Air Injection Wells Research Articles

Effect of landfill in-situ aeration with novel air amplifier: A case study

Landfill aeration may cause economic problems due to the amount of power consumed by blowers. Thus, this study proposes the use of an air amplifier to reduce the power consumption of air injection into landfills. The developed air amplifier is an aerodynamic device that induces a large amount of airflow using a small quantity of compressed air caused by the Coanda effect. Field experiment results demonstrated that the use of the air amplifier reduced power consumption by at least 90% and showed an air amplification effect of approximately 3.5 times compared with existing in-situ aeration systems. After aeration, the methane (CH<sub>4</sub>) reduction efficiency was 90.3%. The CH<sub>4</sub>/CO<sub>2</sub> ratio was 0.12 (0.06–0.25) on average, and the CH<sub>4</sub>/CO<sub>2</sub> ratio decreased as the oxygen concentration increased. Thus, the air amplifier is a low-cost solution for landfill aeration systems. In addition, aeration using existing leachate collection and drainage pipes was found to be more economical than air injection using air injection wells. However, despite the air injection, approximately 20% of organic carbon was decomposed anaerobically. The CH<sub>4</sub>/CO<sub>2</sub> ratio range of 0.56–0.90 was presented as a criterion for categorizing a landfill as semi-aerobic.

Unveiling the mechanisms of in-situ combustion of post-steam driven heavy oil by electric heating method induced auto-ignition

Ignition design of air injection wells is the crucial factor to a successful in-situ combustion. In this paper, experimental studies were carried out on post steam flooding wells at JIN-91 of Liaohe oilfield for improving ignition success rate. The experiments were conducted by a high temperature-pressure ignition device specifically designed for in-situ combustion, and the effects of various parameters were investigated by factorial experiments. The results showed that the ignition temperature was reduced and the ignition time was shortened due to three factors: heating temperature, reservoir pressure, and clay minerals. When heating temperature exceeded 360 °C, experimental pressure was higher than 4.0 MPa, and 10% of montmorillonite clay was added, the crude oil samples could be ignited rapidly. According to the factorial results, the most effective method to shorten ignition time is by increasing heating temperature, the safest method to reduce crude oil spontaneous combustion temperature and to shorten ignition time is by applying clay minerals, and reservoir pressure is the key factor for safety operation during ignition operation. These results will provide experimental theoretical guidance for high efficiency ignition, process optimization, and safe implementation of crude oil reservoir, they also will deliver tech support for the high efficiency operation of in-situ combustion.

A new description method of the position of combustion front in dry linear fire flooding process

Abstract The description methods of combustion front are required to be fast and accurate for in-situ combustion (fire flooding), and the current methods can't fully conform that requirement. However, the description method based on conventional data monitoring is a way to solve this problem. The experimental results of dry combustion indicates that the position of combustion front has a nearly linear correlation with the total acid numbers (TAN) of oil produced for in-situ combustion (ISC). Meanwhile, the tendency of pressure variation between neighboring air injection wells can determine the state and the time of combustion chamber connected in linear ISC process. Therefore, based on the relationship between TAN, injection pressure and combustion front, the acid numbers-pressure(ANP) method is established，which is suitable for dry linear fire flooding. Further, this method is applied to the calculation of the position of the combustion front in HQ1 ISC pilot area in Xinjiang over the years. Compared with other methods, the ANP method can rapidly calculate the position of combustion front and confirm the connectivity of combustion chamber. In addition, the combination of the ANP and other method is a good solution to confirm the position of combustion front for dry linear ISC process.

Comments on: The flow and heat transfer characteristics of compressed air in high-pressure air injection wells [Arabian Journal of Geosciences (2018) 11: 519

High pressure has been widely used in the petroleum industry. The commended paper presented a model that can be used to simulate air flow in a vertical wellbore. The novelty and usefulness of the model is good, and the paper deserves to be published in the Arabian Journal of Geosciences. However, we pointed out some critical points that should be noticed by the authors as well as the following researchers who are involved in this area. The comments will show usefulness in pointing out future research direction in wellbore modeling.

