- Branża: Oil & gas
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A test to determine the amount of clay-like materials in a water-base drilling fluid based on the amount of methylene blue dye absorbed by the sample. Results are reported as "MBT" and also as "lbm/bbl, bentonite equivalent" when performed to API specifications.
Industry:Oil & gas
A test performed by the mudlogger or wellsite geologist, used to calculate sample lag. The lag period can be measured as a function of time or pump strokes. Acetylene is commonly used as a tracer gas for this purpose. This gas is generated by calcium carbide, a man-made product that reacts with water. <br>Usually, a small paper packet containing calcium carbide is inserted into the drillstring when the kelly is unscrewed from the pipe to make a connection, and the time is noted, along with the pump-stroke count on the mud pump. Once the connection is made and drilling resumes, the packet is pumped downhole with the drilling fluid. Along the way, the drilling fluid breaks down the paper and reacts with the calcium carbide. The resulting acetylene gas circulates with the drilling fluid until it reaches the surface, where it is detected at the gas trap, causing a rapid increase or spike in gas readings. The time and pump-stroke count are again noted, and the cuttings sample lag interval is calculated.
Industry:Oil & gas
A term used to describe the beginning of thickening of a cement slurry during the thickening-time test, often abbreviated as POD. For some slurries, the POD is used as the thickening time.
Industry:Oil & gas
A test for oil-base and synthetic-base muds that indicates the emulsion and oil-wetting qualities of the sample. The test is performed by inserting the ES probe into a cup of 120掳F (48. 9掳C) mud and pushing a test button. The ES meter automatically applies an increasing voltage (from 0 to 2000 volts) across an electrode gap in the probe. Maximum voltage that the mud will sustain across the gap before conducting current is displayed as the ES voltage. The modern ES meter has sine-wave circuitry, whereas older meters used square-wave circuits. (The older units should not be used because they do not correctly address the theory described in the reference below. ) The ES sine-wave design and meaning of ES readings have been studied and were found to relate to an oil mud's oil-wetting of solids and to stability of the emulsion droplets in a complex fashion not yet understood. <br><br>Reference:<br>Growcock FB, Ellis CF and Schmidt DD: "Electrical Stability, Emulsion Stability, and Wettability of Invert Oil-Based Muds," SPE Drilling & Completion 9, no. 1 (March 1994): 39-46.
Industry:Oil & gas
A test intended to indicate the presence of free oil when drilling fluid, drilled cuttings, deck drainage, well treatment fluids, completion and workover fluids, produced water or sand or excess cement slurry are discharged into offshore waters. Two types of sheen tests are mandated by EPA under NPDES permits. The visual sheen test consists of an observation made when surface and atmospheric conditions permit watching the ocean water for a sheen around the point where the discharge entered the water. When the conditions do not permit visual observations, a static sheen test is mandated by NPDES permits and the protocol published by US EPA. This test uses sea water in a shallow pan (not more than 30 cm deep) with 1000 cm<sup>2</sup> surface area. Either 15 cm<sup>3</sup> of fresh mud or 15 g fresh cuttings are injected below the surface of the water. An observer watches for up to 1. 0 hour for a silvery, metallic, colored or iridescent sheen. If sheen covers 50% of the area, the mud or cuttings cannot be discharged. <br><br>Reference:<br>Federal Register 57, no. 224 (November 19, 1992): 54652-57. <br><br>Weintritt DJ, Qaisieh NS and Otto GH: "How To Improve Accuracy in the EPA Static Sheen Test," Oil & Gas Journal 91, no. 18 (May 3, 1993): 77-83.
Industry:Oil & gas
A test for water mud or oil mud, generally known as the retort test. Proper procedures for retort tests have been published by API. The test is a distillation of a mud sample that measures condensed oil and water collected from the retort. Data obtained are: (1) vol. % water, (2) vol. % oil and (3) vol. % retort solids. Retort solids is the volume that was not recovered as a liquid. Three sizes of retort apparatus are available: 10-, 20- and 50-cm<sup>3</sup> mud sample size. Some designs have a small oven in the carrying case to heat the sample (the preferred method for oil muds) while others use a blade heater that goes into the mud sample. Retorts should be heated to around 700掳F (371掳C) to be effective.
Industry:Oil & gas
A term used to describe particle whose size is between 2 and 74 micrometers (200 mesh).
Industry:Oil & gas
A term used to describe an emulsion in a water-base mud in which the oil phase is internal (as in milk), and water is external.
Industry:Oil & gas
A term used by US Environmental Protection Agency (EPA) to specify the elements cadmium (Cd) and mercury (Hg). In a broader sense, the term can be used to specify other metals for which environmental concerns exist, such as copper, lead, chromium, nickel, arsenic and zinc. NPDES permits for offshore drilling set limits on Cd and Hg concentrations in barite that go into drilling fluids to be discharged offshore. Cadmium sulfide and mercury sulfide are minerals associated with barite ores. Maximum concentrations are Cd >= 1 and Hg >= 3 ppm (mg/kg). <br>Reference:<br>Recommended Practice Standard Procedure for Laboratory Testing of Drilling Fluids, 5th ed. Washington, DC, USA: American Petroleum Institute, 1995.
Industry:Oil & gas
