<p> Hydraulic Fracturing is a cost-effective technique that has been widely integrated and applied to commercial production of oil and gas from unconventional reservoirs. Advancement of this technique brings more complexity into it, making optimization process more complicated in terms of economic analysis and decision making. Selection of proppant for treatment is a crucial and essential decision that has a significant impact on fracturing stimulation and well economics. This analysis indicates advantages and disadvantages of different types of proppant and provides a comparison of proppant performances considering proppant type, mesh size and concentration in order to identify the best scenario of proppant application in terms of economical profitability. </p><p>

<p> Abstract In this work, we studied the Eagle Ford Shale and experimented in detail to create a baseline to address the relative permeability of specific ions in shale. The study identifies that: (1) Ions are dispersed in a specific sequence (Na⁺, Ca²⁺, Mg²⁺). (2) As ions are dispersed, this allows the gas bubbles out of the shale/soil and forces the flakes and fragments to float to the top of the water on the vessel. The floating particles, depending on the type of cations released from the shale mass move towards a specific ion electrode. (3) Detachment or bursting of gas bubbles may initiate a shift or break in the shale/soil formation. (4) Calcium electrical potential, Eh, goes from negative to positive. This indicates an unstable potential with respect to time around the length of the well bore. (5) The release of ions depends on the diffusion properties of water penetrating the shale/soil mass. The motion of the shale/soil floating material is a vortex-like motion. </p><p> We conclude that by using SAR, it will help predict where the wellbore is stable or unstable based on the curve where certain drops or peaks or located. By creating a baseline measure using deionized water it is possible to predict the relative permeability of wellbore drilling of the Eagle Ford Shale using SAR. </p><p> Taking note of the ionic relative permeability as observed in our experiments, we decided to use the SAR method for estimating the relative permeability of shale/soil to various ions. All of this is based on where the most ionic flow occurs under given wellbore conditions. This understanding is further applicable to the design of certain type of frac fluids or design of a compatible drilling fluid for drilling a specific shale/soil.</p><p>

<p> The lack of cutting transportation during drilling operations can lead to large amounts of non productive time and costly solutions to address the issue. The objective of this study was to investigate the cutting velocity through an experimental approach. Dimensionless groups were formed based on the independent variables that affected cutting velocity. The experimental approach was analyzed through film software, which allowed for the cutting velocities to be calculated. Regression models of cutting velocity with respect to each dimensionless group were formed and validated through a statistical analysis. Only the second dimensionless group (?2) representing the volume of cuttings injected into the drillpipe with respect to the cubed value of the outer diameter of the drillpipe was proven to be insignificant. </p><p> Once the remaining regression models were validated, multiple linear regression analyses were conducted to relate each dimensionless parameter to the cutting velocity. This introduced a new empirical model to represent the cutting velocity based on the five significant dimensionless groups outlined in this study. The multiple linear regression model yielded an R-squared value of .81, which suggests a strong correlation for the data. This model was also validated through statistics. Each parameter except for the intercept of the model was confirmed to be significant. Other parameters that were excluded from the model due to the lack of equipment precision could be examined. A sensitivity analysis was conducted to highlight how each dimensionless group directly affected the cutting velocity. New correlations and trends may be estimated with more data from additional experiments outside the range of this study. Overall, this will allow the foundation of the model to be further improved.</p><p>

<p> Superhydrophobic coating reduces the fluid/solid interaction leading to ultra-hydrophobicity or the Lotus effect. The objective of this study is to determine how this phenomenon can be applied in petroleum production systems to enhance fluid flow in propped fractures using superhydrophobic coating on the surface of proppants. Permeability and wettability of coated sandstone samples are compared with the non-coated ones to create a base case for the study. Later sand packs are tested to determine the magnitude of enhancement in fracture conductivity after the modification is applied on sand proppants. The samples are measured for their absolute permeability and relative permeabilities to test the changes in flow for both the single-phase and two-phase fluid flow. The test results show a considerable increase of up to 98% for the single-phase flow and a 23% for the two-phase flow for the sand pack samples. The wettability test confirms that the coating modifies the samples from its initial water-wet state to a partial-wet state. Since the production rate of tight and shale reservoirs is low especially in liquid-rich reservoirs, a significant amount of water is injected for reservoir stimulation; enhancement in fracture conductivity as a result of proppant surface modification can have a meaningful impact on the recovery of these reservoirs. This study uses experimental techniques to show the effectiveness of superhydrophobic coating on the reduction of friction which can lead to enhancement in fracture conductivity. </p><p>

