CO2 EOR Potential in the Brent Group at the Statfjord Field

CO2 flooding is an enhanced oil recovery (EOR) technique that can be used to improve displace- ment efficiency and volumetric sweep efficiency. This is due to its favorable interactions with oil, which can be beneficial when trying to produce incremental oil. This method has been in- vestigated in this thesis. Statfjord is one of the largest oil discoveries in Europe, and has been producing oil since 1979. The main reserves are in the Brent group, and production from this reservoir is supposed to stop in 2025. A compositional model of the Brent group has been developed by Statoil, which is tuned to reflect the status in the reservoir in 2031. This model is used in this thesis to study the CO2 EOR potential for the Brent group, and see how much extra oil that can be produced by using CO2. Simulations on a field scale level have been performed, but also a pair of an injector and a producer has been studied for looking at injection strategies and compositional effects. The best scenario in this study can increase the oil recovery by 5.4% of the original oil in place (OOIP), by injecting 22 million tons of CO2 per year over a 25 year period. 3% of the OOIP can be produced by injecting 5 million tons of CO2 per year, for the same time period. Unless the CO2 can be brought to the oil field for 10 USD/bbl or less, the net present value (NVP) of the project is negative. For all the scenarios simulated, at least 72% of the CO2 injected will be stored in the reservoir. A reinjection of the produced gas seems to have a positive effect on the oil production, and if it is reinjected the storage percentage of CO2 can reach 100%. Continuous injection of CO2 has given the best results of the injection strategies studied in this thesis

Integration of Power-to-Gas in Gasendal and GoBiGas

Power-to-Gas, which is the term used to describe the use of electrolysis and Sabatier reactor systems to react H2 and CO2 and form CH4, is a technology that has received a great deal of attention recently. The produced CH4 can be used in a variety of applications, including fuel for vehicles and energy storage in existing natural gas networks. Research is currently being conducted on the performance of this technology, and several demonstration plants have been built. However, few evaluations have been made on the implementation of power-to-gas in existing biogas production plants. This thesis will look at the technical and economic aspects involved in integrating the power-to-gas technology in a biomass gasification plant (GoBiGas) and a biogas upgrading plant (Gasendal). The technical evaluation is carried out using the process engineering software Aspen Plus. The Sabatier reactor system is modelled and optimized with regard to material and reactant composition restrictions, and Pinch analysis is carried out to evaluate the potential for heat recovery. An economic evaluation is made to check the profitability of the implementation with respect to current energy market conditions, and a sensitivity analysis is done to conclude what future market changes and technology conditions may affect the economic outcome. In conclusion, the implementation of power-to-gas is profitable for neither of the two applications with current market and technology conditions. However, investment costs are predicted to fall and SNG prices are likely to rise in the future, which would benefit the economic outcome of the implementation

Echinoderms have bilateral tendencies

Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development. During embryonic development of starfish and sea urchins, the position and the developmental sequence of each arm are fixed, implying an auxological anterior/posterior axis. Starfish also possess the Hox gene cluster, which controls symmetrical development. Overall, echinoderms are thought to have a bilateral developmental mechanism and process. In this article, we focused on adult starfish behaviors to corroborate its bilateral tendency. We weighed their central disk and each arm to measure the position of the center of gravity. We then studied their turning-over behavior, crawling behavior and fleeing behavior statistically to obtain the center of frequency of each behavior. By joining the center of gravity and each center of frequency, we obtained three behavioral symmetric planes. These behavioral bilateral tendencies might be related to the A/P axis during the embryonic development of the starfish. It is very likely that the adult starfish is, to some extent, bilaterian because it displays some bilateral propensity and has a definite behavioral symmetric plane. The remainder of bilateral symmetry may have benefited echinoderms during their evolution from the Cambrian period to the present

Polarimetric Guided Nonlocal Means Covariance Matrix Estimation for Defoliation Mapping

