Abstract Based on recent studies of Barnett and Woodford gas shales in Texas and Oklahoma, a systematic characterization workflow has been developed that incorporates lithostratigraphy and sequence stratigraphy, geochemistry, petrophysics, geomechanics, well log, and three-dimensional (3-D) seismic analysis. The workflow encompasses a variety of analytical techniques at a variety of geologic scales. It is designed as an aid in identifying the potentially best reservoir, source, and seal facies for targeted horizontal drilling. Not all of the techniques discussed in this chapter have yet been perfected, and cautionary notes are provided where appropriate. Rock characterization includes (1) lithofacies identification from core based on fabric and mineralogic analyses (and chemical if possible); (2) scanning electron microscopy to identify nanofabric and microfabric, potential gas migration pathways, and porosity types/distribution; (3) determination of lithofacies stacking patterns; (4) geochemical analysis for source rock potential and for paleoenvironmental indicators; and (5) geomechanical properties for determining the fracture potential of lithofacies. Well-log characterization includes (1) core-to-log calibration that is particularly critical with these finely laminated rocks; (2) calibration of lithofacies and lithofacies stacking patterns to well-log motifs (referred to as gamma-ray patterns or GRPs in this chapter); (3) identification and regional to local mapping of lithofacies and GRPs from uncored vertical wells; (4) relating lithofacies to petrophysical, geochemical, and geomechanical properties and mapping these properties. Three-dimensional seismic characterization includes (1) structural and stratigraphic mapping using seismic attributes, (2) calibrating seismic characteristics to lithofacies and GRPs for seismic mapping purposes, and (3) determining and mapping petrophysical properties using seismic inversion modeling. Integrating these techniques into a 3-D geocellular model allows for documenting and understanding the fine-scale stratigraphy of shales and provides an aid to improved horizontal well placement. Although the workflow presented in this chapter was developed using only two productive gas shales, we consider it to be more generically applicable.

Abstract A method is described for reservoir characterization in fine-grained and thinly bedded shales based on a probabilistic clustering procedure (PCP) of well logs followed by a forward modeling procedure that results in the calculation of profiles for porosity, water saturation (Sw), and permeability. The credibility of results relies on calibration using porosity, permeability, and mineralogy analyses of core samples. Complementary analysis using a nuclear spectroscopy log, if available, can add confidence to the results. Kerogen needs to be included during the forward modeling because it is a matrix component of the bulk rock and the matrix grain density (GD) can be significantly affected by kerogen. Kerogen profiles can be estimated if kerogen core analyses are included in the PCP. In addition, a total organic carbon (TOC) profile, which is needed to determine the amount of adsorbed gas, can be estimated based on core analyses of TOC. The relationships between TOC and kerogen, including a discussion of Rock-Eval pyrolysis, are outlined. The estimation of free gas gross pay in gas shales is fraught with difficulty because of the vagaries of estimating porosity and Sw. Although not realistic in terms of gross storage capacity, the use of the combination of total porosity (TPOR) and total water saturation (Swt) gives the same pay as the combination of effective porosity (EPOR) and effective water saturation (Swe). However, the combination of EPOR and Swt is ill-construed and results in underestimation of gross pay. The estimation of adsorbed gas in gas shales relies on a methodology and equations adopted from the coalbed methane industry. The workflow is easily implemented, but the credibility of results hinges on the assumption that the adopted methodology and equations are valid for gas shales, and on having sufficient and proper laboratory-derived gas adsorption isotherm measurements to represent the TOC heterogeneity of the reservoir. An example is given using analysis of a cored well from the Upper Jurassic Haynesville Shale of northwestern Louisiana and northeastern Texas. The analysis generated profiles for TPOR and EPOR, Swt and Swe, permeability, and net feet of pay.

Abstract These notes have been written to supply supporting material for a “short course” introduction to environmental hydrogeology. The assumption is that most people who take the short course (or purchase the notes without taking the short course) will be geologists, although the information could be useful to engineers or other scientists who desire an introduction to environmental consulting in general, or hydrogeology in particular. The notes, and course, are an introduction – a partial survey - of some aspects of environmental geology, with particular reference to subsurface hydrogeology and remediation of sites contaminated with petroleum hydrocarbons. No claim of completeness is made. Regulatory programs vary from state to state. The regulatory framework used in the state of New York is sometimes given as an example. The reader should be aware that rules and procedures may differ in other states.

