HR: 1340h
AN: H23A-1415    [Abstracts]
TI: Mobility Controlled Flooding (MCF) Technology for Enhanced Sweeping and NAPL Remediation in Heterogeneous Systems
AU: * Zhong, L
EM: lirong.zhong@pnl.gov
AF: Pacific Northwest National Lab, Battelle Boulevard, MSIN: K6-96 , Richland, WA 99354 United States
AU: Oostrom, M
EM: mart.oostrom@pnl.gov
AF: Pacific Northwest National Lab, Battelle Boulevard, MSIN: K6-96 , Richland, WA 99354 United States
AU: Wietsma, T
EM: wietsma@pnl.gov
AF: Pacific Northwest National Lab, Battelle Boulevard, MSIN: K6-96 , Richland, WA 99354 United States
AB: Heterogeneity is often encountered in subsurface contamination characterization and remediation. Low-permeability zones are bypassed when remedial fluid is injected into heterogeneous systems. The contaminant in the bypassed areas is therefore untouched by the remedial fluid, which can prolong the remediation operations significantly. Methods of forcing fluids into low-permeability flow paths have been developed and widely implemented to solve the heterogeneity-induced bypassing problem encountered during oil recovery in the petroleum industry over the past 40 years. Since the intent of the petroleum reservoir engineers is to control the mobility of the injected fluid in the high-permeable zones so that the fluid can be pushed through the low-permeable zones to contact and mobilize the remaining oil in these zones, this method are referred as mobility controlled flooding (MCF) technology in the petroleum engineering literature. Two methods of mobility control have been developed. One method is to use a water-soluble polymer to increase the viscosity of the injectate so that the in situ pore pressure is raised, and cross-flow between layers with different permeability occurs. The other method is to use surfactant-foam flood to generate foam in high permeable zones in situ; therefore, the injected fluid is forced into the low-permeable areas. A water-soluble polymer, xanthan gum, and surfactant MA-80 was used to formulate MCF remedial fluids to remediate nonaqueous phase liquid (NAPL) contaminated heterogonous systems in two-dimensional (2-D) flow-cell (40 by 50 by 5 cm) experiments. It was demonstrated that the MCF technology is capable of sweeping the low-permeability flow paths. The bypassing of low-permeable zones was significantly reduced. The removal of NAPL trapped in the low-perm zones was remarkable enhanced attributed to more efficient NAPL mobilization. The results also indicate that the MCF technology is able to manage the fluid density effects. The unfavorable irregular displacing front observed during the plain surfactant solution remediation flood due to the density difference between the resident and remedial fluids disappeared when the MCF surfactant-polymer solution was used.
DE: 1800 HYDROLOGY
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: Fall Meeting 2005