Model: TR RPD100 relative permeability determinator

Summary:

Relative permeability - relative permeability of some phase fluid refers to the ratio of effective permeability and absolute permeability of the phase fluid when multiphase fluid coexists. The denominator of the ratio could be air absolute permeability, 100% water or oil permeability and oil permeability in the state of bound water. Relative permeability  reflects the change rule of two phase fluid each seepage ability in the oil layer, which is the development and production index that forecasting oil field water drive and is the very important index of dynamic change condition.

TR RPD100 relative permeability determinator is fit for the determination of two-phase fluid relative permeability in cementation sandstone rock sample, the device has the following function:

(1) The determination of steady-state techniques oil-water relative permeability

The foundation is Vidarcy percolation theory, and ignore capillary pressure and action of gravity, on the condition of constant total flow, inject the oil water in certain flow proportion meanwhile into the rock sample in constant speed, when rock core both ends differential pressure and oil, water flow are stable, rock sample containing water saturation don’t change, at this time the distribution of oil, water in rock sample pore is uniform, reaching stable state, the effective permeability value of  oil and water is constant. So could use determining rock sample inlet outlet pressure differential and oil, water flow, directly calculate the effective permeability and relative permeability value of oil, water of rock sample by Darcy's law. Changing the oil water injection flow proportion, then could obtain a series of oil, water relative permeability in different containing water saturation , and according to this draw oil- water relative permeability curve of rock sample.

(2) unsteady state the determination of oil water relative permeability

Unsteady state method oil – water relative permeability is based on 

 Buckley-Leverett one dimensional-two phase water drive oil frontal advancing theory. Ignoring the capillary pressure and action of gravity,

Assuming that two phase immiscible fluid and incompressible, rock sample in any cross section oil water saturation is uniform. During testing, not inject two kinds of fluid in rock core at the same time, but make the rock core saturated with one fluid in advance, displace with other fluid. During the process of water driving oil ,the distribution of oil water saturation in porous medium is the function of distance and time, the process is called non-stabilization process, consistent with Oilfield development process. According to the requirement of simulated conditions, take test of constant differential pressure or constant speed water driving oil on oil deposit rock sample, record the output of every kind of fluid at the outlet of rock sample and pressure difference at the both ends of rock sample with the change of time, obtaining oil-water relative permeability by calculating in “J．B．N” method, and draw the relation curve of oil-water relative permeability and water saturation.

Main technical parameters：

(1) Operating temperature: ambient temperature-80℃

(2) Natural core holding unit: core specification: Φ25×25—80mm, displacement pressure: 40MPa. ring seal pressure: 50MPa.

(3) working fluid: water sample, oil sample.

4. Installation composition:RPD100 relative permeability measurement device mainly include oil phase injection system, water phase injection system, core holding unit, confining pressure system, back pressure system, vacuum system, temperature control system, pressure measuring system, outlet metering system, pipe valves work piece system, data sampling and processing system, etc.
Among this:Oil Phase injection system: Oil Phase injection system mainly includes domestic constant speed and pressure pump, oil vessel, piston vessel,filter, etc. Water phase injection system: mainly includes domestic constant speed and pressure pump, water container , filter, etc. core holding unit system: core specification Φ25×25—80mm, displacement pressure: 40MPa, ring seal pressure: 50MPa. confining pressure system: Adopt confining pressure tracking system, this system has manual operation and automatic function, also has the function of tracking differential pressure, pressure, etc, stable performance. Pressure range 0-65MPa, the precision is not less than 0.2MPa. Confining pressure automatically track with the changing of internal pressure, thus ensure that confining pressure and internal pressure keep fixed difference value, its characteristic is that pressure difference , error value, the zero point of sensor and correction of full range, etc, these parameters could be adjusted at any time, has manual, electric, constant pressure, tracking function, fasting tracking speed, accurate tracking difference, etc, which is the perfect auxiliary instrument in laboratory.Back pressure system: this system is composed of back pressure pump, back pressure buffer, High accuracy back pressure valve, back pressure buffer could improve the precision of back pressure control, ensuring the accuracy of measurement. The back pressure control system is 1 set in total.
High precision back pressure valve adopts thin sheet structure , adopt copy Canada DBR company BPR product structure form, mainly composed of stainless steel sheet, valve needle, valve seat, valve upper and lower body, seal ring, this valve has these advantage of high  adjustment sensitivity, high pressure resistance（32MPa）, high control precision, light weight, etc. Vacuum system: composed of vacuum pump , vacuum gauge, vacuum buffer vessel and valve pipeline, vacuum degree -0.1MPa, vacuum pump: Model 2XZ-4 Vacuum buffer vessel: ZR-5, 600mL, transparent and visible.Temperature control system: mainly composed of two parts, container, core holding unit constant temperature box temperature control systemand oil water measurement constant temperature box.Container and model constant temperature box temperature control:Adopts air bath heating, constant temperature box the dimensions of the working chamber is 1400×900×800, temperature range: room temperature～180℃, digital display automatic temperature control, precision±0.5℃, adopt imported temperature controller, with PID regulation, hot wind convective circulation, inside adopts δ=1.2mm, outside surface coating. Oil and water two phase measurement incubator: adopts air bath heating, the working dimension of incubator is 600×900×800, temperature range: room temperature～80℃, digital display automatic temperature control, precision±0.5℃, adopt imported temperature controller, with PID regulation, inside adopts δ=1.2mm, outside surface coating. Pressure measurement system: include upper current pressure sensor, lower current pressure sensor, pressure digital display secondary meter,circling pressure sensor, upper current pressure sensor measuring range is 50MPa、20MPa, the quantities are 4 sets, lower current pressure sensor measuring range is 40MPa、10MPa, the quantities are 2 sets ,the precision is 0.1%, adopt Switzerland imported pressure sensor brand. Outlet measurement system: Adopt oil water two phase measurement system , the system use  intelligent electronics liquid level controller, high precision control oil water separation interface. Production water uses controller activating pneumatic valve to discharge, calculate the production by electronic balance, output oil control liquid level of oil by laser liquid level, and microcomputer control precision oil pump, combination of both, precisely measure oil production. Main technical index:measuring accuracy: output oil measuring accuracy 0.1ml, output water measuring precision 0.01mlmeasuring display: has oil, water instantaneous delivery, accumulative flow indication, RS232 port.

Main technical parameters

(1) Operating temperature: ambient temperature-80℃

(2) Natural core holding unit: core specification: Φ25×25—80mm, displacement pressure: 40MPa. ring seal pressure: 50MPa.

(3) working fluid: water sample, oil sample.