2013-03-01_HYDROLOGY - P2010026 - Laserfiche WebLink

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Penetrate Total TOC CAP Well Name Well Type Confining? Depth (ft) Depth (ft) Required (YIN) H02 to H13 (12 wells) Healer Yes 2,285 0 TBD P01 and P02 (2 wells) Production Yes 2,342 0 TBD OB01 and 0B03 (2 wells) Monitoring/ Yes 2,285 0 TBD Backup Injection Wells OB02 Monitoring Yes 2,342 0 TBD 0505 and 0408 (2 wells) Monitoring Yes 2,285 0 TBD The closest mapped fault is the Dudley Bluffs Graben, which is a major structural feature adjacent to the Piceance Creek Dome and in the vicinity of Piceance Creek and Ryan Gulch, that Is a west -north westerly trending structure that terminates approximately three (3) miles east of the East RDD Project. An approximately 1 mile long northerly to northwesterly trending depression (with 20 to 25 feet of vertical displacement and approximately 1/8 mile wide) occurs in the vicinity of the East RDD permit boundary, east and outside of the projected activities. This structure appears to be a primary depression on the lake floor that subsequently was loaded with chemical precipitates — primarily nahcolite and muds with dolomitic composition. Shell has identified all wells within the area permit AOR and there are no drinking water wells or residences. Shell brings in drinking water as needed. Corrective Action Plan (CAP) For wells in the AOR which are improperly sealed, completed, or abandoned, the applicant will develop a CAP consisting of the steps or modifications that are necessary to prevent movement of fluid into USDWs. The OB04 (SAW) well is improperly constructed showing poor cement through the confining zone. Appendix F details the CAP and will be implemented prior to authorization to inject. There are also a number of wells that have not been constructed. After construction, documentation will be provided to EPA for evaluation to make a final determination on whether or not CAP will be required for these proposed wells. Approved Injection Fluid Approved injected fluids are limited to: 1. fresh water (no additives) and reinjection of concentrated brine from the dissolved nahcolite within the Injection zone 2. Inert gas placed in the annulus of the injection and production tubings and longstring casing Shell has proposed injection of an inert gas such as nitrogen that will extend from surface (through the annulus of the tubings and longstring casing) into the leaching interval to control the top elevation of the brine solution. The variable pressurized gas cap will be used to insulate the formation from the injection fluid and help control the upward growth of leaching interval and focus solution mining to . specific horizons. Injection of any hazardous waste as Identified by EPA under 40 CFR §261.3 is expressly prohibited. injection Pressure Limitation Injection pressure, measured at the wellhead, will not exceed the maximum calculated to assure that Permit CO32210 -00000 PART V. Well Operation Requirements (40 CFR §146.23) 11 FINAL PERMIT Statement of Basis