关键词: 高闭合应力, 致密储层, 储层改造, 加重压裂液, 支撑剂

Abstract: High-quality reservoir is developed in the deep layers of the lower assemblage of the southern margin of Junggar Basin, where embeds tremendous oil and gas resources. However，the reservoir there has a general burial depth greater than 5 700 m，a temperature greater than 130 ℃，a closure stress gradient greater than 0.02 MPa/m，an average porosity less than 10%，an average permeability less than 0.1×10 -3 μm 2 and strong heterogeneity. Due to the poor physical properties，high Young's modulus and high Poisson's ratio of the reservoir，fracturing faces great challenges in respect of fracture initiation，high pump pressure and efficient use，which present higher requirements for wellbore integrity，fracturing materials and technology. Through field study and practices，a fracturing technical system for tight reservoir with high closure stress has been developed，which is centered on the technology to reduce wellhead operating pressure and integrated with proppant combination and optimization technology and treatment parameter optimization technology. Thus，the bottleneck of the fracturing technology for deep reservoir with high temperature and pressure has been broken through. It has been successfully applied in 3 wells since 2020. After fracturing treatment，well-GQ6 has seen significant effect: the maximum daily oil production is 97.97 m 3 and the daily gas production is 2.03×10 4 m. This technical system provides new perspective for deep oil and gas exploration in the southern margin of Junggar Basin.

Key words: high closure stress, tight reservoir, reservoir fracturing, weighted fracturing fluid, proppant