Wellbore: 10.08.1994 - 25/11-18 - 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.	25/11-18
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
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.	GRANE
Discovery Name of the discovery the wellbore is related to.	25/11-15 Grane
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	25/11-18
Seismic location Position of spud location on seismic survey lines. SP: shotpoint.	NH 9301-INLINE 604&CROSSLINE 1413
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	169
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.	Norsk Hydro Produksjon 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.	794-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	WEST VANGUARD
Drilling days Number of days from wellbore entry to wellbore completion.	76
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,	10.08.1994
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.	24.10.1994
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.	24.10.1996
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.	29.08.2003
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
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
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.	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
Kelly bushing elevation [m] Elevation of the rotary kelly bushing (RKB) above mean sea level.	22.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	128.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	1875.0
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).	1874.0
Maximum inclination [°] Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.	9.3
Bottom hole temperature [°C] Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.	83
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.	LATE 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.	HOD FM
Geodetic datum Reference system for coordinates. Example of legal values: ED50.	ED50
NS degrees Geographic coordinate of the wellhead, north-south degrees.	59° 9' 8.45'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	2° 28' 28.79'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6557285.94
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	469950.36
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.	2358

Well 25/11 -18 was drilled to appraise the 25/11-15 Grane discovery drilled in 1991. The primary objectives of 25/11-18 were to confirm beyond reasonable doubt recoverable oil reserves greater than 30 million Sm3 in the Heimdal Formation in the Grane Discovery prior to initiating PDO activities; to obtain an Utsira formation water sample and water production rates in order to design the water injection system for the Grane Field; to confirm top and base reservoir, reservoir development, continuity, and quality of Heimdal sand in order to reduce the uncertainties in the resource estimates; to obtain velocity information as input to depth conversion model for the Grane Field; and to test coiled tubing drilling/coring technology as concept for future cost savings.

Operations and results

Appraisal well 25/11-18 was spudded with the semi-submersible installation "West Vanguard" on 10 August 1994 and drill to a total depth of 1875 m in the Late Cretaceous limestones of the Hod Formation. Due to technical problems it was not possible to do wire line logging at TD of the original well. The well was technically sidetracked (25/11-18 T2) with kick-off at 1390 m. The well was drilled with spud mud through the 36" and 24" sections down to 563 m, with polymer mud through the 17 1/2" section to 1183 m, with "ANCO 2000" mud from 1183 through the 8 1/2" section and into the slim 4 1/8" section down to 1690 m where the hole was displaced to "AQUACOL" mud.& Drilling of the 4 1/8" section continued with "AQUACOL" mud down to TD at 1860 m. The technical sidetrack was drilled as a 6" hole to final TD at 1875 m using KCl / Polymer mud. Coiled tubing drilling and coring and slim hole logging was proven possible from an offshore floater with acceptable quality on geological information. Operations, however, were hampered by problems related to junk and hole instability due to low mud weights.

A thin, 1 m thick oil bearing sand was encountered near the top of the Balder Formation at 1675 m. Heimdal Sand was penetrated at 1741.5 m in well 25/11-18 T2. A gross reservoir thickness of 55.5m was defined, giving a net pay of 47.1m. Good oil shows were seen on cores in the interval 1720 m to 1794 m in the original well and at 1606 m (SWC) and in the interval 1720 m to 1743 m in the sidetrack. The pressure data from the Heimdal Formation indicates a possible 1.2 bar pressure difference to well 25/11-15. Oil-water contact in well 25/11-18 was at 1765.2 m TVD, 2 m deeper than in well 25/11-15. Oil composition in 25/11-18 appears geochemically identical to oil in 25/11-15. No free gas cap was found in the sandstones. The well proved the Grane Field reserves to be greater than 30 million Sm3, confirming the reservoir and seismic models. Velocity information from the well indicated local / extended pull up of top and base of reservoir.

The Utsira water sample was of excellent quality. Dynamic test data of good quality were obtained. A total of 16 cores were cut in the interval from 1690 m to 1805 m in the Sele, Lista, and Heimdal Formations. The twelve first cores were cut in the 4 1/8" section of the original hole with recovery from 0 % to 93.3%. The last four cores were cut in the 6" technical sidetrack in the interval 1712 m to 1743.7 m with 75% to 96% recovery. A SRFT wire line fluid sample was recovered from 1755 m in the Heimdal Formation. The well was permanently abandoned as an oil appraisal well on 24. October 1993.

Testing

A DST was performed over the interval 815 m to 865 m in the Utsira Formation. The test produced at maximum rate 3934 Sm3 water and no gas pr day, at sampling rate 1045 Sm3 water and 1081 Sm3 gas pr day. No sand was produced at either rate. The gas gravity was 0.63 (air = 1).

