- Settore: Oil & gas
- Number of terms: 8814
- Number of blossaries: 0
- Company Profile:
A conical-shaped funnel, fitted with a small-bore tube on the bottom end through which mud flows under a gravity head. A screen over the top removes large particles that might plug the tube. In the test standardized by API for evaluating water-base and oil-base muds, the funnel viscosity measurement is the time (in seconds) required for one quart of mud to flow out of a Marsh funnel into a graduated mud cup. Funnel viscosity is reported in seconds (for a quart). Water exits the funnel in about 26 seconds. This test was one of the earliest mud measurements for field use. Simple, quick and fool-proof, it still serves as a useful indicator of change in the mud by comparing mud-in and mud-out sample funnel viscosities. <br><br> Hallan N. Marsh of Los Angeles published the design and use of his funnel viscometer in 1931, and it is worth the time to read the detailed, often humorous, discussion that followed. Mr. Marsh was a forward thinking mud technologist in his day, as can be seen from the following words from his 1931 AIME paper: <blockquote> "The subject of mud sounds so simple, uninteresting and unimportant that it has failed to receive the attention that it deserves, at least as applied to the drilling of oil wells. As a matter of fact, it is one of the most complicated, technical, important and interesting subjects in connection with rotary drilling. "</blockquote> Mr. Marsh was quoted by someone who knew him as saying (paraphrased), "Of all the things I have done in mud technology, I am remembered for inventing this d*** funnel. "<br><br>Reference:<br>Marsh H: "Properties and Treatment of Rotary Mud," Petroleum Development and Technology, Transactions of the AIME (1931): 234-251.
Industry:Oil & gas
A cone-and-plate rheometer designed to measure viscosity of non-Newtonian fluids at low shear rates and with more accuracy than is attainable with a 6-speed, direct-indicating viscometer. Such low shear-rate data are needed for designing muds with improved hole-cleaning properties and to minimize sag of weighting material. (Brookfield is a mark of Brookfield Engineering Laboratories, Inc. )
Industry:Oil & gas
A condition whereby the drillstring cannot be moved (rotated or reciprocated) along the axis of the wellbore. Differential sticking typically occurs when high-contact forces caused by low reservoir pressures, high wellbore pressures, or both, are exerted over a sufficiently large area of the drillstring. Differential sticking is, for most drilling organizations, the greatest drilling problem worldwide in terms of time and financial cost. It is important to note that the sticking force is a product of the differential pressure between the wellbore and the reservoir and the area that the differential pressure is acting upon. This means that a relatively low differential pressure (delta p) applied over a large working area can be just as effective in sticking the pipe as can a high differential pressure applied over a small area.
Industry:Oil & gas
A condition in which clays, polymers or other small charged particles become attached and form a fragile structure, a floc. In dispersed clay slurries, flocculation occurs after mechanical agitation ceases and the dispersed clay platelets spontaneously form flocs because of attractions between negative face charges and positive edge charges.
Industry:Oil & gas
A compound, CuCO<sub>3</sub>, that was used as a sulfide scavenger for water-base muds. However, it was found to be corrosive due to spontaneous plating of metallic copper onto metal surfaces, causing pitting corrosion; it has largely been replaced by zinc compounds. <br><br>Reference:<br>Perricone AC and Chesser BG: "Corrosive Aspects of Copper Carbonate in Drilling Fluids," <br>Oil & Gas Journal 68, no. 37 (September 14, 1970): 82-85.
Industry:Oil & gas
A concentrated slurry of bentonite clay mixed in fresh water. The maximum practical concentration of bentonite is about 30 to 40 lbm/bbl because greater concentrations of bentonite are difficult to mix and pump. Water is put into the rig's prehydration tank and the pH raised to 10 or 11 with caustic soda. Soda ash is added as required to remove hardness. Bentonite is slowly added through the mud hopper. Continual energetic mixing and stirring helps the clay particles fully disperse. In some muds, lignosulfonate should be added shortly before mixing the slurry into the active system to protect the colloidal clay particles from flocculation.
Industry:Oil & gas
A compound with formula CaCO<sub>3</sub> that occurs naturally as limestone. Ground and sized calcium carbonate is used to increase mud density to about 12 lbm/gal (1. 44 kg/m<sup>3</sup>), and is preferable to barite because it is acid-soluble and can be dissolved with hydrochloric acid to clean up production zones. Its primary use today is as a bridging material in drill-in, completion and workover fluids. Sized calcium carbonate particles, along with polymers, control fluid loss in brines or drill-in, completion and workover fluids. Insoluble calcium carbonate is the precipitated byproduct of mud treatments used for removal of either Ca<sup>+2</sup> or CO<sub>3</sub><sup>-2</sup> by addition of the other ion.
Industry:Oil & gas
A compound whose electrons are not shared equally in chemical bonds. A polar compound is not necessarily ionized. Water is a polar compound. Polymers can have ionizing polar groups on their complex structures.
Industry:Oil & gas
A chemical used in preparation and maintenance of an emulsion mud, which is a water mud containing dispersed oil (or a synthetic hydrocarbon). Numerous types of emulsifiers will disperse oil into water muds, including sulfonated hydrocarbons, ethyoxylated nonylphenols, alkali-metal fatty-acid soaps, lignosulfonate, lignite and lignin at high pH. Even clays, starch and carboxymethylcellulose aid emulsion mud stability. <br><br><br>Reference:<br>Rogers WF: "Oil-in-Water Emulsion Muds," in Composition and Properties of Oil Well Drilling Fluids, 3rd ed. Houston, Texas, USA: Gulf Publishing Company, 1963.
Industry:Oil & gas
A chemical that removes all three soluble sulfide species, H<sub>2</sub>S, S<sup>-2</sup> and HS<sup>-</sup>, and forms a product that is nonhazardous and noncorrosive. Zinc compounds are commonly used to precipitate ZnS and decrease the concentration of all three sulfides that are in equilibrium in a solution to a very low concentration. For water mud, zinc basic carbonate, and, for oil mud, zinc oxide, are recognized to be effective sulfide scavengers. Oxidation of sulfides to form other types of sulfur compounds will remove sulfides from a mud, but slowly and with less certainty.
Industry:Oil & gas
