The NPD's Fact-pages
	Generated 31.07.2010

Exploration wellbore: 2/7-23 S

General information

Wellbore history

General

Well 2/7-23 S was the fourth well drilled on the South Eldfisk (Embla) Field, which consists of a faulted structural high of assumed Palaeozoic sediments and volcanics. The structure is located on the eastern boundary of the Grensen Nose, a prominent faulted terrace marking the western edge of the Central Graben. The purpose of the well was to test the northward extension of the hydrocarbon bearing sandstones discovered in the 2/7-9 well in 1974 and confirmed by tests in the 2/7-20 and 2/7-21 S wells. If reservoir was proven, the intent was to complete the well in a manner suitable for a later tie-back to a production facility, where it would provide a third drainage point for future field development of the Embla Field.

Operations and results

Appraisal well 2/7-23 S was spudded with the semi-submersible installation West Delta on 15 May 1990 and drilled to TD at 4760 m in indeterminate pre-Jurassic sandstone. The well was drilled from the third slot in a three-slot temporary template located over the 2/7-20 well. The 2/7-23 S well was deviated to a target location at the Base Cretaceous level 1227 m north of the wellhead. Shallow gas was encountered at 593 m and caused some operational problems. The drilling went on without significant problems to TD, but during preparations for testing the drill string got stuck. Attempts to work the pipe free met with no success and the pipe had to be cut. The remainder of the drill string could not be retrieved and it was decided to abandon the well without testing. The well was drilled using KCL/Soltex/Aktaflo-S water based drilling fluid down to the 9 5/8" casing depth at 4229 m. Below this point and for the remainder of the well Enviromul oil based mud was used.

The well penetrated 4 m of Late Jurassic shale (Mandal Formation) at 4408 m. The target pre-Jurassic reservoir sands were encountered at 4412 m, 74 m TVD deeper than prognosed. The reservoir was oil-bearing. No distinct oil-water contact was seen, but from electric logs and RFT pressure data an oil column of ca 200 m can be inferred.

Hydrocarbon shows were recorded between 1524 - 1645.9 m in base Nordland / top Hordaland Group as moderate to good dull yellow-brown fluorescence in the cuttings. Oil shows were also recorded in the Shetland Group, with peak shows at 3254 m in the Ekofisk Formation, at 3323 m in the Tor Formation, and at 3625.6 m, 3886.5 m, and at 3973 - 3977.6 m in the Hod Formation. Below 4229 m true oil shows could not be distinguished from the oil based mud

An attempted coring in the Early Cretaceous did not recover any core. Twenty cores were cut in the reservoir section with a total core recovery of 273 m. No wire line fluid samples were taken.

The well was suspended on 21 November 1990 as an oil appraisal well.

Testing

Due to technical problems no DST tests were performed in this well.

Cuttings available at the NPD

Interval [m]: 1085.00 - 5124.00

Cores available at the NPD

Core length [m]: 273.00

Scanned core photos

14520-14526ft	14526-14532ft	14532-14538ft	14538-14544ft	14544-14550ft
14550-14556ft	14556-14582ft	14562-14568ft	14568-14574ft	15086-15092ft
15092-15098ft	15098-15104ft	15104-15110ft	15110-15111ft	15111-15117ft
15117-15123ft	15123-15129ft	15129-15135ft	15135-15141ft	15141-15147ft
14574-14580ft	15147-15153ft	15153-15159ft	15159-15165ft	15165-15171ft
15171-15174ft	15174-15180ft	15180-15186ft	15186-15192ft	15192-15198ft
15198-15204ft	14580-14588ft	15204-15210ft	15211-15217ft	15217-15223ft
15223-15229ft	15229-15235ft	15235-15241ft	15241-15247ft	15247-15253ft
15253-15257ft	15257-15263ft	14586-14592ft	15263-15269ft	15269-15275ft
15275-15281ft	15281-15287ft	15287-15293ft	15293-15296ft	15296-15302ft
15302-15308ft	15308-15314ft	15314-15320ft	14592-14598ft	15320-15326ft
15320-15328ft	15329-15335ft	15335-15341ft	15341-15347ft	15347-15353ft
15353-15359ft	15359-15365ft	15365-15371ft	15371-15377ft	14598-14604ft
15377-15383ft	15383-15389ft	15389-15390ft	15396-15402ft	15402-15408ft
15408-15414ft	15414-15420ft	15420-15426ft	15426-15432ft	15432.-15438ft
14604-14610ft	15438-15444ft	15444-15450ft	15450-15456ft	15456-15462ft
15462-15468ft	15468-15474ft	15474-15480ft	14610-14615ft	14615-14619ft
14619-14625ft	14625-14631ft	14631-14637ft	14637-14643ft	14643-14647ft
14647-14653ft	14653-14658ft	14658-14663ft	14663-14669ft	14669-14675ft
14675-14681ft	14681-14687ft	14687-14692ft	14692-14698ft	14698-14704ft
14704-14710ft	14710-14718ft	14716-14721ft	14721-14727ft	14727-14733ft
14733-14739ft	14739-14745ft	14745-14749ft	14749-14755ft	14755-14761ft
14761-14767ft	14767-15773ft	14773-14776ft	14777-14783ft	14783-14789ft
14789-14795ft	14795-14795ft	14795-14801ft	14801-14807ft	14807-14813ft
14814-14820ft	14820-14828ft	14826-14832ft	14832-14838ft	14838-14843ft
14843-14849ft	14849-14855ft	14855-14857ft	14857-14863ft	14863-14869ft
14869-14875ft	14875-14881ft	14881-14886ft	14886-14892ft	14892-14898ft
14899-14905ft	14905-14911ft	14911-14913ft	14913-14919ft	14919-14925ft
14925-14931ft	14931-14937ft	14937-14943ft	14943-14949ft	14949-14955ft
14955-14961ft	14961-14967ft	14967-14973ft	14974-14975ft	14975-14981ft
14981-14987ft	14987-14993ft	14996-15002ft	15002-15008ft	15008-15014ft
15014-15020ft	15020-15026ft	15026-15032ft	15032-15038ft	15038-15044ft
15044-15050ft	15050-15056ft	15056-15062ft	15062-15068ft	15068-15074ft
15074-15080ft	15080-15086ft

Palynological slides available at the NPD

Oil samples available at the NPD

No oil samples available.

Casing and leak-off tests

Mud

Drill stem test

No drill stem test in this wellbore.

Available logs

Lithostratigraphy

Composite log

No composite log presently available.

Geochemical information

You need an ACROBAT reader from ADOBE  to display the reports in pdf format.

Documents reported by the licencees (period for duty of secrecy expired)

No documents presently available.

Old NPD WDSS reports, NPD papers and other related documents

You need an ACROBAT reader from ADOBE  to display the reports in pdf format.