苏里格低品质储层用低伤害胍胶压裂液开发与应用

Development and Application of Low-Damage Guar Gum Fracturing Fluid for Low-Quality Reservoirs in Sulige Gas Field

随着苏里格优质储层不断动用,储层劣质化趋势明显;常规压裂液对储层的伤害越来越大,难以满足低品质储层高效开发的需求。针对上述问题,采用硼酸、多元醇、多胺等制备出长链多头极性交联剂,可以提供更多的交联位点,有效降低胍胶交联质量分数。配合使用多元助排剂、纳米修复剂,优化压裂液配方,开发出了低伤害胍胶压裂液。该压裂液具有低残渣、低伤害、低表面张力、防水锁、易返排等优点。试验结果表明,低伤害胍胶压裂液的交联时间在40~90 s范围内可调,耐温可达120℃,悬砂能力与常规胍胶压裂液接近,破胶时间在30~150 min范围内可调,破胶液表面张力低于25 mN/m,残渣含量约为200 mg/L,岩心伤害率20%左右。该压裂液已在长庆苏里格推广,应用效果显著,平均返排率提高7.4%,平均测试产量提高8.3%,表现出对苏里格低品质储层良好的适应性和低伤害性。

As the high-quality reservoirs in the Sulige gas field are produced,inferior reservoirs begin to be developed.Conventional fracturing fluids are causing increasing damage to the reservoirs,making them no longer applicable to efficient development of low-quality reservoirs.In order to solve this problem,boric acid,polyol and polyamine were used to prepare long-chain multiple polar crosslinker,which provides more crosslinking sites and effectively reduces the crosslinking concentration of guar gum.With the help of complex cleanup additive and nanorepair agent,the fracturing fluid formula was optimized,and a low-damage guar gum fracturing fluid was developed.This fracturing fluid has the advantages of low residue,low damage,low surface tension,anti-water-lock and easy backflow.Experimental results show that the crosslinking time of the low-damage guar gum fracturing fluid is adjustable from 40 s to 90 s,with a temperature resistance of up to 120℃.The proppant carrying capacity is similar to that of conventional guar gum fracturing fluid,and the breaking time is adjustable from 30 min to 150 min.The surface tension of the viscosity breaking fluid is less than 25 mN/m,the residual content is about 200 mg/L,and the core damage rate is about 20%.This fracturing fluid has been sucessfully applied in the Sulige gas field,with the average test production increased by 8.3%and the average backflow rate increased by 7.4%,exhibiting good adaptability and low damage to low-quality reservoirs in the Sulige gas field.