Modified Fracture Mechanics Approach for Hydraulic Fracturing Stress Measurements

Table 3

Summary of the experimental stress measurement data and the results based on equations (2) and (3).

No.	Rock type	HF parameters (MPa)				Calculated stress (MPa)		Applied stress (MPa)		Relative error (%)
		HF-JG-2	Granite	14.42	8.40	5.16	6.02	7.08	5.16	9.83	4.86	27.98	6.24
HF-JG-5	Granite	18.73	8.77	7.63	9.96	14.12	7.63	14.53	7.33	2.82	4.11
HF-HS-1	Sandstone	13.01	7.75	6.16	5.31	10.73	6.16	9.76	6.11	9.89	0.79
HF-HS-3	Sandstone	14.56	9.79	7.41	4.77	12.44	7.41	9.95	6.22	25.63	0.80
HF-HS-4	Sandstone	10.61	7.69	5.34	2.92	8.33	5.34	9.90	7.47	15.35	8.11
HF-HS-5	Sandstone	9.70	7.83	5.72	1.87	9.33	5.72	9.84	4.94	5.88	4.28

Notes: —breakdown pressure; —fracture reopening pressure; —instantaneous shut-in pressure; —tensile strength; —minimum horizontal principal stress; —maximum horizontal principal stress. Here, and .