The Research Of Acid Treatment Technology For Low Permeability And High Water Sensitivity Sand Formation

Acid treatment is an important measure which stimulates the production in the oil well. Acid treatment is a kind of treatment technique by injecting acid liquid into oil well, making the most part of acid liquid filter into formation along radial direction, thus, to enlarge the interstitial space under the effect of the acid liquid, and dissolve the grain block in the space,and eliminate the bad influence on the permeability of the stratum nearby well bore, and restore or raise the permeability of the stratum nearby well bore, to attain the result that stimulate production. This technique has gotten extensive application in the oil field. Acid treatment of sandstone stratum is a challenging task, because it includes several chemical and physical interactions between acid and formation, some of these reactions may result in stratum being damaged. Considering of the shortcoming of clay damaging badly in low permeable formation and the secondary precipitation of normal mud acid, this paper studied a new kind of acid liquid. By a mass of tests, the chemical reagents were selected, in the end, the formulation of acid liquid was determined. This type of acid liquid is suitable for high water sensitivity and low permeability stratum. This type of acid liquid may decreases the damage degree to the formation which contains clay, and may decreases secondary precipitation, and may restore or raise permeability of the stratum nearby well bore, at the same time, may achieve the purpose that stimulate oil production of the oil wells and injection rate of water injection wells.