Generated 11.02.2012
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Generated 11.02.2012 |
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| NPDID wellbore: | 3772 | |
| Well name: | 25/8-12 | |
| Drilling operator name: | Esso Exploration and Production Norway A/S | |
| Geodetic datum: | ED50 | |
| Coordinates: | 59° 17` 22.57`` N | 2° 26` 39.45`` E |
| UTM coordinates: | 6572584.32 N | 468340.44 E |
| UTM zone: | 31 | |
| Drilled in production licence: | 027 | |
| Area: | NORTH SEA | |
| Discovery: | 25/8-11 RINGHORNE | |
| Field: | BALDER | |
| Drill permit: | 955-L | |
| Drilling facility: | MÆRSK JUTLANDER | |
| Drilling days: | 6 | |
| Wellbore entry date: | 09.06.1999 | |
| Wellbore completion date: | 19.06.1999 | |
| Original wellbore purpose: | APPRAISAL | |
| Wellbore purpose: | APPRAISAL | |
| Wellbore status: | P&A | |
| Wellbore contents: | OIL | |
| Discovery wellbore: | NO | |
| Formation/age with hydrocarbons 1: | STATFJORD FM / EARLY JURASSIC | |
| Seismic location: | ||
| Kelly bushing elevation (KB) [m]: | 23 | |
| Water depth [m]: | 127 | |
| Total Depth (MD) [m]: | 2156 | |
| Final vertical depth (TVD) [m]: | 2083 | |
| Max inclination [°]: | 24.90 | |
| Bottom hole temperature [°C]: | 85 | |
| Oldest penetrated age: | LATE TRIASSIC | |
| Oldest penetrated formation: | SMITH BANK FM | |
| Note: All depths, except the water depth, are relative to kelly bushing (RKB) | ||
General
Well 25/8-12 A is a sidetrack from well 25/8-12 S, which encountered oil in Lower Jurassic, Upper Statfjord Formation sandstones. It was drilled to appraise the southern extension of the 25/8-11 Ringhorn discovery. In the Ringhorn structure, the BCU is also the base of the chalk and represents the overall top of the Lower Jurassic reservoir interval. The primary objective for well 25/8-12 A was Lower Statfjord Formation sandstones, in an eroded horst, fault block.
Operations and results
Appraisal well 25/8-12 A was drilled with the semi-submersible installation "Mærsk Jutlander". It was kicked of from 1014 m in the 8 1/2" section of 25/8-12 S on June 9, 1999 and drilled to TD at 2156 m in the Triassic Smith Bank Formation. The wellbore was drilled with oil based "Environment" mud. Top Statfjord Formation was found at 1945.7 m (1863.1 m TVD SS). Oil was encountered in Lower Statfjord Formation sandstones, as prognosed. Pressures and fluid sampling was undertaken with Schlumberger's Modular Dynamic Tester (MDT). Pressure measurements gave an oil gradient of 0.0719 bars/m (0.318 psi/ft), consistent with the oil gradient in the original 25/8-12 S wellbore (0.0749 bars/m) and in the 25/8-11 well (0.0741 bars/m). The oil and water gradients intersect to give an OWC at 1917.5 m TVD SS (2005 m MD RKB), in agreement with the Free Water Level defined in the 25/8-11. The deepest sands in the wellbore, the water bearing sands below 1970 m TVD SS, appear to record a separate, higher reservoir gradient. Four oil samples were collected in 450 cc MDT chambers at 1975 m, within the main Jurassic sand reservoir. No draw down was seen during the sampling. Temperature (measured, not static) ranged from 78.4 deg C to 79.3 deg C during the sampling. In addition to the 450 cc chambers, a single one-gallon chamber was filled with oil at the same depth. A one-gallon water sample was obtained at 2008.2 m. One core was cut in the interval 1951 - 1988.5 in the Statfjord Formation. Well 25/8-12 A was permanently abandoned on June 19 1999 as an oil appraisal well.
Testing
No drill stem test was performed
Interval [m]: 1600.00 - 2156.00
Core length [m]: 37.50
| Core number | Interval |
|---|---|
| 1 | 1951-1988.5 |
 1951-1956m |
 1956-1961m |
 1961-1966m |
 1966-1971m |
 1971-1976m |
 1976-1981m |
 1981-1986m |
 1986-1989m |
No oil samples available.
| Type | Casing diam. [inch] | Depth below KB [m] | Hole diam. [inch] | Hole depth below KB [m] | Lot mud eqv. [g/cm3] |
|---|---|---|---|---|---|
| CONDUCTOR | 30 | 211.0 | 36 | 213.0 | |
| INTERM. | 9 5/8 | 990.0 | 12 1/4 | 990.0 | |
| OPEN HOLE | 2156.0 | 8 1/2 | 2156.0 | 1.62 |
| Depth MD [m] | Mud weight [g/cm3] | Visc. [MPa.s] | Yield [pnt Pa.] | Mud type | Date measured |
|---|---|---|---|---|---|
| 825 | 1.32 | 30.0 | OIL (ENVIRON) | ||
| 860 | 1.33 | 30.0 | OIL (ENVIRON) | ||
| 1340 | 1.32 | 30.0 | OIL (ENVIRON) | ||
| 2156 | 1.32 | 27.0 | OIL (ENVIRON) |
No drill stem test in this wellbore.
| Log type | Intervals logged [m] |
|---|---|
| MWD - DIR | 153 - 213 |
| MWD - EWR4 DGR | 213 - 2156 |
| AIT-H DSI IPLT GR | 986 - 2160 |
| MDT GR | 1948 - 2064 |
| VSP | 300 - 2150 |
| Top depth [m] | Litostratigraphic unit |
|---|---|
| 150 | NORDLAND GP |
| 560 | UTSIRA FM |
| 672 | NO FORMAL NAME |
| 728 | HORDALAND GP |
| 728 | SKADE FM |
| 954 | NO FORMAL NAME |
| 1155 | GRID FM |
| 1166 | NO FORMAL NAME |
| 1748 | ROGALAND GP |
| 1748 | BALDER FM |
| 1815 | SELE FM |
| 1875 | LISTA FM |
| 1915 | VÅLE FM |
| 1921 | SHETLAND GP |
| 1946 | NO GROUP DEFINED |
| 1946 | STATFJORD FM |
| 2028 | NO GROUP DEFINED |
| 2028 | SMITH BANK FM |
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Composite log (Format:PDF. Size: 0.384 Mb) |
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No geochemical data presently available. Regional geochemical studies which include data from this well may however be filed on a different well.
No documents presently available.
