Buenos Aires, 7 al 10 de agosto de 2012

Environmentally Friendly Drilling Fluids for Unconventional Shale

James Friedheim Quan GuoM-I SWACO

Shale Gas in Argentina

“Argentina is the country with the third highest geological potential for these

types of hydrocarbons (shale gas), after China and the United States”

Overview of Argentina Shale Gas Fields – (from Investment U article The Next Big Shale Gas Boom by Justin Dove, Investment U Research; Friday, October 7, 2011)

The study assessed the viability of 48 shale gas basins in 32 countries and estimated

Argentina’s shale gas reserves at 774 trillion cubic feet (TCF), 60 times greater than the country’s current conventional reserves.

Furthermore, Argentina possesses almost 12% of the global shale gas resources, with

the Neuquen Basis showing greatest potential.

- Annual Energy Outlook 2011

All Shale Not the Same!

High Reactivity Shale

• Massive structure • Lack of bedding planes

or evident laminations • Soft • Plastic • Sticky• CEC >20 meq/100g• Predominance of

Smectite

Moderate Reactivity shale

• Moderate laminated structure

• Bedding structure• Easily broken • Not plastic• CEC 10-20 meq/100 g • Presence of smectite

and Illite approximately similar proportion

Low Reactivity Shale

• Strongly laminated structure

• Fissile • Brittle (Break along

lamination) • Hard and firm

consolidation • Not sticky • CEC <10 meq/100g• Predominance of illite

Unconventional resource requires unconventional thinking

Traditional Fluids Selection Techniques May Not Apply…..

Effective and useful shale-fluids interaction tests – Shale Hydration Test, Dispersion Test, Slake Durability Test, …

These traditional shale-fluids interaction and fluids selection tests are not effective for gas shale

Shale Play – Fluid Design Each shale play is different

and fluids should be tailored for each formation

Shale plays are usually less reactive (swelling), but are micro-fractured and can be very easily destabilized by fluid or filtrate

The overburden is different Some High-Temperature

shale plays (such as Haynesville) demand temperature stability, good rheology and densities up to > 19 ppg

Marcellus Shale Core 6711.05 – 6711.6 ft

Smectite 4%

Illite 25%

Quartz 47%

Feldspar 10%

Pyrite 5%

Chlorite 6%

Ankerite 3%

CEC, (meq/100gr) 3

Permeability (nd) 19 @ 3000 psi

Permeability (nd) 6 @ 6000 psi

Porosity 10%

Total organic content 9%

Oil/Gas Shales Tend to be Hard and Organically Rich

Old Shales Still Can Be Unstable in Freshwater

Fracture Tendency Allows Water Access

OBM/SBM Still Drilling Fluid Predominately Used

• Advantages– Cost*– Readily available*– Good temperature stability– Provides good hole stability &

shale stability– Tolerates contaminants well– Low torque & drag while drilling

& running casing

• Concerns– Cost**– Availability**– Downhole losses

ConcernsEnvironmental Acceptability Toxic Compounds* Slow degradation Rates* Cuttings Disposal (except PARALAND)

Human Exposure Factors High vapor emissions Aromatic & Cyclic hydrocarbons in the

vapor, and consider carcinogenic*

*) diesel **)synthetics

Shale Gas Water-based Mud Design

Develop a low cost, environmentally friendly WBM drilling fluid (fresh water) for the shale plays

• Straight-forward, simple, cost-conscious design.

• Environmentally friendly – precludes the use of

chloride-containing materials.

• Provide shale stability to low-reactivity, fissile shale

Physical Plugging• Blocks entry of fluid into the

formation• No decrease in stability• Inert chemistry

Water invasion into the shale formations weakens the

wellbore – not so much a chemical process!– Normal fluid loss additives are not able to form a filter cake and

therefore cannot stop the invasion of fluids, especially water.

Focus more on wellbore stability than shale inhibition for long

open hole section using WBM

Address issue of lubricity for both drilling and running casing

Goal

Concept

high permeabilitythick filter cake

low permeabilityvirtually no filter cake

SMT (Shale Membrane Test)

Paper # • Paper Title • Presenter Name

Fluid at fixed flow rate and pressure

Pressurized with brine that matches the water activity

of the shale

Pressure differences ∆P(t) at top and

bottom are used to calculate permeability

properties

300 psiEpoxy

50 p

si

Top Cap

Base

Typical Test Regime1. Brine matches water

activity of the shale2. Brine/Drilling fluid3. Nanomaterial and

drilling fluid4. Can be repeated

several times

P1 P1

P2 P2

SMT Results† Atoka Shale

† ) Sensoy, T, Chenevert, M. E. and Sharma, M. “Minimizing Water Invasion in Shales Using Nanoparticles.” paper SPE 124429 presented at the 2009 SPE Annual Technical Conference and Exhibition, 4-7 October 2009, New Orleans, Louisiana.

