Disposal Wells Research Articles

Chemical Fate of Injected Wastes

AbstractThe chemical fate of wastes put into disposal wells can be determined using standard chemical engineering techniques. The concentration of hazardous constituents is typically reduced by reactions within the waste itself or by reactions with the injection zone material, thus reducing any potential impact on the environment. Such reactions include neutralization, hydrolysis, ion exchange, adsorption, precipitation, co‐precipitation and microbial degradation.Extensive research was done to quantify these phenomena, so they could be used in a predictive model.Neutralization, hydrolysis and precipitation were modeled using data from the open literature: reaction rates and equilibrium constants for the dominant reactions were incorporated into a sophisticated computer simulation that calculates solid‐liquid equilibria of aqueous electrolyte solutions.The model predicted the fate of two waste streams: (1) high‐pH, cyanide‐containing waste injected into sandstone is made less hazardous by hydrolysis and sand dissolution, and (2) FeCl3‐FeCl2 HCl‐H2 O waste is made non‐hazardous by reaction with dolomite. Experiments are planned to confirm certain model predictions. Further development and public access of the model are planned.

Study of Current Underground Injection Control Regulations and Practices in Illinois

AbstractIn 1984, the Illinois Department of Energy and Natural Resources was required to assess the regulations and practices of the Illinois Underground Injection Control (UIC) program as it relates to Class I hazardous waste disposal wells. Nine injection wells, including two standbys (one inactive), are currently in operation at seven sites in the state. These wells range in depth from 1540 to 5524 feet (470 to 1683m; most inject wastes into porous carbonate formations (two wells inject into a thick sandstone). In 1984, approximately 300 million gallons (1.1 billion liters) of industrial wastes were disposed of in these wells. Acids were the most common waste disposed of, although water made up 70 to 95 percent of the wastes by volume. Illinois has been granted primacy in operating this program.The geologic environment, consisting of the unit accepting the waste and confining units lying above and below, has the capacity to accept the waste, to retain it, and to protect all underground sources of drinking water (USDW) from contamination by its injection. The geology of Illinois is relatively simple and includes disposal zones and associated confining units suitable for deep‐well injection across the central two‐thirds of the state.The regulatory structure for Class I injection wells is generally adequate in concept and scope to ensure containment of injected wastes and to safeguard underground sources of drinking water in Illinois. There is a need to update and strengthen selected portions of the regulatory practices in the areas of waste sampling protocol, chemical analysis of collected waste samples, and evaluation of injection well testing and monitoring data.A number of technologies exist that can treat and dispose of most hazardous and non‐hazardous waste streams. Each of these technologies has associated with it economic, environmental and societal impacts.

Oil and Gas Developments in Eastern Canada in 1984

Exploration activity continued at a brisk pace in Canadian east coast offshore regions in 1984. Twenty-six wells were spudded, and drilling and/or evaluation continued on another 10 wells. Results were 4 oil wells, 7 gas wells, 1 oil and gas well, 10 dry wells, 1 well under a tight-hole status, 1 relief well, and 12 wells continuing drilling and/or evaluation at year end. Twenty-eight exploration agreements were negotiated, 17 of which were between the Canadian Oil and Gas Lands Administration (COGLA) and various oil and gas exploration companies and cover 9.6 million ha. with a commitment to 17 wells. Eleven exploration agreements were between the Canada-Nova Scotia Offshore Oil and Gas Board and the petroleum industry and cover 2.5 million ha. with a commitment to 14 we ls. In Ontario (including Lake Erie), drilling activity declined slightly from 1983 with 200 wells drilled. Results were 54 gas wells, 26 oil wells, 80 dry holes, 12 suspended wells, and 28 wells classified as other (includes 9 stratigraphic tests, 9 natural-gas storage wells, 4 brine wells, 2 disposal wells, 2 water injection wells, 1 re-entry, and 1 LPG storage well). Oil and gas production in Ontario increased 6.5% and 19.3%, respectively, to 90,376 m3 of oil and 548,166 × 103 m3 of gas. In Quebec, 2 of 12 shallow wells drilled were completed as oil producers. Another well was drilled in Saint Flavien field, but it proved to be dry and was abandoned. Production in Saint Flavien field increased 166% to 11,841 × 103 m3 of gas.

