Oil and Gas Terms Beginning with “I”

The inner diameter (ID) is the measurement across the internal bore of a tubular component, including casing, tubing, drill pipe, or pipeline, distinguishing it from the outer diameter (OD) and nominal pipe size (NPS),… Read more →

IEOM in oil and gas operations stands for Integrated Environmental and Operations Management, a systematic approach to managing the combined requirements of operational performance, health and safety compliance, and… Read more →

Inductive-source induced polarization. Read more →

IM (Induction Medium) in wireline logging refers to the medium-depth-of-investigation resistivity measurement from an induction logging tool — specifically the medium induction curve that investigates the formation to… Read more →

IO (injectivity index) is an abbreviation used in oil and gas well operations for the injectivity index — a measure of a well's ability to accept injected fluid, defined as the injection rate (in barrels per day)… Read more →

IP is the abbreviation for the Institute of Petroleum, the United Kingdom professional and standardization body that served the oil and gas industry for most of the twentieth century before merging into the Energy… Read more →

IPA is the standard oilfield abbreviation for isopropyl alcohol, also written as isopropanol, propan-2-ol, 2-propanol, or by its molecular formula C3H7OH (alternately written as (CH3)2CHOH), a simple secondary alcohol… Read more →

IPR (Inflow Performance Relationship) is the functional relationship between wellbore flowing pressure and the corresponding flow rate that a reservoir delivers to the wellbore, describing how much fluid the formation… Read more →

What Is IRR? IRR (Internal Rate of Return) is the discount rate at which the net present value of all cash flows from an oil and gas project equals exactly zero — representing the annualised return rate the project… Read more →

ISO (International Organization for Standardization) is the principal international standard-setting body that develops and publishes voluntary technical standards for a vast range of industries and applications —… Read more →

A remotely controlled piece of equipment that makes up or breaks down pipe using a rotary table and torque wrenches. Also called a Hydraulic Wrench. Read more →

An ideal gas (also called a perfect gas) is a theoretical model of a gas whose behavior is completely described by the ideal gas law PV = nRT, where P is absolute pressure, V is volume, n is the number of moles of gas,… Read more →

Igneous rock is rock formed by the crystallization and solidification of molten magma, classified as intrusive (plutonic) when solidification occurs at depth under confining pressure, producing coarse-grained textures… Read more →

Illite is a group of non-expanding, potassium-rich clay minerals with the general formula K1-1.5Al4(Si7-6.5Al1-1.5O20)(OH)4, formed during the alteration of silicate minerals such as mica and feldspar and abundant in… Read more →

A dense mineral whose specific gravity is 4.67 g/cm3, composed of FeO·TiO2. Ilmenite is used as a weighting agent for cement and mud. Read more →

In remote sensing, to record and interpret electromagnetic energy from the surfaces of planets or satellites using photographic displays. Read more →

An image well in pressure transient analysis is a fictitious hypothetical well introduced in the "method of images" mathematical technique to account for the effect of reservoir boundaries on pressure behavior in a real… Read more →

What Is Imbibition in Reservoir Engineering? Imbibition is the displacement process in which the wetting phase increases in saturation within a porous medium — water displacing oil in a water-wet rock, or oil displacing… Read more →

Pertaining to a hydrocarbon source rock that has not fully entered optimal conditions for generation. Read more →

Immiscible in petroleum engineering and chemistry refers to the condition in which two fluids (or a fluid and a gas at sufficient pressure) are incapable of forming a single, molecularly distributed homogeneous phase… Read more →

Acoustic impedance in seismic exploration is the product of a rock's bulk density and the compressional wave velocity through it (Z = rho x Vp), measured in units of rayl (kg/m² s) or g/cm² s — and it is the single most… Read more →

What Is an Impeller? An impeller responds to fluid movement past its blades and serves as the rotating sensing element inside a spinner flowmeter or torque flowmeter. Production engineers run impeller-based tools on… Read more →

Impermeable in petroleum geology and reservoir engineering describes a rock formation or material that has permeability too low to allow significant fluid flow under the pressure differentials encountered in subsurface… Read more →

An impermeable barrier in pressure transient analysis is a single, impenetrable barrier to fluid flow within a reservoir that causes a characteristic doubling (a factor of 2 change) in the slope of pressure buildup or… Read more →

Impressed current anodes are the electrodes used in impressed current cathodic protection (ICCP) systems to apply an external electrical current to a metal structure (such as a pipeline, offshore platform, subsea… Read more →

What Is Improved Oil Recovery? Improved oil recovery (IOR) is a broad term encompassing all methods used to increase the fraction of oil recovered from a reservoir beyond what primary drive mechanisms alone would… Read more →

What Is Impulse Activation? Impulse activation is a pulsed neutron logging mode in which a short burst of fast neutrons activates oxygen-18 in water flowing past the tool, producing nitrogen-16 (N-16) gamma ray emitters… Read more →

Seismic data whose energy source is impulsive and of short duration, as with an air gun, rather than vibratory, as with a vibrator. Read more →

In situ is a Latin term meaning in the original place or position, and in petroleum geoscience and engineering it carries two closely related senses. In its descriptive sense it refers to rock, fluid, or stress that… Read more →

In-line is a directional term that describes orientation within a three-dimensional seismic survey . An in-line is a vertical slice through the 3D data volume taken parallel to the direction in which the data were… Read more →