P1 P1

P2 P2

What do we mean by Nano Particles?

CONFIDENTIAL INFORMATION © 2009 M-I L.L.C.

Barite – 15,000 nmWARP – 1,500 nmBarite – 15,000 nmWARP – 1,500 nmFlu virus – 150 nm

Barite – 15,000 nm WARP – 1,500 nmFlu virus – 150 nmNanoparticles – 15 nm

Silica Nanoparticle ScreeningDesign Considerations• Cost• Various coatings/treatments & Number of treatments• Reactive groups• Temperature stability• Rheology effects• Sizes 5-100 nm• Compatibility with ions in a range of concentrations Faster tests and better availability

than shale samples

5 nm 10-30 nm 40-50 nm 70-100 nm

Nanoparticle Characterization

• Cryo-Transmission Electron Microscopy (TEM) performed at Rice University

• Right image is the best performing sample• The images will be used to better understand their filtration behavior

40000x magnification, scale bar 50 nm40000x magnification, scale bar 50 nm

Optimizing Nanoparticle Loading

Full mud formulation designed for maximum efficiency

Loading reduced from 29% to 3% (10 ppb, Nanoparticle slurry)

Permeability reduction is permanent

Strong stabilization of shale by blocking fluid access

Step Test Fluid Permeability, nD Permeability Reduction, %

1 4% NaCl Brine 0.153 -

2 WBM with 3% w/v of nanosilica 0.0042 97.2%

3 4% NaCl Brine 0.0035 97.6%

General Fluid Formulation Duovis:xanthan based rheology modifier which gives us suspension properties

EMI-690sufonated styrene-butadiene copolymer with optimized fluid loss performance

Resinex:Phenol formaldehyde resin used for additional filtration control

Glydril GP 100:blend of glycols used for shale inhibition, fluid loss and baseline friction coefficient reduction

Lubricant:General purpose Lubricant for WBM, usually vegetable oil derivative

EMI-2545:Nanosilica solution for physical shale plugging

PRODUCT UNITS Concn FunctionFreshwater Vol % prn Base FluidDuovis ppb 0.75 - 1.5 RheologyEMI-690 ppb 1 - 3 Fluid lossResinex ppb 8 - 12 FiltrationEMI-2545 Vol % 3-5 Shale sealingLime ppb 0.1 - 0.3 AlkalinityGlydril GP100 Vol % 2 - 3 Filtration/lubricityBarite ppb prn DensityLube 945 Vol % 0 - 3 Lubricity

Property ValuePeriod Aged 16Temperature 150

Fann 35 viscometer data600 rpm 120300 rpm 46200 rpm 36100 rpm 246 rpm 83 rpm 610 s 610 min 8PV 28YP 18

EMS 2520

Fracture Shale Consideration

0

50

100

150

200

250

300

0 2 4 6 8 10 12 14 16

Pre

ssu

re (p

si)

Time (hrs)

Base mud

Base mud + Nano particles

Brine before mud

• Formulated drilling fluid with 10ppb nanoparticles (10% EMI-2545)

• 99% reduction in shale permeability

• Permeability reduction held after flushing with brine (88% after 6 hours)

Fracture

Additional Data on EMS 2520

Sample Medium Dosage Results (ppm)

NanoSilica Gen #7 20.0 ppb >500,000

NanoSilica Gen #7 10.0 ppb > 500,000

0 SGWBS NA 114,520

NanoSilica SGWBS 10 ppb 113,850

Effect of lubricant package seen at higher loadings

Mysid Shrimp testing both additive (nanosilica) and ShaleGas Drilling Fluid easily pass

LC50 protocol

Environmental Testing

Summary

Novel approach to shale stabilization specifically focused on Unconventional Shale Plays source Rock by physical plugging of Shale Pores utilizing Nanoparticles:

Provides high stability Especially coupled with designed fluid formulation (EMS-

2520) even for fractured shale Environmentally designed (freshwater (without chlorides)) Applicable for HT fluids Applicability to other type of shale

Couple with chemical inhibition Robust testing protocol Performance additives for enhanced lubricity

Thank You We would like to thank Dr Ji Lou for his

support and help on the SMT equipment and work.

Questions?