An Experimental Investigation of Filtercake Reinforced Wellbore Strengthening and Fracture Sealing

2019 ◽  
Author(s):  
Mingzheng Yang ◽  
Yuanhang Chen ◽  
Frederick B. Growcock ◽  
Feifei Zhang
Keyword(s):  
Experimental Investigation ◽  
Critical Role ◽  
Fracture Initiation ◽  
Fluid Loss ◽  
Lost Circulation ◽  
Fracture Sealing ◽  
Sealing Pressure ◽  
Wellbore Strengthening ◽  
Mud Loss ◽  
Lost Circulation Materials

Abstract Drilling-induced lost circulation should be managed before and during fracture initiation rather than after they propagate to form large fractures and losses become uncontrollable. Recent studies indicated the potentially critical role of filtercake in strengthening the wellbore through formation of a pressure-isolating barrier, as well as plugging microfractures during fracture initiation. In this study, an experimental investigation was conducted to understand the role played by filtercake in the presence of lost circulation materials (LCMs). A modified permeability plugging apparatus (PPA) with slotted discs was used to simulate whole mud loss through fractures of known width behind filtercake. Cumulative fluid loss upon achieving a complete seal and the maximum sealing pressure were measured to evaluate the combined effects of filtercake and LCMs in preventing and reducing fluid losses. The effects of some filtercake properties (along with LCM type, concentration and particle size distribution) on filtercake rupture and fracture sealing were investigated. The results indicate that filtercake can accelerate fracture sealing and reduce total mud loss. Efficiently depositing filtercake while drilling can reduce the concentration of LCM that is required to plug and isolate incipient fractures.

Quantification of the Effects of Filtercake on Wellbore Strengthening: Filtercake Rupture Resistance and Fracture Sealing Time

2019 ◽  
Author(s):  
Mingzheng Yang ◽  
Yuanhang Chen ◽  
Frederick B. Growcock
Keyword(s):  
Yield Strength ◽  
Time Pressure ◽  
Critical Role ◽  
Fracture Initiation ◽  
Fluid Loss ◽  
Drilling Fluids ◽  
Shear Yield ◽  
Fracture Sealing ◽  
Lower Permeability ◽  
Wellbore Strengthening

Abstract Wellbore strengthening (WBS) has proven to be an effective method for expanding the pressure windows of drilling operations. Recent research on WBS disclosed the critical role of filtercake in sealing microfractures during the initial stages of fracture initiation and propagation. In this study, a new parameter — “filtercake rupture resistance” — is proposed to simplify the quantitation of the filtercake’s potential to withstand pressure over a small fracture. A modified permeability plugging apparatus (PPA) was used to experimentally simulate the processes of filtercake rupture over a fracture on the wellbore wall and fracture sealing. The effects of filtercake thickness (permeability), filtercake yield strength in shear, and concentration of bentonite and a fine fibrous LCM on filtercake rupture resistance were investigated, along with the effects of these parameters on the effectiveness of filtercake in reducing fracture sealing time. Pressure spikes and fluctuations were observed when applying differential pressure across the filtercakes after formation of the cake. Filtercake of lower permeability and higher shear yield strength produce greater filtercake rupture resistance and shorter fracture sealing time. These results can be used to guide drilling fluids design for improved control of fluid loss.

Assessment of Lost Circulation Material Particle-Size Distribution on Fracture Sealing: A Numerical Study

2022 ◽  
pp. 1-15
Author(s):  
Lu Lee ◽  
Arash Dahi Taleghani
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Numerical Study ◽  
Fluid Loss ◽  
Material Particle ◽  
Lost Circulation ◽  
Fracture Sealing ◽  
Discrete Element Methods ◽  
Lost Circulation Materials

Summary Lost circulation materials (LCMs) are essential to combat fluid loss while drilling and may put the whole operation at risk if a proper LCM design is not used. The focus of this research is understanding the function of LCMs in sealing fractures to reduce fluid loss. One important consideration in the success of fracture sealing is the particle-size distribution (PSD) of LCMs. Various studies have suggested different guidelines for obtaining the best size distribution of LCMs for effective fracture sealing based on limited laboratory experiments or field observations. Hence, there is a need for sophisticated numerical methods to improve the LCM design by providing some predictive capabilities. In this study, computational fluid dynamics (CFD) and discrete element methods (DEM) numerical simulations are coupled to investigate the influence of PSD of granular LCMs on fracture sealing. Dimensionless variables were introduced to compare cases with different PSDs. We validated the CFD-DEM model in reproducing specific laboratory observations of fracture-sealing experiments within the model boundary parameters. Our simulations suggested that a bimodally distributed blend would be the most effective design in comparison to other PSDs tested here.

