Method for identifying post-fracturing productivity classification in tight gas reservoirs based on principal component analysis

The tight sandstone reservoirs in the Linxingdong area of the Ordos Basin are characterized by low porosity, high irreducible water saturation, low gas saturation, and strong heterogeneity, with conventional logging methods showing low accuracy in identifying reservoir fluid properties. This paper proposes a method based on principal component analysis (PCA) for identifying post-fracturing productivity classification in complex tight gas reservoirs. Initially, the fluid productivity classification type of the test layers was determined by integrating gas and liquid production data from the fracturing and production stages. Subsequently, logging data were utilized to select curves sensitive to reservoir fluid properties, and a calculation formula for the fluid property identification factor D was established based on PCA. The classification of reservoir fluid productivity in the study area was then identified based on the D value. The results indicate that the fluid property identification factor method based on PCA performed well in the study area, with an accuracy of 83%. Compared with other conventional methods, this approach fully exploits geophysical logging data, has strong generalizability, and provides data support for the formulation and adjustment of subsequent development plans.