Browsing by Subject "petroleum"
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Item A Comparison of the Effects of Petroleum Substances on the Settlement of the Eastern Oyster, Crassostrea virginica(2012-10-19) Alsept, Karen SueIn Galveston Bay, Texas, the eastern oyster, Crassostrea virginica, is found throughout the bay both intertidal along mudflats and subtidal where their self-built reefs extend vertically deeper. The eastern oyster is an important ecological and economical resource and as such has led to studies regarding their community structure to permit effective creation of artificially built reefs and restoration of existing ones. The presence of the oil and gas industry coupled with increased oyster mortality led to investigations to determine the effects of petroleum substances on the setting, growth, and mortality of the eastern oyster. Many of those studies indicated increased settlement and increased growth of oysters on substrate coated with oil. A field conducted experiment was used to assess the settlement of oyster larvae on cleaned oyster shells coated with two different types of petroleum substances (mineral oil and motor oil), comparing viscosities, in a shallow bayou in Galveston, Texas, where the eastern oyster dominates the intertidal zone. Oyster shells were used as cultch material and divided into three groups; a non-treated control group, mineral oil treated group, and a motor oil treated group. Nekton assemblages, distributions of the ivory barnacle, Balanus eberneus, and Dermo disease infection were assessed. Settlement of oyster larvae occurred in all three groups with no significant difference of preference; algae and sediment present on the shells coupled with the presence of predators most likely caused reduced numbers of spat settlement. Species richness was equal among the groups but varied in evenness of individual species.Item A top-injection bottom-production cyclic steam stimulation method for enhanced heavy oil recovery(Texas A&M University, 2006-10-30) Matus, Eric RobertA novel method to enhance oil production during cyclic steam injection has been developed. In the Top-Injection and Bottom-Production (TINBOP) method, the well contains two strings separated by two packers (a dual and a single packer): the short string (SS) is completed in the top quarter of the reservoir, while the long string (LS) is completed in the bottom quarter of the reservoir. The method requires an initial warm-up stage where steam is injected into both strings for 21 days; then the LS is opened to production while the SS continues to inject steam for 14 days. After the initial warm-up, the following schedule is repeated: the LS is closed and steam is injected in the SS for 21 days; then steam injection is stopped and the LS is opened to production for 180 days. There is no soak period. Simulations to compare the performance of the TINBOP method against that of a conventional cyclic steam injector (perforated across the whole reservoir) have been made. Three reservoir types were simulated using 2-D radial, black oil models: Hamaca (9????API), San Ardo (12????API) and the SPE fourth comparative solution project (14????API). For the first two types, a 20x1x20 10-acre model was used that incorporated typical rock and fluid properties for these fields. Simulation results indicate oil recovery after 10 years was 5.7-27% OIIP with TINBOP, that is 57-93% higher than conventional cyclic steam injection (3.3-14% OIIP). Steam-oil ratios were also decreased with TINBOP (0.8-3.1%) compared to conventional (1.2-5.3%), resulting from the improved reservoir heating efficiency.Item Design of regulated velocity flow assurance device for petroleum industry(Texas A&M University, 2005-02-17) Yardi, Chaitanya NarendraThe petroleum industry faces problems in transportation of crude petroleum be- cause of the deposition of paraffins, hydrates and asphaltenes on the insides of the pipeline. These are conventionally removed using either chemical inhibitors or mechani- cal devices, called pigs, which travel through the pipeline and mechanically scrape away the deposits. These pigs are propelled by the pipeline product itself and hence travel at the same velocity as the product. Research has indicated that cleaning would be better if the pigs are traveling at a relatively constant velocity of around 70% of the product velocity. This research utilizes the concept of regulating the bypass flow velocity in order to maintain the pig velocity. The bypass flow is regulated by the control unit based on the feedback from the turbine flowmeter, which monitors the bypass flow. A motorized butterfly valve is used for actually controlling the bypass flow. In addition to cleaning, the proposed pig utilizes on-board electronics like accelerom- eter and pressure transducers to store the data gathered during the pig run. This data can then be analyzed and the condition of the pipeline predicted. Thus, this research addresses the problem of designing a pig to maintain a constant velocity in order to achieve better cleaning. It also helps gather elementary data that can be used to predict the internal conditions in the pipe.Item Optimization of a petroleum producing assets portfolio: development of an advanced computer model(2009-05-15) Aibassov, GizatullaPortfolios of contemporary integrated petroleum companies consist of a few dozen Exploration and Production (E&P) projects that are usually spread all over the world. Therefore, it is important not only to manage individual projects by themselves, but to also take into account different interactions between projects