陆丰易垮塌地层随钻核磁测井钻井液技术

Drilling Fluid Technology for Nuclear Magnetic Logging While Drilling in Collapsed Strata of Lufeng

南海东部海域的陆丰古近系储层物性较差、岩性变化快、非均质性强、孔隙结构多样,需要通过随钻核磁测井明确油藏的孔隙结构。针对现场使用的高矿化度、低液相活度水基钻井液的电阻率较低,容易带来信噪比降低对测井数据的准确性造成影响的问题,在不破坏现场钻井液体系性能的前提下,通过室内试验分析和模拟对高矿化度钻井液进行调整优化:利用聚氨抑制剂替代部分无机盐加量,在降低泥浆矿化度的同时维持泥浆抑制性,满足随钻核磁测井电阻率要求;优选纳米乳胶封堵剂,降低作业过程中因钻遇煤层、泥页岩裂缝发育地层而出现井塌、井垮等复杂情况。基于室内调整优化的钻井液体系,得出随钻核磁共振测井作业与现场高矿化度钻井液应对方法,提出一种用于高温、易垮塌地层随钻核磁测井钻井液在现场应用的工艺方法,并在陆丰油田LF22-1-A3井现场成功应用,对后续相关作业有一定的参考意义。

The Lufeng Paleogene reservoir in the eastern South China Sea has poor physical properties,fast lithological changes,strong heterogeneity,and diverse pore structures.It is necessary to clarify the pore structure of the reservoir through nuclear magnetic logging while drilling.In response to the low electrical resistivity of water-based drilling fluids with high salinity and low liquid phase activity used on site,which can easily lead to a decrease in signal-to-noise ratio and affect the accuracy of logging data,indoor experimental analysis and simulation were conducted to adjust and optimize the high salinity drilling fluid without damaging the performance of the on-site drilling fluid system.Polyamine inhibitors were used to replace some inorganic salt dosages,Maintaining mud inhibition while reducing mud mineralization to meet the resistivity requirements of nuclear magnetic logging while drilling.Optimizing nano latex sealing agents to reduce complex situations such as well collapse and collapse caused by drilling into coal seams and shale fractures during the operation process.Based on indoor adjustment and optimization of the drilling fluid system,a method for dealing with high salinity drilling fluid during drilling nuclear magnetic resonance logging operation and on-site high salinity drilling fluid is proposed.A process method for on-site application of nuclear magnetic resonance logging drilling fluid in high-temperature and easily collapsed formations is proposed,and it has been successfully applied in the LF22-1-A3 well of Lufeng Oilfield,which has certain reference significance for subsequent related operations.