Oil well treating method and composition

A method of treating a clay-containing earth formation for the purpose of preventing or at least reducing the swelling, migration and/or dispersion of said clay to thereby stabilize said formation, said method being comprised of contacting said clay in said formation with an effective amount of an organic polycationic polymer dispersed or dissolved in a carrier fluid, said contacting being for a time sufficient for said organic polycationic polymer to replace clay cations to thereby transform said clay to a more stable form wherein said organic polycationic polymer contains repeating monomer units selected from the group consisting of:

• ##STR23## wherein R.sub.1 is a divalent normal or branched chain alkylene group containing 2 to 40 carbon atoms, R.sub.2 and R.sub.3 can be the same or different and are normal or branched chain alkyl groups containing 1 to 6 carbon atoms;
• R.sub.4 and R.sub.6 can be the same or different and are selected from divalent organic aliphatic groups containing 2 to 40 carbon atoms, R.sub.5 and R.sub.7 can be the same or different and are selected from monovalent organic aliphatic groups containing 1 to 6 carbon atoms;
• R.sub.8, R.sub.10 and R.sub.11 can be the same or different and are selected from monovalent alkyl alkenyl and aryl groups containing 1 to 6 carbon atoms, R.sub.9 is a divalent organic aliphatic group containing 2 to 40 carbon atoms;
• R.sub.13 is a divalent organic aliphatic group containing 2 to 40 carbon atoms which together with the phosphorous atom in the monomer unit forms a heterocyclic ring,
• R.sub.12 and R.sub.14 can be the same or different and are selected from monovalent organic aliphatic groups containing 1 to 6 carbon atoms;
• X is an anion selected from halides, nitrate, sulfate, methosulfate, bisulfate and carbonate;
• n is an integer equal to the number of monomer units in said polymer required to produce a molecular weight in the range of from about 1,000 to 3,000,000;
• and
• m is an integer equal to the number of said anions required to maintain electrical neutrality;
• and further wherein the ratio of the total number of said phosphorous atoms in said polymer to the total number of carbon atoms in said polymer is in the range of about 1 to 2 to about 1 to 36.