Using relative permeability curves to evaluate phase trapping damage caused by water- and oil-based drilling fluids in tight-gas reservoirs

2012 ◽  
Vol 52 (1) ◽  
pp. 595 ◽  
Author(s):  
Geeno Murickan ◽  
Hassan Bahrami ◽  
Reza Rezaee ◽  
Ali Saeedi ◽  
Tsar Mitchel
Keyword(s):  
Capillary Pressure ◽  
Relative Permeability ◽  
Drilling Fluid ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Water Based ◽  
Tight Formations ◽  
Relative Permeability Curves ◽  
Tight Formation

Low matrix permeability and significant damage mechanisms are the main signatures of tight-gas reservoirs. During the drilling and fracturing of tight formations, the wellbore liquid invades the tight formation, increases liquid saturation around the wellbore, and eventually reduces permeability at the near wellbore zone. The liquid invasion damage is mainly controlled by capillary pressure and relative permeability curves. Due to high critical water saturation, relative permeability effects and strong capillary pressure, tight formations are sensitive to water invasion damage, making water blocking and phase trapping damage two of the main concerns with using a water-based drilling fluid in tight-gas reservoirs.Therefore, the use of an oil-based mud may be preferred in the drilling or fracturing of a tight formation. Invasion of an oil filtrate into tight formations, however, may result in the introduction of an immiscible liquid-hydrocarbon drilling or completion fluid around the wellbore, causing the entrapment of an additional third phase in the porous media that would exacerbate formation damage effects. This study focuses on phase trapping damage caused by liquid invasion using a water-based drilling fluid in comparison with the use of an oil-based drilling fluid in water-sensitive, tight-gas sand reservoirs. Reservoir simulation approach is used to study the effect of relative permeability curves on phase trap damage, and the results of laboratory experiments of core flooding tests in a West Australian tight-gas reservoir are shown, where the effect of water injection and oil injection on the damage of core permeability are studied. The results highlight the benefits of using oil-based fluids in drilling and fracturing of tight-gas reservoirs in terms of reducing skin factor and improving well productivity.

Lowering the phase-trap damage in tight-gas reservoirs by using interfacial tension (IFT) reducers

2013 ◽  
Vol 53 (1) ◽  
pp. 363
Author(s):  
Yangfan Lu ◽  
Hassan Bahrami ◽  
Mofazzal Hossain ◽  
Ahmad Jamili ◽  
Arshad Ahmed ◽  
...  
Keyword(s):  
Relative Permeability ◽  
Reservoir Simulation ◽  
Water Saturation ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Water Based ◽  
Tight Formations ◽  
Tight Reservoirs ◽  
Relative Permeability Curves

Tight-gas reservoirs have low permeability and significant damage. When drilling the tight formations, wellbore liquid invades the formation and increases water saturation of the near wellbore area and significantly deceases permeability of this area. Because of the invasion, the permeability of the invasion zone near the wellbore in tight-gas formations significantly decreases. This damage is mainly controlled by wettability and capillary pressure (Pc). One of the methods to improve productivity of tight-gas reservoirs is to reduce IFT between formation gas and invaded water to remove phase trapping. The invasion of wellbore liquid into tight formations can damage permeability controlled by Pc and relative permeability curves. In the case of drilling by using a water-based mud, tight formations are sensitive to the invasion damage due to the high-critical water saturation and capillary pressures. Reducing the Pc is an effective way to increase the well productivity. Using the IFT reducers, Pc effect is reduced and trapped phase can be recovered; therefore, productivity of the TGS reservoirs can be increased significantly. This study focuses on reducing phase-trapping damage in tight reservoirs by using reservoir simulation to examine the methods, such use of IFT reducers in water-based-drilled tight formations that can reduce Pc effect. The Pc and relative permeability curves are corrected based on the reduced IFT; they are then input to the reservoir simulation model to quantitatively understand how IFT reducers can help improve productivity of tight reservoirs.

Effect of liquid invasion damage and supercharging on wireline formation tester measurements in tight gas reservoirs

2012 ◽  
Vol 52 (1) ◽  
pp. 627 ◽  
Author(s):  
Joshua Andrews ◽  
Hassan Bahrami ◽  
Reza Rezaee ◽  
Hamid Reza ◽  
Sultan Mehmood ◽  
...  
Keyword(s):  
Capillary Pressure ◽  
Drilling Fluid ◽  
Gas Production ◽  
Tight Gas ◽  
Formation Pressure ◽  
Gas Reservoirs ◽  
Reliable Determination ◽  
Tight Gas Reservoirs ◽  
Tight Gas Reservoir ◽  
Measured Pressure

Wireline formation testing and measurement of true formation pressure can provide essential knowledge about the reservoir dynamic characteristics. In tight formations, a reliable determination of pressure and mobility gradients is challenging because of the tight nature of formation rock. Due to the very low reservoir permeability, the mud cake across wellbore is often ineffective in preventing filtrate invasion, thus causing the measured pressure to be higher than actual formation pressure as a result of supercharging effect. Wireline formation testing measurements are also influenced by the effects of filtrate invasion and capillary pressure, as the measured pressure is pressure of drilling fluid filtrate, the continuous phase present in the invaded region around wellbore. As a result, the measured pressure might be different to true formation pressure. This effect is more noticeable in tight gas reservoirs due to capillary pressure effect. This paper looks into estimation of true formation pressure and evaluates the effect of filtrate invasion damage and supercharging on wireline formation tester measurements in tight gas reservoirs. Numerical simulation approach is used to build the reservoir model based on data acquired from a tight gas reservoir. The model undergoes water injection followed by gas production from different testing points along the wellbore, and the corresponding pressure gradients are plotted to check for pressure matching with that of the formation fluid in the virgin region. The results indicate the significant effects of supercharging, reservoir characteristics, capillary pressure and liquid invasion damage on wireline formation pressure measurements in tight gas reservoirs.

