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

The high-pressure, high-temperature (HPHT) filtration test in drilling fluid engineering is a standardized laboratory procedure that measures the fluid loss (filtrate volume) and filter cake properties of a drilling mud… Read more →

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

A high-shot density gun, almost universally abbreviated HSD, is a perforating gun that fires more than four shaped charges per linear foot of carrier, with modern Western Canadian Sedimentary Basin completions commonly… Read more →

A highstand systems tract, abbreviated HST, is the package of sediment deposited during the late stage of a relative sea-level rise and the early stage of the following stillstand, when the rate of base-level rise has… Read more →

What Is History Matching? History matching (also called reservoir model calibration ) is the process of adjusting a reservoir simulation model's input parameters — permeability, porosity, relative permeability curves,… Read more →

A hodogram is a graphical representation of the trajectory of particle motion in a seismic wave over a selected time window, constructed by plotting one component of ground motion (velocity or acceleration) on the… Read more →

Holdup in production logging is the fraction of the wellbore cross-sectional area occupied by a specific fluid phase (water holdup Hw, oil holdup Ho, or gas holdup Hg) at any given depth in a multiphase flowing system,… Read more →

Holdup depth (abbreviated HUD) is the measured depth in a wellbore at which a tool, drift mandrel, or gauge of a specified outside diameter can no longer pass freely through the casing, tubing, or open hole due to the… Read more →

A holdup image is a production logging measurement that provides a spatial cross-sectional or azimuthal display of the local phase fractions (holdup) of oil, water, and gas within a flowing wellbore at a specific depth,… Read more →

A holdup log is a production logging measurement that determines the fraction of a wellbore's cross-sectional area occupied by each flowing phase — oil, water, and gas — at discrete depth intervals, enabling the… 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 holdup meter is a production logging tool that determines the water holdup (the volumetric fraction of water in a flowing multiphase fluid mixture in a producing wellbore) by measuring the electrical capacitance or… Read more →

Homogeneity is the quality of uniformity in a material, the condition in which a property is the same at every location within the body being described. In reservoir geology and petrophysics, a rock is called… Read more →

A homogeneous formation in petroleum engineering and formation evaluation is a subsurface rock unit that exhibits uniform properties (permeability, porosity, mineralogy, grain size, and fluid content) throughout its… Read more →

The hook is a large, heavy steel load-bearing device on a drilling rig that hangs from the traveling block and supports the entire suspended weight of the drill string, casing string, or other equipment during drilling,… Read more →

What Is Hook Load? Hook load (also called hook weight ) is the total downward force measured at the traveling block hook that supports the drill string, casing string, or other tubulars suspended in the wellbore. It is… Read more →

A hookwall packer is a mechanical packer designed to be set in open hole (uncased wellbore) by anchoring to the borehole wall through hook-shaped slips or drag blocks that engage the formation rock rather than biting… Read more →

A hopper (also called a mud hopper, jet hopper, or venturi hopper) is a mechanical device used on drilling rigs to mix dry bulk materials — bentonite, barite, polymers, cement, and other powdered or granular additives —… Read more →

A horizon, in oil and gas geoscience, is a surface or interface within the subsurface that can be traced laterally because it marks a meaningful change in rock properties. In its most common usage the term means a… Read more →

What Is a Horizon Slice? A horizon slice is a map view of seismic data extracted along a picked reflector in a 3D seismic volume. AAPG interpretation guidance distinguishes horizon slices from flat time slices because a… 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 →

Horizontal resistivity (Rh) is the resistivity of a formation measured by current flowing in a horizontal plane (perpendicular to the formation's bedding planes in horizontally bedded formations) — distinguished from… Read more →

What Is a Horizontal Separator? A horizontal separator (also called a horizontal production separator or horizontal pressure vessel ) is a cylindrical pressure vessel oriented with its long axis horizontal, designed to… Read more →

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

A horizontal tree is a subsea Christmas tree in which the master and flow-control valves are arranged on a horizontal axis off the side of the tree body rather than stacked vertically over the wellbore, and in which the… Read more →

A horst is a relatively elevated crustal block bounded on two or more sides by normal faults that dip away from the block (antithetic fault geometry), producing a structurally high feature surrounded by downthrown… Read more →

Hostile environment in oil and gas operations refers to wellbore or surface conditions that are sufficiently extreme in temperature, pressure, chemical corrosivity, mechanical stress, or a combination of these factors… Read more →

A hot oiler (also called a hot oil unit or hot oil truck) is a truck-mounted or skid-mounted oilfield service unit equipped with a high-pressure pump, a heating system (typically a direct-fired heat exchanger using… Read more →

Hot oiling is a well-servicing treatment in which heated crude oil, condensate, or refined hydrocarbon is pumped down the wellbore (typically down the casing-tubing annulus and back up the production tubing) at… Read more →

Hot tapping is the process of drilling, cutting, or puncturing a hole through a pressure-containing barrier (a pipeline wall, a vessel shell, a wellhead component, or a pressurized process line) while the system remains… Read more →