A relationship describing the pressure difference across an interface between two fluids at a static, curved interface. The fact that the capillary pressure saturation curves of nearly all naturally porous. The pore sizes of unconventional reservoir rock, such as shale and tight rock, are on the order of nanometers. Are you ready to attend a petroskills applied reservoir engineering course training class, school or short course. Capillary pressure is a fluidrock property that depends on interfacial tension, contact angle between fluid and solids and capillary pore throat radius. Capillary pressure an overview sciencedirect topics. The accompanying lecture presumes that the reader possesses profound knowledge of reservoir engineering. The prediction of reservoir initial fluid saturations. Applied reservoir engineering training course petroskills re. Capillary pressure is the most fundamental rockfluid property in multiphase flow, just as porosity and permeability are for single phase flow in oil and gas reservoirs. Be familiar with the concept of capillary pressure for tubes as well as porous media and be able to derive the capillary pressure relation for fluid rise in a tube.
The conceptual aspects of the displacement of oil by gas in reservoir rocks are discussed in this section. Introducing imbibition capillary pressure in the assessment of the. Many capillary pressure correlations have been suggested in the literature,15 and they typically have two adjustable parameters. The interfacial forces give rise to what is known as a capillary pressure. A homogenous reservoir rock can be represented by a single capillary pressure curve. Oil migrating into an oilwet reservoir would display a different saturation profile. Pdf in the united states, the organicrich shale resource has. Younglaplace equation schlumberger oilfield glossary. Reservoir engineering is also presented in the context of a modern, multidisciplinary team effort using supporting computer technology. In reservoir engineering we are normally only interested in interconnected porosity, which is the volume of connected pores to total bulk. Describe how capillary pressure can be used to explain macroscopic reservoir phenomena. This difference reflects the ease of invasion by a. Capillary pressure,petrophysics lecture 4, petroleum. This volume is the fourth within the series of the reservoir engineering textbooks provided by the association of professor heinemann doctorate group.
Dynamic capillary pressure, fluid flow, tight gas reservoir, twophase. Capillary pressure is the difference in fluid pressure across an interface between two fluids in a confined volume. Capillary pressure is important in reservoir engineering because it is a major. Show how collecting capillary pressure data can actually save money.
Simultaneous existence of two or more fluid phases in a pore space of a reservoir rock requires clear understanding and characterization of the following terms so that the production potential of a given hydrocarbonbearing formation can be evaluated interfacial tension wettability capillary pressure. This difference reflects the ease of invasion by a wetting fluid. Practical reservoir engineering and characterization. Pdf capillary pressure measurement using reservoir fluids in a. In fluid statics, capillary pressure is the pressure between two immiscible fluids in a thin tube see capillary action, resulting from the interactions of forces between the fluids and solid walls of the tube. In addition to the geological heterogeneity caused by variation in poresize distributions with position in the reservoir, several other aspects might effect the complexity.
As ancillary data for assessment of relative permeability data. Introducing imbibition capillary pressure in the assessment of the smoerbukk and. Capillary pressure is the pressure difference existing across the interface separating two immiscible fluids. Tarek ahmed, in reservoir engineering handbook fifth edition, 2019. Immiscible gas injection in oil reservoirs petrowiki. To measure capillary pressure of unconsolidated sand packs. Dynamic effect of capillary pressure in tight gas reservoir. Discuss the various choices available for measuring relative permeability in the. The first two topics are discussed in this section. By contrast, a heterogenous reservoir will have a family of rock types, each with its own capillary pressure curve. Capillary pressure results from interactions of forces acting within and between fluids and their bounding solids.
Given that modern reservoir engineering is largely centered on numerical computer simulation and that reservoir engineers in the industry will likely spend much of their professional career building and running such. Capillary pressure is an important characteristic of rock that helps reservoir engineers determine where hydrocarbons and water are located in the subsurface. Capillary transition zones from a core analysis perspective. When adhesive forces are greater than cohesive forces, the liquid is said to be wetting. Oilwater capillary pressure and relative permeability are significant data in reservoir engineering li et al. Shale and tight reservoir rocks have pore throats on the order of nanometers, and, subsequently, a large capillary pressure. Knowledge of reservoir porosity, permeability, and capillary pressure is essential to.
Determining water saturation from capillary pressure in. The university of tulsa petroleum engineering department. To this end, li and horne6 proposed a capillary pressure model for the imbibition case in 2001. Capillary pressure is one of input data in reservoir simulation process which should be considered in history matching procedures.
Improved characterization and modeling of capillary transition. Capillary pressure reservoir engineering pe02 studocu. Empirically it has been found that the brookscorey capillary pressure model is appropriate to the drainage case. Petrophysicists will use capillary pressure curves as the basis for deriving a water saturation versus height relationship for a reservoir. This characteristic can be measured from core samples analyzed in a laboratory setting and compared to other measurements taken in the field. Capillary pressure data are obtained on small core samples that represent an extremely small part of the reservoir and, therefore, it is necessary to combine all capillary data to classify a particular reservoir. Additionally capillary pressure was found to lead to bubble point suppression, reduction in oil density and viscosity, and increase in gas density and viscosity. Capillary pressure curve, simulation, hysterises, water coning, well production. Practical reservoir characterization expertly explains key technologies, concepts, methods, and terminology in a way that allows readers in varying roles to appreciate the resulting interpretations and contribute to building reservoir characterization models that improve resource definition and recovery even in the most complex depositional environments. Relative permeability, petrophysics lecture 5, petroleum.
