基于热采井防砂的水平井射孔方位优选研究

Optimization of Perforation Orientation for Horizontal Wells Based on Sand Control of Thermal Recovery Wells

稠油热采井防砂有效性是制约海上稠油热采井高效开发的关键因素。为控制热采水平套管井出砂,优选水平井射孔方位,本文基于岩石力学理论,分析了地应力和注入高温蒸汽对井壁处应力状态的影响。获得井壁应力状态后,根据岩石破坏的德鲁克-普拉格(Drucker-Prager)准则进行出砂预测,建立水平井射孔出砂临界生产压差计算模型,并利用有限元分析软件ABAQUS模拟某热采水平套管井井筒沿不同地应力方向钻进时,射孔方位与临界生产压差的敏感性。研究结果表明,沿水平方位射孔时,临界生产压差较小,均小于0.8MPa,沿垂直方位射孔时,临界生产压差较大,均大于1.0MPa。热采水平套管井射孔方位沿着垂直方向相对安全,应尽量避开水平危险方位。建议热采水平套管井射孔尽量处于相对安全的方位范围内,避免水平方向射孔,以获得更大提高生产压差的空间,提高油井产量。

Sand control effectiveness is the key factor to restrict the efficient development of offshore heavy oil thermal recovery wells.In order to control sand production and optimize perforation orientation of the hori-zontal well,this paper analyzes the influence of in-situ stress and injected high-temperature steam on stress state at borehole wall based on rock mechanics theory.After the stress state is known,sand production is predicted according to the Drucker-Prager criterion of rock failure,and the calculation model of critical producing pressure difference for sand production of horizontal well perforation is established.The finite element analysis software ABAQUS is used to simulate the sensitivity of perforating orientation to critical producing pressure difference during drilling of thermal recovery horizontal casing wells along different in-situ stress di-rections.The results show that the critical producing pressure difference is smaller than 0.8 MPa when perforat-ing along the horizontal direction,and larger than 1.0 MPa when perforating along the vertical direction.The perforation orientation of thermal recovery horizontal casing well is relatively safe along the vertical direction,and the dangerous horizontal direction should be avoided as far as possible.It is suggested that the thermal recovery horizontal casing well should be perforated in a relatively safe range as far as possible instead of horizontal direction,so as to obtain more space to improve the producing pressure difference and increase the oil well production.