Study of Compositions for Selective Water Isolation in Gas Wells

A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottomhole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water. During injection, this composition shows selectivity and mostly penetrates water-saturated porous media. The study shows that the injection of such composition into porous media has a high water-insulating effect, reducing the water permeability of water-saturated porous media by 35 times with a degree of water isolation of 97%. Moreover, while injecting, it has selective action, mainly penetrating water-saturated media rather than gas-saturated media. As a result of injecting 0.91 to 0.99 pore volumes (pv) of the composition, the Qwater/Qgas ratio reaches 5.22 to 5.26, indicating high selectivity.

Propagation of Pore Pressure and Stress in Saturated Porous Media Based on a Darcy-Brinkman Formulation

Propagation of pore pressure and stress in water-saturated elastic porous media is theoretically investigated when considering the Darcy-Brinkman law. The wave mode, phase velocity, phase lag, damping factor, and characteristic frequency are found from the updated mathematic model. The Brinkman term describes the fluid viscous shear effects and importantly contributes to the dispersion relation and wave damping. The coincidence of the properties of Biot waves of the first and second kinds occurs at a characteristic frequency, which is remarkably influenced by the Brinkman term. A key finding is that, compared to the Darcy-Brinkman law, Darcy’s law overestimates the phase velocity, damping, and phase lag of the first wave, while underestimates the phase velocity, damping, and phase difference of the second wave. The introduction of the Darcy-Brinkman law yields an improved description of the damping of the compressional wave modes in saturated porous media.

A Study of Compositions Relevant to Selective Water Isolation in Gas Wells

A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottom hole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water. During injection, this composition shows selectivity and mostly penetrates water-saturated porous media. The study shows that the injection of such composition into porous media has a high water-insulating effect, reducing the water permeability of water-saturated porous media by 35 times with a degree of water isolation of 97%.Moreover, while injecting, it has selective action, mainly penetrating water-saturated media rather than gas saturated media. As a result of injecting 0.91 to 0.99 pore volumes (pv) of the composition, the Qwater/Qgas ratio reaches 5.22 to 5.26, indicating high selectivity.