The flow and heat transfer characteristics of compressed air in high-pressure air injection wells

High-pressure air injection (HPAI) is a significant enhanced oil recovery (EOR) technology of light oils especially in deep, thin, low-permeability reservoirs. The flow and heat transfer behaviors of compressed air in wellbore is essential to maximize performance of air in EOR. Due to strong compressibility of air and high injection pressure, wellbore temperature and pressure are greatly affected by friction and gas compression. However, the available models of wellbore flow and heat transfer are only accurate for thermal fluid, such as saturated steam and superheated steam, injected at relatively low pressure and high temperature. In this paper, a novel model is proposed to characterize wellbore pressure and temperature distribution for HPAI wells with consideration of dynamic behaviors of injected air. Flow and heat transfer in depth direction are coupled with air properties by iterative technique, and heat transfer in radial direction is treated as steady state in wellbore and transient state in formation. The mathematical model is solved by employing finite difference method and it is validated by field data. Then, integrated analyses of flowing pressure, heat transfer mechanism, and interaction between pressure and temperature are conducted. Results indicate that (1) as well depth increases, temperature difference between formation and air tends to become constant, and the radial heat transfer tends to reach an equilibrium state. The higher the flow rate is, the deeper the equilibrium depth is. (2) Air temperature is dominated by heat transmission from formation at low flow rates and dominated by frictional heat and gas compression effect at high flow rates. Fictional heat begins to affect air temperature at an injection rate beyond the critical value, while gas compression effect can increase air temperature in the whole calculated injection rate range. (3) Interaction between wellbore temperature and pressure is mainly achieved by altering air density. The effect of injection pressure on air temperature can be negligible, while the influence of injection temperature shows strong dependency on injection rate.

1,4‐Dioxane Soil Remediation Using Enhanced Soil Vapor Extraction: I. Field Demonstration

Abstract1,4‐Dioxane is totally miscible in water, sequestering in vadose pore water that can serve as a source of long‐term groundwater contamination. Although some 1,4‐dioxane is removed by conventional soil vapor extraction (SVE), remediation is typically inefficient. SVE efficiency is hindered by low Henry’s Law constants at ambient temperature and redistribution to vadose pore water if SVE wells pull 1,4‐dioxane vapors across previously clean soil. It was hypothesized that heated air injection and more focused SVE extraction (“Enhanced SVE” or XSVE) could increase the efficiency of 1,4‐dioxane vadose treatment, and this new process was tested at former McClellan Air Force Base, CA. The XSVE system had four peripheral heated air injection wells surrounding a 6.1 m × 6.1 m × 9.1 m deep treatment zone with a central vapor extraction well. After 14 months of operation, soil temperatures reached as high as ~90 °C near the injection wells and the treatment zone was flushed with ~20,000 pore volumes of injected air. Post‐treatment sampling results showed reductions of ~94% in 1,4‐dioxane and ~45% in soil moisture. Given the simplicity of the remediation system components and the promising demonstration test results, XSVE has the potential to be a cost‐effective remediation option for vadose zone soil containing 1,4‐dioxane.

In-well air sparging efficiency in remediating the aquifer of a petroleum refinery site

Air sparging represents an innovative groundwater remediation technology, which has been proved to be capable of restoring aquifers that have been polluted by volatile and (or) biodegradable contaminants, such as petroleum hydrocarbons. This paper presents the design, the installation, and the pulsed operation of an in-well air sparging system at the site of a Greek petroleum refinery. The geographical position, the hydrologeoly, and the contamination features of the chosen study area develop special conditions that, along with the fact that the existing refinery is still active, greatly determine the applicability and the effectiveness of the specific technology. The area that was used for the application of the technology covered almost 600 m2 and included five air injection wells and four additional monitoring wells. The pulsed operation of the installed system lasted about 5 months and the results of frequent groundwater sampling and analysis indicate an important decline in total petroleum hydrocarbons (TPH) and benzene–toluene–ethylbenzene–xylene (BTEX) concentrations (up to 99%). However, prior to any attempt to expand the application of air sparging within the facilities of the refinery, special attention should be given to the eccentricities of the site and the ability of the technology to confront more persistent contaminants, such as methyl tertiary-butyl ether (MTBE).

