Chapter 7 PDF
Chapter 7 PDF
Chapter 7 PDF
RESERVOIR ENGINEERING 1
SCOPE
• In this case a subsurface sampler is lowered into the well and kept
opposite the producing layer for a sufficiently long time.
• A sample of oil and gas is taken from the separator connected with
the well
• The surface oil and gas samples are recombined in the laboratory
on the basis of the producing GOR.
Vertical and Horizontal Separator Gas Sampling
Separators
Separator Liquid Sampling Separator Liquid Sampling
by Gas Displacement by Water Displacement
SAMPLING WET GAS AND GAS CONDENSATE
SYSTEMS
Condition in separator
SAMPLING WET GAS AND GAS CONDENSATE
SYSTEMS
• Phase Behaviour
Four main PVT tests for oil systems plus associated compositional analysis:
(i) the flash vaporisation or relative volume tests.
(ii) the differential test.
(iii) the separator tests.
(iv) viscosity measurements
(v) compositional measurements.
Simple Schematic of PVT Facility for Oil Tests
Flash Vaporisation
(Relative Volume Test)
• The thermal expansion factor (β) can then be calculated from the
volume withdrawn.
Flash Vaporisation (Relative Volume Test)
• The compressibility of the oil phase above the bubble point can
now be calculated from the graph
• When the reservoir pressure falls below the bubble point the
process of gas liquid separation in the reservoir is one of a
constant changing system
• PVT process has been designed in an attempt to provide a means
of in part simulating the changing systems as separation occurs
within the reservoir below the bubble point.
Differential Vaporisation
Procedure:
• Starting point is oil in the PVT cell at
its reservoir bubble point,
• Fluid is displaced from the PVT cell
ensuring that the PVT cell contents
remain at bubble point pressure.
• The gas and liquids are collected from
the separation stage(s) and their
respective properties measured.
• The final stage is at stock tank
conditions.
• The resulting fluid is termed stock
tank oil.
Single /Double Separator Tests ?
Given the experimental data in Table, verify the oil density values
at 4,000 and 6,500 psi.
Solution
Smoothing technique