16/4-6 S
Export: PDF
-
General information
-
Wellbore history
GeneralWell 16/4-6 S was drilled on the Luno II prospect about 15 km south of the Edvard Grieg field on the Utsira High in the North Sea. The primary objective of the well was to prove petroleum in Middle to Late Jurassic reservoir rocks. Secondary objective was to test the hydrocarbon potential in underlying older rocks.Operations and resultsWildcat well 16/4-6 S was spudded with the semi-submersible installation Bredford Dolphin on 11 March 2013 and drilled to TD at 2233 m (2213 m TVD) in the Late Triassic Skagerrak Formation. No significant problem was encountered in the operations. The well was drilled with spud mud down to 610 m and with water based Performadril mud from 610 m to TD.Top of the target reservoir was reached at 1950 m (1931 m TVD). The target reservoir is capped by a 10 cm thick Cromer Knoll Group at 1950 m (1931 m TVD). The reservoir section consisted of a 248 m thick sandstone sequence assigned mainly to the Skagerrak Formation with the exception of the top four meters that could belong to the Vestland Group, based on the occurrences of a few questionable terrestrial palynomorphs of Middle Jurassic age. The reservoir contained a gross oil column of ca 45 metres down to an OWC at 1995 m (1975 m TVD). About 30 metres of the oil-bearing zone had good reservoir properties. The oil is saturated and is in contact with a thin gas zone at the top of the reservoir, above the tested zone. Below the OWC, there is a zone of biodegraded oil shows in contrast to the non-biodegraded oil above. This suggest that there has been more than one generation of hydrocarbons present. Diminishing oil shows are described intermittently down to the base of the cored section at 2024 m.Three cores were cut in the interval from 1943.5 in the Tor Formation to 2024 m in the Skagerrak Formation. The core recovery was 99.7 to 100%. The core depth is ca 1 m deeper than logger's depth for all three cores. MDT fluid samples were taken at 1951.34 m (wet gas), 1952.54 m (wet gas), 1966.39 m (oil), 1978.73 m (oil), 1991.29 (water with trace oil), 1995.9 m (water), and 2028.18 m (water).The well was permanently abandoned on 3 May 2013 as an oil discovery.TestingOne Drill Stem Test was performed from the interval 1960.6 to 1980.6 m. In the main flow the test produced 271 Sm3 oil and 53900 Sm3 gas /day through a 40/64" choke. The GOR was 209 Sm3/Sm3, the oil density was 0.85 g/cm3, and the gas gravity was 0.82 - 0.85 (air = 1). H2S and CO2 contents were low, ca 0.1 ppm and 0.1 %, respectively. The DST temperature was 76.6 °C. -
Cuttings at the Norwegian Offshore Directorate
Cuttings at the Norwegian Offshore Directorate Cuttings available for sampling?YESCuttings at the Norwegian Offshore Directorate Cutting sample, top depth [m]Cutting samples, bottom depth [m]620.002233.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11943.51968.7[m ]21968.71997.0[m ]31997.02023.9[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]80.4Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Oil samples at the Norwegian Offshore Directorate
Oil samples at the Norwegian Offshore Directorate Test typeBottle numberTop depth
MD [m]Bottom depth
MD [m]Fluid typeTest timeSamples availableDST0.000.00OIL23.04.2013 - 00:00YESMDT1966.390.00OIL04.04.2013 - 00:00NOMDT1952.500.00OIL04.04.2013 - 00:00NO -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit126126747950105310531077123216101778177817871831190819151915192219481951195119511951195519552198 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.01961198118.4Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.0Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.0325180 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]ADT PEX HRLA ECS HNGS19152148FMI HRLA PEX19312229FMI MSIP19152149MDT19522028MWD - GR RES DIR19161943MWD - GR RES NEU DEN SON DIR PWD19172144MWD - GR RES PWD DIR SON NEU6021921MWD - GR RES SON DIR PWD125605VSP3312210XL-ROCK19312207XPT CMR GR19302149 -
Casing and leak–off tests
Casing and leak–off tests Casing typeCasing diam.
[inch]Casing depth
[m]Hole diam.
[inch]Hole depth
[m]LOT/FIT mud eqv.
[g/cm3]Formation test typeCONDUCTOR30205.036205.00.00SURF.COND.20603.026610.01.95LOTPILOT HOLE610.09 7/8610.00.00OPEN HOLE615.017 1/2615.00.00INTERM.9 5/81915.012 1/41921.01.50FITOPEN HOLE2233.08 1/22233.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured13921.3953.0Water Based19071.3966.0Water Based19961.2030.0Water Based20061.2328.0Water Based20061.2027.0Water Based22331.2340.0Water Based