Study of the Niobrara Formation in the Borie Field Abdulaziz Muhanna Alhubil, Gabrijel Grubac, Joe Lawson, Rachael Molyneux & David Scadden

Introduction Purpose: to examine the Niobrara formation within the Borie Field and recommend practices and key characteristics when selecting a prospect Other shales have become major plays Evaluate well logs to determine properties within the Borie Field

Background Late Cretaceous chalky shale Underlies much of the Great Plains Oil has been produced from other areas of the Niobrara If production in the Niobrara increases it could bring an economic boom to Wyoming

Geology Primarily a type II kerogen Up to 6% TOC in Niobrara Production relies on natural fractures Interbedded organic shales with chalky reservoir Maturation very important

Map

Environment, Ethics & Safety Aquifer depletion Water disposal Truck traffic Proper cement

Environment, Ethics & Safety Water use requirements Installation of pipelines Frac fluid disclosure Ground water protection

Research 4 main areas of interest  Net thickness of the Niobrara, B-2, and Fort Hayes formations  Porosity  Water Saturation  Oil in Place Economics is key to our evaluation

Top of the Niobrara

Niobrara Total Thickness

B-2 Tops

B-2 Thickness

Thickness Determination

Fort Hayes Tops

Fort Hayes Thickness

Thickness Determination

Density & Neutron Log Porosity can be calculated by finding the bulk density from the log. Φ=(ρ ma -ρ b )/(ρ ma -1) ρ ma- matrix density, which is equal to 2.7 g/cc, because it is a carbonate, and is limestone. ρ b- which is found from the log. Porosity can be found directly from the log by reading the density log porosity

Density & Neutron Log Cont. Neutron logs measure the hydrogen content in a formation Neutron log porosity can be found directly from the log Average porosity will be used from density log and neutron log porosity Φ=(Φ n + Φ d )/2

Ex. of Density & Neutron Logs In this example for B-2 area B-2 thickness=14ft Φ d =0.19 Φ n =0.1 Φ =0.14 This log was from the WARREN LIVESTOCK well Latitude is Longitude is

Ex. of Density & Neutron Logs In this example for Fort Hayes area: Fort Hayes thickness=12ft Φ d =0.06 Φ n =0.12 Φ =0.9

Acoustic Log Porosity can be calculated by using Wyllie's equation: Φ=(Δt-Δt ma )/(Δt f - Δt ma ) Δt- is the interval time, it can be found from the log. Δt ma- the average slowness of the matrix which is equal to 46 μsec/ft. Δt f - the average fluid slowness which is equal to 189 μsec/ft.

Examples of Acoustic Log In this example in the B-2 area B-2 thickness=10 ft Δt=69 Φ=(69-46)/(189-46) Φ=16% This log was from the BMU well Latitude is Longitude is

Examples of Acoustic Log In this example for the Fort Hayes Fort Hayes thickness=5 ft Δt=58 Φ=(58-46)/(189-46) Φ=8%

Water & Oil Saturation

Cementation Exponent (m)

B-2 Water Saturation using different values of m

Fort Hayes Water Saturation using different values of m

Comparison a=1; n=2; m=2.2

Plot Results B-2 m-1.14 & Fort Hayes m possibilities  1-The left hand side of the plot is in the water zone and the rest of the points are between 50% and 100% water saturation.  2-All points are in the hydrocarbon zone and there are no points in the water zone (Niobrara has hydrocarbons everywhere) *Better idea when compared to the maturation plot where mature oil is around 15 Ω ⋅ m resistivity

TOC The concentration of organic material in source rocks as represented by the weight percent of organic carbon. 2-4 % disseminated through the Niobrara

Type I&II kerogen

General Idea about Niobrara TOC

Niobrara & Bakken Comparison

20 miles from Borie Field Oil window at 4500 feet

Bigger depth Higher temperature higher vitrinite reflectance thermally mature Higher resistivity – more probable oil generation

Oil In Place OOIP=(f*h*(1-S w )/B o )/ OOIP= 13.3 Mbbl, 19.3 Mbbl, 29.1 Mbbl Recovery Factor of 5% Recoverable OOIP= 667,810 bbl; 964,571 bbl; 1.5 Mbbl

Economics Cost to complete each well General range of IP’s Decline Analysis Profitability of different scenarios Conclusions

Economics Well Cost  Range from $3,000,000-$7,000,000 IP  Scenario Dependent Excellent – 1558 BOPD (Jake 2-01H) Poor – 30 BOPD Discount Rate  10%

Economics Oil Price  $80 spot price Operating Cost  $5 per barrel of oil produced Decline Type  Hyperbolic Decline Di, initial nominal exponential decline rate = 10% b = 1.25 Time Period  26 years of production

Economics Analysis  Good IP/Favorable Well Cost 1558 BOPD/$3,000,000  Good IP/Unfavorable Well Cost 1558 BOPD/$7,000,000  Poor IP/Favorable Well Cost 30 BOPD/$3,000,000  Poor IP/Unfavorable Well Cost 30 BOPD/$7,000,000

Economics Analysis  Good IP/Favorable Well Cost NPV = $6,413,000  Good IP/Unfavorable Well Cost NPV = $2,413,000  Poor IP/Favorable Well Cost NPV = -$2,819,000  Poor IP/Unfavorable Well Cost NPV = -$6,819,000

Economics Analysis  Break Even Point with favorable well cost 497 BOPD IP and 26 years of production  Hyperbolic Decline  NPV and profitability highly dependent on Initial Production rates.

Economics

Conclusions There are HC’s Oil saturation around 58% in B-2 B-2 is the thickest cleanest section of the Niobrara Consistent and encouraging porosity exists throughout target area(15%) Fort Hayes-accessible thickness, bad porosity (6%)

Recommendations Horizontal drilling  Helps to increase surface area in tight formation with small pay zone  Successful implementation Bakken Marcellus Eagle Ford

Recommendations Focus on Niobrara signatures  low gamma ray  high resistivity

Concerns Water for hydraulic fracturing?  Production Maturity  More mature zones  Borie 16-4H Logs showed oil Tests while drilling showed oil No producible oil  Maturity

Moving forward Establish best drilling regimen Determine effective frac techniques  CO 2 Safe fracturing practices Water concerns