Reclamation On Brine Spills In Upland Boreal-forested Areas

Introduction Large volumes of brine are produced in the oil fields of Alberta each year and disposal lines carrying salt water to the disposal wells occasionally rupture. Much of the oil and gas exploration is centred in the forested portion of the province, yet there is little information on the reclamation of salt spills in the boreal forests. Two spill sites were established in 1977 and four main treatments and three sub-treatments were applied in 1978. Flushing the brine-treated plots with water rapidly lowered the salt content of the soil compared to brine-treated plots. That is, flushing reduced the length of time the soil colloids and flora were exposed to high salt concentrations. The addition of gypsum in combination with flushing lowered the sodium adsorption ratio of soil in the 0 – 30 cm depth and prevented dispersion (liquefaction), thereby substantially reducing the erosion hazard. In contrast, soil/or the 0–30 cm depth in the brine-treated plot that was left to natural forces became a jelly-like mass (liquefaction). Four vascular species were monitored during this study and their response indicated that a combination of flushing, gypsum, fertilizer and a cover crop was superior. The calcium in the gypsum probably had a beneficial physiological effect on the flora. By the fall of 1981, all treatment plots had a complete cover but the brine-treated plots with no flushing had mainly salt-tolerant invader species. Flushing should be undertaken promptly following a spill together with containment plus a follow-up application of gypsum, moderate fertilization and establishment of a cover crop. Introduction Abundant information is available regarding the reclamation of agricultural land affected by waters high in sodium. The Dutch were pioneers in this work because food production in Holland depended on their ability to reclaim land that had been inundated by sea water. Closer to home, White and de Jong(1) conducted a literature review of potential methods for reclamation of salt-damaged soils in Saskatchewan. de Jong(2) then prepared a field manual for the Canadian Petroleum Association outlining actions that should be undertaken to reclaim nonforested lands affected by salt spills in the oil fields of Saskatchewan. However, apart from monitoring studies (Edwards and Blauel(3); Rowell and Crepin(4)), there is little information in the literature regarding the reclamation of forested lands that have been contaminated with brine. The reclamation techniques used for agricultural and nonforested areas may not be applicable to forested areas. In farm lands, amendments normally can be tilled into the soil and there is a good choice of salt-tolerant crops. In forested areas, however, amendments normally should not be tilled into the soil because understory flora (shrubs and mosses) should not be disturbed. To further complicate matters little is known about the effects of concentrated brines on the survival of many of the forest species. Yet, a major portion of oil-related salt spills occur in forested regions of Alberta. Brine production in Alberta over the seven-year period; 1971 to 1978 increase from 16 million m3 to 63 million m3 (100 million to 400 million barrels).

Federal Underground Control Regulations and Their Impact on the Oil Industry (includes associated papers 12562 and 12569 )

Distinguished Author Series articles are general, descriptivere presentations that summarize the state of the art in an area of technology by describing recent developments for readers who are not specialists in the topics discussed. Written by individuals recognized as experts in the area, these articles provide key references to more definitive work and present specific details only to illustrate the technology. Purpose: to inform the general readership of recent advances in various areas of petroleum engineering. Introduction Until the U.S. Congress passed the Safe Drinking Water Act (PL 93–523)in Dec. 1974, regulation of subsurface injection wells was the sole province of the individual states. The Safe Drinking Water Act placed permitting of subsurface injection wells under the control of the Environmental Protection Agency (EPA). However, states were Protection Agency (EPA). However, states were encouraged to adopt or modify their underground injection-control(UIC)regulatory programs to obtain EPA approval, thereby returning authority to the states to administer the UIC program. This return is known as"primacy." During the 1940's and early 1950's, oil-producing states on their own initiative adopted effective regulations for subsurface disposal and injection wells used in oil and gas operations. Among other objectives, state injection-well rules were designed to protect freshwater aquifers. Legislative History History gives convincing evidence that state regulations were effective in protecting underground waters. Documented cases of pollution of fresh water aquifers by oilfield injection and disposal wells are few and limited in area. Congressional recognition of the effectiveness of state control programs wasevident in the original language of the Safe Drinking Water Act. However, Congress expressed its recognition more clearly in the Dec. 1980 amendments to the act (PL 96–502) by instructing the EPA to grant approval to existing state regulatory programs for oil and gas field injection wells programs for oil and gas field injection wells under general-standards rather than the more specific standards imposed on other classes of injection wells. Part C of PL 93–523 setsout the requirements for approvable state programs. Originally, states were required to comply with Sec. 1422 (b)(1)(A). Among other conditions, this section provided that a state program must meet all requirements of EPA regulations in effect under Sec. 1421. The Dec. 1980 amendments to the Safe Drinking Water Act added Sec. 1425, which allowed states greater flexibility in obtaining EPA approval for their existing Class II injection-well program. Sec.1425 gave states the option to demonstrate that their UIC program for Class IIwells generally meets the requirements of Sec. 1421 (b)(1), Subparagraphs (A)through (D), in lieu of the showing required under Sec. 1422 (b)(1)(A). Congress did include the provision in PL 93–523 that regulations and guidelinesadopted by the EPA and the states should not interfere needlessly with oil and gas operations (Sec. 1422[c]). The Senate committee report accompanying the actcomments further on this precaution as follows. …This Amendment prohibits regulations for state underground injection-control programs from prescribing requirements which would interfere with oil or natural gas or disposal of by products associated with such production, except that such requirements are authorized to be prescribed if essential to assure that underground sources of drinking water will not be endangered by such activity. …The Committee'sintent in adopting this amendment was not to require an impossible burden of proof on the states as a condition of promulgation of any such regulations. Rather, the Committee sought to assure that constraints on energy production activities would be kept as limited in scope as possible while still assuring the safety of present and potential sources of drinking water. present and potential sources of drinking water. Similar provisions were adopted with respect to EPA regulations. JPT p. 1409

