摘要
内蒙古查干凹陷苏一段致密砂岩油藏地质特征复杂，断块小，储层矿物成熟度低、结构成熟度低和胶结物质量分数高，储层物性整体偏差。储层孔隙和裂缝不均匀分布，储层浅层以低孔、低渗为主。查干凹陷苏一段采用中或高黏度胍胶压裂液和小液量（200~300 m3）、小排量（3.0~4.5 m3/min）、高砂比（20%~25%）的常规压裂工艺，存在井筒周围改造规模小、压裂液返排率低、储层伤害大、油井产量低、稳产期短等问题。针对此问题，通过室内实验优选出快速溶解、低黏度、高效减阻与低伤害的滑溜水压裂液体系，并实施大液量（600~900 m3）、大排量（8~12 m3/min）、低砂比（8%~16%）段塞加砂的深度压裂工艺技术（简称“两大一低”），增加了压裂改造范围，提高了增产效果。
Abstract
The geological features of tight sandstone reservoir of Su1 Formation in Chagan Sag are complex with small fault blocks. The reservoir has the characteristics of low mineral maturity, low structural maturity and high cement content, so the overall reservoir physical property is poor. The distribution of reservoir pores and fissures are uneven, the shallow reservoir is dominated by low porosity and low permeability. The conventional fracturing process, which uses medium or high viscosity guanidine glue fracturing fluid and small volume of 200-300m3, small displacement of 3.0-4.5m3/min, high sand ratio of 20%-25%, has some problems such as small scale of stimulation around the wellbore, low fracturing fluid return rate, heavy reservoir damage, low well production and short stable production period, etc. In view of the problems, the system of slippery water fracturing fluid with fast dissolution, low viscosity, high efficiency and low damage was selected through indoor experiments. And the deep fracturing technology of slug sand injection with large volume of 600-900 m3, large displacement of 8-12 m3/min, low sand ratio of 8%-16%(referred to as "two large and one low") was implemented to increase the fracturing stimulation range and improve the production.
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