A Low Cost High Temperature Seawater-Based Guar Gum Fracturing Fluid
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摘要: 海上油气田压裂由于条件限制,采用淡水配制压裂液导致运输成本高、周期长。海水配制压裂液,碱性交联环境螯合剂加量大,材料成本高,耐温能力一般。针对以上情况采用钛酸四异丙酯、硫酸锆等物质作为反应原料,分步合成有机钛锆交联剂。经核磁碳谱、交联剂沉析后扫描电镜表征,表明交联剂为有机螯合物,动静态同步激光光散射仪表征交联剂尺寸,表明交联剂粒子直径主要为1~100 nm,具有良好的反应活性。该交联剂在中性条件下即可交联,适应海水等高矿化度水质配制压裂液,其交联微观形态为蜂窝状六元网格状结构,结构稳定,黏弹性相比单钛交联有明显的提升,耐温能力可达180 ℃以上。在中海油南海区域施工实验一口海水配液高温井,效果良好。Abstract: In offshore fracturing operation, formulating a fracturing fluid with fresh water results in high transportation cost and long time of formulation. If seawater is used to formulate the fracturing fluid, a large amount of chelating agents which crosslink in alkaline environment shall be used, and this results in high material cost, while the ability of the fracturing fluid formulated to resist high temperature may not be satisfactory. To solve this problem, an organic titanium zirconium crosslinking agent is stepwise synthesized with reactants tetra-isopropyl titanate and zirconium sulphate etc. Characterization of the reaction product with NMR and SEM (after precipitation of the crosslinking agent) shows that the crosslinking agent is an organic chelating agent. The particle sizes of the crosslinking agent are distributed in a range of 1 nm to 100 nm, as measured with dynamic and static synchronous laser scattering instrument, and this indicates that the crosslinking agent has excellent reactivity. This crosslinking agent can crosslink in neutral conditions, a good property for formulating fracturing fluids with high salinity waters such as seawater. The microstructure of the crosslinking product is a stable honeycomb-like hexagonal grid structure. With this organic titanium-zirconium crosslinking agent, the fracturing fluids formulated have better viscoelasticity than the fracturing fluids formulated with crosslinking agents containing only titanium. The high temperature resistance of the fracturing fluids formulated using the organic titanium-zirconium crosslinking agent is 180 ℃. Field application of this new crosslinking agent in formulating a fracturing fluid with seawater for fracturing a high temperature well of CNOOC in south China Sea has obtained good results.
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Key words:
- High salinity /
- Seawater /
- Guar gum /
- High temperature resistant /
- Low cost
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表 1 配液水部分离子分析
离子含量 自来水/(mg·L−1) 海水/(mg·L−1) 钠离子 37 8860.0 钾离子 22 386.0 钙离子 20 387.0 镁离子 4 1220.0 硼离子 0 2.5 氯离子 47 18 570.0 硫酸根离子 31 4200.0 总矿化度 161 33 655.5 表 2 交联体系滤液岩心伤害率
岩心号 伤害前渗透率/
mD伤害后渗透率/
mD伤害率/
%平均伤害
率/%南1-1# 0.111 75 0.084 56 24.325 24.619 南1-2# 0.122 46 0.091 95 24.912 -
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