摘要
川西沙溪庙组储层具有低渗致密的特点,低渗致密气藏改造需要造长缝,增加施工规模是最有效的途径。川孝490D井位于川西新场构造北翼,新场Js2^1储层属于难动用储层,压后返排困难,常规压裂改造后效果均较差。川孝490D井Js2^1砂体垂厚18.8m,孔隙度为14.9%、渗透率1.37×10^-3μm^2,砂体展布范围宽,泥页岩隔层厚度大,盖产层之间地应力差明显,具备大型加砂压裂的基础和条件,由于该井是定向井（最大井斜角为39°）且目的层最大井斜角为28.2°,极大地增大了施工的难度。因此,压前通过测试压裂和分析,并运用FracPT压裂设计软件对施工参数进行设计和优化后,对该井Js2^1储层实施了81m^3大规模加砂压裂先导性试验,同时采用支撑剂段塞、斜坡式线性加砂、全程液氮伴注等工艺,加砂强度达到4.31m^3/m,平均砂比为25%、排量4.0-5.5m^3/min、入地液量541.3m^3,压后返排率达到90%,该层射孔后获天然气0.2×104m^3/d,压后获得天然气无阻流量1.7×10^4m^3/d。Js2^1储层大型加砂压裂的成功实践为高效、经济开发川西低渗致密储层提供了可靠的技术保证,也为同类型气藏勘探与开发提供了宝贵的经验。
The well Chuanxiao 490D is located in the north of Xinchang structure, and the layer Js21 in Xinchang has the characteristics of difficult exploitation, low flowback efficiency and poor fracturing effect. The vertical height of sand in the well Chuanxiao 490D Js21 is 18.8 meters, and the porosity and permeability is 14.9% and 1.37 mD respectively,sand body cover is broad,the thickness of barrier formed by mud shale is large, the stress difference between capping formation and pay formation is great, all these offer the condition and base for massive sand fracturing. But this well is a directional well and the max angle of inclination in target layer is 28.2° which increase the fracturing difficulty greatly. So, before fracturing, the minifrac and analysis is used, and the operation parameter is designed and optimized by using FracPT software, the pilot massive sand fracturing testing is done in Js21 layer and the scale is 81 m3, meanwhile, the technologies of proppant slug, slope linear gravel input and injecting liquid nitrogen full term have been used in this well. At last, sand intensity attained 4.31m3/m, average sand proportion is 25%, delivery rate is 4.0-5.5 m3/min, fracture fluid injected into formation is 541.3 m3, flowback efficiency attained 90%, gas production is 0.2×104 m3/d, open-flow capacity is 1.7×104 m3/d after shooting and fracturing in Js21 reservoir. The successful practice of massive sand fracturing offered dependable technique for exploiting tight and low permeable reservoir in the west of Sichuan.
出处
《钻采工艺》
CAS
北大核心
2007年第4期64-66,5,共3页
Drilling & Production Technology
基金
国家课题:复杂气田采气工艺技术研究(2006BAB03B07)。
关键词
大型加砂压裂
难动用储层
先导性试验
四川西部
massive sand fracturing, difficult exploiting layer, pilot test, west Sichuan
