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

A memory gauge is a self-contained downhole instrument that records pressure, temperature, or both as a function of time or depth during a wellbore operation — storing the measurements in internal solid-state… Read more →

A meniscus in petroleum engineering refers to the curved interface that forms at the boundary between two immiscible fluids (or between a fluid and a gas) within a pore throat, capillary tube, or narrow confinement,… Read more →

The mercury displacement method (also called mercury injection capillary pressure, MICP, or the Purcell method) is a laboratory technique for characterizing the pore structure of reservoir rock by injecting mercury… Read more →

Metagenesis is the final stage of the thermal maturation sequence of organic matter in source rocks, occurring at temperatures above approximately 150-200 degrees Celsius (corresponding to vitrinite reflectance values… Read more →

Metal gain in drilling operations refers to metallic particles detected in the circulating drilling fluid or cuttings returns at the shale shakers, indicating mechanical wear, erosion, or failure of downhole metal… Read more →

Metal loss in oil and gas well integrity and pipeline inspection refers to a reduction in the wall thickness of a tubular, casing string, pipeline, or pressure vessel caused by corrosion, erosion, or mechanical wear… Read more →

Metamorphic rock is any rock formed by the solid-state recrystallization, mineralogical transformation, and textural reorganization of pre-existing igneous, sedimentary, or metamorphic protoliths under elevated… Read more →

Metamorphism is the geological process by which the characteristics of rocks are altered or the rock is recrystallized in response to substantial changes in temperature, pressure, fluid composition, or other… Read more →

A device used to measure volumes or rates of fluids (liquid or gas). Read more →

The operation to adjust the meter to a specific standard. Read more →

The maximum and the minimum rate of flow specified by the manufacturer to maintain accuracy in the readings. Read more →

The difference in gas volume registered using two different meters. Read more →

A correction number for the meter. It is determined by calibrating the meter using an incompressible fluid (liquid). Read more →

The volume of liquid that is not registered by the meter at a specific flow rate. Read more →

Methane is the simplest hydrocarbon. Its chemical formula is CH4, one carbon atom bonded to four hydrogen atoms. It is a colourless, odourless gas at room temperature, lighter than air, highly flammable, and the… Read more →

Methyl orange in drilling fluid testing is a pH indicator chemical used in the alkalinity titration of drilling mud filtrate and water samples to determine the Pm (filtrate alkalinity to the methyl orange endpoint)… Read more →

Methyl orange alkalinity (Pm) is a measure of the total acid-neutralizing capacity of a drilling fluid filtrate, determined by titrating a measured volume of filtrate with standard sulfuric acid solution to the methyl… Read more →

A blue dye with a cationic charge on the molecule used as the reagent for the methylene blue test used to estimate cation-exchange capacity (CEC) of solids in a water-base drilling mud. Read more →

The MBT test (methylene blue test, also called the methylene blue capacity test or cation exchange capacity test) is a drilling fluid quality control procedure that quantifies the concentration of active clay… Read more →

A methylglucoside drilling fluid is a water-based drilling fluid system containing a high concentration of methylglucoside as a primary chemistry component — providing specialty mud chemistry that has been successfully… Read more →

Mica is a group of sheet silicate (phyllosilicate) minerals characterized by a layered crystal structure with perfect basal cleavage (splitting into thin, flexible, elastic sheets parallel to the basal plane), defined… Read more →

What Is Micellar-Polymer Flooding? Micellar-polymer flooding (also called surfactant-polymer flooding or SP flooding) is an enhanced oil recovery (EOR) process in which a surfactant-rich microemulsion slug, the micellar… Read more →

Micellar-polymer flooding is an enhanced oil recovery (EOR) technique in which a chemical solution containing surfactants organized into micelle structures (with hydrophobic tails clustered toward the interior and… Read more →

A micelle is a spherical or cylindrical self-assembled aggregate of surfactant molecules that forms spontaneously in solution when the surfactant concentration exceeds the critical micelle concentration (CMC) — in which… Read more →

Micrite is a fine-grained carbonate sediment or rock made of microscopic calcite crystals less than 4 micrometres across. The name is short for "microcrystalline calcite." Micrite forms by erosion of larger carbonate… Read more →

What Is a Microannulus? Microannulus (also called a micro-annular gap) is a very thin annular gap that forms between the outer surface of a casing string and the surrounding set cement sheath when thermal or pressure… Read more →

What Is Microbial Enhanced Oil Recovery? Microbial enhanced oil recovery (also called MEOR or microbial EOR) is an enhanced oil recovery technique that harnesses indigenous reservoir microorganisms or introduces… Read more →

The microcylindrical log (MCFL, or Micro-Cylindrically Focused Log) is a pad-mounted microresistivity wireline logging tool that measures the electrical resistivity of the very shallow formation zone immediately… Read more →

A microemulsion in oil and gas is a thermodynamically stable, optically transparent or translucent single-phase system formed spontaneously when oil, water, a surfactant, and typically a co-surfactant are combined at… Read more →

A microgel is a microscopic, partially hydrated polymer particle (commonly called a fish-eye when visible to the naked eye, though true microgels are typically invisible at 5 to 100 micrometres in diameter) that forms… Read more →