A novel approach to investigating the mechanism of permeability-induced borehole breathing in deepwater shallow formations

• Published in: Journal of petroleum science & engineering 2022-01, Vol.208, p.109331, Article 109331
• Main Authors: Gao, Reyu, Li, Jun, Yang, Hongwei, Lian, Wei, Wang, Wei
• Format: Article
• Language: English
• Subjects: Borehole breathing; Deep-water shallow formation; Mud loss; The mechanism of permeability-induced
• ISSN: 0920-4105; 1873-4715
• DOI: 10.1016/j.petrol.2021.109331

Due to the uniqueness of deep-water shallow formations, there is no fracture system around the wellbore when borehole breathing is observed in this part of the formation. Therefore, the inducing mechanism of the opening/closing of the fracture network cannot reasonably explain this type of borehole breathing. In this study, a new mechanism of permeability-induced is proposed to explain borehole breathing, based on the fact that there is no fracture system around the well and the formation has the characteristics of high permeability and porosity. By using the stress and seepage coupling method in the porous elastic medium, a new model is established to simulate and describe permeability-induced borehole breathing. Through comparison with actual cases, this model can effectively simulate the typical characteristics of fluid loss-flow back in borehole breathing. This study also analyzed the influence of factors such as formation parameters and mud rheological parameters on the borehole breathing caused by permeability. According to the results of the study, the use of a smaller diameter wellbore and agents that can adjust related parameters (such as loss-reducing circulating material) can effectively inhibit wellbore breathing while drilling. •A new mechanism of permeability-induced is proposed to explain borehole breathing.•A novel model is established to simulate and describe the borehole breathing caused by mechanism of permeability-induced.•The typical characteristics of fluid loss and return in wellbore breathing are simulated.•Analysis of the effects of different factors on borehole breathing.