Research on improvement of water-injection technology in low porosity and low permeability reservoir and its application

The oil-bearing formation of Yan 2 block of Benbutu oil field is Jurassic Sangong River group, which is low porosity and low permeability. Those reservoirs generally confronted with water-injection and oil production difficulties. Based on formation characterization and researches of its influence on water absorbing capacity of injection wells, the reasonable injection pressure was determined by water absorbing capacity research of this block. The injection allocation requirement and injection and production balance was maintained in the northwest injection wells by research on the adaptability of water-injection under the influence of well pattern, well spacing and the improvements of injection pattern. The acidizing treatment and the parametric design was optimized by conducting the in-house experiments, and its field applications have obvious depressurization and injection augment effects. The standard of water quality for oilfield injection was established and water quality treatment technology was proved suitable to this block. ZXJC30-Ⅳ well washing truck was applied for water-injection systems with no returning pipelines, and well washing problems in injection wells and its applications for other matching technologies were also effectively solved. By application of the researching results of this paper, Yan 2 block of Benbutu oil field implemented the favorable water-injection production and provided valuable experiences to other similar blocks and oil fields.