Wellbore: 31/4-10 - Factpages - Norwegian Offshore Directorate

General information

General information
Attribute	Value
Wellbore name Official name of wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	31/4-10
Type Wellbore type. Legal values: EXPLORATION, DEVELOPMENT, OTHER (see 'Purpose' for more information)	EXPLORATION
Purpose Final classification of the wellbore. Legal values for exploration wellbores: WILDCAT, APPRAISAL, WILDCAT-CCS, APPRAISAL-CCS. Legal values for development wellbores: OBSERVATION, PRODUCTION, INJECTION, INJECTION-CCS, OBSERVATION-CCS. Legal values for other wellbores: SOIL DRILLING (drilling in connection with track surveys and other subsurface surveys to investigate the soil conditions prior to placement of facilities), SHALLOW GAS (drilling to investigate shallow gas before the first 'real' drilling on the location), PILOT (drilling to investigate the geology and fluid connectors for location of the main wellbore), SCIENTIFIC (drilling according to Law of Scientific research and exploration), STRATIGRAPHIC (driling according to Law of Petroleum activities §2-1).	APPRAISAL
Status Status for the wellbore. Legal values are: BLOWOUT: A blowout has occurred in the well. CLOSED: A development wellbore that has been closed in a shorter or longer periode. Also applies to development wellbores where drilling is completed, but production/injection has not yet been reported. DRILLING: The well is in the drilling phase - can be active drilling, logging, testing or plugging, JUNKED: The drilling operation has been terminated due to technical problems. P&A: Exploration: The well is plugged and abandoned, and can not be reentered for further use. Development wells: The production/injection from/to the well is stopped and the well is plugged. The wellhead is removed or else made unavailable for further well operations. PLUGGED: The wellbore has been plugged, but the upper parts of the wellbore can be re-used. A sidetrack might be drilled at a later stage. PRODUCING: It was produced from the wellbore at the time of the operators last monthly report to the Norwegian Offshore Directorate. INJECTING: It was injected to the wellbore at the time of the operators last monthly report to the Norwegian Offshore Directorate. PREDRILLED: The upper part of the well has been drilled, usually as part of a batch-drilling campaign covering several wellbores. RE-CLASS TO DEV: Exploration wellbore that is reclassified to a development wellbore. RE-CLASS TO TEST: Exploration wellbore that is reclassified to test production. SUSPENDED: The drilling operation in the wellbore has been temporarily stopped. The current plan is to continue drilling later on.	P&A
Multilateral Indicator telling if the parent well is multilateral, meaning it has more than one branch radiating from the main borehole. Example of legal values: YES, NO. See also Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	NO
Factmaps in new window	link
Main area Name of the area on the Norwegian Continental Shelf where the wellbore is located. Legal values: BARENTS SEA, NORWEGIAN SEA, NORTH SEA.	NORTH SEA
Field Name of the field the wellbore is related to.	BRAGE
Discovery Name of the discovery the wellbore is related to.	31/4-3 Brage
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	31/4-10
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	055
Drilling operator Name of the licensee starting the drilling operation on behalf of the active production license (well head position). This will usually equal the operator of the production license.	Norsk Hydro Produksjon AS
Drill permit The drilling permit number together with the version of the drilling permit as stated in the drilling permit granted by the Norwegian Offshore Directorate.	829-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	WEST VANGUARD
Drilling days Number of days from wellbore entry to wellbore completion.	30
Entered date The date when he wellbore was spudded. For sidetracks: The date when new formation was drilled by kicking off from the mother-wellbore,	14.11.1995
Completed date Exploration wellbores from moveable facilities: For floating facilities - date when anchor handling is started. For jackups - date the jacking-down started. Exploration wellbores from fixed facilities and all development wellbores: Date when the wellbore is at total depth, and last casing, liner or screen is set. In case of immediate plugging of the wellbore, completed date equals the date the last plug i set in the wellbore. Date when the wellbore is at total depth, and last casing, liner or screen is set. In case of immediate plugging of the wellbore, completed date equals the date the last plug i set in the wellbore.	13.12.1995
Release date Date when raw data which has been reported to the authorities from the wellbore is not confidential any longer. Normally 2 years after finishing the drilling. May be earlier if the area of the production license is relinquished.	13.12.1997
Publication date Date quality control of the wellbore information was completed, so it can be published on the internet as a 'Well Data Summary Sheet' wellbore with more information available than other wellbores.	06.01.2014
Purpose - planned Pre-drill purpose of the wellbore. Legal values for exploration wellbores: WILDCAT, APPRAISAL, WILDCAT-CCS, APPRAISAL-CCS. Example of legal values for development wellbores: OBSERVATION, PRODUCTION, INJECTION.	APPRAISAL
Content For exploration wellbores, status of discovery. Legal values: DRY, SHOWS (trace amounts of hydrocarbons), GAS, GAS/CONDENSATE, OIL or OIL/GAS. SHOWS (GAS SHOWS, OIL SHOWS or OIL/GAS SHOWS) are detected as fluorescent cut (organic extract), petroleum odour, or visual stain on cuttings or cores, or as increased gas reading on the mud-loggers gas detection equipment. Legal values for WILDCAT-CCS and APPRAISAL-CCS: WATER For development wellbores, type of produced/injected fluid. Legal values: WATER, CUTTINGS, NOT AVAILABLE, OIL, GAS/CONDENSATE, OIL/GAS, CO2, GAS, WATER/GAS, NOT APPLICABLE.	OIL/GAS
Discovery wellbore Indicator which tells if the wellbore made a new discovery. Legal values: YES, NO. Prior to press-release or other information regarding drilling results, the indicator will be “NO” as a default.	NO
1st level with HC, age Age of lithostratigraphic unit, 1st level, where hydrocarbons were encountered. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EOCENE. See also Norwegian Offshore Directorate bulletins.	LATE JURASSIC
1st level with HC, formation Name of lithostartigraphic unit, 1st level, where hydrocarbons were encountered. Shown only for released wells. Examples of legal values: BASEMENT, COOK FM, EKOFISK FM, HEIMDAL FM, SANDNES FM, SOGNEFJORD FM, TARBERT FM, BRENT GP. See also Norwegian Offshore Directorate bulletins.	SOGNEFJORD FM
2nd level with HC, age Age of lithostratigraphic unit, 2nd level, where hydrocarbons were encountered. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EOCENE.	MIDDLE JURASSIC
2nd level with HC, formation Name of lithostartigraphic unit, 2nd level, where hydrocarbons were encountered. Shown only for released wells. Examples of legal values: BASEMENT, COOK FM, EKOFISK FM, HEIMDAL FM, SANDNES FM, SOGNEFJORD FM, TARBERT FM, BRENT GP.	FENSFJORD FM
Kelly bushing elevation [m] Elevation of the rotary kelly bushing (RKB) above mean sea level.	22.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	234.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	2350.0
Final vertical depth (TVD) [m RKB] Vertical elevation from total depth to kelly bushing. Shown only for released wells. Referred to as true vertical depth (TVD).	2342.0
Maximum inclination [°] Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.	2
Bottom hole temperature [°C] Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.	94
Oldest penetrated age Age (according to Geologic Time Scale 2004 by F. M. Gradstein, et al. (2004)) of the oldest penetrated formation. May differ from age at TD for example in deviated wellbores. Examples of legal values: CRETACEOUS, EARLY CRETACEOUS, LATE JURASSIC, EARLY PERMIAN, EARLY TRIASSIC, EOCENE.	MIDDLE JURASSIC
Oldest penetrated formation Name of the oldest lithostratigraphic unit penetrated by the wellbore. Shown only for released wells. In most wellbores this is formation or group at total depth. May differ from formation or group at TD for example in wellbores drilled with high deviation or through faults. Examples of legal values: AMUNDSEN FM, BALDER FM, BASEMENT, BLODØKS FM, BRYNE FM, BURTON FM, COOK FM, DRAKE FM, DRAUPNE FM, EKOFISK FM, DUNLIN GP.	HEATHER FM
Geodetic datum Reference system for coordinates. Example of legal values: ED50.	ED50
NS degrees Geographic coordinate of the wellhead, north-south degrees.	60° 37' 29.78'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	3° 11' 16.11'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6721185.71
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	510277.82
UTM zone Universal Transverse Mercator zone. Examples of legal values: 31, 32, 33, 34.	31
NPDID wellbore Norwegian Offshore Directorate's unique id for the wellbore.	2617

