松散破碎地层钻进高吸水树脂堵漏剂合成与评价

Synthesis and evaluation of highly absorbent resin plugging agent for drilling in loose broken formation

地质钻探过程中面临着诸多挑战,其中井漏问题尤为突出,特别是在破碎地层中,井漏问题的发生频次更高。因此,研制适用于松散破碎地层的钻井液体系维持破碎地层快速钻进具有重要的实际意义。通过优化实验确定了适用于破碎地层堵漏的惰性材料及配方,采用水溶液聚合法制备了高吸水树脂(Super Absorbent Polymer,SAP),0~100℃条件下的吸水倍数在100倍以上;使用无渗透钻井液漏失仪对SAP的粒径及浓度进行了优选,0.3%的4~8目SAP为最优选择,最终优选出破碎地层堵漏钻井液体系配方:水+8%膨润土+0.1%黄原胶+0.6%HVCMC+2%核桃壳+1%云母片+2%特种纤维+0.3%的4~8目SAP。该钻井液体系能够完全封堵10~20目砂粒充填床,在0.69 MPa压力下漏失量为0 mL,在0~60℃范围内具有良好的流变稳定性,表观粘度25~48 mPa·s、动切力6~18 Pa、API滤失量为7~11 mL、润滑系数0.311,在松散破碎地层堵漏中体现出了良好的应用前景。

There are many challenges in the process of geological drilling,among which the problem of leakage is particularly prominent,especially in fractured formations,which occurs more frequently.Therefore,it is of great practical significance to develop a drilling fluid system suitable for loose broken formation to maintain rapid drilling in broken formation.The inert material and formula suitable for plugging in the broken formation were determined by optimization experiments.Meanwhile,Super Absorbent Polymer(SAP)was prepared by aqueous solution polymerization,and the water absorption ratio was more than 100 times under the condition of 0~100℃.The non⁃permeable drilling fluid loss instrument was used to optimize the particle size and concentration of SAP,and 0.3%of 4~8 mesh SAP was the best choice.Finally,the formula of the drilling fluid system for plugging the broken formation was optimized:water+8%bentonite+0.1%xanthan gum+0.6%HV-CMC+2%walnut shell+1%mica sheet+2%specialty fiber+0.3%SAP of 4~8 mesh.The drilling fluid system can completely plug the sand filling bed of 10~20 mesh,the loss is 0 mL at 0.69MPa pressure,and has good rheological stability in the range of 0~60℃.The apparent viscosity is between 25~48mPa·s,the dynamic shear force is 6~18 Pa,the API filtration loss is 7~11mL,and the lubrication coefficient is 0.311.It shows a good application prospect in plugging loose broken strata.