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The permeability of a petroleum reservoir is one of the most influential parameters in determining the production capabilities of a producing formation. Permeability is a measure of the ability of a fluid to flow through a porous media when subjected to a differential pressure and is mathematically equated by Darcy’s law. In equation form:
Q=kAdp/(uL)
where:
Q = Flow Rate
k = Permeability
A = Cross Sectional Area
dp = Differential Pressure
u = Viscosity
L = Length
Cross sectional area and length are governed by the reservoir geometry and cannot be changed. Fortunately, reservoir pressure, fluid viscosity, and permeability may be modified by petroleum operations. To improve the production potential of a reservoir, differential pressure may be increased by water flooding and/or fluid viscosity may be reduced chemically. Similarly, reservoir permeability may be enhanced by acidizing techniques, or even more significantly, reduced during drilling, cementing, and workover operations. Any fluid that comes in contact with the producing formation may significantly reduce the permeability and greatly affect the production capabilities of the reservoir. Studies are typically conducted on core specimens to determine how drilling, cementing, and workover fluids affect the permeability of the formation. The Reservoir Permeability Tester was developed to evaluate how fluids affect the permeability of a core specimen. In addition, the unit may be used to evaluate acidizing techniques and to develop typical Acid Response Curves (ARCs).
Method of Operation:
A core specimen is placed into the viton core sleeve and then inserted into the “Hassler” test cell. Confining pressure is placed upon the sleeve via an air-driven hydraulic pump. Accumulators are filled with the desired test fluids and the necessary back pressure, dependent upon the test temperature, is placed upon the system. The temperature controller is set appropriately and the test cell is allowed to reach temperature. Valves are positioned in such a manner that the test fluid is driven through the core in the forward direction and the fluid delivery pump is activated. Differential pressure across the length of the core is measured via a pressure transducer and documented via the Data Acquisition System. If desired, the test fluid may be driven in the reverse direction by adjusting the control valves. Other test fluids are quickly and easily accessible from other accumulators. Nitrogen may be used for gas testing.
A typical test sequence could involve: establishing effective permeability and 100 percent saturation with a brine, reversing flow direction with oil to establish an irreducible water saturation, contaminating the core in the forward direction with possibly a drilling filtrate, and finally reversing the flow direction with oil to examine the return permeability. Several sequences could be performed to simulate a producing reservoir during each phase/stage of production.
Features and Specifications:
- “Hassler” test cell utilizes 1.5" diameter cores
- Core lengths from 2" to 6"
- Cell temperature (400ºF) maintained via internal heaters
- Test fluid is heated via a heat exchanger
- Differential pressure transducer accurate to 0.25% of full scale
- Duplex pump delivers test fluid at up to 5,000 psi
- Flow direction of test fluid easily reversed by the use of valves
- Hydraulic pump provides confining pressures of 5,000 psi
- All wetted components constructed of 316 SS
- Three 1000 cc 316 SS accumulators with piston
- 316 SS dome loaded back pressure reg. for single phase flow
Option:
A Digital Acquisition System (DAS) is available for the Model 340. This option utilizes an IBM-compatible computer with a Pentium
microprocessor, color monitor and printer to measure, record, display, and print all necessary data.
Instrument Requirements:
- 40 psi water source
-
1000 psi N2 source
- Drain for fluid
- 220 Volt, 50/60 Hz, 15 Amp electrical power source
Size: 24 x 60 x 44 inches (61 x 152.4 x 111.8 cm)
Weight: 350 lbs (159 kg)
Optional:
#127-02 Two Years Spare Parts
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