DWY-2 Electrical Stability Tester

I. Overview

The Electrical Stability Tester (DWY-2) is a sine wave instrument, manufactured in accordance with the American Petroleum Institute (API) "Recommended Practice Standard Procedure for Field Testing Oil-Based Drilling Fluids" 13B-2. It is precise, compact, and portable. Used routinely in the field and laboratory to measure the relative electrical strength of drilling fluids with a continuous oil phase. DWY-2 tester consists of the testing instrument and a probe, powered by two common 9-volt alkaline batteries. The dielectric breakdown voltage is key to the conductivity of the drilling fluid. The DC power from the batteries supplies an AC voltage to the electrodes at a low frequency.

The size of the electrical stability tester, the spacing between the electrodes, and the current have been standardized. Both electrodes are of the same size, spaced 0.061 inches apart; the current is set to 61μA. A continuously increasing voltage, with a fixed frequency of 340 ± 10Hz and an amplitude that rises steadily, is applied to the electrodes. When the electrodes are immersed in the drilling fluid, if the current between them begins to conduct and reaches 61μA, the voltage stops increasing automatically, and the peak voltage reading stabilizes. This peak voltage is recorded and displayed as the dielectric breakdown voltage.

The electrical stability value decreases as the test temperature increases. The recommended API test temperature is 120 ± 5°F (49 ± 3°C). Chemical composition and the shearing process of the drilling fluid control the absolute value of DWY-2.

Since the DWY-2 for oil-based drilling fluids is complex and variable, the main conditions affecting the electrical stability of drilling fluids include:

(1) Resistivity continuity (usually referring to heavy oil)

(2) Conductivity discontinuity (usually water droplets and dissolved salts)

(3) Solid particles with suspended properties

(4) Temperature

(5) Droplet size

(6) Different types of emulsifiers

(7) Dielectric properties of the liquid

(8) Shear history of the sample

Therefore, interpreting the oil-wet state from a single electrical stability test result does not represent the performance of the drilling fluid. Due to the many factors influencing the measurement, the absolute value from a single measurement is not meaningful. It is recommended to perform multiple tests and use the results to establish a trend chart. This trend chart can accurately reflect the properties of the drilling fluid and provide a basis for drilling fluid treatment.

II. Safety Principles

When operating and maintaining the electrical stability tester, adhere to laboratory operating and procedural standards. Some test samples may pose potential hazards or contain flammable materials. When using such samples, ensure good ventilation and use a fume hood.

Powered by two 9V alkaline batteries or AC voltage (100-240V, 50/60Hz). The following safety principles should be observed during operation:

1. The probe can carry voltages up to 2000V; do not touch the probe during testing.

2. Users should keep the probe away from electrical grounding points.

3. Exercise caution when testing aqueous solutions. The probe should be immersed in the aqueous solution before starting the test. Do not start the test and then immerse the probe. Sudden immersion can generate a current of up to 61μA.

Note: The above prices are for industry reference/intent deposit only. The actual transaction price will be determined based on the specific instrument model, quantity, and market fluctuations. For accurate pricing, please inquire by phone or in person.