The first large-scale colloidal dispersion gel (CDG) pilot test was conducted in the largest oil field in China, Daqing oil field. The project was initiated in May 1999, and injection of chemical slugs was completed in May 2003.This paper provides detailed descriptions of the gel-system characterization, chemical-slug optimization, project execution, performance analysis, injection facility design, and economics. The improvements of permeability variation and sweep efficiency were demonstrated by lower water cut, higher oil rate, improved injection profiles, and the increase of the total dissolved solids (TDS) in production wells.The ultimate incremental oil recovery (defined as the amount of oil recovered above the projected waterflood recovery at 98% water cut) in the pilot area would be approximately 15% of the original oil in place (OOIP). The economic analysis showed that the chemical costs were approximately U.S. $2.72 per barrel of incremental oil recovered. Results are presented in 15 tables and 8 figures.* Reservoir quality: Daqing classifies reservoir quality into three types; Type I reservoirs have the best quality, with good continuity, thick sand layers (>3 m), and higher permeabilities (>300 md); Type II reservoirs have poorer quality, with less continuity, thinner sands (1 to 3 m), and lower permeabilities (>100 md); and Type III reservoirs have the worst quality, with discontinuous sand layers, thin pay (<1 m), and low permeabilities (>10 md).
Recent experimental observations of the phase behavior of methane-n-paraffin hydrocarbon binary systems are used to make a phase rule analysis of such systems. The vapor-liquid equilibria of light hydrocarbon systems are complicated by liquid-liquid immiscibility and solids formation at low temperatures.The system studied here has limited liquid phase miscibility with a quadruple point involving o gas phase, two liquid phases, and a solid phase.Experimental techniques were developed to sample and analyze gas phases containing concentrations of n-heptane in the range of 0.00001 mole fraction with good precision. Binary K values for methane and n-heptane are reported at intervals of 20°F. from 0" to -100°F. for pressures up to the criticals for the mixtures. The results are reported numerically and illustrated graphically. Additional phase observations were made below the critical temperature of methane to confirm and extend the phase behavior of the methane-n-heptane system as reported by Kohn.Since the review of the vapor-liquid equilibria of light hydrocarbons at low temperatures by Price and Kobayashi ( 1 2 ) , studies on the phase behavior of the methane-nhexane ( 4 ) , methane-n-heptane ( 5 ) , and methane-noctane (6) systems by Kohn and co-workers have appeared. The methane-n-decane systems were reported by Stalkup et al. ( 1 7 ) and also studied by Koonce and Kobayashi ( 7 ) . Koonce et al. (8) reported vapor-liquid equilibria data on the ternary methane-propane-n-decane and the methanepropane-n-heptane systems in 1965. GENERAL DISCUSSION OF PHASE BEHAVIOR IN METHANE-n-PARAFFIN HYDROCARBON BINARIESThe experimental results reported by Kohn (5, 6) and by Stalkup and Kobayashi ( I 7 ) and in this paper indicate that the binary pha* behavior of methane with other nparaffin hydrocarbons through n-decane offers at least three types of phase behavior:1. S stems in which the critical locus runs continuously higher boiling constituent with complete liquid phase miscibility.2. Systems in which the critical locus runs from the critical of the higher boiling constituent to a liquid-liquid from t E e critical of pure methane to the critical of the Lewis J. Hurt is at Rohm and Haas Company, Huntsville, Alabama.critical locus occurring at a temperature below the critical temperature of pure methane and at a pressure considerably in excess of the critical for pure methane; that is, when a liquid-liquid-solid-gas quadruple point occurs in the binary system.3. Systems in which the critical locus starting from the critical of the heavier component is severed by the intrusion of the solid-liquid-gas phase relationship upon the vapor-liquid equilibrium region, giving a second critical locus which extends from the critical point of pure methane to a gas-liquid critical point with solids present.These three types of systems are exemplified by the pressure-temperature projection of the methane-propane, methane-n-heptane, and methane-n-decane systems, respectively, as shown in Figures 1, 2, and 3.It has been verified experimental...
the diffusivity decreases very rapidly as concentration increases in the dilute region, but becomes much less dependent on concentration in the concentrated region.Refractive indices of nickel ammonium sulfate solutions were measured at 25" C. with an Abbe refractometer. The instrument was capable of measuring refractive index with a precision of +~0.00005 (Table 11).
TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractBased on encouraging results from laboratory studies described in SPE 62610 (
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