The Experts below are selected from a list of 87 Experts worldwide ranked by ideXlab platform
George H. Holliday - One of the best experts on this subject based on the ideXlab platform.
-
Lime Treatment of Oily Saline Drilling Wastes
SPE Production & Facilities, 2001Co-Authors: Lloyd E. Deuel, George H. HollidayAbstract:Summary Land treatment of oily saline drilling wastes is problematic in low-pH, high-iron, and aluminum-activity soils commonly found in China, Southeast Asia, and the Americas. Problems stem from the addition of salts promoting hydrolysis of iron and aluminum acidity, exacerbating an often extreme (pH < 4.0) acid reaction. Most drilling wastes are strongly alkaline and offer a beneficial neutralization reaction when mixed with native acid soils. However, land treating of oily saline drilling wastes generally is limited by either the petroleum hydrocarbon content or salinity before sufficient base is added to neutralize excess acid in the receiving native soil. This paper offers a practical and economical means of managing potentially problematic reactions by the prophylactic treatment of oily saline drilling wastes with agricultural-grade hydrated lime (calcium hydroxide) prior to land application. The results presented show that hydrated lime reacts with the oil-base drill cuttings/acid-soil mixture in a manner promoting the biological degradation of the oil. Lime also functions to sequester free-oil fractions, making it easier to land-apply oily wastes and to control application rates. Free lime neutralizes excess soil acidity. The high pH associated with hydrated lime is ameliorated in the lime/drilling waste/receiving soil blend by fixation of atmospheric carbon dioxide to a pH < 8.3 (carbon dioxide and water naturally attain a pH of about 8.3, as shown by the decrease of Reserve Pit fluid pH with time). The data suggest that the optimum lime application is equivalent to the total petroleum hydrocarbon (TPH) content as measured on a dry-weight basis. Introduction Excessive acid soil reactions make some cations unavailable to plants and release other cations in toxic concentrations.1–6 Optimum pH for plant growth is 6.5 to 6.8; however, most plants tolerate a pH range of 5.5 to 7.5.7 Low soil pH reduces nutrients available in soil. Rorison and Clarkson report that the reduced nutrients result from preciPitation of phosphorus by aluminum in the soil.4,5 Indirect impacts of low soil pH include impaired nitrification (microbiological conversion of ammonia to nitrate) and attack of soil-borne pathogens on plants.6 Extremely acid reactions (pH < 4.0) render land treatment of oily saline wastes difficult, because the addition of salt promotes hydrolysis of iron and aluminum acidity, which increases the activity of hydrogen ions and further lowers the soil pH. Disruption of the carbon and nitrogen cycle reduces or extinguishes the biological action necessary for land treatment of TPH's. Low-pH soils exist in oil provinces of China, North America, and South America. Observations by the authors reveal dark red (iron) fluid seeps on slopes adjacent to closed drilling Pits in South America. This indicates soil pH < 3.5. Sparling developed solubility curves showing that ferric iron causes no toxicity problem at pH > 3.5. Aluminum and manganese are generally not a factor above pH 5.0.8 Most drilling wastes are strongly alkaline (pH > 10) and provide a beneficial neutralizing reaction when mixed with acid soils. However, most drilling Pits are closed by dewatering and burial.9 Thus, the wastes are not mixed with the acid background soil to effectuate an increased pH admixed soil. The concept of the treatment discussed in this paper is based on adding lime reagent to oily drilling waste before combining the waste with the acid soil. Typically, agricultural lime is added to soils in the form of finely ground calcite, CaCO3, or hydrated lime, Ca(OH)2. We selected hydrated lime for the present study because it yields an initially higher pH on reaction with water and a more rapid rate of reaction. Materials and Methods Drill Cuttings. Study materials, consisting of a mixture of drilling mud and cuttings, were collected in eastern Oklahoma during drilling operations conducted in November 1999. The drilling waste mixture used in the study was composed of 12.6% fuel oil, 11.2% water and 76.2% solids. Fuel oil was measured as, first, TPH by infrared spectroscopy (TPH-IR) using EPA Method 418.1, second, oil and grease using EPA Method 9071B; and third, diesel-range organics (DRO) using EPA Method 8015B. The unweathered values for TPH-IR, oil and gas and DRO were 12.6%, 12.0%, and 11.6%, respectively. The pH and salinity of the drilling waste were determined for a 1:1 solid/water extract prepared from waste solids dried at 350°C and ground to pass a 2-mm mesh sieve. The pH of the drilling waste measured 7.78. Salinity was measured as specific electrical conductance (EC), yielding a value of 21.9 mS/cm. Treatment Soil. The soil used in the lime treatment study was a Lufkin fine sandy loam (Vertic Albaqualfs). This soil was from an unimproved pasture located in Brazos County, Texas, and representative of the Ap horizon (0 to 18 cm). Select physical and chemical properties of the treatment soil are listed in Table 1. Experimental Design. Treatments consisted of four lime application levels (0, 10, 20, and 50% by total weight) and three waste-solids-to-soil application ratios (1:1, 1:2, and 1:4) superimposed on sterilized and unsterilized soil. Sterilization consisted of oven drying at 105°C for 48 hours. The intent of sterilization was to substantially reduce microbial populations of the soil without altering the organic matter content of the receiving soil. The drilling wastes were treated with lime by adding 30 g lime to 270 g waste solids (10%), 60 g lime to 240 g waste solids (20%), and 150 g lime to 150 g waste solids (50%). Neat (0% lime) and lime-treated drilling-waste solids were then added to sterilized and unsterilized Lufkin soil at a mix ratio of 1:1 (50 g waste solids:50 g soil), 1:2 (33.3 g waste solids:66.6 g soil), and 1:4 (20 g waste solids:80 g soil). Soil moisture at 22.7% was taken into consideration when adding unsterilized soil to keep the dry-weight equivalency the same as the sterilized soil. The waste/soil mixture was placed in a shallow dish microcosm and water added to yield one treatment moisture level of 35% to initiate the experiment. The mixtures reacted under laboratory conditions for 120 days, the time allotted for the experiment. Water was added daily to maintain the 35% moisture equivalent. Chemical Analyses. Soil samples were collected from each microcosm at the conclusion of the experiment and analyzed for moisture, pH, EC, and TPH. The pH and EC were measured on a 1:1 treated soil/water extract using EPA Methods 9045 C and 9050 A, respectively. Test parameters were subjected to an analysis of variance (ANOVA) to evaluate treatment effects as sources of variation.
-
Observed Contaminant Migration from an Instrumented Reserve Pit
All Days, 2000Co-Authors: Lloyd E. Deuel, George H. HollidayAbstract:Abstract A 3.3-meter deep fresh water drilling fluid Reserve Pit was instrumented to determine migration of contaminates from the Pit during drilling and after Pit closure. The ability to predict impacts from earthen drilling Pits has become important, due to the recognized potential for an adverse impact on soil and water resources. The results of the field study allow operators to control chemical composition of Pit wastes to prevent contaminants from migrating from an active or closed Pit. To the best of our knowledge, no other Reserve Pit has been evaluated by instrumentation installed a priori to evaluate the environmental impact of Reserve Pits. The Pit was equipped with neutron probe access tubes, barrel size lysimeters, vacuum extraction moisture cups and gypsum resistively blocks at 4 stations within the Pit perimeter. Ground water monitoring wells, and post closure soil borings were used to assess the long-term affects of the earthen Pit use and onsite disposal of the Pit waste solids on soil and ground water resources. The soil moisture and chemical data generated during the 2-year field study was evaluated statistically utilizing analyses of variance (ANOVA). Soil water monitoring during Pit use showed the soil profile below the Pit remained unsaturated under the influence of a 3.3-m head of Pit fluid. This demonstrated the clay gels [spud mud] serve as a Pit surface sealant and retards percolation of fluids from the Pit. Chlorides were retained in the Pit by an anion exclusion mechanism. This mechanism remained stable and the exclusion volume functional in Pit solids having Saturated Paste Electrical Conductivity [SPEC] of = 24 mmhos/cm. Post closure data show clean closure of the study Pit and no alteration of intended land use (improved pasture) or adverse impact to the natural environment. Introduction This field study, sponsored by the Petroleum Environmental Research Forum [PERF], assess the impact to ground water and soil of fresh water drilling fluids contained in an earthen Reserve Pit. Nearly all Reserve Pit studies reported in the literature concentrate on after-closure affects (Murphy and Kahew, 1984). Accordingly, environmental effects caused by the Pit contents must be inferred by extrapolating post-closure information. The instant study measures the real-time environmental effects of a Reserve Pit from construction, use and through 2-years of post-closure monitoring. Reserve Pits are a practical method of storing spent drilling fluids, and drill cuttings. Drilling fluids serve a variety of purposes, the most important being, controlling formation pressures. Typically, drilling fluids fall into four categories:Fresh water base - where the continuous phase is fresh waterSalt water base - where the continuous phase is salt waterOil base - where the continuous phase is hydrocarbon or mineral oilEmulsion base - where an oil-in-water or water-in-oil emulsion is the continuous phase Fresh water base drilling fluids represent 85 to 90 percent of the total drilling fluids in use, because of low toxicity, ease of treatment, low temperature stability and low cost. Except for areas where massive salt deposits exist, fresh water is the drilling fluid of choice for shallow drilling.
