Research on Heavy Oil Thermal Recovery by CO₂ Steam Flooding with Help of Combination of Borehole-Surface Electric Potential and Cross-Borehole Electric Potential

Abstract

With an increasing tendency towards more demand for energy resources, the supply of energy as a focus of global strategy is attracting more and more attention from the world. However, on the one hand, conventional hydrocarbon resources are decreasing gradually, and therefore it is definitely an urgent task to search for renewable and replaceable resources at the present time. On the other hand, it has been proved that the total reserves of heavy oil are already up to 1105×108 tons around the world, which means that exploring heavy oil can be a beneficial supplement for alleviating the shortage of oil and gas. Moreover, it is noteworthy that because the heavy oil can be exploited by heated CO 2 , collecting and consuming CO 2 during the production process will help to relieve global warming.In this study, we take the feasibility of heavy oil recovery by CO 2 steam into consideration only from the viewpoint of geophysics. In the process of research, with the help of borehole-surface electric potential and cross-borehole electric potential, the entire procedures from heating heavy oil reservoir and optimizing the location of well to deciding the layer of perforation are exhibited completely. In the course of calculation, potential distributions corresponding to a point source of current are acquired by solving the Poisson equation using a direct and explicit finite difference technique for a lower half-space with 3-D distribution of conductivity. As for computation of a large sparse matrix, the technique of nonzero bandwidth storage and the Incomplete Cholesky Conjugate Gradient method are adopted. The consequences prove that with the assistance of crossborehole electric potential combining with borehole-surface electric potential, the project of heavy oil recovery by CO 2 steam is feasible and effective.

Molecular Simulation of CO2 Solubility and Its Effect on Octane Swelling

“…Experimental studies and reservoir simulations on CO 2 and hydrocarbon mixtures − were carried out to improve hydrocarbon recovery. Pressure/volume/temperature (PVT) studies and core flood experiments indicated that the important mechanism for hydrocarbon recovery by gas injection was mainly a hydrocarbon volume increase and viscosity reduction, and pure CO 2 appeared to be the best recovery agent. − Some authors have investigated the potential of carbonated (CO 2 -enriched) water injection for improving recovery from hydrocarbon reservoirs with the added benefit of safe storage of CO 2 by conducting high-pressure flow visualization, core flood experiments, and detailed compositional simulation at reservoir conditions. , In addition to time-consuming experimental methods and reservoir models, CO 2 -hydrocarbon solubility parameters have been obtained from correlations available in the literature. ,− Recently, the solubility and self-diffusion of carbon dioxide and hydrogen sulfide in linear polyethylene melts and brines were reported. , Attempts to understand the thermal behavior at hydrocarbon-solid surfaces have been made using molecular modeling by a number of authors. − There has been extensive research on the effect of CO 2 dissolution on hydrocarbon viscosity, and many correlations have been developed.…”

Insights into Enhanced Oil Recovery by Coupling Branched-Preformed Particle Gel and Viscosity Reducer Flooding in Ordinary Heavy Oil Reservoir

“…Heavy oil exploitation has a significant impact on the pattern of world oil production. However, heavy oil has the characteristics of high colloid and asphaltene content, high viscosity and density, and poor flow capacity, resulting in great difficulty and high production cost of recovering heavy oil [1][2][3][4]. For ordinary heavy oil reservoirs, due to adverse mobility ratio between water and oil, the fingering effect occurs and the oil recovery efficiency of conventional water flooding is low.…”

Insights into Enhanced Oil Recovery by Polymer-Viscosity Reducing Surfactant Combination Flooding in Conventional Heavy Oil Reservoir

“…Heavy oil resources as one of the most important unconventional resources are widely distributed in several countries such as China, Canada, and Venezuela. The viscosity of heavy oil typically ranges from 50 to 50000 mPa•s at reservoir temperature and pressure [1][2][3][4][5]. Water flooding is recognized as one of the most common secondary oil recovery techniques after primary production period, which has been widely applied for the recovery of light oil.…”