极值振幅和烃检技术在渤海油气勘探中的应用

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

随着渤海油田勘探节奏不断加快,寻求合适的烃检方法高效快速完成目标区油气检测对于构造勘探、岩性勘探十分重要。针对不同勘探、开发阶段的钻井资料、地质认识及油气检测需求的差异,采用不同的叠后烃检策略,对于勘探初期以构造勘探为主的渤中29构造,通过统计围区已发现油田含油气砂体的振幅值,选取合适的振幅截取门槛值,提取极值振幅和属性,达到搜索含烃概率高,油气厚度大的圈闭;统计开发阶段以岩性勘探为主的46个已钻砂体的振幅值,发现砂体的不同沉积组合和流体性质,在不同油组极值振幅截取门槛值也存在差异,针对不同油组选取与之对应的门槛值,按油组提取极值振幅和属性,得到的烃检结果与已钻井在各油组的含油气砂体吻合很好。研究成果表明极值振幅和烃检技术可以作为油田勘探、开发中一种快捷、有效搜索有利圈闭和砂体的烃检方法。

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 the hydrocarbon detection method for seeking favorable traps and sand bodies quickly and efficiently in the process of oilfield exploration and development.