December 14,2008 United States Nuc I e a r Regu Ia to ry Coni m iss io 11 Region IV - Materials Inspection Branch 61 1 Ryan Plaza Drive, Suite 400 Arlington, Texas 7601 1 RE: Source Abandonment for EnCana 011CU: Gas (USA), Inc.: Stud Horse Butte 76-28 Dear Sir or Madam: This letter is to confirm the a5andoiiment ai irreI.riwi!jle saur~esin a well in accordance with Part 39, Section 39.77(d). !nfcjrmation for this abandoniiieiit IS atthched. If you have any questiuns or require add15m;1/information, please contact me at 281-285-7460. Thomas S. Wood Deputy Radiation Safety Officer Sc h Iu m b e rg e I. Te c h n o I o g y Corporation Source Abandonment - EnCaiia Oil & Gas (USA), Inc. Well: Stud Horse Butte 76-28 Date of Occurrence: December 4,2008 Source #1 Identification: 592 GBq (16 Ci), Am241 Be, Neutron Source, Serial # G5146 Manufacturer: Ga mm atro n, Inc . Model: NSR-F (AN-HI‘) Depth: 8,193’ MD Source #2 Identification: 63GBq (1.7 Ci), Cs 137, Density Source, Serial # A5367 Manufacturer: QSA Global, Inc. Model: CDC.CY3 (GSR-J) Depth: 8,206’ MD WeII Identification: Company: EnCana Oil & Gas (USA), Inc. Well: Stud Horse B~itte16-28 Fie Id: Jonah County: Sublelte Stat e : Wyo rn in g API Number: 49-035-26944 Seal Results: 216’ of Class G, 14.5 ppg cement with Red Oxide Dye spotted in the annulus above the drill pipe and logging tool from 6,969’to 6,753’. A 847’ kick off plug of Class G, 17.5 ppg cement was set from 6,691’to 5,844’. In addition to the - 1,211’ of heavy weight drill pipe, collars, fishing assembly and logging tool remaining on top of the sources from 6,969’to 8,180’, the casing liner set above the cement plug at the KOP will serve as the mechanical deflection. Recovery Attempts: Multiple attempts from 11/23/08 to 12/4/2008 Depth of Well: 12,445’ Identification: Plaque as required by Part 39 ordered and will be attached to the well. Reports: No other agency will receive a copy of this report. Initial Telephone Mr. Charles Cain, NRC-Region IV on l1/28/08 @ 14:OO CST. Contact: 0 Offshore (OCS Waters) Land or State Lease Waters Date: December 4, 2008 Time: 14:20 Company Name (Full Name): EnCana Oil & Gas (USA), Inc. Well Name or (OCS-G No. or State Lease No.): Stud Horse Butte 76-28 Offshore State of: Rig Name: Ensign 125 API Number (If Available or CLSD): 49-035-26944 Field Name: Jonah Lease Location (legal): se/sw 28-29n-108 County or Parish: Sublette State: Wyoming District: Rock Springs Sales Engr: Eric Borchardt TD: 12,445 ft Hole Size: 7.88 in Deviation: 0 Casing Depth: 2,501 ft Casing Size: 9.625 in Depth of Fish (Top): 6,969 ft Bottom of Fish: 8.224 ft Source Type (1): NSR-F Source Type (2): GSR-J Source Activity (11: 592 GBq Source Activity (2): 63 GBq Serial No. (1): NSRF ~5146 Serial No. (2): GSR-J A5367 Isotope (I): Am-241 Be Isotope (2): Cs-I37 Depth (11: 8,193.5 ft Depth (2): 8,206.7 ft Leak Test Date (1): 08/25/2008 Leak Test Date (2): 06/25/2008 Leak Test Results (1): 3.409E-001 Bq Leak Test Results (2): 1.579E-001 Bq Tool String (Head to Bottom): LEH-QT/ DTC-H/ HGNS-H/ HRCC-H/ HRMS-H/ AIT-M Date and Time Stuck: November 23, 2008, 17:OO Date and Time Cement Pumped: December 4 @, 06:30 Hole Conditions: Hole conditions were reported ok by client before starting operations. Fishing Attempts: Went down with pipe and overshot and cable became free at 8,300'. Tool was pull into overshot but pipe became stuck at the same point. Broke weak point. Client ran temp log twice and free point tool. Perforated at 6,500', 6,000', 5,500' and 4,500' to regain circulation Back-off at 2,460', jarred, back-off at 6,000', jarred and back-off at 6,950'. Jarred but not ok. Comments (what happened to get stuck?, etc.,): Logging down with PEX-AIT and bridged at 11,560'. Pulled up around 100' with some pulls on head and cable. After reaching normal tension started RIH again and noticed after a few seconds that the cable was stuck (no change in head tension and surface tension going down). Pulled up to maximum safe pull without changing in head tension and informed the client and FSM. After doing stretch calculation noticed that the cable was stuck at around 4,000 ft. NOTE: Regulatory agencies should be contacted ONLY by the Schlumberger Technology Corporation (STC) Radiation Safety Officer or, if unavailable, his designee. Page 1 of 2 Rev 7/08 Notified: E! NRCor Stateof: Region IV - NRC Name: Mr. Chuck Cain Name: Date: 11/28/2008 Date: Time: 14:OO CST Time: The following is a summary of NRC and/or Agreement States regulations that must be followed when abandoning an irretrievable well logging source(s). The specific regulations are found in 10 CFR 39.15 and equivalent regulations in Agreement States. An irretrievable well logging source means any licensed radioactive sealed source that becomes lodged in a well and cannot be retrieved after reasonable efforts have been made to recover the source(s). 