WEIGHTED BUFFER LIQUID Russian patent published in 2000 - IPC

FIELD: attachment of oil and gas wells, more particularly grouting of casing strings. SUBSTANCE: weighted buffer liquid comprises clay powder, polyacrylamide, carboxymethyl cellulose weighting compound, e.g. iron ore concentrated and water, ratios of components being as follows: wt.%: clay powder, 1.92-2.38; polyacrylamide, 0.02-0.03; carboxymethyl cellulose, 0.10- 0.13; iron ore concentrate, 52.29-61.47; and water 36.49-45.17. EFFECT: lower water loss, higher sedimentation stability, formation of structure capable of carrying weighting compound, elimination of coagulation of contact zones between drilling mud and grouting mortar in zone of abnormally high seam pressure. 3 tbl