高矿化度下弱凝胶体系调剖性能研究

通过单因素实验和正交实验考察了聚合物浓度、交联剂浓度、稳定剂浓度及氯化铬/乳酸摩尔比对凝胶性能的影响,研制了一种适用于高矿化度低渗透裂缝性油藏的弱凝胶体系配方,并对弱凝胶体系的驱油效果进行了研究。实验结果表明,在实验温度32℃、地层水矿化度为29 500 mg/L条件下,优选出弱凝胶体系配方为:聚合物质量浓度2 000 mg/L,稳定剂质量浓度800 mg/L,交联剂质量浓度200 mg/L,三氯化铬/乳酸的摩尔比为1∶8;弱凝胶体系注入量越大(0.3～0.6 PV),低渗层采收率提高值越高,对于层间差异大的油层,或对于存在高渗透率的油层,加大注入凝胶量才能调整流量分配,注凝胶后的注入水更多的进入低渗透油层驱油,采收率提高值大于15%。

Research on profile control effect of delayed crosslinking weak gel system in the condition of high salinity

Through single factor experiment and orthogonal experiment of gel system,the influences of polymer concentration,crosslinking agent concentration and ratio,stabilizer concentration and temperature on gel properties were studied.A weak gel system suitable for low permeability fractured reservoirs with high salinity was developed.And the plugging ability and oil displacement effect were studied.The results showed that under the conditions of 32℃and salinity 29 500 mg/L,a weak gel formulation of polymer concentration 2 000 mg/L,stabilizer concentration 800 mg/L,crosslinking agent concentration 200 mg/L,and chromium trichloride and lactic acid mole ratio 1∶8 was preferred.The shearing,salt resistance and good plugging effect of this weak gel system were showed up.The greater the injection amount(0.3-0.6 PV)of the weak gel was,the higher enhanced oil recovery value in the low permeability tube was.For layers with big difference or existing high permeability,the flow distribution could be adjusted by increasing the injection amount(0.6 PV).In addition,the enhanced oil recovery value was greater than 15%.