Influence of Heterogeneous Reservoirs with Different Depths on Casing Deformation in Fuling Area

Abstract:

In shale gas horizontal well fracturing operations, casing deformation and cement ring damage occur mostly in heterogeneous formations. Based on the characteristics of shale gas reservoirs in China and related literatures, this paper establishes a finite element model of heterogeneous stratum for the Fuling shale gas field and studies the effects of heterogeneity on casing deformation at different depths. In the heterogeneous stratigraphic model, the effects of shallow reservoir heterogeneity and deep reservoir heterogeneity on casing deformation were analyzed. The results show that the shallow reservoir heterogeneity and deep reservoir heterogeneity affect the casing deformation in different aspects; the stress that is subjected to casing in the shallow reservoir is greater than casing in the deep reservoir; at the lithological interface, the abrupt of stress change in the deep reservoir is significantly larger than that in the shallow reservoir. This conclusion is also applicable to other shale gas fields in China; In the development of shale gas resources, the shallow reservoirs should focus on the overall strength design of casings, the deep reservoirs should focus on the strength design of casings at lithological interface points.

• Periodical: Materials Science Forum (Volume 944)
• Pages: 881-886
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.944.881
• Online since: January 2019
• Authors: Nan Ma*, Jun Li
• Keywords: Casing Failure, Finite Element Method, Formation Heterogeneity, Wellbore Safety

References

[1] Liu Yang, Yan Haibing, Yu xin etc. Negative impacts of borehole pressure change on cement sheath sealing integrity and countermeasures[J]. Natural Gas Industy. 2014, 34(04): 95-98.

[2] Dong Dazhong, Zou Caineng, Dai Jinxing etc. Suggestions on the development strategy of shale gas in China[J]. Natural Gas Geoscience. 2016, 27(3): 397-406.

[3] Zou Caineng, Dong Dazhong, Wang Yuman etc. Shale gas in China: characteristics, challenges and prospects(II)[J]. Petroleum Exploration And Development. 2016, 43(2): 166-178.

[4] Kuila U, Dewhurst D N, Siggins A F ect. Stress anisotropy and velocity anisotropy in low porosity shale[J]. Tectonophysics, 2011, 503(01): 34-44.

DOI: 10.1016/j.tecto.2010.09.023

[5] Zhang Yongze, Liu Junxin, Mao Haijun etc. Anisotropic experimental study on mechanical properties of shale under uniaxial compression[J]. Metal Mine. 2015, 7(12): 33-37.

[6] Shen Xinpu. Numerical estimation on casing integrity in hydrolic fracturing of shale gas formation[C]. China Academic Journal Electronic Publishing House. (2012).

[7] Zou Caineng, Zhao Qun, Dong Dazhong etc. Geologica characteristics, main challenges and future prospect of shale gas[J]. Natural Gas Geoscience. 2017, 28(12): 1781-1796.

DOI: 10.1016/j.jnggs.2017.11.002

[8] Guo Xusheng. Rules of Two-Factor enrichiment for marine shale gas in southern China[J]. Acta Geologica Sinica. 2014, 88(7): 1209-1218.

[9] Zou Caineng, Dong Dazhong, Wang Yuman etc. Shale gas in China: characteristics, challenges and prospects(I)[J]. Petroleum Exploration And Development. 2015, 42(6): 689-701.

[10] Wu Xingchun, Wang Sijing, Ding Enbao etc. Relationship between rock mass deformability modulus and the depth[J]. Chinese Journal of Rock Mechanics and Engineering. 1998, 17(5): 487-492.

[11] Zhang Xiaotong. Deformation characteristics of saturated-unsaturated soil under elastic modulus varying with depth[D]. Shanghai Jiao Tong University. (2011).