- Industry: Oil & gas
- Number of terms: 8814
- Number of blossaries: 0
- Company Profile:
Mud that is left somewhere in the wellbore when some other fluid is pumped into the well. This can occur when pumping an oil mud into a well to displace a water mud. The bypassed water mud becomes a contaminant in the oil mud when it gets mixed into the circulating system. Drilling mud may be bypassed behind a casing or a liner when pumping cement into the casing or wellbore annular region. This mud-contaminated cement might not set up and might not isolate zones satisfactorily.
Industry:Oil & gas
Moisture (water vapor) in a gaseous atmosphere, such as in air. It is quantified as relative humidity.
Industry:Oil & gas
Mud that comes back to the surface and exits through the flowline after being pumped down the drillpipe. "Lost returns" is the situation in which some or all of the mud does not come back to the surface, which indicates that mud is being lost into weak, fractured or vugular formations downhole.
Industry:Oil & gas
Mathematical relationship between the densities and the corresponding volumes of mixtures of liquid-solid slurries and clear fluid blends, such as drilling muds and completion fluids. Assumptions are: (1) masses and volumes of components are additive and (2) material is neither generated nor lost from the system. As a simple example, below are the two material-balance equations for a three-component mixture of oil (o), water (w) and solids (s), where V = volume percent, D = specific density and MW = mixture weight. (This could represent a simple, weighted oil-base mud formulation. )<p>MW = DsVs + DoVo + DwVw<br>100% = Vs + Vo + Vw. </p>By solving these equations simultaneously, an unknown parameter can be found if other parameters are known or can be estimated accurately. Material-balance equations are used to derive formulations of muds, to calculate the amount of barite needed to weight-up a mud, to determine the amount of water needed to dilute a mud, and to find the volume of two or more muds to mix together to achieve a new mud weight and volume. Material balance is also the basis for calculating solids content of muds based on mud testing data.
Industry:Oil & gas
Materials, especially rock masses, that formed in their present location and have not been transported. Fault surfaces can separate indigenous rocks from allochthonous rocks, although some allochthonous rocks are clearly delineated by their differing composition.
Industry:Oil & gas
Linear, anionic polymer made from the monomer acrylic acid, CH<sub>2</sub>=CHCOO<sup>-</sup> H<sup>+</sup>. The acrylic acid groups are evenly spaced along the chain. Acrylic acid polymer neutralized with NaOH is sodium polyacrylate (SPA). Polyacrylates are best utilized in soft water with low salinity to achieve the best dispersion and full chain elongation. Even low concentrations of hardness ions, for example, Ca<sup>+2</sup>, precipitate polyacrylates. Low molecular-weight polyacrylates are used as clay deflocculants. High molecular weight polymers are used for fluid-loss control and as a clay extender. As an extender, SPA is added to bentonite at the grinding plant. It is also used at the rig in low-solids mud. Divalent cations can negate its benefits as a clay extender. SPA is highly efficient when used to flocculate colloids in native-solids muds, clear-water muds and wastewater cleanup. The polymer chain links together colloidal solids that can be removed by gravity settling in shallow pits or by applying hydrocyclone, centrifuge or filtration techniques.
Industry:Oil & gas
Large-diameter pipe lowered into an openhole and cemented in place. The well designer must design casing to withstand a variety of forces, such as collapse, burst, and tensile failure, as well as chemically aggressive brines. Most casing joints are fabricated with male threads on each end, and short-length casing couplings with female threads are used to join the individual joints of casing together, or joints of casing may be fabricated with male threads on one end and female threads on the other. Casing is run to protect fresh water formations, isolate a zone of lost returns or isolate formations with significantly different pressure gradients. The operation during which the casing is put into the wellbore is commonly called "running pipe. " Casing is usually manufactured from plain carbon steel that is heat-treated to varying strengths, but may be specially fabricated of stainless steel, aluminum, titanium, fiberglass and other materials.
Industry:Oil & gas
Large capacity self-locking wrenches used to grip drillstring components and apply torque. The breakout tongs are the active tongs during breakout operations. A similar set of tongs is tied off to a deadline anchor during breakout operations to provide backup to the connection, not unlike the way a plumber uses two pipe wrenches in an opposing manner to tighten or loosen water pipes, except that breakout tongs are much larger.
Industry:Oil & gas
Large-capacity, self-locking wrenches used to grip drillstring components and apply torque. As with opposing pipe wrenches for a plumber, the tongs must be used in opposing pairs. As a matter of efficiency, one set of tongs is essentially tied off with a cable or chain to the derrick, and the other is actively pulled with mechanical catheads. The breakout tongs are the active tongs during breakout (or loosening) operations. The makeup tongs are active during makeup (or tightening) operations.
Industry:Oil & gas
Jargon referring to the two gel-strength values for a mud. The 10-second and 10-minute "gels," often written as one number over the other. For example, 6/16 means 6 lb/100 ft<sup>2</sup> and is 10-second gel, and 16 lb/100 ft<sup>2</sup> is the 10-minute gel.
Industry:Oil & gas
