Wellbore: 591-L - 34/10-33 - 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.	34/10-33
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.	GULLFAKS SØR
Discovery Name of the discovery the wellbore is related to.	34/10-2 Gullfaks Sør
Well name Official name of the parent well for the wellbore based on Norwegian Offshore Directorate guidelines for designation of wells and wellbores.	34/10-33
Seismic location Position of spud location on seismic survey lines. SP: shotpoint.	ST 8134 - 156 CELLEPKT. 296
Production licence Official designation of the production licence the wellbore was drilled or planned to be drilled from ( well head posistion).	050
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.	591-L
Drilling facility Norwegian Offshore Directorate's name of the facility which the wellbore was drilled from.	WEST DELTA
Drilling days Number of days from wellbore entry to wellbore completion.	82
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,	25.09.1988
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.	15.12.1988
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.	15.12.1990
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.	01.01.2012
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
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/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.	MIDDLE 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.	BRENT GP
Kelly bushing elevation [m] Elevation of the rotary kelly bushing (RKB) above mean sea level.	29.0
Water depth [m] Depth in metres betweem mean sea level and sea floor.	134.0
Total depth (MD) [m RKB] Total measured length of wellbore from kelly bushing to total depth (driller's depth).	3870.0
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).	3850.0
Maximum inclination [°] Maximum deviation, in degrees, from a vertical well path.Shown only for released wells.	20
Bottom hole temperature [°C] Estimated temperature at final total depth of the wellbore. Shown only for released wells. See discription.	135
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 JURASSIC
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.	STATFJORD GP
Geodetic datum Reference system for coordinates. Example of legal values: ED50.	ED50
NS degrees Geographic coordinate of the wellhead, north-south degrees.	61° 7' 34.44'' N
EW degrees Geographic coordinate of the wellhead, east-west degrees.	2° 12' 57.1'' E
NS UTM [m] Universal Transverse Mercator coordinate of the wellhead, north-south.	6777262.00
EW UTM [m] Universal Transverse Mercator coordinate of the wellhead, east-west.	457756.18
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.	1302

Well 34/10-33 was the sixth well drilled to reservoir level on the Gullfaks South structure. The main objective of the well was to appraise the oil and gas reserves in the Brent Group on the northern part of the structure. The gas/oil and oil/water contacts were to be confirmed at 3324 m and 3395 m MSL respectively. Secondary objective was to penetrate 50 m of the Statfjord Formation to obtain data to better understand the structural development in the area, and also update the geological model for the upper part of the formation. A positive result would lead to the drilling of a horizontal testing well as a sidetrack from this well.

Operations and results

Well was spudded with the semi-submersible installation West Delta on 25 September 1988 and drilled to TD at 3870 m in the Early Jurassic Statfjord Formation. There was some shallow gas at 477 - 478 m. Due to this the 20" casing was set at 450 m. There was a problem with a leakage in the BOP. The drill string got stuck when setting the 13 3/8" casing and the MWD and drill bit had to be changed. The well was close to vertical down to ca 2500 m. From there the well built inclination gradually up to 20 deg at TD. At TD true vertical depth is estimated to be ca 20 m less than measured depth. The well was drilled with spud mud down to 483 m, with gypsum/polymer mud from 483 m to 3161 m, and with gel/lignosulphonate/lignite mud from 3161 m to TD.

Top Brent Group, Tarbert Formation came in at 3186 m with gas and oil. FMT data showed a gas/oil contact at 3268 m, 85 m higher than prognosed. Approximately 150 m of oil was found vertically down to top Dunlin Group at 3424 m, much more than expected. No oil/water contact was seen. There was a pressure shift of 1.5 - 2 bar at around 3350 m, indicating two separate compartments in the oil zone. This had not been observed in the previous wells on Gullfaks South. Due to the large amount of oil in the Brent Group, the oil in place estimate was adjusted to 50 - 60 million Sm3.

