Three-dimensional physical simulation experiment study on carbon dioxide and dissolver assisted horizontal well steam stimulation in super heavy oil reservoirs

Abstract

There is abundant super heavy oil resource in the world, however, due to the very high viscosity and density, conventional steam stimulation process will result in high steam injection pressure and small heating area, leading to very bad development effect. To improve the development effect of steam injection in super heavy oil reservoirs, a compound stimulation enhanced thermal recovery technology is proposed. Steam injection is conducted through horizontal well assisted by carbon dioxide and oil-soluble composite dissolver, so this kind of technology is called HDCS for short. HDCS technology synthetically utilizes the physical and chemical characteristics of dissolver, carbon dioxide and steam, so that viscosity reduction, mixing and mass transfer, increasing energy and assisting cleanup of the three components are combined. In this paper, three-dimensional thermal recovery physical simulation experiment apparatus is used to conduct the comparison experiments between steam stimulation and HDCS stimulation, to analyze the development advantage and mechanisms of HDCS stimulation. Experimental results indicate that HDCS stimulation realizes the rolling replacement of viscosity reduction effect of dissolver, carbon dioxide and steam, keeping the oil in steam front with a low-viscosity, and enlarging the viscosity reduction range of super heavy oil by steam injection. Besides, the dissolver injection beforehand decreases the subsequent steam injection pressure, and the dissolution and release of carbon dioxide in super heavy oil can complement the reservoir energy. Compared with the condition after conventional steam stimulation, after HDCS stimulation the steam has larger swept volume and heating range, and the content of heavy component and viscosity of crude oil decreases by larger amplitude. The properties of super heavy oil are improved better than conventional steam stimulation. HDCS stimulation significantly improves the development effect of steam in super heavy oil reservoirs.

The Research of Vapor Phase Front Migration Rules in Steam Assisted Gravity Drainage

“…The steam volume of SAGD symmetry elements on conditions that production factor is different are shown in Figure 3. With the increasing of production factor in SAGD symmetry elements, the mass production of the bottom horizontal well is increased, which leads to that the action of inhibition and dragging of the bottom production well to the overlap of vapor front have been enhanced, as well as contribute to accelerate the connection of steam chamber above the horizontal injection well, increasing the steam sweep volume within the symmetry elements [24,25].…”

Cyclic Supercritical Multi-Thermal Fluid Stimulation Process: A Novel Improved-Oil-Recovery Technique for Offshore Heavy Oil Reservoir

“…As the supercritical multi-thermal fluid also contains a large amount of nitrogen and carbon dioxide, the existing research on conventional thermal recovery technology also has certain reference value. Previous studies have confirmed that the addition of N 2 , CO 2 and other non-condensable gases during the steam stimulation procedure can improve the steam stimulation recovery effect of heavy oil efficiently [15][16][17][18]. The results showed that, besides reducing viscosity by heating, multi-thermal fluid (MTF) also reduces viscosity by dissolving non-condensable gas (mainly CO 2 ) [19][20][21][22][23].…”

“…Considering this situation, Zhou et al [12] creatively combined supercritical water technology with heavy oil thermal recovery technology and proposed supercritical multicomponent thermal fluid (SMTF) technology; that is, supercritical water reacts with diesel oil, heavy oil or oily sewage to generate supercritical multi-thermal fluid for offshore heavy oil thermal recovery. The main components of supercritical multi-thermal fluid include Energies 2022, 15, 9189 2 of 20 supercritical water, nitrogen and carbon dioxide, which are characterized by large heat carrying capacity, strong solubility and good diffusion.…”

Effect of Water Vapor on Pore Structure, Surface Functional Groups, and Combustion Performance of Pyrolytic Semicoke

“…3 However, the water vapor generated during the quenching process will rise to the pyrolysis stage (as shown Figure 1 ). 4 With the pyrolysis temperature increasing, the volatile matter in the coal is quickly ruled out during the pyrolysis process with more pores being opened and the adsorption capacity of the coal char increased, 5 and the water vapor generated during quenching coke affects the change of pore structure. The coal semicoke carbon skeleton melts and collapses when the temperature is too high and part of the micropores are transformed into mesoporous pore and mesopores, which reduces the adsorption capacity and thereby affecting the combustion performance of semicoke.…”