2011-01-03_GENERAL DOCUMENTS - P2008043 (3)

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To Pile Page k May 28, 1985 The 1980 Drilling Program began on November 17, 1980 and ended on December 15, 1980. Copies of drilling tickets and invoices for the 1980 program were obtained from Mateti Exploration, drilling contractor on the project. Based on these documents, the program used a high-yield sodium bentonite gel with brand names of Petroplus Gel or Bed Devil Gel as a hole abandonment mud. The mud was used on an average rate of .089 lbs/foot of hole. Mixing and circulating took approximately 20-30 minutes per hole. Existing records do not indicate what the final mud weight or viscosity was. However, Bob Timmer, currently with Mobil in Midland recalled that a viscosity measuring funnel was used at least on an occasional basis. He could not recall what the character of final product was. An attachment to a 1977 letter from Charlie Greenberg to the State of South Dakota (attached, Fig. 7) described a Mobil hole abandonment procedure in which the abandonment fluid would have a weight of nine pounds per gallon and a tunnel viscosity of 45 seconds/quart. it should be noted that in a recent telephone conversation, Marti Gardner, mud engineer with Advanced Fluid Systems, Denver indicated that, as a rule of thumb, when mixed solely with water, Petroplus Gel and Red Devil Gel are required at a rate of approximately .5 lbalfoot of hole for a five inch diame- ter hole in order to meet current Wyoming standards. Although this is consid- erably more than our 1980 usage, Bob Goble, with Western Exploration, indicated that over our 1980 usage was consistent with industry practice at the time. In addition, if we mixed the gel with natural, formation mud from the drilling, we would have obtained a higher viscosity that if we had mixed the gel with water. in his letter of April 13, 1981 (attached Fig. 8) to Linda Walker (MLR) Bruce Norton, Field Coordinator for Mobil stated that "No artesian flow was encoun- tered in any hole. All holes were plugged from bottom to within ten feet of surface with a high viscosity drilling fluids". A cement surface plug was installed from the top of the mud plug (ten feet below the surface) to within two feet of the surface or to the surface, depend- ing on local cultivation practices. Invoiced cement usage of slightly more than one bag per hole is consistent with this surface plug installation. Based on the above findings, it appears that mobil plugged the drill holes in a manner consistent with the procedure approved by Bretz of the State Board of Land Commissioners. However, it is uncertain if it complies with the wishes of the Mined Land Reclamation Board. 1.978-r9 PF . Applicable Standards Page 2 of the 1978-79 program permit (Colorado Prospecting Permit NO. 665) states with regard to hole plugging: 4