ANSI API RP 13M-6-2020 pdf free download – Procedure for Measuring Leakoff of Completion Fluids Under Dynamic Conditions.
4ldentification of test parameters (linear flow cells)
4.1General
All calibrations shall be performed in accordance with the manufacturer’s recommendations.
4.2Temperature
4.2.1General considerations
Temperatures shall be measured to within ±1 “C(+2 °F) and stabilized to within 13 “C(±5 °F) of the testtemperature.
4.2.2Test temperature
The test temperature is the simulated temperature as defined by the fluid and cell temperatures.
4.2.3 Fluid temperature
Fluid temperature is the temperature of the test fluid measured at the fluid inlet.
4.2.4Cell temperature
Cell temperature is the internal cell temperature representing the core temperature.
4.3Pressure
4.3.1 Test pressure
Test pressure is the differential fluid pressure across the core length. lt may be measured by a differentialpressure transducer or calculated by subtracting the backpressure from the fluid pressure. lt shall becontrolled at 5 % of the design pressure.
4.3.2 Fluid pressure
Fluid pressure is the pressure at the core face.
4.3.3 Backpressure
Backpressure is the pressure of the filtrate as it exits the core.
4.3.4Confining pressure
The confining pressure is the pressure used to seal the core if a Hassler sleeve is used.
4.4Test duration
The test begins when the differential fluid pressure is applied and shall continue for a minimum of 60 min.
4.5Shear rate
The shear rate of the test fluid across the core face shall be 40 s-1±25 %.
4.6Permeability
Using a compatible fluid, determine the permeability of the core prior to the test.
Permeability should be calculated as per Darcy law as referenced in API 19D.
4.7Fluid shear-history simulator (optional)
Shear-sensitive fluids may be conditioned through a shear-history simulator as described in ls0 13503-1and specified by the following parameters:
a)tubing length;
b)tubing inside diameter;
c)flow rate.
4.8Heat-up rate
Within 15 min or less, the fluid temperature at the inlet shall be no lower than 5 % below and no higher than3 ℃ (5 °F) above the desired test temperature. The inlet temperature shall be measured and recorded at apoint close to the inlet port.
5Test procedure5.1Core preparation
Mechanical preparation of the core shall be carried out so as to minimize any alteration of its permeability(such as by grinding and polishing the core surface). The core shall be saturated with the base fuid or asynthetic formation filuid(examples include KCI,NHaCl or other brines). if the formation fiuid is not known, thecore shall be saturated using a non-reactive solution.
5.2Round cell
5.2.1 Prepare a core with minimum dimensions of 25,4 mm (1 in) in length by 25,4 mm (1 in) in diameter.5.2.2Saturate the core and record liquid permeability.
Permeability should be calculated as per Darcy’s law as referenced in API19D.
5.2.3 Prepare the test fluid and record fluid properties (for example in accordance with ISo 13503-1).
5.2.4Set the backpressure, typically 690 kPa (100 psi) or greater, to satisfy a desired pressure differentialacross the core during the test (for example a minimum pressure differential of 6 9oo kPa (1 000 psi) fortests on low-permeability cores).
5.2.5 Heat the cell to the test temperature.
5.2.6 Fluid should enter and exit the cell in a uniform flow regime so as to minimize entrance and exiteffects. The distance between the core face and any loop curvature before fluid enters or exits the cellshould be at least 2,5 times the diameter of the loop.
5.2.7 Initialize flow across the core face at the desired shear rate with the leakoff valve closed.
5.2.8 Monitor fluid temperature，fluid rate，pressure differential and fluid properties such as pH andviscosity before the fluid enters the cell.
5.2.9 Open the leakoff valve and start collecting leakoff fluid volumes at a minimum frequency of one datapoint per minute for at least 60 min. The volume is collected in a container, making sure that evaporation isminimized (the volume may be calculated from fluid mass by collecting fluid in a tared container).ANSI API RP 13M-6 pdf download.