泡沫钻井液研究及其应用

Research on foam drilling fluid and its application

通过对泡沫钻井液的保护油层机理和其性能与温度、压力、时间及各种试剂的关系分析得知,泡沫钻井液对渗漏地层有良好的防漏、堵漏效果,具有较强的净化能力,尤其在大斜度井段和水平井段的钻井过程中,解决了沉积井眼下侧的岩屑床等问题。现场应用表明,泡沫钻井液适用于地层裂缝发育、漏失严重、低压以及超低压地层钻井,能满足地质录井要求,利于及时发现、保护油气层。泡沫钻井液性能稳定.具有静液柱压力低、润滑性和携岩性能好、滤失量小、摩阻小、抗污染和助排能力强以及对油层伤害小等优点,适用于压力系数较低地层的钻井。该体系能有效地降低事故的发生率,防止了井壁坍塌;满足了低压、低渗地层以及大斜度井段和水平井段的钻井要求。

Analysis on reservoir protection mechanism of foam drilling fluid and relation between its performance and temperature, pressure, time and all ingredients reveals that foam drilling fluid has good lost circulation control and plugging ability, and good cleaning efficiency; especially in high-inclination well and/or horizontal wells, it clears off the cutting beds settled at the lower side of the borehole.Field using indicates that foam drilling fluid is suitable for drilling the formations with fracture developing, severe leakage, low pressure and ultra-low pressure problems, and can satisfy the requirements of logging and formation protection.The drilling fluid also has such advantages as stable property, low hydrostatic fluid column pressure, good lubrication and cuttings transportation capacity, little filtrate loss and friction loss, strong resistance to contamination, and little damage to formation, etc..With the using of the foam drilling fluid, accidents can be effectively reduced and well sloughing can be prevented remarkably.It is very useful in drilling low pressure low permeable formation and high-inclination and horizontal sections.