An Alternative To Diesel For Landing Drilling An Alternative To Diesel For Landing Drilling OperationsOperations

Lee ConnLee Conn

M-I SWACOM-I SWACO

Can Non-Aqueous Fluids (NAF) Be

Designed to Enhance Soil Quality?

Non Aqueous Base Fluid SelectionsBase Fluid Environmental Staircase

Diesel

Mineral Oil / EMO

Internal Olefins/Ester

Linear Alfa Olefins

Paraffin

Since the 1980’s, there has been a strong demand tocontinue to improve environmentcharacteristic of base fluidsbeing used offshore

Environmental Testing Protocols & Regulations Established

Primary Drivers for Base Fluid Selection

• Environmental - Regulatory compliance- Seabed impacts

• Commercial - Cheaper Base Fluids- Availability - Logistics

• Technical- Lower Viscosity

Comparison of Base Fluids

Base Fluid Density KV @ 40°C Flash Point HTS Biodegradation

(SG) (cSt) (°C) (°C) Aerobic Anaerobic

Desirable < 0.80 ALAP > 95 AHAP Yes Yes

Mineral Oil 0.790 2 - 3 > 95 > 200 ? No

LAO 0.776 2.26 113 > 200 Yes Yes

PAO 0.800 5 - 7 160 High Yes Yes

Ester 0.850 5 - 6 > 150 150 Yes Yes

Internal olefin 0.792 3.60 > 138 > 204 Yes Yes

Linear paraffin 0.773 2.50 > 100 > 170 Yes Yes

Land Drilling OperationDiesel Still The Base Fluid Of Choice Globally

Advantages

• Diesel oil is the cheapest

• Diesel oil is more readily available

• Diesel oil has good temperature stability

• Diesel oil provides good hole stability

• Diesel oil tolerates contaminants as well

Disadvantage

• Environmental Acceptability- Toxic Compounds- Slow degradation Rates

• Poor Human Exposure Characteristics- High vapor emissions- Aromatic & Cyclic

hydrocarbons in the vapor, and consider carcinogenic

Waste Management Hierarchy

Reduction at SourceReduction at Source

Recycle & ReuseRecycle & Reuse

RecoverRecover

TreatmentTreatment

ResponsibleResponsibleDisposalDisposal

Long Term Liability

Drilling Fluids & Waste Management Options

Waste Management / Disposal Options For NAF Cuttings

• Thermal- Incineration- Indirect heat for base fluid recovery (re-use base

fluid)

• Injection

• Haul to registered disposal site

• Cuttings treatment- Stabilization, bury on site

• Bioremediation

Non Aqueous Fluid (NAF) Design StrategyObjective – Creating a Soil Enhancing Product

• Identify - environmental issues with

traditional formulations- root causes in the chemistry

of the additives- products that enhance rather

than damage the environment

• Build a cost effective and technically competent mud system based on selected additives

• Design a cost-effective and dependable bio-remediation process that will meet a consistent environmental performance standard

Testing for Land TreatmentTesting for Land Treatment

Diesel

Environmental Issues With NAF SystemsReview of Drilling Fluid Components

Hydrocarbon Base Fluid Chemical Structure

• Aromatics

• Cyclic Compounds

• Olefins

• Linear ParaffinsDE

CR

EA

SIN

G T

OX

ICIT

Y

FO

R T

HE

SA

ME

Mol

. Wt.

C C C CC

C C C CC

C

C

C CC

CC C

C

C C

C

• Low molecular weight, linear structure biodegrades under aerobic conditions.

• Aromatics & cyclic more toxic than linear structures of same molecular weight.

Environmental Acceptance

Crude Oil

Diesel/MO

Linear Paraffins/Olefins

¹LTMO/²EMO/ Iso-Paraffins

1 Low toxicity mineral oil2 Enhanced mineral oil

HighlyBiodegradable

Slow and incompletebiodegradation

DecreasingToxicity

Bioremediation of diesel

GC/MS Diesel GC/MS Diesel after bioremediation

Incomplete Degradation Non degradable toxic residuals

Increased probability of future environmental liability

Bioremediation of mineral oil

10.00 20.00 30.00 40.00 50.00 60.00 70.000

5000000

1e+07

1.5e+07

2e+07

2.5e+07

3e+07

3.5e+07

4e+07

4.5e+07

Time-->

AbundanceTIC: IPAR-3.D

C19

C18

C17

C15

C16

C14

MO/EMO- Aromatics are removed and many normal paraffins are branched. - While less toxic than diesel they biodegrade slower than diesel.

Unresolved hydrocarbon isomers, including cyclic and branched hydrocarbons.

Bioremediation of linear paraffinsBioremediation of linear paraffins

GC/MS Linear Paraffins GC/MS Presence of hydrocarbons after bioremediation

Complete degradation No toxic residuals

Composting Results using Various Base Fluids

• LP concentrations fell from 13% to ~1% in 10 days.

• EMO concentrations did not fall significantly over 20 days

• LTMO concentrations fell to 5.5% after 20 days.

• Linear components of diesel fell to 3.3% after 20 days with much slower subsequent degradation.

