高性能合成基钻井液体系的研制及性能研究

Development of and Study on a High Performance Synthetic Base Drilling Fluid

针对高温高压复杂井安全密度窗口较窄的难题,笔者通过分子结构设计和合成,研发了抗温达232℃的新型抗高温乳化剂、抗高温降滤失剂和抗高温有机土,并在此基础上构建了一套高性能合成基钻井液体系。实验结果表明,该乳化剂乳化率高达95%以上,形成的乳状液液滴尺寸分布均匀。降滤失剂与乳化剂、有机土协同增效,进一步提升了体系的乳化稳定性、高温高压流变性和降滤失功能。与传统的合成基钻井液相比,该体系在高密度下具有低黏度、低切力、沉降稳定性好、高温热稳定性好及高温高压滤失量低等优点,从而有助于解决高温高密度钻井液因结构强度太大而造成的憋泵、启动泵压过高、当量循环密度(ECD)变化大而诱发的井漏及井壁失稳等难题,为满足石油勘探开发高温高压井作业安全提供了技术保障。

A high performance synthetic drilling fuid has been developed to deal with narrow safe drilling window associated with high temperature high pressure wells. The synthetic base drilling fuid was formulated with three main additives a new high temperature emulsifer which is resistant to high temperatures to 232 ℃, a high temperature flter loss reducer and a high temperature lipophilic clay, which were developed through molecular structure design and synthesis. Laboratory experimental results showed that the emulsifying capacity of the emulsifer was as high as 95%, and the emulsion formed with the emulsifer had droplets of evenly distributed sizes. The synergistic action among the flter loss reducer, the emulsifer and the lipophilic clay further improved the emulsion stability, HTHP rheology and fltration control property of the drilling fuid. Compared with conventional synthetic drilling fuids, this drilling fuid has those advantages such as low viscosity, low gel strength, good suspending capacity, superior high temperature stability and low HTHP flter loss. These advantages are helpful to resolving drilling problems associated with high structural strength of drilling fuid such as overpressure of pump during pumping and at startup, severe fuctuation of equivalent circulation density （ECD） resulting in lost circulation and wellbore collapse. The use of the new synthetic base drilling fuid has provided technical support for the safe operation of HTHP wells in petroleum exploration and development.