Prediction of oil and gas reservoir traps by aromatic hydrocarbons from seabed sediments in Chaoshan depression,South China Sea

Abstract

In this study, an advanced geochemical exploration technology is used to predict possible oil and gas traps by detecting the content distribution of aromatic hydrocarbons in seabed sediments. Using new high-polymer adsorption materials, the trace benzene, toluene, ethylbenzene and xylene(BTEX), naphthalene, phenanthrene, anthracene(PAHs) and other aromatic components in marine surficial sediments are extracted rapidly and efficiently. On this basis, thermal desorption and gas chromatography mass spectrometry(GC-MS) are further applied to complete the qualitative and quantitative analysis of trace BTEX and PAHs in sediments. According to abnormal range of BTEX and PAHs concentrations, oil and gas traps are predicted. Based on the validation results of LW3-1 oil and gas field in Liwan area, Baiyun Depression of the deep waters on the northern slope of South China Sea as well as the two-dimensional seismic exploration results in the new Mesozoic hydrocarbon exploration areas(Chaoshan Depression), Dongsha seawaters of South China Sea, the deep waters with the depth of 1000-1500 m on the northern slope zone and central uplift belt of Chaoshan Depression are proposed to be the frontier exploration areas for Mesozoic oil and gas reservoirs. It provides an important reference for shrinking exploration target areas and reducing exploration cost.