- Industry: Oil & gas
- Number of terms: 8814
- Number of blossaries: 0
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A synthetic hydrocarbon liquid made by the polymerization of ethylene, H<sub>2</sub>C=CH<sub>2</sub>. LAOs and other synthetic fluids are used in synthetic-base drilling fluids and other applications in which refined oils might otherwise be used if not for HSE concerns. LAOs have a linear structure with a double bond (olefin) at the end of the chain, making them more biodegradable than other olefins. LAOs can be catalytically reacted to move the double bond toward the center of the chain length to convert them to isomerized olefins, IOs.
Industry:Oil & gas
A synthetic hydrocarbon liquid made by the polymerization of ethylene, H<sub>2</sub>C=CH<sub>2</sub>. IOs are one of several synthetic fluids that have recently been used as base for synthetic-base muds and in other applications where refined oils might otherwise be used except for HSE concerns. IOs are linear structures that have their olefin double bond in the center of the chain length. They are made by isomerization of linear alphaolefins (LAO), which have their double bond at the end of the chain. Because the olefin bond is in the central area of the chain, the physical properties of IOs are different (for example, they are generally lower viscosity) compared with the LAOs from which they are made.
Industry:Oil & gas
A surface observation of hydrocarbons, usually observed as florescent liquid on cuttings when viewed with an ultraviolet or black light (oil show) or increased gas readings from the mud logger's gas-detection equipment (gas show).
Industry:Oil & gas
A surfactant-type mud additive intended to prevent formation shales and clays from sticking to the drilling assembly and also to prevent gumbo shale from agglomerating and plugging the annulus and flowlines. Some DDs are claimed to be mud lubricants that lessen the torque and drag of the drillstring as it is rotated and moved up and down in the hole.
Industry:Oil & gas
A sudden increase in the rate of penetration during drilling. When this increase is significant (two or more times the normal speed, depending on local conditions), it may indicate a formation change, a change in the pore pressure of the formation fluids, or both. It is commonly interpreted as an indication of the bit drilling sand (high-speed drilling) rather than shale (low-speed drilling). The fast-drilling formation may or may not contain high-pressure fluids. Therefore, the driller commonly stops drilling and performs a flow check to determine if the formation is flowing. If the well is flowing, or if the results are uncertain, the driller may close the blowout preventers or circulate bottoms-up. Depending on the bit being used and the formations being drilled, a formation, even if sand, may sometimes drill slower rather than faster. This slowing of drilling progress, while technically also a drilling break, is usually referred to as a "reverse drilling break", or simply "reverse break. "
Industry:Oil & gas
A substance which, when mixed with water, hardens like stone because of a chemical reaction with the water. Hydraulic cement is capable of setting under water.
Industry:Oil & gas
A subset of the more general term "directional drilling," used where the departure of the wellbore from vertical exceeds about 80 degrees. Note that some horizontal wells are designed such that after reaching true 90-degree horizontal, the wellbore may actually start drilling upward. In such cases, the angle past 90 degrees is continued, as in 95 degrees, rather than reporting it as deviation from vertical, which would then be 85 degrees. Because a horizontal well typically penetrates a greater length of the reservoir, it can offer significant production improvement over a vertical well.
Industry:Oil & gas
A string of drillpipe or casing that consists of two or more sizes or weights. In most tapered strings, a larger diameter pipe or casing is placed at the top of the wellbore and the smaller size at the bottom. Note that since the pipe is put into the well bottom first, the smaller pipe is run into the hole first, followed by the larger diameter. Other than the different sizes, which are usually chosen to optimize well economics, there is nothing distinctive about the pipe sections. However, pipe-handling tools must be available for each pipe size, not just one size, as is the typical case.
Industry:Oil & gas
A subjective description of a filter cake, especially its toughness, slickness and hardness. A mud engineer makes these observations, which are recorded on the mud report along with filtrate volume and cake thickness. With increasing experience, the engineer's observations can become less subjective.
Industry:Oil & gas
A specific document that shows important physical and chemical characteristics of a chemical or product to alert a user, transporter or other interested party to potential safety hazards that may be associated with the material. The MSDS also contains treatments for exposure or ingestion as well as the type of equipment needed for safe handling. An MSDS is a legal requirement in most countries for all aspects of commerce involving chemicals.
Industry:Oil & gas