Thesis (M.B.A.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-01

The discourse on stability of petroleum contracts revolves around how to resolve the tension between the sovereign right to regulate the petroleum industry and the necessity to protect the legitimate interests of foreign investors. The irreversible nature of investment in the petroleum sector, the long pay back period in petroleum contracts, and the political and commercial risks inherent in petroleum projects necessitates stability over the life of the contract as an essential condition for achieving economic interests for the main players in the petroleum industry. The stability of a petroleum contract involves a complex interaction of the legal, economic and political environment in the host country in which it operates and is profoundly shaped by the interplay between internal and external factors governing the petroleum industry. The aim of the thesis is to examine and analyse the recent trends on stability of the petroleum contract in developing countries and economies in transition. Perception of petroleum as a finite, non-renewable resource and the attendant public interest dimension embedded in the contractual arrangements for its exploitation makes the petroleum industry a highly regulated and historically popular area of state intervention. Petroleum contracts are also vulnerable to various kinds of change of circumstances, which can disturb the economic equilibrium of contracts. Stability mechanisms in legal, contractual and economic forms are needed to counter these political, fiscal and commercial risks in petroleum contracts.The study observes that over the last two decades, the fierce competition among the developing countries and economies in transition for attracting foreign investment in natural resources exploration and the end of their radical nationalistic feelings and hostile attitude towards foreign investment have persuaded them to provide favourable conditions in petroleum contracts for the petroleum companies. The study finds that the petroleum contracts in these countries during this period have been marked by increased stability guarantees, greater flexibility in fiscal terms and increased efforts of the parties to make provisions for renegotiation and adaptation of the contract in changing circumstances to maintain stability in the contract and to attract foreign investment in petroleum projects. The growing concerns about negative environmental impact and consequently regulatory and liability risks by the host states have appeared as a significant political risk factor to the petroleum companies. Similarly, host communities' hostile actions spurred by negative social impact of petroleum operations and human rights violations at various stages of petroleum development can pose a threat to stability and to the economic viability of petroleum projects. The study emphasises that integration of environmental and social concerns in petroleum development, assessment of environmental and social impacts, consultation with key stakeholders in the project design and implementation, equitable distribution of economic benefits from the project, respect for human rights of the host community in petroleum exploitation are all seen as key issues to be addressed in order to reduce negative impacts from project, and to enhance stability of the projects. A clearly defined role for the government and company in the area of social responsibility is needed to reduce much of the uncertainty about the allocation of responsibilities that they should undertake.

Polyamide-11 (PA11) is a polymer of the Nylon family whose monomer is obtained from the castor bean, a renewable resource. It is widely used in offshore oil and gas production as a non-rigid flexible pipe liner, allowing for oil and gas transport from the wellhead to floating platforms for processing. The degradation of PA11 over time may lead to the pipe's failure, with possibly catastrophic results which include loss of life. Until now, the characterization of the degredative process has been limited to laboratory studies of the effects of water and temperature on the rate and degree of hydrolysis. In this dissertation, a more exact model than those proposed in the literature thus far is defined and used to quantify the effects of temperature on the rate and degree of PA11 hydrolysis. This is performed using accelerated aging experiments in the lab which are evaluated by a primary means of molecular weight determination, size exclusion chromatography---multiple angle laser light scattering (SEC-MALLS). The effects of methanol and ethanol, used in the industry to control solid hydrate formation, are then characterized with respect to concentration and temperature, a topic which has not yet been addressed in the literature. Also novel to this work is the discovery of the effects of acetic acid, valeric acid, and 3-cyclopropionic acid on the rate and degree of PA11 hydrolysis. While these acids are present in the offshore oil and gas environment, acetic acid is the most common, and has been identified as a serious factor affecting degradation. The effects of acetic acid on rate and degree of hydrolysis are incorporated into the temperature dependence described above, and adapted to a model well suited for characterizing the degradation of PA11 in the changing temperature environments found in the field. By characterizing coupons removed from PA11 pipes in oil production fields in various parts of the world, the model is tested and used to predict aging of PA11 pipe. The model is shown to be effective at predicting degredation for times greater than ten years, which has never before been described. The effects of annealing coupled with decline in molecular weight on PA11 mechanical properties in accelerated aging experiments versus aging in the field environment is discussed. These contributions to understand and predict the aging of PA11 flexible pipes are central to increasing the safety of offshore oil and gas production, a topic that today is vastly important.