Controlling steam flood migration using air injection wells

Plumes of contamination emanate from nonaqueous-phase liquid sources as its constituents slowly dissolve into passing groundwater. For a large, well-characterized source, an aggressive technology such as steam flooding can accelerate cleanup. Steam is injected through a series of wells within and around a source area, and the steam zone grows radially around each injection well. The steam front drives the contamination to a system of groundwater pumping wells in the saturated zone and soil vapor extraction wells in the vadose zone. The movement of steam in the subsurface is governed primarily by soil heterogeneity and gravity. Steam is buoyant in groundwater and tends to migrate upward unless injected below a continuous confining layer. Groundwater pumping rates and vacuums typical of steam flooding are generally low compared to the steam injection rate and pressure and have limited influence over the lateral growth of the steam zone. To overcome these limitations, a system of air injection wells can be used to direct the steam zone growth. This paper presents results of sand-box experiments using air injection to prevent the outward growth of a steam zone between extraction wells with a discontinuous confining layer limiting the upward migration of steam. These experiments were numerically modeled with the multiphase nonisothermal code T2VOC. When confined vertically, the experiments and modeling show that outward migration of the steam front can be effectively controlled by placing air injection wells opposite steam injection wells. This technique can direct steam zone growth toward difficult access sources and away from areas where steam is not desired. Control of a proposed full-scale steam flood of the M-Area settling basin at the Savannah River Site was modeled using this method and the results are presented in this paper.

Cost‐effective strategy for installation and operation of a bioventing system to remediate jet fuel contamination beneath the former refueling apron at Griffiss Air Force Base, New York

AbstractA bioventing system was designed and installed beneath the former refueling apron, Apron 1, to enhance biodegradation of residual jet fuel‐contaminated soils at the former Griffiss Air Force Base (GAFB) located in Rome, New York. The innovative reuse of existing fuel supply lines for air injection has allowed for the continued use of the 29‐acre apron surface, while at the same time providing for aeration and remediation of approximately 60,000 cubic yards of petroleum‐contaminated soil beneath the apron. Additionally, use of the fuel supply lines eliminated the need for costly saw cutting and excavation of the 18‐inch concrete apron surface, or use of horizontal drilling techniques for installation of piping to the air injection wells, and resulted in a savings of approximately $150,000. Installation costs were further reduced by installing aboveground piping to air injection wells located at the former lateral control points in areas isolated from the biopile operations and maintenance activities. Total remediation costs for contaminated soil beneath the apron are approximately $10 per cubic yard of treated soil.The former refueling apron is currently used for the ex situ biopile treatment of contaminated soils collected from throughout the base. The arrangement of the existing biopiles, and the need for additional biopiles on the apron in the future, necessitated the use of underground piping to supply air to injection wells located at former refueling hydrants. In order to facilitate uninterrupted remediation of the biopiles, existing underground fuel supply pipelines that were cleaned and closed in place during the deactivation of the refueling apron in 1996 were utilized to supply air from the edge of the refueling apron to the air injection wells.This remediation strategy, which maximizes the use of available space by utilizing both in situ and ex situ treatment technologies, will significantly reduce the period of time required for remediation of contaminated soil at the former GAFB and provides a cost‐effective approach to attaining beneficial reuse of the site. © 2003 Wiley Periodicals, Inc.

