The Geological Conditions Of Gas Hydrate On The Edge Of And Adjacent To Qiongdongnan Basin

Gas hydrate is a kind of clean and efficient energy sources. Developing gas hydrate will improve the energy supply situation of our society by the roots. And it is also of great economic significance to deal with environmental pollution as well as prevent marine geological disaster. In this paper, CNPC mineral rights area in Qiongdongnan basin and Zhongjiannan basin is the main research object. A lot of methods were carried out to analyze of the favorable conditions of gas hydrate in the work area, such as the regional structural geology, sedimentary basin development and dynamic conditions, submarine heat flow parameters, deposition rate, sediment grain size, sediment thickness, abnormal of geochemical indicators in the sediment, seawater samples and so on. Based on the above works, we selected four seismic profiles. Try to use the elastic bottom parameters to identify gas hydrate. Demonstrate geological conditions on the control of gas hydrate formation, and select the favorable block of gas hydrate in CNPC mineral rights area.Through the data research we found that, the northwestern shelf of the South China Sea (CNPC mineral rights area) has good conditions for gas hydrate reservoirs and exploration prospects. Firstly, since Mesozoic the region had adequate terrigenous supply and high level of marine productivity, where can produce sufficient gas. Secondly, sediment has good porosity and permeability properties. Thirdly, the seabed lower temperature geothermal gradient is low, enabling the formation of thick gas hydrate rich save and the collective. On this basis, we selected the following seismic profile to explain the geological conditions on the control of gas hydrate formation:cutting the fault beam, cutting sediment thickness line and across the complex landscape region.The seismic data interpretation and regional geological analysis are displayed thick sediment, clear stratum, rich of the faults in bottom, and good conditions for gas hydrate reservoirs in northwest CNPC mineral rights area (south-eastern Qiongdongnan basin). The most important accumulation model of gas hydrate in the region structural Slope type is fault - stratum type. The faults in the basin offer channels for petrolic gas reservoir to Spread. Gas source is pyrolysis methane gas with characteristics of mature gas or coal gas.The continental margin slope which is in West and south-west of Qiongdongnan basin and many structural features such as faults provided favorable conditions for migration and reposition of gas hydrate. In the south of CNPC mineral rights area (close to Zhongjiannan basin), the obvious signs of gas hydrate reservoir was not found.