Oil and Gas Terms Beginning with “H” — Page 4

The outside steel case of a cartridge or a sonde in a wirelinelogging tool. The housing isolates the electronics, power supplies and sensors from the borehole and bears the pressure burden. Read more →

Slang term for a cyclic process in which a well is injected with a recovery enhancement fluid and, after a soak period, the well is put back on production. Examples are cyclic steam injection and cyclic CO2 injection. Read more →

Organic carboxylic acids of complex molecular structure (aromatic and phenolic) that comprise 10 to 90% of lignite. Humic acids in lignite react with caustic ingredients (NaOH and KOH) in mud. The water solubility of… Read more →

Moisture (water vapor) in a gaseous atmosphere, such as in air. It is quantified as relative humidity. Read more →

(noun) An instrument used to measure the moisture content or relative humidity of a gas stream, ambient air, or process environment. In gas processing and pipeline operations, humidity meters monitor water vapour levels… Read more →

The abnormal behavior in a buildup curve caused by phase redistribution in a wellbore. This behavior is most noticeable in oil wells producing a substantial amount of gas and having a substantial skin effect. Analysis… Read more →

An early scale used for the presentation of resistivity logs. The scale has two parts, equally divided about a midpoint. The left part is linear in resistivity, for example 0 on the left edge to 50 ohm-m at the… Read more →

A chemical combination of water and another substance. Gypsum is a hydrate mineral. Its anhydrous equivalent is anhydrite. Read more →

Absorption of water by a hygroscopic material such as a clay or polymer. Hydration is the first stage of clay-water (or polymer-water) interaction. When dry bentonite is stirred into water, hydration is observed as… Read more →

A design feature on packers and similar downhole tools that occupy a large proportion of the drift diameter of the wellbore. When running and retrieving such tools, the hydraulic bypass allows the wellbore fluid to flow… Read more →

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. Read more →

A type of tool-string centralizer, generally used in through-tubing applications, that employs hydraulic force to energize the centralizer arms or bows. Through-tubing operations sometimes require the tool string to be… Read more →

A technique to track the propagation of a hydraulic fracture as it advances through a formation. Microseisms are detected, located, and displayed in time for scientists and engineers to approximate the location and… Read more →

What Is Hydraulic Fracturing? Hydraulic fracturing stimulates an oil or gas reservoir by pumping fluid at pressures above the formation parting pressure, creating and propping open a network of conductive fractures in… Read more →

The force per unit area exerted by a column of liquid at a height above a depth (and pressure) of interest. Fluids flow down a hydraulic gradient, from points of higher to lower hydraulic head. The term is sometimes… Read more →

The power of a positive displacement pump. HHP is important for mud pumps and cement pumps. Read more →

A type of packer used predominantly in production applications. A hydraulic packer typically is set using hydraulic pressure applied through the tubing string rather than mechanical force applied by manipulating the… Read more →

An assembly of components and controls necessary to provide a hydraulic power supply. In modern oilfield activities, many systems are hydraulically powered, including the majority of mobile systems such as slickline… Read more →

An artificial-lift system that operates using a downhole pump. A surface hydraulic pump pressurizes crude oil called power oil, which drives the bottom pump. When a single production string is used, the power oil is… Read more →

A downhole tool designed to allow the lower and upper tool-string sections to be parted to enable retrieval of the running string. Hydraulic disconnects rely on the application of a predefined pressure through the… Read more →

A setting or operating method that uses hydraulic force applied through the tubing or running string to activate a downhole tool. In many cases a drop ball, which lands in a profiled seat, will be used to shift the… Read more →

A naturally occurring organic compound comprising hydrogen and carbon. Hydrocarbons can be as simple as methane [CH4], but many are highly complex molecules, and can occur as gases, liquids or solids. The molecules can… Read more →

What Is a Hydrocarbon Indicator? A hydrocarbon indicator (HI) , also called a direct hydrocarbon indicator (DHI), is a seismic amplitude anomaly, reflection characteristic, or attribute that can be related to the… Read more →

An area of the subsurface where source rock has reached appropriate conditions of pressure and temperature to generate hydrocarbons; also known as source kitchen, oil kitchen or gas kitchen. Read more →

An acid type commonly used in oil- and gas- well stimulation, especially in carbonate formations. The reaction characteristics of hydrochloric acid enable it to be used in a wide range of treatments, often with chemical… Read more →

An item of solids-control equipment consisting of an inverted cone, the mud being fed tangentially into the upper (larger diameter) part. The resulting spinning effect forces solids to the wall of the device and they… Read more →

A poisonous liquid acid composed of hydrogen and fluorine. Hydrofluoric acid [HF] is used primarily because it is the only common, inexpensive mineral acid that can dissolve siliceous minerals. HF is typically mixed… Read more →

(noun) A blended acid system combining hydrofluoric acid (HF) and hydrochloric acid (HCl), commonly known as mud acid, used in matrix acidising of sandstone formations to dissolve clay minerals, feldspar, and siliceous… Read more →

A type of hydrogen-induced failure produced when hydrogen atoms enter low-strength steels that have macroscopic defects, such as laminations.The defects in the steel (void spaces) provide places for hydrogen atoms to… Read more →

The process whereby steel components become less resistant to breakage and generally much weaker in tensile strength. While embrittlement has many causes, in the oil field it is usually the result of exposure to gaseous… Read more →