缝洞型碳酸盐岩油井抑漏堵水技术研究及现场试验

Research and Field Test of Loss-Control and Water Shut-Off Technology in Vuggy-Fractured Carbonate Oil Wells

  • 摘要: 缝洞型碳酸盐岩油藏普遍发育高渗透带和裂缝,注入水易沿优势通道突进至井筒,导致堵水失败。针对该问题,基于漏失控制的井筒堵水设计理念,选用碳酸钙作为主要漏失控制材料,研究形成了井下控漏—挤水泥—控压返排的组合堵水技术。首先,分批次泵注碳酸钙悬浮液封堵高渗通道,提升储层承压能力;随后,挤水泥并控压返排多余的水泥浆,以避免返顶;最后,进行电缆射孔与酸化投产,重建产能通道。室内试验表明,黄原胶可有效携带碳酸钙颗粒并控制井筒漏失;设计的水泥浆体系具备良好的流变性和封堵性能。现场试验表明,A井堵水后注入指数降低80%,含水率由53%降至10%,取得了明显的治理效果。研究结果表明,基于漏失控制的不动管柱堵水技术可以解决缝洞型油藏堵水过程中的水泥浆漏失问题,具有经济、高效和环保等优点,为类似油藏的堵水作业提供了新的技术途径。

     

    Abstract: High-permeability zones and fractures are widely developed in vuggy-fractured carbonate reservoirs, and injected water can easily break through along the predominant pathway and enter the wellbore, resulting in a high failure rate of water shut-off operations. To address this issue, a wellbore water shut-off design concept based on loss control was proposed. The method used calcium carbonate as the primary loss control material, forming a comprehensive water shut-off technology involving downhole loss control, cement squeeze, and pressure-controlled flowback. Firstly, calcium carbonate suspension was injected in batches to seal the high-permeability channels, thereby enhancing the pressure-bearing capacity of the reservoir. Subsequently, the cement was squeezed, and the excess cement slurry was controlled to be returned to the wellbore to prevent the wellhead from being clogged. Finally, cable perforation and acidizing were performed to reconstruct the production capacity channel. The experimental results show that xanthan gum can effectively carry calcium carbonate particles and control lost circulation. The designed cement slurry system possesses excellent rheological properties and sealing performance. Field test results show that in Well A, the injectivity index decreases by 80% after water shut-off, and the water cut drops from 53% to 10%, achieving great effects. Studies have shown that the water shut-off technology based on loss control can solve the problem of cement slurry leakage during water plugging in vuggy-fractured reservoirs. It has the advantages of cost-efficiency, high efficiency, and environmental friendliness and provides a new technical approach for water shut-off operations in similar reservoirs.

     

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