杭州湾地区晚第四纪浅层生物气藏勘探方法研究

The exploration method of late Quaternary shallow biogenic gas reservoirs in Hangzhou Bay area.

1. 南京大学地球科学系成矿作用国家重点实验室,江苏南京210093;2. 中国石油化工股份有限公司油田勘探开发事业部,北京100083;3. 中国石油化工股份有限公司胜利油田物探研究院,山东东营257062;4. 中国石油天然气股份有限公司浙江勘探分公司,浙江杭州310013

State Key Laboratory of Ore Deposit Research,Department of Earth Sciences,Nanjing University,Nanjing 210093,China

杭州湾地区晚第四纪地层蕴藏有丰富的天然气,气藏具有气层薄、压力低、产量小的特点,是一种非常规浅层生物气,勘探方法不能简单的采用深层气的勘探方法。通过试验研究得到以下认识:重点目标区预探或已知气田区扩边可以采用打密集静力触探井的方法;追踪砂体的形态展布和进行大面积的勘探,应配合少量的地震、电法勘探,以及静电阿尔法薄膜测量、微生物法等非地震物化探方法。静力触探井对岩性、岩相划分对比,特别是储层识别较为有效;利用浅层横波地震剖面可以圈定含气砂体的边界;EH4电磁勘探能够追踪砂体展布,推断气层的厚度;气田上方氡气和甲烷菌的含量存在明显的异常。

Late Quaternary strata of Hangzhou Bay area are abundant in nature gas. It is a kind of unconventional shallow biogenic gas and characterized by thin gas zone, low depression and low production. It is considered that drilling static sounding well densely can be used for preliminary exploration in target area or enlarging of known gas fields, The exploration to trace the shape and distribution of sand body in large-scale area should rely on some seismic, non-seismic physical and chemical methods, such as electrostatic a film measuring, microbial method, etc. Static sounding well is effective in dividing or contrasting lithology and lithofacies, especially in identifying reservoir. The boundary of gas-bearing sand body can be outlined on shallow S-wave seismic profile. EH4 electromagnetic prospecting can trace the distribution of sand body hence the thickness of gas layers is deduced. The content of radon gas and methane bacteria indicates obvious abnormity above the gas pool. By applying above methods, satisfying effects have been a-chieved during the exploration of shallow biogenic gas in late Quaternary strata of Hangzhou Bay area