杨税务潜山超高温非均质碳酸盐岩气藏储层改造技术

Reservoir stimulation technologies for the ultra high temperature heterogeneous carbonate gas reservoir in Yangshuiwu buried hill

杨税务潜山碳酸盐岩储层具有典型的超高温(170~200℃)、高压、非均质性强等特点,纵向上发育3套层状储层段,近几年储层改造效果一直不理想。研究认为影响该地区储层改造效果的主控因素有:(1)储层改造的工程设计不适合强非均质性的地质特征;(2)射孔厚度过大造成单层改造裂缝的延伸长度小;(3)现有液体体系及配置不适合长缝的形成;(4)套管压裂方式常造成套管及环空水泥环的破坏,从而造成套管破损、井口环空带压等风险隐患。针对上述问题,通过技术攻关和现场实践,形成了针对性配套工艺:(1)减小储层改造厚度,提高压裂改造强度,增大横向改造面积;(2)优化压裂液配置,提高缝网支撑力度;(3)优化施工工艺,创新裂缝导流能力保持工艺;(4)优化管柱工艺,降低风险事故。该技术在杨税务潜山2口井进行了现场实践,均取得了良好的效果,为高温深层碳酸盐岩储层改造提供了技术借鉴。

The carbonate reservoir of Yangshuiwu buried hill is characterized by ultra high temperature(170-200℃),high pressure and strong heterogeneity.Three sets of layered reservoir sections are vertically developed.And in recent years,the reservoir stimulation effect has not been satisfactory.The research results show that the main factors controlling the reservoir stimulation effect in this area are as follows.First,the engineering design of reservoir stimulation is not suitable for the geological characteristics of strong heterogeneity.Second,the perforation thickness is excessive,leading to short propagation length of single-layer stimulated fracture.Third,existing fluid system and its configuration are not applicable to the formation of long fractures.Fourth,casing fracturing mode often brings damage to casing and annulus cement sheath,and consequently results in potential risks,such as casing damage and sustained casing pressure.To deal with these problems,a series of special matching technologies were developed by conducting technological research and field practice.First,decrease reservoir stimulation thickness,improve fracturing stimulation intensity and increase lateral stimulation area.Second,optimize the configuration of fracturing fluid,and improve fracture network support strength.Third,optimize construction technology and innovate in the fracture conductivity maintenance technology.Fourth,optimize string technology and reduce risk accidents.These technologies have been applied in two wells in Yangshui buried hill,and good results have been achieved,which provide technical reference for high temperature deep carbonate reservoir reconstruction.