【摘要】 针对南海北部深水区钻井数量少、钻遇层位浅和高质量地层速度难以获取三大突出问题,从地层压力计算模型改进和地层速度提取两个关键环节入手,首先改进趋势地层压力计算模型,提出压缩因子概念,提高地层压力计算精度;然后利用速度谱资料获取低频速度,并通过有色反演提取地震相对速度,将低频速度与相对速度合成为高质量的地震绝对速度,最终形成一套适用于南海北部深水区白云凹陷的高精度地层压力钻前地震预测方法。应用新计算模型和地震绝对速度对白云凹陷进行地层压力钻前地震预测,经实测资料验证,新方法预测精度较高,预测结果表明白云凹陷珠海组和珠江组以静水压力为主,古近系发育超压,超压体系可为深层油气向上运移提供强劲动力。更多还原

【Abstract】 Deepwater area of northern South China Sea is featured by sparse well controls,shallow depth of drilling and difficulty of getting precise formation velocity.Considering the unique conditions in this area,this paper first improves models for pressure computation and extracts formation velocity,then discusses how to build precise computation models and how to obtain high-quality seismic absolute velocity,finally presents a method on predrill prediction of formation pressure using seismic data.A tendency prediction model for formation pressure has been improved through compressibility factor,a low frequency velocity model has been set up,and a relative velocity has been extracted by means of color inversion.Then seismic absolute velocity is acquired by compounding these two velocities.Ultimately,with the new calculation model and high-quality seismic absolute velocity,predrill prediction of formation pressure has been conducted at Baiyun depression.Testified by measured pressure,the predicted results turn out to be with high-precision.Our study shows that hydrostatic pressure develops in Zhuhai Formation and Zhujiang Formation,high amplitude overpressure develops in Paleogene at Baiyun Depression.Overpressure system would provide strong power for hydrocarbon upward migration.更多还原