Eighteen cores were cut in the well. One core was cut from 3152 to 3161.5 m, 14 cores in the interval 3188 to 3435 m and 3 cores from 3799 to 3840 m. The core depth was found to be from 1.00 to 3.75 m less than loggers' depth. Segregated fluid samples were obtained at 3314 m in the Ness Formation and at 3368 m in the thin Etive Formation. Sampling was attempted also at 3406 and 3406.2 m in the Rannoch Formation, but due to very low permeability no formation fluid was obtained.

The well was plugged back and classified as an oil and gas appraisal well. West Delta started the sidetrack 34/10-33A 15.12.88 at 18.30 hrs.

Testing

Four DST tests were performed in this well.

DST 1.1 tested the interval 3378 - 3394 m in the Rannoch Formation and produced 289 Sm3 oil and 51000 Sm3 gas /day through a 12.7 mm choke in the main flow. The GOR was 176, the oil density was 0.859 g/cm3, and the gas gravity was 0.680 (air = 1).

DST 1.2 tested the combined intervals 3378 - 3394 m in the Rannoch Formation plus 3359 - 3374 m in the Ness/Etive Formations and produced 1318 Sm3 oil and 211900 Sm3 gas /day through a 28.6 mm choke in the final flow. The GOR was 161, the oil density was 0.856 g/cm3, and the gas gravity was 0.685 (air = 1). The reservoir temperature measured in the test was ca 123 deg C at reference depth 3373 m.

DST 2.1 tested the interval 3279 - 3307 m in the Ness Formation and produced 850 Sm3 oil and 376700 Sm3 gas /day through a 19.1 mm choke in the main flow. The GOR was 443, the oil density was 0.850 g/cm3, and the gas gravity was 0.665 (air = 1).

DST 2.2 tested the combined intervals 3279 - 3307 m and 3311.5 - 3329 m, both within the Ness Formation, and produced 1403 Sm3 oil and 302100 Sm3 gas /day through a 19.1 mm choke in the main flow. The GOR was 215, the oil density was 0.851 g/cm3, and the gas gravity was 0.660 (air = 1). The reservoir temperature measured in the test was ca 122 deg C at reference depth 3301.5 m.

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]
480.00	3668.00

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
2	3188.0	3197.0	[m ]
3	3199.0	3218.7	[m ]
4	3223.0	3234.7	[m ]
5	3235.0	3250.9	[m ]
6	3251.0	3271.0	[m ]
7	3273.5	3283.2	[m ]
8	3285.5	3298.0	[m ]
9	3289.5	3307.6	[m ]
10	3308.0	3336.0	[m ]
11	3336.0	3348.9	[m ]
12	3349.5	3373.0	[m ]
13	3373.0	3382.5	[m ]
14	3382.5	3410.3	[m ]
15	3410.5	3434.9	[m ]
16	3799.0	3815.7	[m ]
17	3815.5	3825.9	[m ]
18	3830.0	3840.0	[m ]

