Session: 11-10-04 Development of Unconventional Reservoirs-4

Paper Number: 79908

79908 - Experimental Study on Asphaltene Deposition Characteristics in Yudong Block of Yingmaili Oilfield 

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 (SGO) and the conduct of PVT tests. Then, the
high-magnification microscopic visualization solid deposition instrument was employed to study
the asphaltene deposition characteristics of gas-bearing crude oil under reservoir conditions.
Last, differential scanning calorimetry (DSC) experiment was carried out to measure the initial
asphaltene precipitation temperature (IAPT) and quantitative characterization the deposition
amount of the ground degassed crude oil. Results show that the IAPT curve of gas-bearing
crude oil at different pressures will have an inflection point near the bubble point pressure.
Under constant pressure cooling condition, the asphaltene in the gas-bearing crude oil are
precipitated in the form of crystal nucleus and gradually aggregate, entangled with each other,
and the amount of deposition increases as the temperature decreases. Phase envelope 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 IAPT of the surface
degassed crude is 34.05 °C, with instantaneous deposition reaching a maximum of 0.01178 %
at 16.2 °C and cumulative deposition reaching 8.34 % at -20 °C. This research provides a
strong support for effectively overcoming the asphaltene blockage challenge in Yudong block.

Presenting Author: Hang Xu China University of Petroleum Beijing

Authors:

Hang Xu China University of Petroleum Beijing
Fujian Zhou China University of Petroleum Beijing
Yuan Li China University of Petroleum Beijing
Liyan Zhu China University of Petroleum Beijing
Hao Bai China University of Petroleum Beijing
Erdong Yao China University of Petroleum Beijing