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The main objective of the laboratory and field studies was to develop an efficient and flexible reservoir conformance control (RCC) technology through improvement of the standard silicate method with joint application of "liquid” polymer and nanoparticle (silica) suspension. Similarly, the important idea was to simplify the surface facilities and reduce cost of chemicals, treatment time, and human force. The laboratory studies focused on laser particle sizing, dissolution kinetics, colloid chemical, rheological, gelation kinetics and setting time, and flow properties of polymer and nanosilica containing silicate gel methods in porous media (sandstone). Based on the experimental findings, it was found that “liquid” polymers and “liquid” nanosilica readily and rapidly dissolve and mix in water, and the solutions are free of microgels and the mechanical entrapment was minimal even in low permeable sandstone cores. In addition, they decreased significantly the surface tension and interfacial tension. It was proved that such “liquid” additives provide unprecedented flexibility to the technology and the enhanced methods may be attained with labor and expenditure effective way. The main effect of polymer was to stabilize the silicate gel against syneresis (spontaneous fracturing) and formed a secondary network in gel and that fact provided more thermal stability of gel. The nanosilica beneficially influenced the gelation kinetics of polymer containing silicate solutions. The main effect could be traced back to advanced nucleation of gel formation. Additional positive effect of nanoparticles is that its presence in the reaction mixture makes more flexible the pH control in both the bulk phase and in porous media. The extra beneficial properties of “liquid” polymers and nanomaterials in all oilfield chemical applications may significantly contribute to improvement of standard technologies; meanwhile the surface facilities can be simplified, or completely eliminated (e.g. the “liquid” polymer and nanosilica can be directly injected to basics sodium silicate solution at wellhead). Earlier, the “liquid” polymer was successfully applied in water shutoff in Oman. Recently, a new field programs is running in Hungary using silicate/polymer solution with nanoparticle (silica) fillers. The paper details the “from laboratory to field” activities, and demonstrates the superiority of the novel concept. The successful field pilots, the join application “liquid” polymers, and nanosilica may open new vistas in reservoir conformance control. |
