Relinquishment Report. Block 48/11c

Transcription

1 Relinquishment Report Petroleum Production Licence No. P.1008 Block 48/11c EOG Resources United Kingdom Limited

2 List of Contents 1. Licence information 2. Synopsis 3. Exploration Activities 4. Prospectivity analysis 5. Reserves 6. Figures List of Figures Figure 1 Figure 2 Figure 3 Block Location Map Top Rotliegendes Depth Map PreSDM Seismic Dip Line

3 1. Licence information Licence number P.1008 Blocks/area 48/11c Licence Round 18th Round Licence award date 23 December 1998 Licence type Traditional Production License Partners EOG Resources United Kingdom Limited 40.2% Perenco United Kingdom 53.3% Marubeni 6.5% 2. Synopsis EOGUKL acquired 50% interest in Block 48/11c through acquisition and transfer of interests from ExxonMobil Corporation UK (hereinafter ExxonMobil ) in March 2006 (Figure 1). The area had been identified due to the Glein gas discovery from the Permian Rotliegendes sandstone (Leman). Work done by ExxonMobil and Perenco at this time had further identified a prospective Rotliegendes trend (West Malory, subsequently renamed Eos) across the block (Figure 2). A 3D survey PreSDM was reprocessed by Perenco and results of mapping demonstrated a low relief structure (within highlighted area in Figure 3) in the Rotliegendes, Leman sandstone. The structure is elongate, in a NW-SE direction, and straddles Blocks 48/11c and 48/11a. It is also on trend with the Malory Field (Rotliegendes). Within the structure it was established that there were two separate structural culminations, one in 48/11a and the other in 48/11c. In June 2007 a unitization and unit operating agreement was put in place between Block 48/11a and Block 48/11c licensees, (resulting in unit equities of Perenco 53.3%, EOG 40.2%, Marubeni Oil and Gas (U.K.) Limited (hereinafter Marubeni ) 6.5%) and a work program of one firm well and a contingent well was agreed in order to test the undrilled Eos (formerly West Malory) prospect. Furthermore, in consideration of the structure crossing block boundaries, DECC agreed that one well into the structure would satisfy activity conditions and deem Block 48//11a and Block 48/11c as not Fallow. Both blocks had been declared Fallow in January The initial exploration well s purpose was to prove presence of gas in the Rotliegendes reservoir, assess its deliverability, and aid in field development planning. The contingent well, was to be a sidetrack that would be completed and tested in the event of success with the initial well. On July 11 th 2007, 48/11c-13 was spudded. The location of the well was placed within Block 48/11c and then deviated southeast into the highest point of the structure situated in Block 48/11a. The well had gas shows, but the structure at that time, was considered to not contain commercial volumes to justify the drilling contingent well and full field development. Given the negative results, EOG and partners concluded that no further evaluation was to be undertaken. The block was subsequently relinquished in December 2007.

4 3. Exploration Activities Reprocessing of 3D PreSDM seismic Drilled 48/11c-13 Eos exploration well 4. Prospectivity Analysis EOGUKL and partners mapped the Lower Permian Rotliegendes (Leman) sandstone using PreSDM seismic over 48/11c and 48/11a. The mapping revealed a low relief structure that was fault and dip closed, with sealing by evaporites of the Upper Permian Zechstein Group. Additional horizons were also mapped (Red Chalk, Corallian, Top Triassic, Bunter, Zechstein, Platten Dolomite) to help ascertain validity of the structure, in consideration of the complexity due salt in the overburden. Mapping also recognized that the prospect consisted of two potentially separate accumulations. Consequently, EOGUKL conducted a review of all the key wells in the area. This was to demonstrate that the Rotliegendes sandstone was of adequate reservoir quality. A risk was that the sandstone had undergone deep burial and uplift as seen in adjacent areas, which considerably affected attributes of the rock. Henceforth, each well was reviewed using electric logs, mud logs, well tests, and end of well reports. Core analysis and extensive petrophysical analysis was also completed and incorporated with reservoir facies mapping across the block. The technical evaluation of the Rotliegendes (Leman) trend produced the following outlook for the prospect: Reservoir Parameters: o N:G 80% o Porosity 12% (10-16%) o Sg 58% (50 70%) o Kh 5MD (1-10mD) Productive Facies = Aeolian dune/interdune and marine worked sandstone Expected Hydrocarbons = dry gas Reservoir Temperature = 209 F Reservoir Pressure = expected to be virgin with a.452 psi/ft gradient Depth to Reservoir = -8965ft TVDSS Gas Column = 635ft (top structure to prognosed GWC) Gas/Water Contact = -9600ft TVDSS Initial Production Rate = 50MMSCF/D (1 70MMSCF/D) Gas in Place = BSCF Chance of Success = 41.5% The results of well 48/11c-13 were not in line with pre drilling expectations. The reservoir quality was significantly lower compared to nearby wells, had high water saturations, and negligible gas. Post well review deduced that the gas column may have been breached by the Platten Dolomite touching down on the reservoir at the crest of the structure on the southern tip. Another explanation is that that the Malory Field (to the southeast) may have depleted part of the reservoir. This was a known risk as the Eos prospect was interpreted to be on trend with Malory, and the field had already produced volumes in excess of originally mapped reserves.

5 In conclusion, EOGUKL and partner s block evaluation has significantly downgraded the prospectivity of the block. Moreover, EOGUKL and partners are of the opinion that there are no remaining economic prospects in Block 48/11c. 5. Reserves Summary An estimated amount of 20 BCF recoverable gas reserves remains in the identified Rotliegendes (Leman) structure, straddling Blocks 48/11c and 48/11a. No other reserves on 48/11c have been recognized. 6. Figures Figure 1 BLOCK LOCATION 48/11c

6 Figure 2 TOP ROTLIEGENDES DEPTH MAP Contours = 50 feet

7 Figure 3 PreSDM SEISMIC DIP LINE