ENVIRONMENTAL ISSUES AFFECTING COALBED METHANE GAS DEVELOPMENT IN THE APPALACHIAN BASIN

• Jurisdiction: United States

Coalbed Gas Development
(Apr 1992)
CHAPTER 8A
ENVIRONMENTAL ISSUES AFFECTING COALBED METHANE GAS DEVELOPMENT IN THE APPALACHIAN BASIN
Isaias Ortiz
United Energy Development Consultants, Inc. (UEDC)
Pittsburgh, Pennsylvania

TABLE OF CONTENTS

SYNOPSIS

Page

ABSTRACT

BACKGROUND

AirToxics

Produced Water Management

Management of Associated Wastes

Naturally Occurring Radioactive Materials (NORM)

Shallow Subsurface Contamination

Deep Subsurface Contamination

SUMMARY

REVIEW OF PRODUCED WATER MANAGEMENT STRATEGIES

Summary of Treatment Options

OVERVIEW OF CRITICAL REGULATORY AND TECHNICAL FACTORS

The Resource Conservation and Recovery Act (RCRA)

The Safe Drinking Water Act (SWDA)

The Clean Water Act (CWA)

State Environmental Performance Regulations

WASTE MANAGEMENT PRACTICES

Deepwell Injection

Black Warrior Basin

San Juan Basin

Appalachian Basin

Treatment Followed By Surface Discharge

Black Warrior Basin

San Juan Basin

Appalachian Basin

Land Application/Surface Evaporation

Black Warrior Basin

San Juan Basin

Appalachian Basin

Publicly Owned Treatment Works

Co-Disposal In Mines

Wetlands Applications

Offsite Commercial Disposal

TREATMENT COSTS

REFERENCES

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ABSTRACT¹

The management of produced water from natural gas production particularly in conjunction with coalbed methane poses a unique set of technical problems as well as regulatory issues. The nature of these problems are dictated by the characteristics of the produced water, the treatment requirements of the potential management options, and the regional or site-specific factors associated with the production operations.

The technical and environmental issues associated with the produced water management strategies for two areas of the United States, Southeastern United States (Black Warrior Basin) and North/Central Appalachian Basins, are reviewed in this text, but also are compared to other areas such as the San Juan Basin. (The Black Warrior Basin in this text is considered a part of the Appalachian Basin.) The issues that are common to all of these geographical areas as well as those that are unique to a specific area are identified.

Regulatory issues impacting produced waters are summarized and their relative impact on current operations is discussed.

BACKGROUND

The key environmental issues associated with the production of natural gas have been described in several reports which have integrated the results of the Gas Research Institute (GRI), the U.S. EPA and the American Petroleum Institute. The framework that was established for this examination segregates the issues into four major categories: (1) Fugitive Emissions/Offgas Management, (2) Surface Management of Water and Wastes, (3) Management of Shallow Subsurface Contamination (Zero to 300 feet), and (4) Management of Deep Subsurface Contamination (Greater than 300 feet). Within each of these categories, the following list of specific issues were identified:

— Air Toxics (Methane emissions)

— Produced Water Management

— Management of Associated Wastes

— Management of Naturally Occurring Radioactive Materials (NORM)

— Shallow Subsurface Contamination

— Deep Subsurface Contamination

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A brief discussion of each of these areas is provided in the remainder of this section. This paper will focus on water management issues.

Air Toxics

The U.S. EPA has already targeted air emission sources within the gas industry for regulation. In addition, the recent amendments to the Clean Air Act have specified total emission rates for a large number of toxic chemicals, both singly (10 tons/day) and as a total (25 tons/day). Several states, such as Louisiana and Texas, are considering emission limitations for benzene on the order of 10's and 100's of pounds per day. These regulatory shifts have made benzene, specifically, and air toxics, in general, a primary environmental issue for the industry.

More recently, the "greenhouse effect" has had a dramatic impact on the awarness of CO₂ and methane gas emissions. This has particularly impacted high sulfur steaming coals and their uses in electric power generation.

