- Branche: Oil & gas
- Number of terms: 8814
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A particular type of floating vessel that is supported primarily on large pontoon-like structures submerged below the sea surface. The operating decks are elevated perhaps 100 or more feet above the pontoons on large steel columns. This design has the advantage of submerging most of the area of components in contact with the sea and minimizing loading from waves and wind. Semisubmersibles can operate in a wide range of water depths, including deep water. They are usually anchored with six to twelve anchors tethered by strong chains and wire cables, which are computer controlled to maintain stationkeeping. Semisubmersibles (called semisubs or simply semis) can be used for drilling, workover operations, and production platforms, depending on the equipment with which they are equipped. When fitted with a drilling package, they may be called semisubmersible drilling rigs.
Industry:Oil & gas
A number on the scale of one to 40 according to the HLB system, introduced by Griffin (1949 and 1954). The HLB system is a semi-empirical method to predict what type of surfactant properties a molecular structure will provide. The HLB system is based on the concept that some molecules have hydrophilic groups, other molecules have lipophilic groups, and some have both. Weight percentage of each type of group on a molecule or in a mixture predicts what behavior the molecular structure will exhibit. Water-in-oil emulsifiers have a low HLB numbers, typically around 4. Solubilizing agents have high HLB numbers. Oil-in-water emulsifiers have intermediate to high HLB numbers. <br><br>Reference:<br>Griffin WC: "Classification of Surface-Active Agents by 'HLB,'" Journal of the Society of Cosmetic Chemists 1 (1949): 311. <br>Reference:<br>Griffin WC: "Calculation of HLB Values of Non-Ionic Surfactants," Journal of the Society of Cosmetic Chemists 5 (1954): 259.
Industry:Oil & gas
A particle size term referring in the strict sense (API Bulletin 13C) to any particle in the size range 44 to 74 microns. More generally it is used to indicate any particle not removed by the shaker screens.
Industry:Oil & gas
A parameter of the Bingham plastic model. PV is the slope of the shear stress/shear rate line above the yield point. PV represents the viscosity of a mud when extrapolated to infinite shear rate on the basis of the mathematics of the Bingham model. (Yield point, YP, is the other parameter of that model. ) A low PV indicates that the mud is capable of drilling rapidly because of the low viscosity of mud exiting at the bit. High PV is caused by a viscous base fluid and by excess colloidal solids. To lower PV, a reduction in solids content can be achieved by dilution of the mud.
Industry:Oil & gas
A nonionic starch derivative, analogous to hydroxyethylcellulose in its method of manufacture and most applications for drilling, workover and completion fluids. Rather than using a cellulosic starting material, such as hydroxyethylcellulose (HEC), starch is used instead, and reacted with ethylene oxide in an alkaline environment.
Industry:Oil & gas
A nonionic cellulose derivative with hydroxyethyl groups attached to the polymer structure. HEC is used as a viscosifier in brines and saline fracturing fluids, workover fluids, completion fluids and drill-in fluids. It gives pseudoplastic rheology but essentially no gel strength development. HEC offers little fluid-loss control, other than its rheological effects. HEC is seldom used in drilling fluids. Cellulose fibers are reacted with caustic soda and ethylene oxide to form HEC. Hydroxyethyl groups attach to the OH groups of the polysaccharide structure by ether linkages. A high degree of substitution (from 1. 5 to 2. 5 out of 3 maximum) gives HEC superior solubility in water and various brines. Being nonionic, it is not precipitated by hardness ions and disperses well at high salinity. HEC is not degraded by common bacteria.
Industry:Oil & gas
A neutral double salt of zinc carbonate and zinc hydroxide in 2-to-3 stoichiometric proportions, 2ZnCO<sub>3</sub>路3Zn(OH)<sub>2</sub>. Zinc basic carbonate is used as a sulfide scavenger for water-base drilling fluid in a concentration of about 0. 1 lbm/bbl per 50 mg/L GGT sulfides (determined by Garrett Gas Train sulfide analysis of the filtrate). The zinc cation reacts with the sulfide anion to form inert zinc sulfide (ZnS).
Industry:Oil & gas
A neutral to slightly alkaline salt of cesium hydroxide and formic acid having the formula HCOO<sup>-</sup>Cs<sup>+</sup>. It is extremely soluble in water. An 82 wt. % cesium formate solution has a density of 2. 4 g/cm<sup>3</sup> (19. 9 lbm/gal). It has shown favorable health, safety and environmental (HSE) characteristics in laboratory tests and has applications as a drill-in, completion or workover fluid. Cesium formate can be mixed with less expensive potassium formate to make clear brine mixtures with a density range from 1. 8 to 2. 4 g/cm<sup>3</sup>. Formates have temperature stability in the range of 375掳F (190掳C), depending on the duration of exposure to such a temperature.
Industry:Oil & gas
A new, completely inexperienced member of the drilling crew. Such a crewmember is stereotyped as prone to making mistakes and being injured, and typically endures pranks played on him by the drilling crew. While the terms weevil and its close cousin, worm, are used widely, they are labels of inexperience, rather than derogatory terms.
Industry:Oil & gas
A neutral zinc salt, ZnCO<sub>3</sub>, which can be used as a sulfide scavenger in water-base muds. Zinc carbonate is less soluble than zinc basic carbonate and perhaps slower to react with sulfide ions. Treatment level is about 0. 1 lbm/bbl per 50 mg/L sulfide ion (determined by Garrett Gas Train sulfide analysis of the filtrate).
Industry:Oil & gas