-
Measurement of Solute Transport from an Earthen Reserve Pit During Drilling and Post Closure Operational Phases: Part I. Site Characteristics and Experimental Design
All Days, 1999Co-Authors: Lloyd E. Deuel, Shawn Hokanson, George H. HollidayAbstract:This paper was prepared for presentation at the 1999 SPE/EPA Exploration and Production Environmental Conference held in Austin, Texas, 28 February-3 March 1999.
Edward C. Murphy - One of the best experts on this subject based on the ideXlab platform.
-
Groundwater Quality Beneath a Buried Oil and Gas Reserve Pit in Western North Dakota
Journal of Environmental Solutions for Oil Gas and Mining, 2015Co-Authors: Edward C. MurphyAbstract:INTRODUCTION In the 1980s, the North Dakota Geological Survey led the Rocky Mountain Region and the Northern Plains in the study of the impacts of buried drilling fluid on shallow groundwater (Murphy and Kehew, 1984; Beal et al., 1987, Murphy, 1988). As a result of this work, it was recognized that buried drilling mud could adversely impact the environment even when buried above the water table in a semi-arid environment. The 1984 report proved that drilling mud leachate was being generated at these sites and this leachate had the potential to negatively impact shallow groundwater in vulnerable settings. All three reports recommended drilling mud not be disposed of in floodplains and other areas with high water tables and permeable sediments. That recommendation was repeated at a number of presentations throughout western North Dakota as well as nationally regarding the safe disposal of drilling mud. It was pointed out that it did not make sense to place a synthetic liner in a Reserve Pit only to rip out ...
Lloyd E. Deuel - One of the best experts on this subject based on the ideXlab platform.
-
Lime Treatment of Oily Saline Drilling Wastes
SPE Production & Facilities, 2001Co-Authors: Lloyd E. Deuel, George H. HollidayAbstract:Summary Land treatment of oily saline drilling wastes is problematic in low-pH, high-iron, and aluminum-activity soils commonly found in China, Southeast Asia, and the Americas. Problems stem from the addition of salts promoting hydrolysis of iron and aluminum acidity, exacerbating an often extreme (pH < 4.0) acid reaction. Most drilling wastes are strongly alkaline and offer a beneficial neutralization reaction when mixed with native acid soils. However, land treating of oily saline drilling wastes generally is limited by either the petroleum hydrocarbon content or salinity before sufficient base is added to neutralize excess acid in the receiving native soil. This paper offers a practical and economical means of managing potentially problematic reactions by the prophylactic treatment of oily saline drilling wastes with agricultural-grade hydrated lime (calcium hydroxide) prior to land application. The results presented show that hydrated lime reacts with the oil-base drill cuttings/acid-soil mixture in a manner promoting the biological degradation of the oil. Lime also functions to sequester free-oil fractions, making it easier to land-apply oily wastes and to control application rates. Free lime neutralizes excess soil acidity. The high pH associated with hydrated lime is ameliorated in the lime/drilling waste/receiving soil blend by fixation of atmospheric carbon dioxide to a pH < 8.3 (carbon dioxide and water naturally attain a pH of about 8.3, as shown by the decrease of Reserve Pit fluid pH with time). The data suggest that the optimum lime application is equivalent to the total petroleum hydrocarbon (TPH) content as measured on a dry-weight basis. Introduction Excessive acid soil reactions make some cations unavailable to plants and release other cations in toxic concentrations.1–6 Optimum pH for plant growth is 6.5 to 6.8; however, most plants tolerate a pH range of 5.5 to 7.5.7 Low soil pH reduces nutrients available in soil. Rorison and Clarkson report that the reduced nutrients result from preciPitation of phosphorus by aluminum in the soil.4,5 Indirect impacts of low soil pH include impaired nitrification (microbiological conversion of ammonia to nitrate) and attack of soil-borne pathogens on plants.6 Extremely acid reactions (pH < 4.0) render land treatment of oily saline wastes difficult, because the addition of salt promotes