基于测井数据的砂岩三轴抗压强度预测模型

岩石的抗压强度对于优化钻头选型具有重要的意义。针对石油钻井中常遇到的砂岩提出了一种基于测井资料的三轴抗压强度解释模型，该模型是以测井声波、密度、伽马值等数据为主，以单轴抗压强度的解释结果为基础，结合围压下砂岩力学性质实验以及砂岩孔隙度变化实验结果所建立的。研究表明：围压对砂岩强度有较明显的影响，随着围压的增大，砂岩的三轴抗压强度也增大；砂岩的孔隙度随围压的增大而减小，且服从对数函数变化规律。

MODELING ON TRIAXIAL COMPRESSIVE STRENGTH OF SANDSTONE BASED ONWELL-LOGGING DATA

The compressive strength of rocks is very important to optimization of drill bits selection. Aiming at thesandstones which are frequently encountered in the oil drilling, a triaxial compressive strength model which is based on logging data is put forward. The model is established on the basis of acoustic logging, bulk density, gamma ray counts and the results of uniaxial compressive strength. The experiments’ results about the nature of confining pressure of sandstone mechanics and changes in sandstone porosity are also considered. It is shown that sandstone strength is influenced by confining pressure significantly. With the increasing of lateral pressure, the compressivestrength is also increased. Porosity is reduced with the increasing of confining pressures, which conforms to the rule of logarithmic function.