强抑制强封堵深水钻井液的制备与性能评价

Preparation and Performance Evaluation of Deepwater Drilling Fluid with Strong Inhibition and Plugging

针对深水钻井中钻井液黏土水化抑制性和封堵性能不足、低温流变性差等问题,以烯丙基磺酸钠(AS)、三羟乙基烯丙基溴化铵(THAAB)和甲基丙烯酸甲酯(MMA)为原料制得多羟基低聚物黏土水化抑制剂PDWC。在常规水基钻井液中加入10%KCl和0.7%PDWC,得到密度为1.1 g/cm^3的强抑制强封堵深水钻井液体系。通过红外光谱仪、热重分析仪和凝胶色谱法表征了PDWC的结构,研究了强抑制强封堵深水钻井液的封堵性、润滑性和抗温抗盐性。结果表明,PDWC的相对分子质量为2.2×10~4,抗温可达280℃,强抑制强封堵深水钻井液体系具有良好的抑制和封堵性能。红土滚动回收率高达93.5%,人造岩心在滤液中的常温常压线性膨胀高度仅为1.7 mm。在0.69 MPa的条件下,钻井液在模拟砂床中侵入30 min后的深度为4 cm。钻井液的抗温和抗盐能力较好,其低温流变性和润滑性能良好,满足深水钻井工程需要。

In order to solve the shortcomings of deepwater drilling fluid such as the low degree of hydration inhibition,poor performance of plugging and low temperature rheology,a polyhydroxy oligomer clay hydration inhibitor PDWC was prepared by sodium allyl sulfonate(AS),three hydroxyethyl allyl ammonium bromide(THAAB)and methyl methacrylate(MMA)as raw materials. A high inhibitive and plugging deepwater drilling fluid with the density of 1.1 g/cm3 was developed by adding 10% KCl and 0.7% PDWC to the conventional water-based drilling fluid. The structure of PDWC was characterized by infrared spectrometer, thermogravimetric analyzer and gel permeation chromatography,and the plugging,lubricity,temperature resistance and salt resistance of strong plugging inhibitive deepwater drilling fluid were studied. The results showed that the relative molecular mass of PDWC was 2.2×104,the temperature resistance ability of PDWC was up to 280℃. The deepwater drilling fluid system had good inhibition and plugging performance. The system’s clay recovery rate reached as high as 93.5% and artificial core’s room temperature and pressure linear expansion height was only 1.7 mm. The intrusion depth of drilling fluid in simulated sand bed was only 4 cm after intruding 30 min at 0.69 MPa. The drilling fluid had nice temperature and salt resistance performance,low temperature rheology and good lubrication performance,which met the needs of deepwater drilling engineering.