Productivity Increase Through Hydraulic Fracturing in Conventional and Tight Gas Reservoirs - Expectation versus Reality

2012 ◽  
Author(s):  
Zillur Rahim ◽  
Hamoud Ali Al-anazi ◽  
Adnan Kanaan ◽  
Ali Hussain Habbtar ◽  
Ahmed M. Omair ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Productivity Increase

Long-period, long-duration seismic events during hydraulic stimulation of shale and tight-gas reservoirs — Part 1: Waveform characteristics

Geophysics ◽  
2013 ◽  
Vol 78 (6) ◽  
pp. KS97-KS108 ◽  
Author(s):  
Indrajit Das ◽  
Mark D. Zoback
Keyword(s):  
Hydraulic Fracturing ◽  
Seismic Events ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Hydraulic Stimulation ◽  
Tight Gas Reservoirs ◽  
Long Period ◽  
Long Duration ◽  
Low Amplitude ◽  
Stimulation Of

Long-period long-duration (LPLD) seismic events are relatively low-amplitude signals that have been observed during hydraulic fracturing in several shale-gas and tight-gas reservoirs. These events are similar in appearance to tectonic tremor sequences observed in subduction zones and transform fault boundaries. LPLD events are predominantly composed of S-waves, but weaker P-waves have also been identified. In some cases, microearthquakes are observed during the events. Based on the similarity with tectonic tremors and our observations of several impulsive S-wave arrivals within the LPLD events, we interpret the LPLD events as resulting from the superposition of slow shear-slip events on relatively large faults. Most large LPLD waveforms appear to start as a relatively slower, low-amplitude precursor, lacking clear impulsive arrivals. We estimate the energy carried by the larger LPLD events to be [Formula: see text] times greater than a [Formula: see text] microseismic event that is typical of the events that occur during hydraulic stimulation. Over the course of the entire stimulation activity of five wells in the Barnett formation (each hydraulically fractured ten times), the LPLD events were found to cumulatively release over an order of magnitude higher energy than microearthquakes. The large size of these LPLD events, compared to microearthquakes, suggests that they represent slip on relatively large faults during stimulation of these extremely low-permeability reservoirs. Moreover, they imply that the accompanying slow slip on faults, probably mostly undetected, is a significant deformation process during multistage hydraulic fracturing.

Solutions for Better Production in Tight Gas Reservoirs Through Hydraulic Fracturing

2009 ◽  
Author(s):  
James Ohioma I. Arukhe ◽  
Roberto Aguilera ◽  
Thomas Grant Harding
Keyword(s):  
Hydraulic Fracturing ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs

scholarly journals Pre-acid system for improving the hydraulic fracturing effect in low-permeability tight gas reservoir

2021 ◽  
Vol 11 (4) ◽  
pp. 1761-1780
Author(s):  
Nianyin Li ◽  
Fei Chen ◽  
Jiajie Yu ◽  
Peihong Han ◽  
Jia Kang
Keyword(s):  
Hydraulic Fracturing ◽  
Filter Cake ◽  
Low Permeability ◽  
Tight Gas ◽  
Acid System ◽  
Fracturing Fluid ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Acid Fracturing ◽  
Performance Requirements

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.

Water Management and Hydraulic Fracturing Operations in Middle Eastern Tight Gas Reservoirs

2021 ◽  
Author(s):  
Abhijith Suboyin ◽  
Md Motiur Rahman ◽  
Mohamed Haroun
Keyword(s):  
Water Management ◽  
Middle East ◽  
Hydraulic Fracturing ◽  
Arid Regions ◽  
Middle Eastern ◽  
Management Strategies ◽  
Design Parameters ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs

