Land Application of Drill Cuttings

and Fluids

Chad J. Penn

Department of Plant and Soil Science

Oklahoma State University

chad.penn@okstate.edu

What is “land application”?

• Often used synonymously with the terms

“soil farming” or “land farming”

• Technically, land application is neither of

these

– “soil farming” and “land farming” are

remediation techniques for soils that have

become contaminated

– “land application” is a method of disposal

that aims to prevent contamination of soils

What is drilling mud? • Drilling mud is used for O&G Exploration

• Several uses for the drilling process

– Seal formations

– Remove/ suspend cuttings

– Lubricate and cool the drill bit

– Control corrosion on drill stem

– Control well bore pressure

• Operators adjust their “recipe” for each

hole

• The mud is recycled until it cannot be used

What is drilling mud?

• Some of the many additives may include:

– Bentonite Clay (lubricator/ sealer/ viscosity)

– Barium Sulfate (weight)

– Lime (corrosion)

– Soda Ash (NaCO3 - water conditioner)

– Lignite (viscosity control)

– Loss Circulation Material (sealer)

• ground peanut shells, mica, cellophane, walnut

shells, calcium carbonate, plant fibers, cottonseed

hulls

Types of mud

• Water (WBM) and oil based (OBM)

– WBM uses water as solvent

– OBM uses diesel as solvent

• Have different characteristics for different

purposes in drilling

– Varies between well, region, and operator

• Typically, WBM is used in the vertical portion of

the hole and OBM is used in the curve and

horizontal portions

Contents: WBM

• Typical contents

– Dissolved solids

• Mostly Na, Ba (BAR), Cl

– Minor amounts of Ca and K

– Bentonite (Gel)

• Can add nutrient holding capacity to sandy

soils

– Water (for water portion)

WBM

Contents: OBM • Typical contents

– Petroleum hydrocarbons (TPH)

– Dissolved solids

• Not as high as for WBM

– Calcium carbonate equivalent (CCE)

• From natural bedrock, additives, or bulking agent

– Minerals rich in Ca, Mg, and K

• Depends on bedrock at specific location

OBM

Risks: WBM

• Salinization of soils

– Excess salts: reduces the ability of the

plant to uptake water.

• Remedy: leach out with natural rainfall and

time

• Sodic soils

– excess Na: poor drainage, poor structure

little growth

• Remedy: gypsum + water

Risks: OBM

• TPH toxicity to plants

– Not a long term risk

• TPH degraded into CO2 and H2O through

soil microorganisms

– Optimize conditions: temp, pH, nutrients,

oxygen

– “Bio-Treatment”

– Salinization and Sodicity

• Not as much of a risk as for WBM

Risks: OBM

• BTEX

– Benzene, toluene, ethyl benzene, and xylene

– Benzene is the most water soluble

• Degradation time varies from 10 to 60 days

– Guardian: 44 mg/kg

– DEQ: 0.03 mg/kg

» Threshold assumes soil filled with benzene from

surface to GW and no degradation

• Metabolized by plants into non-harmful compounds

– Experiment to begin: benzene leaching

Risks

• Radioactivity: not likely, but possible

– NORM (naturally occurring radioactive

material)

• Soils range from 0.2 to 4.2 pCi/g in NORM

• OK threshold for application is 30 pCi/g

– Outreach laboratory, Broken Arrow

($150/sample for NORM)

Risks

• Heavy metals (Cu, Zn, As, Pb, etc.)

– Unlikely; will depend on local geology

– Not from additives, but from naturally

occurring geologic formations (rock)

– Metals do not degrade

Rules and Regulations: OK

Corporation Commission • Max 8% slopes

• At least 12 inches of acceptable soil texture

• Must maintain buffer zones (property boundaries,

perennial streams, ponds, water wells, etc.)

• E.C. Less than 4,000 µS and E.S.P. less than 10% in

receiving soil

• Depth to bedrock, 20 inches for WBM, 40 inches for

OBM (may change to 20 inches)

• No water table within top 6’ of Soil Profile

• WBM may be re-spread after 3 years has passed and

Soil test requirements met

• OBM sites can not be re-used for WBM or OBM

– May change to every 3 years

Permissible Loading

• Use Most Limiting Factor Calculations

from OK Corporation Commission

– Must not exceed loading rates

• 6,000 lbs/ac TDS

• 3,500 lbs/ac Cl-

• 40,000 lbs/ac TPH

• 200,000 lbs/ac Dry Weight (For Solids)

Handling of Mud

• OBM is spread only as a solid

– Incorporated

– Must be mixed with bulking agent at a 3 parts agent to 1 part OBM ratio

OBM Solids

Handling of Mud

• WBM is spread both

in liquid and solid

form

Economics

• ~ 50¢ per bbl WBM

• ~ $1.00 per bbl OBM

• Therefore, total cost paid to landowner depends on the well and operator

– Ex. Typical Ellis County well results in $5000 for WBM and $8000 for OBM portion.

• Expect a decrease in yield for a period

– Payout vs. temporary yield decrease: is it worth it?

• Depends on many factors including yield potential

21

Keys for Producers

• The more available acres, the better

• Check the reputation of the spreading contractor

– Call OCC and find out if they have had many problems

• Good contractors will work with you from beginning to

end

• Can NOT use CRP ground

• Ask questions

• If problems do arise, by rule, a bona fide effort must be

made to reestablish vegetation

22

• Early stages: much work to be done

• OBM spreading / handling methods

– Gypsum vs Ag Lime

– Is the 3:1 ratio needed? Too much?

– Other Amendments?

– Is the ‘Death Penalty’ necessary?

– Rainfall timing and TPH degradation rate

– Impact of TPH load and concentration on

degradation rate

Research

Current OBM Research:Treatments

• 3 bulking agents

– Gypsum, caliche, and lime

• 3 ratios of bulking agent:OBM

– 3:1, 1.5:1, and 0 (mud alone)

• Manure amendment applied to mud alone

and gypsum bulked

– Plant available N rate (PAN) and 1.5 PAN

TPH Degradation

rainfall y = 15228e-0.022x

R² = 0.9689

0

5000

10000

15000

20000

25000

0 20 40 60 80 100 120 140 160 180

Soil

TPH

(m

g/kg

)

Time (days)

OBM alone

y = 4780.6e-0.021x R² = 0.8049

0

2000

4000

6000

8000

10000

12000

14000

0 20 40 60 80 100 120 140 160 180

Soil

TPH

(m

g/kg

)

Time (days)

1.5 Gypsum:OBM + PAN Manure

98% of TPH degraded in 170 days Day 170 TPH ranged from 72 to 430 mg kg-1

Forage Yield

c

bc

abc abc

abc

ab abc

abc abc

bc

abc

a a

0

200

400

600

800

1000

1200

1400

1600

1800

Tota

l Fo

rage

Yie

ld (

kg/h

a)

Treatments

Research

• Impact of salts from WBM

on wheat and grass

– Evaluate application timing

and rate

• Lahoma: wheat and grass

• Assessment tool for

predicting safest site

specific WBM application

or time required for salts to

leach

Lahoma Field Day: May 10th

Questions?