An experimental study to reduce the breakdown pressure of the unconventional carbonate rock by cyclic injection of thermochemical fluids

Tariq, Zeeshan; Mahmoud, Mohamed; Abdulraheem, Abdulazeez; Al-Nakhli, Ayman; Bataweel, Mohammed

doi:10.1016/j.petrol.2019.106859

Cited by 31 publications

(16 citation statements)

References 22 publications

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“…To study the effect of seepage force, solve the seepage force equation (Equation ( 11)). The internal and external boundary stresses are zero as the effects of wellbore pressure p a and pore pressure p b at outer boundary are already taken into account in Equation (11).…”

Section: Calculation Of Seepage Force Stress Fieldmentioning

confidence: 99%

“…Combining Equations ( 6), (11), and (12), the circumferential stress S 4 θ formed by the seepage force under the plane strain condition during the steady-state flowing of wellbore fluid into a vertical wellbore:…”

Section: Calculation Of Seepage Force Stress Fieldmentioning

confidence: 99%

“…Hubbert and Willis [5] and Medlin and Masse [6] investigated the mechanics of hydraulic fracture initiation by comparing laboratory experiments with theoretical predictions based on poroelasticity. In the recent 20 years, quite a few scholars [7][8][9][10][11] have analyzed the influencing factors of formation breakdown pressure based on Haimson's theory combined with experimental results.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore

et al. 2021

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As a fluid flows through a porous media, a drag force, called seepage force in the paper, will be formed on the matrix of the media in the fluid flowing direction. However, the seepage force is normally ignored in the analysis of wellbore fracturing during hydraulic fracturing operation. In this paper, an analytical model for seepage force around a vertical wellbore is presented based on linear elasticity theory, and the effect of the seepage force on wellbore breakdown has been analyzed. Also studied are the effects of the two horizontal principal stresses and the reservoir permeability on the action of seepage force. The paper proves that seepage force lowers formation breakdown pressure of a vertical wellbores; the deeper a formation is, the greater action of the seepage force; seepage force contributes more to breakdown formation with small difference of the two horizontal stresses such as unconventional reservoirs; seepage force increases as rock permeability decreases, and it should not be ignored in hydraulic fracturing analysis, especially for low-permeability formation.

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Section: Calculation Of Seepage Force Stress Fieldmentioning

confidence: 99%

Section: Calculation Of Seepage Force Stress Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore

et al. 2021

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“…This reaction is normally considered a green reaction because it is mainly composed of salts [ 40 , 41 ]. Due to the high-pressure temperature generation, thermochemical fluids were successfully used in the oil and gas industry for several purposes such as wax removal [ 42 ], heavy oil production [ 43 ], breakdown pressure reduction [ 44 , 45 , 46 ], increasing stimulated reservoir volume [ 47 ], and enhanced oil recovery (EOR) applications [ 48 ]. Mahmoud [ 23 ] used thermochemical fluids along with chelating agents to remove the filter cake formed by barite-weighted drilling fluids in oil- and water-based types.…”

Section: Methodsmentioning

confidence: 99%

Reduction of Breakdown Pressure by Filter Cake Removal Using Thermochemical Fluids and Solvents: Experimental and Numerical Studies

et al. 2021

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The process of well cleanup involves the removal of an impermeable layer of filter cake from the face of the formation. The inefficient removal of the filter cake imposes difficulty on fracturing operations. Filter cake’s impermeable features increase the required pressure to fracture the formation. In this study, a novel method is introduced to reduce the required breakdown pressure to fracture the formation containing the water-based drilling fluid filter cake. The breakdown pressure was tested for five samples of similar properties using different solutions. A simulated borehole was drilled in the core samples. An impermeable filter cake using barite-weighted drilling fluid was built on the face of the drilled hole of each sample. The breakdown pressure for the virgin sample without damage (filter cake) was 6.9 MPa. The breakdown pressure increased to 26.7 MPa after the formation of an impermeable filter cake. Partial removal of filter cake by chelating agent reduced the breakdown pressure to 17.9 MPa. Complete dissolution of the filter cake with chelating agents resulted in the breakdown pressure approximately equivalent to the virgin rock breakdown pressure, i.e., 6.8 MPa. The combined thermochemical and chelating agent solution removed the filter cake and reduced the breakdown pressure to 3.8 MPa. Post-treatment analysis was carried out using nuclear magnetic resonance (NMR) and scratch test. NMR showed the pore size redistributions with good communication between different pores after the thermochemical removal of filter cake. At the same time, there was no communication between the different pores due to permeability impairment after filter cake formation. The diffusion coupling through NMR scans confirmed the higher interconnectivity between different pores systems after the combined thermochemical and chelating agent treatment. Compressive strength was measured from the scratch test, confirming that filter cake formation caused added strength to the rock that impacts the rock breakdown pressure. The average compressive strength of the original specimen was 44.5 MPa that increased to 73.5 MPa after the formation of filter cake. When the filter cake was partially removed, the strength was reduced to 61.7 MPa. Complete removal with chelating agents removed the extra strength that was added due to the filter cake presence. Thermochemical and chelating agents resulted in a significantly lower compressive strength of 25.3 MPa. A numerical model was created to observe the reduction in breakdown pressure due to the thermochemical treatment of the filter cake. The result presented in this study showed the engineering applications of thermochemical treatment for filter cake removal.

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“…TCs are used to generate very-high-pressure pulses in order to fracture rocks. The pressure pulses generated by to the chemical reaction can reach more than 10,000 psi, creating complex fracture networks [ 1 ]. This method is applied to increase the stimulated reservoir volume (SRV) around hydraulic fractures in unconventional and tight reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Mass and Heat Transfer of Thermochemical Fluids in a Fractured Porous Medium

2020

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The desire to improve hydraulic fracture complexity has encouraged the use of thermochemical additives with fracturing fluids. These chemicals generate tremendous heat and pressure pulses upon reaction. This study developed a model of thermochemical fluids’ advection-reactive transport in hydraulic fractures to better understand thermochemical fluids’ penetration length and heat propagation distance along the fracture and into the surrounding porous media. These results will help optimize the design of this type of treatment. The model consists of an integrated wellbore, fracture, and reservoir mass and heat transfer models. The wellbore model estimated the fracture fluid temperature at the subsurface injection interval. The integrated model showed that in most cases the thermochemical fluids were consumed within a short distance from the wellbore. However, the heat of reaction propagated a much deeper distance along the hydraulic fracture. In most scenarios, the thermochemical fluids were consumed within 15 ft from the fracture inlet. Among other design parameters, the thermochemical fluid concentration is the most significant in controlling the penetration length, temperature, and pressure response. The model showed that a temperature increase from 280 to 600 °F is possible by increasing the thermochemical concentration. Additionally, acid can be used to trigger the reaction but results in a shorter penetration length and higher temperature response.

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An experimental study to reduce the breakdown pressure of the unconventional carbonate rock by cyclic injection of thermochemical fluids

Cited by 31 publications

References 22 publications

Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore

Effect of Seepage Force on the Wellbore Breakdown of a Vertical Wellbore

Reduction of Breakdown Pressure by Filter Cake Removal Using Thermochemical Fluids and Solvents: Experimental and Numerical Studies

Mass and Heat Transfer of Thermochemical Fluids in a Fractured Porous Medium

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