Method of consolidating subterranean formations using cationic and anionic and/or non-ionic polymers

A method of consolidating a subterranean formation which comprises particles, wherein said particles are the same as those which form the structure of the formation and/or fines present within the structure of the formation, said method comprising:

• (i) selecting a subterranean formation in need of consolidation;
• (ii) contacting said particles with a cationic polymer;
• and then
• (iii) contacting said particles with an anionic polymer and/or a non-ionic polymer to agglomerate said particles and thereby consolidate said formation, wherein said agglomeration increases the uniformity of the size of said particles, the agglomerated particles comprise an average diameter of 250-2500 pm, and
• wherein said cationic polymer is formed from monomers of formula (I):
• wherein
• R1 is H, CH3;
• R2 is COY, C6-12 aryl or C3-12 heteroaryl;
• Y is OR or NR2;
• and
• each R is independently selected from H and C1-6 alkyl;
• and/or
• said cationic polymer is formed from monomers of formula (II):
• wherein R1 is H or CH3 and A is C3-12 heteroaryl group;
• and/or
• wherein said cationic polymer is formed from monomers of formula (III):
• wherein
• R1 is H or CH3;
• Y is OR or NR2;
• and
• each R is independently selected from H and C1-6 alkyl;
• and/or
• wherein said cationic polymer is formed from monomers of formula (IV):
• wherein
• R1 is H or CH3;
• Yi is O or NH;
• m is an integer from 1 to 6, preferably 2 or 3;
• each R2 is independently H or C1-6 alkyl, preferably each R2 is methyl;
• and
• X— is a counter anion.