Mechanistic Studies of Improved Foam EOR Processes

Rossen, William R.

University of Texas at Austin

关键词: Sweep Efficiency;    02 Petroleum;    Trapping;    Polymers;    Pressure Gradients;   

DOI  :  10.2172/823157
RP-ID  :  NONE
RP-ID  :  FC26-01BC15318
RP-ID  :  823157

美国|英语

来源: UNT Digital Library

【 摘 要 】

The objective of this research is to widen the application of foam to enhanced oil recovery (EOR) by investigating fundamental mechanisms of foams in porous media. This research will lay the groundwork for more applied research on foams for improved sweep efficiency in miscible gas, steam and surfactant-based EOR. Task 1 investigates the pore-scale interactions between foam bubbles and polymer molecules. Task 2 examines the mechanisms of gas trapping, and interaction between gas trapping and foam effectiveness. Task 3 investigates mechanisms of foam generation in porous media. The most significant progress during this period was made on Tasks 1 and 3. Research on Task 1 focused on selecting and characterizing a surfactant/polymer formulation for initial experiments. The two (high-quality and low-quality) strong-foam regimes were identified from steady-state coreflood data for the formulation without polymer, for comparison with behavior with polymer. This formulation showed unconventional behavior in the low-quality regime in that pressure gradient decreases at increasing liquid injection rate. Such behavior was not seen in most previous studies of foam, but it is consistent with dense-CO{sub 2} foam data recently obtained in our laboratory. We are considering the significance of the unconventional trend in the data and proceeding with initial experiments with polymer. Research on Task 3 focused on foam generation at limited pressure gradient in sandpacks. In these experiments liquid injection rate and pressure drop across the core are held fixed, and gas injection rate responds to creation and properties of foam. Initial experiments included three permeabilities (1.2, 3.6 and 5 darcy), three surfactant concentrations (0.12, 1.2 and 2.4 wt%) and two liquid injection rates (1.29 and 2.76 ft/day). Separating experimental artifacts from physical phenomena in these experiments is difficult and an ongoing process.