分段压裂过程中射孔段水泥环密封 完整性的数值模拟.

The stress concentration could easily aggravate the damage of perforated cement sheath due to the perforation hole in horizontal wells during staged fracturing. In addition, the wall of perforation hole was directly pressed by the high-pressure fracturing fluid, making cement integrity more challenged. A fully coupled thermo-hydro-mechanical model was set up to simulate the temperature and the stress variation of the cement sheath during fracturing, and the influence of casing pressure, fracturing fluid displacement, cement elastic modulus, hole diameter and density on the cement integrity was analyzed. The results show that there is shear failure on casing / cement interface, cement / rock interface and the hole wall during fracturing process. Considering the coupling of transient temperature and pressure, the risk of failure at the cement hole is increased. The fracturing fluid displacement, hole diameter and density have little effect on the tangential stress of the cement sheath, although a lower casing pressure and cement elastic modulus can reduce the shear failure coefficient to some extent, it is difficult to avoid the shear failure at the initial stage of hydraulic fracturing. [ABSTRACT FROM AUTHOR]