超深井射孔冲击动载荷引起封隔器断裂失效分析  

Analysis on packer fracture failure caused by dynamic load of perforating impact in ultra-deep well

作　　者：练章华[1] 万智勇 王飞文 赵朝阳 史君林 LIAN Zhanghua;WAN Zhiyong;WANG Feiwen;ZHAO Zhaoyang;SHI Junlin(National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation//Southwest Petroleum University,Chengdu,Sichuan 610500,China;Engineering Technology Research Institute,PetroChina Xinjiang Oilfield Company,Karamay,Xinjiang 834000,China)

机构地区：[1]油气藏地质及开发工程全国重点实验室·西南石油大学 [2]中国石油新疆油田公司工程技术研究院

出　　处：《天然气工业》2024年第6期44-51,共8页Natural Gas Industry

基　　金：国家自然科学基金项目“极端条件下气井管柱耦联振动力学行为与控制基础理论研究”(编号:5197041669)。

摘　　要：中国超深层油气资源丰富,超深井油气开发过程中常采用一体化管柱完成射孔—试油—酸化三联作业,作业过程中超深井射孔冲击动载荷频繁导致封隔器断裂失效。为解决上述问题,基于弹塑性有限元法,结合实际井下测得的射孔管串起爆瞬态冲击动力学载荷边界条件,开展了新疆某地X1井射孔作业RTTS封隔器(全开式挂壁封隔器)—减震器管串瞬态冲击动力学有限元仿真分析,建立了减震器二阶带阻尼的质量—弹簧力学系统模型,从理论上对比分析了双减震器的减震效果与有限元分析结果的可靠性。研究结果表明:(1)在射孔爆轰0.09 s和0.21 s时刻,中心管接头螺纹处分别出现805.4 MPa和925.1 MPa两个应力峰值,超过了管材的屈服强度和抗拉强度,且冲击波引起的交变应力导致局部位置开始发生裂纹失效,裂纹逐渐扩展到整个截面,造成螺纹接头断裂;(2)根据仿真模型计算结果以及中心管结构尺寸分析,发现其螺纹部分结构尺寸偏小,导致峰值应力超过其抗拉强度造成断裂失效;(3)建议采用中心管上部螺纹连接处镦粗2~3 mm的改进方案,其最大应力可降低27%以上,可明显提高结构强度;(4)使用双减震器能有效降低射孔管串上部冲击载荷,理论计算指出双减震器比单减震器的振幅降低约50%,其最大应力降低约42%。结论认为,研究成果可为超深井RTTS封隔器管柱安全射孔作业提供理论和技术支撑,并将有力推动我国超深层油气资源的高效勘探开发。China is rich in ultra-deep oil and gas resources.In the development process of ultra-deep oil and gas,the integrated string is often used for perforating-testing-acidizing operation.In the process of this operation,however,the dynamic load of perforating impact in ultra-deep well frequently causes packer fracture failure.In order to solve this problem,this paper carries out the finite element simulation of transient impact dynamics of absorber string on the RTTS packer(fully-open hook wall packer)used for perforating in Well X1 in Xinjiang,based on the elastic-plastic finite element method,combined with the actually measured boundary conditions of the transient impact dynamic load at the moment of perforating string detonation.Based on this,a second-order damping mass-spring mechanical system model of shock absorber is established.In addition,the damping effect of double shock absorbers and the reliability of finite element analysis results are theoretically analyzed and compared.And the following research results are obtained.First,at the time of 0.09 s and 0.21 s of perforation detonation,two peak stresses of 805.4 MPa and 925.1 MPa appear at the thread of the central pipe joint,respectively,exceeding the yield strength and tensile strength of the pipe.Moreover,the alternating stress caused by the shock wave induces local crack failure,and the cracks gradually expand to the entire section,causing the failure of the threaded joint.Second,the calculation results of the simulation model and the structure size of the central pipe show that the structure size of the threaded part is so small that the peak stress exceeds its tensile strength,causing fracture failure.Third,it is suggested to adopt the improvement plan of upsetting 2-3 mm at the upper threaded connection of the central pipe,which can reduce the maximum stress by more than 27%and improve the structural strength.Fourth,the application of the double shock absorbers can effectively reduce the impact load on the upper part of the perforating string.Theoret

关 键 词：超深井 射孔作业 封隔器断裂 减震器 公螺纹接头 冲击载荷 数值模拟 

分 类 号：TE921[石油与天然气工程—石油机械设备]