US 12,331,623 B1
Methods for diagnosing control effectiveness of fracture heights in hydraulic fracturing by combining monitoring pressure signals
Xiyu Chen, Chengdu (CN); Manqing Qian, Chengdu (CN); Yongming Li, Chengdu (CN); Jinzhou Zhao, Chengdu (CN); Xia Dan, Chengdu (CN); Linyao Yu, Chengdu (CN); and Zhibo Yu, Chengdu (CN)
Assigned to SOUTHWEST PETROLEUM UNIVERSITY, Chengdu (CN)
Filed by SOUTHWEST PETROLEUM UNIVERSITY, Sichuan (CN)
Filed on Feb. 12, 2025, as Appl. No. 19/051,212.
Claims priority of application No. 202411165040.1 (CN), filed on Aug. 23, 2024.
Int. Cl. E21B 43/26 (2006.01); E21B 49/00 (2006.01)
CPC E21B 43/26 (2013.01) [E21B 49/00 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for diagnosing control effectiveness of a fracture height in hydraulic fracturing by combining monitoring a pressure signal, comprising:
S1: obtaining engineering data and geological data of a target oil and gas well, denoting a cumulative fracturing time as t, and setting a time step for simulation computation as Δt, setting a reference pressure pr in an initial state as 0 Pa, and a growth time tp of the fracture height in the initial state as 0 s;
S2: calculating a fracture slit fluid pressure pfrac at the cumulative fracturing time t and a double-logarithmic slope n of the fracture slit fluid pressure at the cumulative fracturing time, and calculating a bedding fracture pressure pe based on a bedding dip angle;
wherein the fracture slit fluid pressure pfrac at the cumulative fracturing time t is calculated by a following equation:

OG Complex Work Unit Math
where pfrac denotes the fracture slit fluid pressure at the cumulative fracturing time t in Pa; ps denotes a pressure inside a wellbore of a target fracturing section in Pa; ρ denotes a density of fracturing fluid in kg/m3; q denotes a displacement of fracturing fluid of a perforation cluster in m3/s; m denotes a perforation number of the perforation cluster, which is dimensionless; and dp denotes a perforation diameter of the perforation cluster in m;
the double-logarithmic slope n of the fracture slit fluid pressure at the cumulative fracturing time is calculated by a following equation:

OG Complex Work Unit Math
where n denotes the double-logarithmic slope of the fracture slit fluid pressure, which is dimensionless; pr denotes the reference pressure in Pa; and Δt denotes the time step s;
the bedding fracture pressure pe is calculated by a following equation:

OG Complex Work Unit Math
where pe denotes the bedding fracture pressure in Pa; σmin denotes a minimum horizontal principal stress in Pa; σh denotes a vertical stress in Pa; α denotes the bedding dip angle in rad; and Rt denotes a bedding tensile strength in Pa;
S3: determining whether the fracture height in hydraulic fracturing grows at the cumulative fracturing time t based on the fracture slit fluid pressure pfrac, the double-logarithmic slope n of the fracture slit fluid pressure, and the bedding fracture pressure pe:
in response to pfrac>pe and |n|<0.1, determining the fracture height in hydraulic fracturing not growing at the cumulative fracturing time t; and
in response to pfrac≤pe or |n|≥0.1, determining the fracture height in hydraulic fracturing growing at the cumulative fracturing time t, updating the growth time tp of the fracture height to tp+Δt, and updating the reference pressure pr to pfrac;
S4: determining whether a fracturing construction operation ends based on the cumulative fracturing time t and a total time of hydraulic fracturing Ta:
in response to t<Ta, determining the fracturing construction operation not ending, updating the cumulative fracturing time t to t+Δt, and repeating step S2 to step S4; and
in response to t≥Ta, determining the fracturing construction operation ending and proceeding to S5; and
S5: calculating a ratio G of the growth time tp of the fracture height to the total time of hydraulic fracturing Ta, and diagnosing the control effectiveness of the fracture height based on the ratio G, wherein the smaller the ratio G is, the better the control effectiveness of the fracture height is.