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Whiting Petroleum Corporation

WHITING REFRAC PROGRAM November 2017

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Williston Basin Bakken/Three Forks Today

▪ To date, 12,000 -13,000 wells that have penetrated the Bakken

▪ Whiting operates around 1,400 of those horizontal wells

SPE-180414, Gullickson, et al

▪ Meridian Oil, first

Bakken Hz in 1987

▪ Early horizontal wells (2006-2010) were limited by technology

▪ Map shows surface locations of Bakken and Three Forks wells (Bakken in Orange, Three Forks in Blue)

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Wellbore Review

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What is a “Frac” and What does it look like

▪ “Frac” is short for Hydraulic Fracture Stimulation Treatment

▪ First pumped in 1947 in Kansas in a vertical natural gas well

▪ Goal: Create a highly conductive path between the formation and the wellbore, in order to accelerate and enhance recovery of reserves

Whiting frac East of Williston

Artist’s rendering of what a frac looks like

What a frac really looks like

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What is a “Frac” - How’s it done and what’s in it?

▪ How it’s done: Pump water, sand and chemicals at a high rate, in excess of the ability for fluid to leak-off into the formation, overcoming the mechanical stress of the formation, resulting in hydraulically “splitting” the rock

▪ Primary constituents are Water and Sand, some chemicals as well

100 Mesh

30/50 Mesh

40/70Mesh

20/40Mesh

Linear Gel Cross-Linked GelSlickwater

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What is a “Frac” – How much do we pump?

▪ Typical Bakken or Three Forks Horizontal well Frac job

▪ Water: 200,000 to 300,000 barrels per well

(about 18 Olympic Sized Swimming Pools)

▪ Sand: 8,000,000 lbs to 15,000,0000 lbs per well

(sand for 27 wells could fill ND State Capitol Building)

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Common Completions for Horizontal Wells

▪ Early generation completions, little control over location of fractures

▪ Later generation completions, more control, more entry points, better overall performance

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Refrac – What is it, and how is it done?

▪ Operationally, a refrac is very similar to a typical frac

▪ Possibly easier from an execution standpoint (fewer stages, minimal shut-downs, treating pressure is generally lower, etc.)

▪ Same “ingredients”

▪ Similar wellbore prep (ensuring integrity more challenging)

▪ Technique to recover more oil from existing wells

▪ Must contact new reservoir to do this

▪ Opportunity to address prop pack or flow assurance issues

▪ Degraded proppant pack, salt, scale?

▪ Re-connect the well to the formation

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Whiting 2014 Refrac Campaign Results

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Whiting 2016/17 Refrac Campaign Strategy

1. Extensive Candidate Selection Phase

1. Initial Screening

2. Root Cause Analysis

3. Candidate Classification

2. Design & Engineering

3. Economics & AFE’s

4. Job Execution

5. Feedback & IterationLocations of Whiting’s recent refracs

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Refrac Prep & Execution - Example

▪ Add perfs between perfs

▪ Refrac designed to ‘dress-up’ existing fractures, then divert into new perfs and create more SRV

▪ Treatment pressure indicative of success

SPE-174819, Melcher, et al

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Diversion Material – for fracs and refracs

▪ Polylactic Acid (synthetic organic polymer), which is a biodegradable thermoplastic (generally derived from things like corn starch or tapioca root)

▪ Generally a mix of different shapes and/or mesh sizes

▪ Pumped using a separate pump from the rest of the horsepower to keep the ‘slugs’ concentrated

▪ The practice is evolving, some companies are seeking patents on their diversion process

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Diagnostics – Where did the refrac go?

▪ Post refrac, FiberCoil & monitor thermal recovery

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Whiting 2016/17 Refrac Campaign Results

▪ Dunn County refrac, October, 2016

▪ Cleaned-out, add perforations, refrac in 14 cycles with 2.4 MMlbsand, 60,000 bbl water

▪ Before: 25 BOPD

▪ After: 175 BOPD

▪ Economic project

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Whiting 2016/17 Refrac Campaign Results

▪ Sanish refrac, June, 2017

▪ Cleaned-out, add perfs refrac in 17 cycles with 3.6 MMlb sand, 80,000 bbl water

▪ Before: 25 BOPD

▪ After: 200 BOPD

▪ Early performance good

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Whiting 2016/17 Refrac Campaign Results

▪ Hidden Bench refrac, June, 2017

▪ Clean-out, add perfs, refrac in 27 cycles with 2.1 MMlb sand, 49,000 bbl water

▪ Before: 22 BOPD

▪ After: 370 BOPD

▪ Parent well refrac

▪ Child wells performing above expectations

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Whiting 2016/17 Refrac Campaign Results

▪ Tarpon refrac, June, 2017

▪ Cleaned-out, add perfs (jet cut), refrac in 17 cycles with 2.9 MMlb sand, 91,000 bbl water

▪ Before: 65 BOPD

▪ After: 450 BOPD

▪ Only refrac so far of cemented liner

▪ Used more aggressive diversion methods between each cycle

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Summary

▪ The Williston Basin has many existing wellbores

▪ Refracs are similar to regular fracs, but in some ways easier

▪ The same materials are used for refracs and fracs

▪ Refrac candidate selection is probably the most important component of success

▪ There is a growing number of successful refracs, getting more out of existing wells

▪ Technologies for performing refracs and measuring their effectiveness continue to improve