The Wide Area Electromagnetic Method of Tight Gas Fracturing Monitoring: A Case Study from Well L in Jinhua Area of Sichuan Basin

The tight gas reservoir of Jurassic Shaximiao Formation in Jinhua area of Sichuan Basin is characterized by low porosity, extra low permeability and undeveloped natural fractures, which requires reservoir reconstruction to form artificial fractures. Due to the complex distribution direction of the river channel and the small two-way stress difference, the fracture morphology formed by the reconstruction is not clear. With the optimization of the fracturing technology in this block, the microseismic method used in the previous stage can no longer meet the demand of the current fracturing effect monitoring. In order to better clarify the mechanism and effect of tight gas reservoir reconstruction, this paper takes Well L in Jinhua area as the research well, and applies the wide field electromagnetic method (WFEM) to monitor tight gas fracturing effect for the first time. The results show that: (1) the extension of the artificial fracture is related to the spreading of the channel sand, and the artificial fracture is more likely to develop in the direction of the well-developed channel sand. (2) The overall repetitive reconstruction rate of fractured section is only 0.54%, and the mutual stress interference effect between the fractured sections is small. (3) The swept length of cluster pores at both ends of the reconstructed fracture is large, and the swept length of cluster pores in the middle is small. (4) The swept length and area of cluster pores in fractured stage are related to the spacing of clusters within the stage. (5) The swept length of cluster pores and swept area of single stage have a certain correlation with reservoir parameters such as porosity. The above understanding has some implications for the efficient development of tight gas.