It is surprising to find that, regardless the initial molecular weight of the polymer injected, the molecular weight of the polymer in the produced water is low, around 4 to 10 million. The questions that leap to our minds are:
–What is the viscosity of the brine inside the reservoir ?
–What is the efficiency of the motor fluid ?
–Which are the parameters affecting this efficiency ?
–How can the polymer flood be optimized ?
Average molecular weight:
Polyacrylamides are formed of very long chain of polymers, several million Daltons, and the average molecular weight does not represent the length of the chain. A polymer is a mixture of long and short chains. In fact, even with very different average MW, a part of the molecules are the same.
Chemical degradation:
The mechanism of chemical degradation is the formation of free radicals that cut the chain
These free radicals are formed by the reaction of an oxidizer with a reducer (redox)
The high molecular weight chains are more sensitive to chemical degradation, especially those above 15 million MW
The best polyacrylamide stability is found in a reducing media
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دانلود پاورپوینت Optimizing Molecular Weight in Polymer Flood