Wellbore: 16.02.1994 - 15/9-20 S - 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.	15/9-20 S
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
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.	SLEIPNER ØST
Discovery Name of the discovery the wellbore is related to.	15/9-9 Sleipner Øst
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	15/9-20
Seismic location Position of spud location on seismic survey lines. SP: shotpoint.	ST 8215 R-3D
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	046
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.	Den norske stats oljeselskap a.s
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.	787-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	SLEIPNER A
Drilling days Number of days from wellbore entry to wellbore completion.	33
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,	16.02.1994
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.	20.03.1994
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.	20.03.1996
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.	18.01.2007
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	15/9-A-22
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.	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.	PALEOCENE
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.	HEIMDAL 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.	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.	78.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	82.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	3626.0
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).	2801.0
Maximum inclination [°] Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.	53.7
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.	SMITH BANK FM
Geodetic datum Reference system for coordinates. Example of legal values: ED50.	ED50
NS degrees Geographic coordinate of the wellhead, north-south degrees.	58° 22' 1.89'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	1° 54' 31.98'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6470257.29
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	436165.07
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.	2319

Wildcat well 15/9-20 S was drilled from the Sleipner A platform on the Sleipner øst Field. It started off as development well 15/9-A-22, which was designed to provide gas production from the Heimdal reservoir in the central part of the Sleipner Øst Field, and to contribute with geological and reservoir technical data for optimal reservoir management in this area. Due to unexpected geology in the deeper part of the well the Cretaceous and below was reclassified to exploration well 15/9-20 S.

Operations and results

Well 15/9-20 S was spudded from the fixed installation Sleipner A on 16 February 1994 and drilled deviated to TD at 3624 m in the Triassic Smith Bank Formation. No significant problems were reported from the operations. The well was drilled with seawater/PAC mud from below 26" conductor to 506 m, with KCl/PHPA/PAC mud from 506 m to 1735 m, with KCl/PHPA/PAC/Glycol mud from 1735 m to 2928 m, and with ester mud from 2928 m to TD. No shallow gas was encountered.

The well penetrated the Heimdal Formation target at 2931 m (2279.6 m TVD MSL), 11.6 m TVD deeper than prognosis. The Heimdal Formation was 104 m thick (71.2 m TVD) and proved to be gas filled as expected. Under the Heimdal Formation the well drilled 204 m Late Cretaceous limestone overlying 8 m Blodøks Formation. At 3247 m (2490.2 m TVD MSL) the well drilled unexpected into Jurassic/Triassic sandy sediments, which proved to have a 30 - 50 m TVD hydrocarbon leg.

Five conventional cores were cut from 2940 - 3043 m in the Heimdal and into the top of the Tor Formation. A sixth core was cut from 3216 - 3244 m, from base Hod Formation and into the Blodøks Formation. One RFT segregated sample was taken at 3272.6 m in the Skagerrak Formation.

Well bore 15/9-20 S was plugged back and permanently abandoned on 1 June 1994 as a gas discovery.

Testing

The well was perforated on wire line over the interval 3229 - 3238 m in the base of the Hod Formation and stimulated with acid, but the result was negative and the interval was plugged. Two drill stem tests were performed in the Heimdal Formation sandstone. DST 1 tested the interval 2942 - 2956 m and DST 2 tested the interval 2933 - 2942 m.

Core photos

Core photos

2940-2945m	2945-2950m	2950-2954m	2954-2959m	2959-2964m

2964-2969m	2969-2974m	2974-2977m	2977-2982m	2982-2987m

2987-2992m	2992-2997m	2997-3002m	3002-3006m	3006-3010m

3010-3015m	3015-3015m	3015-3020m	3020-3025m	3025-3030m

3030-3035m	3035-3040m	3040-3045m	3216-3221m	3221-3226m

3226-3231m	3231-3236m	3236-3241m	3241-3244m

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
160	NORDLAND GP
911	UTSIRA FM
1131	HORDALAND GP
1279	SKADE FM
1308	NO FORMAL NAME
2645	ROGALAND GP
2645	BALDER FM
2713	SELE FM
2820	LISTA FM
2931	HEIMDAL FM
3035	SHETLAND GP
3035	TOR FM
3195	HOD FM
3239	BLODØKS FM
3247	VIKING GP
3247	DRAUPNE FM
3249	HEATHER FM
3259	NO GROUP DEFINED
3259	SKAGERRAK FM
3503	SMITH BANK FM

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]
2319_15_9_20_S_COMPLETION_LOG	pdf	1.18

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
DIL BHC GR	2922	3627
LDL BHC GR	1729	2917
LDL CNL GR	2922	3627
MWD - DPR GR	506	2928
RFT HP GR	2942	3577
VSP	1788	3588

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	26	283.0	30	285.0	0.00	LOT
SURF.COND.	18 5/8	501.0	20	504.0	0.00	LOT
INTERM.	13 3/8	1729.0	17 1/2	1731.0	1.65	LOT
INTERM.	9 5/8	2922.0	12 1/4	2922.0	1.78	LOT
LINER	7	3624.0	8 1/2	3626.0	1.92	LOT

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Visc. [mPa.s]	Mud type
506	1.11	26.0	WATER BASED
1073	1.30	25.0	WATER BASED
1541	1.35	29.0	WATER BASED
1735	1.35	32.0	WATER BASED
2255	1.64	41.0	WATER BASED
2653	1.64	51.0	WATER BASED
2921	1.20	20.0	OIL BASED
2928	1.64	44.0	WATER BASED
2940	1.20	20.0	OIL BASED
3015	1.23	24.0	OIL BASED
3206	1.23	25.0	OIL BASED
3244	1.24	25.0	OIL BASED
3307	1.33	30.0	OIL BASED
3626	1.28	24.0	OIL BASED

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]
2319_Formation_pressure_(Formasjonstrykk)	pdf	0.23

15/9-20 S