Protecting water supply aquifers in areas using deep‐well wastewater disposal

The geohydrology of Florida allows deep‐well injection of treated wastewater in some areas if care is taken to assure protection of overlying aquifers used for public water supplies. Precautions are described that must be taken during construction, operation, and ultimate abandonment of the disposal wells to assure containment of injected wastes.

Design of a High-Rate, High-Volume Oil/Water Separator

Summary At ultra-high water cuts (95% or more), the most difficult production problem may not be getting the oil out of the ground, but getting oil out of the water. While it is not uncommon to use large wash tanks to separate the oil from this type of flowstream, few designs can be tailored to a specific application. This paper presents one such design, including the equations used to analyze its performance. This type of analysis can be applied to any separator to predict what its performance should be. Introduction The increasing value of oil is making it economically attractive to install high-volume artificial lift equipment in an oil well, and produce it to a WOR of 125 or more. However, there are few methods for the design of an oil/water separator that will handle effectively liquid inputs of 20,000 B/D or more at these ultra-high water cuts. By developing and presenting the design equations for one such design, this paper describes a foundation for further wok. Large-volume wash tanks often are used as oil/water separators or water polishers in high-rate, high-water-cut applications. Despite widespread use of wash tanks, there are no design equations available to aid in their design1. This paper presents several equations developed while adapting the API separator to oilfield use. It also evaluates design performance with field data. A comparison of actual performance with performance predicted by reaction kinetics equations shows that, for the most part, overall performance approached or exceeded predicted performance. Although some flow characteristics failed to meet the modeled performance, we conclude that the design equations developed are valid for design of a high-water-cut, high-rate oil/water separator. Discussion To take advantage of rising oil prices, many oil companies have increased production from older leases over the past several years. In 1975, Continental Oil Co. (now Conoco Inc.) began a program to maximize production from the Big Lake field, Reagan County, TX. The field was the discovery field of the Permian Basin region and has been on production since 1923. Production has been primarily from the Grayburg limestone, at 3,000 ft (914 m). This reservoir has a strong water drive, and water cuts currently average 90% or more. Liquid productivities are usually more than 3000 B/D (477 m3/d) per well. Most wells on our lease in this field were equipped with high-volume artificial lift in 1975-76 to take advantage of the high productivities of these wells. The lease-wide oil production increase from 290 to 525 B/D (46 to 83 m3/d) was accompanied by an 18,000-B/D (2862-m3/d) increase in water. Total water production, 40,000 B/D (6359 m3/d), exceeded the capacity of the treating facilities on this lease. As a result, oil carryover into the produced-water disposal system increased, going as high as 700 mg/L (0.7 g/dm3) in some tests. This meant losses of about 30 bbl (4.8 m3) oil into the disposal system daily and significant lost revenues. This unseparated oil also caused increased operating costs as water disposal wells began to plug. After reviewing these problems, we decided to buid a satellite battery to handle half the produced liquid on the lease. The central battery was to be modified to increase its treating and disposal capacity to 32,000 B/D (5088 m3/d) by installing some type of water-polishing device between the existing free-water knockouts and the produced-water disposal system. Although the capacity of this water-polishing device at ultra-high water cuts was the primary design criterion, several other factors had to be considered.

Deep-well waste disposal in the Federal Republic of Germany — A state-of-the-art report

Deep-well disposal of liquid waste is practised in the Federal Republic of Germany at 31 sites. There are • - 17 disposal wells in Lower Saxony, injecting brines with polysulfide compounds from natural gas extraction; • - 1 disposal well in North Rhine-Westphalia. Injection of brine from salt solution mining has been postponed as the brine is now being chemically processed; • - 10 injection wells in the “Werra Potash District” (Hesse) for the disposal of process brine; • - 1 disposal well in the “Fulda Potash District” (Hesse), operating for the injection of surface runoff from a salt mine waste dump; • - 2 injection wells at Moosburg/Isar (Bavaria) disposing of spent hydrochloric acid.

