ABSTRACT
During the drilling of oil and gas wells in the Niger Oilfield, barite is often used as a weighting agent for drilling fluid mud. However, under the combined action of temperature and pressure, precipitation is likely to occur to block the wellbore, and conventional blockage removal agents cannot effectively solve the problem. In this study, aiming at the problem of wellbore blockage removal in the Niger Oilfield, the composition of scale samples was analyzed by the Soxhlet extraction method and the chelating agent LY-CGJ-1 was selected from 6 blockage removal agents. LY-CGJ-1 (10%) was determined as the optimal mass fraction through the experiment of the BaSO4 dissolution rate. At the same time, the reaction threshold temperature of LY-CGJ-1 to BaSO4 was determined to be 50°C, and the time for the second injection of the blockage removal agent was determined to be between 48 to 72 hours. The interaction mechanism between LY-CGJ-1 and Niger Oilfield wellbore scale was analyzed by FT-IR. The LY-CGJ-1 blockage removal agent selected in this study is helpful in improving the efficiency of blockage removing work by more than 50% and enhancing the oil recovery of the Niger Oilfield.
