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Collaborating Authors
U.S. EPA
ABSTRACT Time-lapse joint inversion of geophysical data is required to image the evolution of oil reservoirs during production and enhanced oil recovery, sequestration, geothermal fields during production, and to monitor the evolution of contaminant plumes. Joint inversion schemes reduce space-related artifacts in filtering out noise that is spatially uncorrelated, and time-lapse inversion algorithms reduce time-related artifacts in filtering out noise that is uncorrelated over time. There are several approaches that are possible to perform the joint inverse problem. In this work, we investigate the structural crossgradient (SCG) joint inversion approach and the crosspetrophysical (CP) approach, which are appropriate for time-lapse problems. In the first case, the inversion scheme looks for models with structural similarities. In the second case, we use a direct relationship between the geophysical parameters. Time-lapse inversion is performed with an actively time-constrained (ATC) approach. In this approach, the subsurface is defined as a space-time model. All the snapshots are inverted together assuming a regularization of the sequence of snapshots over time. First, we showed the advantage of combining the SCG or CP inversion approaches and the ATC inversion by using a synthetic problem corresponding to crosshole seismic and DC-resistivity data and piecewise constant resistivity and seismic velocity distributions. We also showed that the combined SCG/ATC approach reduces the presence of artifacts with respect to individual inversion of the resistivity and seismic data sets, as well as with respect to the joint inversion of both data sets at each time step. We also performed a synthetic study using a secondary oil recovery problem. The combined CP/ATC approach was successful in retrieving the position of the oil/water encroachment front.
- Europe > Norway > North Sea > Central North Sea > South Viking Graben > PL 046 > Block 15/9 > Sleipner Field > Draupne Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > South Viking Graben > PL 046 > Block 15/8 > Sleipner Field > Draupne Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > South Viking Graben > PL 046 > Block 15/6 > Sleipner Field > Draupne Formation (0.99)
ABSTRACT Corrosion inhibitors for drinking water use must address multiple objectives: control of lead, copper, and undersiable aesthetic or disinfection problems. Only inhibitors based on families of orthophosphate, polyphosphate and silicate chemicals are permitted because of toxicity concerns, and they must meet certain standards for indirect additives to drinking water. Successful application of corrosion inhibitors for achieving regulatory objectives requires careful consideration of the background water chemistry, particularly pH and DIC. Inhibitor performance is extremely dependent upon dosage and pH, and frequently pH must be adjusted with inhibitor addition. Many issues remain to be resolved about the mechanisms of corrosion inhibition afforded. To facilitate better prediction of performance more fundamental research is needed under realistic drinking water dosage, background water quality, and scale aging conditions. INTRODUCTION In drinking water treatment applications, the term corrosion inhibitor can assume a wide variety of meanings. Part of the confusion stems from common historical usage, often developed before a clear understanding of the true nature and mechanism of inhibition had evolved. Also, there has often been a confusion between true corrosion inhibition and masking of aesthetic problems such as red or black water through a variety of dispersant and sequestrant properties. Thus, a chemical may be called a corrosion inhibitor by many utility staff or water treatment practitioners, even though it may actually increase the rate of corrosion, or otherwise change the corrosion reaction so that there appears to be no or reduced corrosion. Certain natural substances, particularly some high-molecular weight compounds (such as humic and fulvic materials), have been shown to provide an enhancement of passivation film formation in several water supplies.3?4 The usage of the term inhibitor in this paper will follow that of a variety of international researchers, and is intended to apply to chemicals that are intentionally dosed in small quantities to significantly reduce the electrochemical corrosion rate, the metal corrosion byproduct release, or both. Unlike industrial process systems, the classes of compounds allowable for use in drinking water is extremely constrained by health concerns in two ways. First, there is the concern about the heath effects of the dominant chemical constituent, such as polyphosphate, orthophosphate or sodium silicate. Thus, compounds based on chromates, molybdates, and similar materials acceptable for industrial use cannot be applied to drinking water. Only compounds made of individual kinds or combinations of orthophosphate, polyphosphate and silicate, are permissible inhibitor materials. Second, there is a concern about the purity of the chemicals, and inadvertent drinking water additives such as lead, cadmium, zinc, etc. Therefore, all treatment chemicals used in the United States must meet particular quality standards and be tested in accordance with the ANSI/NSF Standard 60, and must be considered food grade or be NSF-approved (National Sanitation Foundation International). 3 Similar or even more stringent standards apply in Europe. 3 Additional specifications and standards for bulk feed chemical composition and testing are covered by a series of American Water Works Association (AWWA) standards. 3 Some formulation components common in industrial inhibitors, such as nitrite or bisulfite, are not used in drinking water formulations. Additionally, typical dosages of phosphate-based inhibitors are much lower than would be used in such applications as cooling towers or boilers. Particular concern over lead toxicity and lead
- North America > United States > Texas (0.28)
- North America > United States > Ohio (0.28)
- North America > United States > Colorado > Denver County > Denver (0.15)
- Water & Waste Management > Water Management > Water Supplies & Services (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Completion > Well Integrity > Subsurface corrosion (tubing, casing, completion equipment, conductor) (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Corrosion inhibition and management (including H2S and CO2) (1.00)
- (2 more...)
