# A New Prediction Model of Annular Pressure Buildup for Offshore Wells
## 8 Conclusions  
Based on elastic deformation theory, a new deformation model of the casing sealing section is established, and a new prediction method for multi-string annular pressure  
Figure 19: Relationship between elastic modulus of cement sheath and pressure.  
Figure 20: The impact of A annulus pressure release on B and C annulus pressures.  
buildup is developed. The annular pressure buildup predicted by considering the deformation of the casing sealing section is about 13% lower than that predicted by not considering this factor, which is closer to the measured value. Based on the obtained results, the following conclusions can be drawn.  
(1) The annular pressure increases with the increase in the elastic modulus of the casing while decreasing with the increase in Poisson's ratio.  
(2) Based on elastic deformation theory, the deformation model of the casing sealing section is established, and the prediction method of multi-string annular pressure buildup is improved. The predicted annular pressure buildup value considering casing sealing section deformation is about 13% lower than that without considering this factor. This also shows that the predicted annular pressure buildup value considering casing sealing section deformation is lower than that without considering casing sealing section deformation and is more consistent with reality.  
(3) Temperature rise is the most important factor causing the annular pressure buildup, and the annulus pressure buildup increases with the increase in temperature. The annular fluid temperature profile is related to oil and gas well production and production time. The annulus fluid temperature increases rapidly at the initial stage of production, then slowly increases and finally becomes stable. The annular fluid temperature profile increases slowly with the increase in oil and gas production.  
(4) Reducing the pressure in the A annulus also releases the annulus pressure buildup in the B and C annulus, while the annulus pressure buildup in the B annulus decreases faster.  
Conceptualization, R.X. and L.Z.; methodology, R.X.; software, R.X.; validation, R.X. and L.Z.; formal analysis, R.X.; investigation, R.X.; resources, L.Z.; data curation, R.X.; writing--original draft preparation, R.X.; writing--review and editing, L.Z.; visualization, R.X.; supervision, L.Z.; project administration, R.X.; funding acquisition, R.X. All authors have read and agreed to the published version of the manuscript.  
This work is supported by the Major technology projects of China National Offshore Oil Corporation Limited (KJGG-2022-17-05).  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
Author [PERSON] was employed by the company CNOOC Research Institute Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this study received funding from China National Off-shore Oil Corporation Limited. The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication.