2013-03-14_HYDROLOGY - P2010026 (4)

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SWEPT LP Executive Summary Well: OW -8124 Purpose: Evaluate the cement bond in the well OW -8124 for the 4 -1/2" casing inside the parted 8- 5/8" casing (2025.1— 2027.6ft). Solution Methodology: Survey the casing with Schlumberger's Isolation Scanner and CBL -VDL Tools General: As part of the UIC permit C03221O- 00000, there is a requirement to conduct corrective actions in the OW -8124 well. The permit ID Number of this well is OB04 (SAW1 Well) and OSE Permit Number is 135 -4- 298 -SAW1. The Corrective Action Plan is described in Appendix F of the permit and requires that Shell a) "Perforate and squeeze cement across the R5 seal from approximate depths of 1,523 to 1,563 feet. Follow with pressure test to ensure well casing integrity." and b) address a 2- 1 /2feet parting in the casing at 2025feet and two 2Ofeet joints in the bottom of the cased interval that are separated from the casing above by installing a 4.5inch casing installed to 2282feet and cemented to surface. The cemented casing will then be pressure tested to ensure well casing integrity. For the part "a" above the 135 -4- 298 -SAW1 well was logged using Schlumberger's CBL -VDL tool on 28- Dec -2009 and Isolation Scanner tool on 19- Jan -2010. Review of these logs indicated poor cement bond characteristics at the R -5 Seal. Shell ran the Schlumberger's Isolation Scanner tool to reassess the condition of the concrete in the R5 interval on 02- Nov -2012 and the conventional CBL -VDL tool on 13- Nov -2012, both the results indicated cement is present in the annulus behind the casing in the R5 interval (1523feet to 1563feet). Therefore there is adequate cement bond to isolate the production zone and the saline water interval from the overlying water bearing intervals. The effective Top of Cement (TOC) is at 962ft. No remedial perforate and squeeze cement across the R5 seal was required. For the part "b" above, the next step of corrective action to address the 2- 1 /2feet parting in the casing at 2O25feet and two 2Ofeet joints in the bottom of the cased interval that are separated from the casing above; a 4.5inch casing was installed to 2284feet and cemented to surface. The cemented casing was pressure tested to ensure well casing integrity. This report is on the cement bond integrity of this newly lowered 4 -1/2" casing inside the 8 -5/8" casing. This cementing of this well involved pumping 3Obbls of Mudpush Express, 81bbls of LiteCrete 9.5ppg cement followed by 18.3bbls of Class G 15.8ppg cement. No issues were reported during cementing and a 15bbls was returned to surface. The Schlumberger's Isolation Scanner cement evaluation service provides more certainty for light weight cements by combining the pulse -echo technique with a new ultrasonic technique that induces a flexural wave in the casing with a transmitter and measures the resulting signal at two receivers. The attenuation calculated between the two receivers provides an independent response that is paired with the pulse echo measurement and compared with a laboratory — measured database to produce an image of the material behind the casing. By measuring radially beyond traditional cement evaluation boundaries, Isolation Scanner service confirms zonal isolation.