| 摘要 |
<p>A method of improving oil or gas well productivity from a well penetrating a formation in an oil or gas reservoir, by forming a load fluid by obtaining a hydrocarbon fluid containing a known percentage of aromatics and adding an amount of CO2 to the hydrocarbon fluid that is determined according to a predetermined miscibility relationship between the CO2 and the hydrocarbon fluid that establishes the amount of CO2 required to form a bank of CO2 ahead of the load fluid in the formation. The load fluid is applied to the well at a pressure such that CO2 in load fluid within the well bore remains in solution and CO2 in load fluid within the formation leaks off the load fluid into the formation and forms a bank of CO2 ahead of the load fluid. The surface pressure is released from the load fluid and the load fluid flows back out of the well. The miscibility relationship between CO2 and hydrocarbon based load fluids depends on the aromatic content of the load fluid. For high pressure wells, since the amount of CO2 required becomes excessive, it is preferable to use a load fluid that requires a smaller amount of CO2 to form a bank in front of the load fluid for a given amount of the load fluid, hence one that has a lower amount of aromatics. The aromatic content of the hydrocarbon fluid is selected according to the pressure required for the well treatment.</p> |
