Adverse Effects of Mineral-Alkali Reactions in Alkaline Flooding: A Reappraisal, Project BE4B, FY89.

摘要

An analysis is presented of data from experiments on mineral-alkali reactions. The most informative experiments consisted of injection into ''slim tubes'' containing crushed sand: (1) NaOH into a high-clay sand, and (2) Na sub 2 CO sub 3 into a low-clay sand. A fast (ion exchange) reaction occurred in both experiments, consuming 42% and 4% of the alkalinity in a 1-PV slug, respectively for 1 and 2. A slow (dissolution-precipitation) reaction consumed about the same proportions, but ceased in 2 and continued indefinitely in 1. Peaks of sodium, calcium, and magnesium concentrations in the effluent of 1 prior to expected breakthrough are unexplained, but may be partly associated with pre-saturation with KCl and the presence of K-feldspar. Relative timing of Si and Al effluent profiles suggest two precipitation reactions with different Al/Si stoichiometry. The failure of simple equilibrium calculations to account for alkalinity, pH, and concentrations of calcium and carbonate in the effluent from 2 indicates complex equilibria or slow kinetics. 2 refs., 14 fig., 18 tabs. (ERA citation 14:024055)