Design of Dry Barriers for Containment of Contaminants in Unsaturated Soils

AbstractA dry barrier consists of a laterally continuous soil layer that is dried by air flow. Dry atmospheric air is passed through a soil layer (preferably of a coarse texture). accumulates water vapor, then emerges from the formation as moist air. Removal of soil moisture limits or prevent downward water movement. Drying a soil layer with air is possible when atmospheric air contains less water vapor than soil pore gas. The design of an effective dry barrier is highly site dependent and requires knowledge of the site geology, of the extent of the contaminant plume, and climatic conditions. Climatic conditions at the site are important in two ways: (1) the efficiency of atmospheric air in drying: soil depends on its absolute humidity: and (2) the amount of infiltration from precipitation influences how much water has to be removed from the soil to maintain a dry barrier. The size of the barrier, combined with the climatic conditions, determines the air flow required to maintain the system. while the hydraulic characteristics of the soils determine the location and design of air injection and extraction wells. The electric power rate structure must be known to calculate operating costs. The principal factors which determine the feasibility of a dry barrier include: (1) the climate at the site and, most importantly, low‐absolute atmospheric humidity during much of the year; (2) a substantial unsaturated zone; and (3) the ability to circulate air through the unsaturated zone. The amount of initial soil moisture in the layer through which air is circulated may be an important factor in the feasibility of a dry barrier. A design study is presented that illustrates the trade‐offs between high capital costs of constructing a large number of air circulation wells vs. the high operating costs required to pump large volume of air over long distances through fewer wells. This study found that, under conditions similar to those in many arid regions, a dry barrier may be a technically and economically viable method of providing temporary waste containment.

Three‐Dimensional Experimental Testing of a Two‐Phase Flow‐Modeling Approach for Air Sparging

AbstractAir sparging has been used for several years as an in situ technique for removing volatile compounds from contaminated ground water, but few studies have been completed to quantify the extent of remediation. To gain knowledge of the air flow and water behavior around air injection wells, laboratory tests and model simulations were completed at three injection flow rates (62, 187, and 283 lpm) in a cylindrical reactor (diameter ‐ 1.2 m, depth = 0.65 m). Measurements of the air flux distribution were made across the surface of the reactor at 24 monitoring locations, six radial positions equally spaced along two orthogonal transects. Simulations using a multiphase flow model called T2VOC were completed for a homogeneous, axisymmetric configuration. Input parameters were independently measured soil properties. In all the experiments, about 75 percent of the flow injected exited the water table within 30 cm of the sparge well. Predictions with T2VOC showed the same. The averages of four flux measurements at a particular distance from the sparge well compare satisfactorily with T2VOC predictions. Measured flux values at a given radius varied by more than a factor of two, but the averages were consistent between experiments and agreed well with T2VOC simulations. The T2VOC prediction of the radial extent of sparging coincided with the distance out to which air flow from the sparge well could not be detected in the reactor. The sparging pattern was relatively unaffected by the air injection rate over the range of conditions studied. Changes in the injection rate resulted in nearly proportional changes in flux rates.

Simulation of Bioventing for Soil and Ground-Water Remediation

A three-dimensional finite difference model for simulation of bioventing is presented. The model incorporates three-phase (gas-water-organic) flow with equilibrium interphase mass transfer and dispersive transport of organic compounds, oxygen, and carbon dioxide. Growth of microorganisms, substrate and oxygen consumption, and carbon dioxide production due to microbial activity are included. Biodegradation limitations due to both substrate and oxygen availability are modeled using the dual Monod formulation. The model is applied to predict the fate of a spill of toluene in the vadose zone under natural conditions and with various configurations of air injection and vapor extraction wells. Configurations of wells are determined that maximize biodegradation and minimize both the amount of toluene withdrawn in extraction wells and the amount lost to the atmosphere.

