Optimization of Multiple Component Thermal Fluid Huff and Puff Technology for Horizontal Wells in Shallow Extra Heavy Oil Reservoir

Abstract

AbstractShallow extra heavy oil reservoir is mainly developed by cold production with horizontal well in Venezuela. The crude oil with high relative density, high asphaltene content, high heavy metal content, a certain degree of dissolved gas and relatively low viscosity is the unique resource in this area. At present, this kind of long horizontal section with cold production has been widely implemented, but the oil recovery is low. There are high uncertainties in characterization of injection parameters such as well spacing and injection volume. Compared with the well spacing of cold production and conventional steam huff and puff, the multi-component thermal fluid (MCTF) huff and puff has a certain range of sweeping. When the well spacing is too large, there will be areas where heat cannot reach, and it is difficult to recover the heavy oil in this area. If the well spacing is too small, the investment cost will be too large to reach the economic plan, and the gas channeling between wells may be formed prematurely due to the rapid diffusion speed of injected non-condensate gas, which affects the oil recovery. The reasonable well spacing of MCTF huff and puff is studied to ensure the oil recovery. According to the field experience and analysis, the injection volume has a significant influence on the development effect of MCTF technology. Based on the study of MCTF stimulation mechanism, numerical models of different reservoir types are established, and optimization research of injection volume of different well spacing is carried out, as to achieve economic and effective development effect.In this paper, when the well spacing is 200 m, the development effect performs better. Taking the cumulative oil increment and cumulative oil-MCTF ratio as the objective function, the optimization result of injection strength of multi-component thermal fluid in different types of reservoirs with 200 m well spacing is 10 ton/m, 7 ton/m and 6 ton/m respectively based on the numerical simulation method.