破碎地层取心技术研究与应用

Technology Research and Application of Coring Technology in Broken Formation

摘要:

目前在取心钻探工程中，仍然存在破碎地层取心率低、取心钻效低等问题。本文根据岩性和破碎成因对破碎地层进行了分类，可分为坚硬破碎、软弱破碎、脆性破碎和松散破碎；分析了破碎地层取心时易发生的问题：岩心冲蚀、堵心、磨心、丢心。认为造成破碎地区取心问题的主要原因为，坚硬破碎为岩心碎涨体积增加导致岩心管堵塞，松散破碎为冲洗液对岩心的冲蚀；软弱破碎和脆性破碎则是碎涨和冲蚀二者都有，并且钻速较高堵心不易发现。破碎地层提高采取率的应对措施：低钻压、低转速、低泵压和高性能水基聚合物冲洗液取心工艺；防冲蚀内外阶梯侧喷式取心钻头、复合式岩心爪、双管单动绳索取心器。相关技术在河北省唐山市宋家营南综合气调查ZG1孔煤层取心进行了应用，煤系地层整体取心率达到了98.77%。该工艺对破碎地层钻探取心具有一定的参考借鉴意义。

Abstract:

At present, in the core drilling project, there are still some problems such as low core rate in broken formation and low efficiency of core drilling. In this paper, the broken strata are classified into hard broken, soft broken, brittle broken and loose broken. The problems of core erosion, core blocking, core grinding, core loss and countermeasures are analyzed. Using low weight on bit, low speed, low pump pressure and high performance water based polymer mud coring technology; Anti-erosion core bit, compound core claw, double pipe single action rope core, can effectively solve the problem of broken formation core. The relevant technology has been applied to ZG1 coal seam coring in Songjiaying South comprehensive gas survey, Tangshan City, Hebei Province, and the coring effect is good. This technology has certain reference significance for similar stratum drilling coring.