7120/1-4 S
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General information
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Wellbore history
GeneralWell 7120/1-4 S was drilled on the 7120/1-3 Gotha structure, situated on the southern end of the Loppa High in the Barents Sea. The discovery well 7120/1-3 found oil and gas in Late Permian karst carbonates of the Røye Formation. The primary objective of 7120/1-4 S was to test the reservoir properties and hydrocarbon potential of the Gohta Karst prospect. The secondary objective was to test the reservoir properties and hydrocarbon potential of a potential sandstone sequences in the Kobbe, Klappmyss and Havert formations.Operations and resultsAppraisal well 7120/1-4 S was spudded with the semi-submersible installation Island Innovator on 23 May 2014 and drilled to TD at 2520 m (2520 m TVD) in the Late Permian Røye Formation. No significant problem was encountered in the operations. The well was originally planned as an "S" shaped well. This was due to geological hazards connected to a deep-seated fault. Since TD was set 450 m shallow to plan, no deviation was necessary and the well became vertical despite the "S" denotation in the well name. The well was drilled with seawater and hi-vis pills down to 665 m and with Aquadril mud from 665 m to TD.The well encountered blocky sandstones in the upper (764.5-802.5 m) Snadd Formation and thin sandstone beds in the lower Snadd target (interval 1200 to 1300 m), but the reservoirs proved water filled. The Kobbe and Klappmyss formations had no reservoir development. A 12.5 m thick mainly gas bearing conglomeratic sandstone unit (interval 2301-2313.5 m), was found at the Permo-Triassic boundary. This unit had pressure gradient almost identical to that of 7120/1-3, indicating a pressure communication between 7120/1-3 and 7120/1-4 S. Stratigraphic age is uncertain but it is likely of Late Permian to Early Triassic in age. Carbonates consisting of partly dolomitic limestones with thin claystone laminae were found from the base of the cored conglomerates/breccia at 2315.77 m to TD at 2520 m. The Gohta Karst reservoir was poorly developed to absent in this well. The carbonates were hydrocarbon bearing, but due to poor reservoir quality, it was not possible to establish an oil-water contact.Isolated hydrocarbon / oil shows were described at 750 m, 770 m, 850 m and 870 m. No further shows were observed before entering the conglomeratic breccia at 2301 m. Continuous shows were described from this depth to 2323 m, where it became more patchy. The deepest show described was at 2464 m.A total of 112.25 m core was recovered in the interval 2306 to 2419.16 m (99.2% total recovery). MDT fluid samples were acquired from one station at 2308.57 m. The samples contained condensate. Single flash of the condensate gave a GOR in the range 5800 to 6800 Sm3/Sm3, liquid condensate density in the range 0.724 to 732 g/cm3, and gas gravity in the range 0.667 to 0.670 (air = 1).The well was permanently abandoned on 3 August 2014 as an oil and gas appraisal well.TestingTwo DST's were conducted.DST 1A tested the carbonate oil zone in the interval 2335 to 2385 m. The test produced 30 Sm3 condensate and 160000 Sm3 gas through a 20/64" choke. It was found that the test produced gas from the gas zone above due to lack of cement behind the liner and that the tested carbonate interval contributed nothing to the flow.DST 1A+B tested the interval 2335 to 2385 m + the conglomeratic breccia gas zone in the interval 2295 to 2312 m. This test produced 140 Sm3 condensate and 700000 Sm3 gas /day through a 52/64" choke. The GOR was 4500 Sm3/Sm3, the liquid condensate density was 0.730 g/cm3 and the gas gravity was 0.699 (air = 1). H2S and CO2 was less than 1 ppm and 1.1 %, respectively. -