Abstract Pollution is a matter of observation, impression, and definition. Although arguments exist about the amounts of pollution in the air and in the ground and the effects of various pollutants on the ecosystem, including Homo sapiens, most people would agree that the world's population has increased in a dramatic fashion in the last 150 years, that people produce waste, and that waste sometimes accumulates to the point of being harmful, either aesthetically or physically, or both. Pollution can be defined as contamination of the environment (ecosystem) such that the individual components in the ecosystem are not capable of serving their intended function. For example, we can discharge contaminates into a river to a point where fish can no longer live. Similarly, anthropological emissions entering the atmosphere can make air unhealthy to breathe. Sufficient citizen complaints result in Congress adopting statutes designed to temper or remove the pollution problem. Unfortunately, Congress sometimes looks for a political rather than a scientific solution to the pollution problem. Accordingly, many statutes are vague and, as with the Clean Air Act, include exemptions designed to avoid economically harming the financially powerful sector of the constituency. The EPA (Environmental Protection Agency) interprets a statute by writing federal regulations. Implementation of federal regulations can vary among states depending on differing economic and political pressures within the states. For example, the Petroleum Extraction Industry is prohibited by "permit" from discharging any polluted waters into the Waters of the U.S. from any onshore facilities located in Louisiana,New Mexico,Oklahoma

Abstract An environmental assessment is done to determine whether a property has a current environmental liability or is likely to have an environmental liability in the future. There are different kinds of assessments and they can be done at the request of different entities (current owner, prospective buyer, bank or lending institution, real estate agent, state or municipal regulator, attorney, etc.). They are commonly required by the person or entity likely to incur liability should the property change ownership. The terminology may vary from state to state. The following descriptions are taken from Ouellette, R. and Maestri, B. ("The Process and Cost of Environmental Audits", Hazmat World, October 1989, p. 57-61). environmental inventory - identifies what quantities of different materials are present environmental inspection - a walk-through to identify materials and determine how they are managed; might include rudimentary sampling environmental audit - broader review to determine suspected, actual, and potential liabilities; basic purpose is to reduce environmental and financial uncertainties for all parties involved in a transaction; types: 1. inspection: term commonly used to connote asbestos hazard "management"; 2. compliance audit: a one-to-one comparison between regulations and a facility's performance; 3. risk assessment: includes an evaluation of the impact on health & safety from potential threats; 4. environmental impairment liability risk assessment: insurance-oriented; for obtaining adequate insurance coverage; environmental assessment - more in-depth review than audit; incorporates health and safety impacts.

Abstract The following is taken from a 1985 EPA publication (EPA/530-SW-85-007, May 1985). The Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA) have been concerned with the potential health hazards associated with exposure to asbestos since the early 1970s. The concern is based on medical evidence relating to exposure of airborne asbestos by asbestos workers and their families to various types of cancer as well as noncancerous respiratory diseases……… Description of Asbestos: Asbestos is a naturally occurring family of fibrous mineral substance. The typical size of asbestos fibers………is 0.1 to 10 µm in length……… when disturbed, asbestos fibers may become suspended in the air for many hours, thus increasing the extent of asbestos exposure for individuals within the area. EPA regulations identify the following types of asbestos: chrysotile, amosite, crocidolite, anthophyllite, actinolite, and tremolite. Approximately 95 percent of all asbestos used in commercial products is chrysotile………asbestos fibers have been mixed with various types of binding materials to create an estimated 3,000 different commercial products. Asbestos has been used in brake linings, floor tile, sealants, plastics, cement pipe, cement sheet, paper products, textile products, and insulation. The amount of asbestos contained in these products varies significantly, from 1 to 100 percent, depending on the particular use. The potential of an asbestos-containing product to release fibers is dependent upon its degree of friability. Friability means that the material can be crumbled with hand pressure and, therefore, is likely to emit fibers. The fibrous or fluffy spray-applied asbestos materials

