摘要 |
A process is proposed for blocking underground formations in the extraction of fossil oil and/or gas, a first step involving introducing water-absorbing particles into liquid-bearing and porous rock formations, said particles being water-swellable, crosslinked and water-insoluble polymers, said particles in the water-bearing rock formation finally preventing liquid flow through the rock layers by water absorption. This process is characterized in that the absorbing particles comprise a superabsorbent polymer with anionic and/or cationic properties and a retarded swelling action. This process, which can also be carried out in saline formation waters, is notable in that the swelling of the superabsorbents used begins no earlier than after five minutes and in that the superabsorbents are obtainable by four proposed process variants and any combination thereof. This process, which does not need a carrier liquid, is notable for its simplicity and especially the controllable retardation of the swelling action under the specific conditions of underground rock formations.
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