Research on compound plugging removal technology and its application in Xinmu oilfield of Jilin

Most fault-block reservoirs in Xinmu oilfield belong to heterogeneous sandstone in characters which has low permeability , and reservoir pollution is a common phenomenon in this area. Acidizing deplugging in oil wells has become one of the major measures to improve production efficiency in the field. A compound deplug- ging technology in high efficiency low corrosion is developed for this kind of low permeability sandstone reser- voir. On the basis of profoundly understanding of the reservoir's physical properties and sensitivity , along with comprehensive analysis of the cause for jams in oil wells , a series of experiments are carried out in order to in- vestigate the dissolution reaction among samples and deplugging inhibitor , sample dissolving speed , formation fluid compatibility , reduction of secondary pollution , etc. Considered reservoir condition in nearby wells the op- timized compositional deplugging liquid formula is selected for this reservoir. It is featured by reducing the de- plugging reaction speed , extending solution for processing radius , preventing secondary damage in dissolution processing , and removing plug pollution effectively. To implement this high efficiency low corrosion deplugging measure based on reservoir condition in the borehole and nearby wells , a relatively better result of deplugging and production increasing is achieved , which enriches the measures to increase production in Xinmu oilfield , and this method can be applied to other similar oilfields for the purpose of maintaining the crude oil production