Oil and Gas Terms Beginning with “S” — Page 9

A formation in which the velocity of the compressional wave traveling through the borehole fluid is greater than the velocity of the shear wave through the surrounding formation. In such conditions, there is no critical… Read more →

A substance added at slow rate to the production fluid stream to prevent corrosion. Read more →

A parameter used to characterize neutron interactions in bulk material above the thermal region. The slowing-down length (Ls) is proportional to the root-mean-square distance from the point of emission of a high-energy… Read more →

With reference to pulsed neutron logging, the characteristic time for the decay of the epithermal neutron population. The slowing-down time of a formation is strongly dependent on the porosity. In openhole pulsed… Read more →

A technique used for identifying and measuring the slowness and time of arrival of coherentacoustic energy propagating across an array of receivers. The different packets of coherent energy can then be identified in… Read more →

A thick, viscous emulsion containing oil, water, sediment and residue that forms because of the incompatibility of certain native crude oils and strong inorganic acids used in well treatments.Use of certain additives,… Read more →

A small volume of fluid, often of a higher density than the main body of fluid, within the circulating or production-fluid system that influences the flow or production characteristics of the well. A slug may be placed… Read more →

A type of flow in which surface equipment may be damaged by the sudden impact of a liquid slug in a phenomenon called water hammer. Read more →

Accumulation of a water, oil or condensate in a gas pipeline. These fluids need to be removed using a pig. Read more →

A chemical used to break emulsions to determine the total amount of sediment and water in the samples. Read more →

(noun) The plural of slurry. Fluid mixtures containing suspended solid particles, such as cement slurries (a blend of cement powder and water used for zonal isolation), fracturing slurries (fluid carrying proppant), or… Read more →

A mixture of suspended solids and liquids. Muds in general are slurries, but are seldom called that. Cement is a slurry and is often referred to as such. Read more →

The weight per unit volume of a cementslurry, usually given in units of kg/m3 or lbm/gal. Typical oil- or gas-well slurries have densities of 1380 kg/m3 to 2280 kg/m3 [11.5 lbm/gal to 19.0 lbm/gal], although special… Read more →

The ability of a cementslurry to maintain homogeneity. Two tests are used as a measure of slurry stability: the free-fluid test and the sedimentation test. Read more →

The volume of slurry obtained when one sack of cement is mixed with the desired amount of water and other additives, usually given in units of m3/kg or ft3/sk (sack). Read more →

Water in microporosity or other small pores. The term usually refers to the nuclear magnetic resonancesignal of such water, which occurs at very short times and overlaps the signal from clay-bound water. Read more →

[(1/2Ca,Na)0.7(Al,Mg,Fe)4(Si,Al)8O20(OH)47nH2O)]A group of clay minerals that includes montmorillonite. This type of mineral tends to swell when exposed to water. Bentonite includes minerals of the smectite group. Read more →

A category of clay minerals that have a three-layer crystalline structure (one alumina and two silica layers) and that exhibit a common characteristic of hydrational swelling when exposed to with water. Montmorillonite… Read more →

A concave-upward, semicircular event in seismic data that has the appearance of a smile and can be caused by poor data migration or migration of noise. Read more →

The action of forcing a pipe or tubular into a well against wellbore pressure. Well-intervention techniques in live wells, such as coiled tubing and snubbing, use equipment designed to apply the necessary forces while… Read more →

What Is Snubbing? Snubbing is a well intervention technique that forces tubular pipe into a live, pressurized wellbore against wellbore pressure acting on the pipe cross-section, using a specialized hydraulic jack unit… Read more →

The work area at the top of a snubbing unit that houses the unit controls and a means of handling the tubulars and tool string to be run or retrieved. Read more →

The force required to insert a tool or tubing string into a live wellbore. Two main components act to determine the snubbing force: the force resulting from the wellheadpressure acting on the cross-sectional area of the… Read more →

The components of a snubbing unit that provide the vertical stroke or movement required to run or retrieve the work string. Snubbing jacks are hydraulically operated and can apply extremely high forces to the tubing… Read more →

In cyclic steam injection, the second phase between the steam-injection phase and the production phase. During the soak phase, the well is shut in for several days to allow uniform heat distribution to thin the oil. Read more →

A collective term for organic salts made by reacting an aliphatic carboxylic acid with a base. The base can be an alkali-metal hydroxide (NaOH or KOH), alkaline-earth hydroxide (Ca(OH)2 or Mg(OH)2) or oxide (CaO or… Read more →

A chemical with the formula NaHCO3. It is called bicarb at the drilling rig and is used to treat cement contamination in water mud. When cement hydrates, substantial amounts of lime, Ca(OH)2, are produced. As the cement… Read more →

A chemical with the formula Na2CO3. It is called soda ash at the drilling rig and is used to treat most types of calcium ion contamination in freshwater and seawater muds. For cement contamination, sodium bicarbonate is… Read more →

Oilfield slang term for rope not made of steel, such as nylon, cotton, or especially standard manila hemp rope. Read more →

A general term for sedimentary rocks, although it can imply a distinction between rocks of interest to the petroleum industry and rocks of interest to the mining industry. Read more →