ISSN:0090-8312    

DOI:10.1080/00908319950014902

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Polymer flooding has been found to be an excellent method for improving oil recovery from marginal oil reservoirs with intense heterogeneity or high-producing water-oil ratios (WOR). Accurate analysis, however, must be conducted prior to deciding on a polymer flooding operation. Even though the petroleum literature has reported a set of criteria for screening oil reservoirs for polymer flooding and their qualitative analyses, rarely can one find any quantitative analysis outlining the validity of the commonly held views in the petroleum industry. This article presents a quantitative analysis of the performance of an oil reservoir subjected to polymer slug injection. Fluid and rock properties are varied in order to determine the economics of an enhanced oil recovery scheme. The reservoir parameters considered in this analysis are reservoir permeability (230-2300 md), initial water saturation (0.25-0.5), and oil viscosity (25-100 cp). In order to study the role of field operational parameters in determining the success of the polymer slug injection process, polymer viscosity (1.45-9.6 cp), rock adsorption characteristics (10-5 - 10-4 lbm lbm rock), and polymer slug size of a constant concentration (0.1-0.5 PV) are considered. The reservoir performance is represented by the behavior of oil recovery, WOR, and oil production rate. For this study, the detailed reservoir fluid and rock properties were taken from a U.S. prototype (Lower Huntington Beach Garfield zone of California). Detailed analyses indicate that the reservoir permeability is of paramount importance to determining the success of polymer slug injection in an oil reservoir. The analysis of the behavior of sandface pressure for low permeability reservoirs provides interpretation of the plugging effects observed in tight reservoirs. Finally, the numerical model results confirm the widely held view of using 0.70 pore volume injected (that corresponds to a WOR of 15), as a criterion to terminate a polymer slug injection project.

ISSN:0090-8312    

DOI:10.1080/00908319950014911

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Several strains of thermophilic bacteria were isolated from the environment of the United Arab Emirates. These bacteria show extraordinary resistance to heat and have their maximum growth rate around 60 80 C. This article investigates the potential of using these facultative bacteria for both in situ and ex situ bioremediation of petroleum contaminants. In a series of batch experiments, bacterial growth was observed using a computer image analyzer following a recently developed technique. These experiments showed clearly that the growth rate is enhanced in the presence of crude oil. This is coupled with a rapid degradation of the crude oil. These bacteria were found to be ideal for breaking down long-chain organic molecules at a temperature of 40 C, which is the typical ambient temperature of the Persian Gulf region. The same strains of bacteria are also capable of surviving in the presence of the saline environment that can prevail in both sea water and reservoir connate water. This observation prompted further investigation into the applicability of the bacteria in microbial enhanced oil recovery. In the United Arab Emirates, the reservoirs are typically at a temperature of around 85 C. Finally, the performance of the bacteria is tested in a newly developed bioreac tor that uses continuous aeration through a transverse slotted pipe. This reactor also uses mixing without damaging the filamentous bacteria. In this process, the mecha nisms of bioremediation are identified.

ISSN:0090-8312    

DOI:10.1080/00908319950014920

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

The use of a membrane in gas separation is gaining popularity and is considered to be the most prominent emerging technology in gas separation. In order to determine the effectiveness of a membrane in separating gases, it is important to have an accurate estimate of the pore size distribution. This article presents a method to estimate the pore size distribution from adsorption isotherm data. Adsorption isotherm data are used to determine the pore size distribution using both slit and cylindrical models. The theory that relates adsorption isotherm to pore size distribution is presented. The method is validated with experimental data and it is shown that both the models exhibit narrow distribution profiles.

ISSN:0090-8312    

DOI:10.1080/00908319950014939

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Energy is the most critical factor for the growth of a nation's economy. However, its use has a major impact on the environment, especially by discharging air pollutants into the atmosphere. In addition, energy production from fossil fuel, the world's most important fuel, is recently known to be the key contributor of CO2 (a major greenhouse gas) resulting in global warming problems. This article is an extension of our earlier research work to demonstrate how cogeneration concepts can be used to reduce production costs and simultaneously produce electricity, steam, as well as industrial gases such as CO2. With cogeneration, there is very little air pollution discharged into the atmosphere. We discuss a case study of an enhanced oil recovery (EOR) application.

ISSN:0090-8312    

DOI:10.1080/00908319950014948

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Carbon dioxide (CO2) separation technology can be considered to be a mature technology. However, there remains ample room for process efficiency improvements in the existing plants. In addition to conventional gas processing, a number of other CO2 removal applications are emerging which may provide considerable opportunity to the gas processors. These new applications include enhanced oil recovery (EOR) gas processing separation of CO2 from power plant flue gases to minimize green house gas emissions, and so forth. They require newer technology or modification of existing technologies. Formulated amines can play a significant role in these areas. A formulated amine can be broadly defined as an amine that has been specifically formulated to perform specific task, for example, selective separation of H2S from light hydrocarbons in the presence of CO2, bulk separation of CO2, and so on. A formulated amine can consist of a single solvent such as methyl di ethanolamine (MDEA) or a solvent mixture such as a mixture of MDEA and diethanolamine (DEA) in aqueous solutions. Most of the proprietary solvents marketed by the major solvent manufacturers are based on formulated amines. By judicious choice of a formulated amine or amine mixture, process efficiency of the existing plants can be enhanced significantly compared to the use of traditional amines. Furthermore, some of the gas processing problems that can not be dealt with using the conventional technology in an economical manner can be easily handled with formulated amines. EOR gas processing is such an example. In the case of EOR gas processing, the concentration and volume of CO2 to be separated from the produced gas increases with time. This creates a major challenge for the design engineer in the design of a processing plant flexible enough to handle variations in CO2 concentrations ranging from 0 to 80 %. Formulated amines may be an answer to this problem. This article will describe the challenges and the opportunities formulated amines may provide to the gas processing industry.

