致密油水平井地质导向技术及其应用

Geosteering Technology of Horizontal Well for Tight Oil and Its Application

致密油藏储层厚度小,储层多变存在不确定性,因而近钻头地质导向系统在致密油水平井中有着很高需求。在接近钻头处通过电阻率、方位伽马等数据,将几何导向转变为地质导向,实时引导钻头在储层中钻进。以地质导向为主的钻井过程主要分为钻前建模、轨迹优化、水平段地质导向钻井、钻后评价。随钻测井的实际意义在于利用方位伽马确定钻进、钻出油气层,利用上下伽马计算地层视倾角,利用伽马成像资料计算地层真倾角,利用电阻率确定层界面,有利于识别薄层。该系统在樊××井的应用取得了良好效果,实现了91.7%的钻遇率。采用地质导向钻井技术可有效识别储层,实时优化钻井轨迹,指导水平井井眼轨迹在优质储层中穿行,提高钻井效率。

The demands of near-bit geosteering system is higher for the horizontal wells in tight oil because of thin and uncertain reservoirs in the tight oil reservoirs.Geometric steering may be turned into geosteering according to resistivity,azimuth gamma and other data near bit,and the bit may be guided to drill in the reservoirs.The geosteering-centered drilling process may be divided into pre-drilling modeling,trajectory optimization,geosteering drilling at horizontal section and post-drilling evaluation.The actual significance of logging while drilling is to determine the time of drilling in and out according to the azimuth gamma,to calculate apparent dip according to gamma,to calculate true dip according to gamma imaging information,and to fix layering interface according to the resistivity,which is favorable for identifying thin layers.The geosteering system has obtained good effect in certain Well Fan,and drilling ratio is 91.7%.The geosteering drilling technology can effectively identify the reservoir,optimize drilling trajectory on time,guide horizontal well track in the high quality reservoirs,and improve drilling efficiency.