长庆胡尖山油田固井工艺技术

胡尖山区块A8井区是长庆油田原油增产的主要区块.该区块主力油层长6层属欠压实易漏地层,地层复杂,而且裸眼段长,油层多、油层段长,水层活跃、油水同层,井眼质量差、井径扩大率大,因此开发井、预探井在钻井、固井中多次发生严重漏失,影响了钻井速度及固井质量.通过综合分析固井中存在的问题及难点,对固井工具、水泥浆体系、现场施工进行一系列研究及改进,通过3口井施工,固井质量达到了要求,基本解决了长6层固井中存在的难点,形成了一套切实可行的解决易漏长裸眼、低压多油层固井工艺技术.现场应用表明:根据平衡压力固井原则,优选前置液、水泥浆体系,优化现场施工参数,精细现场施工措施,确保了注水泥、候凝过程不发生漏失;采用三凝水泥浆体系封固长裸眼、多油层、易漏失、水层活跃地层,行之有效,固井质量好;粘滞性前置液(CND)性能优越,完全满足塞流顶替的要求,提高了长裸眼顶替效率;通过加入复合早强稳定剂GQD,优化改进了漂珠低密度、超低密度水泥浆性能;触变性、快凝水泥浆性能优越,完全满足了并达到固井要求,确保了固井质量.

Research on cementing technology for Hujianshan Block in Changqing oilfield

A8 Area of Hujianshan Block is a main oil stimulated zone in Changqing oilfield. And Chang6 layer, the main layer, is an uncompacted one in which lost circulation potentially occurs. In addition, because of other characteristics such as complex geological configuration, long open hole, multiple long oil zones, active water layer oil and water exist in one layer, and problems of poor hole quality and high well enlargement rate, severe lost circulation during drilling or cementing process happened many times. The penetrating rate was lowered down, and the cementing quality was affected. Based on comprehensive analysis on the problems and difficulties in cementing job, research and improvement were made on cementing tools, cement slurry and onsite operation, then a practical cementing technology for easy losing long open hole and low pressure multiple oil zones was formed. This technology was applied in 3 wells with satisfactory results. Field using showed that: 1) to select pad fluid and cement slurry, optimize the onsite operating parameters, and better the operational measures on the basis of balanced drilling theory, no occurrence of lost circulation in the process of cementing or waiting-on-cementing was ensured. 2) it is practical to use three-stage cement slurry to seal long open hole, multi-oil zone, easy losing formation and water active reservoir, and the cementing job quality was improved. 3) the viscous pad fluid CND has excellent properties, fulfilling requirement of plug flow displacement with improved displacement efficiency. 4) with the compounded early strength stabilizer GQD added in, properties of microsphere light-weight slurry and ultra-low density cement slurry were improved. The thixotropic and quick setting slurry is predominant in propertiesin cementing operation, and the cementing quality was ensured.