涩北一号疏松砂岩气田的防砂策略

Sand control strategy for Sebei-1 unconsolidated sandstone gas field

涩北一号气田储层埋藏深度差异大,主要为第四系粉砂岩和泥质粉砂岩,胶结疏松,泥质含量高,成岩性差,气井所出砂为细粉砂,平均粒度0.04～0.07mm,常规防砂技术基本无效或效果很差,防砂难度极大,属世界性难题,这严重地制约了该气田的高效开发。近10年来,纤维复合防砂、高压一次充填防砂等先进防砂技术在涩北气田得到了实践应用,但在取得很大成功的同时也暴露出一系列新的问题。基于涩北一号气田一类、二类和三类气藏的不同特性,考虑不同井段、不同类型的储层岩石胶结差异,研究出按相近类型气藏合层开发的新开发模式、基于气田不同储层临界生产压差值的适合于临界出砂的压差生产方式以及加密井网等保守性防砂策略。实际开发效果对比结果表明,该保守开发策略解决了以往防砂方式带来的经济效益差、采收率低、有效期短等问题。

The Sebei-1 gas field is characterized by large difference in buried depth and its reservoir mostly consists of quaternary siltstone and argillaceous siltstone which are of loose cementation,large clay content and poor lithologic character.Since the sand from gas wells is the fine silt with the average grain size ranging from 0.04 to 0.07mm,the conventional sand control technique nearly has no effect or bad effect.So,sand control of Sebei-1 is hard and it is one of the difficulties in the world,which restricts the development of this gas field with high efficiency.In recent 10 years,although such advanced technologies as asbestos-fabric composite sand control and high pressure pack sand control have been applied in Sebei-1 gas field and got big successes,a series of new problems are exposed.Based on the different characteristics of the type Ⅰ,Ⅱ and Ⅲ gas reservoir in Sebei-1 gas field,considering the difference among the different types of reservoir cementation in different well sections,this paper studied a new mode of multi-zone commingled development due to the similar gas reservoirs,production mode of pressure difference suitable to critical sanding output based on critical production pressure drop of different reservoirs in a gas well and conservative sand control strategy by the infill well pattern.By comparing the practice effect,it is shown that this conservative strategy can be the solution to poor economic interests,low recovery and short valid period brought by the previous sand control.