Carbon dioxide (CO2) sequestration in saline aquifers has been proposed as one of the most practical options for reducing CO2 emissions into the atmosphere. Massive CO2 injection into an aquifer would alter the geochemical equilibrium between the rock-forming minerals and the formation water. In this work, a novel and simple predictive tool is presented to estimate the formation of calcium carbonate (CaCO3) scaling as a function of pH, temperature, ionic strength of the solution, calcium cation concentration, bicarbonate anion concentration, and CO2 mole fraction when the water mixture is saturated with a gas containing CO2 to evaluate the effect of solution conditions on the tendency and extent of precipitation. The proposed simple method covers concentrations of calcium cation or bicarbonate anion in the range of 10 to 10 000 mg/L, with temperature ranging between 5 and 90°C, total ionic strength ranging between 0.1 and 3.6, and pH values ranging between 5.5 and 8. The predicted values are found to be in good agreement with the reported data, with average absolute deviations being less than 2.6%. The proposed tool is superior because of its accuracy and clear numerical background based on the Vandermonde matrix, wherein the relevant coefficients can be retuned quickly if more data become available in the future. The simple predictive tool proposed in the paper can be of immense practical value for engineers and researchers to have a quick check on the formation of calcium carbonate scaling when the water mixture is saturated with a gas containing CO2 at various conditions without opting for any experimental measurements. In particular, process engineers would find the proposed method to be user friendly, involving no complex expressions and presenting transparent calculations.
Libre, Jean-Marie (Total E&P) | Tripathi, Amita (Fluidyn-Transoft) | Le Guellec, Malo (Fluidyn-Transoft) | Mailliard, Thibault (Fluidyn-Transoft) | Guérin, Stéphanie (Total E&P) | Souprayen, Claude (Fluidyn-Transoft) | Castellari, Aldo (Total E&P)
The knowledge in real time of the concentration fields resulting from the accidental release of a hazardous substance would be extremely valuable information as support for emergency actions and for impact evaluation on the industrial site itself and its vicinity. For that purpose, a modeling platform is being developed and applied to simulate in real time the atmospheric dispersion of a hazardous substance at the scale of the industrial site and also of its surroundings. The industrial site of Lacq (France) has been chosen as a pilot, and the key hazardous substance considered in this study is hydrogen sulfide (H2S). A 3D computational-fluid-dynamic (CFD) model (Fluidyn-Panepr) has been chosen to simulate the 3D wind-field pattern on the industrial site, taking into account the details of the installations. This approach enables a simulation as close as possible of the turbulence and flow around the buildings that could not be achieved with a standard Gaussian approach. For that purpose, a detailed numerical model of the Lacq installation was built on the basis of a thorough review of the existing installations and an evaluation of their size and "porosity." Wind fields were calculated for a set of predefined boundary conditions based on the climatology of the site. Investigations were carried out to ensure that site information systems could deliver the information available from the H2S sensors and on-site meteorological station in real time. The real-time approach is made possible by the use of a complete wind-field precalculated database automatically selected in case of accidental release by comparison with real-time wind-direction and -speed measurements from the meteorological station located on the industrial site. The location and intensity of the source term are determined using a probabilistic approach (Bayesian inference), making use of both real-time measurements and precalculated concentration responses from unitary emissions (puffs) on sensors. This approach was validated successfully using a limited number of sensors and sources but with the complex structure and flow patterns expected on the site. The activation of the simulation platform is triggered by the detection of threshold concentrations at the sensors. The estimated source term is then used in forward dispersion mode to simulate the dispersion in (fast) Lagrangian puff mode. The modeling platform will be validated through measurement campaigns with a neutral species in 2010.
Carbon emitted on account of our continued use of fossil fuel can be offset using carbon capture and storage (CCS). The technology for this exists, but the economics of it is context dependent, and CCS has shown itself to be not very cost effective in oil sands. Committing to the large-scale sequestration projects needed without properly considering alternatives can prove costly at both the economic and social levels. Charcoal sequestration, discussed earlier by Gupta, provides a few advantages, such as being less costly and lacking any post-operation liabilities. Above all, it is reversible, allowing flexibility of policy and operation and avoiding long-term or large-scale commitments.
The economics of the charcoal approach mainly depends on two factors--the cost of the feed biomass and the cost of processing. The first of these is addressed by using municipal waste as feedstock, which can be available free of charge. Expectedly, the cost of processing, the second factor, depends on the apparatus and the scale of operation.
In this paper, the authors discuss the benefits and drawbacks of prominent traditional and modern apparatus used for conversion of biomass to charcoal and describe a simple and pragmatic apparatus that could be assembled relatively easily for a small-scale operation such as processing industrial-camp-generated solid organic waste.
