2010-08-27_REPORT - M1983194 - Laserfiche WebLink

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Elevated Conductivity Levels in BG-5 Groundwater Samples Prepared for Natural Soda, Inc. By Daub & Associates, Inc. Introduction The Natural Soda, Inc. BG-5 (12H-C) was a vertically drilled exploration core hole, drilled in the Parachute Creek and Garden Gulch Members of the Green River Formation in the Piceance Basin of western Colorado. The core hole is located on U.S. Department of the Interior, Bureau of Land Management property in the SE quarter of the SE quarter of Section 26, Township 1 South, Range 98 West, in Rio Blanco County, CO. The as-built location is 39° 55' 44.89886" North latitude, 108° 21' 04.03445" West longitude, referenced to NAD 27. The as-built ground elevation is 6,683.4 feet above mean sea level. Depths mentioned in the text are reported relative to ground level. The core hole was originally named 12H-C. The primary objective of the 12H-C core hole was to provide stratigraphic control on the Boies nahcolite bed in support of the 11 H-I well plan, as well as to further define the saline mineral facies and saline zone interval at this location for future development. After coring operations, the 12H-C was plugged back successfully and completed as a groundwater monitoring well in the B-Groove Aquifer, and is now known as the BG-5. Drilling operations began on August 7, 2009 with the drilling of the conductor and pre-core drill holes. Coring operations began on August 14, 2009 and were completed on August 25, 2009. Following spot coring operations from 1450 to 1505 feet the hole was reamed and drilled ahead to 1870 feet with a 6 inch bit and 1870 feet of HWT temporary casing was installed. Attempts to core from 1870 to 2022 feet were problematic, with 2 bits burnt or otherwise destroyed, due to a split in the drill pipe. It was noted that while coring, below the Dissolution Surface (DS), between 1920 and 2022 feet there were no returns and that approximately 280 barrels of high total dissolved solids (TDS), polymer mud was lost to the formation. Note that the DS Aquifer has very high levels of TDS. At 2022 feet the HWT temporary casing was pulled and the hole was reamed to 2022 feet with a 6 inch bit. Lost returns during these reaming operations were approximately 150 barrels. HWT temporary casing was set to 2022 feet and the well was cored from 2022 to 3005 feet with losses of approximately 450 barrels of drilling fluid. The core hole was plugged back from a total depth of 3005.0 feet to 1645.0 feet. A total of 160 sacks of Portland 1/II cement, approximately 1200 gallons, were used in the plug back operations. Abundant drill/core cuttings were noted in returns to surface during corehole plugback operations. It was felt that these cuttings may have become lodged between the HWT temporary casing and the borehole wall, possibly indicating a poor seal at the bottom of the HWT liner. A poor seal at the bottom of the HWT liner may have allowed an alternate pathway, for a minor amount of high TDS drilling/coring fluids, up the annular spaces and possibly into the B-Groove aquifer. Cement plugback batches were followed by flushes of water hauled from the 90-1 water supply well. The quality of the cement plug is good and considered impermeable. The hole was sanded back from 1645 to 1604 feet prior to intermediate casing installation and cementing operations. The 4.5 inch OD J-55 steel intermediate casing was installed at a depth of 1601.2 feet. The intermediate casing was cemented to surface by Halliburton on September 3, 2009. On September 12, 2009, Halliburton mobilized to the site to run a cement bond log (CBL). The CBL was successfully run from 1600 feet to the surface. Analysis of the CBL determined that the casing was properly cemented and the overlying aquifers sealed. The open hole interval for this B-Groove monitoring well is 1604 to 1645 feet. The B-Groove stratigraphic interval is located from 1614 to 1634 feet BGL. Daub & Associates, Inc. 13G-5 GW Sampling Anomaly 8-24-10 rgd Printed: 8/24/2010 Page 1 of 15