Methods of minimizing fines migration in subterranean formations
AssigneeHalliburton Company
InventorJohn K. Borchardt
Life of this patent
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Abstract
A method of treating a permeable structure for the purpose of stabilizing fines in the structure using organic copolymers containing N-vinylpyrrolidone in the copolymer repeat unit.
Claims19
A method of preventing or reducing the migration of fines in a permeable subterranean formation comprising:
- contacting said fines in said permeable subterranean formation with an effective amount of an organic copolymer having recurring structural monomer units formed in a random fashion of the formula:
- ##STR4## wherein R.sup.1 and R.sup.4 are independently selected from the group consisting of an alkylene group having 1 to about 4 carbon atoms;
- R.sup.2, R.sup.3, R.sup.5, R.sup.6, and R.sup.7 are independently selected from the group consisting of methyl and ethyl;
- A is selected from the group consisting of chloride, bromide, iodide, hydroxide, and methyl sulfate;
- s is an integer equal to the number of said anions required to maintain electronic neutrality;
- x, y, and z are integers, the sum of which equals the total number of monomer units in the copolymer required to give a molecular weight in the range of from about 100,000 to about 1,500,000;
- and
- monomer unit I is present in the range of from about 80 to about 98 percent by weight of the copolymer;
- monomer unit II is present in the range of from about 2 to about 20 percent by weight of the copolymer;
- and,
- monomer unit III is present in the range of from about 0 to about 20 percent by weight of the copolymer.
A method of treating an earthen formation comprising fines to reduce loss of permeability in said formation because of the migration of said fines comprising:
- contacting said formation with an effective amount of an organic polycationic copolymer having recurring structural monomer units formed in a random fashion of the formula:
- ##STR5## wherein R.sup.1 and R.sup.4 are independently selected from the group consisting of an alkylene group having 1 to about 4 carbon atoms;
- R.sup.2, R.sup.3, R.sup.5, R.sup.6, and R.sup.7 are independently selected from the group consisting of methyl and ethyl;
- A is selected from the group consisting of chloride, bromide, iodide, hydroxide, and methyl sulfate;
- s is an integer equal to the number of said anions required to maintain electronic neutrality;
- x, y, and z are integers, the sum of which equals the total number of monomer units in the copolymer required to give a molecular weight in the range of from about 100,000 to about 1,500,000;
- and
- monomer unit I is present in the range of from about 80 to about 98 percent by weight of the copolymer;
- monomer unit II is present in the range of from about 2 to about 20 percent by weight of the copolymer;
- and,
- monomer unit III is present in the range of from about 0 to about 20 percent by weight of the copolymer.
A method of stabilizing migrating fines having a diameter of less than 10 microns in a subterranean formation comprising more than 5 percent by weight migrating fines and less than 2 percent by weight swelling clays comprising:
- contacting the fines with an effective amount of an organic polycationic copolymer having a molecular weight of about 1,000,000 and having recurring structural monomer units formed in a random fashion of the formula:
- ##STR6## wherein monomer unit I is present in an amount of about 80 percent by weight of the copolymer;
- monomer unit II is present in an amount of about 20 percent by weight of the copolymer.
Dependencies are inferred from the claim text.