Wellbore: 15/12-12 - 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.	15/12-12
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.	RE-CLASS TO DEV
Press release	link
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.	REV
Discovery Name of the discovery the wellbore is related to.	15/12-12 Rev
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	15/12-12
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	038
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.	Saga Petroleum ASA
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.	938-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	SCARABEO 6
Drilling days Number of days from wellbore entry to wellbore completion.	47
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,	25.12.2000
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.	09.02.2001
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.	09.02.2003
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.	19.10.2006
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
Reclassified to wellbore	15/12-C-1 H
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.	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.	INTRA HEATHER FM SS
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.	TRIASSIC
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.	SKAGERRAK FM
Kelly bushing elevation [m] Elevation of the rotary kelly bushing (RKB) above mean sea level.	26.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	87.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	3085.0
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).	3056.0
Maximum inclination [°] Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.	26
Bottom hole temperature [°C] Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.	126
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.	TRIASSIC
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.	SKAGERRAK FM
Geodetic datum Reference system for coordinates. Example of legal values: ED50.	ED50
NS degrees Geographic coordinate of the wellhead, north-south degrees.	58° 1' 40.68'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	1° 55' 28.34'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6432475.78
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	436478.40
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.	3391

The objective for well 15/12-12 was to test the hydrocarbon potential of the Rev structure in PL 038 approximately 5 km south-east of the Varg Field (Varg A Platform). The target level was Oxfordian Intra Heather Sands of the Viking Group.

Operations and results

Well 15/12-12 was spudded with the semi-submersible installation Scarabeo 6 on 25 December 2000 and drilled to TD at 3085 m in the Triassic Skagerrak Formation. At ca 2700 m the well starts to build angle up to a deviation of ca 25 deg at ca 2830 m. This deviation is kept down to TD where it leads to a difference between measured and vertical depth of ca 30 m. The well was drilled with seawater and hi-vis pills through to the base of the 17 1/2" section at 1384 m and with Glydrill KCL Polymer from 1384 m to TD.

A total of 121 m (2856 - 2977 m) gross Late Jurassic, Intra Heather reservoir sequence was penetrated in well 15/12-12 on the Rev Structure. The reservoir is interpreted as shallow marine sand bodies and is dated Oxfordian of age. On top of the reservoir lie 6 m sand dated Earliest Kimmeridgian of age. This sand was not considered as part of the net reservoir. The massive Intra Heather sands had very good reservoir quality. The cored interval of the reservoir had good hydrocarbon shows. Pressure data showed a clear gas gradient with a distinct GOC at 2954 m (2912 m TVD MSL) and an oil gradient down to base of reservoir (Top Triassic) at 2977 m (2932.5 m TVD MSL). MDT samples of the oil leg indicated an oil-down-to (ODT) situation. The pressure data also showed approximately 40 bars of depletion, caused by the production on the Varg Field (Southern Segment).

The interval between 2864 - 3000 m was cored in six cores, nearly the complete reservoir section and the upper part of Triassic. MDT fluid samples were taken throughout the reservoir at 2867.5 m, 2895 m, 2961 m, 2964.2 m, and 2972.5 m. Samples from the two deepest levels recovered variable proportions of water and oil, reflecting the lack of a clear oil-water contact (OWC) in the reservoir. This is interpreted as an effect of the pressure depletion due to the production on Varg. Apart from the sampled water, which was heavily mud contaminated, sampled fluids were considered representative for the reservoir.

The well was permanently abandoned on 9 February 2001 as an oil and gas discovery.

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]
1440.00	3085.00

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	2864.0	2892.0	[m ]
2	2892.0	2920.0	[m ]
3	2920.0	2948.0	[m ]
4	2948.0	2974.7	[m ]
5	2976.0	2984.2	[m ]
6	2986.0	2997.7	[m ]

Cores at the Norwegian Offshore Directorate
Total core sample length [m]	130.6

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

Core photos

Core photos

2864-2869m	2869-2874m	2874-2879m	2879-2884m	2884-2889m

2889-2894m	2894-2899m	2899-2904m	2904-2909m	2909-2914m

2914-2919m	2919-2924m	2924-2929m	2929-2934m	2934-2939m

2939-2944m	2944-2949m	2949-2954m	2954-2959m	2959-2964m

2964-2969m	2969-2974m	2974-2980m	2980-2984m	2986-2991m

2991-2996m	2996-2998m

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
CONDUCTOR	30	185.0	36	185.0	0.00	LOT
SURF.COND.	20	599.0	26	605.0	0.00	LOT
INTERM.	13 3/8	1377.0	17 1/2	1384.0	2.18	LOT
INTERM.	9 5/8	2829.0	12 1/4	2836.0	0.00	LOT
OPEN HOLE		3085.0	8 1/2	3035.0	0.00	LOT

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
APS VSP CCL	2460	3040
CMR ECS	2820	2983
DP MDT	2964	2972
DSI ECS HNGS	2200	2829
FMI DSI CMR200	2182	2362
MDT	2859	2937
MDT	2895	3040
MWD ADN RAB	2827	3084
MWD CDR	113	1375
MWD CDR CDN RAB	1366	2823

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
113	NORDLAND GP
1065	UTSIRA FM
1245	HORDALAND GP
2238	ROGALAND GP
2238	BALDER FM
2252	SELE FM
2312	LISTA FM
2420	VÅLE FM
2445	SHETLAND GP
2445	EKOFISK FM
2450	TOR FM
2558	HOD FM
2651	BLODØKS FM
2675	HIDRA FM
2711	CROMER KNOLL GP
2711	RØDBY FM
2733	SOLA FM
2774	RØDBY FM
2793	VIKING GP
2793	DRAUPNE FM
2861	INTRA HEATHER FM SS
2977	HEGRE GP
2977	SKAGERRAK FM

Composite logs

Composite logs
Document name	Document format	Document size [MB]
3391_15_12_12	pdf	0.42

Geochemical information

Geochemical information
Document name	Document format	Document size [MB]
3391_1	pdf	2.20

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]
3391_15_12_12_COMPLETION_LOG	.pdf	6.86
3391_15_12_12_COMPLETION_REPORT	.pdf	3.69

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Visc. [mPa.s]	Mud type
185	1.09		WATER BASED
456	1.09		WATER BASED
970	1.05		WATER BASED
2110	1.35	20.0	WATER BASED
2836	1.39	25.0	WATER BASED
2841	1.35	23.0	WATER BASED
3085	1.36	20.0	WATER BASED
3088	1.36	19.0	WATER BASED

15/12-12