Petrographic examination of Bell Canyon Tests (BCT) 1-FF field grouts over a three-year period

The Bell Canyon field test involving the placement of two grout plugs took place 26 September 1979 (Plug 1) and 14 February 1980 (Plug 2). Samples cast in the field were brought to WES and cured in hole AEC-7 (lease) brine. Samples were examined periodically through 1 year and then at 2- and 3-years age to obtain petrographic, physical, and some chemical data. This report deals solely with the petrographic data. Cracking was believed to be due largely to moisture and temperature changes in the laboratory. The two plugs were similar in composition with the Plug 1 grout having more tetracalcium aluminate monosulfate-12-hydrate and more garnet-hydrogarnet solid solution series material (hydrogarnet) by x-ray diffraction (XRD) than Plug 2. Tetracalcium aluminate dichloride-10-hydrate was present in both samples in varying amounts at different ages. Plug 2 grout contained more ettringite and calcium hydroxide; Plug 1 grout contained more detectable calcium silicate hydrate. The grout to host anhydrite rock bond appeared to be tight with no visible cracking in simulated borehole samples that were examined immediately after fracturing. A white precipitate found on samples of both events during storage and is believed to be a combination of some chemical reaction between the groundwater and grout as well as precipitate from the brine. It had no detectable detrimental effects. Infiltration of the brine during placement of the grout in satellite Holes 3 and 4 weakened the grout and retarded some of the grout so that it did not harden. XRD examinations of both Plug 1 and Plug 2 grouts point out that chloride and carbonate ions from the brine are causing some alteration to the original phases at and near the contact of grout and brine. After 3 years of storage, this alteration has penetrated the grout to a depth of about 1 or 1.5 in. with the severity of alteration becoming less with increasing distance from contact surfaces