Simulating water tracer test in naturally fractured reservoirs using discrete fracture and dual porosity models

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Simulating water tracer test in naturally fractured reservoirs using discrete fracture and dual porosity models

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dc.contributor.advisor Sepehrnoori, Kamy, 1951-
dc.contributor.advisor Pope, Gary A.
dc.creator Lalehrokh, Farshad
dc.date.accessioned 2012-11-15T18:26:21Z
dc.date.available 2012-11-15T18:26:21Z
dc.date.created 2005-08
dc.date.issued 2012-11-15
dc.identifier.uri http://hdl.handle.net/2152/18728
dc.description.abstract A naturally fractured reservoir (NFR) is a reservoir with a connected network of fractures created by natural processes such as diastrophism and volume shrinkage (Ordonez et al. 2001). There are two models to simulate this kind of reservoirs: the discrete fracture model and the dual porosity model. In the dual porosity model, the matrix blocks occupy the same physical space as the fracture network and are identical rectangular parallelepipeds with no direct communication between isotropic and homogeneous matrix blocks. However, each fracture and matrix property is defined separately in the discrete fracture model. Another feature of this thesis is tracer testing. In this process, a chemical or radioactive element is injected to the reservoirs, and then it can be traced using the devices, which are designed to detect the tracers. Tracer tests have several advantages such as determining residual oil saturation, identifying barriers or high permeability zones in reservoirs, and providing the information on flow patterns. Limited number of research studies has been done on performing tracer tests in naturally fractured reservoirs. Also because there is not enough information about the advantages and disadvantages of the discrete fracture and the dual porosity models, researchers and engineers lack the expertise to confidently select either the discrete fracture or the dual porosity models to simulate the different types of NFRs. In this thesis, we compared the oil and water productions, and tracer concentration curves in various reservoir conditions, using both the discrete fracture and the dual porosity models. We used the ECLIPSE, which is a commercial software package in the area of petroleum industry, to model a naturally fractured reservoir. We performed a simple waterflooding with two conservative tracers on the reservoirs. The results presented in each section include the graphs of the oil production rate, water production rate, and tracer concentration. In addition, we presented the oil saturation profiles of a cross-section, which includes the production and injection wells. The results illustrated that both the discrete fracture and the dual porosity models are in good agreement, except for a few special cases. Generally, the oil production using the dual porosity model is more than in the discrete fracture model. The major disadvantage of the dual porosity model is that the fluid distribution in the matrix blocks is changing homogenously during the waterflooding period. In other words, ECLIPSE shows a constant value of the oil and water saturations in each time step for the matrix blocks. However, the dual porosity model is 3 to 4 times faster than the discrete fracture model. In the discrete fracture model, the users have complete control in defining the reservoirs. For example, the fracture aperture, fracture spacing, and fracture porosities can be set by the user. The disadvantage of this model is that millions of grid blocks are needed to model a large reservoir with small fracture spacing.
dc.format.medium electronic
dc.language.iso eng
dc.rights Copyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.
dc.subject Naturally fractured reservoir
dc.subject Discrete fracture model
dc.subject Dual porosity model
dc.subject Tracer testing
dc.title Simulating water tracer test in naturally fractured reservoirs using discrete fracture and dual porosity models
dc.description.department Petroleum and Geosystems Engineering
dc.type.genre thesis
dc.type.material text
thesis.degree.department Petroleum and Geosystems Engineering
thesis.degree.discipline Petroleum Engineering
thesis.degree.grantor The University of Texas at Austin
thesis.degree.level Masters
thesis.degree.name Master of Science in Engineering

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