Bottomhole acid treatment and scaling inhibition efficiency enhancement by means of powder oxyethylidenediphosphonic acid

Authors: I.G. Klyushin, N.V. Novikov, B.R. Gilmutdinov (RN Management OJSC Branch in Tyumen, PR&TDC, Upstream, RF, Tyumen), A.A. Ryazanov, N.V. Glebova (Samotlorneftegaz OJSC, RF, Nizhnevartovsk), R.T. Israfilov (Varyoganneftegaz OJSC, RF, Nizhnevartovsk)

Key words: salts dissolving efficiency enhancement, acid penetration into the formation depth increase, dissolving and prevention of secondary precipitation, acid treatment efficiency enhancement, salt deposits inhibiting.

To enhance acid treatment efficiency in saline well stock wells it has been suggested to add powder oxyethylidenediphosphonic acid to fluid solutions. Laboratory tests showed that this results in calcite dissolving and acid penetrating into the formation rock capacities efficiency enhancement and also it effects in dissolving and prevention of secondary precipitation of iron hydroxide sedimentation. Acid solutions tests with addition of the oxyethylidenediphosphonic acid in field conditions showed high efficiency of these treatments for scaling inhibition after putting wells back on production. Some wells were indicated to show efficient acid treatment. Achieved productivity index ration was also preserved for a longer period of time.