Oil and Gas Terms Beginning with “H” — Page 3

A type of viscometer generally used in laboratories to test drilling fluids at simulated downhole conditions. Read more →

A perforating gun having more than four shots per foot. In addition to providing a greater number of perforations, a high-shot density gun also improves the phasing, or distribution of perforations, around the wellbore. Read more →

A systems tract bounded below by a downlap surface and above by a sequence boundary, commonly abbreviated as HST. This systems tract is characterized by an aggradational to progradational parasequence set. Read more →

The act of adjusting a model of a reservoir until it closely reproduces the past behavior of a reservoir. The historical production and pressures are matched as closely as possible. The accuracy of the history matching… Read more →

A crossplot of two components of particle motion over a time window. Hodograms are used in boreholeseismology to determine arrival directions of waves and to detect shear-wave splitting. Data recorded along two geophone… Read more →

With reference to multiphase flow in pipes, the fraction of a particular fluid present in an interval of pipe. In multiphase flow, each fluid moves at a different speed due to different gravitational forces and other… Read more →

The point or depth at which a tool or drift of a specific size can no longer pass through the wellbore. A higher than expected holdup depth may result from scale, fill, distortion of the wellbore tubulars or formation… Read more →

A two-dimensional display, using colors or different grey scales, of the holdup around the borehole versus depth. The x-axis of the image shows different segments of the borehole, normally inside a casing, displayed… Read more →

A record of the fractions of different fluids present at different depths in the borehole. Various techniques are used to measure these fractions. The earliest techniques measured the fluid density, using a… Read more →

(noun) A graphical representation showing the distribution of fluid phases (oil, water, and gas) as fractions of the total flow area or volume at various depths or locations in a wellbore or pipeline, derived from… Read more →

A device for determining the water holdup in a producing well by measuring the capacitance or impedance of the fluid. The holdup meter is used to produce a capacitance log. Since water has a high dielectric constant,… Read more →

The quality of uniformity of a material. If irregularities are distributed evenly in a mixture of material, the material is homogeneous. (Compare with isotropy.) Read more →

Formation with rock properties that do not change with location in the reservoir. This ideal never actually occurs, but many formations are close enough to this situation that they can be considered homogeneous. Most of… Read more →

The high-capacity J-shaped equipment used to hang various other equipment, particularly the swivel and kelly, the elevator bails or topdrive units. The hook is attached to the bottom of the traveling block and provides… Read more →

The total force pulling down on the hook. This total force includes the weight of the drillstring in air, the drill collars and any ancillary equipment, reduced by any force that tends to reduce that weight. Some forces… Read more →

A type of packer than utilizes an assembly of friction blocks and slips to set and anchor the packer on the casing or liner wall. Hookwall packers generally are run on tubing or drillpipe and typically require some… Read more →

The device used to facilitate the addition of drilling fluid additives to the whole mud system. While several types of hoppers exist, they generally have a high velocity stream of mud going through them and a means of… Read more →

An interface that might be represented by a seismic reflection, such as the contact between two bodies of rock having different seismic velocity, density, porosity, fluid content or all of those. Read more →

A map view of a particular reflection in a 3D seismic survey, as opposed to a horizontal (depth) slice or at a given time (a time slice). Slices are convenient displays for visual inspection of seismic attributes,… Read more →

What Is Horizontal Drilling? Horizontal drilling deflects a wellbore from vertical to a near-horizontal trajectory inside the target formation, exposing thousands of meters of reservoir rock to the production string.… Read more →

The resistivity of a formation measured by flowing current in a horizontal plane. In anisotropic formations the horizontal and vertical resistivities are different. In a vertical well, wirelineinduction logs and… Read more →

A vessel, with its cylindrical axes parallel to the ground, that is used to separate oil, gas and water from the produced stream. The horizontal separator can be a two-phase or three-phase separator. Read more →

A method to convey or reserve oil, gas or mineral rights at specific depths or geologic horizons. Read more →

A Christmas tree design for subsea applications, configured with the master valves and flow-control equipment on a horizontal axis to minimize the assembly height. Read more →

A relatively high-standing area formed by the movement of normal faults that dip away from each other. Horsts occur between low-standing fault blocks called graben. Horsts can form in areas of rifting or extension,… Read more →

A particularly difficult set of well conditions that may detrimentally affect steel, elastomers, mud additives, electronics, or tools and tool components. Such conditions typically include excessive temperatures, the… Read more →

A truck- or skid-mounted unit used to heat oil or treatment fluid. Hot oilers are routinely used in the removal of wax deposits from the upper wellbore section of wells in cold climates where low wellhead temperatures… Read more →

Circulation of heated fluid, typically oil, to dissolve or dislodge paraffin deposits from the production tubing. Such deposits tend to occur where a large variation in temperature exists across the producing system. Read more →

The process of drilling a hole through a pressure barrier using special equipment and procedures to ensure that the pressure and fluids are safely contained when access is made. Hot tapping is often used to enable… Read more →

A method of thermal recovery in which hot water is injected into a reservoir through specially distributed injection wells. Hot waterflooding reduces the viscosity of the crude oil, allowing it to move more easily… Read more →