31/2-14
Export: PDF
-
General information
-
Wellbore history
GeneralAppraisal well 31/2-14 was drilled on the north-western margin of the Troll field. The main objectives of the well were to demonstrate the production potential for oil in the northern part of the Troll oil province, to evaluate the proposed template development scheme and to confirm the predicted extension of high energy progradation sands in the northern region.Operations and resultsWell 31/2-14 was spudded with the semi-submersible installation Borgny Dolphin on 23 April 1984 and drilled to TD at 1725 m in the Middle Jurassic Fensfjord Formation. The site survey before spud showed, as usual for the area, a seabed with numerous pockmarks (12 pockmarks/km3 on average). After setting the 13 3/8" casing shoe at 1498 m a leak in the kill-line was discovered, leading to repairs of the BOP and replacement of the marine riser. After 10 days lost time normal operations could resume. The well was drilled with seawater and hi-vis pills down to 814 m, with KCl/polymer mud from 814 m to 1513 m, and with chalk mud from 1513 m to TD.No sands were encountered above the Jurassic.The well encountered hydrocarbons in the Late Jurassic Sognefjord Formation. Top reservoir was penetrated at 1533 m (1508 m SS). The GOC was at 1566 m (1541 m SS) and the FWL was at 1592 m (1567 m SS). The oil-bearing interval consists of medium to low quality sands with a very clean layer (7m) some 3 m above the OWC. Below 1595 m (top Heather Formation) the sands are micaceous. The core measured permeability values range from 10 mD to 10 Darcy. In the gas bearing part of the cored interval no to weak fluorescence was recorded. In the oil zone (1561 - 1592 m) the fluorescence varied from weak to strong. Below 1594 m no fluorescence was recorded. Seven cores were cut from 1535 m to 1599 m in the Late Jurassic sequence. No samples were taken on wire line.The well was permanently abandoned on 21 June as a gas and oil appraisal.TestingThe clean sand interval 1583.3 - 1590.3 m in the oil zone was perforated and completed with an internal gravel. A long duration production test was carried out in an attempt to obtain gas breakthrough. The well was beaned up to 1335 Sm3 oil/day and flowed for 9.5 days. Gas breakthrough did not occur. The oil was a 28.1 deg API gravity oil with a GOR of 60 Sm3/Sm3. Maximum temperature recorded during the test was 68.3 deg. C, which correspond to a temperature gradient of 53 deg C/km above the reservoir. -
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]490.001725.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom11535.01542.2[m ]21544.51553.8[m ]31560.01562.9[m ]41564.01570.0[m ]51571.01576.9[m ]61580.01586.3[m ]71589.51598.2[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]46.3Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
-
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 availableDSTTEST-11590.001583.00OIL10.06.1984 - 00:00YES -
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 typeCONDUCTOR30464.036474.00.00LOTSURF.COND.20799.026810.01.37LOTINTERM.13 3/81498.017 1/21514.01.52LOTINTERM.9 5/81724.012 1/41725.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]BGT GR345515CBL VDL3641488CBL VDL9001690CET GR9001690CNL GR15301580CST15101602CST16041713GR CCL15501692ISF SONIC GR350814ISF SONIC GR8141506ISF SONIC GR15031719LDL CNL GR464814LDL CNL GR8141513LDT CNL SGT14961654MSFL DLL GR14961714RFT15331633SHDT GR14961718 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit36579913261326137514211526153015321532153315951685 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.23 -
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 nameDocument formatDocument size [MB]PDF8.20pdf2.69pdf0.39pdf1.27pdf1.27pdf0.39pdf2.69pdf0.16pdf3.33pdf0.62pdf0.09pdf0.06pdf0.05pdf3.08pdf0.52pdf0.10pdf0.06pdf0.07pdf2.00pdf1.02pdf0.91pdf0.96pdf1.13pdf1.27pdf1.54pdf0.89pdf1.54pdf0.53pdf0.89pdf0.53pdf2.69pdf2.00pdf1.02pdf0.91pdf2.69pdf0.16pdf1.27pdf0.05pdf3.33pdf0.62pdf0.09pdf0.06pdf3.08pdf0.52pdf0.10pdf0.06pdf0.07pdf0.96pdf1.13 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured5001.03WATER BASED5501.12WATER BASED6001.14WATER BASED6501.10WATER BASED7501.11WATER BASED8001.12WATER BASED8501.25WATER BASED9001.26WATER BASED10001.27WATER BASED12001.31WATER BASED12501.30WATER BASED15151.16WATER BASED15351.13WATER BASED15451.16WATER BASED15701.17WATER BASED