| Low permeability reservoir with higher sensitive minerals shows the characteristics of strong water sensitivity. If injected water is not compatible with formation fluid and reservoir, reservoir permeability will be damaged. In order to protect the reservoir, the field test that injected water with concentration of 1.0% clay stabilizer XA-1 could adapt development demands of water sensitivity reservoir, but the development cost has increased monotonically. In order to make best use of the residue of clay stabilizer XA-1 in recycled injection water and decrease dose, the research of optimization scheme on adding clay stabilizer in recycled injection water was carried out. The main research contents and conclusions of this paper are as follows:Studied on the effective components of clay stabilizer XA-1 and determined the mass fraction, studied on building a method to determine the content of effective components of residual clay stabilizer XA-1 in injection water, which was fast and accurate. The content of residual clay stabilizer XA-1 in different wells and injection water of joint station was detected by established method. The results showed that the effective component of clay stabilizer XA-1 was XCH by Thin Layer Chromatography. The color could not be observed on thin layer plate when the concentration of clay stabilizer XA-1 was lower than 1.0% and the concentration of XCH lower than 0.4%.The residues of clay stabilizer XA-1 in injection water could not be determined by Thin Layer Chromatography. The mass fraction of the effective components of clay stabilizer XA-1 XCH was 43.09% by the Method of Mohr. Ion Chromatography was built to analyze the residual XCH in injection water according to the structure and properties of XCH, which had good linear relation with 0.999, high sensitivity, the recovery was 96.3%~105%, RSD was less than 3%, low detection limit, high precision and accuracy. The residual XCH of 13 wells of test block with different moisture content and injection water of joint station was detected by Ion Chromatography, and the results showed that the content of residual clay stabilizer XA-1 in injection water of joint station was about 0.1%, the content in produced water from other wells was about 0.1%.Analysis and measurement had been made on ion content of Na+,K+,Ca2+,Mg2+,Cl- and SO42- in the source water and the injection water of joint station by Ion Chromatography, the content of HCO3-and CO32- by total dissolved inorganic carbon analyzer. The results showed that the salinity of source water was 1475mg/L less than the salinity of formation water, and the salinity of the injection water of joint station was 1020mg/L less than the salinity of formation water. Because the salinity had larger difference between injection water, source water and formation water, and the salinity of injection water was higher than the salinity of source water about 455mg/L, measures must be taken on the injection water to prevent reservoir permeability damage because of water sensitivity and salt sensitivity.The laboratory tests were carried out by the built analysis, which consist of the compatibility experiment, the rate of anti-swelling experiment, the rate of fragmentation of cuttings experiment and the core flow experiment, to determine the feasibility of reducing the addition amount of clay stabilizer XA-1 and propose reasonable suggestions according to the experimental results. The results showed that the injection water added clay stabilizer XA-1 had good compatibility with the formation water and reservoir. The rate of anti-swelling was above 87% when the injection water was added clay stabilizer XA-1 of 0.9% .The clay stabilizer XA-1 of 0.9% in injection water had basically no dispersing effect on cuttings in reservoir. The damage rate on reservoir was lower than 25% when 0.9% clay stabilizer XA-1 was added into the injection water, which was acceptable from the point of view of reservoir protection.
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