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川中地区沙溪庙组致密砂岩储层可压性评价实验

Experimental Evaluation on the Fracability of Tight Sandstones in the Shaximiao Formation in Central Sichuan Basin

Environment and Resource / 2026,8(1): 39-47 / 2026-03-06 14 7

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• Authors: 卢怡霖 赵峰
• Information:

  西南石油大学地球科学与技术学院，成都

• Keywords:
  Central Sichuan area; Shaximiao formation; Tight sandstone reservoir; Reservoir; Engineering geological characteristics; Fracability evaluation
  川中地区; 沙溪庙组; 致密砂岩储层; 工程地质特征; 可压性评价
• Abstract: Tight sandstone reservoirs in the Shaximiao Formation of the central Sichuan Basin are primarily developed in the first member of the Shaximiao Formation and exhibit promising exploration and development potential. However, systematic evaluation of engineering sweet spots and fracturing effectiveness has not yet been conducted, resulting in insufficient guidance for fracturing engineering design. Therefore, it is necessary to investigate the engineering geological characteristics of tight sandstone reservoirs in the study area. Experimental results indicate that the reservoirs have an average porosity of 4.16% and an average permeability of 0.46 mD. Pores are predominantly concentrated in the range of 1–5 μm, with the presence of some microfractures. The mineral composition is dominated by quartz, potassium feldspar, and plagioclase, with an average clay mineral content of 6.44%. The average brittleness index of the reservoirs is 45.74%, the in-situ stress difference coefficient ranges from 0.17 to 0.30, the average fracture pressure is 45.14 MPa, the average fracture toughness is 0.48 MPa•√m, and the average fracture development index is 0.91. This study establishes a fracability evaluation model applicable to tight sandstone reservoirs in the Shaximiao Formation of the central Sichuan Basin. By integrating field operations, it analyzes and summarizes the characteristics of high-productivity wells achieved through fracturing stimulation and proposes strategies for reservoir stimulation in wells with suboptimal fracturing outcomes. 川中地区沙溪庙组致密砂岩储层主要发育于沙溪庙组一段，具备良好的勘探开发潜力，但目前尚未开展系统的工程地质特征及压裂效果研究，导致压裂工程设计指导性不强。因此，需开展研究区致密砂岩储层工程地质特征研究，实验结果表明：储层孔隙度平均孔隙度为4.16%，平均渗透率为0.46mD，孔隙主要集中于1～5μm，发育部分微裂缝；矿物组分以石英、钾长石、斜长石为主，平均粘土矿物含量为6.44%。储层平均脆性指数为45.74%，地应力差异系数集中于0.17～0.30之间，破裂压力平均为45.14MPa，平均断裂韧性为0.48MPa•√m,平均裂缝发育指数为0.91。文章建立了适用于川中地区沙溪庙组致密砂岩储层的可压性评价模型，与现场施工相结合，分析总结了目前压裂改造高产井的特征，提出了针对压裂效果不及预期井的储层改造思路。
• DOI: https://doi.org/10.35534/er.0801005 (registering DOI)
• Cite: 卢怡霖，赵峰．川中地区沙溪庙组致密砂岩储层可压性评价实验［J］．环境与资源，2026，8（1）：39-47.