Abstract Tight gas reservoirs in the Middle East are renowned for their extremely low porosity and low permeability along with their high heterogeneity. Over the past few decades, hydraulic fracturing has gained significant attention, particularly to stimulate such formations which were previously considered uneconomical and inefficient. Even though over a million hydraulic fracturing operations were conducted across the globe, they are still associated with a considerable amount of risk. Studies have shown that an effective, efficient and economical approach coupled with tailored water management strategies are critical for their successful development, especially in arid regions such as the Middle East. In this research, a realistic field model was constructed and advanced to analyze hydraulic fracture propagation in the presence of natural fractures for a candidate Middle Eastern tight gas reservoir. This flexible simulation model allowed to investigate, identify and characterize the key fracture design parameters that influenced fracture geometry for the candidate field. This further allowed to categorize and propose a unique tailored workflow to highlight the governing parameters for efficient water management strategies for arid regions such as the Middle East. In addition, the results have been extended to current field practices and cases. The constructed model can greatly assist in streamlining hydraulic fracturing operations and water management strategies in regions such as the Middle East, where resources such as water and proppants can be considered as constraints. In addition, the investigation further highlights the strong need and potential opportunities for the key players in the region to leverage their technology for an efficient water management value chain. The variables and the workflow presented in this study further demonstrates how there is no bespoke solution to a ‘best approach’ in such regions. However, a workflow identifying the key dominant categories, such as a tailored one proposed in this study, may assist in the creation of more efficient and practical strategies while contributing to the overall process chain.

Some Results From Continuum Mechanics Analyses of the Hydraulic Fracturing Process

1980 ◽  
Vol 20 (02) ◽  
pp. 86-94 ◽  
Author(s):  
M.E. Hanson ◽  
R.J. Shaffer
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Field ◽  
Hydraulic Fracturing ◽  
Pore Pressure ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Fracturing Process

Abstract We are developing and applying theoretical, numerical models to analyze the hydraulic fracturing process. Applications include fracturing near process. Applications include fracturing near interfaces, effects of existing fractures near interfaces, pore-pressure effects, and stress-field changes due to pore-pressure effects, and stress-field changes due to embedded lenses. For a well-bonded interface, the calculations indicate that the stress-intensity factor of the leading crack tip decreases as the crack approaches a higher modulus material. As the tip crosses the interface into the higher modulus material, the stress-intensity factor abruptly increases to a higher value than it had in the lower modulus material. When the situation is reversed, the intensity factor increases as the tip approaches the interface and then abruptly decreases when the tip crosses the interface. Further calculations show that when existing cracks are present near the interface, the effects of the change in material properties across the bonded interface are reduced. In addition, our analysis shows that increases in pore pressure clue to leakage of fluids from the fracture into the surrounding media causes the stress-intensity factor to drop; a decrease in the stress-intensity factor means a reduction in the tendency to break. In other calculations we analyzed the stress-field disturbance caused by lenses of one material that are embedded in another material. These calculations show that in regions that are not tectonically relaxed, the stress field is modified by the lenses. We conclude that the fracture geometry is modified by the presence of embedded lenses under these conditions. Introduction Hydraulic fracturing and a variant - massive hydraulic fracturing (MHF) - are primary candidates for stimulating production from tight gas reservoirs in the U.S. Hydraulic fracturing has been used as a well completion technique for about 30 years, with more than 750,000 applications. MHF is a recent application, differing from hydraulic fracturing in that much larger quantities of fluid and proppant are pumped to create extensive fractures in proppant are pumped to create extensive fractures in the reservoir. Application of MHF to increase production from tight gas reservoirs has provided production from tight gas reservoirs has provided mixed and, in many cases, disappointing results.For hydraulic fracturing or MHF to be successful in enhancing the production of gas from tight reservoirs, it is important that the fractures be emplaced in productive reservoir rock providing large drainage surfaces and conductive channels back to the wellbore. Hydraulic fracturing, when used as the standard well completion technique, results in fractures driven into the formation to overcome damage due to drilling. Although the concept of MHF is to drive extensive fractures in the reservoir, we are faced with the problem of containing those fractures in a given formation. There are several reservoir properties that have been proposed as having an effect on the control of the created fracture geometry. These include the in-situ stresses, stratigraphic layering, and preexisting faults and fractures.From theories implied and demonstrated, hydraulic fractures propagate perpendicular to the least principal stress. Hence, the azimuthal orientation of the fracture is controlled approximately by the in-situ stress field. We also know that, except for very shallow applications, the created hydraulic fractures will be primarily vertical. The vertical gradient in the horizontal stresses also could be a factor in the control of the shape or vertical extent of the fractures. P. 86

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