ISSN:0090-8312    

DOI:10.1080/00908319950014957

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

There are many heavy oil reservoirs with thin pay zones (less than 10 m). Conventional thermal recovery methods such as steam injection are not cost-effective for these thin reservoirs, due to excessive heat loss through the overburden. In order to minimize heat losses, it is necessary to be able to carry out controlled heating of the pay zone. One such way to introduce heat to the reservoir in a controlled manner is electromagnetic heating. This article describes laboratory studies on electromagnetic heating of a scaled model of a heavy oil reservoir with a thin pay zone. The combination of electromagnetic heating and gas injection with horizontal wells was studied. Higher electromagnetic frequencies provide faster heating rates and can over come problems associated with discontinuity of the media through which electro magnetic waves must propagate in the reservoir. Heat loss can also be minimized with the use of higher frequencies. For less viscous oils (less than 1000 mPs.s), it is not necessary to heat the entire pay zone. Heating of the wellbore vicinity is sufficient. Oil recoveries as high as 45 % of OIIP (Original Oil in Place) were achieved using electromagnetic heating and gas injection compared to estimated primary recovery rates of less than 5 %. The results obtained in this work clearly show that electromagnetic heating provides an effective means of recovering heavy oil from reservoirs with thin pay zones.

ISSN:0090-8312    

DOI:10.1080/00908319950014966

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

In this study, an interval parameter fuzzy relation analysis (IPFRA) model is proposed for environmental risk assessment of petroleum-contaminated aquifers due to leakage from underground storage tanks. The model can effectively incorporate effects of different pollutants and different remediation techniques within a general framework. Also, it can directly reflect uncertainties presented as inexact intervals for a number of modeling inputs. Results of a case study indicate that reasonable solutions for risk assessment under different system conditions have been generated. When no remediation action is undertaken, environmental conditions at the study site may be ''highly risky'' in terms of their relation to drinking water safety. Four potential site remediation strategies are analyzed. They have different environmental and economic characteristics, with lower risks generally correspond ing to higher costs. Trade-offs between environmental and economic objectives are then analyzed. In general, the IPFRA approach is useful for comprehensively evaluating risks within a system containing many factors with complicated interrela tionships. The modeling results have provided bases for determining desirable site remediation actions.

ISSN:0090-8312    

DOI:10.1080/00908319950014975

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Due to low oil prices, many of the conventional enhanced oil recovery (EOR) techniques have become unattractive. The biggest challenge for any novel recovery technique is to be able to produce under attractive economic conditions. Also, any novel EOR technique should be able to address marginal reservoirs, such as heavy oil reservoirs, reservoirs with bottom water, and others, because these reservoirs contain the most proven reserves. This article focuses on economically attractive EOR techniques. Many of these techniques are in the areas of heavy oil and tar sand reservoirs. Studies are presented for some of the most promising emerging technolo gies, such as electromagnetic oil recovery, cosurfactant enhanced chemical processes, microbial EOR, low pressure gas foam injection, and others. Also discussed is the use of horizontal wells in order to improve the effectiveness of various EOR schemes. Finally, some of the relevant scaling criteria and numerical simulation results are discussed in order to familiarize readers with the difficulties of scaling up laboratory results before planning a field application.

ISSN:0090-8312    

DOI:10.1080/00908319950014984

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor

摘要:

Historical methods of cleaning up petroleum hydrocarbons from the vadose zone, the capillary zone, and the aquifers are not technically true cleanup technologies but rather transfer techniques. In addition, environmental engineers are realizing that the standard remediation techniques are not entirely effective in removing the hazardous material in a reasonable time frame. Long-chain hydrocarbons such as kerosene, diesel, and waste oil are particularly difficult to remediate using conventional techniques. The use of bioremediation as an alternative remediation technology is fast becoming the technique of choice among many environmental professionals. This method offers substantial benefits not found in other remediation processes. Bioremediation is very cost effective, nondestructive, relatively uncomplicated in imple menting, requires nonspecialized equipment, and can be extremely effective in removing recalcitrant petroleum hydrocarbons. This study researched the availability of viable microbial populations in the arid climate in South Dakota. Exponential growth of the bacteria and the ability of bacteria to degrade long-chain hydrocarbons indicated that healthy populations do exist and could be used to mineralize organic hydrocarbons. Experimental results indicated that bioremediation can be effectively enhanced in landfills as well as in the subsurface using a supply of harmless nutrients. The biodegradation rate can be further enhanced with the use of edible surfactant that helped disperse the petroleum products. Also, the use of hydrogen peroxide enhanced the oxygen availability and increased the degradation rate. Interestingly, the bacterial growth rate was found to be high in difficult-to-biodegrade contaminants, such as waste oil. A numerical simulation program was also developed that describes the bacterial growth in the subsurface along with the reduction in substrate (contamination). Results from this program were found to be consistent with laboratory results. Finally, large-scale laboratory tests were performed. A comparison of these two sets of results revealed an interesting scaling correlation. Recommendations are made for proper scaling up of laboratory results.

ISSN:0090-8312    

DOI:10.1080/00908319950014993

出版商:Informa UK Ltd    

年代:1999

数据来源: Taylor