Dynamic Fractures in Tight Low-Permeability Oil Sandstone Reservoirs

2017 ◽  
Author(s):  
Jiahong Li ◽  
Xinmin Song ◽  
Tao Yu ◽  
Jianfeng Hou ◽  
Zhengdong Lei
Keyword(s):  
Low Permeability ◽  
Sandstone Reservoirs ◽  
Dynamic Fractures

scholarly journals Experimental Investigation on the Effects of CO2 Displacement Methods on Petrophysical Property Changes of Ultra-Low Permeability Sandstone Reservoirs Near Injection Wells

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 327 ◽  
Author(s):  
Qian Wang ◽  
Shenglai Yang ◽  
Haishui Han ◽  
Lu Wang ◽  
Kun Qian ◽  
...  
Keyword(s):  
Physical Properties ◽  
Pore Size ◽  
Mineral Dissolution ◽  
Co2 Injection ◽  
Low Permeability ◽  
Co2 Flooding ◽  
Formation Water ◽  
Injection Wells ◽  
Rock Interaction ◽  
Sandstone Reservoirs

The petrophysical properties of ultra-low permeability sandstone reservoirs near the injection wells change significantly after CO2 injection for enhanced oil recovery (EOR) and CO2 storage, and different CO2 displacement methods have different effects on these changes. In order to provide the basis for selecting a reasonable displacement method to reduce the damage to these high water cut reservoirs near the injection wells during CO2 injection, CO2-formation water alternate (CO2-WAG) flooding and CO2 flooding experiments were carried out on the fully saturated formation water cores of reservoirs with similar physical properties at in-situ reservoir conditions (78 °, 18 MPa), the similarities and differences of the changes in physical properties of the cores before and after flooding were compared and analyzed. The measurement results of the permeability, porosity, nuclear magnetic resonance (NMR) transversal relaxation time (T2) spectrum and scanning electron microscopy (SEM) of the cores show that the decrease of core permeability after CO2 flooding is smaller than that after CO2-WAG flooding, with almost unchanged porosity in both cores. The proportion of large pores decreases while the proportion of medium pores increases, the proportion of small pores remains almost unchanged, the distribution of pore size of the cores concentrates in the middle. The changes in range and amplitude of the pore size distribution in the core after CO2 flooding are less than those after CO2-WAG flooding. After flooding experiments, clay mineral, clastic fines and salt crystals adhere to some large pores or accumulate at throats, blocking the pores. The changes in core physical properties are the results of mineral dissolution and fines migration, and the differences in these changes under the two displacement methods are caused by the differences in three aspects: the degree of CO2-brine-rock interaction, the radius range of pores where fine migration occurs, the power of fine migration.

Wettability Alteration in Low-Permeability Sandstone Reservoirs by “SiO2–Rhamnolipid” Nanofluid

2019 ◽  
Vol 33 (12) ◽  
pp. 12170-12181 ◽  
Author(s):  
Di Wang ◽  
Shanshan Sun ◽  
Kai Cui ◽  
Hailan Li ◽  
Yejing Gong ◽  
...  
Keyword(s):  
Wettability Alteration ◽  
Low Permeability ◽  
Sandstone Reservoirs

Oil Recovery in Low Permeability Sandstone Reservoirs Using Surfactant-Polymer Flooding

2015 ◽  
Author(s):  
C. Marliere ◽  
N. Wartenberg ◽  
M. Fleury ◽  
R. Tabary ◽  
C. Dalmazzone ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Polymer Flooding ◽  
Low Permeability ◽  
Sandstone Reservoirs

Mechanism of Overpressure Formation in Deeply Burial Sandstone

2013 ◽  
Vol 295-298 ◽  
pp. 2736-2739
Author(s):  
Hai Yan Hu
Keyword(s):  
Hydrostatic Pressure ◽  
Capillary Pressure ◽  
Driving Force ◽  
Low Permeability ◽  
Gas Generation ◽  
Tight Sandstone ◽  
Gas Accumulation ◽  
Fine Grained ◽  
Sandstone Reservoirs ◽  
Induced Fractures

Overpressure is often encountered in the Jurassic tight and the overpressure is closely associated with gas generation. The pressure transfer from the over-pressurized mudstones to adjacent tight sandstones might occur through overpressure induced-fractures. The fine-grained coal containing Jurassic sandstone is sensitive to compaction, and the porosity decreases dramatically with the increase of overlying load. As gas migrates into the tight sandstones, it must overcome the capillary pressure which is greater than the hydrostatic pressure. The gas charging pressure in the tight sandstone must be higher than the capillary pressure, resulting in an overpressure buildup within the tight sandstones. Gas shows, low permeability and strong diagenesis in the overpressure of the tight sandstone system have been observed. Additionally, capillary seals are identified as playing an important role in the mechanism of the overpressure formation in tight sandstone reservoirs. Overpressure might be a driving force to create induced fractures in the interval, which has applications for crossing-formation migration and gas accumulation.

Sign in / Sign up

Export Citation Format

Share Document