Page 226 - Gas Wettability of Reservoir Rock Surfaces with Porous Media

210 Gas Wettability of Reservoir Rock Surfaces with Porous Media

Table 6.8 Protection Effect Comparison of Low-permeability and Extra-
low-permeability Reservoirs in Shengli Oilfield

Well Number Protection Daily Daily Oil Yield
Measure Production Production Ratio
(t/d) Under of This
Differential Method
Pressure Unit
(t/m.d.MPa)
Chun 64-4 This method 3.2 0.064 1.408
Chun 64-3 Earlier methods 0.9 0.045
Fan 143-inclined This method 5.2 0.168 1.48
10
Fan 143-13 Earlier methods 4.7 0.113
Liang 38-flat 4 This method 24.8 0.016 1.186
Liang 38-flat 2 Earlier methods 7.3 0.013
Liang 23-inclined This method 5.9 0.12 21.83
36
Liang 23-12 Earlier methods 0.5 0.005
Liang 38-flat 7 This method 10.4 0.012 1.104
Liang 38-flat 3 Earlier methods 2.2 0.011
Fan 147-9 This method 5 0.303 1.697
Fan 147-1 Earlier methods 2 0.179

6.1.6 Reservoir Protection When Compared to Conventional
Reservoir Protection With Drilling Fluid Technology
The comparison results from field tests are as shown in Tables 6.9 and 6.10,
the protection offered by the new drilling fluid technology to reservoirs is
better and “zero” damage was observed, thereby improving the surface proper-
ties better than the currently used domestic technologies.

6.2 DRILLING FLUID CUTTINGS CARRYING
TECHNOLOGY
6.2.1 Development Status in Large Displacement Wells
Using Cuttings Carrying Technology
The productivity of wells with complicated structures including horizontal
wells and large displacement wells is more than 3 times that of plumb wells.
They are the main well types for efficient exploration and development of
hydrocarbon resources in recent years. However, due to gravity, cuttings are
easier to pile up in the horizontal and angular sections and form cutting beds
affecting the cleanliness of wells. If the well is not clean enough, the risk of
complicated conditions, such as sticking, lost circulation, drilling fluid density
out of control, the cementing operation failure, and even abandoning the