注聚合物井堵塞机理分析及解堵剂研究

Blockage mechanism and blockage reducer for polymer-injection well

对大庆油田注聚合物井堵塞物进行了无机化学分析、有机化学分析、硫、铁和微生物对堵塞的影响实验及不同渗透率的岩心切片分析,认为堵塞物的主要成分是含钙镁离子和铁离子的不溶解物质以及黏土、出砂造成的核,聚合物大分子缠绕在核的周围,形成胶状的复合极团,由于其主要的尺寸与实际地层的孔喉不配合,造成堵塞。不同渗透率岩心的堵塞分析表明,相同的聚合物溶液对渗透率不同的地层堵塞程度不同,渗透率越低,岩心中黏土含量越高,黏土矿物电性特征将导致更多的聚合物被吸附在黏土矿物表面,无机堵塞物引起的堵塞越严重。对于渗透率较高的岩心,出砂引起的堵塞比低渗透储集层严重得多。针对注聚井堵塞机理,研制了3种解堵剂,评价实验结果,认为配方A效果最好,配方B次之,配方C效果一般。

Blockage material in polymer injection well in Daqing Oilfield is analyzed by inorganic and organic chemical methods, experiments were conducted to demonstrate the effect of sulfide. ferrum and microorganism on blockage, and slabbed core analyses of different permeability were carried out. The research shows that the main components of the blockage arc infusible substance containing calcium and magnesium ions, clay and nucleus formed in sand production. Large polymer molecules wrap around nucleus and form gelatinous complex groups, whose main scale does not match with the throats of actual formation and causes formation blockage. Blockage analyses of various permeability cores show that blockage degrees of different permeability formations are different for the same polymer solution. The lower the core permeability is, the higher is the clay content in the core, and the more polymer is adsorbed on the surface of clay mineral because of electrical character, thus the more serious blockage is caused by inorganic stem. For the core of higher permeability, blockage caused by inorganic stem in sand production is much more serious than that of low permeability formation. In accordance with the blockage mechanism, 3 types of blockage reducers were developed, evaluation of the experiment results show that receipt A is the best, B is medium and C is common.