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Communication Dans Un Congrès Année : 2023

Dynamic Bottom Hole Stress Reconstructing process induced by intensifier jet slotting in deep geothermal drilling

Huajian Wang
  • Fonction : Auteur
Hualin Liao
  • Fonction : Auteur
Hedi Sellami
  • Fonction : Auteur
John-Paul Latham
  • Fonction : Auteur
Jiansheng Xiang
  • Fonction : Auteur
Laurent Gerbaud

Résumé

The deep geothermal reservoir is mainly hot dry rock with high yield strength, strong abrasiveness, high in-situ stress and poor drillability, which lowing the rate of penetration in deep geothermal drilling. Increasing hard rock drilling rates of deep geothermal reservoirs, a novel drilling technology to release stress of bottom hole rock by jet slotting is proposed, which based on ORCHYD project. At present, it is generally believed that high pressure water jet plays an auxiliary role in rock breaking and rock cleaning, the effect of stress release on bottom hole which has received only scant attention. In order to analyze the stress release effect by jet slotting, the jet features, the slotting characteristics with different jet pressure and the stress release process induced by jet slotting need to be studied. Firstly, the jet features with different outlet pressures are obtained by means of computational fluid dynamics. Secondly, based on the above jet features, the characteristics of slotting with different jet features are analyzed. Finally, the release process of effective stress in the slotting process is studied. The results show that the inlet pressure does not affect the length of potential core, which is about 6 times the nozzle diameter. Within the length of potential core, the impinging pressure is equal to the nozzle drop. The depth of the groove is mainly affected by the action time and jet pressure. When the pressure is 150MPa, the groove depth can reach to 15mm, and with the increasing diameter of the nozzle, the width of the groove keeps getting bigger and bigger. The expansion of the slotting range significantly increases the release efficiency of axial effective stress and enlarges the stress release range of axial effective stress, and the effective stress fluctuation of rock is obvious in the process of slotting. The axial effective stress release efficiency is hardly affected by the range of groove in the area the drilling bit acting and shows a slight increase with the expansion of the slotting range. The stress release method and results of simulations in this paper have a guiding signification for understanding the technique still further.
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Dates et versions

hal-04437358 , version 1 (04-02-2024)

Identifiants

  • HAL Id : hal-04437358 , version 1

Citer

Huajian Wang, Hualin Liao, Hedi Sellami, John-Paul Latham, Jiansheng Xiang, et al.. Dynamic Bottom Hole Stress Reconstructing process induced by intensifier jet slotting in deep geothermal drilling. World Geothermal Congress, Sep 2023, Beijing (CH), China. ⟨hal-04437358⟩
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