| 摘要 |
Method of hydraulic fracturing oil and or gas wells to create a layered proppant pack structure alongside the faces of the fracture to prevent formation fines (10) to damage the fracture conductivity over time characterized in that it comprises several distinct steps:
i) Creating a hydraulic fracture (11) and transporting into the so opened fracture a "fine grained proppant" (5) (equally called "fine proppant" or "fine grained proppant" or "support proppant")
ii) Shutting-in the well to let the fracture close and the confinement stress of the reservoir to be re-established so as to compress the fine proppant against the walls of the fracture and resulting in a strong adhesion of the fine grained proppant against the walls of the fracture via mechanical and/or chemical mechanisms.
iii) Re-opening the same hydraulic fracture using a conventional fracturing technique to place a "larger or much larger proppant" (30) (equally called "coarse proppant" or "conductive proppant") in the middle of the fracture width and therefore between the layers of the fine proppant remaining in place against the walls of the fracture because of the strong interactions previously established during the shut-in, and acting as a "support" for the larger proppant, the said fine "support" proppant allowing the said larger proppant to ensure and retain a high conductivity for a long period of time.
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