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Home My WebLink About2010 Pretty CreekChevron February 28, 2011 Chantal Walsh Petroleum Engineer Mid Continent/Alaska SBU Chevron North America Exploration and Production 3800 Centerpoint Dr., Ste 100 Anchorage, AK 99503 Tel (907) 263-7627 Email walshc@chevron.com ECC ME Mr. Dan Seamount, Chairman MAR no Oil and Gas Conservation Commission 333 W. 7th Avenue, Suite 100 �� + � Anchorage, AK 99501 J SiDn Re: 2010 Annual Performance Report: Material Balance Calculations of Production and Injection Volumes Pretty Creek Gas Storage Facility Pretty Creek Unit #4 Dear Commissioner Seamount: Attached for your review is the 2010 "Annual Performance Report" for the Pretty Creek Gas Storage Facility - Pretty Creek Unit #4 (PCU#4), as required by AOGCC Storage Injection Order No. 4 (SIO#4). This report contains material balance calculations of production and injection volumes from the inception of primary production, through 2010 gas storage operations. Attachment #1 is a table of monthly gas production and injection volumes for the PCU#4 well through February 21, 2011. The table includes all production and injection volumes beginning with the commencement of primary production in December 2001. Note that from December 2001 through April 2004, primary production was from both the 51-5 and from the 45-0 reservoirs. It is estimated that 1.286 Bcf of gas was produced from the 45-0 sand. On May 1, 2004, the 45-0 sand was isolated and the remaining primary production, as well as all gas storage operations (beginning in Nov. 2005), was from the 51-5 sand. Gas injection was initiated into the 51-5 sand in PCU#4 on November 15, 2005 and by July 1, 2007 the reservoir was within approximately 0.14 Bcf of being full. From October 2007 through July 2009, the 51-5 gas storage reservoir was cycled twice. Approximately 21 MMcf of gas was produced during the 2009/2010 winter, and 556 MMcf of gas injected into the storage reservoir during the summer of 2010. The 2010 summer injection filled the 51-5 reservoir to approximately .5 Bcf above its original gas in place. The daily rate performance of the well has improved and the response of the reservoir over this winter season has been following the projected trends. Attachment #2 is a table of calculated reservoir pressures over the life of the storage operation, with the associated cumulative gas voidage (production - injection) at the time of the pressure estimates. These pressures (divided by their respective Z -factors) are plotted versus net cumulative gas withdrawn on a standard P/Z plot (Attachment #3). Viewing the P/Z plot (Attachment 3), the 2010 injection cycle data shows that the 51-5 reservoir was filled above the initial reservoir volume. The injection cycle shows it follows MidContinent/Alaska SBU/Chevron North America Exploration and Production www.chevron.com Pretty Creek Gas Storage Facility 2010 Annual Performance Report Page 2 the trend from the previously established injection curve of 2005 through 2007. This is a good indication that storage operations within the 51-5 reservoir have been contained. If you have any questions regarding this annual performance report, please contact Chantal Walsh at your earliest convenience. Sincerely, Chantal Walsh Petroleum Engineer Cc: Dave Whitacre Attachments Union Oil Company of California / A Chevron Company http://www.chevron.com ATTACHMENT #1 PCU #4 PRODUCTION AND INJECTION VOLUMES Primary Production from both 51-5 and 45-0 Sands - Cumulative gas produced from the 45-0 Sand = -1,286 MMcf Gas Storage (since Nov. 2005) only in 51-5 Sand Month Monthly Gas Prod MCF Monthly Gas Inj MCF Cum Gas Withdrawn MCF Month Monthly Gas Prod MCF Monthly Gas Inj MCF Cum Gas Withdrawn MCF December -01 80,465 - 80,465 January -02 195,929 - 276,394 January -06 - - 2,719,005 February -02 196,257 - 472,651 