Wellbore: 2/8-10 - 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.	2/8-10
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.	VALHALL
Discovery Name of the discovery the wellbore is related to.	2/8-6 Valhall
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	2/8-10
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	006
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.	Amoco Norway Oil Company
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.	157-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	SEDCO 135 G
Drilling days Number of days from wellbore entry to wellbore completion.	61
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,	30.06.1976
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.	29.08.1976
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.	29.08.1978
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.	16.10.2012
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
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 CRETACEOUS
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.	TOR 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.	LATE CRETACEOUS
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.	HOD FM
Kelly bushing elevation [m] Elevation of the rotary kelly bushing (RKB) above mean sea level.	33.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	69.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	2683.0
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).	2682.0
Bottom hole temperature [°C] Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.	69
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.	EARLY CRETACEOUS
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.	RØDBY FM
Geodetic datum Reference system for coordinates. Example of legal values: ED50.	ED50
NS degrees Geographic coordinate of the wellhead, north-south degrees.	56° 15' 53.32'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	3° 24' 58.81'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6235769.11
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	525789.33
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.	280

Well 2/8-10 was drilled as a field delineation well intended to help establish the commerciality of the Valhall Field, which was discovered by well 2/8-6 and confirmed by wells 2/8-8 and 2/8-9. The main purpose of 2/8-10 was to evaluate the Tor and Upper Hod reservoirs on the south eastern flank of the Valhall structure.

Operations and results

Appraisal well 2/8-10 was spudded with the semi-submersible installation Sedco 135 G on 30 June 1976 and drilled to TD at 2682 m in the Early Cretaceous Rødby Formation. The well was drilled with seawater and bentonite down to 375 m, and with seawater/lime/Drispac mud from 375 m to TD.

The objective reservoirs, developed in chalk of the Tor and Hod Formations, were encountered at depths of 2476.5 m and 2516 m respectively. A gross pay interval of 77 m was encountered. The Tor Formation was approximately 38 m thick with an oil saturation of 95% and was tested at rates of up to 1000 Sm3/day. The upper Hod reservoir, approximately 38 m thick, was found to be hydrocarbon bearing, although oil saturations were low, averaging 25% and the reservoir was tested at up to 67 Sm3/day. As anticipated, the lower Hod reservoir was wet.

Only insignificant, although fairly consistent, oil shows were encountered in the Hordaland and Rogaland Groups. Excellent shows were recorded in the Tor Formation. The quality of the shows decreased gradually through the upper part of the Hod Formation and only minor oil shows were encountered below 2570 m.

Four conventional cores were cut in the interval 2477.1 m to 2508.5 m with an overall recovery of 70%. No wire line fluid samples were taken.

The well was permanently abandoned on 29 August 1076 as an oil appraisal well.

Testing

Three drill stem tests were conducted. DST1 and DST3 were conducted after fracturing the reservoirs using the Kiel water-frac process.

DST1 was conducted over the interval 2535.9 to 2546.6 m in the Hod Formation. It produced 57 Sm3 oil/day with a GOR of 309 Sm3/Sm. Oil gravity was 31.9 deg API and gas gravity was 0.674 (air = 1).
DST2 was conducted over the interval 2493.2 to 2508.5 m in the lower Tor Formation. It produced 566 Sm3 oil/day with a GOR of 138 Sm3/Sm. Oil gravity was 36.5 deg API and gas gravity was 0.653 (air = 1).
DST3 was conducted over the interval 2479.5 to 2485.6 m in the upper Tor Formation. It produced 876 Sm3 oil/day with a GOR of 167 Sm3/Sm3 through a 5/8" (15.9 mm) choke. Oil gravity was 37.5 deg API and gas gravity was 0.660 (air = 1). Sperry Sun reported a bottom hole temperature of 116.7 deg C from this test.

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]
182.88	2682.24

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
2	8140.0	8170.0	[ft ]
3	8173.0	8188.0	[ft ]
4	8197.0	8224.0	[ft ]

Cores at the Norwegian Offshore Directorate
Total core sample length [m]	21.9

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

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	174.0	36	174.0	LOT
SURF.COND.	20	368.0	26	375.0	LOT
INTERM.	13 3/8	1280.0	17 1/2	1286.0	LOT
INTERM.	9 5/8	2602.0	12 1/4	2682.0	LOT

Drill stem tests (DST)

Drill stem tests (DST)
Test number	From depth MD [m]	To depth MD [m]	Choke size [mm]
1.0	2536	2547	3.2
2.0	2493	2509	9.5
3.0	2480	2486	15.9

Drill stem tests (DST)
Test number	Final shut-in pressure [MPa]	Final flow pressure [MPa]	Bottom hole pressure [MPa]	Downhole temperature [°C]
1.0
2.0
3.0

Drill stem tests (DST)
Test number	Oil [Sm3/day]	Gas [Sm3/day]	Oil density [g/cm3]	Gas grav. rel.air	GOR [m3/m3]
1.0	49	6760	0.840	0.674	775
2.0	552	78155	0.840	0.653	793
3.0	1017	165937	0.840	0.660	910

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
CBL GR TT	100	356
CBL TT	2285	2495
CBL VDL CCL	2285	2489
CBL VDL GR TT	1185	2556
CNFD GR CAL	2315	2621
DIP	2315	2621
DLL MSFL GR SP CAL	2315	2621
ISF SON RIL SP GR	368	1287
ISF SON SP GR	1280	2619
ISF SON SP GR	2425	2680
SON VDL GR	2315	2620
TEMP	2350	2560
TEMP	2350	2560
TEMP	2350	2650
TEMP	2350	2621
TEMP	2350	2621
TEMP	2350	2621

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
102	NORDLAND GP
1498	HORDALAND GP
2441	ROGALAND GP
2441	BALDER FM
2452	SELE FM
2462	LISTA FM
2477	SHETLAND GP
2477	TOR FM
2516	HOD FM
2636	BLODØKS FM
2639	HIDRA FM
2653	CROMER KNOLL GP
2653	RØDBY 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]
280_2_8_10_Completionlog	pdf	2.20
280_2_8_10_Completion_report	pdf	21.25

Documents – older Norwegian Offshore Directorate WDSS reports and other related documents

Documents – older Norwegian Offshore Directorate WDSS reports and other related documents
Document name	Document format	Document size [MB]
280_01_WDSS_General_Information	pdf	0.28

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Mud type
0	1.86	water-based
159	1.04	spud-mud
375	1.25	spud-mud
1286	1.24	spud-mud
1660	1.79	water-based
2477	1.89	water-based

2/8-10