hydrolysis of iron and aluminum acidity, which increases the activity of hydrogen ions and further lowers the soil pH. Disruption of the carbon and nitrogen cycle reduces or extinguishes the biological action necessary for land treatment of TPH's. Low-pH soils exist in oil provinces of China, North America, and South America. Observations by the authors reveal dark red (iron) fluid seeps on slopes adjacent to closed drilling Pits in South America. This indicates soil pH < 3.5. Sparling developed solubility curves showing that ferric iron causes no toxicity problem at pH > 3.5. Aluminum and manganese are generally not a factor above pH 5.0.8 Most drilling wastes are strongly alkaline (pH > 10) and provide a beneficial neutralizing reaction when mixed with acid soils. However, most drilling Pits are closed by dewatering and burial.9 Thus, the wastes are not mixed with the acid background soil to effectuate an increased pH admixed soil. The concept of the treatment discussed in this paper is based on adding lime reagent to oily drilling waste before combining the waste with the acid soil. Typically, agricultural lime is added to soils in the form of finely ground calcite, CaCO3, or hydrated lime, Ca(OH)2. We selected hydrated lime for the present study because it yields an initially higher pH on reaction with water and a more rapid rate of reaction. Materials and Methods Drill Cuttings. Study materials, consisting of a mixture of drilling mud and cuttings, were collected in eastern Oklahoma during drilling operations conducted in November 1999. The drilling waste mixture used in the study was composed of 12.6% fuel oil, 11.2% water and 76.2% solids. Fuel oil was measured as, first, TPH by infrared spectroscopy (TPH-IR) using EPA Method 418.1, second, oil and grease using EPA Method 9071B; and third, diesel-range organics (DRO) using EPA Method 8015B. The unweathered values for TPH-IR, oil and gas and DRO were 12.6%, 12.0%, and 11.6%, respectively. The pH and salinity of the drilling waste were determined for a 1:1 solid/water extract prepared from waste solids dried at 350°C and ground to pass a 2-mm mesh sieve. The pH of the drilling waste measured 7.78. Salinity was measured as specific electrical conductance (EC), yielding a value of 21.9 mS/cm. Treatment Soil. The soil used in the lime treatment study was a Lufkin fine sandy loam (Vertic Albaqualfs). This soil was from an unimproved pasture located in Brazos County, Texas, and representative of the Ap horizon (0 to 18 cm). Select physical and chemical properties of the treatment soil are listed in Table 1. Experimental Design. Treatments consisted of four lime application levels (0, 10, 20, and 50% by total weight) and three waste-solids-to-soil application ratios (1:1, 1:2, and 1:4) superimposed on sterilized and unsterilized soil. Sterilization consisted of oven drying at 105°C for 48 hours. The intent of sterilization was to substantially reduce microbial populations of the soil without altering the organic matter content of the receiving soil. The drilling wastes were treated with lime by adding 30 g lime to 270 g waste solids (10%), 60 g lime to 240 g waste solids (20%), and 150 g lime to 150 g waste solids (50%). Neat (0% lime) and lime-treated drilling-waste solids were then added to sterilized and unsterilized Lufkin soil at a mix ratio of 1:1 (50 g waste solids:50 g soil), 1:2 (33.3 g waste solids:66.6 g soil), and 1:4 (20 g waste solids:80 g soil). Soil moisture at 22.7% was taken into consideration when adding unsterilized soil to keep the dry-weight equivalency the same as the sterilized soil. The waste/soil mixture was placed in a shallow dish microcosm and water added to yield one treatment moisture level of 35% to initiate the experiment. The mixtures reacted under laboratory conditions for 120 days, the time allotted for the experiment. Water was added daily to maintain the 35% moisture equivalent. Chemical Analyses. Soil samples were collected from each microcosm at the conclusion of the experiment and analyzed for moisture, pH, EC, and TPH. The pH and EC were measured on a 1:1 treated soil/water extract using EPA Methods 9045 C and 9050 A, respectively. Test parameters were subjected to an analysis of variance (ANOVA) to evaluate treatment effects as sources of variation.