Application Of Fluid Analyses To The Operation Of An In Situ Combustion Pilot

Abstract This paper reports the interpretation of the results from an extensive field fluids monitoring program which supported the operation of the Petro-Canada/ AOSTRA heavy oil in situ combustion pilot at Kinsella, Alberta. Produced gas analyses are discussed in terms of confirmation of reservoir ignition, monitoring the progress and efficiency of the burn, safety considerations and the extent of air propagation in the reservoir. Fireflood indicators in the produced water indicated the proximity of the/ire with respect to individual wells, as well as providing insights into the chemical processes occurring during combustion. Changes in oil composition indicated which wells were most influenced by low temperature oxidation, distillation and thermal cracking of the oil. An over-all assessment of the data, in conjunction with operational parameters, demonstrated that fireflood indicators in the produced fluids can be used over the entire pilot operation to monitor the advance of the fire/rant and to estimate the location of the fire with respect to production wells. Introduction Steam-based thermal recovery strategies have found widespread application. However, some shallow reservoirs with a thin net pay zone and containing viscous oil are currently best exploited using an in situ combustion process. Operators such as Pan Canadian Petroleum(1). Amoco(2). Husky (3), General American Oils(4), and Petro-Canada(5) have reported on the complexities of operating fireflood projects in Alberta. The Kinsella Heavy Oil In Situ Combustion Project (KHOPD) was a joint venture between Petro-Canada Resources and the Alberta Oil Sands Technology and Research Authority (AOSTRA). The pilot site was located approximately ZOO kmsoutheast of Edmonton, Alberta (Fig. I). The air pattern originallyonsisted of four air injection wells (BI-I, BI-2. BI-3 and I-4), five production wells (BP-1, BP-2, BP-3, BP-4 and BP-5) and three observation wells (BO-I, BO-2 and BO-3). The air attern was subsequently modified with the addition of three production wells (BP-6, BP-7 and BP-8) and two observation wells (BO-4 and BO-5). The four wells BP-I, BP-6, BP-7 and BP-8 essentially yielded an inverted five-spot around the air injector BI-4 (Fig. 2). The produced fluid compositions from three additional wells (AP-2, AP-4 and AP-5), located some distance from the air pattern (Fig. 2), were also monitored. Dry combustion was carried out at KHOP-D for approximately two years. The wet combustion phase commenced in August 1983 with intermittent water injection into BI-4 for the purpose of scavenging heat from the burned zone and transmitting this heat(in the form of steam) to the oil bank in front of the combustion zone. To assist with the operation of this pilot, in understanding the reservoir behaviour and in the design of subsequent projects, an extensive fluids analysis program was establishedto monitor the composition of the produced fluids. Regular sampling and analysis of produced gas, oil and water from as many as eleven production wells continued for approximately 3 and a half years. Gas and water samples were generally analyzed on a weekly basis, while oil samples were analyzed twice per month. Indications that the firefront was approaching a particular well often necessitated more frequent analysis.

Heavy-Oil Recovery by In-Situ Combustion - Two Field Cases in Rumania

Cadelle, C.P., Inst. Francais du Petrole Burger, J.G., Inst. Francais du Petrole Bardon, C.P., Inst. Francais du Petrole Machedon, V., Research and Design Inst. for Oil & Gas Carcoana, A., Research and Design Inst. for Oil & Gas Petcovici, Valentin, Research and Design Inst. for Oil & Gas Summary Laboratory and field results are presented for two Rumanian fields: Suplacu de Barcau and Balaria. Insitu combustion is in the industrial stage at Suplacu de Barcau (38 air-injection wells), and the Balaria project (now 5 air-injection wells) is being expanded. Data given include air injected, oil produced, cumulative air/oil ratio, and composition of gas produced. These data, with measurements of temperature and thickness burned, have been used to follow and control the process. Introduction The depletion of easily producible oil resources is giving increasing importance to the considerable accumulations of heavy oil scattered throughout the world. Recovery using conventional production techniques is limited, however, and laboratory research and field testing have been conducted in an effort to develop more efficient recovery methods - mainly steam injection and in-situ combustion.A cooperation agreement was signed in Sept. 1969 between the Inst. Francais du Petrole (IFP) and the Ministry of Mining, Petroleum, and Geology of Rumania, representing the Research and Design Inst. for Oil and Gas (ICPPG), to carry out joint research and development on thermal recovery methods.Since this agreement was signed, IFP and ICPPG have studied the various aspects of oil recovery by insitu combustion. They have conducted laboratory work and field applications in a wide variety of reservoirs containing heavy or conventional oil, thereby gaining broad experience in the use of the insitu combustion technique.This paper outlines and describes their joint endeavors, concentrating particularly on two in-situ combustion field operations under way in Rumania. Feasibility of In-Situ Combustion Screening criteria have been developed through theoretical research and laboratory experimentation to determine the suitability of a given reservoir for insitu combustion. It has been found that shallow reservoirs containing heavy oil are often promising candidates. Once a reservoir is chosen, in-situ combustion is carried out in three phases, as illustrated in Fig. 1: ignition, process implementation, and measurements and interpretation.Specific field applications have been conducted by ICPPG and IFP on the basis of this methodology and are described, along with the base studies, in this article. Ignition If sufficient heat is released by the oxidation of the oil under reservoir conditions, spontaneous ignition will occur a few days after air injection is begun.To determine the probability of spontaneous ignition, the oxidation rate of the oil under reservoir conditions was measured in the laboratory.Oil/sand mixtures are placed in a cylindrical vessel with a metal screen so that the oxygen in the surrounding gas has easy access to the crude. The vessel is placed in the pressure cell (Fig. 2). The oxidation rate, calculated from the change in the oxygen content of the air in the cell, is determined at temperatures between 50 and 140 degrees C (122 to 284 degrees F) and at pressures between 3 and 10 MPa (435 to 1,450 psia).A numerical model then is used to calculate the temperature changes vs. time and the space coordinate when air is injected into the formation. The ignition delay is considered as the time required for the maximum temperature in the investigated zone to reach the ignition temperature (210 degrees C or 410 degrees F). It appears that spontaneous ignition is likely to occur when the reservoir temperature is above 55 to 60 degrees C (131 to 140 degrees F). JPT P. 2057^

