多尺度纤维韧性水泥浆体系研究与应用

Research and Application of Tough Cement Slurry Systems with Multi-Scale Fiber

针对油井水泥石脆性大、抗拉强度低、抗冲击和抗破裂性能差等问题,优选了3种不同尺度的无机纤维,并通过正交试验进行复配,形成了多尺度纤维增韧剂BCE-230S。考察了BCE-230S加量对水泥浆性能及对应水泥石力学性能的影响,确定了其最佳加量,形成了多尺度纤维韧性水泥浆体系。性能评价试验结果显示,与普通水泥石相比,多尺度纤维韧性水泥石的劈裂抗拉强度、抗压强度及抗冲击功显著提高,杨氏模量显著下降,且水泥浆性能良好。多尺度纤维韧性水泥浆体系在冀东油田低渗透油藏应用了10余井次,2个胶结面的胶结质量较邻井显著提高,后期压裂顺利,试油未见层间窜流。研究结果表明,多尺度纤维韧性水泥浆体系能够解决油井水泥石易脆裂的问题,可以保障井筒密封完整性和固井长期封固质量,具有广泛的应用前景。

To solve the problems of high brittleness,low tensile strength,poor impact resistance and fracture resistance of the cement stone in oil wells,a multi-scale fiber toughener BCE-230S was formed by selecting inorganic fibers in three different scales and conducting orthogonal tests for compound.In addition,the effects of the dosage of BCE-230S on the construction performance of cement slurry and the mechanical properties of cement were investigated,the optimal dosage was determined,by which a tough cement slurry system with multi-scale fiber was formed.The results showed that the splitting tensile strength,compressive strength and impact resistance of the cement stone were significantly improved when compared with common cement.Young’s modulus decreased significantly and the construction performance was ideal.The tough cement slurry system with multi-scale fiber was applied in the low permeability reservoir in the Jidong Oilfield for more than 10 times in the well,and the cementing quality of the two cementing surfaces was measurably improved compared with that of adjacent wells.Fracturing in later stage was successful,and no fluid channeling was observed during well testing.The results indicated that the tough cement slurry system with multi-scale fiber can effectively solve the problem of brittleness of cement stone in oil well,so as to ensure the integrity of the wellbore and the long-term cementing quality,with a potential for wide application.