-
Observed Contaminant Migration from an Instrumented Reserve Pit
All Days, 2000Co-Authors: Lloyd E. Deuel, George H. HollidayAbstract:Abstract A 3.3-meter deep fresh water drilling fluid Reserve Pit was instrumented to determine migration of contaminates from the Pit during drilling and after Pit closure. The ability to predict impacts from earthen drilling Pits has become important, due to the recognized potential for an adverse impact on soil and water resources. The results of the field study allow operators to control chemical composition of Pit wastes to prevent contaminants from migrating from an active or closed Pit. To the best of our knowledge, no other Reserve Pit has been evaluated by instrumentation installed a priori to evaluate the environmental impact of Reserve Pits. The Pit was equipped with neutron probe access tubes, barrel size lysimeters, vacuum extraction moisture cups and gypsum resistively blocks at 4 stations within the Pit perimeter. Ground water monitoring wells, and post closure soil borings were used to assess the long-term affects of the earthen Pit use and onsite disposal of the Pit waste solids on soil and ground water resources. The soil moisture and chemical data generated during the 2-year field study was evaluated statistically utilizing analyses of variance (ANOVA). Soil water monitoring during Pit use showed the soil profile below the Pit remained unsaturated under the influence of a 3.3-m head of Pit fluid. This demonstrated the clay gels [spud mud] serve as a Pit surface sealant and retards percolation of fluids from the Pit. Chlorides were retained in the Pit by an anion exclusion mechanism. This mechanism remained stable and the exclusion volume functional in Pit solids having Saturated Paste Electrical Conductivity [SPEC] of = 24 mmhos/cm. Post closure data show clean closure of the study Pit and no alteration of intended land use (improved pasture) or adverse impact to the natural environment. Introduction This field study, sponsored by the Petroleum Environmental Research Forum [PERF], assess the impact to ground water and soil of fresh water drilling fluids contained in an earthen Reserve Pit. Nearly all Reserve Pit studies reported in the literature concentrate on after-closure affects (Murphy and Kahew, 1984). Accordingly, environmental effects caused by the Pit contents must be inferred by extrapolating post-closure information. The instant study measures the real-time environmental effects of a Reserve Pit from construction, use and through 2-years of post-closure monitoring. Reserve Pits are a practical method of storing spent drilling fluids, and drill cuttings. Drilling fluids serve a variety of purposes, the most important being, controlling formation pressures. Typically, drilling fluids fall into four categories:Fresh water base - where the continuous phase is fresh waterSalt water base - where the continuous phase is salt waterOil base - where the continuous phase is hydrocarbon or mineral oilEmulsion base - where an oil-in-water or water-in-oil emulsion is the continuous phase Fresh water base drilling fluids represent 85 to 90 percent of the total drilling fluids in use, because of low toxicity, ease of treatment, low temperature stability and low cost. Except for areas where massive salt deposits exist, fresh water is the drilling fluid of choice for shallow drilling.
-
Measurement of Solute Transport from an Earthen Reserve Pit During Drilling and Post Closure Operational Phases: Part I. Site Characteristics and Experimental Design
All Days, 1999Co-Authors: Lloyd E. Deuel, Shawn Hokanson, George H. HollidayAbstract:This paper was prepared for presentation at the 1999 SPE/EPA Exploration and Production Environmental Conference held in Austin, Texas, 28 February-3 March 1999.
Andrew K. Wojtanowicz - One of the best experts on this subject based on the ideXlab platform.
