巴什托构造井身结构优化设计研究

The Study of Casing Program Optimization for Wells in Ba Shituo Structure

巴什托构造是巴麦地区主要勘探区块之一。该构造工程地质条件复杂,多套压力系统并存,前期探井多采用的四层次井身结构设计方案,在实施过程中常有涌、卡等井下复杂情况的发生,明显减缓了钻井速度,增加了钻井成本。在已钻探井的基础上,通过对邻井地层岩性、测井和实钻资料进行统计分析,以BX井为例,对此构造的地层岩石力学参数进行了分析研究。优选地层压力预测方法并建立了其地层压力剖面和安全钻井液密度窗口,结合地层岩性条件综合提出了改进后的五层次井身结构设计方案,并进行了优选和对比分析。通过实钻资料对比,改进后的井身结构更为合理,能够避免下部井段易卡的复杂情况的发生。后续施工的三口井均采用了优化后的井身结构设计方案,取得了良好的效果,减少了井下复杂事故的发生,节约了钻井成本,提高了钻速。

Ba Shituo structure is the key exploration block of Ba Mai district. The formation lithology and pres- sure system are complicated in this structure. The four layers casing program used in wells before could not satisfied the drilling requirement, kicking and sticking were encountered often during drilling. It decreased the ROP and in- creased drilling cost. Taking well BX as an example, the formation mechanical perameters is analyzed, then the formation pressure profile and safety mud window profile are established according to the analysis of the formation li- thology, logging and in-situ drilling data of the offset. At last the optimum casing program has been provided. Com- pared with the program before, the new one could avoid problems such as kicking and sticking during drilling very well by the in-situ drilling data analysis, another three wells in this structure drilled later with the new casing pro- gram proved that the new program could reduce the drilling problems, increase ROP and lower the cost of drilling engineering.