Wellbore: 33/12-8 A - 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.	33/12-8 A
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).	WILDCAT
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
Press release	link to press release
Factmaps in new window	link to map
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.	GULLFAKS SØR
Discovery Name of the discovery the wellbore is related to.	33/12-8 A Skinfaks
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	33/12-8
Seismic location Position of spud location on seismic survey lines. SP: shotpoint.
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	152
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.	Statoil ASA (old)
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.	1037-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	BORGLAND DOLPHIN
Drilling days Number of days from wellbore entry to wellbore completion.	21
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,	26.04.2002
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.	16.05.2002
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.	16.05.2004
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.	18.05.2004
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.	WILDCAT
Reentry Status whether the wellbore has been re-entered (YES) or not (NO). Re-entered wellbores are not included in the count when wellbores are presented in statistical overviews.	NO
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.	YES
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.	MIDDLE 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.	TARBERT FM
Kelly bushing elevation [m] Elevation of the rotary kelly bushing (RKB) above mean sea level.	31.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	137.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	5098.0
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).	3399.0
Bottom hole temperature [°C] Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.	119
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.	RANNOCH FM
Geodetic datum Reference system for coordinates. Example of legal values: ED50.	ED50
NS degrees Geographic coordinate of the wellhead, north-south degrees.	61° 4' 38.34'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	1° 57' 56.2'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6772000.95
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	444189.05
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.	4532

Well 33/12-8 A is a sidetrack from well 33/12-8 S in the Tampen Spur area. It is situated on a westerly rotated fault block on the southern part of the Beta Ridge. The main objective of well 33/12-8 A was to investigate the hydrocarbon potential in the Middle Jurassic Brent Group in the "Ole" prospect (Skinfaks segment N2), as a result of the positive hydrocarbon discovery in the Skinfaks N3 segment. The secondary objective was to identify the hydrocarbon contact in the Tarbert Formation.

Operations

The wildcat well 33/12-8 A was side-tracked from the 13 3/8" casing at 2066 m in well 33/12-8 S on 26 April 2002 with the semi-submersible installation Borgland Dolphin and drilled to TD at 5098 m /3399.5 m TVD RKB in the Rannoch Formation. The well was drilled with Versavert OBM from kick-off to TD. For well history above sidetrack, see well 33/12-8 S. Technical difficulties were experienced during the sidetrack of 33/12-8 A. Because of problems with attaining the necessary azimuth turn to reach target T1, it was necessary to pull out twice in the beginning of the well to get the desired well path.

Both geology and oil-water contact came approximately as prognosed in segment N2. Gas was proven in the uppermost part of the reservoir, while the lower part is oil filled. The sediment layers in segment N2 came in 30 meters deeper than prognosed.

No cores were cut. Twelve fluid samples were collected in well 33/12-8 A, in two reservoirs of the Tarbert Formation. Six of the samples were collected in the N3 reservoir. Oil was found in the samples collected from the depths 2954 and 2922 m. Gas/condensate was found at depths 2906 and 2868 m. The oil samples collected from depths 2922 and 2954 suffered different technical problems and one sample from 2922 contained 12 percent contamination. The gas/condensate samples contained 28 to 40 percent contamination. The last six samples were collected in the N2 reservoir. Water was found in the sample from depth 4606 m, oil was found in the samples collected from depth 4565 m, and gas/condensate was found in the samples from depths 4136.4 and 4033 m. The oil samples collected from depths 4565 m contained 15 percent contamination. The gas/condensate samples contained 3 to 19 percent contamination. The water sample was not registered with any contamination.

The pore pressure at the top of the Brent prospect in segment N2 is calculated to be 411 Bars (2825 m TVD MSL), corresponding to 1,48 g/cm3 EMW. Well 33/12-8 A was suspended on 16 May 2002 as an oil and gas discovery and a possible future producer.

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]
2090.00	5095.00

Oil samples at the Norwegian Offshore Directorate

Oil samples at the Norwegian Offshore Directorate
Test type	Bottle number	Top depth MD [m]	Bottom depth MD [m]	Fluid type	Test time	Samples available
DST		0.00	0.00	CONDENSATE		YES

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
168	NORDLAND GP
840	UTSIRA FM
931	HORDALAND GP
1807	ROGALAND GP
1807	BALDER FM
1885	LISTA FM
2030	SHETLAND GP
2649	VIKING GP
2649	HEATHER FM
2866	BRENT GP
2866	TARBERT FM
3127	NESS FM
3182	TARBERT FM
3630	VIKING GP
3630	HEATHER FM
3902	BRENT GP
3902	TARBERT FM
4167	VIKING GP
4167	HEATHER FM
4554	BRENT GP
4554	TARBERT FM
4770	NESS FM
5041	ETIVE FM
5075	RANNOCH FM

Composite logs

Composite logs
Document name	Document format	Document size [MB]
4532	pdf	0.57

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]
4532_33_12_8_A_COMPLETION_LOG	.pdf	2.27
4532_33_12_8_A_COMPLETION_REPORT	.pdf	0.60

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
MDT TLC	2850	4606
MDT TLC	3125	5078
MWD - LWD CDR	2100	2283
MWD - LWD CDR	2283	2411
MWD - LWD CDR	2814	5098
MWD - LWD CDR BHI	2411	2814
PEX AITH GR	2778	3801
PEX AITH GR	3700	5078
PEX AITH GR MDT	2066	3170

Casing and leak–off tests

Casing and leak–off tests
Casing type	Casing diam. [inch]	Casing depth [m]	Hole diam. [inch]	Hole depth [m]	LOT/FIT mud eqv. [g/cm3]	Formation test type
INTERM.	9 5/8	5098.0	12 1/4	5098.0	0.00	LOT

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Visc. [mPa.s]	Mud type
2449	1.64	42.0	VERSAVERT
2775	1.64	40.0	VERSAVERT
2832	1.64	44.0	VERSAVERT
3962	1.64	56.0	VERSAVERT
4297	1.64	49.0	VERSAVERT
4297	1.64	49.0	VERSAVERT

Pressure plots

Pressure plots
The pore pressure data is sourced from well logs if no other source is specified. In some wells where pore pressure logs do not exist, information from Drill stem tests and kicks have been used. The data has been reported to the NPD, and further processed and quality controlled by IHS Markit.

Pressure plots
Document name	Document format	Document size [MB]
4532_Formation_pressure_(Formasjonstrykk)	pdf	0.22

33/12-8 A