基于ABAQUS顯示動(dòng)力學(xué)的柔性鉆具水平鉆進(jìn)動(dòng)力學(xué)特性分析
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DynamicCharacteristicsofHorizontalDrillingwithFlexible Drill StringBased on ABAQUS ExplicitDynamics
Liu XinHuang ZhongweiWu Xiaoguang LiGenshengShi HuaizhongWang JiaruiWang Minghao （StateKeyLaboratoryofPetroleumResources andEngineering，China UniversityofPetroleum-Beijing）
Abstract：During thedrilingofultrashort-radiusradial horizontal well with flexibledrill string，the vertical shift of wellbore trajectoryaffects the encounteringrateoftarget points.To revealthedynamic characteristicsof horizontal drilling with flexibledrillstringandreduce the vertical shiftofwellboretrajectory，ahorizontaldrilling model offlexibledrillstring was built based onABAQUS explicit dynamics and calculations were carried out subsequently. Theresearch focuses on the motion offlexible drilling string，bit atitude，rock breaking characteristics，trajectory deviationcharacteristics，formationadaptabilityandthesensitivityof trajectory andovercut to weightonbit（WOB）. Theresearch resultsshowthattheprocessof driling with flexibledrillstring exhibits aspiral motion posture，rotating around the borehole axis while rotating around itsown axis.The bit breaks rocks in anapproximately conical scanning posture，andtheprocessofbreaking rocks hasasymmetry.Thefield testverifies theaccuracyofthemodel， andthe rajectorydeviationofflexibledrillstring mainlyoccurs in the gravitydirection，explainingthereason forthe vertical trajectorydeviation inthefieldtest.Thecorrespondingtrajectorydeviationrates insoft，mediumand hard rocksare 4.44% ， 3.71% and 3.52% respectively，and are higher underhigh WOB conditions.Anincrease in WOB reduces the bit lateral aggressivityand overcut，and the preferred WOB for horizontal drilling is （30±5）kN. The research results provide a feasible solution to the study of the motion of flexible drill string.
Keywords：horizontal well；flexibledrill string；trajectory deviation；ultrashort-radius；explicit dynamics： numerical simulation
0 引言
柔性鉆具超短半徑徑向水平井技術(shù)是一種側(cè)鉆技術(shù)，其能夠在垂直井眼內(nèi)的數(shù)個(gè)地層中鉆出多個(gè)水平分支，可穿透近井污染帶，極大地增加泄流半徑。（剩余12430字）