水平井裸眼封隔器密封结构优化研究

Research on Optimization of Sealing Structure of Open-hole Packer in Horizontal Wells

针对水平井压缩式裸眼封隔器存在的密封性差、坐封力低、胶筒与井壁间存在间隙等问题,对其密封结构进行改进与优化,设计出一种凸球形隔环和凹球形胶筒组相结合的新型密封结构。运用ABAQUS软件模拟密封结构封隔器胶筒的坐封情况,获得胶筒组轴向接触压力的分布规律,并分析胶筒硬度和摩擦因数对接触压力的影响。结果表明:新型密封结构凸球形隔环在轴向压缩胶筒的同时也起径向压缩作用,提高了胶筒与井壁和中心管间的接触压力,增强了封隔器的密封性能;胶筒与井壁间的接触压力随着胶筒硬度和摩擦因数的增大而增大,但过大的摩擦因数会导致下胶筒接触压力明显减小,应选择硬度和摩擦因数合适的胶筒,从而保证封隔器的密封可靠性。

Aimed at some problems of compression-type open-hole packer of horizontal wells such as poor sealing performance,low setting force and gap existed between rubber and well wall, a new sealing structure composed of convex spherical spacer rings and concave spherical rubbers was put forward by optimizing and improving the conventional packer sealing structure. The setting situation of sealing structure of packer spherical rubbers was simulated by ABAQUS software, the distribution regularities of contact pressure of the rubbers in axial direction were obtained, and the effects of hardness of rubber and friction coefficient on contact pressure were analyzed. The results show that the new sealing structure of convex spherical spacer ring plays a role in radial compression and axial compression of rubber at same time, so the contact pressure of rubber and well wall, rubber and central tube is improved, the sealing performance of packer is enhanced. The contact pressure of rubber and well wall is increased along with the increasing of hardness of rubber and friction coefficient. However, too big friction coefficient will lead to the decrease of contact pressure of the lower rubber, so rubber with appropriate hardness and friction coefficient must be chosen, in order to ensure the reliability of sealing packer.