Application of Anti-collapse Aluminum Matrix Drilling Fluid System in Jilin Oilfield

摘要

This study deals with the complex problems of wellbore collapse and hole shrinkage during drilling process in Jilin Oilfield. Analysis of lithological characteristics and mineral compositions of the representative reservoir cores, revealed that the reservoir cores have microcracks development in the region. The cores mainly composed of brittle shale and soft mudstone with high contents of illite-smectite, belonging to the strata of strong water-sensitivity and easy to collapse. Based on the principles of aluminum chemistry, optimization and compounding of aluminum salt anti-collapse inhibitors was experimentally formulated. The formation of aluminum matrix drilling fluid system in combination with other additives was also established, and evaluation of the system's rheology, fliter loss, temperature resistance, inhibition and anti-pollution were carried out. Finally, the aluminum matrix drilling fluid system with strong anti-collapse capacity was developed. The on-site applications of 14 wells in Jilin Oilfield related blocks show that compared to the previous anti-collapse system, the aluminum matrix drilling fluid system eliminated the problems of sticking by fast dropping, hang sticking during pulling out of hole and slacking during running in hole caused by wellbore collapsing and hole shrinkage, thus, greatly reducing the accidents' rate.