Modeling of wellbore multiphase flow with free gas influx during horizontal drilling in marine hydrate reservoirs

Author(s):  
Youqiang Liao ◽  
Qian Sun ◽  
Zhiyuan Wang ◽  
Xiaohui Sun ◽  
Wenqiang Lou ◽  
...  
2009 ◽  
Vol 12 (04) ◽  
pp. 595-609 ◽  
Author(s):  
Shahab Gerami ◽  
Mehran Pooladi-Darvish

Summary Development of natural gas hydrates as an energy resource has gained significant interest during the past decade. Hydrate reservoirs may be found in different geologic settings including deep ocean sediments and arctic areas. Some reservoirs include a free-gas zone beneath the hydrate and such a situation is referred to as a hydrate-capped gas reservoir. Gas production from such a reservoir could result in pressure reduction in the hydrate cap and endothermic decomposition of hydrates. Well testing in conventional reservoirs is used for estimation of reservoir and near-wellbore properties. Drawdown testing in a hydrate-capped gas reservoir needs to account for the effect of gas from decomposing hydrates. This paper presents a 2D (r,z) mathematical model for a constant-rate drawdown test performed in a well completed in the free-gas zone of a hydrate-capped gas reservoir during the earlytime production. Using energy and material balance equations, the effect of endothermic hydrate decomposition appears as an increased compressibility in the resulting governing equation. The solution for the dimensionless wellbore pressure is derived using Laplace and finite Fourier cosine transforms. The solution to the analytical model was compared with a numerical hydrate reservoir simulator across some range of hydrate reservoir parameters. The use of this solution for determination of reservoir properties is demonstrated using a synthetic example. Furthermore, the solution may be used to quantify the contribution of hydrate decomposition on production performance. Introduction In recent years, demands for energy have stimulated the development of unconventional gas resources, which are available in enormous quantities around the world. Gas hydrate as an unconventional gas resource may be found in two geologic settings (Sloan 1991):on land in permafrost regions, andin the ocean sediments of continental margins. During the last decade, extensive efforts consisting of detection of the hydrate-bearing areas, drilling, logging, coring of the intervals, production pilot-testing, and mathematical modeling of hydrate reservoirs have been pursued to evaluate the potential of gas production from these gas-hydrate resources.


2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Xiaohui Sun ◽  
Baojiang Sun ◽  
Yonghai Gao ◽  
Zhiyuan Wang

The interaction between hydrated bubble growth and multiphase flow dynamics is important in deepwater wellbore/pipeline flow. In this study, we derived a hydrate shell growth model considering the intrinsic kinetics, mass and heat transfer, and hydrodynamics mechanisms in which a partly coverage assumption is introduced for elucidating the synergy of bubble hydrodynamics and hydrate morphology. Moreover, a hydro-thermo-hydrate model is developed considering the intercoupling effects including interphase mass and heat transfer, and the slippage of hydrate-coated bubble. Through comparison with experimental data, the performance of proposed model is validated and evaluated. The model is applied to analyze the wellbore dynamics process of kick evolution during deepwater drilling. The simulation results show that the hydrate formation region is mainly near the seafloor affected by the fluid temperature and pressure distributions along the wellbore. The volume change and the mass transfer rate of a hydrated bubble vary complicatedly, because of hydrate formation, hydrate decomposition, and bubble dissolution (both gas and hydrate). Moreover, hydrate phase transition can significantly alter the void fraction and migration velocity of free gas in two aspects: (1) when gas enters the hydrate stability field (HSF), a solid hydrate shell will form on the gas bubble surface, and thereby, the velocity and void fraction of free gas can be considerably decreased; (2) the free gas will separate from solid hydrate and expand rapidly near the sea surface (outside the HSF), which can lead to an abrupt hydrostatic pressure loss and explosive development of the gas kick.


SPE Journal ◽  
2019 ◽  
Vol 24 (05) ◽  
pp. 1947-1956 ◽  
Author(s):  
Syed Raza Rehman ◽  
Alap Ali Zahid ◽  
Anwarul Hasan ◽  
Ibrahim Hassan ◽  
Mohammad A. Rahman ◽  
...  

Summary Horizontal drilling technology has shown to improve the production and cost–effectiveness of the well by generating multiple extraction points from a single vertical well. The efficiency of hole cleaning is reduced because of the solid–cuttings accumulation in the annulus in cases of extended–reach drilling. It is difficult to study the complex flow behavior in a drilling annulus using the existing visualization techniques. In this study, experiments were carried out in the multiphase flow–loop system consisting of a simulated drilling annulus using electrical resistance tomography (ERT) and a high–speed camera. Real–time tomographic images (quantitative visualization) of multiphase flow from ERT were compared to the actual photographs of the flow conditions in a drilling annulus. The quantitative analysis demonstrates that ERT has a wide potential application in studying the hole–cleaning issues in the drilling industry.


Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1426
Author(s):  
Amina Shynybayeva ◽  
Luis R. Rojas-Solórzano

Multiphase flows are present in many natural phenomena, processing technologies, and industries. In the petroleum industry, the multiphase flow is highly relevant, and special attention is paid to the development of predictive tools that determine flow conditions to guarantee safe and economic hydrocarbon extraction and transportation. Hydrodynamic aspects such as pressure drop and holdup are of primary relevance for the field engineer in daily operations like pumping power calculation and equipment selection and control. Multiphase flow associated with oil production is usually a mixture of liquids and gas. The hydrodynamic behavior has been studied in different pipeline configurations (i.e., vertical ascending/descending and horizontal/inclined pipelines). However, the available information about flow patterns as well as the general conditions present in horizontal annuli is incomplete, even if they are of fundamental relevance in today’s horizontal drilling, production, and well intervention in many oil wells around the world. This review aims to present an in-depth revision of the existing models developed to predict two-phase flow patterns and hydrodynamic conditions in annuli flow, focusing mainly on, but not limited to, horizontal configuration. Key flow parameters and effects caused by annuli geometry and the physical properties of fluids are extensively discussed in the present paper. Different empirical correlations and mechanistic and numerical models on two-phase flow through horizontal/inclined pipelines and in both concentric and eccentric annuli are analyzed. Some of these models partially agree with experimental results and show acceptable predictions of frictional pressure loss and flow patterns. Limitations in current models and challenges to be faced in the next generation of models are also discussed.


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