scholarly journals Gas-water relative permeability measurement of high temperature and high pressure tight gas reservoirs

2015 ◽  
Vol 42 (1) ◽  
pp. 92-96 ◽  
Author(s):  
Jianlong FANG ◽  
Ping GUO ◽  
Xiangjiao XIAO ◽  
Jianfen DU ◽  
Chao DONG ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Relative Permeability ◽  
Tight Gas ◽  
Permeability Measurement ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs

Effect of Liquid Invasion and Capillary Pressure on Wireline Formation Tester Measurements in Tight Gas Reservoirs

2012 ◽  
Author(s):  
Joshua Thomas Andrews ◽  
Hassan Bahrami ◽  
Reza Rezaee ◽  
Sultan Mehmood ◽  
Hossein Majid Salemi
Keyword(s):  
Capillary Pressure ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs

ANALYSIS OF PRESSURE-DEPENDENT RELATIVE PERMEABILITY IN PERMEABILITY JAIL OF TIGHT GAS RESERVOIRS AND ITS INFLUENCE ON TIGHT GAS PRODUCTION

2019 ◽  
Vol 22 (13) ◽  
pp. 1667-1683
Author(s):  
Fei Mo ◽  
Zhimin Du ◽  
Xiaolong Peng ◽  
Baosheng Liang ◽  
Yong Tang ◽  
...  
Keyword(s):  
Relative Permeability ◽  
Gas Production ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs

scholarly journals Mitigation of Condensate Banking Using Thermochemical Treatment: Experimental and Analytical Study

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 800 ◽  
Author(s):  
Amjed Hassan ◽  
Mohamed Mahmoud ◽  
Abdulaziz Al-Majed ◽  
Ayman Al-Nakhli ◽  
Mohammed Bataweel ◽  
...  
Keyword(s):  
Relative Permeability ◽  
Capillary Forces ◽  
Co2 Injection ◽  
Tight Gas ◽  
Reaction Products ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
The Creation ◽  
Chemical Activator

Condensate banking is a common problem in tight gas reservoirs because it diminishes the gas relative permeability and reduces the gas production rate significantly. CO2 injection is a common and very effective solution to mitigate the condensate damage around the borehole in tight gas reservoirs. The problem with CO2 injection is that it is a temporary solution and has to be repeated frequently in the field in addition to the supply limitations of CO2 in some areas. In addition, the infrastructure required at the surface to handle CO2 injection makes it expensive to apply CO2 injection for condensate removal. In this paper, a new permanent technique is introduced to remove the condensate by using a thermochemical technique. Two chemicals will be used to generate in situ CO2, nitrogen, steam, heat, and pressure. The reaction of the two chemicals downhole can be triggered either by the reservoir temperature or a chemical activator. Two chemicals will start reacting and produce all the mentioned reaction products after 24 h of mixing and injection. In addition, the reaction can be triggered by a chemical activator and this will shorten the time of reaction. Coreflooding experiments were carried out using actual condensate samples from one of the gas fields. Tight sandstone cores of 0.9 mD permeability were used. The results of this study showed that the thermochemical reaction products removed the condensate and reduced its viscosity due to the high temperature and the generated gases. The novelty in this paper is the creation of micro-fractures in the tight rock sample due to the in-situ generation of heat and pressure. These micro-fractures reduced the capillary forces that hold the condensate and enhanced the rock relative permeability. The creation of micro-fractures and in turn the reduction of the capillary forces can be considered as permanent condensate removal.

Experimental Study on Reducing Water Phase Trapping in Tight Gas Reservoirs

2013 ◽  
Vol 295-298 ◽  
pp. 3293-3297
Author(s):  
Hao Zhang ◽  
Xiao Ning Feng ◽  
Ji Ping She ◽  
Fu You Huang ◽  
Guan Fang Li
Keyword(s):  
Water Saturation ◽  
Water Phase ◽  
Tight Gas ◽  
Prevention Measures ◽  
Gas Reservoirs ◽  
Reservoir Water ◽  
Tight Gas Reservoirs ◽  
Western Sichuan ◽  
Water Based ◽  
Western Sichuan Basin

This document explains and demonstrates how to reduce water phase trapping in tight gas reservoirs during drilling. The water phase trapping laboratory device and experiment method has been studied, through the experiments on reservoir water phase trapping of western Sichuan Basin in China, Knowing that the damage is very serious, water self absorption experiments with different periods show that porosity and permeability of cores are basically above 50%. for the reason, the high capillary pressure and low water saturation are the main factors. Water phase trapping damage prevention measures has been put forward, including avoiding using water-based operating fluid as much as possible, minimizing or even avoiding the invasion of water-based operating fluid, and reducing interfacial tension and promote smooth operating fluid flow back.

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