The damage mechanisms of fracturing fluid on production in tight gas reservoirs

AbstractHydraulic fracturing is an important technical means to improve the development effect of low-permeability oil and gas reservoirs. However, for low pressure, low-permeability, tight, and high-clay sandstone gas reservoirs, conventional propped fracturing can cause serious damage to the reservoir and restrict the fracturing effect. The pre-acid fracturing technology combines acid treatment technology with sand-fracturing technology. A pre-acid system that meets special performance requirements is injected before fracturing. The pre-acid reduces the formation fracture pressure and removes clay damage. During acid flowback, the fracturing fluid is promoted to break the gel, dissolve the fracturing fluid residue and polymer filter cake, clean the supporting cracks, and effectively improve the fracturing effect. This study analyzes the process principle and technical advantages of the pre-acid fracturing technology based on the laboratory evaluation of the fracturing damage mechanism of low-permeability tight gas reservoirs. To meet the performance requirements of low-permeability tight gas reservoirs and pre-acid fracturing technology, a set of polyhydrogen acid system with long-lasting slow reactivity, low damage, and low corrosion was developed and used as the pre-fracturing acid. The acid system is mainly composed of the main agent SA601 and the auxiliary agent SA701. Then, on the basis of laboratory experiments, this acid system is used as the fracturing pre-acid to evaluate the fracturing improvement effect. The results show that the fracturing fluid system can better dissolve the fracturing fluid filter cake and remove the fracturing fluid damage.

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Overcoming Hydraulic Fracturing Challenges in High Temperature and Tight Gas Reservoirs of Saudi Arabia with an Enhanced Fracturing Fluid System

10.2523/iptc-17686-ms ◽

2014 ◽

Cited By ~ 1

Author(s):

S. M. Al-Driweesh ◽

Alaa A. Dashash ◽

Ataur R. Malik ◽

Jairo Leal ◽

Eduardo Soriano ◽

...

Keyword(s):

Saudi Arabia ◽

High Temperature ◽

Hydraulic Fracturing ◽

Tight Gas ◽

Fracturing Fluid ◽

Gas Reservoirs ◽

Fluid System ◽

Tight Gas Reservoirs

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Investigation of a critical choke during hydraulic-fracture flowback for a tight sandstone gas reservoir

Journal of Geophysics and Engineering ◽

10.1093/jge/gxz088 ◽

2019 ◽

Vol 16 (6) ◽

pp. 1178-1190

Author(s):

Jiachen Huang ◽

Jinghong Hu ◽

Wenting Zeng ◽

Yuan Zhang

Keyword(s):

Material Balance ◽

Optimization Method ◽

Tight Gas ◽

Fracturing Fluid ◽

Gas Reservoirs ◽

Tight Sandstone ◽

Gas Reservoir ◽

Tight Gas Reservoirs ◽

Wellhead Pressure ◽

Secondary Damage

Abstract Low porosity and permeability in a tight sandstone gas reservoir can cause problems during fracturing. If the fracturing fluid cannot be discharged in a timely fashion after fracturing, the fracturing fluid will move into the deep formation and result in secondary damage. Conversely, if the flowback rate of the fracturing fluid is too high, it will cause the proppant to backflow and reduce the efficiency of fracturing operation. Therefore, it is very important to control the choke sizes and flowback rates for the flowback process of a tight sandstone reservoir. In this study, a model of the time of the closed fracture considering the principle of material balance is built. Subsequently, the relationship between the wellhead pressure and the optimum diameter of the choke at different times is obtained using hydrodynamics and particle dynamics theory. Finally, the proposed optimization method is applied to an actual well from the Xinjiang tight gas reservoirs. Results show that a choke diameter can be reasonably optimized under different wellhead pressures, and that fracturing fluid flows back as much as possible and without proppant backflow. A sound design of a fracturing fluid flowback system is also provided. This study presents the mechanism of post-fracturing management and provides a better understanding of the flowback system in tight gas reservoirs.

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Evaluation of Damage Mechanisms and Skin Factor in Tight Gas Reservoirs

10.2118/142284-ms ◽

2011 ◽

Cited By ~ 6

Author(s):

Hassan Bahrami ◽

Mohammad Reza Rezaee ◽

Jakov Ostojic ◽

Delair Honer Nazhat ◽

Michael Benedict Clennell

Keyword(s):

Tight Gas ◽

Gas Reservoirs ◽

Damage Mechanisms ◽

Tight Gas Reservoirs ◽

Skin Factor

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Evaluation of damage mechanisms and skin factor in tight gas reservoirs

The APPEA Journal ◽

10.1071/aj10045 ◽

2011 ◽

Vol 51 (1) ◽

pp. 639 ◽

Cited By ~ 4

Author(s):

Hassan Bahrami ◽

Reza Rezaee ◽

Delair Nazhat ◽

Jakov Ostojic

Keyword(s):

Significant Influence ◽

Permeability Reduction ◽

Tight Gas ◽

Natural Fractures ◽

Gas Reservoirs ◽

Damage Mechanisms ◽

Well Productivity ◽

Tight Gas Reservoirs ◽

Skin Factor ◽

Water Blocking

Tight gas reservoirs normally have production problems due to very low matrix permeability and significant damage during well drilling, completion, stimulation and production. Therefore, they may not flow gas at optimum rates without advanced production improvement techniques. The main damage mechanisms and the factors that have significant influence on total skin factor in tight gas reservoirs include: mechanical damage to formation rock; plugging of natural fractures by mud solid particle invasion; relative permeability reduction around wellbore as a result of filtrate invasion; liquid leak-off into the formation during fracturing operations; water blocking; skin due to wellbore breakouts; and the damage associated with perforation. Drilling and fracturing fluids invasion mostly occurs through natural fractures and may also lead to serious permeability reduction in the rock matrix that surrounds the natural or hydraulic fractures. This study represents an evaluation of different damage mechanisms in tight gas formations, and examines the factors that can have significant influence on total skin factor and well productivity. Reservoir simulation was carried out based on a typical West Australian tight gas reservoir to understand how well productivity is affected by each of the damage mechanisms, such as natural fracture plugging, mud filtrate invasion, water blocking and perforation. Furthermore, some damage prevention and productivity improvement techniques are proposed, which can help improve well productivity in tight gas reservoirs.

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