Study on efficient sealing drilling fluid and its application in Caofeidian block
In response to the frequent occurrence of drilling operation blockages caused by the instability of deep shale wellbore in the Caofeidian block of the Bohai oilfield,the key research direction is to improve the plugging ability of drilling fluid.The potassium chloride polymer drilling fluid system applied in this block was improved,and an efficient plugging water-based drilling fluid system suitable for this block was formed by opti-mizing the plugging materials and dosage indoors.The comprehensive performance of the system was evaluat-ed.The experimental results showed that the system had good inhibitory,sealing,calcium resistance,and strong resistance to drilling debris pollution.The on-site application results showed that the performance of the actual drilling fluid was stable,the filtration was less than 4 mL,the drilling operation efficiency was 92.8%,and the wellbore stability was good,providing technical support for the efficient development of deep oil and gas resources in this block.