Offsetting carbon in this manner obviously can be a good way to initiate demonstration projects for the charcoal-sequestration approach because it also helps with waste management. These demonstration projects in turn will help evaluate various aspects of this novel method of sequestration and enhance public awareness on the subject, which in turn will help society make an informed choice to embark on a correct course of action for atmospheric carbon abatement. Additionally, in light of the growing per capita waste worldwide, use of municipal waste as feedstock for charcoal sequestration can be a significant measure of carbon offset at global scale in its own right.
While remote parts of the world are awash with hundreds of trillions of cubic feet (Tcf) of natural gas, the industrialized West and emerging economies of the East cannot get enough of the clean-burning, environmentally friendly fuel. The problem is transporting this compressible fluid long distances and across major bodies of water. For markets more than 1,500 miles distant, liquefied natural gas (LNG) has proved to be the most economic option. By refrigerating natural gas (primarily methane) to 260°F (162°C), thereby shrinking its volume by 600:1, natural gas in the form of LNG can be transported in large insulated cryogenic tankers at reasonable cost.
Natural-gas liquefaction is a series of refrigeration systems similar to home air-conditioning (AC) systems, consisting of a compressor, condenser, and evaporator to chill and condense the gas. The difference is in the scale and magnitude of the refrigeration. A typical single-train LNG plant may cost USD 1.5 billion and consume 6 to 8% of the inlet gas as fuel. Because many of the impurities (e.g., water vapor, carbon dioxide, hydrogen sulfide) and heavier hydrocarbon compounds in natural gas would freeze at LNG temperatures, they must first be removed and disposed of or marketed as separate products.
This paper will provide an overview of LNG liquefaction facilities, from inlet gas receiving to LNG storage and loading. However, the focus is on the liquefaction process and equipment. Differences among the commercially available liquefaction processes (e.g., cascade, single mixed refrigerant, propane precooled mixed refrigerant, double-mixed refrigerant, nitrogen) will be discussed. The aim is to provide SPE members with a clear understanding of the technologies, equipment, and process choices required for a successful LNG project.
Ultrasonic gas-leak detection (UGLD) is gaining broader acceptance in the oil and gas industry as a means for detecting combustible-gas leaks. UGLD responds to high-pressure leaks by measuring the airborne ultrasound emitted, which when detected by the sensor provides a measure that is proportional to the leak rate. Principal advantages of the technology are that it does not require gas to be transported to the detector and it provides coverage for a relatively large area, up to 20 m in radius, suggesting that UGLD is suitable for detecting gas releases in open, well-ventilated sections of offshore platforms.
Despite such advantages, the location criteria and commissioning and routine-maintenance procedures for UGLD are not as well understood as those for conventional gas detectors. A reason might be that UGLD requires the establishment of an ambient ultrasonic background-noise level to decide the alarm level and assist with selection of optimal location, a requirement that has no parallel with point IR or catalytic sensors. Location of ultrasonic gas-leak detectors is also based on identifying the potential sources of leaks and taking into account acoustic reflections and interferences caused by continuous or short-time-scale background ultrasonic noise.
Such newness might be enough to give some would-be users pause. They may believe that UGLD is for people with high technical competence or that mapping, commissioning, and maintenance are best left to UGLD-equipment manufacturers. Experience by one of the authors of this monograph suggests the contrary. UGLD, for its reliance on ultrasound as a proxy for a gas leak, is a simple concept to understand. Over the course of more than 3,000 installations during the last 10 years, offshore-platform personnel have developed best practices that reduce the time and cost required for installing and commissioning ultrasonic gas monitors and that ease the burden on maintenance. In this report, we examine several of these procedures and highlight the simplicity of installation and maintenance of this method of gas detection.
Acrolein (2-propenal) is a highly effective microbiocide and sulfide scavenger that has been commercially available since 1960 and has been used widely in the oil- and gas-production industry. Acrolein is a liquid product supplied in and applied from specialized containers, eliminating potential releases from transfers between tanks. The acrolein containers are built to comply with international transportation regulations. This paper will cover the development of a safety-management program and standardization of application equipment that allow the usage of acrolein for applications with a risk comparable to, or in some cases lower than, that for conventional chemical products.
Standardized operating procedures, closed-system application equipment [verified by industrial hygiene (IH) monitoring], and redundant safety devices are built into the system to prevent chemical exposures or misapplications. Applications are performed by trained and certified personnel who have completed a specific competency evaluation under field conditions. A detailed and customized safety-management program is completed and implemented for each application with extensive client participation.
This paper will cover the core of the safety-management program, which focuses on developing site-specific elements, including process safety information, process hazard analysis, operating procedures, employee and contractor training, applicator competency and field evaluation, prestartup safety reviews, management of change, and emergency planning and response procedures.
A safety audit program is also implemented to ensure that the completed safety management program complies with each element. Audits are conducted at the actual location during the course of the chemical application. A strong safety-management program and standardized application system have been shown to reduce personnel and environmental risks by lowering the potential for misapplications or equipment failures. These systems have allowed successful treatment programs on numerous global production assets. To validate this, a series of case histories will be presented that highlight the best practices that enable the safe application of acrolein.