in order to manage whole portfolios. This study is the step-by-step representation of the method of optimizing portfolios of risky petroleum E&P projects, an illustrated method based on Markowitz?s Portfolio Theory. This method uses the covariance matrix between projects? expected return in order to optimize their portfolio. The developed computer model consists of four major modules. The first module generates petroleum price forecasts. In our implementation we used the price forecasting method based on Sequential Gaussian Simulation. The second module, Monte Carlo, simulates distribution of reserves and a set of expected production profiles. The third module calculates expected after tax net cash flows and estimates performance indicators for each realization, thus yielding distribution of return for each project. The fourth module estimates covariance between return distributions of individual projects and compiles them into portfolios. Using results of the fourth module, analysts can make their portfolio selection decisions. Thus, an advanced computer model for optimization of the portfolio of petroleum assets has been developed. The model is implemented in a MATLAB? computational environment and allows optimization of the portfolio using three different return measures (NPV, GRR, PI). The model has been successfully applied to the set of synthesized projects yielding reasonable solutions in all three return planes. Analysis of obtained solutions has shown that the given computer model is robust and flexible in terms of input data and output results. Its modular architecture allows further inclusion of complementary ?blocks? that may solve optimization problems utilizing different measures (than considered) of risk and return as well as different input data formats.Item Paleoenvrironmental Controls on Diagenesis of Organich-Rich Shales in the Eagle Ford Group(2014-08-27) Kruse, KendraCarbonate precipitation can be either promoted or inhibited by microbial processes in different redox zones. It is therefore possible for basin redox evolution to indirectly control early carbonate diagenesis and modify reservoir properties of corresponding shale units. The goals of this study were to analyze geochemical characteristics of the Late Cretaceous Eagle Ford Group in McMullen County, Texas to test the hypotheses that (1) the redox state of the water column controlled carbonate cement abundance and (2) carbonate cement lowered organic matter content by volumetric dilution. An x-ray analytical microscope was used to map elemental compositions of fresh core samples within the Eagle Ford Group. Resultant maps were used to characterize carbonate cements and to estimate the redox state of the overlying water column during deposition, as indicated by the relative abundances of the trace metals Mo, V, and Cr. Results indicate that cementation occurred early relative to compaction. Ti Kal normalized Mo Kal and CaKal fluorescence intensities are positively correlated throughout the unit, suggesting that carbonate cementation was related to the redox state. Total organic carbon is negatively correlated in the upper Lower Eagle Ford with (Ca Kal)/(Ti Kal) fluorescence ratio, consistent with volumetric dilution of organic matter by diagenetic cementation prior to compaction. In contrast, there is no significant correlation between total organic carbon and carbonate content in the more organic-rich Lower Eagle Ford.Item Radon (Rn-222) and thoron (Rn-220) emanation fractions from three separate formations of oil field pipe scale(Texas A&M University, 2004-11-15) Fruchtnicht, Erich HaroldOver the course of normal oil well operations, pipes used downhole in the oil and petroleum industry tend to accumulate a mineral deposit on their interior, which restricts the flow of oil. This deposit, termed scale, will eventually occlude the interior diameter of the pipe making removal from service and descaling a cost effective option. The pipes are sent to cleaning yards where they remain until descaling can be performed. This storage period can potentially create a health concern not only because of the external radiation exposure but also because of the radon gas emissions, both of which are due to the radioactive minerals contained in the scale. It was believed that the structure of the scale is formed tightly enough to prevent much of the radon from becoming airborne. The goal of this research was to determine the emanation fractions for the rattled scale samples from three formations. A high purity germanium detector was used to measure the activities of the parents and progeny of radon, and electret ion chambers were used to measure the concentration of radon emanated from the scale. The emanation fractions of between 4.9x10-5 and 1.08x10-3 for radon were a factor of approximately 100 smaller than previous research results. For thoron, the fractions were and 5.72x10-8 and 4.92x10-7 for thoron with no previous research to compare. However, information that pertains to the temperature dependence of emanation was included in this research and was not available for previous, similar research. Therefore, differences in the environment (e.g., temperature, humidity, etc.) in which the previous experiments were conducted, as well as differences in the scale formation types used, could account for the discrepancy. In addition, measuring the emanation fractions of the rattled scale was a method of determining whether surface to volume ratio dependence existed. After acquiring the emanation fractions, insufficient evidence of any surface to volume ratio dependence could be found.