疏松砂岩储层水平井安全钻井周期数值模拟计算

NUMERICAL SIMULATION OF SAFETY DRILLING CYCLE OF HORIZONTAL HOLE IN UNCONSOLIDATED SANDSTONE RESERVOIR

在疏松砂岩油藏中钻水平井首先要解决的是井眼失稳问题。室内通过对疏松砂岩储层进行蠕变试验,得到其常温下稳态蠕变的本构方程,并验证砂岩的黏性流变是造成水平井井眼缩径的主要因素。在疏松砂岩储层水平段井眼变形分析中考虑了疏松砂岩的黏弹塑性变形,并综合地应力、钻井液密度以及流变参数对井眼缩径速率的影响,应用FLAC3D进行数值模拟计算,得出了疏松砂岩中水平井井眼随时间变化的缩径率,并据此确定了疏松砂岩储层水平井水平段钻进的安全周期。

The instability of the horizontal hole in unconsolidated sand reservoir is the main topic which must be considered during the horizontal well drilling operation. Obtaining the steady-state creep constitutive equation by the laboratory experiments on unconsolidated sands sample from the some offshore oil-gas field at normal-temperature. This study has verified the viscous deformation of unconsolidated sand is the main factor to affect the shrinkage of horizontal hole. The deformation of horizontal hole was analyzed with considering the visco-elastoplastic deformation of the surrounding rock. The shrinkage rate of the horizontal hole was calculated with FLAC3D with considering the influence of in-situ stress,mud density and rheological parameter, and the safety drilling cycle determine is determined based on the shrinkage rate of the horizontal hole.