Application Of Scale Inhibitor Squeeze Technique In Jiangsu Zhuang-2 Oilfield

Water flooding has become one of the most important exploitation methods. In the process of oil field development, particularly with increasing of water production, scale has become serious problems. Zhuang-2 Blocks belong to high calcium and low permeability reservoirs,When the fluid flows through the different areas of oil wells, with the pressure and temperature conditions changing, chemical balance is broken, when it exceeds the critical concentration of scale forming ion, it's easy to scale, and we find the scale exists in perforation, pump, valve, rod, oil tube and so on. Compared with other antiscale techniques, squeeze technique can prevent scaling from the area of near bottom,holewell bore to surface pipelines with simple operation. Meanwhile, the produced fluid contains a higher concentration of CO₂, S^2-, Cl^-, SO₄^2-, oil wells exist serious corrosion problems, we solve these problems by the study of the solid corrosion inhibitor technology. This research aims at developing combined techniques to handle the scale and corrosion in Zhuang-2 oil producers.In this paper,the reasons and affecting factors of scale were analyzed, and the trend of scale was predicted using the softwares OFISTP3.0 separately. In order to facilitate the application of inhibitor squeeze technique in JiangSu Oilfield, scale inhibitors have been selected based on laboratory experiments, including compatible tests, scale inhibition efficiency and MIC (minimum inhibitor concentration) experiments and dynamic adsorption experiments. Corrosion inhibitors were also selected based on the important corrosion factors in the field, especially the CO₂ corrosion. Convenient coupon weight was used in the evaluation of corrosion inhibitors. The effects of combined scale and corrosion inhibitors on scale and corrosion control were also studied. The results demonstrated that the SA1320 is best for scale control, and the combination of SA1320 and ECO-871GH1-2 is satisfactory for both scale and corrosion control. Based on the different situation of the target wells Zhuang 2-29,Zhuang 2-15 and Zhuang 2-19, we design different schemes(concluding ahead flood block, inhibitor liquid block and overflush liquid block); at last, after application in target wells with squeeze scale inhibitor SA1320 to the formation, keeping monitor the amount of produced liquid, inhibitor concentration in produced liquid, and analysis the effect of anti scale. And the solid corrosion control program is designed for the corrosion, combined scale inhibitor squeeze and solid corrosion inhibitor technique is efficient.