,25,26 However, due to the large particle sizes and irregular shapes, PPGs can block reservoirs and are ineffective in depth profile control. 19,27 Thus, PPGs are often used to block high-permeable layers and fissures. Compared with organic profile control agents, inorganic gel coatings possess a higher heat resistance, salt resistance, and sealing performance, but the viscosity of injection liquids containing inorganic gel coatings is similar to that of water, which easily pollutes low-permeability oil zones of reservoirs.…”

“…3 Moreover, abundant injection water and formation water are ineffectively produced, which increases energy consumption during production, pipeline corrosion, and sewage treatment costs and causes environmental pollution. [14][15][16][17][18][19] CDGs are a gel system that relies on intramolecular crosslinking between a polymer and crosslinking agent. [6][7][8][9][10][11][12][13] However, as the reservoir structure becomes increasingly complex after entering the high-or ultrahigh-water-cut stage, the existing general profile control technology hardly meets the actual needs of reservoirs.…”

“…20 With the delayed crosslinking technique, CDGs can selectively enter high-permeability layers and thus effectively ease interlayer cross-flow. 19,27 Thus, PPGs are often used to block high-permeable layers and fissures. Additionally, the sensitivity to high temperature and high salinity limits the application of CDGs in oil reservoirs under harsh conditions.…”

Study of the mechanisms of streamline-adjustment-assisted heterogeneous combination flooding for enhanced oil recovery for post-polymer-flooded reservoirs

“…Moreover, the remaining oil is much dispersed and is difficult to exploit (Hou 2007;Muhammed et al 2012;Urbissinova et al 2010;Zhang et al 2014;Zhou et al 2013). Therefore, researchers and engineers have developed many post-polymer-flooding EOR methods (Al-Ibadi and Civan 2013;Choi et al 2010;Han et al 2014;Lin et al 2003;Pirayesh et al 2014;Ranganathan et al 1998;Sang et al 2014;You et al 2011;Wang et al 2003;Wever et al 2013), including alkali-surfactant-polymer (ASP) flooding, weak gel flooding and colloidal dispersion gel or bulk gel flooding. These EOR methods have been successfully implemented, but further applications are limited due to the complex geological properties and high risk of destructive blockage.…”