Well logs and core data from selected cored

intervals, National Petroleum Reserve, Alaska 

by Nelson, Philip H.

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, and Kibler, Joyce E.1

Open-File Report 01-167

2001 

This report is preliminary and has not been reviewed for conformity with U.S. Geological 

Survey editorial standards or with the North American Stratigraphic Code. Any use of 

trade, firm, or product names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

U.S. DEPARTMENT OF THE INTERIOR 

U.S. GEOLOGICAL SURVEY 

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U.S. Geological Survey, Denver, Colorado 
Well Logs and Core Data from Selected Cored Intervals 

National Petroleum Reserve, Alaska 

Philip H. Nelson and Joyce E. Kibler, U.S. Geological Survey

Denver, Colorado 

June 2001 

In June, 2001, the U.S. Geological Survey presented a core workshop, “Petroleum plays 

and systems in the National Petroleum Reserve – Alaska (NPRA)”, in conjunction with 

the Society for Sedimentary Geology and the American Association of Petroleum

Geologists. This collection of plots of well logs and core measurements includes all

cored intervals presented at that workshop (Table 1). 

The left-most track on the plots includes the gamma-ray and spontaneous potential (SP) 

logs, which are sensitive to lithology. The second track gives the depth in feet. 

The third track shows the resistivity logs, scaled in ohm-meters over two or three 

logarithmic cycles. The resistivity logs are of various types: deep induction (ILD), deep 

laterolog (LLD), shallow laterolog (LLS), laterolog 8 (LL8), spherically focused log

(SFLA_A), and 16-inch normal (R16 or SN). 

The fourth track includes the neutron log, scaled in percent porosity. The bulk density

log is scaled from 1.65 to 2.9 g/cc, so a sandstone with a grain density of 2.65 g/cc would 

have a porosity matching the neutron scale. The porosity measurements on core samples, 

labeled PORCORE, are scaled to match the neutron scale. Porosity increases to the left. 

Where available, total organic carbon (TOC) measurements, in weight percent, are also 

plotted in this track. 

Permeability measurements on horizontal plugs (PERMCORE) are plotted in the fifth 

track. Permeability, in millidarcies over four logarithmic cycles, increases to the left. 

The cored intervals (left red bar) and the intervals over which drill stem tests were

conducted (right green bar) are shown in the sixth track. 

Plots for all wells extend only over cored intervals, except the plot for the Lisburne well, 

which extends over the entire well. The Lisburne plot includes the sonic log and mud 

weight and also includes a color bar showing the Torok Formation and the thrusted repeat 

sections of the Lisburne and Etivluk Groups. 

Formation intervals were taken from Bird (1988), with a few modifications where Kemik 

Sandstone has been re-interpreted as Kingak Shale (Houseknecht, 2001). Well locations 

and well test results are also given by Bird (1988). Abbreviations for formation tops are 

used on the well log plots; these abbreviations are explained in Table 2. 

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References 

Bird, K.J., 1988, Alaskan North Slope stratigraphic nomenclature and data summary for 

government-drilled wells, Chapter 15 in Geology and exploration of the National 

Petroleum Reserve in Alaska, U.S. Geological Survey Professional Paper 1399, p. 317-

353. 

Houseknecht, D.W., 2001, Sequence stratigraphy and sedimentology of Beaufortian 

strata (Jurassic – Lower Cretaceous) in the National Petroleum Reserve – Alaska

(NPRA), in Houseknecht, D.W., ed., NPRA Core Workshop; Petroleum plays and 

systems in the National Petroleum Reserve – Alaska, SEPM Core Workshop No. 21, p. 

57-88. 

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Table 1. Plots listed alphabetically by well, with formations which were cored, and depth interval of the plot. 

Well Name Formations Cored Top of Plot Bottom of Plot File NaAtigaru Point 1 Basement Rocks 11180 11535 AtigaruDrew Point 1 Kingak Shale and Sag River Sandstone 6800 7080 DrewPtDrew Point 1 Shublik Formation 7050 7500 DrewPtDrew Point 1 Sadlerochit Group and Basement Rocks 7500 7950 DrewPtEast Simpson 1