Well 31/4-10 was drilled to appraise the Brage Field on the Bjørgvin Arch in the North Sea. The main objective was to confirm hydrocarbons in the Sognefjord Formation. The secondary objectives were to obtain information about reservoir properties and stratigraphic development of the Fensfjord and Krossfjord Formations.

Operations and results

Appraisal well 31/4-10 was spudded with the semi-submersible installation West Vanguard on 14 November 1995 and drilled to TD at 2342 m in Middle Jurassic sediments in the Heather Formation. The well was drilled and logged without significant problems. It was drilled with spud mud down to 1010 m and with KCl/polymer mud from 1010 m to TD.

A 21 m thick Draupne Formation was penetrated from 2004 m to 2025 m. The Sognefjord Formation was encountered at 2025 m and a total of 4.7 m net pay was calculated in the interval between 2038.0 m and 2044.9 m. The average oil saturation over this interval is estimated to 50.6 %. The average porosity is calculated to 23 %. MDT pressure measurements gave an oil-water contact at 2045 m. Low saturations of residual hydrocarbons are observed in intervals below the oil-water contact down to bottom Sognefjord Formation at 2097.5 m. No gas-oil contact could be determined from pressure measurements or logs because of the low permeability over this interval. However, a gas-oil contact at 2034.5 m was inferred from hydrocarbon shows on the cores. The Fensfjord Formation was encountered at 2167.5 m and a total of 3.2 m net pay was calculated between 2167.5 m and 2171 m. MDT pressure measurements gave an oil-water contact at 2171 m. Low saturations of residual hydrocarbons are observed in intervals below the oil-water contact down to bottom Fensfjord Formation at 2217.5 m. The Krossfjord Formation was penetrated from 2269.5 m to 2277 m and was water bearing without shows.

