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

Abstract

Summary 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 -permeability-impairment 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.