What is DHI in seismic?

What is DHI in seismic?

A hydrocarbon indicator (HCI) or direct hydrocarbon indicator (DHI), is an anomalous seismic attribute value or pattern that could be explained by the presence of hydrocarbons in an oil or gas reservoir.

What does the flat spot indicate?

The term ‘flat spot’ refers to a badly worn section of a tyre tread. While this might not be physically visible at first, it could cause the driver to feel bumps, thumps, or vibrations while moving.

What is bright spot in seismic?

In reflection seismology, a bright spot is a local high amplitude seismic attribute anomaly that can indicate the presence of hydrocarbons and is therefore known as a direct hydrocarbon indicator. It is used by geophysicists in hydrocarbon exploration.

What is direct hydrocarbon indicators?

Seismic direct hydrocarbon indicators (DHIs) are anomalous seismic responses caused by the presence of hydrocarbons. DHIs occur when a change in pore fluids causes a change in the elastic properties of the bulk rock which is seismically detectable (i.e. there is a “fluid effect”).

What are the types of DHI?


  • 2.1 Bright spots.
  • 2.2 Dim spots.
  • 2.3 Flat spots.
  • 2.4 Phase change.
  • 2.5 Gas chimneys.
  • 2.6 Shadow effects.

What is acoustic impedance in seismic?

Acoustic impedance, the product of seismic velocity and density, is a basic physical property of rocks. Seismic traces are converted into pseudoreflection‐coefficient time series by appropriate initial processing, then into acoustic impedance by the inversion of the time series.

What causes flat tyre?

The most common cause of a flat tire is by a puncture due to a sharp object, such as nails or glass. Avoid puncture blowouts by driving around debris in the road or in parking lots whenever possible. Valve stem issues are another common cause of tire problems.

What causes flat spots when accelerating?

Engine flat spots can be linked to all sorts of issues with your car, many of which could lead to major damage to internal components if not addressed swiftly. Potential causes can include water in the fuel lines, dirty fuel injectors, faults with the engine cam belt or clogged or burnt engine valves.

What are bright spots?

Definition of bright spot informal. : a good thing that occurs during a bad or difficult time Car sales were one of the few bright spots for the economy last year.

What causes a bright spot?

Bright spots result from large changes in acoustic impedance and tuning effect, such as when a gas sand underlies a shale, but can also be caused by phenomena other than the presence of hydrocarbons, such as a change in lithology. The term is often used synonymously with hydrocarbon indicator.

What is dim spot in geophysics?

In reflection seismology, a dim spot is a local low amplitude seismic attribute anomaly that can indicate the presence of hydrocarbons and is therefore known as a direct hydrocarbon indicator.

Why is acoustic impedance important?

The acoustic impedance of an instrument for any particular fingering is one of the major factors which determines the acoustic response of the instrument in that fingering. It determines which notes can be played with that fingering, how stable they are and it also helps determine whether they are in tune.

What is a flat spot in seismology?

In reflection seismology, a flat spot is a seismic attribute anomaly that appears as a horizontal reflector cutting across the stratigraphy elsewhere present on the seismic image.

What is a flat spot in engine response?

Engine response. In automobile parlance, a flat spot occurs when the driver presses the accelerator pedal and there is a delay in the engine’s response. This fault was more common before cars had electronic fuel injection. Many engines, especially modified ones, still have flat spots in the torque curve due to resonances in the intake system,…

What is a flat spot on a railroad?

A flat spot, or wheel flat, is a fault in railroad wheel shape. A flat spot occurs when a rail vehicle’s wheelset is dragged along the rail after the wheel/axle has stopped rotating.

What does seismicity mean in geography?

Seismicity – The worldwide or local distribution of earthquakes in space and time; a general term for the number of earthquakes in a unit of time, or for relative earthquake activity. Seismograph – A device, which writes or tapes a permanent, continuous record of earth motion, a seismogram.