Application of extremal amplitude and hydrocarbon detection technique to the oil and gas exploration in the Bohai Sea

As the exploration pace of Bohai Oilfield is increased continuously, it is very important for structural and lithologic exploration to seek suitable hydrocarbon detection method so as to complete the hydrocarbon detection of the target area efficiently and quickly.Considering the differences of drilling data, geological understanding and hydrocarbon detection demand in different stages of exploration or development, different hydrocarbon detection strategies are adopted.In Bohai 29 structure where structural exploration is dominant in the early stage, the suitable amplitude interception threshold is selected and extremal amplitude and attribute are extracted by conducting statistical analysis on the amplitudes of the oil/gas bearing sand bodies in the discovered oilfields in the surrounding area, so as to search for the traps with high hydrocarbon bearing probability and large hydrocarbon thickness.As for 46 drilled sand bodies where lithologic exploration is dominant in the development stage, their amplitudes are reviewed.It is discovered that in different oil formations, different depositional combinations and fluid properties of sand bodies are also different in the extremal amplitude interception threshold.Therefore, the threshold is selected corresponding to different oil formations, and extremal amplitude and attribute are extracted based on each oil formation.The hydrocarbon detection result is accordant with the oil/gas bearing sand bodies of each oil formation in drilled wells.In conclusion, the extremal amplitude and the hydrocarbon detection technique can be used as thehydrocarbon detection method for seeking favorable traps and sand bodies quickly and efficiently in the process of oilfield exploration and development.