Dispersion Imaged Field with No Amplitude DHI

Lack of hydrocarbon charge and permeability are risk factors for prospective hydrocarbon reservoirs. Dispersion may indicate hydrocarbon charge and permeability. Unproduced hydrocarbon reservoirs may have anomalously high relative permeability and therefore dispersion. Fluid movement in pore throats (on a particle level) indicates permeability, a cause of dispersion. Apex Spectral performed a blind dispersion processing and interpretation study for PDO. The primary goal of the study was to determine whether dispersion imaging could highlight hydrocarbon charge in Oman type reservoirs. Using only legacy seismic, dispersion intensity was computed, output in SEGY and interpreted. An 83 km2 dispersion anomaly largely positioned in a structural high was confirmed by PDO to be a known Gharif oil and gas field, where amplitude does not indicate hydrocarbons. Three Haima sandstone dispersion anomalies were imaged. One was a producing gas field; another had been tested and found hydrocarbon bearing and the third had not been tested. In addition, a dispersion anomaly related to the Khuff carbonate had been tested and found to be hydrocarbon bearing. These results show that in a blind test where amplitude was ineffective to indicate fluid type, dispersion highlighted oil and gas reservoirs in both sandstone and carbonate strata.