Optimization Approach to Produced Water Management

1. Optimization Approach to Produced Water Management Dan Tormey, Ph.D., P.G.Cardno Ltd.

2. What is the Produced Water “Problem”? • Large volumes of water produced by oil and gas • Typically saline • May contain other contaminants • Volumes typically greater than can be accommodated by injection • Source of Public Concern

3. Waste or Resource? United States ALL produced water considered a waste Prohibition on surface discharge unless benefits to wildlife or agriculture can be demonstrated Australia Most states define produced water as a waste Queensland redefinition: Beneficial if “no harm” can be demonstrated

4. A New Source of Water Treated produced water used for: USA: • Crop irrigation • Stock watering • Groundwater recharge • Wildlife habitat support • Australia: • Crop irrigation • Golf course irrigation • Stock watering • Industrial uses • Stream discharge • Ecuador, Columbia, Indonesia: • Encouraging beneficial reuse as a component of the social license to operate Displaces demand on public potable water supplies

5. Produced waters not created equal Variable: • Salinities • Temperatures • Other compounds • Volume and change over time • Beneficial uses intensely site-specific • Agriculture • Industrial • Ornamental plants NO ONE SOLUTION

6. How to Optimize for a Site-Specific Solution? FOUR STEPS • Understand the source • Understand the potential use • Understand the available treatment technologies • Have backup plans

7. Step 1: Understand the Source • How much water produced over time? • What is the quality over time? • What is the temperature over time? • How much can be injected without undermining resource recovery?

8. Step 2: Understand the Beneficial Uses Survey of local opportunities • Local water users/needs? • Ocean outfall? • Stream discharge? • Geothermal? • Evaluate compatibilities • Water quality requirements • Compatibility of produced water (treated or untreated) with the use

9. Step 3: Understand Treatment Technologies Untreated • Compatibility and reliability assessments Injection • Compatibility assessment • Affect on other groundwater resources Variety of Treatment Options • Ion exchange • Membranes (including RO) • Mechanical vapor recompression • Air stripping • Precipitation • Dilution

10. OPTIMIZATION • Balance cost and reliability • Create a menu of uses that • Support full time operation • Consider potential loss of some uses • Understand changes over time • Create backup plans to enhance system reliability • Untreated • - Aquifer Injection • - Industrial Uses • Limited Ag • Diluted/Moderately Treated • - Limited Agricultural • - Private Use • Fully Treated • - Unrestricted Agricultural Use • - Discharge to surface waters

11. California Example • Optimization Model indicated that: • Reverse Osmosis Treatment was needed to sell or discharge the produced water • Brine could be reinjected to producing formation • Receiving water and upland studies • Designed and completed entire approval process • Coordinate with equipment vendors for performance standards

12. Australia Example Optimization Model used to determine menu of Beneficial Reuses No Treatment: • Stock watering • Industrial washdown • Dilution/discharge • Treated: • Irrigation • Stream discharge • Limited opportunity for injection • Mechanical Vapor Recompression selected for treatment

13. Ecuador/Columbia/Indonesia • Large volumes of produced water with limited beneficial reuse • Growing concern over Social License to Operate • Fact-Finding and Benchmarking • Optimization Model applied over a national territory • Establish stakeholder relationships • Opportunity to learn from USA and Australia experience

14. Summary • A new view of produced water: New resource, not a waste • Regulatory hurdles easing as the beneficial uses are demonstrated • Regulatory uncertainty and urgent need together create a confusing marketplace • Local solutions needed • Optimization approach to balancing source, end users, and treatment technologies