February -06 - - 2,719,005 March -02 220,869 - 693,520 March -06 - 104,423 2,614,582 April -02 165,533 - 859,053 April -06 - 163,320 2,451,262 May -02 26,375 - 885,428 May -06 - 3,281 1 2,447,981 June -02 31,104 - 916,532 June -06 255 - 2,448,236 July -02 10,746 - 927,278 July -06 263 - 2,448,499 August -02 - - 927,278 August -06 263 - 2,448,762 September -02 33,163 - 960,441 September -06 878 169,962 2,279,678 October -02 183,163 - 1,143,604 October -06 - 140,560 2,139,118 November -02 157,256 - 1,300,860 November -06 2,983 96,880 2,045,221 December -02 138,233 - 1,439,093 December -06 - 120,096 1,925,125 January -03 117,103 - 1,556,196 January -07 49,440 85,109 1,889,456 February -03 85,932 - 1,642,128 February -07 3,706 85,162 1,808,000 March -03 79,775 - 1,721,903 March -07 58,089 74,450 1,791,639 April -03 17,030 - 1,738,933 April -07 - 184,212 1,607,427 May -03 196 - 1,739,129 May -07 - 116,641 1,490,786 June -03 - - 1,739,129 June -07 - 64,573 1,426,213 July -03 25,313 - 1,764,442 July -07 - - 1,426,213 August -03 20,306 - 1,784,748 August -07 - - 1,426,213 September -03 16,087 - 1,800,835 1 September -07 - - 1,426,213 October -03 9,758 - 1,810,593 October -07 339 - 1,426,552 November -03 3,544 - 1,814,137 November -07 94 - 1,426,646 December -03 52,856 - 1,866,993 December -07 37,071 - 1,463,717 January -04 57,353 - 1,924,346 January -08 99,982 - 1,563,699 February -04 55,318 - 1,979,664 February -08 107,659 - 1,671,358 March -04 45,931 - 2,025,595 March -08 634 - 1,671,992 April -04 - - 2,025,595 April -08 283 - 1,672,275 May -04 56,583 - 2,082,178 May -08 - 128,809 1,543,466 June -04 70,263 - 2,152,441 June -08 - 114,230 1,429,236 July -04 21,267 - 2,173,708 July -08 - 105,813 1,323,423 August -04 74,030 - 2,247,738 August -08 290 1,636 1,322,077 September -04 41,208 - 2,288,946 September -08 9,220 15,228 1,316,069 October -04 83,626 - 2,372,572 October -08 122 - 1,316,191 November -04 80,884 - 2,453,456 November -08 73,656 - 1,389,847 December -04 71,571 - 2,525,027 December -08 201,815 - 1,591,662 January -05 62,310 - 2,587,337 January -09 215,323 - 1,806,985 February -05 54,328 - 2,641,665 February -09 84,921 - 1,891,906 March -05 55,460 - 2,697,125 March -09 - - 1,891,906 April -05 57,247 - 2,754,372 April -09 66 - 1,891,972 May -05 53,045 - 2,807,417 May -09 37 194,423 1,697,586 June -05 40,800 - 2,848,217 June -09 - 206,712 1,490,874 July -05 40,964 - 2,889,181 July -09 - 211,061 1,279,813 August -05 37,981 - 2,927,162 August -09 - - 1,279,813 September -05 8,872 - 2,936,034 September -09 - - 1,279,813 October -05 - - 2,936,034 October -09 - - 1,279,813 November -05 - 59,329 2,876,705 November -09 - - 1,279,813 December -05 - 157,700 2,719,005 December -091 390 1 11280,203 ATTACHMENT #1 PCU #4 PRODUCTION AND INJECTION VOLUMES Primary Production from both 51-5 and 45-0 Sands - Cumulative gas produced from the 45-0 Sand = —1,286 MMcf Gas Storage (since Nov. 2005) only in 51-5 Sand Month Monthly Gas Prod MCF Monthly Gas Inj MCF Cum Gas Withdrawn MCF January -1 0 250 0 1,280,453 February -10 19,633 0 1,300,086 March -10 330 0 1,300,416 April -10 270 0 1,300,686 May -10 0 0 1,277,862 June -10 14 22,824 1,124,093 July -10 1,919 153,783 964,371 August -1 0 0 161,641 815,322 September -10 0 149,049 744,716 October -10 0 70,606 718,076 November -10 181,010 26,640 899,086 December -10 349,804 0 1,248,890 Monthly Monthly Cum Gas Gas Gas Month Prod Inj Withdrawn MCF MCF MCF C N E E U O Z N N aNi F- N 75 O O U o n 9 O tRS Edi N E o > L CO N 7 N O N O a Ud (v a �— J U Z N o Lu N a N a � U � � E Z cp �t m fA � @ J .� j � Q N � � d L N U N N 0 0 o o N _t O Z N N aNi F- N 75 O o n 0 C a N ro E v o m a o Ev a N a v o o 0 c o G E E E E E E E .� E S S O ~ n° o _t 0° NON m l 3 N _ d N 0 0 ° O ° m N N N N [L o to MD O C Lo V R 'Tr V N O - 5 - - 5 5 - 5 5 g L 5 5 'o (D N M M. 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