西南石油大学学报（自然科学版）2023，Vol.45Issue(6)：95-103,9.DOI:10.11885/j.issn.1674-5086.2021.10.05.34
准噶尔南缘冲断带破碎地层井壁稳定性机理
Wellbore Stability Mechanism of Fractured Formation in the Thrust Belt of Southern Margin of Junggar Basin
摘要
Abstract
The southern margin of Junggar Basin is characterized by complex geological structure,fractured formation and poor drillability,and frequent lost circulation,tending to stick and collapse during drilling.In order to achieve safe drilling of fractured formation in the southern margin,the lithology,hydration and rock mechanics characteristics of the formation represented by Tugulu and Hutubi anticlines are studied,and the clay mineral content,hydration strength and compressive strength of different formation are compared.Combined with the seismic interpretation section and the compressive strength loss model,the mechanism of wellbore instability and the mechanism of drilling fluid stability in the fractured formation in the southern margin are analyzed.The results show that the southern margin of the formation is dominated by mudstone and sandstone,the whole rock minerals are dominated by clay minerals,plagioclase and quartz,and the clay minerals are dominated by illite and illite/smectite,and the hydration characteristics are highly heterogeneous,including extremely strong-weak dispersion and strong-medium-weak expansion.The hydration expansion and dispersion of clay minerals and the expansion and expansion of micro-pores and fractures in the fractured formation around the well lead to the decrease of formation compressive strength,the increase of collapse pressure,and the decrease of drilling fluid density window,leading to wellbore instability.Reasonable drilling fluid density,excellent hydration inhibition,comprehensive porosity sealing,strict high temperature and high pressure filtration and efficient lithology carrying are the necessary measures to achieve safe drilling and wellbore stability in the fractured formation in the southern margin.The research results can provide a reference for the design of key parameters of drilling fluids in deep complex fractured formations in the southern margin and even Junggar Basin.关键词
准噶尔盆地/南缘/破碎地层/井壁稳定性/钻井液Key words
Junggar Basin/southern margin/fractured formation/wellbore stability/drilling fluid分类
能源科技引用本文复制引用
叶成,任涛,尹泽斌,李成,白杨..准噶尔南缘冲断带破碎地层井壁稳定性机理[J].西南石油大学学报（自然科学版）,2023,45(6):95-103,9.基金项目
国家自然基金面上项目(52274008) （52274008）
国家重点研发计划(2019YFA0708303) （2019YFA0708303）
中国石油-西南石油大学创新联合体科技合作项目(2020CX040102,2020CX040201) （2020CX040102,2020CX040201）
