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CLEANER. FASTER. SMARTER.


PRESENTATION CONTENT

Current methods Oil & Gas Operators use to manage and minimize waste

(whole fluids and associated cuttings) during a typical land-based drilling

operation.

Drilling fluids selection and region generally determines how these

practices are performed.


TYPES OF OPERATIONAL WASTES

Drilling Fluids

Diesel-Based drilling fluids

Non-aqueous drilling fluids (synthetic oils)

Water-based drilling fluids

Air/Mist operations

Cuttings All wells drilled produce wellbore cuttings

Amount varies depending on depth, hole size and washout

De minimis Wastes Rig floor

Cellar fluids

Fluids adhering to drill pipe during trips

Containment vessels or tank bottoms

Rainwater and rinse water


CURRENT PRACTICES TO MANAGE DRILLED CUTTINGS

Open pits Mainly used for water-based operations, i.e. surface muds, low chloride fluids, low or no oil content in water-based fluids

Regulations determine if this is possible

Collect cuttings with adhered fluids in cuttings boxes (referred to as closed–loop systems) Most common practice used

Insures that all cuttings and adhered drilling fluids are captured for disposal

Requires transfer into movable storage containers which are then sent offsite for disposal

Requires adequate trucking coordination during the course of the well

Requires a large foot-print on location

Adds to overall well costs as opposed to disposal in open pits


CURRENT PRACTICES TO MANAGE DRILLING FLUIDS

Surface Storage Vessels and Frac Tanks Storage tanks vary in size holding as little as 25 barrels or as much as 1000 barrels (42,000 gallons)

Frac tanks hold approximately 500 bbl. of volume

Typically 4-8 Frac tanks are on location at all times to contain drilling fluids and make-up water, drill water

Hoses and valves are used to transfer fluids and help prevent leaks during storage and transfers

Drip pans and buckets are used to catch fluids when disconnecting hoses or valves

Air may be blown thru lines to rid lines of fluids before moving or disconnecting hoses

Pin connectors are used to prevent hoses from working themselves loose during pumping operations

Impermeable liners under storage vessels and frac tanks are used in a lot of operations in-case of spills so that no fluids contact the soil

Sight glasses on vessels help determine levels of fluids

Strapping tanks is done before and after fluid movement

Some vessels use “Floats” or shut-off devices which help control fluid levels


CURRENT PRACTICES TO MANAGE DRILLING FLUIDS

Rig pit system

Optimize pit system usage to fit the volume needed for that particular well; by-pass some pits with the

return flow if volume is not needed

System volume capacity varies among rig companies but standard surface system will hold appr. 1,000 to

1,500 barrels

Most likely source of a spill will occur in surface system during transfer of fluids from storage to surface

system

Each operator and rig combination have specific rules to help avoid any spill occurrences. i.e. some

operators require only transfer of fluids be performed during daylight hours; only qualified personnel can move fluids

and work valves; at least two persons must be present during transfers, etc.

Shale shakers screen selection is critical to minimize drilling fluids adhering to cuttings


CURRENT PRACTICES TO MANAGE DRILLING FLUIDS (CONT.)

Rig pit system

Large volumes of water required to clean surface pits; water can be reused by slightly treating with flocculants

to remove unwanted solids

System volume capacity varies among rig companies but standard surface system will hold appr. 1,000 to 1,500

barrels; reducing workable volume requires less dilution and leads to less overall volume of fluid on location

Working with a lower system volume helps prevent chance of overflowing of pits during transfers or flow

influxes from wellbore ; this may not be possible depending on down hole losses or needing fluid for well

control purposes

Recirculate shaker slide water to rinse cuttings into open top tanks or reserve pits

Use of rig vacuums instead of pressure washing where possible

Limit use of rinse water but in the same notion, recycle it


TYPICAL WASTE MINIMIZATION BY AREA

Texas – West Texas, Panhandle, South

Oklahoma

North Dakota

Northeast – Pa. Ohio, W. Virginia


Diesel-based fluids; Brine based fluids

Closed-loop systems for OBM’s

Lined pits for WBM’s

Methods to limit wastes in this area:

- Include using available production brine as dilution water in the drilling fluids.

- Drill with just brine water if formation pressures allow

WEST TEXAS


TEXAS Panhandle

Diesel-based and freshwater-based fluids



Methods to limit wastes:

Dryers for OBM operations

Dewatering to reuse water


TEXAS South Texas

Largely OBM with some freshwater and brine- based fluids



Some landowners may allow all types of fluids

into land pits


OKLAHOMA Diesel-based and freshwater-based fluids



Methods to reduce wastes:

Reuse water by dewatering

Dryers for OBM Source: Hart’s E&P


NORTH DAKOTA

Diesel-based and brine- based fluids

Closed-loop containment for both

fluid systems


NORTH EASTERN U.S. Synthetic, brine and freshwater-based systems.

Diesel-based fluids can also be used in the region.

Closed-loop systems for ALL systems

Methods used to limit wastes:

Extra measures on locations are taken for containment of fluids and cuttings

Use of EIR (Environmental Impact Reduction) which is the use of chemicals with the least impact to the environs


References http://web.ead.anl.gov/dwm/regs/state/ndakota/index.cfm

Drilling Fluids Processing Handbook; ASME. 2005

http://web.ead.anl.gov/dwm/regs/state/ndakota/index.cfm





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