Performance of the Fry In-Situ Combustion Project

A pilot operation, reported on at the 1964 SPE Annual Fall Meeting, has been converted into an expanded field operation. This updates the earlier report and concludes that, although the economics is not favorable, the project continues to be a technical success and does show a day-today project continues to be a technical success and does show a day-today operating profit. Introduction The Fry combustion project in Crawford County, Ill., changed from a pilot test to a field-wide operation at the beginning of 1964. This paper will cover the field operation and production behavior for the total project from the ignition of the pilot (Oct., 1961) to the project from the ignition of the pilot (Oct., 1961) to the present. Information about the operations and present. Information about the operations and performance of the pilot was presented by Clark et al. performance of the pilot was presented by Clark et al. Reservoir geology was discussed by Hewitt and Morgan. Additional production data from the expanded operation were given by Poettmann et al. to illustrate some of the technology involved in the analysis of the combustion process, particularly in light oil reservoirs. The main purpose of this paper is to update the production histories through 1968 and to show the effect production histories through 1968 and to show the effect that various procedures have had on production. Reservoir Properties The Fry reservoir has been described as a lenticular, southwest trending Robinson sandstone body of Lower Pennsylvanian age. It is of fluvial origin and part of an extensive complex of river sediments. Fig. 1 shows the present version of the net sand isopachous map, which has been revised as new wells were drilled during the expansion program. Portions of the reservoir, mainly to the west, are not shown since they have not been affected by combustion. The four air injection wells are located to show their relationship with respect to the reservoir geometry. The reservoir sand is usually fine- to mediumg-grained, with quartz, feldspar, and muscovite as the predominant minerals. Accessory minerals include kaolinite, illite, calcite, siderite, pyrite, and carbonized plant fragments. The sand can be subdivided into four distinct structural units. A zone Small-scale, trough-shaped ripple structures. Very-fine to fine-grained. Generally less than 5 ft thick. Maximum thickness - 11 ft. B zone - Cross-stratification sets ranging from 0.5 to 4 ft thick (average, 1 ft). Fine to medium grained. Occurs over entire reservoir area. Greater than 30 ft thick in some areas. C zone Mixed sandstone-shale laminae lithology. Individual sand layers 0.1 to 0.5 ft thick. Medium grained. Occurs in central portion of reservoir, not extending to NW or SE boundaries, not quite extending to Well AI-2. Greater than 20 ft thick around and somewhat north of Well AI-1. M zone Massive, structureless sandstone. Medium grained. Occurs only around Well AI-2. Very small overlap between areas of the C and M zones. twelve feet noted in one well. This zone has been detected since the original publication. Table 1 is a summary of average core analysis data from seven wells spread throughout the field. These data indicate that the reservoir is fairly uniform. However, core analysis permeabilities tell little of the effect of structural features on over-all permeability. The probable existence of a directional permeability due to structural or grain orientation effects has been noted previously, as have other effects of geology on previously, as have other effects of geology on reservoir performance. JPT P. 551