辽河油田古潜山储层钻井取心技术

为了提高辽河油田古潜山储层的岩心收获率及取心质量，研究了适合古潜山储层的钻井取心技术。通过分析辽河油田古潜山储层的地层特征，用排除法确定了造成单筒岩心收获率低及取心质量差的主要原因，提出了相应对策。首先，优化了取心钻头，将切削齿由原来的3~5个改为10个，采用Z3型金刚石复合片与硬质合金连接方式，设计了低冲蚀PDC钻头水眼结构。然后，改进了取心工具，增加了隐式篮式岩心爪和引心套、内筒扶正器、堵心指示器、防堵心装置，换用内壁光滑的铝合金内筒。最后，对钻压、转速、排量等取心技术参数进行了优化。辽河油田9口井的现场应用表明，机械钻速从0.55 m/h提高至2.79 m/h，岩心收获率从51.13%提高至89.97%。研究结果表明，辽河油田古潜山储层钻井取心技术能有效提高机械钻速、岩心收获率和取心质量，降低井下安全风险，可推广应用于坚硬破碎地层的取心作业中。 

Coring Techniques for Buried Hill Reservoirs in Liaohe Oilfield

In order to enhance the core recovery and coring quality for buried hill reservoirs in Liaohe Oilfield,the coring solutions suitable for the buried hill reservoirs has been studied.Through analyzing the stratigraphic characteristics of buried hill reservoirs in Liaohe Oilfield,the method of exclusion was used to determine the causes of low core recovery and poor coring quality,and counter measures were put forward.First,the coring bit was optimized.Instead of 3-5 cutting teeth originally,the optimized coring bit had 10 cutting teeth made of Z3 diamond compact on cemented carbide base,and port arrangement of low erosion.Next,the coring tool was improved.An implicit basket type core catcher and cited heart shoes,inner barrel centralizer,coring jam indicator and anti-jam coring system were added to the coring tool,and the smooth aluminum alloy inner tube was used.Finally,the technical parameters of WOB,RPM,pumping rate,etc.were optimized.Field test in 9 wells of Liaohe Oilfield indicated the ROP had increased from 0.55 m/h to 2.79 m/h and the core recovery had increased from 51.13% to 89.97%.The results showed that the coring techniques for buried hill reservoirs in Liaohe Oilfield could enhance penetration rate,core recovery and coring quality,and reduce downhole security risks,which could be applied in hard,broken formation coring operation.