Key petrophysical properties of reservoir sequences are determined by their individual mineral compositions, and are routinely evaluated through the analysis of cores and geophysical well logs. However, mineralogical studies are seldom incorporated in reservoir assessment. The objectives of the study were to investigate the influence of mineralogy on petrophysical properties of petroleum reservoir beds and the application of mineralogical studies in reservoir evaluation. Mineralogical analyses were performed on core samples from the Plover Formation, the principal reservoir sequence in the Northwest Shelf area of Australia, intersected in two separate wells in the Laminaria petroleum field. The techniques used included X-ray powder and oriented-aggregate analysis, optical microscopy and whole rock geochemistry. Quantification of each mineral phase based on whole-rock powder data was performed using the Rietveld-based Siroquant technique. Results from the Siroquant assay were used as an indicator of mineralogy for the individual samples and were compared with core plug and geophysical log data. X-ray micro-tomography analysis of selected samples was also performed. The reservoir sequences in both wells were sand-dominated, consisted mostly of quartz, clay mineral matrix and cement of silica, pyrite or calcite. The abundance of clay minerals increased in the shale and shaly sandstone intervals. Comparison of mineralogical and core plug analyses of samples from the same depths showed that the down-hole variations in porosity, permeability, grain density and radioactivity were accompanied by changes in mineralogy. Higher proportion of clay minerals in shales was indicated by higher gamma log signals. The gamma log may be taken as an indicator of shaliness only in intervals where kaolinite is proportional to the quantity of illitic clays. Sonic log and neutron log porosity values are comparable with core plug porosity data in sandstone intervals. However, clay minerals increase the sonic log response, thereby increasing porosity in shaly intervals. Clay minerals tend to decrease the neutron log response causing higher porosity indication in shales, similar to that expected in sandstones. Routine density log analysis underestimated porosity values because of the contribution of dense minerals to the bulk density of the formation. Use of laboratory determined grain and fluid densities resulted in improved density log porosity compared to core porosity. X-ray tomography analysis revealed an overall positive correlation between mineralogy and porosity data. Routine geophysical log evaluation revealed inconsistent results when compared to core analysis data because of the influence of minerals on various logs. It is essential that mineralogical studies be included in reservoir assessment. X-ray tomography may provide an alternative approach in evaluating porosity and mineralogy.

The international oil and gas industry views China as a key country in its search for petroleum exploration and development investment opportunities. China offers a range of opportunities ?? from mature, producing areas to frontier exploration areas. When Oil and gas companies make investment decisions to explore for and develop petroleum resources in a particular country, they need to examine many aspects of that country. The decision to invest focuses on assessments of the likely economic rewards and the risks involved. In this thesis, I attempt to provide a detailed assessment of various factors affecting the economics of petroleum exploration and development in China from an oil and gas investors?? point of view. The thesis is aimed at assisting international oil and gas companies to make investment decisions and assisting their understanding of the petroleum prospects in China. Based on detailed economic modelling, the thesis aims to demonstrate the profitability of exploration and development of a range of hypothetical but representative oil and gas prospects and discoveries in different areas in onshore and offshore China. The thesis also reviews the key fiscal terms in China and shows the economic impact of individual components of Chinese fiscal terms on field developments in China. The thesis quantifies and analyses the impact of Chinese fiscal terms by measuring the Government Take for a range of hypothetical oil field developments. It includes an analysis of the flexibility of the Chinese fiscal terms by quantifying the effect of Government Take on marginal field developments. In addition, the thesis intends to assess the competitiveness of Chinese fiscal regime in terms of its severity and flexibility as compared to other fiscal regimes in the Asia Pacific Region.

<p>This Master Thesis work aims to find a model system combining the positive effects of surfactant and polymer flooding to enhance oil recovery. This report presents the results of 12 core floors performed to enhance recovery of waterflood residual oil. The recovery is enhanced by a visous surfactant flood consistent of one polymer to increase the viscosity, one surfactant for interfacial tension reduction, and one di-alcohol to function as co-surfactant and for salinity control.</p><p>The chemical treatment that gave the best result, gave an additional oil production normalized on OOIP of 20%, improving the oil recovery from 45 to 66% mostly by the means of mobility control. Pure viscosity floods gave an additional recovery of 12 to 13% of OOIP.</p><p>Novel technology is used to investigate environmental friendly enhanced oil recovery. A biopolymer made out of microfibrils from wooden material was for the first time ever to my knowledge, attempted used in a core flood to enhance oil recovery.</p><p>A viscous surfactant tertiary recovery process may help improve oil recoveries from many marginal oil fields or those that face shut-down due to uneconomic operating costs, but still contain significant amounts of oil. </p>