Abstract A basic understanding of hydrology is central to the understanding of surface water degradation. A few basic facts concerning surface water are: • Surface water originates from meteoric water (e.g., rain and snow). • The dissolved chemistry of meteoric water will be a function of the chemistry of the air through which the water moves. • Surface water has a natural dissolved and particulate chemistry which varies with location and depends on the geology and biology of the terrain over which or through which the water has flowed. • Surface water resources are not infinite. • Surface water resources are not equally distributed either in a geographic sense or in a demographic sense. • Surface water can be used and reused, but its composition (quality) at any given point will be a function of its most recent history. • The ultimate endpoint of most surface water "flow" is the oceans. Therefore, the oceans are the ultimate repository of contaminants (unless the contaminants are removed from solution prior to reaching the ocean).

Abstract Organic compounds that are composed mostly of carbon and hydrogen atoms are called hydrocarbons (HC). Classification of compounds, both natural and synthetic, is on the basis of chemistry and molecular structure. 5.1.1 Classification HC compounds are commonly classified as aliphatic or aromatic (Figure 5.1). The aliphatics are subdivided as follows: Aliphatic Alkane (= paraffin = chain) Unbranched (= normal = n-paraffin = n-alkane) Branched Naphthene (= ring = cycloparaffin) Alkene Alkyne Alkanes are unbranched or branched chains of C atoms each surrounded by four other atoms, generally H and other C atoms. The general formula is (C n H 2n+2 ). If the carbon atoms are all approximately in a "line", the structure is said to be unbranched or normal or n-paraffin or n-alkane If one or more carbon atoms are located at an angle to the main "line" of carbon atoms, the structure is said to be branched or isoparaffin.

Abstract Much of the information in sections 6.1 and 6.2 is taken from Cheremisinoff et al. (1987). Of the estimated two to five million underground storage tanks (USTs) that exist in the United States, most are simple single-wall tanks made of steel. The major cause of leaks is corrosion of the steel, although improperly fitted or failed piping valves can also result in leaks. Corrosion results from the existence of an electrical current that permits an oxidation-reduction reaction to occur. Oxidation of iron to iron oxide (rust) occurs at the anode of the electrical cell, which can be an imperfection (e.g., scratch, etc.) in the wall of the tank or some other difference between that part of the tank and another part of the tank or piping that serves as the cathode (cf. Figure 6.1). Alternatives to non-protected steel-walled tanks include (cf. Figure 6.2): 1) protecting a steel tank from corrosion using cathodic protection; 2) coating a steel tank with fiberglass; 3) lining a steel tank with a corrosion resistant liner; 4) using a double-walled tank with no monitoring system; i.e., a steel inner tank with a fiberglass-coated outer tank; 5) using a double-walled tank with a monitoring system; i.e., a steel inner tank and a fiberglass-coated outer tank, with a HC vapor or liquid sensing probe inserted between the two walls; and 6) using a fiberglass tank. The lifetime of unprotected steel tanks (before they begin to leak) varies greatly. Factors that accelerate corrosion are high moisture content in

Abstract The most common and most useful method for determining whether or not groundwater is contaminated is to install permanent groundwater monitoring wells from which groundwater samples can be collected. This is called a "groundwater study". The goals, or steps, typically are to: 1. install and develop three or more monitoring wells at the site; 2. sample the groundwater in the wells; 3. have the samples analyzed for likely contaminants; 4. evaluate the analytical results and plot the distribution of contamination on a map; 5. determine the direction of groundwater flow by surveying the site to establishing the location and elevation of the measuring point on each well relative to a benchmark, and then measuring the depth to groundwater in each well; 6. use the results of steps 4 and 5 to determine the scope of contamination, the likely source of contamination, and whether or not additional monitoring wells are needed; and 7. devise an appropriate remedial strategy

Abstract In the oil and gas exploration and production industry, one learns that oil floats on water, that there is an "oil-water" contact, and that for all practical purposes in oil extraction, one is after the oil that floats on the water. Looking up the solubility of a typical hydrocarbon compound found in gasoline, such as toluene, in a CRC Handbook of Chemistry and Physics, results in the finding that the solubility of toluene in water is "i"; that is, it is insoluble. In fact, toluene, like many "insoluble" hydrocarbons, is very slightly soluble in water, and the amount that will dissolve is much more that one would like to have in drinking water. The solubility of several hydrocarbons was given in Table 5.4. The solubility is much greater for these compounds than the amounts permitted in water (e.g., potable water) by regulations. Because of its carcinogenic affect, benzene is often "keyed" upon at sites where gasoline, for instance, has been spilled. The permitted level of benzene in drinking water is currently ≤ 0.7 ppb in NYS, because that is the approximate detection limit.