Performance Simulation of the Snipe Lake Beaverhill Lake A Pool A Geologically Complex Reservoir

Abstract This paper illustrates the inter-relationship of geology and reservoir engineering in reservoir simulation. A three-phase, three-dimensional, unsteady-state model study was U1ldertaken to resolve the complex pressure and p1'oduction characteristics of the Snipe Lake Beaverhill Lake A Pool and allow 'meaningful predictions of future performance. The study began with a detailed investigation of the geology of the pool to allow the definition and generation of the basic 'model data input. Additional studies of the production, perforation and pressure histories of the wells, taking into account the layering concepts developed in the geological study, helped to indicate broad performance concepts. The history 'matching of the performance, however, proved to be very complex and involved altering the original geological picture of the pool. Introduction THE SNIPE LAKE Beaverhill Lake A Pool, located 160 miles northwest of Edmonton, Alberta (Fig. 1). was discovered in December, 1962 by the drilling of SOBC Snipe 10-21-70-18W5. Development was rapid, with 95 wells completed in the first two years. There are now 108 wells completed within the current pool boundaries, 106 of which are in the Snipe Lake Beaverhill Lake Unit No.1. The pool is approximately 28 miles long (orientated to the northwest) and was less than 5 miles wide in the oil zone at original conditions. There is aquifer downdip to the southwest, although its full extent has not been determined by drilling. The pool is an undersaturated oil accumulation located approximately 8700 feet below surface. The reservoir pressure declined rapidly under primary depletion from the initial pressure of 3815 psig toward the saturation pressure of 1300 psig. The aquifer did not contribute significantly to the reservoir energy. A pilot waterflood was initiated in October, 1964, with fresh-water injection at 4-17-71-18W5, and this was expanded to a full-scale flank waterflood in 1965 with four injectors. Additional injectors have been added since then, until now there are eight fresh water injectors and two produced-water disposal wells. As the waterflood matured, it was apparent that less-sophisticated reservoir evaluation methods were inadequate in resolving the complex pressure and production characteristics of the pool. Fortunately, improved solution routines were making the use of three-dimensional, three-phase, unsteady-state simulators practical for fairly large reservoirs such as Snipe Lake. A comprehensive reservoir model study was thus undertaken to establish revisions in previous theories regarding the waterflood displacement in the pool in order to explain current performance, to predict the results of possible changes in the waterflood scheme and to determine ultimate recovery. The study began with a detailed geological review, which confirmed the complex nature of the pool. A review of the production, perforation and pressure histories of the wells, taking into account the layering concepts developed in the geological study, helped to indicate some broad performance concepts. However, history matching the pool performance revealed that there were significant restrictions in lateral communication between wells which were not apparent from 160-acre well control. Pool Geology The Snipe Lake reservoir is an atoll-like reef in the Swan Hills Formation.

Subsurface Brine Disposal – Be Reasonablea

ABSTRACTA classical battle between landowners desiring to protect their fresh ground water from pollution and oil companies needing a disposal zone for injection of oil‐field brines developed in Texas County, Oklahoma.Initial studies showed that the disposal zone (Glorieta Formation) was in places only 500 feet below the bottom of the fresh‐water aquifer (Ogallala Formation). Furthermore, solution/collapse features in the intervening formations plus numerous poorly plugged wells and exploration holes provided potential avenues of brine migration. The potential for pollution appeared very real. The landowners not only wanted to halt construction of new brine disposal wells, but also wanted all 33 existing disposal wells abandoned and plugged. Tempers flared and intermittent litigation continued for over two years.A more complete hydrogeologic analysis led to the following observations: (a) the potentiometric surface in the Glorieta is 100 to 400 feet below the water table in the Ogallala in areas where brine disposal is taking place; and (b) the transmissivities of the Glorieta and disposal rates are such that even pressure gradients around disposal wells are below the water level in the Ogallala. These hydrologic facts led to the conclusion that, even with a perfectly open conduit connecting the two formations, migration of disposal brine from the Glorieta into the fresh‐water Ogallala would be impossible in the critical area because of pressure relationships.Techniques using “pressure bombs” and test injection data are presented by which transmissivity values in the Glorieta were estimated. Disposal well design and completion methods used by the oil companies were found to be inefficient and contributed to operational problems. Specific regulations were adopted regarding disposal wells to further assure that pollution of the Ogallala would not occur.As a result of all parties understanding the hydro‐geologic factors, the oil companies are continuing to use the Glorieta as a disposal zone and the fearful landowners are assured that no real pollution hazard exists. This outcome assures full use of all natural resources–which is true conservationism. Ground‐water technicians not only have a responsibility to use and protect ground‐water resources, but also to assure that unnecessary cost burdens are not placed on other industries in the name of pollution prevention.

