Tuesday, September 8, 2015

Drilling fluid glossary H

Hardness (water). The hardness of water is due principally to calcium and magnesium ions. The total hardness is measured in terms of parts per million of calcium carbonate or calcium and sometimes epm of calcium. See: API RP 13B.
Head. The height a column of fluid would stand in an open-ended pipe if it was attached to the point of interest. The head at the bottom of a 1000-ft well is 1000 ft, but the pressure would be dependent on the density of the drilling fluid in the well.
Heaving. The partial or complete collapse of the walls of a hole resulting from internal pressures due primarily to swelling from hydration or formation pressures or from internal stresses. See: sloughing.
Heavy solids. See: high-gravity solids.
Hertz. A unit of frequency: cycles per second.
Heterogeneous. A substance that consists of more than one phase and is not uniform, such as colloids, emulsions, etc. It has different properties in different parts.
High-gravity solids (HGS). Solids purchased and added to a drilling fluid specifically and solely to increase drilling-fluid density. Barite (4.2 specific gravity) and hematite (5.05 specific gravity) are the most common additives used for this purpose. See: low-gravity solids.
High-pH drilling fluid. A drilling fluid with a pH range above 10.5. A high-alkalinity drilling fluid. See: pH.
High-yield clay. A classification given to a group of commercial drilling clay preparations having yield of 35 to 50 bbl/ton, an intermediate rating between bentonite and low-yield clays. High-yield drilling clays are usually prepared by peptizing low-yield calcium montmorillonite clays or, in a few cases, by blending some bentonite with the peptized low-yield clay. See: low-yield clay, bentonite.
HLB. Hydrophilic-lipophilic balance. See: hydrophilic-lipophilic balance.
Homogeneous. Of uniform or similar nature throughout, or a substance or fluid that has at all points the same property or composition.
Hook strips. The hooks on the edges of a screen section of a shale shaker that accept the tension member for screen mounting.
Hook-strip panel. One of the two main screen panel types, which consists of one to three layers of screen bordered by metal strips running parallel to the loom. The metal strips have a U-shaped cross section that allows them to be secured and stretched by the shaker tensioning drawbars. These screens are nonpretensioned. See: Rigid frame panel.
Hopper. A large funnel-shaped or cone-shaped device for mixing dry solids or liquids into a drilling-fluid stream in order to uniformly mix these materials into the slurry. The solids are wetted prior to entry into the drilling-fluid system. The system usually consists of a jet nozzle, an open top hopper, and a downstream venturi. See: mud hopper.
Horsepower. The rate of doing work or of expending mechanical energy; that is, horsepower is work performed per unit of time.
1 hp= 550 ft-lb per sec= 0:7067 Btu per sec:
= 0:7457 kilowatt (rated horsepower, converted to kilowatts
= horsepower x 0:746= kilowatts)
Motor nameplate horsepower is the maximum steady load that the motor can pull without damage.
Horsepower-hour. Horsepower-hour (hp-hr) and kilowatt-hour (kW-hr) are units of work.
1 hp-hr= 1,980,000 ft-lb= 2545 Btu
1 hp-hr= 0.7457 kW-hr
1 kW-hr= 1.341 hp-hr= 3413 Btu= 2,655,000 ft-lb
Horseshoe effect. The U shape formed by the leading edge of drilling fluid moving down a shale shaker screen. The drilling fluid usually tends to pass through the center of a crowned screen faster than it passes through the edges, creating the U shape.
HTHP. High temperature high pressure.
HTHP filter press. A device used to measure the fluid loss under HTHP conditions. See: HTHP fluid loss.
HTHP fluid loss. The fluid loss measured under HTHP conditions, usually 300 Fahrenheit and 500 psi differential pressure. See: HTHP filter press.
Humic acid. Organic acids of indefinite composition found in naturally occurring leonardite lignite. The humic acids are the active constituents that assist in the positive adjustment of drilling-fluid properties. See: lignin.
Hydrate. A substance containing water combined in molecular form (such as CaSO4 .2H2O). A crystalline substance containing water of crystallization.
Hydration. The act of a substance to take up water by means of absorption and/or adsorption; usually results in swelling, dispersion and disintegration into colloidal particles. See: absorb, absorption, adsorb, adsorbed liquid.
Hydroclone. See: cyclone, hydrocyclone.
Hydrocyclone. Aliquid/solids separation device utilizing centrifugal force for settling. Fluid tangentially and spins inside the cone. The heavier solids settle to the walls of the cone and move downward until they are discharged at the cone bottom (cone apex). The spinning fluid travels partway down the cone and back up to exit out the top of the cone through the vortex finder.
Hydrocyclone balance point. (1) That adjustment of the apex that creates an opening about the same diameter as the air cylinder inside of the hydrocyclone. (2) In the field, to adjust a balanced design hydrocyclone during the setup of the solids-control system so that it discharges only a slight drip of water at the underflow opening.
Hydrocyclone size. The maximum inside working diameter of the cone part of a hydrocyclone.
Hydrocyclone underflow. The discharge stream from a hydroclone that contains a higher percentage of solids than does the feed. See: solids discharge.
Hydrogen ion concentration. A measure of either the acidity or alkalinity of a solution, normally expressed as pH. See: pH.
Hydrolysis. Hydrolysis is the reaction of a salt with water to form an acid or base. For example, soda ash (Na2CO3) hydrolyzes basically, and hydrolysis is responsible for the increase in the pH of water when soda ash is added.
Hydrometer. A floating instrument for determining the specific gravity or density of liquids, solutions, and slurries.
Hydrophile. Any substance, usually in the colloidal state or an emulsion, that is wetted by water; that is, it attracts water or water adheres to it. See: lipophile.
Hydrophilic. A property of a substance having an affinity for water or one that is wetted by water. See: lipophilic.
Hydrophilic lipophilic balance. The relative attraction of an emulsifier for water and for oil. It is determined largely by the chemical composition and ionization characteristics of a given emulsifier. The HLB of an emulsifier is not directly related to its solubility, but it determines the type of an emulsion that tends to be formed. It is an indication of the behavioral characteristics and not an indication of emulsifier efficiency.
Hydrophobe. Any substance, usually in the colloidal state, that is not wetted by water.
Hydrophobic. Any substance, usually in the colloidal state or an emulsion, that is not wetted by water; that is, it repels water or water does not adheres to it.
Hydrostatic pressure head. The pressure exerted by a column of fluid, usually expressed in pounds per square inch. To determine the hydrostatic head in psi at a given depth, multiply the depth in feet by the density in pounds per gallon by the conversion factor, 0.052.
Hydroxide. Designation that is given basic compounds containing the OH– radical. When these substances are dissolved in water, the pH of the solution is increased. See: base, pH.
Hygroscopic. The property of a substance enabling it to absorb water from the air.

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