珠江口盆地天然气水合物储层及饱和度预测

Prediction of Gas Hydrates and Free gas Using RGB Plotting and P-Impendence Inversion

天然气水合物为未来传统能源的替代能源,目前世界各国都对其展开了积极的研究。由于地下含水合物层往往伴生有游离气,而对于水合物的不同开采方式,游离气的存在可能起到正向作用或者造成生产事故,且会对环境造成污染,因此准确预测水合物分布的同时,也准确预测游离气的分布情况对水合物的安全开采意义十分重大。通常含水合物层具有明显的高纵波阻抗特征,而游离气具有低纵波阻抗特征,地震反演是最适合预测水合物和游离气的技术,但由于测井先验信息不足,造成地震反演方法预测水合物和游离气的可靠性较差。论文分别采用RGB融合、吸收分析等方法,对地震反演的结果加以验证和补充,准确预测了水合物和游离气的分布范围。

At present,lots of countries in the world have launched a positive study on gas hydrate,which is an alternative energy source of the traditional energy in the future.Along with the gas hydrate layer,there is always a free gas layer underlying it.In production of gas hydrate,the free gas may play a positive role or cause accidents,and cause pollution to the environment.Actually,the gas hydrate layer has high P-wave impedance characteristics,and the free gas has low P-wave impedance characteristics.So seismic inversion is one of the most suitable methods for prediction of gas hydrate and free gas.Due to lack of prior information on the well,poor reliability of prediction by seismic inversion may be resulted in.In this paper,we proposed an accurate prediction technology for gas hydrate and free gas,in which RGB plotting and absorption method are used to verify and supplement the results of seismic inversion,and is verified by real drilling wells.