2. 渤海钻探第二固井分公司，天津300280;

3. 华北油田开发事业部，河北任丘062552;

4. 渤海钻探工程技术处，天津300450;

5. 华北油田储气库管理处，河北任丘062552;

6. 中海石油( 中国) 有限公司天津分公司，天津300452

2. The Second Well Cementation Branch of CNPC Bohai Drilling Engineering Company Limited，Tianjin 300280，China;

3. Development Department of Huabei Oilfield，Ｒenqiu 062552，Hebei，China;

4. Technique Department of CNPC Bohai Drilling Engineering Company Limited，Tianjin 300450，China;

5. Gas Storage Management Department of Huabei Oilfield，Ｒenqiu 062552，Hebei，China;

6. Tianjin Branch of CNOOC，Tianjin 300452，China

intervals，the productivity of the sandy conglomerate reservoir has been significantly descended． In this study，a weakly acidic surfactant is developed and applied to decrease the viscosity of oil and remove plugs out of reservoir．The weakly acid is used to dissolve part of the clay minerals and unclog the seepage channels． The pyrolysis and emulsification function of the surfactant can decrease the viscosity and thus improve the seepage capability of oil．The method was successfully applied in well treatment，through which the daily well production increased from 0. 38 m3 /d to 63. 91 m3 /d． The double targets of‘production increase and reservoir protection at the same time’have

been realized．

removing   Jilantai oilfield