Popli, Sahil (The Petroleum Institute) | Rodgers, Peter (The Petroleum Institute) | Eveloy, Valerie (The Petroleum Institute) | Al Hashimi, Saleh (The Petroleum Institute) | Radermacher, Reinhard (University of Maryland) | Hwang, Yunho (University of Maryland)
The oil and gas industry is under increasing pressure to improve the efficiency of its energy-intensive oil- and gas-processing operations through improved energy use and waste-heat recovery. This paper explores the use of waste-heat-powered absorption cooling to boost the efficiency of natural-gas (NG) processing, enhance hydrocarbon recovery, and reduce utility cost in an NG plant. A thermodynamic analysis of a gas turbine waste-heat-powered double-effect water/lithium bromide (H2O/LiBr) absorption chiller in an integrated NG plant is presented.It is found that waste heat recovered from turbine exhaust gases could be used to provide enhanced process cooling capacity to the NG plant through absorption cooling. The results suggest that adouble-effect LiBr absorption chiller utilizing 34.6 MW of gas-turbine exhaust heat could provide 45 MW of cooling at 5°C.This could save approximately 9 MW of electric energy required by a typical compression chiller, while providing an equivalent amount of cooling.The associated annual savings are estimated to be approximately USD 7.8 million/yr, with a payback period of 2 years.
The application and adoption of collaboration centers in the exploration and production (E&P) industry have increased significantly in the past decade. The benefits of collaboration-center use have been clearly identified including the delivery of cost-effective and fully integrated multidiscipline field, reservoir, and well management decisions.
Saudi Aramco has established a number of collaboration centers that directly capitalize on large-scale, multidiscipline, value-added technical and business collaborations. These centers, for instance, cover areas of exploration, geosteering, real-time drilling, field development, and production and intelligent-field management. Tangible economic and technical benefits of such collaboration encompass improved recovery, improved technical workflows, technology innovation, enhanced staff-skill-set development, and significant reduction of critical field-development-study cycle times. This paper outlines Saudi Aramco's experience from 5 years of using multidiscipline collaboration workrooms with a focus on facility design, technology (software and hardware) support, and lessons learned.
Advances in interactive, high-performance technology solutions (hardware and software) and easy-to-use visual communication technologies present additional opportunities to extend and enhance the value-added impact of collaboration centers, including virtual collaboration. The need for physical, localized centers will be discussed, compared, and evaluated in the context of virtual-collaboration-center potential. The paper presents a "checklist" methodology for collaboration-center design, layout, support, and maintenance incorporating the challenges of continuous technology advancement and multidiscipline project complexity.
During the concept comparison and selection phase of capital projects, decision makers compare development options and select one option to carry forward to detailed engineering. This effort is often complicated by uncertainty in one or more of the critical inputs. Therefore, project teams typically investigate how different assumptions about the uncertainty influence optimal decisions. In cases where initial investment decisions are costly to change, the analysis of facility flexibility increases in importance. The goal is to find the optimal balance between initial capacity and the allocation of space and other resources for future expansion. This paper reports the results of a research project in which the authors develop an integrated asset model for a hypothetical deepwater asset and use the model to investigate various aspects of facility design under uncertainty. The method produces estimates for the optimal initial capacity, the likelihood of expansion, the expected size of expansion, and the willingness to pay for the option to expand. The approach is systematic; the model solves quickly and, thus, enables a wide scope of uncertainty analysis. The graphical output is intuitive and facilitates communication between the facility engineer, subsurface engineers, and management.
One of the most striking demonstrations of intermolecular forces is the tension at the surface of liquid n-alkanes. The prediction of surface tension is important in the design of distillation towers, extraction units, and tower internals such as bubble caps and trays because it has a considerable influence on the transfer of mass and energy across interfaces. Surface-tension data are needed wherever foaming emulsification, droplet formation, or wetting are involved. They are also required in a number of equations for two-phase-flow calculations and for determining the flow regime. Petroleum engineers are especially interested in the surface tension in the extraction of crude oil where adding surfactants to modify the interfacial properties between crude oil and the geological reservoir can improve production and increase oil yields. In this work, a simple predictive tool using Arrhenius-type asymptotic exponential function, the Vandermonde matrix, and Matlab (Matlab 2008) technical computing language is developed for the estimation of surface tension of paraffin hydrocarbons as a function of molecular weight and temperature. The surface tension is calculated for temperatures in the range of 250 to 440 K and paraffin hydrocarbon molecular weights between 30 and 250. The proposed numerical technique is superior owing to its accuracy and clear numerical background, wherein the relevant coefficients can be retuned quickly if more data become available in the future. Estimations are found to be in excellent agreement with the reliable data in the literature, with average absolute deviation being less than 2%.