关键词: 冻胶阀, 智能胶体, 欠平衡完井

Abstract: Conventionally, casing valve was used for underbalanced completion. But it cost a lot and could not achieve underbalanced completion once failed. So gel valve was studied. This is an intelligent chemical colloid for underbalanced completion. Once gelatinized in borehole, it has certain strength and can withstand compression performance. It can play the isolation effect and prevent liquid which is in the well into the reservoir. It can form static sealing in the wellhole and form dynamic seal with the completion tube, then control the oil and gas overflow. After well completion, it can achieve gel breaking liquefaction, and use nitrogen or water return discharge. The product adapts to the temperature between 55℃ and 100℃ and bearing pressure from 2 MPa to 5MPa. Now gel valve technology has been applied to oil and gas wells. The types of underbalanced completion include hanger screen pipe completion and open-hole completion, with the success rate reaching 100%. Gel valve can not only ensure successful underbalanced completion, but can also reduce the cost remarkably. It is significant to enriching underbalanced drilling technique connotation and expanding underbalanced drilling technology.

Key words: gel valve, intelligent colloid, underbalanced completion