-
Louisiana Orphaned Reserve Pit Cost Assessment
All Days, 2007Co-Authors: Adam Michael Lewis, Travis Michael Webre, Andrew K. WojtanowiczAbstract:Abstract In the oilfield, a Reserve Pit is any site (usually an earthen-Pit) that is used for the collection of used drilling fluid. These sites must be closed (cleaned up and disposed off) in order to meet certain federal and local requirements. The costs associated with this are directly affected by environmental regulations, contamination levels, geographic/ecological location, and distance to an approved disposal site. Since 1983, states have had the option to set unique standards for Reserve Pit closure. Louisiana enacted its standards in Act 404 of the 1993 Regular Legislative Session. The work presented in this paper can be used to estimate the cost to close a single, unique Reserve Pit in order to meet federal and Louisiana state regulations for Reserve Pit closures. State approved contractors where contacted to obtain closure cost estimates for comparison with historical closure costs obtained from government records. Relationships for cost versus size and contamination levels were established. A computer program facilitates the cost estimation procedure. In the program, the state and federal regulations, and the cost estimates for various closure techniques have been compiled into a Visual Basic-driven Excel spreadsheet. All an individual user must do to generate a cost estimate for a particular Reserve Pit is to input data from samples taken from that Pit. The study has shown that cost prediction is reasonably accurate for "normal" Reserve Pits that require little or no chemical remediation. However, when serious chemical remediation is needed for Pits contaminated with salt or oil, the prediction loses precision due to the large number of variables and wide range of costs associated with those variables. This work has become of paramount importance for the State of Louisiana because there are currently over 1,500 "orphaned" Reserve Pits in Louisiana, i.e. sites for which no liable party/company can be found. The State has had to assume financial responsibility for closing these orphaned Reserve Pits using the statewide tax on natural gas production. The State has expressed serious interest in understanding the scope and significance of the problem that they are currently dealing with. Introduction After several consultations with the Department of Natural Resources (DNR), we decided to research Reserve Pit closures techniques in order to create an effective method for determining the closure cost. After researching Reserve Pit classifications, contaminants, operational requirements, monitoring programs, and closure techniques, we solicited operators and construction contractors in order to prioritize cost affecting parameters. Our primary goals were to allow an individual user to estimate the closure cost for a single, unique Reserve Pit and to provide DNR with an estimate for the total cost to close all of the state's known orphaned Reserve Pits. These goals were achieved in the form of a visual basic program. The input spreadsheet allows any user to enter parameters for a unique Pit and the program in turn generates a cost estimate. Historical data was then acquired and we discovered that 75% of Louisiana's orphan Reserve Pits were allowed to be bulldozed, minimal cost closure, due to acceptable contamination levels. Only 18% of the Pits in the last 6 years needed chemical remediation and 7% of the Pits required disposal. Using the historical data on Reserve Pit closure costs, we determined that the statistical distribution of closure costs is lognormal with the minimal closure cost being the most likely. This allowed us to construct a cumulative probability plot. This plot was used in conjunction with an estimate of the current number of Reserve Pits in the state to determine the minimum, median, and maximum closure costs for Louisiana.