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]680.002520.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom12306.02332.6[m ]22333.02361.3[m ]32361.32364.2[m ]42364.52391.3[m ]52391.52419.2[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]112.3Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory680.0[m]DCROBERTSO700.0[m]DCROBERT720.0[m]DCROBERT730.0[m]DCROBERT740.0[m]DCROBERT750.0[m]DCROBERT760.0[m]DCROBERT780.0[m]DCROBERT800.0[m]DCROBERT820.0[m]DCROBERT840.0[m]DCROBERT860.0[m]DCROBERT880.0[m]DCROBERT900.0[m]DCROBERT920.0[m]DCROBERT940.0[m]DCROBERT960.0[m]DCROBERT980.0[m]DC1000.0[m]DCROBERT1020.0[m]DCROBERT1040.0[m]DCROBERT1060.0[m]DCROBERT1080.0[m]DCROBERT1100.0[m]DCROBERT1120.0[m]DCROBERT1140.0[m]DCROBERT1160.0[m]DCROBERT1180.0[m]DCROBERT1200.0[m]DCROBERT1220.0[m]DCROBERT1240.0[m]DCROBERT1260.0[m]DCROBERT1280.0[m]DCROBERT1300.0[m]DCROBERT1320.0[m]DCROBERT1340.0[m]DCROBERT1360.0[m]DCROBERT1380.0[m]DCROBERT1400.0[m]DCROBERT1430.0[m]DCROBERT1440.0[m]DCROBERT1460.0[m]DCROBERT1480.0[m]DCROBERT1500.0[m]DCROBERT1520.0[m]DCROBERT1540.0[m]DCROBERT1560.0[m]DCROBERT1580.0[m]DCROBERT1600.0[m]DCROBERT1620.0[m]DCROBERT1640.0[m]DCROBERT1660.0[m]DCROBERT1680.0[m]DCROBERT1700.0[m]DCROBERT1710.0[m]DCROBERT1725.0[m]DCROBERT1740.0[m]DCROBERT1755.0[m]DCROBERT1770.0[m]DCROBERT1785.0[m]DCROBERT1800.0[m]DCROBERT1815.0[m]DCROBERT1845.0[m]DCROBERT1860.0[m]DCROBERT1880.0[m]DCROBERT1910.0[m]DCROBERT1925.0[m]DCROBERT1940.0[m]DCROBERT1955.0[m]DCROBERT1970.0[m]DCROBERT1985.0[m]DCROBERT1995.0[m]DCROBERT2000.0[m]DCROBERT2015.0[m]DCROBERT2030.0[m]DCROBERT2045.0[m]DCROBERT2060.0[m]DCROBERT2075.0[m]DCROBERT2085.0[m]DCROBERT2100.0[m]DCROBERT2115.0[m]DCROBERT2131.0[m]DCROBERT2149.0[m]DCROBERT2167.0[m]DCROBERT2185.0[m]DCROBERT2203.0[m]DCROBERT2221.0[m]DCROBERT2239.0[m]DCROBERT2257.0[m]DCROBERT2275.0[m]DCROBERT2281.0[m]DCROBERT2287.0[m]DCROBERT2290.0[m]DCROBERT2293.0[m]DCROBERT2296.0[m]DCROBERT2299.0[m]DCROBERT2302.0[m]DCROBERT2306.0[m]DCROBERT2306.0[m]CAPT2307.3[m]CAPT2309.5[m]CROBERT2310.9[m]CAPT2312.1[m]CAPT2313.8[m]CROBERT2315.5[m]CAPT2315.5[m]CROBERT2317.7[m]CROBERT2323.8[m]CROBERT2323.8[m]CROBERT2327.4[m]CROBERT2328.9[m]CROBERT2343.9[m]CROBERT2352.3[m]CROBERT2358.5[m]CROBERT2368.7[m]CROBERT2373.8[m]CROBERT2386.8[m]CROBERT2393.0[m]CROBERT2396.7[m]CROBERT2409.0[m]CROBERT2418.4[m]CROBERT -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit3623623894514517337332274227422852301230123142314 -
Drill stem tests (DST)
Drill stem tests (DST) Test numberFrom depth MD
[m]To depth MD
[m]Choke size
[mm]1.02295238520.6Drill stem tests (DST) Test numberFinal shut-in pressure
[MPa]Final flow pressure
[MPa]Bottom hole pressure
[MPa]Downhole temperature
[°C]1.090Drill stem tests (DST) Test numberOil
[Sm3/day]Gas
[Sm3/day]Oil density
[g/cm3]Gas grav. rel.airGOR
[m3/m3]1.01407000000.7300.6994500 -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]DSL CN ZDL ORIT XMAC RTEX MLL21092516DSL FLEX MREX22002514DSL PCOR21592507DSL STAR HD ORIT UXPL21092508DSL VSP16592499GR MDT ADT23022452LWD - GR RES SON PWD DIR3611223LWD - LWD-GR ABRES PWD DEN CAL N11552520LWD - NBGR PWD RES DIR DEN CAL N20502305 -
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 typeCONDUCTOR30441.636445.00.00SURF.COND.20657.826665.01.28LOTPILOT HOLE675.09 7/8675.00.00INTERM.13 3/81217.017 1/21226.01.59FITINTERM.9 5/82111.012 1/42119.01.51LOTLINER72520.08 1/22520.00.00 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured3611.031.0Water Based4451.041.0Water Based4801.031.0Water Based6651.2014.0Water Based8401.1610.0Water Based8891.2018.0Water Based11571.2115.0Water Based19801.1612.0Water Based21191.2017.0Water Based23061.1620.0Water Based25201.1617.0Water Based