安塞油田致密砂岩井体积压裂现场先导试验

Field pilot test of volume fracturing in tight sandstone well in Ansai Oilfield

关键词:  体积压裂  致密砂岩油藏  现场试验  微地震监测  安塞油田 

Key words:  volume fracturing  tight sandstone reservoir  field test  microseismic crack monitoring  Ansai Oilfield

摘要:

安塞油田属典型的“低压、低渗、低产”致密砂岩油藏,储层物性差,非均质性强,新投产油井需要通过压裂改造方能建产。随着油田的开发,受闭合压力影响,迫使油井需进行二次或三次压裂改造恢复其生产能力。受选井条件限制,常规增产措施后增油幅度小,压裂后很难形成新的裂缝,导致油井措施后有效期短。以安塞油田杏18-A为例,以“大液量、大排量、大砂量、低砂比”的工艺体系开展了混合水体积压裂先导探索试验,并配合开展了微地震裂缝监测。现场应用结果表明,较常规压裂而言,该工艺形成的裂缝体积增大了126.7%,平均单井日增油提高1.7倍,在储层重复压裂方面表现出明显的改造优势。 

Abstract:

Ansai Oilfield is a typical tight sandstone reservoir with “low pressure, low permeability, low production”, which has poor reservoir property and strong heterogeneity. The new well build the production only by fracturing. With the development of oilfield, the well affected by the closure pressure need second fracture or third fracture to restore production. However, by the limit of well selection conditions, conventional measures of increasing production only make low oil increasing, and the validity period is short since fracturing is hard to make new fracture. Taking Ansai Oilfield Xing 18-A as an example, this article specified the construction scheme and take mixed water volume fracturing pilot test with “large fluid measure, large displacement, large sand measure, low sand ratio” while taking the microseismic crack monitoring. Field application results showed that compared with conventional fracturing, the crack volume which was formed by this technology enlarged 126.7%, and the average single well daily oil-increasing improved 1.7 times. It showed obvious advantage in reservoir refracturing.