新型速钻复合桥塞的开发与应用

桥塞分段压裂技术是目前国内外非常规油气藏增产改造的主体技术之一,具有分段压裂层数不受限制、能实现大规模大排量体积压裂、桥塞钻铣完后井筒畅通等优势,其技术核心是桥塞工具。但此前该技术和速钻桥塞均需进口,价格高且影响非常规气藏工业化开发的周期。通过力学分析、结构优化、材料优选和实验评价,成功开发出了具备高钻磨效率和高密封承压能力的新型速钻复合桥塞,并实现了复合材料生产成型、桥塞设计加工国产化。新型速钻复合桥塞主要包括丢手机构、锚定机构和密封机构,其中丢手机构通过剪切销钉控制坐封工具与桥塞丢手;锚定机构具有芯轴防转动和防下移功能,可有效提高钻磨效率;密封单元和保护套采用弧面结构设计,能提高密封承压能力。其主要部件均采用特殊增强材料和树脂基体复合而成,并经过缠绕和模压等工艺加工成型,材料强度高、可钻性好、钻屑易返排。新型速钻复合桥塞已现场应用20余井次,动作灵活、密封可靠、钻磨效率高,能够满足非常规气藏储层改造的要求。

Development and application of a new fast drilling composite plug

As one of the main unconventional reservoir stimulation technologies, bridge plug staged fracturing is widely used in the world at present. With the bridge plug as the key tool, this fracturing technology has the advantage of unlimited fracturing stage, large scale and high rate SRV fracturing, and smooth flow in wellbore after drilling and milling. Unfortunately, the technology and fast drilling bridge plug need to be imported at a high price thus affecting the cycle of commercial development of unconventional gas reservoirs. A new fast drilling composite bridge plug has been developed after mechanical analysis, structure and material optimization, and experimental evaluation, thus significantly enhancing the efficiency of drilling and milling and loading capacity, and making localized the production and molding of this composite material as well as the plug design and manufacturing. This new fast drilling plug includes releasing, anchoring and sealing gadgets. The releasing gadget controls sitting tool and plug releasing by a shear pin. The anchoring gadget can prevent mandrel rotation and moving down, thus enhancing the drilling and milling efficiency. The loading capacity of sealing element and protective envelope is improved by adopting an arc surface design. The main elements are all composed of a special reinforced material and resin matrix, and shaped through filament winding and compression molding. Such a design brings about high drillability and easy flowback of drilling cuttings. The application of this new plug to more than 20 wells has proven that it is flexible in operation, reliable in sealing and high in drilling and milling efficiency, satisfying the requirement of unconventional reservoir stimulation.