Total HC Content

02468

10121416

0 5 10 15 20Time, Days

Hy

dro

ca

rbo

n

Co

nc

en

tra

tio

n,

%

Biobase 560 DF1 EDC95-11 Diesel

LP LTMO EMO

Base FluidBiodegradation & Toxicity Testing

Biodegradability of Various Base FluidsTreatment % Reduction of

HydrocarbonsBiodegradability Rank

C11-14 LP 97 1C12-17 LP 94 2Ester 91 3Isomerized Tetradecene C14 (IO) 83 4Diesel 61 5Branched Paraffin 43 6

Chloride

Diesel

Environmental Issues With NAF SystemsReview of Drilling Fluid Components

Internal PhaseInternal Phase

• Plant Toxicity

• Water Column Toxicity

Toxicity due to the high concentration of chlorides Toxicity due to the high concentration of salts

• Electrical Conductivity

• Lack of Biodegradation

Chlorides Are The Main ConcernChlorides Are The Main Concern

CMA gives optimal environmental performance with minimal residual conductivity. Acetates and Nitrates enhance soil productivity with minimal water column toxicity.

INTERNAL PHASE - Fluid Design Concept

TOXICITY OF DRILLING FLUIDS

0

20

40

60

80

100

120

ALFALFA GROWTH

% O

F R

EF

ER

EN

CE

EMERGENCE (%)

ROOTH LENGTH(cm/plant)

SHOOT MASS (mgdw t/plant)

Chloride

BariteDiesel

Environmental Issues With NAF SystemsReview of Drilling Fluid Components

Weighting Agent

• Barite does not enhance the quality of the soil where cuttings may be used for landfarming

• Hematite or Ilmenite promises to enhance the quality of iron poor soils, or with CaCO3 that can minimize issues with heavy metals and can be beneficial for plant growth.

Non Aqueous Fluid (NAF) For Land Drilling Non Aqueous Fluid (NAF) For Land Drilling Operation The SolutionOperation The Solution

- Unique Invert emulsion fluid designed solely for improved cleaning and remediation of contaminated cuttings

- Design to meet environmental discharge regulations (with correct processing) and improves HSE

- Recommended Fluid Design:

• Linear Paraffin or Linear Olefin

• CMA, KAc, or CaKNO3• Hematite, Illmenite, or

CaCO3

NAF-Land has standard mud properties similar to those of typical Synthetic- and Oil-Based Muds

History of SuccessHistory of Success

• Primary: Enhance production in tight gas sands

Sandstone has < 10 md permeability

Sensitive to WBM due to high clay content

• Secondary: Improve drilling performance

Stabilize shale units to reduce risk of hole problems experienced in previous wells

Cavings, ballooning, loss circulation, stuck pipe, side-tracks, well-abandonment

Sensitive to WBM due to high clay content

New Zealand Land Drilling OperationsDrivers For Fluid System Change

1 Must be a synthetically produced base fluid

“oil” has poor environmental image

lower toxicity usually associated with synthetics

Optimize environmental factors

high aerobic biodegradability

low toxicity

chlorides free

Low health & safety risk

avoid low flash points base fluids as they are classified as flammables

Field compatible mud properties of high mud weight fluid

avoid high viscosity => high ECD’s => loss circulation

Selection Criteria For Invert Emulsion

• Utilizing a combination of best available technologies / experience for system choice.

Internal phase + Continuous Phase

Nitrates Linear Paraffins

Experienced Based System

• Intervals : 16", 12.25", 8.5"

• MW : : 11.5 ppg - 16.0 ppg

• SWR : 80/20 - 85/15

• PV : 22 - 27 cps

• YP : 17 - 13 lb/100sq.ft

• Aw : 0.8 - 0.7

• ES : 400-600 volts

• HTHP FL : 1.0-3.0 mL

Mud Properties & Drilling Performance

1500

2000

2500

3000

3500

4000

4500

5000

1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55Days

Dept

h

Well 3WBM

Well 3STSBM

Rig-Site Handling of Cuttings

Blending with sawdust => haul-off

Disposal Method – Vermiculture BioremediationDisposal Method – Vermiculture Bioremediation

• Worm farm already established

• Still active today for processing drill cuttings received from land operation

• The end product of vermiculture is sold as fertilizer

Bangladesh - Landfarming

• Location- Tea plantation - Rice plantation

• Drilling fluid- Base – linear paraffin with

traces of branched molecules

- Acetate Internal Phase- barite

• Designated area protected by earthen barriers

Bangladesh - Landfarming

• Management- Organic material: rice hulls- Use of local work force- Frequent tilling to guarantee aeration of the soil- Use of fertilizers

Bangladesh - Landfarming

• Site Closure

- Reduction in TPH to 1% according to internal standards and best practices

- Area covered with local vegetation

- Duration of project: 6 months

- Total volume of cuttings treated: 3000 m³

Bio-remediation processes using Diesel can necessitate long time (1-3 years) and/or large land mass to meet regulations.

Changing the fluid formulation to an optimized highly degradable, low toxicity NAFdecrease remediation timesreduce environmental impact. Lower health & safety risk to personnel

Bioremediation processes have to be optimized for local conditions.

Summary