Numerical Investigation of the Impacts of Borehole Breakouts on Breakdown Pressure

Energies

卷:12

BerntS. Aadnoy¹  Hua Zhang²  Shunde Yin² 

[1] Department of Petroleum Engineering, University of Stavanger, 4036 Stavanger, Norway;

[2] Department of Petroleum Engineering, University of Wyoming, Laramie, WY 82071, USA;

关键词: borehole breakouts;    finite element method;    breakdown pressure;    in situ stress;   

DOI  :  10.3390/en12050888

来源: DOAJ

【 摘 要 】

Borehole breakouts appear in drilling and production operations when rock subjected to in situ stress experiences shear failure. However, if a borehole breakout occurs, the boundary of the borehole is no longer circular and the stress distribution around it is different. So, the interpretation of the hydraulic fracturing test results based on the Kirsch solution may not be valid. Therefore, it is important to investigate the factors that may affect the correct interpretation of the breakdown pressure in a hydraulic fracturing test for a borehole that had breakouts. In this paper, two steps are taken to implement this investigation. First, sets of finite element modeling provide sets of data on borehole breakout measures. Second, for a given measure of borehole breakouts, according to the linear relation between the mud pressure and the stress on the borehole wall, the breakdown pressure considering the borehole breakouts is acquired by applying different mud pressure in the model. Results show the difference between the breakdown pressure of a circular borehole and that of borehole that had breakouts could be as large as 82% in some situations.

【 授权许可】

Unknown