Subsurface Disposal of Fluid Wastes in Saskatchewan: ABSTRACT

In the Williston basin region, deep-well disposal of industrial fluid wastes is confined largely to the Saskatchewan part of the stable, relatively shallow, tectonic shelf, which is flanked on the south by the deeper basin proper, and is delimited in the north by the Canadian shield. As of mid-1973, 30 industrial disposal wells had been drilled in Saskatchewan: 20 were in operation, 5 suspended, and 5 abandoned. To year-end 1972, more than 118.995 million bbl of fluid wastes, exclusive of oilfield brines, had been injected into subsurface aquifers in Saskatchewan: (1) waste brines (63,440,000 bbl), resulting from shaft and solution mining, as well as experimental solution of Devonian potash deposits; (2) waste brines (50,930,000 bbl), produced during solution mining of caverns in Devonian halite for subsequent storage of liquefied petroleum gases and dry natural gas; (3) refinery effluent (3,530,000 bbl), comprising sour water and spent caustic from 2 plants; and (4) brines containing small amounts of mercury compounds End_Page 910------------------------------ (221,000 bbl) from a chlor-alkali plant, associated with previously injected wastes (874,000 bbl) from production of the herbidices 2, 4-D, and MCPA. The depths of injection intervals range from 1,448 to 4,692 ft. The maximum total depth of a disposal well in Saskatchewan is 5,536 ft. Average injection rates are from 3 to 1,100 US gpm and average well-head pressures vary from the sole influence of gravity to 1,750 psig. More than 44.13% of all industrial wastes injected into the Saskatchewan subsurface are received by clastic aquifers. In 18 injection systems, clastic units (Cambrian and Ordovician; Lower Cretaceous) are the disposal intervals, whereas 13 wells have been completed for disposal into carbonate units (Silurian to Mississippian). There are four multizone completions, each involving disposal of potash brines into a Silurian carbonate aquifer and an Ordovician clastic aquifer. In three disposal systems, mercury compounds are permitted to accumulate in caverns in Devonian evaporite strata. End_of_Article - Last_Page 911------------

Effect of Subsurface Waste-Disposal Practice on Groundwater Resources in Hawaiian Islands: ABSTRACT

Geologic and hydrologic framework (K. J. Takasaki): Groundwater in Hawaii is present as basal water, as dike-impounded water, and as perched water. Basal water, the fresher part of it forming a lens-shaped body floating on saline groundwater, is in dike-free volcanic rocks and in sedimentary rocks. Dike-impounded water is confined to volcanic rocks in eruptive zones. Perched water is present in all rocks and at all altitudes. Most recharge to groundwater is in the wet interior mountains. Therefore, the main areas of recharge are upgradient from developed areas where most wastes are disposed of in the subsurface. This natural deterrent, by position of the recharge area, so far has kept much of the groundwater in its pristine quality state. Deterioration of the groundwater will increase as land developments encroach toward the recharge areas-the degree will depend greatly on the waste-disposal practices. Most natural discharge of groundwater is along the shore, downgradient from disposal wells. The contamination of the beaches rather than of the water supply is the main concern regarding subsurface disposal of wastes in the low areas under present conditions. Hydraulic, geochemical, and monitoring aspects of liquid-waste injection under Ghyben-Herzberg equilibrium End_Page 1453------------------------------ conditions (F. L. Peterson).-The success of injection operations depends primarily on injection capacity and fate of the injected waste. To evaluate these factors properly an understanding must be obtained of local hydrogeologic conditions, hydrodynamics of injection under Ghyben-Herzberg lens conditions, and possible chemical and biologic effects. Hawaiian hydrogeology is understood fairly well, and where adequate information is not available, it usually is possible to collect these data by careful field investigation. Considerable information is available from other parts of the world on the hydrodynamics of waste-water injection. However, much of this information is not directly applicable to injection in the Hawaiian environment. Particularly troublesome are the complications caus d by the extreme heterogeneity of Hawaiian receiving formations and Ghyben-Herzberg lens effects. Likewise, because chemical and biologic reactions depend on the nature of the injected waste, the receiving waters, and the receiving formations, many of the data collected elsewhere are not applicable in Hawaii. End_of_Article - Last_Page 1454------------

Where Have All the Toxic Chemicals Gone?a

ABSTRACTMany municipal, industrial, domestic and farm water supplies throughout the country are derived from wells tapping shallow aquifers that have a high contamination potential from surface derived sources. Unfortunately, water samples from most of these wells are not analyzed on a regular basis even for bacteria or simple chemical pollutants such as nitrate. Practically none of them are routinely checked for more serious contaminants such as viruses, weed killers, pesticides, trace metals, and an almost countless number of toxic chemical compounds commonly used in our environment and eventually discarded in garbage dumps, waste‐burial grounds, or disposal wells. Because of this, the possibility of serious ground‐water contamination often is not discovered until a high degree of contamination is present.Microorganisms contained in water may be effectively removed by filtration in a short distance of travel through fine‐grained earth materials. However, most toxic chemical compounds are not. Instead, these are carried by precipitation recharge to surficial ground‐water reservoirs. After entry such contaminants move downgradient through the aquifer materials, usually at rates of only a few feet per year with little if any dilution, to natural discharge points such as streams, lakes and swamps, or to pumping wells.Ground‐water contamination occurrences from nitrate, arsenic, chromate, cadmium, chlorinated hydrocarbons, and a large number of other toxic chemicals are increasing. These show that a serious threat to public health may be imminent unless all surficial and underground disposal sites of toxic chemicals are located, the extent and magnitude of ground‐water contamination from each site evaluated, and corrective measures applied where necessary.

