Testing device and method for floating rate of floating agent for fracture height control
A testing device and method for floating rate of floating agent for fracture height control are provided. The test device includes a support frame, a glass tube vertically fixed on the support frame, a floating agent storage container, a control valve, and a liquid storage tank, wherein multiple circular holes are uniformly distributed along an axial direction of the glass tube, and multiple turbidimeters for measuring liquid turbidity are sequentially mounted on the circular holes. The liquid storage tank communicates with an inner cavity of an upper end of the glass tube through a pipeline, and the floating agent storage container is connected to an inner cavity of a lower end of the glass tube through a control valve. The present invention increases accuracy of measured floating rate of the floating agent, and provides reliable floating data of the floating agent for oil and gas reservoir reconstruction.
1. A testing method for floating rate of floating agent for fracture height control, comprising steps of:
step A: turning off a control valve A and a control valve B, loading a floating agent for fracture height control into a floating agent storage container, and injecting distilled water into a liquid storage tank;
step B: turning on the control valve B, filling a glass tube with the distilled water, and recording turbidity data z 10 , z 20 , z 30 , z 40 , and z 50 of five turbidimeters before test;
step C: turning on the control valve A so that the floating agent contacts the distilled water in the glass tube, initiating a floating process, and using a current time, at which the floating agent is contacting the distilled water in the glass tube, as an initial floating time to;
step D: recording the turbidity data of the five turbidimeters at intervals during the floating process, denoting a turbidity data of the n-th turbidimeter at the i-th time t i as z ni ;
step E: plotting a curve of turbidity over time monitored by each of the turbidimeters z nt =f(t), and determining a time t nf at which a turbidity value at each of the turbidimeters starts to change and a time t nl at which the turbidity value returns to a reference value after reaching a peak according to the curve;
step F: using following formula to calculate a floating rate of the floating agent according to time data t nf and t nl of each of the turbidimeters:
{
u
nf
=
D
n
t
nf
-
t
0
u
nl
=
D
n
t
nl
-
t
0
;
wherein u nf is a maximum floating rate of the floating agent calculated based on the data of the n-th turbidimeter, in mm/s; u nl is a minimum floating rate of the floating agent calculated based on the data of the n-th turbidimeter, in mm/s; D n is a floating distance of the floating agent corresponding to the n-th turbidimeter, in mm; t 0 is an initial time when the floating agent floats during test, in s; t nf is a time when the turbidity value at the n-th turbidimeter starts to change from the reference value, in s; t nl is a time when the turbidity value at the n-th turbidimeter returns to the reference value after reaching the peak, in s;
step G: averaging the maximum floating rate and the minimum floating rate of the floating agent calculated based on each turbidimeter data to obtain an average maximum floating rate u max and an average minimum floating rate u min of the floating agent:
u
max
=
(
∑
n
=
1
N
u
n
f
)
/
N
;
u
min
=
(
∑
n
=
1
N
u
n
l
)
/
N
;
wherein N is a number of the turbidimeters, dimensionless; u nf is the maximum floating rate of the floating agent calculated based on the data of the n-th turbidimeter, in mm/s; u nl is the minimum floating rate of the floating agent calculated based on the data of the n-th turbidimeter, in mm/s; u max is the average maximum floating rate, in mm/s; u min is the average minimum floating rate, in mm/s.
2. The testing method for floating rate of floating agent for fracture height control of claim 1 , wherein the floating agent for fracture height control has a particle size of 70-200 mesh, and a bulk density of 0.33 g/cm 3 .