万米深井上部大尺寸井眼钻柱动力学特性研究  

Drill string mechanical behaviors of large-size borehole in the upper section of a 10000 m deep well

作　　者：祝效华[1] 李柯 李文哲[2] 贺明敏 佘朝毅[2] 谭宾 ZHU Xiaohua;LI Ke;LI Wenzhe;HE Mingmin;SHE Chaoyi;TAN Bin(Southwest Petroleum University,Chengdu,Sichuan 610500,China;PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China;CNPC Chuanqing Drilling Engineering Company Limited,Chengdu,Sichuan 610051,China)

机构地区：[1]西南石油大学 [2]中国石油西南油气田公司 [3]中国石油川庆钻探工程有限公司

出　　处：《天然气工业》2024年第1期49-57,共9页Natural Gas Industry

基　　金：国家自然科学基金杰出青年项目“钻井提速理论与方法”(编号:52225401)。

摘　　要：油气勘探已向更深、更复杂的超深层的万米勘探新领域推进,但上部大尺寸井眼给万米深井的钻井提出了巨大挑战:岩石硬和返速低导致钻速慢,大尺寸井眼内剧烈振动导致钻具裂纹多发,钻压小则钻速慢,钻压稍大则下部振动快速加剧从而导致大尺寸钻具使用寿命远低于预期。为此,在对比研究了深地川科1井(以下简称SDCK-1井)和毗邻8000 m超深井上部井段钻柱振动问题基础上,基于全井钻柱系统动力学模型和数值仿真方法,针对性研究了大尺寸井眼中的钻柱动力学特性。研究结果表明:①井眼尺寸越大,钻头和下部钻具的振动越剧烈,SDCK-1井二开大尺寸井眼与邻井中等尺寸井眼相比(井深500 m处),其钻头及下部钻具振动强度均值分别增加了48.0%和41.5%,比SDCK-1井三开中等尺寸3000 m井深的钻头及下部钻具振动强度均值分别高了29.0%和2.9%;②相同井眼尺寸和岩石特性情况下,下部钻具组合比钻柱整体长度对钻头振动的影响更大,优化下部钻具组合能够明显改善钻头振动,保护钻头,同时还可以提高钻头破岩能量利用效率实现钻井提速;③在大尺寸井眼中钻头破岩激励向上传播,横向振动衰减慢于轴向振动衰减,大尺寸钻头扭矩更大且钻压和扭矩波动更加明显,因此从保护下部钻具的角度出发,大尺寸井眼钻具组合对抑制横振更加有效;④大尺寸井眼中下部钻具弯矩和弯矩波动更大,现场频繁出现的钻具裂纹除受控于整体振动强度较大以外,交变弯矩是裂纹发生的重要原因。结论认为,该研究成果揭示了超深井大尺寸井眼中钻柱的动力学特性,指出了应着重控制横振和交变弯矩,该认识可以为超深井上部大尺寸井眼钻井提供技术指导。The oil and gas exploration has been advancing to the new fields in the more complex ultra deep strata of 10000 m deep,while the upper large-size borehole poses great challenges to the drilling of 10000 m deep wells.Hard rock and low drilling fluid return speed result in low rate of penetration(ROP),and the severe vibration in the large-size borehole induces multiple cracks in drilling tools.When the weight on bit(WOB)is small,the ROP is low;and when the WOB is slightly large,the vibration of the bottom hole assembly(BHA)is intensified rapidly,which causes the service life of the large-size drilling tool much shorter than expectation.To address this problem,this paper comparatively researches the string vibration in the upper section of Well SDCK-1 and its neighboring ultra-deep well(8000 m deep),and then specifically analyzes the drill string mechanical behaviors of large-size borehole by means of full-hole string system mechanical model and numerical simulation.And the following research results are obtained.First,the larger the borehole size,the more severe the vibration of the bit and the BHA.The vibration intensity of the bit and BHA at the depth of 500 m in the second-spudding large-size borehole of Well SDCK-1 is about 48.0%and 41.5%respectively higher than that at the same depth in the medium-size borehole of its neighboring well,and about 29.0%and 2.9%respectively higher than that at the depth of 3000 m in the third-spudding medium-size borehole of Well SDCK-1.Second,under the same borehole size and rock behaviors,BHA has greater influence on bit vibration intensity than the whole length of drill string.Therefore,optimizing the BHA can significantly reduce the bit vibration intensity,thereby protecting the bit,and increasing the bit's rock breaking energy utilization efficiency can improve the ROP.Third,in the large-size borehole,the rock breaking excitation of the bit propagates upward,and the transverse vibration attenuation is slower than the axial vibration attenuation,so the more effective way to pr

关 键 词：超深井 科探井 SDCK-1井 大尺寸井眼 钻头振动 钻柱动力学 钻具裂纹 

分 类 号：TE247[石油与天然气工程—油气井工程]