Cores at the Norwegian Offshore Directorate
Total core sample length [m]	279.7

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

Core photos

Core photos

3188-3192m	3192-3197m	3199-3202m	3202-3207m	3207-3211m

3211-3216m	3216-3218m	3226-3230m	3230-3234m	3235-3239m

3239-3243m	3243-3248m	3248-3250m	3250-3254m	3254-3259m

3259-3263m	3263-3267m	3267-3271m	3273-3278m	3278-3282m

3282-3283m	3285-3289m	3285-3294m	3294-3297m	3297-3302m

3302-3306m	3306-3307m	3308-3312m	3312-3316m	3316-3320m

3320-3325m	3325-3329m	3329-3333m	3333-3336m	3336-3340m

3340-3344m	3344-3348m	3349-3353m	3353-3357m	3357-3362m

3362-3366m	3366-3370m	3370-3373m	3373-3377m	3377-3381m

3381-3382m	3382-3387m	3387-3391m	3391-3395m	3395-3399m

3398-3403m	3403-3407m	3407-3410m	3410-3415m	3415-3418m

3418-3423m	3423-3427m	3427-3431m	3431-3434m	3431-3434m

3799-3803m	3803-3807m	3807-3811m	3811-3815m	3815-3820m

3820-3824m	3824-3828m	3828-3829m	3830-3834m	3834-3838m

3838-3840m

Palynological slides at the Norwegian Offshore Directorate

Palynological slides at the Norwegian Offshore Directorate
Sample depth	Depth unit	Sample type	Laboratory
3147.5	[m]	DC	GEOCH
3152.0	[m]	C	GEOCH
3152.5	[m]	C	GEOCH
3152.9	[m]	C	GEOCH
3153.4	[m]	C	GEOCH
3153.8	[m]	C	GEOCH
3154.0	[m]	C	GEOCH
3154.5	[m]	C	GEOCH
3155.6	[m]	C	GEOCH
3156.0	[m]	C	GEOCH
3156.5	[m]	C	GEOCH
3157.0	[m]	C	GEOCH
3158.5	[m]	C	GEOCH
3159.0	[m]	C	GEOCH
3159.5	[m]	C	GEOCH
3160.0	[m]	C	GEOCH
3161.2	[m]	C	GEOCH

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	TEST1,1	3378.00	3394.00		29.11.1988 - 00:00	YES
DST	TEST2	0.00	0.00		08.12.1988 - 09:00	YES
DST	TEST2,1	3279.00	3307.00	OIL	08.12.1988 - 07:31	YES

Lithostratigraphy

Lithostratigraphy
Top depth [mMD RKB]	Lithostrat. unit
163	NORDLAND GP
915	UTSIRA FM
956	NO FORMAL NAME
980	HORDALAND GP
1035	NO FORMAL NAME
1145	NO FORMAL NAME
1253	NO FORMAL NAME
1520	NO FORMAL NAME
1568	NO FORMAL NAME
1616	NO FORMAL NAME
1827	ROGALAND GP
1827	BALDER FM
1907	LISTA FM
2055	SHETLAND GP
2055	JORSALFARE FM
2350	KYRRE FM
3014	CROMER KNOLL GP
3014	MIME FM
3028	VIKING GP
3028	DRAUPNE FM
3057	HEATHER FM
3186	BRENT GP
3186	TARBERT FM
3234	NESS FM
3365	ETIVE FM
3374	RANNOCH FM
3424	DUNLIN GP
3424	DRAKE FM
3514	COOK FM
3629	BURTON FM
3676	AMUNDSEN FM
3799	STATFJORD GP

Geochemical information

Geochemical information
Document name	Document format	Document size [MB]
1302_1	pdf	0.32
1302_2	pdf	0.48
1302_3	pdf	0.34
1302_4	pdf	0.64

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]
1302_01_WDSS_General_Information	pdf	0.26
1302_02_WDSS_completion_log	pdf	0.26

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]
1302_34_10_33_Completion_log	pdf	3.19
1302_34_10_33_Completion_report_1	pdf	47.33
1302_34_10_33_Completion_report_II	pdf	40.30

Drill stem tests (DST)

Drill stem tests (DST)
Test number	From depth MD [m]	To depth MD [m]	Choke size [mm]
1.0	3378	3394	12.7
1.3	3359	3374	28.6
2.1	3279	3307	19.1
2.2	3279	3329	19.1

Drill stem tests (DST)
Test number	Bottom hole pressure [MPa]	Downhole temperature [°C]
1.0	21.000
1.3	30.000	123
2.1	32.000
2.2	43.500	122

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	288	51000	0.854	0.680	176
1.3	1318	211900	0.856	0.680	161
2.1	850	376700	0.850	0.665	443
2.2	1403	302100	0.850	0.660	218