Methane emissions are particularly high in the northeast, associated with long-wall mining. Pending legislation directed at encouraging coal operators to capture this gas, in lieu of venting, can add substantial gas reserves to the domestic reserve base.

Produced Water Management

Large volumes of produced waters are generated, particularly, in association with coalbed methane production, which may contain a very high salt content. In addition, many of these waters also contain trace constituents which originate from the formation itself or from the addition of production additives during their surface or sub-surface treatment. These trace constituents are and/or may be considered as toxic or hazardous compounds. As such, there is a possibility that future regulations may require the removal of some of these constituents, such as oil and grease, heavy metals and selected additives, prior to final disposal.

EPA's RCRA regulations contain a so-called "mixture rule" that provides that the commingling of any listed hazardous waste with a nonhazardous waste stream renders the entire mixture a hazardous waste. The intent of this rule is to prevent avoidance of hazardous waste regulations through dilution. These requirements could represent a substantial economic burden to the industry.

Management of Associated Wastes

These wastes represent a cross section of solids and liquids which are associated with the production of natural gas and which, as a whole, are currently exempt from RCRA. Included among these wastes, are a variety of separation waters which are intermittently produced. However, the U.S. EPA is now considering them for regulation. This is especially true for those wastes which fail one of the RCRA hazardous waste characteristic tests. This shift in the regulations has the potential to dramatically increase the costs of managing this specific category of wastes.

Naturally Occurring Radioactive Materials (NORM)

The presence of natural radioactivity in gas formations and ultimately, in the production and distribution systems, represents a substantial issue for the industry. For example, their presence downstream from the formation could lead to the classification of the industry wastes as "mixed wastes" which would dramatically increase the cost of any treatment

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strategy since "mixed waste" disposal facilities are practically nonexistent. Furthermore, their presence in produced water will most likely preclude many of the surface management options that are currently in use.

Shallow Subsurface Contamination

There is often surface and shallow subsurface contamination at natural gas production, processing, and storage facilities that reflect the full range of chemicals that are present both in the formation and in the surface treatment processes that are used to process the production fluids. The treatment of these soils, sludge, and groundwater represents a potential liability to the gas industry and is complicated by the fact that may of the sites may contain high levels of salt. The presence of the salt (particularly those with heavy metals) complicates the application of conventional treatment technologies to the wastes and will no doubt increase the cost of their management.

Deep Subsurface Contamination

Deep subsurface contamination is associated with the failure of injection wells during operation and/or the impacts of their improper closure or abandonment. Since these problems often manifest themselves at substantial depths, their management presents a difficult problem that will likely be very costly to address with any form of treatment or containment.

SUMMARY

The coalbed methane gas industry is economically dependent on the ability to dispose of the large volumes of the associated water which are produced at low costs, particularly considering today's economic environment, gas demand and pricing. If environmental regulations are unduly interpreted by regulators or stiffened any further, the potential impact of the costs of treatment on the profitability to this segment of the natural gas industry could be significant.

This paper will focus on key issues by examining the management of produced waters from the coalbed methane industry in the East. This focus was driven by the fact that coalbed methane represents a future gas reserve of large potential to the industry that has been somewhat slow in developing due to overall economic tax-credit considerations, ownership issues and environmental-regulatory hurdles. The cost of produced water treatment represents a significant contributing factor to the economic viability of this portion of the gas industry.

First several key questions must be answered. Some of the more important of these questions are:

What impact do environmental regulations have on operations?

How is the produced water currently managed in the coalbed methane industry and what does it cost?;

Can the current treatment costs be reduced through changes in the current management practices?;

Are there new technology applications which can provide more cost-effective treatment than the current practices?

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The gas industry has to face these issues daily in order to make sound business decisions which will protect the environment while maintaining an economically viable gas production operation. The industry also has to examine the cost impact of current as well as future environmental regulations. These issues are harder to define, yet easy to speculate on with much discontent.

REVIEW OF PRODUCED WATER MANAGEMENT STRATEGIES

Summary of Treatment Options

Table 1 provides a summary of the produced water management options that were practiced in either the Southern (Black Warrior), Northern, or Central Appalachian Basins or...