压裂液破胶液对低渗储层伤害机理研究

DAMAGE MECHANISM OF FRACTURING AND GEL BREAKING LIQUID ON LOW PERMEABILITY RESERVOIRS

通过2种压裂液破胶液的岩心伤害、胶团粒径、分子质量、吸附性能等评价,研究了压裂液破胶液对低渗储层伤害的机理。实验结果表明:胍胶压裂液破胶液在未切除和切除10 mm后的岩心损害率分别为27.3%和4.5%,并在岩心端面观察到大量固相残留物;胍胶压裂液破胶液胶团粒径较大,难以进入岩心深部,伤害主要由岩心端面的滤饼引起。聚合物压裂液破胶液在未切除和切除10 mm后的岩心损害率分别为22.2%和15%,在岩心端面和深部均观察到固相残留物;聚合物压裂液破胶液胶团平均粒径较小,易进入岩心深部,在孔喉处吸附滞留,造成低渗储层深部伤害。

The mechanism of fracturing fluid gel breaker damage to low permeability reservoirs is studied by evaluating the core damage,gel particle size,molecular weight,and adsorption performance of two types of fracturing fluid.The experimental results showed that the core damage of guar gum fracturing fluid were 27.3%and 4.5%,respectively,before and after 10 mm removal.A large amount of solid residue was observed at the end face of the core.The molecular weight and particle size of guar gum fracturing fluid after gel breaking are relatively large,making it difficult to enter the deep part of the reservoir through the pore throat,forming filter cakes at the end face of the core and causing permeability damage.The damage of polymer fracturing fluid before and after 10 mm removal were 22.2%and 15%,respectively.Polymer solid residue was observed at both the end face and deep part of the core.After the fracture of polymer fracturing fluid,its molecular weight and average particle size are relatively small,making it easy to enter the deep part of the core and adsorb and retain at the pore throat,causing deep damage to low-permeability reservoirs.