二维核磁共振测井在川西海相超深水平井中的应用

Application of 2D NMR Logging in Western Sichuan Marine Ultra Deep Horizontal Well

摘要: 四川盆地川西气田海相雷口坡组气藏产能建设主要采用水平井完井。出于安全考虑，水平井一般不进行中子与密度放射性测井，中子和密度测井曲线的缺失对雷口坡组碳酸盐岩储层评价带来很大挑战，主要体现在岩性与储层物性参数难以准确定量评价，流体性质难以判别。在部分水平井中进行了二维(T₂, T₁)核磁共振测井数据采集，水平井核磁共振测井特征具备与直井相似的谱峰特征。核磁共振测井信息不受固体骨架的影响，克服了以体积模型为基础的传统测井方法受井眼、岩性以及地层水矿化度影响的缺陷，无需作泥质、岩性等方面校正，提供的地层信息更客观可靠。选择二维(T₂, T₁)核磁共振测井法进行了水平井流体性质判别以及储层物性参数计算，弥补了常规测井资料缺失造成的缺陷，为川西海相气田的产能建设提供了有利支持。

Abstract: Horizontal well completion is mainly adopted for productivity construction of marine Leikoupo Formation gas reservoir in West Sichuan gas field, Sichuan Basin. Neutron and density radioactivity logging is generally not carried out for horizontal wells for safety reasons. The lack of neutron and density logging curves poses a great challenge to the evaluation of carbonate reservoir in Leikoupo Formation, which is mainly reflected in the difficulty in accurate quantitative evaluation of lithology and reservoir physical parameters, and the difficulty in distinguishing fluid properties. 2D (T₂, T₁) nuclear magnetic resonance logging data were collected in some horizontal wells. The nuclear magnetic resonance logging characteristics of horizontal wells are similar to those of vertical wells. The nuclear magnetic resonance logging information is not affected by the solid framework, which overcomes the defects of the traditional logging method based on the volume model that is affected by the borehole, lithology and salinity of formation water. It does not need to correct the shale and lithology, and the formation information provided is more objective and reliable. The 2D (T₂, T₁) nuclear magnetic resonance logging method is selected to distinguish the fluid properties of horizontal wells and calculate the physical parameters of reservoirs, which makes up for the defects caused by the lack of conventional logging data and favorably supports the productivity construction of Western Sichuan marine gas field.