Subsurface Disposal of Waste in Kansas: ABSTRACT

The use of wells for the subsurface disposal of wastes has been practiced in Kansas since 1935. All the early waste-disposal wells were used to dispose of oil-field brine. Permits for the first industrial waste-disposal wells other than oil-field wells were issued in 1952. Two state agencies have jurisdiction over the subsurface disposal of oil-field wastes in Kansas. Before using a well for the subsurface disposal of oil-field or gas-field brines, the operator must submit plans and specifications for each disposal well to the Kansas State Corporation Commission. These must be approved by both the State Corporation Commission and the Kansas State Department of Health. The Corporation Commission, through its Oil and Gas Conservation Division, determines that the use of the proposed well will not result in loss or waste of gas or petroleum resources. The Department of Health, through its Oil Field and Subsurface Disposal unit, Division of Environmental Health, determines that use of the proposed well will not result in pollution to the water resources of he state. Before using a well for the subsurface disposal of industrial wastes other than oil-field or gas-field wastes, an application must be filed with, and a permit issued by, the Kansas State Department of Health. The maximum wellhead pressure that may be used to inject wastes into both classes of wells must be approved by the Department of Health. Periodic field checks of the amount of pressure used are made by field personnel of the Department of Health. The Oil Field and Subsurface Disposal unit is staffed by a supervisory geologist in Topeka and by 8 area geologists, each of whom is responsible for a specific section of the state. At present, there are 3,200 approved oil-field and gas-field saltwater disposal wells in use receiving a total of about 4,000,000 bbl of salt water per day. Not included are 2,600 saltwater repressuring systems in the state, which are made up of from one to several hundred injection wells. The depths of the oil- and gas-field disposal wells range from less than 500 to about 6,000 ft. Thirty-eight zones ranging from Upper Permian to Precambrian are being used. About 60% of the wells inject wastes into limestones or dolomitic rocks, 25% into sandstone, 5% into sandy or gypsiferous shale, 5% into salt or anhydrite zones, and 5% into conglomerate or granite wash. Injection pressures being used range from gravity at the wellhead to 0.5 psi/ft of depth to the injection zone. There are 31 industrial waste-disposal wells (other than oil- or gas-field wells) at 21 plants in the state including 10 LPG underground storage projects, 2 salt companies, 3 petroleum refineries, 4 natural gas compressor stations, 2 chemical manufacturing plants, and 2 fertilizer plants. Most industrial waste being disposed of in the subsurface consists of salt brine and is disposed of in Arbuckle rocks at depths ranging from about 3,000 to 6,000 ft. All wells are constructed to preclude any hazard to fresh water. The Department of Health's present policy concerning industrial wastes is that only those wastes that cannot be treated and disposed of by other practical methods will be considered for disposal in the subsurface. Use of the most permeable injection zone available at each s te is required regardless of depth in order to eliminate the need for wellhead injection pressure. Experience with both industrial and oil-field disposal wells shows that most operational problems are caused by (1) selecting an injection zone with inadequate permeability, (2) no preliminary waste treatment or inadequate waste treatment, or (3) failure to provide an effective maintenance program. End_of_Article - Last_Page 1599------------

Hydrogeologic and Economic Factors in Decision Making Under Uncertainty for Normative Subsurface Disposal of Fluid Wastes, Northern Williston Basin, Saskatchewan, Canada: ABSTRACT

The normative subsurface waste-disposal condition of no hazard to population, coupled with optimum allocation of drilling funds, can be achieved best through search for primary and alternative disposal formations by evaluation of hydrogeologic data on a basinwide scale. Any decision to drill a disposal well in Saskatchewan is made under considerable uncertainty, which is a reflection of the present reconnaissance level of subsurface information. Subsurface disposal of fluid wastes in the Williston basin region is largely restricted to sandstone and carbonate aquifers (Cambrian through Lower Cretaceous) of the Saskatchewan-Manitoba tectonic shelf: (1) oil-field brines (at rates of the order of 15 gpm); (2) waste brines from exploitation of Devonian potash deposits (up to 750 gpm); (3) waste brines from solution mining of LPG-storage caverns in Devonian halite (up to 300 gpm); (4) refinery sour water and spent caustic (up to 20 gpm); and (5) chlor-alkali-plant wastes (up to 15 gpm), partly associated with previously injected herbicide wastes. Hydrogeologic constraints on development of subsurface waste-disposal systems, not related to reservoir quality of disposal formations but likely to influence waste migration, are (1) proximity of the outcrop belt on the north and east, (2) pre-Cretaceous valley systems controlling development of fluvial channels up to the present, (3) sinks formed through localized solution of Paleozoic halite, and (4) positive basement features and related overlying structures. Estimated ultimate capital investments for existing Saskatchewan injection systems range from $20,000 to $100,000 in the oil fields, to more than $300,000 for some potash-brine disposal wells, and are determined largely by depth of disposal formation, drilling technique, and well design. Potash-brine disposal wells in the vicinity of shaft mines include the most costly and refined systems, and involve directional drilling to formations below the potash unit and mud programs employing fluids compatible with evaporite minerals. End_of_Article - Last_Page 1594------------

