DHIs

DHI's

image

Deric Cameron

Author
Nov 21, 2023
|
Deric Cameron

A seismic attribute known as the Direct Hydrocarbon Indicator (DHI) serves as an indicator for the potential existence of hydrocarbons (oil and gas) directly within seismic data. This attribute operates on the principle that the presence of hydrocarbons can induce specific seismic responses distinct from those caused by water or other non-hydrocarbon substances. DHIs prove valuable in pinpointing potential hydrocarbon reservoirs, assessing exploration opportunities, and mitigating drilling risks.

Within seismic data, Direct Hydrocarbon Indicators (DHIs) manifest as features suggesting the presence of hydrocarbons (oil and gas) beneath the Earth's surface. The analysis and interpretation of seismic data, acquired through seismic surveys designed to image the subsurface and locate possible hydrocarbon reservoirs, involve the processing of these indicators. DHIs are instrumental in the identification and characterization of these reservoirs.

  1. Bright Spots --> Explanation: Bright spots are areas of high amplitude on seismic data that may indicate the presence of hydrocarbons. Processing Significance: Seismic processors analyze these bright spots for potential reservoirs.
  2. Flat Spots --> Explanation: A flat reflection (constant amplitude) is often associated with hydrocarbon-filled reservoirs. Processing Significance: Flat spots can be indicative of fluid-filled reservoirs, suggesting the presence of hydrocarbons. I will try to expand on this in a smaller future post.
  3. Dim-Out Zones --> Explanation: Dim-out zones occur when the seismic signal is attenuated due to the presence of hydrocarbons. Processing Significance: Identifying dim-out zones can help pinpoint areas where hydrocarbons may be present.

Seismic DHIs are interpreted and analyzed in conjunction with other geological and geophysical data to evaluate the potential for hydrocarbon accumulation. They can help geoscientists prioritize drilling locations, identify drilling targets, and make informed decisions during the exploration and development of oil and gas reservoirs. However, it is important to note that DHIs are not conclusive evidence of hydrocarbons and need to be further validated through additional data and analysis, such as well data, geological studies, and geophysical investigations.