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]
570.00	1875.00

Core photos

Core photos

1690-1691m	1690-1691m	1699-1700m	1699-1700m	1728-1729m

1720-1722m	1720-1722m	1720-1722m	1720-1722m	1747-1750m

1747-1750m	1747-1750m	1747-1750m	1747-1750m	1751-1756m

1751-1756m	1751-1756m	1751-1756m	1751-1756m	1751-1756m

1751-1756m	1751-1756m	1751-1756m	1769-1772m	1769-1172m

1769-1772m	1769-1772m	1769-1772m	1769-1772m	1778-1782m

1778-1782m	1778-1782m	1778-1782m	1778-1782m	1778-1782m

1787-1794m	1787-1794m	1787-1794m	1787-1794m	1787-1749m

1787-1794m	1787-1794m	1787-1794m	1787-1794m	1787-1794m

1787-1794m	1787-1794m	1787-1794m	1796-1804m	1796-1804m

1796-1804m	1796-1804m	1796-1804m	1796-1804m	1796-1804m

1796-1804m	1796-1804m	1796-1804m	1796-1804m	1796-1804m

1796-1804m	1796-1804m	1712-1719m	1712-1719m	1712-1719m

1712-1719m	1712-1719m	1712-1719m	1712-1719m	1712-1719m

1712-1719m	1712-1719m	1712-1719m	1712-1719m	1712-1719m

17120-1726m	1720-1726m	1720-1726m	1720-1726m	1720-1726m

1720-1726m	1720-1726m	1720-1726m	1720-1726m	1720-1719m

1728-1732m	1728-1732m	1728-1732m	1728-1732m	1728-1732m

1728-1732m	1728-1732m	1728-1732m	1733-1742m	1733-1742m

1733-1742m	1733-1742m	1733-1742m	1733-1742m	1733-1742m

1733-1742m	1733-1742m	1733-1742m	1733-1742m	1733-1742m

1733-1742m	1733-1742m	1733-1742m	1733-1742m	1733-1742m

Palynological slides at the Norwegian Offshore Directorate

Palynological slides at the Norwegian Offshore Directorate
Sample depth	Depth unit	Sample type	Laboratory
1720.0	[m]	C	0D
1728.0	[m]	C	OD
1728.1	[m]	C	0D
1740.1	[m]	C	0D
1747.0	[m]	C	0D
1751.1	[m]	C	0D
1778.0	[m]	C	0D
1796.0	[m]	C	0D
1799.0	[m]	C	0D
1804.0	[m]	C	0D
1805.0	[m]	DC	0D
1810.0	[m]	DC	0D
1820.0	[m]	DC	0D

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	WATER	14.10.1994 - 00:00	YES

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
150	NORDLAND GP
664	UTSIRA FM
744	NO FORMAL NAME
811	HORDALAND GP
811	SKADE FM
1048	UNDIFFERENTIATED
1108	NO FORMAL NAME
1114	UNDIFFERENTIATED
1437	GRID FM
1464	NO FORMAL NAME
1674	ROGALAND GP
1674	BALDER FM
1690	SELE FM
1695	LISTA FM
1742	HEIMDAL FM
1798	LISTA FM
1807	VÅLE FM
1834	SHETLAND GP
1834	EKOFISK FM
1850	TOR FM
1865	HOD FM

Composite logs

Composite logs
Document name	Document format	Document size [MB]
2358	pdf	0.25

Geochemical information

Geochemical information
Document name	Document format	Document size [MB]
2358_1	pdf	1.91
2358_10	pdf	1.90
2358_11	pdf	1.93
2358_12	pdf	1.42
2358_2	pdf	1.20
2358_3	pdf	1.78
2358_4	pdf	1.82
2358_5	pdf	1.78
2358_6	pdf	1.79
2358_7	pdf	1.84
2358_8	pdf	1.76
2358_9	pdf	1.59

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]
2358_25_1_18_COMPLETION_REPORT_AND_LOG	pdf	49.53

Drill stem tests (DST)

Drill stem tests (DST)
Test number	From depth MD [m]	To depth MD [m]	Choke size [mm]
1.0	815	865	0.0

Drill stem tests (DST)
Test number	Final shut-in pressure [MPa]	Final flow pressure [MPa]	Bottom hole pressure [MPa]	Downhole temperature [°C]
1.0				33

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		1081		0.630

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
BGF-A	1480	1862
CST GR	1390	1830
DLL MSFL LDL CNL LSS BGT GR SP A	502	1070
DLL MSFL LDL CNL LSS GR SP AMS	1096	1662
DSI HLDT CNT NGT AMS	1373	1867
FMS-B GR AMS	1600	1868
IRTJ ECD-C GR	1650	1732
MWD - GR RES DIR	105	1684
MWD - GR RES DIR	1380	1876
SMRS MDLT GR SP AMS	1373	1867
SRFT GR	1675	1797
USIT CBL VDL GR CCL	1650	1732
VSP	1096	1662

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
SURF.COND.	30	235.0	36	235.0	0.00	LOT
INTERM.	18 5/8	563.0	24	563.0	0.00	LOT
INTERM.	13 3/8	1180.0	17 1/2	1180.0	1.77	LOT
INTERM.	7	1688.0	8 1/2	1688.0	1.86	LOT
OPEN HOLE		1875.0	6	1875.0	0.00	LOT

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Visc. [mPa.s]	Mud type
563	1.03	16.0	WATER BASED
1028	1.30	28.0	WATER BASED
1180	1.06	16.0	WATER BASED
1183	1.13	25.0	WATER BASED
1207	1.30	28.0	WATER BASED
1290	1.28	23.0	WATER BASED
1385	1.30	27.0	WATER BASED
1585	1.28	23.0	WATER BASED
1688	1.20	21.0	WATER BASED
1690	1.04	28.0	DUMMY
1701	1.08	285.0	DUMMY
1702	1.04	24.0	DUMMY
1702	1.04	23.0	DUMMY
1712	1.30	32.0	WATER BASED
1720	1.08	28.0	DUMMY
1732	1.08	24.0	DUMMY
1740	1.25	18.0	WATER BASED
1778	1.08	28.0	DUMMY
1819	1.30	35.0	WATER BASED
1860	1.25	38.0	DUMMY
1875	1.30	35.0	WATER 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]
2358_Formation_pressure_(Formasjonstrykk)	pdf	0.17

25/11-18