2/1-9 A
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General information
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Wellbore history
GeneralWell 2/1 ?9 A was drilled to appraise the 2/1-9 discovery in the Late Jurassic "Gyda sandstone member" (Ula Formation), by side-tracking up-dip to the crest of the Gyda South structure. If successful, the well could at a later stage be completed as a producer and tie back to Gyda platform. The structure is a fault/dip closure, which lies in the Late Jurassic fairway on the eastern flank of the Central Graben, 6 kilometres south of the Gyda field in the North Sea.Operations and resultsWell 2/1-9 was re-entered on 18 January 1992 by the semi submersible installation Ross Isle. The appraisal sidetrack well 2/1-9 A was kicked off in the 8 1/2" hole from 3270 m in the Late Cretaceous Tor Formation and drilled to TD 4379 m in the Late Jurassic Ula Formation. It took 25 1/2 days (18 1/2 days longer than planned) to drill to coring point at 4140 m. This delay was mainly due to difficulties in controlling the directional tendencies of the BHA's, which required a number of correction runs. In addition, poor bit performance and harder than expected formations exacerbated the slow progress. Hole inclination was 52.8 degrees at coring point. Problems were also experienced during TD logging with stuck logging tools and stuck pipe whilst attempting to retrieve the tool. In addition a 9 bbl influx had to be circulated out during this time. The well was drilled with Novamul ether-based mud from kick-off to TD.The target Ula Formation sandstone was encountered at 4099 m (3966 m TVD RKB). It was 120 m thick (TVD) and oil-bearing all through. The logs observed no OWC.Six cores (178 m) were cut in the 8 1/2" hole. All cores had 100% recovery with excellent shows being observed throughout. Core 1 to 5 covered the sandstone of the Ula Formation while core 6 entered into a mud stone member at the base. No H2S was observed whilst coring -despite having high level contingency due to H2S seen on well 2/1-9. The RFT was run and pressure points were recorded, but no fluid samples were taken.The well was suspended on 8 March 1983 as a potential future Gyda sub sea producer.TestingNo drill stem test was performed. -
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]3280.004379.00 -
Cores at the Norwegian Offshore Directorate
Cores at the Norwegian Offshore Directorate Core sample numberCore sample - top depthCore sample - bottom depthCore sample depth - uom14141.04178.0[m ]24178.04223.6[m ]34223.54251.5[m ]44251.54279.4[m ]54279.44307.4[m ]64307.54319.1[m ]Cores at the Norwegian Offshore Directorate Total core sample length [m]178.1Cores at the Norwegian Offshore Directorate Cores available for sampling?YES -
Core photos
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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 typeCONDUCTOR30164.036165.00.00LOTINTERM.20895.026896.00.00LOTINTERM.13 3/82893.017 1/22895.00.00LOTINTERM.9 5/83938.012 1/43940.00.00LOTLINER74378.08 1/24385.00.00LOT -
Logs
Logs Log typeLog top depth [m]Log bottom depth [m]DIL BHC GR AMS32724385LDL CNL GR AMS43204385RFT RPQS GR AMS41354298 -
Lithostratigraphy
Lithostratigraphy Top depth [mMD RKB]Lithostrat. unit891814289828982915292329823055314331593168316832563618378837993819381938703881390040684068408440994099 -
Composite logs
Composite logs Document nameDocument formatDocument size [MB]pdf0.51 -
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]pdf18.77 -
Drilling mud
Drilling mud Depth MD [m]Mud weight [g/cm3]Visc. [mPa.s]Yield point [Pa]Mud typeDate measured1400.0039.0OIL BASED32001.5670.0OIL BASED33001.5658.0OIL BASED33471.6079.0OIL BASED34641.5651.0OIL BASED35601.6080.0OIL BASED36811.6082.0OIL BASED38601.6087.0OIL BASED40001.6191.0OIL BASED42231.6290.0OIL BASED43181.6088.0OIL BASED43791.60101.0OIL BASED -
Palynological slides at the Norwegian Offshore Directorate
Palynological slides at the Norwegian Offshore Directorate Sample depthDepth unitSample typeLaboratory4142.6[m]CAPT4152.9[m]CAPT4157.4[m]CAPT4161.7[m]CAPT4166.0[m]CAPT4176.0[m]CAPT4179.0[m]CAPT4185.9[m]CAPT4195.0[m]CAPT4197.9[m]CAPT4213.7[m]CAPT4230.0[m]CAPT4248.0[m]CAPT4251.8[m]CAPT4263.0[m]CAPT4268.0[m]CAPT4274.0[m]CAPT4277.0[m]CAPT4282.6[m]CAPT4284.0[m]CAPT4290.5[m]CAPT4292.2[m]CAPT4292.4[m]CAPT4293.5[m]CAPT4295.0[m]CAPT4295.6[m]CAPT4296.0[m]CAPT4296.5[m]CAPT4297.5[m]CAPT4298.5[m]CAPT4299.4[m]CAPT4300.1[m]CAPT4300.7[m]CAPT4301.0[m]CAPT4301.5[m]CAPT4302.0[m]CAPT4303.2[m]CAPT4303.5[m]CAPT4304.0[m]CAPT4304.4[m]CAPT4304.7[m]CAPT4305.0[m]CAPT4305.3[m]CAPT4305.6[m]CAPT4313.2[m]CAPT4313.5[m]CAPT4314.1[m]CAPT4314.5[m]CAPT4314.9[m]CAPT4315.1[m]CAPT4316.2[m]CAPT4316.8[m]CAPT4316.9[m]CAPT4317.1[m]CAPT4317.4[m]CAPT4317.6[m]CAPT4317.9[m]CAPT4318.1[m]CAPT4318.2[m]CAPT4319.0[m]CAPT4319.1[m]CAPT