Subsurface Disposal of Liquid Industrial Wastes in Alabama: ABSTRACT

Five subsurface disposal wells have been drilled and completed in Alabama. These are: Stauffer Chemical Co., Mobile County; Ciba-Geigy, Inc. (2), Washington County; U.S. Steel Corp., Jefferson County; and Reichhold Chevmicals, Inc., Tuscaloosa County. The Geological Survey of Alabama has been involved directly in all 4 projects. The Survey served as a consultant to the Alabama Water Improvement Commission (the state agency responsible for protection of surface and groundwater in Alabama) on the Stauffer and Ciba-Geigy projects, and as consultant and supervisor on the U.S. Steel Corp. and Reichhold Chemicals, Inc., projects. The Environmental Protection Agency provided some funding on the research aspects of the Reichhold Chemicals, Inc., disposal well. These projects were undertaken as a research effort to insure that the responsible state agencies are fully cognizant of all aspects of this method of waste disposal. At present, in Alabama, subsurface disposal is permissible for some types of wastes, if the well is properly designed and completed in an appropriate geologic environment, if conventional methods of waste treatment have been evaluated and proved to be inadequate, and provided an adequate monitoring system has been installed. The Stauffer and Ciba-Geigy wells are in the Coastal Plain geologic province and the U.S. Steel and Reichhold Chemicals, Inc., wells are in Paleozoic sediments of the Warrior basin, The geology, drilling, completion, and testing techniques are presented as a basis for decision making for approval or rejection of the proposed deep-well disposal projects by a regulatory agency. End_of_Article - Last_Page 1596------------

Artificial Recharge of Treated Waste Waters and Rainfall Runoff into Deep Saline Aquifers of Peninsula of Florida: ABSTRACT

Fast-growing population centers of the state of Florida, mainly in coastal beaches, have imposed large demands on the sources of fresh water. They also threaten to deteriorate the esthetic and recreational value of the area with their waste waters. The largest of these population centers is on the southeastern end of the peninsula of Florida, commonly referred to as the Miami area. The second largest is on the central west coast of the peninsula in the Tampa-St. Petersburg area. The Florida peninsula is underlain by several thousand feet of carbonate rock, with only minor amounts of clastic sediments. Cavernous limestone and dolomite aquifers at relatively shallow depths constitute the principal source of fresh water in the area. Deeper cavernous zones, separated from the freshwater zones by practically impermeable limestone and dolomite, are uniquely suited to receiving injected fluids. Deep-well disposal of waste waters into deep saline aquifers, after secondary biologic treatment and disinfection, is feasible if (1) an aquifer exists that can accept treated waste waters without significant changes in its hydraulic and structural characteristics, and (2) if use of the water in that aquifer, adjacent ones, or from surficial sources is not impaired. Two large disposal wells have been constructed for a private utility in the Miami area of southeast Florida. They are approximately 3,000 ft in depth and recharge an artesian aquifer having chloride concentrations near that of seawater (19,000 mg/l). The receiving aquifer is overlain by a thick aquiclude, by another aquifer (saline but of lower chloride concentration), and then by a thick, impervious section separating the highly mineralized waters from the shallow and fresh groundwater. Three concentric steel casings, cemented at the proper depths, permit injection into the deeper aquifer with protection of the upper strata. Monitoring of the upper saline water-bearing stratum, where any possible leak from the deeper aquifer would normally be first detected, is performed through the annulus between the 2 inner well casings. An integrated water-quality aquisition system continuously monitors the injected waste and provides an alarm and pump shut down if established limitations are exceeded. Operation of the first well for over a year has proved fully reliable, and economically advantageous. Eight similar disposal wells are being considered in the area. On the basis of this experience, a new research program is being implemented to inject, store, and recover when needed, rainfall runoff into the deep saline aquifers of southern Florida. A test-prototype well is presently being constructed within the city of St. Petersburg to determine (1) the characteristics of the deep underground formations; (2) the quality of the deep groundwaters; (3) the injection rate capacity and associated increase in pressure; (4) the ratio of the amount of fresh water that could be subsequently recovered to that injected; and (5) the quality of the recovered water. End_of_Article - Last_Page 1595------------