Abstract Remediation means cleanup. Methods of soil remediation include the following (Figure 9.1): 1. Excavation followed by disposal in a landfill 2. In situ methods a. Soil venting b. Bioremediation 3. Excavation followed by onsite treatment a. Soil venting of soil pile b. Bioenhanced soil farming c. Thermal treatment (e.g., via rotary kiln) 9.1.1 Excavation Followed by Disposal in a Landfill Excavation of soil followed by disposal in a permitted landfill is used as a method of remediation when the soils are readily accessible for excavation, the contaminants are such that the landfill will accept the soil, and the cost is "right". This method remediates the site, but does not remediate the soil. The contamination is simply transferred to the landfill. Cost is usually calculated on a per ton basis. The trucks are loaded with soil and weighed, then weighed after dumping the load. Costs (excavation, loading, transportation, and tipping fee) for non-hazardous petroleum-contaminated soils might vary from $50. to $80. per ton. Using a conversion factor of 1.3 tons per cubic yard and a cost of $65./ton, an 8-foot deep excavation with an area of 20 feet on a side would be 118.5 yards. The soil would weigh about 154 tons, and the disposal cost would be about $10,000. Additional costs would probably include the costs of soil analyses (the landfill will want to know the contaminant content of the soil before agreeing to accept the soil).

Abstract Although water may contain excess inorganic compounds of many kinds, heavy metals are one of the more common problems. Remediation (removal) of the compounds is commonly done by pH control. That is, the pH is raised to a level at which the metal is insoluble. Then, the precipitated metal is made to flocculate so that it will settle out of the water column. After the metal settles, the water can then be brought back to a normal pH by adding an acid. Details of the above processes are beyond the scope of this course and text. A review of the above process, plus other processes for removing metals (ion exchange, reverse osmosis, electrodialysis, and distillation) are given in Nyer (1985). The thermodynamic equilibrium basis for the solubility of metals (and nonmetals) as a function of pH and Eh is reviewed in Fetter (1993). A more complete description is given in Garrels and Christ (1965). Figures 10.1 and 10.2 (adapted from Garrels and Christ, 1965, Figs. 7.5d and 7.5e) are examples of how the stability field of an inorganic species, iron in this case, can be described using Eh-pH plots. Figure 10.1 shows that the maximum amount (activity) of dissolved Fe +2 that can exist in solution decreases both with increasing Eh and increasing pH. Figure 10.2 shows that the activity of dissolved Fe +3 that can exist in solution is unaffected by Eh (in the hematite + water field) but decreases with increasing pH.Comparison of the two figures shows that Fe +3

Abstract The purpose of this chapter is to illustrate how modeling programs can be used to interpret groundwater movement. In addition, support models are presented, the purpose of which is to help the geologist make essential economic decisions and to communicate effectively with regulatory agencies. An essential part of any report is its presentation. For this reason, programs that help in report preparation are also presented. These include contouring capabilities, graphing programs, and a program designed specifically for editing the huge matrices of numbers that are typically generated by the modeler. The programs that are discussed are mostly in the public domain, or are relatively inexpensive to purchase, and all are sized to be used on standard IBM-clone PC.

Abstract These notes provide a general introduction of clays for the uninitiated, plus a review of traditional and more recent concepts for those who already know something about clays. The concept of fundamental illite particles and the phenomen of interparticle diffraction, relatively new concepts that are reshaping the manner of visualizing mixed-layer clays, are discussed in some detail. A discussion of shaly-sand log analysis, from a clay mineralogy perspective, is included. Isotope geology is discussed because of its potential for permitting a better understanding of temperatures and timing of diagenesis.