Experimental Study on Asphaltene Deposition Characteristics in Yudong Block of Yingmaili Oilfield

Abstract The oil wells in the Yudong block of Yingmaili area have encountered serious asphaltene deposition problems during production, which adversely affected the productivity of oil wells. Hence, it is necessary to carry out experiments to study the phase behavior of the well fluid and the characteristics of asphaltene deposition. Experimental research began with the preparation of simulated gas-bearing crude oil and the conduct of PVT tests. Then, the laser solid deposition analyzer was employed to study the asphaltene deposition characteristics of gas-bearing crude oil under reservoir conditions. Finally, differential scanning calorimetry experiment was carried out to measure the initial asphaltene precipitation temperature and quantitative characterization the deposition amount of the ground degassed crude oil. Results show that there are four phases areas of “gas-liquid-solid”, “gas-liquid”, “liquid-solid” and “pure liquid” for gas-bearing crude oil at different temperatures and pressures, and temperature is an important factor affecting asphaltene precipitation in Yudong oil wells. The initial asphaltene precipitation temperature of the surface degassed crude is 23.05 °C, with instantaneous deposition reaching a maximum of 0.01178 % at 6.2 °C and cumulative deposition reaching 8.34 % at −30 °C. This research provides a strong support for effectively overcoming the asphaltene blockage challenge in Yudong block.