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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Using simple models to describe oil production from unconventional reservoirs

Song, Dong Hee 17 July 2014 (has links)
Shale oil (tight oil) is oil trapped in low permeability shale or sandstone. Shale oil is a resource with great potential as it is heavily supplementing oil production in the United States (U.S. Energy Information Administration, 2013). The shale rock must be stimulated using hydraulic fracturing before the production of shale oil. When the hydrocarbons are produced from fractured systems, the resulting flow is influenced by the fracture, the stimulated rock, and the matrix rock. The production decline rates from shale oil reservoirs experience flow regimes starting with fracture linear flow (fracture dominated), then bilinear flow (fracture and stimulated rock dominated), then formation linear flow (stimulated rock dominated), and finally pseudo-radial flow (unstimulated matrix rock dominated) (Cinco-Ley 1982). In this thesis, daily production rates from a shale oil reservoir are modeled using a simple spreadsheet-based, finite difference serial flow simulator that models the single-phase flow of a slightly-compressible oil. This simulator is equivalent to flow through multiple tanks (subsequent part of the thesis will call these cells) through which flow passes serially through one tank into the other. The simulator consists of 11 tanks. The user must specify the compressibility-pore volume product of each tank and the transmissibility that governs flow from one tank to another. The calculated rate was fitted to the given data using the Solver function in Excel. The fitted matches were excellent. Although we can adjust all 22 parameters (2 per cell) to affect the simulation results, we found that adjusting only the first three cells nearest to the well was sufficient. In many cases, only two cells were enough. Adjusting 4 or more cells resulted in non-unique matches. Furthermore, the properties of the very first cells proved insensitive to the matches when using the 3 cells to match the data. The cells in the 2 cell model represent the stimulated zone and the unstimulated rock. Likewise, the cells in the 3 cell model represent the hydraulic fracture, the stimulated zone, and the unstimulated rock. The accessed pore volume and transmissibility were responsive to the injected sand mass and fluid volume up to approximately 10⁶ kg and 7000 m³ respectively; injecting more sand and fluids than this caused negligible increases in the accessed pore volume and transmissibility. This observation suggests that the sand does not migrate far into the fractures. Similarly, it was observed that the number of stages was positively correlated with cell transmissibility and pore volume up to 20 stages. These results suggest that fracture treatments were significantly over designed and injecting less sand and water in fewer stages would optimize the economics of similar projects. To our knowledge this is the first work to analyze the results of fracture treatments by matching with pore volumes and transmissibility in a simple serial cell flow. / text
2

World oil supply and unconventional resources : Bottom-up perspectives on tight oil production

Wachtmeister, Henrik January 2018 (has links)
Oil is the world’s largest primary energy source. It dominates the transportation sector which underpins the world economy. Yet, oil is a nonrenewable resource, destined not to last forever. In the mid-2000s global conventional oil production stagnated, leading to rising oil prices and fears of permanent oil scarcity. These fears, together with the high prices, receded with the unforeseen emergence of a new supply source: tight oil. This licentiate thesis investigates unconventional tight oil production and its impacts on world oil supply in terms of resource availability and oil market dynamics, and in turn briefly discusses some possible wider economic, political and environmental implications of these impacts. The thesis is based on three papers. The first investigates the usefulness of bottom-up modelling by a retrospective study of past oil projections. The second looks at how unconventional tight oil production can be modelled on the well level using decline curve analysis. The third derives typical production parameters for conventional offshore oil fields, a growing segment of conventional production and a useful comparison to tight oil. The results show that tight oil production has increased resource availability significantly, as well as introduced a fast responding marginal supply source operating on market principles rather than political ones. The emergence of tight oil production has altered OPEC’s strategic options and led to a period of lower and less volatile oil prices. However, this condition of world oil supply can only last as long as the unconventional resource base allows, and, at the same time, total fossil fuel consumption will have to fall to limit climate change. It is concluded that this breathing space with lower oil prices could be used as an opportunity to develop and implement policy for an efficient managed decline of global oil use in order to achieve the dual goals of increased human economic welfare and limited climate change, and in the process preempt any future oil supply shortage. Unconventional tight oil production can both help and hinder in this endeavor. Accurate models and analyses of oil production dynamics and impacts are therefore crucial when maneuvering towards this preferred future.
3

Kurz- und langfristige Angebotskurven für Rohöl und die Konsequenzen für den Markt

Schlothmann, Daniel 20 April 2016 (has links) (PDF)
In dieser Arbeit wurden Angebotskurven für 22 bedeutende Ölförderländer ermittelt und anschließend zu globalen Angebotskurven aggregiert. Gemäß den ermittelten Angebotskurven sind nahezu alle gegenwärtig in der Förderphase befindlichen Ölprojekte in den Untersuchungsländern auch beim aktuellen Ölpreis von 35 bis 40 US-$ je Barrel unter Berücksichtigung der kurzfristigen Grenzkosten rentabel. Sollte der Ölpreis jedoch in den kommenden Jahren auf diesem Niveau verharren, wird es bis zum Jahr 2024 zu einem Angebotsengpass auf dem globalen Ölmarkt kommen, da zur Deckung der zukünftigen Nachfrage die Erschließung kostenintensiver, unkonventioneller Lagerstätten und von Lagerstätten in tiefen und sehr tiefen Gewässern notwendig ist. Damit es bis zum Jahr 2024 nicht zu einem solchen Angebotsengpass kommt, ist gemäß des ermittelten langfristigen Marktgleichgewichts ein Ölpreis von mindestens 80 (2014er) US-$ je Barrel notwendig.
4

Kurz- und langfristige Angebotskurven für Rohöl und die Konsequenzen für den Markt

Schlothmann, Daniel 08 March 2016 (has links)
In dieser Arbeit wurden Angebotskurven für 22 bedeutende Ölförderländer ermittelt und anschließend zu globalen Angebotskurven aggregiert. Gemäß den ermittelten Angebotskurven sind nahezu alle gegenwärtig in der Förderphase befindlichen Ölprojekte in den Untersuchungsländern auch beim aktuellen Ölpreis von 35 bis 40 US-$ je Barrel unter Berücksichtigung der kurzfristigen Grenzkosten rentabel. Sollte der Ölpreis jedoch in den kommenden Jahren auf diesem Niveau verharren, wird es bis zum Jahr 2024 zu einem Angebotsengpass auf dem globalen Ölmarkt kommen, da zur Deckung der zukünftigen Nachfrage die Erschließung kostenintensiver, unkonventioneller Lagerstätten und von Lagerstätten in tiefen und sehr tiefen Gewässern notwendig ist. Damit es bis zum Jahr 2024 nicht zu einem solchen Angebotsengpass kommt, ist gemäß des ermittelten langfristigen Marktgleichgewichts ein Ölpreis von mindestens 80 (2014er) US-$ je Barrel notwendig.:1. Einleitung 2. Rohöl - Eine naturwissenschaftliche Einführung 3. Charakteristika von Rohölprojekten 4. Historie der Ölindustrie 5. Ökonomik von Rohölprojekten 6. Fallstudien zu den bedeutendsten Förderländern 7. Ermittlung regionaler und globaler Angebotskurven 8. Zusammenfassung

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