Page 232 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

216 Gas Wettability of Reservoir Rock Surfaces with Porous Media

60%
Percentage of suspension that accounts for total mass 40% 6–8 meshes
50%

30%
8–10 meshes
10–20 meshes
20%
10%
0% 20–40 meshes
0.0% 0.1% 0.2% 0.3% 0.4% 0.5%
FGC-1 Concentration
FIGURE 6.14
FGC-1 cuttings carrying rate for different mesh numbers.

different hole drift angles. This device is composed of a liquid outlet, vertical
well section, variable angle bending connection, inclined well section, liquid
inlet, gas inlet, and drill stem. The simulated HD/VD was 2B3, the simulated
inclined angles were 0, 30, 45, 60, 90 degrees, etc.
During the experimental process, the FGC-1 cutting carrying agent at different
concentrations were added into the saltwater drilling fluid system to measure
its carrying effects in the drilling fluid. The experimental results are shown in
Fig. 6.4. It can be seen from the figure that when FGC-1is not added, the cut-
ting carrying effect of the drilling fluidis not satisfactory. At a certain grain
diameter of rock cuttings, with increasing concentration of FGC-1 cutting car-
rying agent, the quantity of cuttings carried to the liquid surface by bubbles
increases. When the concentration of FGC-1 cutting carrying agent is 0.4% and
the grain diameter of rock cuttings is between 0.90B2.00 mm, the carried cut-
tings account for 77.2% of the total mass. When the concentration of FGC-1 is
greater than 0.5%, the extent to which cuttings are carried slows. Therefore,
during the drilling process, the optimum concentration of FGC-1 cutting carry-
ing agent should be maintained around 0.4% (Fig. 6.14).

6.3 TRAPEZOID PROTECTION WATER-INJECTION
TECHNOLOGY FOR LOW-PERMEABILITY AND EXTRA-
LOW-PERMEABILITY RESERVOIRS
6.3.1 Research Status of Water Injection
Injecting water into reservoirs to supplement the stratum energy and to
increase the yield of the corresponding production wells is an important fea-
ture of oilfield development. Low- and extra-low-permeability reservoirs may
be damaged due to features such as small pore-throat of reservoirs, capillary
phenomena, Jamin phenomena, hydration swelling, and severe water-blocks.
It is hard to inject small quantities of water at high injection pressure into the
reservoirs. Further, under the same conditions, the quantity injected gradually