Influence of metal casing on the electric field in a cased hole

Authors:

Yinchuan Wu, Xi’an Shiyou University, Xi’an, Shaanxi, China

Baolong Guo, Xidian University, Xi’an, Shaanxi, China

Miaoyu Zhang, Xidian University, Xi’an, Shaanxi, China

Abstract:

Purpose. To study the influence of metal casing parameters (casing conductivity and casing thickness) on the electrical field and the second derivative of potential in cased hole formation resistivity technology.

Methodology. The calculation formulas of the electrical field and the second derivative of potential were derived in multi-layer media. Then the models of nondefective casing well and corrosion casing well were built in COMSOL soft. Moreover, both the electric field and the second derivative of potential were numerically calculated for nondefective casing well and corrosion casing well separately. Meanwhile, the influence of metal casing was analyzed.

Findings. The lower the conductivity of the metal casing is, the stronger the electric field and the second derivative of potential are; the electric field and the second derivative of potential are affected by metal casing parameters. These changes are always in close relation to corrosion defects in metal casing.

Originality. The models of cased hole were built in finite element analysis soft (COMSOL). The relation curve between the electrical field and casing parameters (conductivity and casing thickness) was obtained. The influence rule of metal casing was analyzed in detail.

Practical value. The results are applied to instrument design and logging interpretation.

References:

1. Wu, Y.C., Zhang, J.T. and Yan, Z.G. (2006), “An overview of the logging technology of formation resistivity through casing”, China Petroleum Instruments, vol. 20, no.5, pp. 1−5.

2. B. Wenzhuo C. Mingyu Z.Wei. (2012), “A Verification and Validation Method for Calculation Model of Space”, Acta optica sinica, vol.30, no.11, pp. 2249−2255.

3. Yang, Y., Liu, S.H., Li, F. (2013), “Research progress in casing detection technology”, China Petroleum Machinery, vol. 41, no.8, pp. 17−22.

4. Wang, C.R., Li, Z.H., Wang, C.J. (2012), “Study and application of the new casing inspection combination well logging technology in Tuha oilfield”, China Petroleum Instruments, vol.26, no.1, pp. 45−47.

5. Kaufman, A.A. (1990), “The Electrical Field in a Borehole with a Casing”, Geophysics, vol. 55, no.1, pp. 29−38.

6. Gao, J., Liu, F.P., Bao, D.Z. (2008), “Responses simulation of through-casing resistivity logging in heterogeneous-casing wells”, Chinese Journal of Geophysics, vol. 51, no.4, pp. 1255−1261.

7. Zhou, J.H., Wang, L., Yuan, R. (2013), “Analysis on Effect of Casing Collar on Formation Resistivity Logging Through Casing”, Progress in Geophysis (in Chinese), vol. 28, no.1, pp. 421−426.

8. Liu, Y., Liu, G.Q. (2014), “Numerical simulation and analysis on the influence of casing inhomogeneity on through-casing resistivity logging response”, Chinese Journal of Geophysics, vol. 57, no.4, pp. 1345−1355.

9. Gao, J., Ke, S.Z., Wen, B.J. (2010), “Introduction to numerical simulation of electrical logging and its development trend”, Well Logging Technology (in Chinese), vol. 34, no.1, pp. 1−5.

10. Wu, Y.C., Guo, B.L., Zhang, J.T. (2014), “Response characteristics of cased hole formation resistivity logging”, International Journal of Earth Science and Engineering, vol. 7, no.5, pp. 2075−2081.

 

 

2015_05_wu
2016-02-03  1.04 MB  944