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Refrigerated Centrifuge - RC
VINCI TECHNOLOGIES – http://www.vinci-technologies.com Page 1
Determination of Capillary
pressure & relative permeability
curves
With Refrigerated Centrifuge
Multi speed centrifuge experiments
Introduction
As the porous diaphragm method (see Vinci’s CAPRI), the
centrifuge method is a commonly used method for determining
the capillary pressure properties of reservoir rocks.
The procedure begins with a core sample which is placed in a
centrifuge tube. The system is rotated at a number of different
speeds selected to cover pressure differences between phases
required for the particular cores. At each step, the rate of rotation
is maintained constant until phase stabilization.
Either Drainage or Imbibition experiments can be held as shown
in the pictures below.
Centrifuge force
Imbibition experiment
Core saturated with
the non-wetting fluid Sample
containment cup
Calibrated
receiving tubeWetting fluid
Non-wetting fluid
VINCI TECHNOLOGIES Parc de l'Ile, 27B rue du Port,
92022NANTERRE Phone: 331 41 37 92 20
e-mail: [email protected]
http://www.vinci-technologies.com
Refrigerated Centrifuge - RC
VINCI TECHNOLOGIES – http://www.vinci-technologies.com Page 2
The centrifuge technique for measuring relative permeability is a simple
extension of the centrifuge technique for measuring capillary pressure.
The fluid produced as a function of time for each rotational speed is
analyzed to determine the relative permeability curves.
Data collection is therefore no more complicated than for the capillary
pressure case except that the frequency of data capture is greatly
increased, particularly just after the speed of rotation has been changed.
Refrigerated centrifuge (RC)
The RC is a refrigerated centrifuge enabling automatic
determination of capillary pressure & relative permeability curves
on six core sample.
Custom designed core holders offer the ability to spin core plug
samples. Each coreholder is equipped with a sample containment
cup and a calibrated receiving tube.
A unique feature is that Vinci’s coreholder can accommodate
either 1 or 1.5’’ diameter cores. The same coreholder can be used
either for drainage of for imbibition experiments.
Refrigerated Centrifuge - RC
VINCI TECHNOLOGIES – http://www.vinci-technologies.com Page 3
Drainage / Imbibition Core Holder / Amott cell
Spontaneous Imbibition and drainage measurement are made using
Amott cells
The centrifuge is equipped with a high resolution digital camera
system allowing measurement of displaced fluid volumes in each of the
cells sequentially.
Thanks to a 1360 x 1024 pixel resolution, the interface level is detected
with an accuracy of less than 0.1 mm i.e. 0.03 cc for a 20 mm receiving
tube.
Dedicated software automatically detects the interface between the
fluids and records the volume production.
A unique feature of RC is the very important length of the
centrifuges arms. Compared to some others centrifuge, RC can
achieve important capillary pressure at relatively low rotational
speed. Thanks to this particularity, the rotation speed is stable
even for high capillary pressures and the interface detection
remains perfect for any rotation speed.
Gas Water Interface
1mm wide Floating disc
Lower end of the reciving
tube
Water / Gas Drainage
experiment
Refrigerated Centrifuge - RC
VINCI TECHNOLOGIES – http://www.vinci-technologies.com Page 4
The great speed stability of RC and the accuracy of interface
detection allows for high quality production curves.
Overburden core holder
For overburden experiments, at reservoir conditions of pressure
(5,000 psi), dedicated core holders can be provided.
Confining pressure can be
applied prior to the test using a
manual pump.
The loading mode is hydrostatic,
therefore, axial and radial
pressure are equivalent.
The same core holder can be used
both for drainage and imbibition
test
The same core holder can be used
for 1 or 1.5’’ diameter cores.
Refrigerated Centrifuge - RC
VINCI TECHNOLOGIES – http://www.vinci-technologies.com Page 5
Simulation package
RC is provided with a dedicated simulation package. CYDAR includes a
special module for centrifuge acquisition data. CYDAR automatically
collects the production curve and calculates instant saturation and
capillary pressure.
This simulation package has been developed in collaboration with core
analysis specialists; it’s customer friendly software accurate and
powerful.
CYDAR uses the most recent methods developed and tested in research
laboratories and published in the proceedings of the Society of Core
Analysis.
For each experimental curve, CYDAR proposes 6 types of different
fit (linear, splines, bi-exponential, etc.). Kr and Pc determination is
made by numerical history matching. The modules allows for
classical calculations (Hagoort, JBN, etc.) as well as accurate
simulations.
Refrigerated Centrifuge - RC
VINCI TECHNOLOGIES – http://www.vinci-technologies.com Page 6
Technical Specifications
Item Type / model / specification
Core holder:
Number of Core Holder: 6
Core Ø: 1 or 1.5’’
Core length: Up to 4 ” for atm. coreholder
Up to 2.5” for overburden core holder
Capillary pressure:
Oil-water drainage: 0.0 to 14.7 bar
(0 to 213 psi)
Oil-water imbibition: – 0.0 to – 15.9 bar
(–0 to – 230 psi)
Air-water drainage: 0.0 to 44.1 bar
(1 to 639 psi)
Air-water imbibition: – 0.1 to – 47.628.1 bar
(–1 to – 690 psi)
Speed:
Speed: from 200 to 4,500 rpm
Speed regulation: ± 1 rpm
Speed ramp: Available
Temperature: From 5° to +90°C
Larger radius: 26 cm
Accuracy on reading: 0.01cc