PH sensitive polymers for novel conformance control and polymer flooding applications

摘要: Polymer flooding is a commercially proven technology to enhance oil recovery from mature reservoirs. The main mechanism for improving increase the viscosity of injection water by adding polymer, thereby creating favorable mobility ratio improved volumetric sweep efficiency. However, polymer brings on several potential problems: a) high pressure with associated pumping cost; b) creation unwanted well fractures; and c) mechanical degradation polymers due shear near wellbore. solutions permeability reduction retention reduce mobility, simultaneously drop required propagation bank. objective this dissertation develop an process that can minimize impact those problems in process, extend application conformance control. This accomplished utilizing pH sensitivity partially hydrolyzed polyacrylamide (HPAM), which most commonly used EOR polymer. idea “low-pH process” inject HPAM solution at low-pH conditions into reservoir. low condition, enables pass through wellbore region relatively drop. save considerable amount pump horse power during injection, also use large-molecular-weight without danger while injecting below fracture gradient. Away region, becomes thickened pH, occurs naturally spontaneous reaction between acid rock minerals. lowers brine increases displacement efficiency, as intended. Another control highly heterogeneous As secondary method, high-permeability zones, but not low-permeability zones. under be placed deep such sands preferentially, because its viscosity. It then viscosified increase, caused geochemical reactions minerals With sands, subsequently injected diverted zone, so bypassed trapped zone efficiently recovered. To evaluate extensive laboratory experiments were systematically conducted. first step, rheological properties solutions, steady-shear viscoelastic behavior, measured functions pH. effects various variables, concentrations, salinity, molecular weight, degree…