-
Environmental Control of Drilling Mud Discharge Through Dewatering in Cold Weather Climates: Effect of Ambient Temperature
All Days, 1991Co-Authors: Andrew K. WojtanowiczAbstract:Abstract The paper presents results of an experimental study into the effect of drilling mud temperature upon the dewatering performance. Three temperature ranges were considered: performance. Three temperature ranges were considered: from flowline temperature to room temperature, from room temperature to freezing point, and the freeze (-4 deg. F)/thaw (54 deg. F) cycle. The tested drilling fluids included unweighted and weighted fresh water muds and a weighted salt water mud. A sealed laboratory batch reactor was used in the experiments to prevent rapid vaporization of separated water at temperatures above 140 deg. F. Also, ice or ice-salt baths were utilized for deep freezing. The dewaterability (net water removal) was measured with a bench-top plate press under constant expression pressure 30 psi. The freeze/thaw treatment greatly enhanced dewaterability by releasing 34–39% by volume of the mud water. Mechanical dewatering followed; it required half the chemicals and released an additional 36–43% of water. The process proved to be very effective, reducing waste mud process proved to be very effective, reducing waste mud volume by 64–72%. It also seemed to be well-suited for the Arctic with its natural freeze/thaw cycles. The results of experiments at temperatures above 70 deg. F showed that there is little advantage to dewatering hot drilling mud diverted from active system. A 10% increase of water removal was observed above 140 deg. F. The experiments at temperatures below 70 deg. F showed that in cold weather climates the waste drilling mud diverted from active system should be dewatered when its temperature is still above 40 deg. F. Otherwise, more chemicals will be needed for separation enhancement or the dewatering process will become entirely ineffective. Introduction The dewatering process has become increasingly popular in oilfield drilling practices. Its first field applications in the early 1980's were related to the oilfield Pit closure procedures, where drilling waste from Reserve Pits was procedures, where drilling waste from Reserve Pits was processed by portable dewatering units. In this application, processed by portable dewatering units. In this application, the dewatered Pit solids can be directly disposed on-site using burial, trenching, or land treatment practices, or they can be initially solidified to prevent any potential leaching of toxicants. The dewatering effluent may be either directly disposed to the land or surface waters, or, when the effluent limitation guidelines are not met, can be injected underground. Several configurations of the Pit dewatering processes commercially offered to the oilfield petroleum industry in the US and abroad have been reviewed in the literature. Later, the dewatering process was used as part of the active mud processing for separation and recycling of the mud water phase to minimize the drilling waste discharge volume. The dewatering of circulating active muds proved to be more difficult than the dewatering of Reserve Pit sludges, particularly when the mud systems contained high particularly when the mud systems contained high concentrations of surface-active solids after being heavily treated with the suspension stability-control agents, as is the case for dispersed muds. DesPite disadvantages, the dewatering of active mud offered an attractive alternative to drilling a well without a Reserve Pit, particularly in zero-discharge areas. Another hypothetical advantage of this process is that the high temperature of the circulating drilling process is that the high temperature of the circulating drilling mud may enhance its chemical destabilization prior to dewatering so that the cost of chemicals may be reduced in comparison to the treatment of a cold waste mud from the Reserve Pit. P. 147
Diana Garcia - One of the best experts on this subject based on the ideXlab platform.
-
continuous flow separation system recovers oil from Reserve Pit fluids
2009Co-Authors: Katerina Newman, Karen Mccosh, Alan Gilmour, Diana GarciaAbstract:Lined Reserve Pits are widely used for storage of drilling discharges during land drilling operations. In the areas where operators predominantly utilize invert-emulsion drilling fluids such Pits may contain significant amounts of hydrocarbon, solid material including colloidal particles and some free-water. Weak oil-in-water emulsions might also be present. Recovery of both, the hydrocarbon and aqueous, fractions of this Reserve Pit fluid can be achieved by demulsifying the fluid and separating fine and colloidal particles from the oil medium. The results are environmentally and economically beneficial. By optimizing Reserve Pit fluid treatment management practices on location, the volume of waste and the number of Reserve Pits can be reduced. Reclaimed hydrocarbons from the Reserve Pit can be recycled and used as a base for new drilling fluids. A continuous-flow closed-loop process has been developed to treat the Reserve Pit fluid so as to recover clean oil. The Reserve Pit material is treated with a demulsifying surfactant and a flocculating polymer which converts the solids and some of the water phase into a flocculated mass which can be separated using a standard oilfield centrifuge. The remaining water and oil phases exit the centrifuge as liquid effluent and are collected. The chemical de-emulsification is sufficient to allow the oil and water phases to separate under gravity and the top oil layer can then be recovered to a separate vessel for recycling or reuse. This technology has been tested at an operational location in the US and results from this successful operation will be presented. It will be shown that this chemically enhanced separation system significantly improves solids and water removal from the Reserve Pit fluid compared to centrifugation alone. Chemical treatment at <1 vol % was sufficient to recover clean oil which contains less that 3% by volume water and solids and is suitable for reuse. This new approach provides an innovative solution to Reserve Pit fluid treatment and management for land drilling operations, allowing effective treatment of oil-containing Pit fluids for environmentally responsible waste reduction, Pit cleanup and oil recycling.