Logs

Logs
Log type	Log top depth [m]	Log bottom depth [m]
AC WAVETRAIN	2831	3432
ACDIP GR MISRUN	0	0
CBL VDL GR	163	1829
CBL VDL GR	2410	3146
CBL VDL GR	2994	3771
CDL CN GR	3771	3871
CDL GR CAL	225	3150
DIFL ACL GR	225	3150
DIFL ACL GR	3771	3871
DIFL CDL CN SL	3146	3768
DIPS GR	2850	3870
DLL MLL ACL GR	3146	3772
FMT GR	3188	3414
FMT GR	3188	3406
FMT GR	3368	3517
FMT GR	3406	3406
MWD - SN GR	231	3152
MWD - SN GR	3161	3186
MWD - SN GR	3435	3776
VESLOCITY	800	3770

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	225.0	36	226.0	0.00	LOT
SURF.COND.	20	459.0	26	466.0	1.43	LOT
INTERM.	13 3/8	1828.0	17 1/2	1844.0	1.53	LOT
INTERM.	9 5/8	3148.0	12 1/4	3161.0	1.99	LOT
LINER	7	3769.0	8 1/2	3776.0	1.96	LOT
OPEN HOLE		3870.0	6	3870.0	0.00

Drilling mud

Drilling mud
Depth MD [m]	Mud weight [g/cm3]	Visc. [mPa.s]	Yield point [Pa]	Mud type	Date measured
470	1.10	12.0	3.0	WATER BASED	06.10.1988
592	1.10	12.0	3.0	WATER BASED	07.10.1988
2153	1.25	18.5	3.5	WATER BASED	14.10.1988
2322	1.25	15.0	3.0	WATER BASED	17.10.1988
2590	1.25	18.0	3.8	WATER BASED	17.10.1988
2709	1.25	17.0	5.5	WATER BASED	17.10.1988
2931	1.28	16.0	4.8	WATER BASED	18.10.1988
3014	1.34	18.0	6.2	WATER BASED	19.10.1988
3111	1.40	23.0	8.6	WATER BASED	20.10.1988
3161	1.45	21.0	6.0	WATER BASED	24.10.1988
3161	1.45	18.0	5.5	WATER BASED	24.10.1988
3174	1.45	21.0	6.0	WATER BASED	26.10.1988
3199	1.45	20.0	4.5	WATER BASED	26.10.1988
3223	1.49	21.0	6.0	WATER BASED	27.10.1988
3251	1.49	21.0	6.0	WATER BASED	01.11.1988
3280	1.49	23.0	7.0	WATER BASED	01.11.1988
3286	1.53	21.0	6.5	WATER BASED	01.11.1988
3293	1.53	24.0	6.0	WATER BASED	01.11.1988
3329	1.53	24.0	7.0	WATER BASED	02.11.1988
3350	1.53	24.0	6.5	WATER BASED	02.11.1988
3377	1.53	22.0	6.0	WATER BASED	03.11.1988
3411	1.53	20.0	6.0	WATER BASED	04.11.1988
3602	1.53	75.0	8.0	WATER BASED	07.11.1988
3619	1.50	21.0	4.0	WATER BASED	29.11.1988
3763	1.49	19.0	5.0	WATER BASED	21.11.1988
3765	1.50	23.0	8.5	WATER BASED	11.11.1988
3766	1.50	17.0	6.5	WATER BASED	14.11.1988
3776	1.50	19.0	8.5	WATER BASED	14.11.1988
3776	1.50	19.0	9.0	WATER BASED	14.11.1988
3776	1.50	19.0	6.5	WATER BASED	15.11.1988
3776	1.50	17.0	6.0	WATER BASED	17.11.1988
3776	1.50	21.0	6.0	WATER BASED	21.11.1988
3776	1.50	26.0	9.0	WATER BASED	17.11.1988
3793	1.40	22.0	6.5	WATER BASED	21.11.1988
3815	1.40	23.0	6.5	WATER BASED	22.11.1988
3831	1.40	19.0	5.0	WATER BASED	25.11.1988
3870	1.40	22.0	5.5	WATER BASED	25.11.1988

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]
1302_Formation_pressure_(Formasjonstrykk)	pdf	0.22

34/10-33