Direct hydrocarbon detection (DHI) techniques for prospective exploration targets in Chaoshan Depression

Located in northern South China Sea, Pearl River Mouth Basin is a large Meso-Cenozoic basin. And in southeasters part of the basin lies Chaoshan Depression, which is mainly a residual Mesozoic depression, with a construction of Meso-Cenozoic strata over 7000m thick and good hydrocarbon accumulation conditions. The selected DHI technique, amplitude attribute of -90 degree phase component derived by phase decomposition is employed to the zone of interest (ZOI) of B structure, Chaoshan Depression. And it is found that there are evident amplitude anomalies occurring around ZOI of structure B. Phase decomposition is applied to forward modelling results of the ZOI, and high amplitudes occur on the -90 degree phase component more or less when ZOI is charged with hydrocarbon, which shows that the amplitude abnormality in ZOIs of structure B is probably caused by oil and gas accumulation. Meanwhile, another DHI attribute of spectral decomposition peak amplitude is applied also to ZOIs of B structure, and there is also amplitude anomalies coincides with those of -90 degree phase component. The two DHI attributes' coincidence strengthens the confidence of hydrocarbon accumulation prediction results.