In this study we investigate the potential for using synthetic aperture radar (SAR) data to provide high resolution defoliation and regrowth mapping of trees in the tundra-forest ecotone. Using aerial photographs, four areas with live forest and four areas with dead trees were identified. Quad-polarimetric SAR data from RADARSAT-2 was collected from the same area, and the complex multilook polarimetric covariance matrix was calculated using a novel extension of guided nonlocal means speckle filtering. The nonlocal approach allows us to preserve the high spatial resolution of single-look complex data, which is essential for accurate mapping of the sparsely scattered trees in the study area. Using a standard random forest classification algorithm, our filtering results in over $99.7 \%$ classification accuracy, higher than traditional speckle filtering methods, and on par with the classification accuracy based on optical data.Comment: Update to match final submitted version accepted to IGARSS 2020. 4 pages, 2 columns, 3 figure

Seismic Wave Attenuation in Carbonates

The effect of pore fluids on seismic wave attenuation in carbonate rocks is important for interpreting remote sensing observations of carbonate reservoirs undergoing enhanced oil recovery. Here we measure the elastic moduli and attenuation in the laboratory for five carbonate samples with 20% to 30% porosity and permeability between 0.03 and 58.1 mdarcy. Contrary to most observations in sandstones, bulk compressibility losses dominate over shear wave losses for dry samples and samples fully saturated with either liquid butane or brine. This observation holds for four out of five samples at seismic (10–1000 Hz) and ultrasonic frequencies (0.8 MHz) and reservoir pressures. Attenuation modeled from the modulus data using Cole-Cole relations agrees in that the bulk losses are greater than the shear losses. On average, attenuation increases by 250% when brine substitutes a light hydrocarbon in these carbonate rocks. For some of our samples, attenuation is frequency-dependent, but in the typical exploration frequency range (10–100 Hz), attenuation is practically constant for the measured samples

Diagnostics of seismic time-lapse effects of sandstones based on laboratory data

We evaluated a viscoelastic modeling of P- and S-wave velocity dispersion, attenuation, pressure, and fluid effects for a set of siliciclastic rock samples. Our analysis used a published laboratory data set of 63 sandstones with a wide range of compositional heterogeneities. We observed a notable correlation between the (velocity and attenuation) pressure sensitivity and the abundance/lack of quartz in the samples. We included compliant pores (low-aspect ratio) proportionally to the content of secondary minerals to account for the differential sensitivity to pressure. The observed velocity and attenuation were well reproduced by the applied viscoelastic modeling. We found that pores of significantly different scale required pore fluid relaxation time constants of proportionally different magnitudes to reproduce the velocity and attenuation measurements. The relaxation time constant of crack-sized pores can be one order of magnitude smaller than the constant of mesopores. Moreover, the velocity dispersion and attenuation signatures revealed that a pore textural model dependent on lithological composition is critical in the prediction of time-lapse fluid and pressure responses.publishedVersio

The biology of a sewage treatment plant: A preliminary survey, Decatur, Illinois

Reprint. Originally published: Sewage works journal ; v. 1, no. 4 (July, 1929).Includes bibliographical references

Method to identify opportunities for CCU at regional level — Matching sources and receivers

Carbon Capture and Utilization is an attractive strategy not only due to its potential for CO2 emissions reduction but also because it enables the creation of valuable products. The development of CO2-based industrial symbiosis partnerships can contribute significantly towards achieving the goals of GHG emissions reduction on a European level by 2030, while at the same time it leads to an increased added value through the development of new production lines and carbon neutral products. The presented article focuses on identifying potential partnerships between companies that produce CO2 and companies that may reuse CO2 as input for their industrial process. A novel methodological framework is presented based on developing generic matrices for CO2 sources and receivers and matching the industrial units based on geographical and technical criteria. Moreover, the paper provides the technical requirements of 17 CO2 utilization technologies with relatively high technology readiness level, including the CO2-to-product ratio, the required purity, pressure, temperature and the presence of a catalyst, as well as potential synergies and additional requirements. The methodology has been applied to the Västra Götaland region in West Sweden and the most promising CCU symbiosis have been identified. These include mineral carbonation (annual uptake: 59,600 tCO2), greenhouses (26,000 tCO2), algae production, methanol production (85,500 tCO2), power to gas (66,500 tCO2), pH control, lignin production, polymers synthesis and concrete curing (96,000 tCO2). If all of them could be applied, the total annual CO2 reduction would exceed 250,000 tCO2 per year