Wellbore: 16/4-8 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.	16/4-8 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).	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
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.	SOLVEIG
Discovery Name of the discovery the wellbore is related to.	16/4-6 S Solveig
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	16/4-8
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	359
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.	Lundin Norway 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.	1510-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	BREDFORD DOLPHIN
Drilling days Number of days from wellbore entry to wellbore completion.	69
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,	19.06.2014
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.	26.08.2014
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.	26.08.2016
Plugged and abondon date Date when the P&A-operations of the wellbore was finished, as reported by the operator to the Norwegian Offshore Directorate throught DDRS (Daily Drilling Reporting System). Only applied once pr. wellhead/surface location.	26.08.2014
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.	26.08.2016
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.	TRIASSIC
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.	HEGRE GP
Kelly bushing elevation [m] Elevation of the rotary kelly bushing (RKB) above mean sea level.	25.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	100.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	2700.0
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).	2670.0
Maximum inclination [°] Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.	23.2
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° 39' 53.32'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	2° 16' 24.76'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6503106.93
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	457856.97
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.	7415

Well 16/4-8 S was drilled to appraise the Luno II discovery made by well 16/4-6 S in 2013 on the west flank of the Utsira High in the North Sea. Well 16/4-8 S targeted the Central South segment, located 4 km south of the Luno II discovery well. The objectives were to prove presence of good quality Jurassic/Triassic reservoir sandstone; to verify the petroleum potential in the Central South segment including the Luno II OWC at 1950 m MSL; and to calibrate the seismic interpretations for the Luno II sub-basin.

Operations and results

Appraisal well 16/4-8 S was spudded with the semi-submersible Bredford Dolphin on 19 June 2014 and drilled to 2700 m (2670 m TVD) in the Triassic Skagerrak Formation. The well was drilled deviated from 2100 m to avoid a prognosed fault. Mud losses occurred when drilling the interval 2391 m to TD. LCM pills were pumped to amend this. Otherwise, no significant problem was encountered in the operations. The well was drilled with spud mud down to 610 m and with Aquadril mud from 610 m to TD.

Top reservoir Hegre Group, was encountered at 1934 m (1934 m TVD). No Jurassic sediments were present. The Skagerrak Formation held a total oil column of about 30 m, of which about 15 m had very good reservoir properties. The oil is saturated with a thin gas column on top. Between ca 1970 m and ca 1980 m the reservoir was mainly water bearing, and then a separate zone with biodegraded oil and water was sampled from 1980 to 1987. No clear OWC could be established from the well data. The reservoir rocks, including the water zone, consist of 500-metre thick sandstones over a 200-metre thickness of conglomerate rock. Pressure data shows there is no pressure communication between 16/4-8 S and the 16/4-6 S discovery well.

The first oil show appeared in sidewall cores in Shetland Group limestone from 1928 m, six meter above top reservoir. Variable but generally good oil shows were described throughout the oil-bearing reservoir and down to 2030 m. Local weak oil shows were described in the Hegre Group below 2030 m down to 2382 m.

Seventy-three meter core was recovered in seven consecutive cores in the interval 1935 to 2009 m (98.7% total recovery). MDT fluid samples were taken at 1934.5 m (condensate), 1942.3 m (oil), 1942.5 m (oil), 1945.5 m (oil), 1955.7 m (oil), 1962 m (oil), 1962.8 m (oil), 1967 m (oil), 1975 m (water), 1980 m (slightly biodegraded oil/water/gas), 1987 m (water and traces of mildly biodegraded oil), 2024 m (water), and 2508.2 m (water).

The well was permanently abandoned on 26 August 2014 as an oil and gas appraisal well.

Testing

One production test was performed in the well 16/4-8 S. The interval 1940 to 1958 m was perforated and produced with a final flow rate of 63 Sm3 oil and 12030 Sm3 gas /day through a 28/64" fixed choke with a wellhead pressure of 17 bar. A GOR of 192 Sm3/Sm3 was measured at separator conditions of 44.2 °C and 8.7 bar. The on-site measured oil density at 15 °C was 0.89 g/cc and the gas gravity was 0.91(air = 1). The H2S and CO2 contents were less than 0.1 ppm and 0.2 % respectively. The maximum temperature recorded at gauge depth 1919.37 was 81°C, but due to significant Joule-Thompson effects the recorded temperatures varied widely, and the true formation temperature could not reliably be established.

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]
620.00	2700.00

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	1935.0	1948.1	[m ]
2	1948.1	1960.0	[m ]
3	1960.4	1970.9	[m ]
4	1970.9	1985.8	[m ]
5	1986.0	1997.0	[m ]
6	1996.0	2002.2	[m ]
7	2002.2	2008.6	[m ]

Cores at the Norwegian Offshore Directorate
Total core sample length [m]	74.0

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]	LOT/FIT mud eqv. [g/cm3]	Formation test type
CONDUCTOR	30	203.0	36	203.0	0.00
SURF.COND.	20	602.0	26	610.0	1.81	LOT
PILOT HOLE		610.0	9 7/8	610.0	0.00
OPEN HOLE		615.0	17 1/2	615.0	0.00
PROD.	9 5/8	1910.0	12 1/4	1918.0	1.50	FIT
OPEN HOLE		2700.0	8 1/2	2700.0	0.00

Drill stem tests (DST)

Drill stem tests (DST)
Test number	From depth MD [m]	To depth MD [m]	Choke size [mm]
1.0	1940	1958	11.1

Drill stem tests (DST)
Test number	Final shut-in pressure [MPa]	Final flow pressure [MPa]	Bottom hole pressure [MPa]	Downhole temperature [°C]
1.0				44

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	63	12030			192

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
ADT MDT	1934	2383
ADT MDT	1934	2673
ADT MDT	1962	2508
DSL CN ZDL ORIT XMAC RTEX MLL	1859	2704
DSL CN ZDL ORIT XMAC RTEX MLL	1865	2409
FLEX MREX	1917	2403
FLEX MREX	2337	2707
GEOWAVES	354	2389
GEOWAVES	829	2689
MAXCOR	1928	2365
MDT	1934	2024
MSCT	1928	2366
MWD - GR RES DEN NEU SON DIR PWD	573	2697
MWD - GR RES SON DIR PWD	125	607
STAR-HD ORIT UXPL	1875	2398
STAR-HD ORIT UXPL	2328	2696
XL-ROCK	2029	2682

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
125	NORDLAND GP
760	UTSIRA FM
1027	HORDALAND GP
1042	SKADE FM
1209	HORDALAND GP
1747	ROGALAND GP
1747	BALDER FM
1750	SELE FM
1800	LISTA FM
1897	VÅLE FM
1907	SHETLAND GP
1907	EKOFISK FM
1928	TOR FM
1932	HOD FM
1933	CROMER KNOLL GP
1934	HEGRE GP
1934	SKAGERRAK FM

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Visc. [mPa.s]	Mud type
125	1.03	111.0	Water Based
610	1.03	111.0	Water Based
1174	1.35	21.0	Water Based
1657	1.40	22.0	Water Based
1913	1.20	19.0	Water Based
1918	1.40	22.0	Water Based
2009	1.20	19.0	Water Based
2407	1.20	21.0	Water Based
2700	1.10	30.0	Water Based

16/4-8 S