Study on Fluid-Rock Interaction and Reuse of Flowback Fluid for Gel Fracturing in Desert Area

Table 4

Gelation and cross-linking tests for removing different divalent metal ions.

Formulations	Concentrations of divalent metal ions (ppm)	Concentrations of EDTA or GL-47S (ppm)	Results
IT-6; (CaCl2 with EDTA)	200	1000	Normal cross-linking (PH = 8)
	500	2000
	1000	4000
IT-7; (CaCl2 with Gl-47S)	200	1000	Normal cross-linking (PH = 9)
	500	2000
	1000	4000
IT-8; (MgCl2 with EDTA)	200	1000	Normal cross-linking (PH = 8)
	500	2000
	1000	4000
IT-9; (MgCl2 with Gl-47S)	200	1000	Normal cross-linking (PH = 9)
	500	2000
	1000	4000
IT-10; (FeCl2 with EDTA)	40	1000	Normal cross-linking (PH = 8)
	400	>2000
	600
IT-11; (FeCl2 with Gl-47S)	40	1000	Normal cross-linking (PH = 9)
	400	>2000
	600