酸性有机钛交联剂的合成及其在压裂液中的应用

The synthesis and application of acidic organic titanium cross-linking agent for fracturing fluid

摘要:

以钛酸丁酯为主剂，多元醇为络合剂合成了一种酸性有机钛交联剂，并以部分水解聚丙烯酰胺作为稠化剂，制备了部分水解聚丙烯酰胺压裂液。研究了交联剂中钛酸丁酯的质量分数，丙三醇与乳酸的质量比以及pH对冻胶交联延时、黏度的影响，得到较佳的合成条件。考察了质量分数为0.5%的部分水解聚丙烯酰胺，m（HPAM）：m（有机钛）=100:0.5时，有机钛/部分水解聚丙烯酰胺压裂液的性能，交联延时300s；耐温性能优异，在95℃，170s-1的条件下连续剪切90min，黏度保持在50mPa.s以上，体系耐温耐剪切性能良好；由线性黏弹性范围内动态频率扫描结果可知，G’>G”，是典型的黏弹性流体；常温下，V（压裂液）：V（石英砂）=100:30时，沉降速度0.025mm/s；破胶后，破胶液黏度低于5.0mPa.s且残渣量较低，对储层伤害小。

Abstract:

Using tetrabutyl titanate as the main agent, polyhydric alcohol as the complexing agent, a type of acid organic-titanium cross-linking agent was synthesized. HPAM is used as a thickener. The study has examined the effects of the content of butyl titanate, the ratio of complexing agent and the pH value on the delayed gelling and the viscosity.The performance of the organic titanium/ HPAM fracturing fluid shows that: the delayed time is 300s, the viscosity of the system was still higher than 50 mPa?s after shearing for 90 min at the temperature of 95℃ and the shearing rate of 170s-1, so the fracturing fluid possessed good temperature tolerance and shearing resistance. By the result of the dynamic frequency scanning, G’>G”, so it is a typical viscoelastic fluid. When the sand ratio was 30% in volume, settling velocity was 0.025mm/s. It is less harmful to reservoir because the viscosity of the gel breaking liquid is lower than5.0mPa?s and the residue content is low after gel breaking.