dc.contributor.author | Zhou, Yingfang | |
dc.date.accessioned | 2013-12-13T11:51:58Z | |
dc.date.available | 2013-12-13T11:51:58Z | |
dc.date.issued | 2013-12-10 | |
dc.identifier.citation | Pore scale modeling of capillary pressure curves in 2D rock images by Yingfang Zhou, Stavanger : University of Stavanger, 2013 (PhD thesis UiS, no. 213) | no_NO |
dc.identifier.isbn | 978-82-7644-555-8 | |
dc.identifier.issn | 1890-1387 | |
dc.identifier.uri | http://hdl.handle.net/11250/183699 | |
dc.description | PhD thesis in Petroleum engineering | no_NO |
dc.description.abstract | Capillary pressure is relevant to most processes of multiphase flow inporous media, as it controls the pore scale fluids distribution. Reliable
capillary pressure curves are required to model and predict larger-scale multiphase
flow processes; normally these capillary pressures are obtained experimentally using representative core samples. Besides core scale measurements,
pore scale modeling provides another alternative, physically sound approach to compute capillary pressure curves and links the pore
scale properties to laboratory measurements.
Pore scale modeling is a useful tool to enhance our understanding of capillary phenomena and their impact on microscopic fluid flow in porous
media. In this thesis, an existing semi-analytical pore scale model is further
developed to compute two- and three-phase
uid con gurations and
capillary pressure curves at arbitrary wetting conditions in 2D realistic
pore spaces that are extracted directly from segmented rock images. The
simulated capillary pressure curves and
uid con gurations are used as input
in an improved interacting tube bundle model to simulate viscosity and capillary-dominated
ow in porous media. The dynamic e ects of
capillary pressure are further investigated by comparing the equilibrium
static capillary pressure and the simulated dynamic capillary pressure curves.
Based on this research work, seven research papers have been presented
in scienti c journals and international conferences. The main ndings are summarized below:
Two-phase capillary pressure curves computed at uniformly-wet conditions can be scaled by the traditional J-function. The imbibition capillary
pressure curves and fluid con gurations at mixed-wet conditions depend strongly on the initial water saturation and formation wettability.
Based on simulated results, a novel dimensionless capillary pressure function for mixed-wet conditions has been developed to describe more
accurately the variability of formation wettability and permeability in reservoir simulation models.
In water-wet three-phase systems, capillary entry pressure for the nonwetting phase (e.g., gas or CO2) is strongly a ected by the existing initial
fluid con guration of oil and water in the pore space. Generally, the three-phase capillary entry pressure is lower for gas (or CO2) displacing
oil than for gas (or CO2) displacing water in a uniform water-wet system, indicating that CO2 is stored more safely below low-permeable formation
layers in subsurface aquifers than in depleted oil reservoirs. The simulated three-phase fluid con gurations exhibit a similar behavior as that observed in micro-CT experiments; in spreading systems very thin oillayers are present, while in non-spreading systems only a few relatively
thick oil layers exist when gas-oil capillary pressure is low. In the major parts of the three-phase region (except for small oil saturations).
The gas-oil capillary pressure at water-wet conditions seems to be described well as a function of only the gas saturation in the major part
of the three-phase region, despite three-phase displacements in which gas displaces both oil and water occur frequently in individual pore geometries for the non-spreading systems. At small oil saturations, the gas-oil
capillary pressure depends strongly on two saturations, which is particularly
visible in the results for the weakly water-wet spreading system because thin oil layers exist after gas has started to invade pores occupied
by water only.
The simulated saturation pro les under viscous-capillary dominated flow can be explained by the capillary pressure and fluid con gurations, which
exhibit increasingly gradual behavior as the contact angle de ned on the oil-wet solid surfaces increases or the initial water saturation decreases.
Drainage dynamic capillary pressure curves are located at a higher capillary level than the corresponding static curve, whereas for imbibition the dynamic curve is located at a lower capillary level than the corresponding static one, regardless the porous medium wettability. The simulated
dynamic capillary coe cient is a function of saturation and independent
of the incremental pressure step, which is consistent with the results rev
ported in previous studies. The dynamic coe cient increases with decreasing water saturation at water-wet conditions, whereas for mixed- to
oil-wet conditions it increases with increasing water saturation. Imbibition simulations also show that the dynamic capillary coe cient at a
constant saturation increases with decreasing initial water saturation at mixed-wet conditions. | no_NO |
dc.language.iso | eng | no_NO |
dc.publisher | University of Stavanger, Norway | no_NO |
dc.relation.ispartofseries | PhD thesis UiS;213 | |
dc.relation.haspart | Zhou, Y., Helland, J. O., and Hatzignatiou, D. G. 2011: A model for imbibition in pore spaces from 2D rock images. Extended abstract presented at the Pore2Field International Conference held at IFP Energies nouvelles, Rueill-Malmaison, France, November 16-18, 2011. | no_NO |
dc.relation.haspart | Zhou, Y., Helland, J.O., and Hatzignatiou, D.G. 2013. A Dimensionless Capillary Pressure Function for Imbibition Derived From Pore-Scale Modeling in Mixed-Wet-Rock Images. SPE Journal. 18 (2): 296-308. SPE-154129-PA. http://dx.doi.org/10.2118/154129- PA. | no_NO |
dc.relation.haspart | Zhou, Y., Helland, J.O. and Hatzignatiou, D.G.: Pore-Scale Modelling of Water Flooding in Mixed-Wet Rock Images: E ects of Initial Saturation and Wettability, SPE Journal. SPE-154284-PA (in press; posted 05 July 2013). http://dx.doi.org/10.2118/154284-PA. | no_NO |
dc.relation.haspart | Zhou, Y., Helland, J.O., and Jettestuen, E. 2013. Dynamic Capillary Pressure Curves From Pore-Scale Modeling in Mixed-Wet-Rock Images. SPE Journal. 18 (4): 634-645. SPE-154474-PA. http://dx.doi.org/10.2118/154474-PA. | no_NO |
dc.relation.haspart | Zhou, Y., Helland, J. O. and Hatzignatiou, D.G. 2013: Computation of three-phase capillary entry pressures and arc menisci con gurations in pore geometries from 2D rock images: a combinatorial approach, 2013. | no_NO |
dc.relation.haspart | Zhou, Y., Helland, J. O., and Hatzignatiou, D. G. 2013: Simulation of three phase capillary pressure curves directly in 2D rock images, paper IPTC 16547 presented at the International Petroleum Technology Conference, Beijing, China, 26-28 March 2013. | no_NO |
dc.relation.haspart | Zhou, Y., Helland, J. O., and Hatzignatiou, D. G. 2013: Simulation of three phase capillary pressure curves directly in 2D uniformly-wet rock images. | no_NO |
dc.rights | Copyright the author, all right reserve | |
dc.subject | petroleumsteknologi | no_NO |
dc.subject | kapillartrykk | no_NO |
dc.subject | flerfasestrømning | no_NO |
dc.title | Pore scale modeling of capillary pressure curves in 2D rock images | no_NO |
dc.type | Doctoral thesis | no_NO |
dc.subject.nsi | VDP::Technology: 500::Rock and petroleum disciplines: 510::Petroleum engineering: 512 | no_NO |