A novel analytical transient heat-conduction time function for heat transfer in steam injection wells considering the wellbore heat capacity

Geothermal power generation from abandoned oil wells is a new way to utilize geothermal energy. An analysis model based on transient formation heat transfer is presented in this paper. Through the double-pipe heat exchanger, R143a is used as working fluid for obtaining geothermal energy from abandoned oil wells. The influence of insulation on heat transfer from the recovery well to the injection well is investigated. The result shows that the outlet temperature of fluid leaving the recovery well gradually increases with thickness of insulation increasing. The outlet temperature of fluid with the insulation of 0.03m polystyrene drops by 6K as compared to the outlet temperature with the perfect insulation.At the same thickness of insulation, the difference of the outlet temperature between with the insulation of polystyrene and with the perfect insulation decreases with the inlet velocity of fluid entering the injection well increasing.

show abstract

“…Thermal recovery methods, especially for steam injection techniques, including steam stimulation, steam flooding and steam assisted gravity drainage (SAGD), are extensively used to reduce the viscosity of heavy oil during production. However, injecting steam into wellbore would inevitably result in heat exchange between the wellbore fluid and its surrounding formation (Cheng, et al, 2011). In addition, the thermophysical properties of steam, such as pressure, temperature and quality, would change as steam flows along the wellbore.…”

Section: Introductionmentioning

confidence: 99%

A New Semi-analytical Model for Predicting Steam Pressure and Temperature in Annuli

Cheng

Huang

et al. 2014

Day 1 Tue, June 10, 2014

View full text Add to dashboard Cite

An excellent design of steam injection projects requires accurate prediction of bottomhole steam pressure, temperature and quality. However, it is not always easy to meet the requirement when we design concentric dual-tubing steam injection schemes due to the complexity of downward steam/water flow in annuli. Also, previous methods for estimating pressure gradient in annuli, such as mechanistic models and empirical correlations, are either time-consuming or inaccurate.In this study, we present a new semi-analytical model to predict steam pressure and temperature in annuli. It is based on Coulter-Bardon equation and on mass and energy balances in the wellbore. A more rigorous thermodynamic behavior of steam/water mixture is taken into account. More importantly, one-to-one correspondence between pressure gradient and temperature gradient of saturated steam is reasonably developed and applied in our further derivation and simplification. It is because of the simplification that we do not have to use mechanistic models or empirical correlations to separately calculate the pressure drop in annuli, which is significantly different from previous work, including Sagar et al. (1991), Alves et al. (1992) and Hasan et al. (1994) models. Our solution procedure is straightforward, the equations of steam pressure, temperature, quality, steady-state heat transfer in the wellbore and transient heat transfer in the formation just need to be coupled and solved iteratively for each segment.Our model is validated by comparison with measured field data from Liaohe Oilfield, Petro China. The results indicate that the direction of heat transfer between inner and outer tubing depends on wellhead conditions and temperature drop in each tubing. We also show that the equivalent hydraulic diameter is not always a suitable characteristic dimension for steam/water flow in annuli. Moreover, the paper shows that our method can also be applied to single-tubing steam injection design. The predicted results from our modified model are also compared with those from CMG simulator and previous work in our study.

show abstract

A novel analytical transient heat-conduction time function for heat transfer in steam injection wells considering the wellbore heat capacity

Cited by 127 publications

References 23 publications

Studies on geothermal power generation using abandoned oil wells

Studies on geothermal power generation using abandoned oil wells

An Analysis of Insulation of Abandoned Oil Wells Reused for Geothermal Power Generation

A New Semi-analytical Model for Predicting Steam Pressure and Temperature in Annuli

Contact Info

Product

Resources

About