Completion Report For Well Er 2 1 PDF Download

Well ER-6-2 and its satellite hole, Well ER-6-2 No. 1, were drilled for the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office in support of the Nevada Environmental Restoration Project at the Nevada Test Site, Nye County, Nevada. Well ER-6-2 was drilled in two stages in 1993 and 1994; the satellite hole, Well ER-6-2 No. 1 was drilled nearby in 1993 but was abandoned. The wells were drilled as part of a hydrogeologic investigation program for the Yucca Flat-Climax Mine Corrective Action Unit Number 97, in the northeastern portion of the Nevada Test Site. The wells are located in Yucca Flat, within Area 6 of the Nevada Test Site. The wells provided information regarding the radiological and hydrogeological environment in a potentially down-gradient position from tests conducted in northern and central Yucca Flat. Construction of Well ER-6-2 began with a 1.2-meter-diameter surface conductor hole, which was drilled and cased off to a depth of 30.8 meters below the surface. A 50.8-centimeter diameter surface hole was then rotary drilled to the depth of 578.5 meters and cased off to the depth of 530.4 meters. The hole diameter was then reduced to 27.0 centimeters, and the borehole was advanced to a temporary depth of 611.4 meters. The borehole was conventionally cored to a total depth of 1,045 meters with a diameter of 14.0 centimeters. Borehole sloughing required cementing and re-drilling of several zones. The open-hole completion accesses the lower carbonate aquifer, the CP thrust fault, and the upper clastic confining unit. A fluid level depth of 543.2 meters was most recently measured in the open borehole in September 2007. No radionuclides were encountered during drilling. The satellite hole Well ER-6-2 No. 1 was drilled approximately 15.2 meters north of Well ER-6-2 on the same drill pad. This was planned to be used as an observation well during future hydrologic testing at Well ER-6-2; however, the satellite hole was abandoned at the depth of 399 meters due to stuck drill pipe, and was subsequently cemented to the surface. Detailed lithologic descriptions with stratigraphic assignments in this report are based on composite drill cuttings samples collected every 3 meters, cores taken between the depths of 619.3 and 1,042.4 meters, and geophysical log data. Stratigraphic assignments within the Paleozoic section are based on paleontological analyses. The well was collared in alluvium and at 30.8 meters penetrated Paleozoic carbonate rocks. These consisted of dolostone with minor shale and limestone of the Bonanza King Formation, and limestone with minor quartzite, sandstone, and dolostone assigned to the Guilmette Formation. The borehole reached total depth in a shale unit assigned to the Chainman Shale. The units below the Bonanza King Formation are overturned due to faulting and folding and, therefore, are stratigraphically upside-down.