1. If a well logging source is irretrievable, the following requirements must be implemented. a) The source(s) must be immobilized and sealed in place with a cement plug. The cement has to be dyed red in Texas as a condition of the Texas Railroad Commission (others occasionally). b) A mechanical deflection device must be set at some point in the well above the cement plug to prevent inadvertent intrusion on the source, unless the cement plug and sources(s) are not accessible to any subsequent drilling operations. The mechanical device can be devices such as a whipstock, old drill bit, etc. For LWD, drillpipe and/or collars left on top of the BHA usually are approved as a deflection device. c) A permanent identification plaque, (supplied by the STC RSO) made of stainless steel (or brass, bronze and monel), must be mounted at the surface of the well unless the mounting of the plaque is not practical (i.e. subsea completion). 2. The STC RSO (or his designee) will notify the NRC or Agreement State of the abandonment plan developed by/with the client. The NRC or Agreement State must approve the abandonment plan prior to implementation. The federal and/or state oil and gas well permitting agency must also approve the abandonment plan. The contact with the well permitting agency is the responsibility of the well owner/client but we should advise him/her of that fact as a courtesy. 3. If any changes must be made to the abandonment plan submitted to the NRC or Agreement State, the STC RSO must be informed so that he/she can get approval of the modification, as appropriate. The actual abandonment must not begin until any abandonment plan or modification to that plan is approved by the appropriate agency. 4. The STC Radiation Safety Officer must file a written report with the NRC or Agreement State after the abandonment. The facility management shall file a written report within 7 days to the STC Radiation Safety Officer. The facility report should cover the final abandonment details such as: a) Actual date of abandonment. b) Any changes in the data sent with the approved abandonment plan. c) Detailed Well Schematic depicting location and depth of tool(s), source(s), drill pipe, plugs, deflection device etc. d) Any information pertinent to the abandonment that the STC RSO may not have for his/her final report. e) If all data sent to the STC RSD is still applicable for the final report, an e-mail or fax is to be sent to the STC RSO confirming that fact so that he/she can be ensured that the data sent to the appropriate agency is totally accurate. Most facilities send a completely new report since many these documents often are incomplete or are poor quality fax reproductions. If there are any questions regarding these procedures, discuss them with your Operations Manager. FACILITY MANAGEMENT MUST ENSURE THAT THE FINAL ABANDONMENT REPORT IS SUBMITTED TO THE STC RADIATION SAFETY OFFICER. Page 2 of 2 Rev 7/08 Wellbore Casing/ Diagram Hole Size 9 5/8" Csq @. 2.501 ' 5,844'Top of Cement Plug 6,753'Top of Cement Plus 6,969'Top of Fish 8,180'Top of Tool TD @ 12,445' MD Customer Job Number 1 ENCANA USA - DENVER, FOR XML BlLLlN 2207161068 Well Location (legal) Schiumberger Location Job Start STUD HORSE BUTTE 76-28 Rock Springs, WY 2008-Dec-04 Field Formation NamelType Deviation Bit Size Well MD Well TVD JONAH ' 7.88in 6,900 ft 6,900 ft County StatelProvince Pore Press. Gradient Sublette WY BHP osi BHS:63'F BHC:27"F Dsi/fl I I 1 I I Well Master: 0630797256 API I uwi: CasinglLiner Rig Name Drilled For Service Via Depth,& Size, in Weight,lblft Grade Thread ENSIGN 125 Gas Land 1 Offshore Zone Well Class Well Type New Development TubinglDrill Pipe Drilling Fluid Type Max. Density Plastic Vi! cp Depth, Size, in Weight, IbM Grade Thread Other 10.1 Ib/aal 6961 I 4.5 I 16.6 I Service Line Job Type Cementing Set Cement Plug P/W PerforationslOpen Hole Max.