Abstract An operator of a Class II injection well (i.e., used in conjunction with oil and gas production) is required to perform a mechanical integrity test (MIT) at least once every five years. We studied the rates of and reasons for failure of over 10,000 scheduled MITs, for a variety of completion types, in the States of Louisiana, Michigan, Nebraska, and Pennsylvania, over two 5-year MIT cycles. The failure rate for State/cycle combinations ranged from 3 percent to about 12 percent for scheduled MITs. However, we found that the actual rate of well failure was at least 50 percent greater, considering the rate of reported well failures in service and evidence of operators pre-testing and repairing wells prior to the scheduled MIT. We found that the primary reason for MIT failure was casing failure (45 percent to 85 percent of State failures), compared to tubing, packer, or wellhead failures. Over 26 percent of wells with casing failures were plugged within 60 days of the test, which suggests problems of a more serious nature. For about 22 percent of the wells with casing failures, the failure involved the only layer of protection, and it allowed waste to be injected outside the wellbore. Background The primary purpose of the Underground Injection Control (UIC) program is to protect Underground Sources of Drinking Water (USDWS) from contamination from injection wells. One of the most important provisions of the UIC program is the requirement that an operator routinely test the mechanical integrity (MI) of his injection well. Mechanical integrity means both the absence of leaks in the tubular goods (internal MI) and the absence of flow from the injection zone through channels in the cement (external MI). Operators of Class II injection wells (those used in conjunction with oil and gas production) are required to perform a mechanical integrity test (MIT) at least once every five years. Internal MI may be established by a pressure test of the tubing/casing annulus if the well has a packer. If not, an MIT may require that a retrievable plug be run in casing to allow a pressure test, or that a water-in-annulus or other test be performed to evaluate Ml. In most State programs, external MI is established only once by the submission of cementing records as evidence of a proper cement job, but may also be tested directly in the field using wireline methods. The results of the MIT must be submitted to the Director of the program for that State, whether the EPA Regional Administrator in States where the EPA has Direct Implementation (DI) authority, or to the UIC Director of a State program where the State has been granted primacy. If the well passes the MI test, it is authorized to continue operation. If the well fails, it is usually shut in until it is repaired and successfully re-tested. P. 287
- North America > United States > Louisiana (0.37)
- North America > United States > Texas (0.28)
- North America > United States > Pennsylvania (0.26)
- (2 more...)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.70)
- North America > United States > South Dakota > Williston Basin (0.99)
- North America > United States > North Dakota > Williston Basin (0.99)
- North America > United States > Montana > Williston Basin (0.99)
Abstract The Environmental Protection Agency (EPA) is proposing amendments to its Underground Injection Control (UIC) program regulations (40 CFR parts 144 and 146) as they pertain to Class II (oil and gas-related) wells. The proposed amendments revise current provisions relating to construction standards and apply the "area of review" and corrective action requirements to previously exempt wells "authorized by rule." The proposed modifications build upon recommendations made by a Federally-chartered Advisory Committee pursuant to the findings of an internal Mid-Course Evaluation effort and a General Accounting Office Report. Under the provisions of Section 1425 of the Safe Drinking Water Act (SDWA), these amended regulations would not need to be adopted verbatim by the States; however, EPA will require that "primacy" States demonstrate that their programs are still effective in light of these new Federal requirements. Background EPA has primary enforcement responsibility to administer the Underground Injection Control (UIC) program under provisions set forth in the Safe Drinking Water Act (SDWA). EPA has been involved in a series of efforts over the last five years which led to a re-examination of the regulations governing Class II injection wells. These regulations are directly applicable in States where EPA implements the program and form the basis for judging whether delegated ("primacy") State programs are effective in protecting underground sources of drinking water (USDWs). EPA believes that there are several significant issues that warrant amendments to the current regulations. P. 269
- Law > Environmental Law (1.00)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Abstract In a continuing effort to encourage improvements in the management of exploration and production (E and P) wastes, the Office of Solid Waste (OSW) of the U.S. Environmental Protection Agency (EPA) is identifying practices and technologies that may contribute to pollution prevention and waste minimization when applied to E and P operations. The sources of this information include trade literature, product literature, and patents. Once identified, details of these practices and technologies may be compiled in a database where the information may be easily accessed and ultimately used in the development of outreach materials for industry. Several notable practices and technologies identified to date are discussed in this paper along with results of field trials where available. Although many have already been described in the literature, the intent of the authors is to present a brief overview of selected pollution prevention and waste minimization concepts in order to stimulate further investigation and discussion. Introduction A discussion of pollution prevention and waste minimization should first be prefaced with definitions of the two terms. EPA defines "pollution prevention" as "efforts to reduce or prevent pollution at