Adiabatic behavior of gas wells due to natural reservoir fines migration: analytical model and CFD study

S Senthil,Venkat Pranesh,S Ravikumar,S Mahalingam

doi:10.1007/s13202-019-0670-5

Abstract

The adiabatic behavior of natural gas production well is frequently neglected in the reservoir formation damage study. The temperature of surrounding formation contributes to the smooth flow of natural gas in the wellbore. The heat transfer from the formation and geothermal gradient plays vital role in the efficient transport of gas in the subsurface formation and wellbore. But, fine particles which are attached to the rock surface migrate and are trapped in the pore throats, and as a result, there is deterioration in the permeability. The detachment of fines occurs due to high reservoir temperature and gas internal energy and temperature. Therefore, this paper conducts theoretical and numerical investigations on the adiabatic behavior of natural gas production well due to in situ reservoir fines migration. Firstly, an analytical model is developed and then, numerical models were constructed using CFD simulation tool to study the adiabatic nature of a gas well. A total of 24 cases were run in simulation, and input temperatures such as 200 °C, 250 °C, 300 °C, 350 °C, 400 °C and 450 °C were given for modeling. The results revealed that there was no sign of heat transfer from the wellbore to the surroundings. There was a heat circulation only within the wellbore. During the adiabatic state, the pressure in the central zone of the gas well is moderate, but rises linearly on the radial sides.

Highlights

BP Energy Outlook suggests that the global consumption of natural gas is anticipated to rise more rapidly than other fossil fuels, and the shale gas production rises 5.2% per year, which is attributed to 60% of the growth in natural gas production (Dale 2017)
This paper successfully demonstrated the adiabatic behavior of a natural gas well due to in situ reservoir fines migration
Based on the analytical and numerical modeling, the following conclusions can be drawn: 1. We have presented a new analytical model for fines migration and well adiabatic state prediction

Summary

Introduction

BP Energy Outlook suggests that the global consumption of natural gas is anticipated to rise more rapidly than other fossil fuels, and the shale gas production rises 5.2% per year, which is attributed to 60% of the growth in natural gas production (Dale 2017). Colloidal forces and the imbalance in mechanical equilibrium cause fines to detach from the rock grain to mobilize along with the displacing fluid, thereby plugging the pore space and restricting the permeability which leads to well impairment and production decline. This mechanism of well impairment is due to fines migration known as reservoir formation damage which harms the natural gas industry. Kaolinite is a common clay which is presented in the porous surface of reservoir rocks, and like colloids, generally, fines have a size of the order 1 μm and a net surface charge (Raha et al 2007).

Methods

Results

Conclusion