Weak
gel is a kind
of three-dimensional
cross-linking system with low polymer concentration and appropriate
cross-linking agents, dominated by intermolecular cross-linking, supplemented
by intramolecular cross-linking, and with a weak cross-linking degree.
In this paper, the microstructure and properties of the weak gel were
observed and evaluated under different conditions. Seepage behavior
experiments and parallel core displacement experiments were carried
out to evaluate profile control and flooding performance of the weak
gel. Under a certain polymer concentration, with the increase in cross-linker
concentration, the reticular structure of the weak gel becomes more
uniform and the strength of the weak gel was further enhanced. Weak
gel has more retention in porous media and greater strength. The profile
control and flooding performance of the weak gel are much better than
those of the polymer. A field test of weak-gel flooding was successfully
carried out in LD10-1 oilfield. Most of the production wells around
the weak gel injection wells responded after weak-gel injection and
the accumulative oil incremental oil production of the test area was
57.8 × 10
4
m
3
up to December 2018.
The aim of the present study was to evaluate the clinical effect of percutaneous vertebroplasty (PVP) in the treatment of old osteoporotic vertebral compression fracture (OVCF) pain.
A retrospective study was conducted on the clinical and imaging data of 31 patients with old OVCF treated by PVP from June 2010 to September 2011. Clinical efficacy was evaluated by the visual analog scale (VAS) scores, the oswestry disability index (ODI), the Cobb angle, and vertebral kyphotic angle at pre-operation and post-operation 3 days, 3 months, and 12 months.
The VAS scores and ODI scores of 3 day, 3 month, and 12 month after PVP were significantly improved compared with those before operation (
P
< .05), but the Cobb angle and vertebral kyphosis angle were not significantly improved compared with those before operation (
P
> .05).
PVP can effectively relieve the pain caused by old OVCF, and the motor ability of the patients is improved obviously. However, the recovery of Cobb angle and vertebral kyphosis angle was not obvious.
In this study, based on the high-temperature characteristics of Western China tight oil reservoirs, a phenolic-larch tannin, temperature-resistant, plugging agent was synthesized by changing the mass fractions of larch tannin, double cross-linking agent, and accelerator. Young’s modulus of the dispersed gel was directly measured by an atomic force microscope, and the macroscopic plugging performance was evaluated by a physical simulation experiment of the artificially fractured natural core from Western China tight oil oilfield, thereby establishing a mapping relationship between the two. Research indicates that the formula of the high-temperature-resistant tannin system optimized by the experiment is
3.0
%
sulfonated
tannin
+
3.0
%
formaldehyde
cross
‐
linking
agent
+
1.0
%
phenol
cross
‐
linking
agent
+
0.05
%
MnS
O
4
accelerator
; the mechanical strength of the tannin gel and its plugging performance have a linear relationship. When Young’s modulus rises from 18.74 to 63.89 KPa, the plugging rate rises from 94.11% to 97.44%.
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