水力射孔对套管强度的影响研究

STUDY ON INFLUNCE OF HYDRAULIC PERFORATION ON CASING STRENGTH

水力射孔技术是一种新型的完井方式,深穿透水力射孔技术辅助定向水力压裂可以实现油气层改造和油气井增产。但是,水力射孔套管会在孔眼处造成应力集中,使得局部应力过大而削弱了套管和水泥环的强度,可能会影响套管的使用寿命。因此,文章利用有限元软件建立了射孔套管的三维有限元模型,分析了水力射孔后套管管体的应力分布,重点研究了水力射孔参数—孔密、孔径、孔深、射孔方位角等对套管强度的影响规律。分析结果表明,沿着最大水平地应力方向深穿透水力射孔,选择合适的孔密、孔径可将射孔对套管的损害降至最小。研究结果为提高水力射孔完井设计水平提供了一定的参数依据。

Hydraulic perforation is an emerging completion technique. Oriented fracturing aided by water-jet deep perforation can achieve the purpose of improving reservoir and enhancing oil well production. The 3D finite element mechanical model of hydraulic perforated casing was established with FEA software, and the effects of hydraulic perforating parameters on the mechanical strength of casing were studied comprehensively. The results indicate that by means of selecting properly shot density and perforation diameter, water-jet deep perforation in the direction of the maximum horizontal in-situ stress could minimize the damage on the casing caused by hydraulic perforation. The conclusion provides criterion of perforation parameters to improve the hydraulic perforation completion design.