Eleven cores were cut in the well. Cores 1 to 6 were cut from 2005 in the Draupne Formation, through the Sognefjord Formation and into the Heather Formation at 2114.6 m. One hundred percent recovery was obtained except for core 6, where only 46% recovery was obtained. Cores 7 to 11 were cut from 2171.5 m in the Fensford Formation to 2266 m in the Heather Formation. Good recovery was obtained. The recovery on core 11 included recovery of 3.9m from core 10 during running in hole with core 11. MDT oil samples were taken at 2038.5 m in the Sognefjord Formation and at 2168.7 m in the Fensfjord Formation.

The well was permanently abandoned on 13 December 1995 as an oil appraisal well.

Testing

No drill stem test was performed.

Cuttings at the Norwegian Offshore Directorate

Cuttings at the Norwegian Offshore Directorate
Cuttings available for sampling?	YES

Cuttings at the Norwegian Offshore Directorate
Cutting sample, top depth [m]	Cutting samples, bottom depth [m]
1010.00	2350.00

Cores at the Norwegian Offshore Directorate

Cores at the Norwegian Offshore Directorate
Core sample number	Core sample - top depth	Core sample - bottom depth	Core sample depth - uom
1	2005.0	2023.8	[m ]
2	2023.8	2042.1	[m ]
3	2042.1	2059.7	[m ]
4	2059.7	2078.0	[m ]
5	2078.0	2096.6	[m ]
6	2096.6	2105.3	[m ]
7	2171.5	2186.5	[m ]
8	2189.5	2216.1	[m ]
9	2217.0	2226.7	[m ]
10	2227.0	2248.9	[m ]
11	2250.1	2266.0	[m ]

Cores at the Norwegian Offshore Directorate
Total core sample length [m]	189.4

Cores at the Norwegian Offshore Directorate
Cores available for sampling?	YES

Core photos

Core photos

2005-2010m	2010-2015m	2015-2020m	2020-2023m	2023-2028m

2028-2033m	2033-2038m	2038-2042m	2042-2047m	2047-2052m

2052-2057m	2057-2059m	2059-2064m	2064-2069m	2069-2074m

2074-2078m	2078-2083m	2083-2088m	2088-2093m	2093-2096m

2096-2101m	2101-2015m	2171-2176m	2176-2181m	2181-2186m

2186-2186m	2189-2194m	2194-2199m	2199-2204m	2204-2209m

2209-2214m	2214-2216m	2217-2222m	2222-2226m	2227-2232m

2232-2237m	2237-2242m	2242-2247m	2247-2248m	2250-2255m

2255-2260m	2260-2265m	2265-2266m

Casing and leak–off tests

Casing and leak–off tests
Casing type	Casing diam. [inch]	Casing depth [m]	Hole diam. [inch]	Hole depth [m]	Formation test type
CONDUCTOR	30	330.0	36	330.0	LOT
SURF.COND.	13 3/8	997.0	17 1/2	1010.0	LOT
INTERM.	9 5/8	1981.0	12 1/4	1990.0	LOT
OPEN HOLE		2350.0	8 1/2	2350.0	LOT

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
DLL MAFL LSS LDL CNL GR SP AMS	1930	2349
DLL MSFL LSS GR SP AMS	996	1986
MDT GR	2025	2275
MDT GR	2038	2039
MRIL GR	2010	2110
MWD - GR RES DIR	256	1990
VSP	700	2340

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
256	NORDLAND GP
742	UTSIRA FM
836	HORDALAND GP
1681	ROGALAND GP
1681	BALDER FM
1742	SELE FM
1774	LISTA FM
1944	SHETLAND GP
1991	CROMER KNOLL GP
2005	VIKING GP
2005	DRAUPNE FM
2025	SOGNEFJORD FM
2098	HEATHER FM
2168	FENSFJORD FM
2218	HEATHER FM
2270	KROSSFJORD FM
2278	HEATHER FM

Geochemical information

Geochemical information
Document name	Document format	Document size [MB]
2617_1	pdf	0.32

Documents – reported by the production licence (period for duty of secrecy expired)

Documents – reported by the production licence (period for duty of secrecy expired)
Document name	Document format	Document size [MB]
2617_31_4_10_COMPLETION_REPORT_AND_LOG	pdf	13.38

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Visc. [mPa.s]	Mud type
330	1.10		water based
1488	1.25	27.0	water based
1659	1.39	25.0	water based
1831	1.17	15.0	water based
1990	1.45	30.0	water based
2055	1.17	13.0	water based
2350	1.17	15.0	water based

31/4-10