Shublik Formation, Sadlerochit Group, and Basement Rocks 7400 7740 ESimp1

East Simpson 2 Sag River Sandstone 6600 6800 ESimp2East Simpson 2 Endicott Group and Basement Rocks 7140 7510 ESimp2Fish Creek 1 Nanushuk Group 2800 4150 FishCrkGrandstand 1 Nanushuk Group 750 1100 GrandsIkpikpuk 1 Shublik Formation 10150 10500 IkpikpuIkpikpuk 1 Lisburne Group 11650 12800 IkpikpuIkpikpuk 1 Basement Rocks 14800 15030 IkpikpuInigok 1 Torok Formation 3900 9100 Inigok-TInigok 1 Kingak Shale 9200 11800 Inigok-Inigok 1 Shublik Formation 12150 12450 Inigok-SInigok 1 Sadlerochit Group 12400 12800 Inigok-SInigok 1 Lisburne Group 13900 17150 Inigok-Inigok 1 Endicott Group 19200 19500 Inigok-J.W. Dalton 1 Sadlerochit Group 7880 8250 JWDaltJ.W. Dalton 1 Lisburne Group 8280 8580 JWDaltJ.W. Dalton 1 Basement 9150 9370 JWDaltKuyanak 1 Kingak Shale 5000 5200 KuyanaKuyanak 1 Basement Rocks 6500 6690 KuyanaLisburne 1 Lisburne Group 0 17000 LisburnMikkelson Bay State 1 Hue Shale and Pebble Shale Unit 11450 11700 MikkelsNorth Kalikpik 1 Torok Formation 3400 7000 NKalikpNorth Inigok Hue Shale (gamma ray zone) 7380 7580 NInigokOumalik 1 Torok Formation 4350 10920 OumaliPeard 1 Torok Formation 2400 6250 Peard-TPeard 1 Shublik Formation 8400 8600 Peard-S
Peard 1 Sadlerochit Group 8820 9050 Peard-S

Peard 1 Sadlerochit Group 9400 9600 Peard-SPeard 1 Basement Rocks 10000 10220 Peard-Phoenix Kingak Shale and Sag River Sandstone 7380 8300 PhoeniSouth Barrow 12 Sag River Sandstone and Basement Rocks 2150 2290 SBarroSouth Barrow 13 Basement Rocks 2400 2535 SBarroSouth Barrow 17 Sag River Sandstone 2250 2380 SBarroSouth Barrow 18 Kingak Shale 1650 1850 SBarroSouth Barrow 2 Basement Rocks 2400 2502 SBarroSouth Barrow 3 Basement Rocks 2700 2865 SBarroSouth Harrison Bay 1 Lisburne Group 10400 10700 SHarrisSeabee 1 Kingak Shale 13150 14650 SeabeeSimpson 1 Basement Rocks 6400 7000 SimpsoSquare Lake 1 Nanushuk Group 1510 3990 SquareTopagoruk 1 Basement Rocks 9970 10510 TopagoTulageak 1 Kingak Shale 2900 3100 TulageTulageak 1 Basement Rocks 3900 4020 TulageTunalik 1 Torok Formation 6200 10600 TunalikTunalik 1 Kingak Shale 10840 12650 TunalikTunalik 1 Lisburne Group 17030 17930 TunalikWest Dease 1

Sag River Sandstone, Shublik Formation, and Basement Rocks 3780 4170 WDeas

W.T. Foran 1 Lisburne Group 8160 8360 WTForWalakpa 1 Kingak Shale 1970 2130 WalakpWalakpa 1 Kingak Shale 2920 3120 WalakpWalakpa 1 Shublik Formation and Basement Rocks 3300 3670 WalakpWalakpa 2 Kingak Shale 2550 2750 WalakpWalakpa 2 Kingak Shale 2900 3100 WalakpWolf Creek 3 Nanushuk 1365 3600 WolfCr

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Table 2. Explanation of abbreviations used for formation names on plots. 

Abbreviation Formation Name NANU Nanushuk GroupTORO Torok FormationGAMMA Gamma Ray ZoneHUE Hue ShalePBBL Pebble Shale Unit KEMI Kemik SandstoneLCU Lower Cretaceous UnconformityKING Kingak ShaleTBAR Top of Barrow sandstone, Kingak ShaleBBAR Bottom of Barrow sandstone, Kingak Shale SAGR Sag River SandstoneSHUB Shublik FormationFIRE Fire Creek Member of Ivishak FormationLEDG Ledge Sandstone Member of Ivishak Formation KAVI Kavik Member of Ivishak FormationECHO Echooka FormationLISB Lisburne GroupENDI Endicott GroupBASE Basement RocksTD Total Depth

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