摘要
中国南海莺琼盆地具有温度梯度高、地层压力高、安全密度窗口窄的特点,在高温高压状态下经常出现钻井液流变性控制困难、井漏、电测遇阻和储层污染等问题。根据该区块地层的特点,通过大量的室内研究,在聚磺体系的基础上,引入甲酸钾作为抑制剂,优选了磺化材料及抗温聚合物,在提高抑制性的同时,有效地降低了体系的活度,通过加重剂的优化,改善钻井液的流变性,同时使其具有低的高温高压失水,密度2.4 g/cm3的体系抗温可达200℃。现场应用结果表明,该钻井液体系具有良好的抗温性和流变性,高温高压失水低,泥饼质量好,电测结果显示,该钻井液体系具有良好的储层保护效果。
Yingqiong Basin in the South China Sea is characterized by high temperature gradient, high formation pressure, narrow safe density window, so such problems often occur in the condition of high temperature and high pressure as difficulty in control of drilling fluid rheology, lost circulation, electric logging blocked and reservoir pollution. Based on the characteristics of the formations of this Block and through large amount of indoor research, the potassium formate as inhibitor was introduced based on polysulfide system, and the sulfonated material and temperature resistant polymer were selected, which, while improving inhibition, effectively reduced the activity of the system and, through the optimization of weighting materials, improves the rheology of drilling fluid. At the same time, the drilling fluid has low HTHP water loss. A system with density of 2.4 g/cm3 can resist a temperature of up to 200 ℃.Field application results show that the drilling fluid system has good temperature resistance and rheological property, low HTHP water loss and good quality of mud cake. Electric log results show that this drilling fluid system has good reservoir protection effect.
引文
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