Fundamentals of applied reservoir engineering 1st edition. One of these sources can be the assumption of equilibrium between gravity and capillary forces within the reservoir. Abtahi department of petroleum engineering and applied geophysics norwegian university of science and technology august, 2000. Bakken fluid phase properties were found to deviate from bulk behavior up till pore radii of approximately 100 nm. Some systems are strongly waterwet, while others are oilwet or neutrally wet. Department of petroleum engineering, university of ibadan, ibadan 200284. Effect of large capillary pressure on fluid flow and. Any subsurface professional that is using capillary pressure data in petrel or techlog.
In petroleum engineering, the leverett jfunction is a dimensionless function of water saturation describing the capillary pressure. Capillary pressure theory and introduction and how can you determine it in the laboratory. One parameter expresses the pore size distribution and hence the curvature of the pc curve, the other the actual level of the capillary pressure, i. The shape of the curve depends on pore sizes, size distribution, and fluid properties. To my gorgeous wife shanna, and my beautiful children jennifer justin brittany carsen reservoir eng fob 20011029 16. Determination of capillary pressure and relative permeability from. For the simulation of mixed co2water injection into the geothermal reservoir, the reservoir pressure is between 205 and 250 bars and, therefore. The open petroleum engineering journal, 2014, 7, 7179. Capillary pressure and relative permeability correlations for transition zones of carbonate reservoirs article pdf available august 2017 with 743 reads how we measure reads. Brookscorey burdine equations for relative permeability based on the combination of the burdine relative permeability equations and the brooke corey capillary pressure. An extensive manual and set of references are included. The thermodynamic properties of insitu hydrocarbon mixtures in such small pores are significantly different from those of fluids in bulk size, primarily due to effect of large capillary pressure. The role of capillary pressure curves in reservoir. The wettability properties, capillary pressure, phase saturation, and rela.
Capillary pressure curves directly determine the irreducible water saturation. Oil recovery mechanisms and the material balance equation jan 2000. Spe 89874 generalized capillary pressure and relative. This, and the related gas and water saturations are controlled by capillary pressure. Capillary pressure hysteresis fundamentals of fluid flow. The petrel reservoir engineering core provides access to the standard petrel platform, which includes. Capillary pressure is used both in petrophysical and reservoir engineering applications such as saturation height modeling altunbay et al. In the discussion of capillary pressure, we will first examine surface energy and wettability, and then go on to derive a general expression for capillary. These include both cohesive forces surface and interfacial tension and adhesive liquidsolid forces. Wettabilities of reservoir systems are categorized by a variety of names.
Evaluating capillary pressure of potential reservoir and seal rocks is important because. This relationship defines the capillary pressure difference at such an interface. The latter usually constitute the bulk of the input data and are the most difficult to accurately determine. Wettability effects on capillary pressure, relative permeability, and. Brief overview of capillary theory, lab techniques, converting data from lab values to reservoir capillary pressure and height above free water and saturation height model concepts based on petrophysical rock types. Impact of capillary pressure and critical properties shift. A website about reservoir engineering for non reservoir engineers. When cohesive forces exceed adhesive forces, the liquid is nonwetting. Capillary pressure can serve as both an opposing or driving force for fluid transport and is a significant property for research and industrial purposes namely microfluidic design and. Capillary pressure and saturation height model concepts. Abstract capillary pressure and relative permeability are important parameters in reservoir engineering.
An efficient method for determining capillary pressure and relative. The capillary pressure is dependent on the interfacial tension, pore size, and wetting angle. If the wettability of the system is known, then the capillary pressure will always be positive if it is defined as the difference between the pressures in the nonwetting and wetting phases. The permeability of the reservoir rock can alter the capillary pressure curve. Ift, a fluid experiences a force of pressure known as capillary pressure through the narrow capillaries of a porous medium and rises up or down from the free fluid level. Explain how capillary pressure is a combination of several related phenomena. Wettability effects on capillary pressure, relative. Capillary pressure free download as powerpoint presentation.
Use basic reservoir engineering principles, including flow through porous media, relative permeability, nodal analysis and multiphase flow to evaluate single. Understand and apply reservoir simulation to analyze reservoir performance and optimize reservoir development. It is generally agreed that the pore spaces of reservoir rocks were originally filled with water, after which oil moved into the reservoir, displacing some of the water and reducing the water to some residual saturation. Capillary forces are one of effective parameters in hydrocarbon reservoirs which are notable in the porous media. Capillary pressure correlation for mixedwet reservoirs.
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