Coking Properties Of Heavy Oil In Porous Media And Its Seepage Experiment Research

In- situ combustion is a promising technology in heavy oil exploitation. In recent years, due to the transformation of oilfield development technology for some oilfields with steam injection technology, ISC technology has been widely concerned. Because of the lack of understanding of ISC technology in complex physical and chemical process, the industrial promotion of the technology is very slow. It’s necessary to do indoor experiments to help with deeper understanding of the mechanism of ISC. One of the key problem in the ISC technology is the coking of heavy oil in the porous media and its influence on seepage. Based on the ‘reaction – seepage’ experiment platform with ultra high temperature and multiphase flow reservoir in Research Institute of Petoleum Exploration and Development(RIPED), the paper study the coking of heavy oil in porous media and its effects on seepage by experiment.For experimental purposes, I involved in building and debugging the ‘reaction – seepage’ experiment platform with ultra high temperature and multiphase flow reservoir. the platform not only simulates the porous medium structure and oil field with high temperature and pressure, but also measures the permeability. It can be applied to kinds of experimental study, like reaction of simulated field condition and multiple-phase fluid flow.To evaluate the coking properties of heavy oil under different reaction conditions, I use unit quality coking of heavy oil as one of the important indicators, and I build a fixed experimental program based on the construction of experimental platform: coking of the heavy oil—cleaning the residual oil—combustion and measurement. To evaluate the changes of the absolute permeability of the coking blocking, the experiment of seepage has a controllable experimental program: coking of the heavy oil—cleaning in situ—measuring the permeability. And I use the SEM to observe the changes of the pore structure of the coking. Choosing the ordinary heavy oil as the target heavy oil in certain oilfield in Xinjiang and 140~160 mesh glass beads as model sand, and doing carbon analysis of heavy oil, PDSC exothermic chemical analysis and the analysis of the four components of heavy oil to characterize heavy oil.In the experimental platform, I ran lots of experiments and considered many factors affecting coking in heavy oil, including temperature, pressure, atmosphere, the rate of venting and stay time of the temperature in the air atmosphere, and measured the mass of coke deposition to characterize the influence of various factors. The coking experimental results show that the initial coking temperature under different atmosphere is quite different(under air atmosphere the temperature is 225 oC and under N2 is 425oC)but pressure has no obvious effect on the initial coking temperature. And various factors( temperature, pressure, atmosphere, the rate of venting and stay time of the temperature)have influence on the mass of coke in different extent. The results of the experiment of permeability and SEM indicate that coke deposit mainly on particle surfaces and pores and coke deposition reduces permeability.In this paper, the experimental data helps to further understand the coking of heavy oil in ISC and provides the base for the lab simulation experiment and oilfield well testing.