the source through cost-effective changes in production, operation, and raw material use". Waste minimization includes pollution prevention, or source reduction through changes in operations and product substitution, and the following types of recycling:beneficial use/reuse, and reclamation. Waste minimization does not include recycling activities whose use constitute disposal and burning for energy recovery. Although certain types of recycling are not interpreted as waste minimization, operators are encouraged to consider these and other innovative pollution prevention options when source reduction is not feasible. One of the motivating factors for compiling E and P pollution prevention and waste minimization information stems from the 1980 amendments to the Resource Conservation and Recovery Act (RCRA). In the 1980 amendments Congress directed EPA to develop a research, development, and demonstration (RD and D) plan outlining various topics that federal and state governments and/or industry could pursue. In a regulatory determination published in July 1988, EPA stated that the RD and D plan should include, among other topics: alternative waste management technologies, waste minimization techniques, materials substitution, and recycling and reuse. Another force behind the project is OSW's objective to encourage the voluntarily implementation of pollution prevention and waste minimization programs in E and P operations. Operators have been practicing waste minimization in E and P operations for several years. Examples include the use of closed loop mud systems in some drilling operations and the recovery of volatile organic compounds (VOC's) and regeneration of glycols and amines at gas plants - all examples of recycling. While the primary benefits to operators are economic, these practices also provide environmental advantages. OSW has been exploring practices and technologies that offer pollution prevention and waste minimization benefits in E and P operations. While some practices have not gained widespread acceptance, they are being used successfully on a daily basis by operators recognizing their advantages, both economic and environmental. Others are innovative technologies that have yet to be proven but offer enough potential to Warrant appropriate field testing. In either case the examples presented illustrate the variety of pollution prevention and waste minimization opportunities available. P. 71
EPA Initiatives for Improving the Management of Crude Oil and Natural Gas Exploration and Production Wastes
Derkics, D.L. (U.S. EPA) | Robinson, B.B. (U.S. EPA) | Souders, S.H. (U.S. EPA)
Abstract Pollution prevention and waste minimization have become essential components of exploration and production (E and P) operations. Environmental accountability necessitates including pollution prevention and waste minimization in well planning and engineering, and waste management programs. Viable approaches should include waste minimization guidelines, employee training, and development of innovative technologies in addition to good housekeeping practices and product substitution. This paper presents several initiatives instituted by the Office of Solid Waste (OSW) of the U.S. Environmental Protection Agency (EPA) for improving the management of E and P wastes. Through these initiatives OSW encourages a cooperative effort among industry, regulatory agencies, and other interested parties to develop creative solutions for improving E and P waste management practices. Introduction In 1980, Congress amended the Resource Conservation and Recovery Act (RCRA) and temporarily exempted from regulation as hazardous wastes those drilling fluids, produced water, and other wastes associated with the exploration, development, and production of crude oil and natural gas. The 1980 Amendments required EPA to study the exempted wastes and submit a Report to Congress detailing the findings of the study and to make recommendations based on the findings. In December 1987, EPA submitted a Report to Congress which concluded that the potential risks to human health and the environment were small and that only a few constituents appeared to be of potentially significant concern. The Report to Congress noted, however, that of the waste management methods in use at the time, some posed the potential for adverse environmental impact if improperly implemented. EPA published a regulatory determination in July 1988 recommending that E and P wastes not be regulated as hazardous wastes under RCRA Subtitle C. EPA further stated that, although existing state and Federal programs were generally adequate, improvements should be made in some programs. The regulatory determination announced EPA's intent to implement a "three-pronged strategy" to address the issues E and P wastes create by:improving federal programs under existing authorities in Subtitle D of RCRA, the Clean Water Act, and Safe Drinking Water Act; working with states to encourage changes in their regulations and enforcement to improve some programs; and, working with Congress to develop any additional statutory authorities that may be required. In the 1980 Amendments, Congress also directed EPA to develop a research, development, and demonstration (RD and D) plan outlining various topics that federal and state governments and/or industry could pursue. In EPA's regulatory determination, the Agency suggested that the RD and D plan should include, among other topics: alternative waste management technologies, waste minimization techniques, materials substitution, and recycling and reuse. OSW is pursuing opportunities to improve state and federal regulatory programs and to enhance E and P waste management practices. Projects underway or proposed include: sponsorship of a second environmental symposium to encourage the exchange of information, review of state regulations to identify possible program gaps, study of selected low volume - high risk waste streams, studies of industry trends in focused areas, and industry outreach. P. 17
- Overview > Innovation (0.69)
- Instructional Material (0.48)
ABSTRACT No preview is available for this paper.
- Energy > Oil & Gas (0.38)
- Transportation (0.31)