辽东湾太古界地层裸眼完井可行性力学分析

辽东湾太古界潜山变质岩地层中油气蕴藏丰富,开发中储层段水平井拟采用裸眼完井。但如果储层强度过低,裸眼段在生产过程中可能发生井壁坍塌,造成复杂事故。根据太古界变质岩地层岩心力学实验结果,建立了测井数据分析变质岩地层强度的模型,对太古界地层强度随垂深的变化进行计算,并利用裸眼完井井壁稳定分析方法计算稳定井壁所需的最低井底流压,得出生产中允许的最大生产压差。计算结果表明,受风化壳影响太古界变质岩地层存在低强度带,在下套管封固住上部低强度地层后,采用裸眼完井是可行的,但实际生产压差不能高于计算得到的极限生产压差。

Mechanical Analysis of Open Hole Completion Feasibility of Archaeozoic in Liaodong Bay

There are abundant oil and gas in Archaeozoic metamorphic rocks of Liaodong Bay. Horizontal wells and open hole completion are designed as development mode. If the strength of reservior is too low, borehole collapse will occur during the production process in open hole, making complex trouble. An analysis model was built to predict compress strength with log data and calculate the strength changes with vertical depth base on mechanical experiment results of metamorphic rocks cores. Then the minimum bottom hole flowing pressure that maintain borehole stability was calculated using the analysis method of open hole wellbore stability, through which the allowable maximum production pressure difference could be get. Calculation results show that there are low strength zones in Archaeozoic metamorphic rock formation because of weathering crust. Open hole completion is feasible if the upper low strength zones are cemented, but the actual production pressure difference cannot be higher than the calculated limit production pressure difference.