Subsurface Disposal of Liquid Industrial Wastes in Alabama—A Current Status Reporta

ABSTRACTFour subsurface disposal wells have been drilled and completed in Alabama. These are: Stauffer Chemical Company, Mobile County; Ciba‐Geigy, Inc., Washington County; U. S. Steel Corp., Jefferson County; and Reichhold Chemicals, Inc., Tuscaloosa County. The Geological Survey of Alabama has been directly involved in all four projects. The Survey served as a consultant to the Alabama Water Improvement Commission, the State agency responsible for protection of surface and ground water in Alabama, on the Stauffer and Ciba‐Geigy projects, and as consultant and supervisor on the U. S. Steel Corporation and Reichhold Chemicals, Inc., projects. These projects were undertaken as a research effort to insure that the responsible State agencies are fully cognizant of all aspects of this method of waste disposal. It is a policy in Alabama that subsurface disposal is permissible for some wastes if the well is properly designed and completed in an appropriate geologic environment and if conventional methods of waste treatment have been evaluated and proved to be inadequate.The Stauffer well, operating at 75 gallons per minute and 500 psi, is the only subsurface disposal system, other than oilfield brine disposal wells, that is currently in operation. The Stauffer and Ciba‐Geigy wells are in the Coastal Plains geological province and the U. S. Steel and Reichhold Chemicals, Inc., wells are in Paleozoic sediments of the Warrior Basin. A general discussion of the geology, drilling, completion, and testing techniques is presented for the two geologic provinces involved.

Subsurface Storage and Disposal in Illinoisa

ABSTRACTThe storage of both liquids and gases in underground strata has become rather common in Illinois.The problem of disposal of fluid industrial wastes has caused greatest concern, especially for the possible effects on ground‐water quality. Necessary precautions have been established in the requirements of the Illinois Environmental Protection Agency (IEPA) which has authority to control, prevent, and abate pollution of streams, lakes, ponds, and other surface and underground waters in the State. Before any construction can begin on storage in subsurface strata, a permit must be secured from the IEPA. Eight basic design policies have been adopted that have to be met before a construction permit will be issued.Sandstone, limestone, and dolomite are the basic lithologies most commonly considered as potential disposal reservoirs in Illinois. From well cores of such formations, essential laboratory studies are conducted defining the rate of fluid movement, porosity, and permeability of the rock and the pressure distribution within the aquifer.Plugging of the injection horizon is the most serious cause of damage to a fluid injection system and results from the forming of an impermeable deposit on the well bore or plugging in the formation itself. In either case the plugging may result from a number of listed causes.To date there have been four industrial waste disposal wells in Illinois. Variation in conditions is illustrated by these cases of disposal wells that have been authorized by the State.The first practical use of underground gas storage in Illinois was at Waterloo in 1950. Since then, the number of projects and their capacities have grown continuously. At the present time there are 24 underground gas storage projects. Gas injection pressures must be kept below the fracturing pressure of the caprock. In underground gas storage reservoirs in Illinois, injection pressures of approximately 0.55 psi per foot are often used.Secondary recovery by water flooding accounted for 73.4 percent of the total oil production in Illinois during 1968. In that year there were 880 active projects in Illinois with 13,107 water injection wells that injected 2581 million gallons of water.

Control of Unconsolidated Sands in Waste-Disposal Wells: ABSTRACT

Sand control methods were first used in water wells, and later, modified methods were applied to oil and gas wells. The most recent application for sand control is in waste-disposal wells. The increasing use of unconsolidated sands as disposal zones has created a need for better sand-control systems. We suggest that the primary causes of sand control problems in disposal wells are: (1) greater completion intervals, (2) intermittent operation of the well, and (3) chemical characteristics of the injected effluent. Therefore, successfully to prevent sand production in disposal wells, consideration must be given to: (1) formation characteristics, (2) completion fluid, (3) type of completion, and (4) completion method. Two universally used methods of sand exclusion, with suggested modifications when applied to disposal wells, are the method of in-place sand consolidation with plastics, and the use of gravel packs in conjunction with sand screens. Sand consolidation has limited application owing to the large completion intervals normally used in disposal wells, and to possible chemical reactions with injected effluent. However, a gravel-packed-sand-screen completion generally eliminates the three primary causes of sand production in disposal wells. Factors of prime importance are (1) the drilling and completion fluids, (2) formation grain size and composition, (3) size and amount of gravel, (4) pumping rate, (5) pressure, and (6) gravel concentration. Field and laboratory data show that the method of gravel-packed-sand-screen completions can be used successfully over intervals as large as 500 ft in unconsolidated Frio sands. End_of_Article - Last_Page 2084------------