苏里格气田压裂液返排液重复利用的可行性

Study on Reuse of Fracturing Flowback Fluids in Sulige Gasfield

针对目前存在的压裂液返排液重复配液难的问题,对苏里格气田不同区块及不同压裂液体系返排液组分进行了系统分析,同时分别采用单因素及正交试验对影响压裂液返排液重复配液性能的因素进行了深入研究。研究发现,压裂液在返排过程中从地层携带出的大量金属离子,尤其是一些高价金属阳离子对返排液的重复配液性能有显著影响,其中返排液中的Ca^2+、Mg^2+和Fe^2+对配液性能影响最大,针对0.4%的EM50和胍胶体系,实验测得这3种离子满足返排液重复配液的上限值分别为250、150、150 mg/L和275、250及200 mg/L。另外,返排液中高含量的Cl-及矿化度等因素也会影响返排液的重复配液性能。通过向返排液中加入一定浓度的络合剂或沉淀剂,再辅以清水稀释的方式可有效解决由于金属离子或矿化度太高导致的返排液重复配液问题。

Aiming at the difficulty in repeated liquid dispensing with fracturing flowback fluids in present,the composition of the fracturing flowback fluids in different blocks of Sulige gasfield were systematically analyzed.At the same time,the single factor and orthogonal test were used to study the factors affecting the performance of fracturing fluid flowback.The results showed that great quantity of metal cations was carried out from the formation during the process of fracturing fluid flowback,which had a significant effect on the performance of repeated liquid dispensing.Eespecially,Ca2+,Mg2+and Fe2+had the greatest influence on the performance of liquid dispensing.For the 0.4%EM50 and guar colloid system,the upper limit values of the three ions satisfying the repeated liquid dispensing were 250,150,150 mg/L,and 275,250 and 200 mg/L,respectively.In addition,the high concentrarion of Cl-and salinity in the flowback fluids also affect the performance of the liquid dispensing.By adding a certain concentration of complexing agent or precipitating agent to the flowback fluids and then diluting with clear water,the problem of repeated liquid dispensing caused by metal ions or high salinity of the flowback fluids can be effectively solved.