scholarly journals Mitigation of Lost Circulation in Oil-Based Drilling Fluids Using Oil Absorbent Polymers

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2020 ◽  
Author(s):  
Hanyi Zhong ◽  
Guangcheng Shen ◽  
Peng Yang ◽  
Zhengsong Qiu ◽  
Junbin Jin ◽  
...  
Keyword(s):  
Suspension Polymerization ◽  
Fluid Loss ◽  
Drilling Fluids ◽  
Fluid Viscosity ◽  
Lost Circulation ◽  
Fracture Sealing ◽  
Oil Absorbent ◽  
Lost Circulation Materials ◽  
Filtration Properties ◽  
Absorbent Polymer

In order to mitigate the loss circulation of oil-based drilling fluids (OBDFs), an oil-absorbent polymer (OAP) composed by methylmethacrylate (MMA), butyl acrylate (BA), and hexadecyl methacrylate (HMA) was synthesized by suspension polymerization and characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and scanning electronic microscopy (SEM). The oil-absorptive capacity of OAP under different solvents was measured as the function of temperature and time. The effect of the OAP on the rheological and filtration properties of OBDFs was initially evaluated, and then the sealing property of OAP particles as lost circulation materials (LCMs) was examined by a high-temperature and high-pressure (HTHP) filtration test, a sand bed filtration test, a permeable plugging test, and a fracture sealing testing. The test results indicated that the addition of OAP had relatively little influence on the rheological properties of OBDF at content lower than 1.5 w/v % but increased the fluid viscosity remarkably at content higher than 3 w/v %. It could reduce the HTHP filtration and improve the sealing capacity of OBDF significantly. In the sealing treatment, after addition into the OBDF, the OAP particles could absorb oil accompanied with volume enlargement, which led to the increase of the fluid viscosity and slowing down of the fluid loss speed. The swelled and deformable OAP particles could be squeezed into the micro-fractures with self-adoption and seal the loss channel. More important, fluid loss was dramatically reduced when OAP particles were combined with other conventional LCMs by a synergistic effect.

Risk Planning and Mitigation in Oil Well Fields

2015 ◽  
Vol 4 (4) ◽  
pp. 27-48
Author(s):  
Nediljka Gaurina-Međimurec ◽  
Borivoje Pašić ◽  
Petar Mijić
Keyword(s):  
Preventive Measures ◽  
Drilling Fluid ◽  
Oil Well ◽  
Remedial Measures ◽  
Successful Management ◽  
Lost Circulation ◽  
Wellbore Strengthening ◽  
Lost Circulation Materials ◽  
Industry Experience ◽  
Tools And Methods

Lost circulation presents one of the major risks associated with drilling. The complete prevention of lost circulation is impossible but limiting circulation loss is possible if certain precautions are taken. Industry experience has proved that is often easier and more effective to prevent the occurrence of loss than to attempt to stop or reduce them once they have started. The problem of lost circulation was magnified considerably when operators began drilling deeper and/or depleted formations. A strategy for successful management of lost circulation should include preventative (best drilling practices, drilling fluid selection, and wellbore strengthening materials) and remedial measures when lost circulation occurs through the use of lost circulation materials. In this paper the authors present lost circulation zones and causes, potential zones of lost circulation, excessive downhole pressures causes, preventive measures, tools and methods for locating loss zones and determining the severity of loss, lost circulation materials, and recommended treatments.

An Experimental Evaluation of the Effects of Filtercake in Wellbore Strengthening: Filtercake Rupture Resistance and Fracture Sealing Time

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Mingzheng Yang ◽  
Yuanhang Chen
Keyword(s):  
Drilling Fluid ◽  
Experimental Tests ◽  
Fracture Initiation ◽  
Vital Role ◽  
Fracture Sealing ◽  
Initiation Stage ◽  
Induced Fractures ◽  
Wellbore Strengthening ◽  
New Criterion

Abstract Recent research studies have indicated that filtercakes play a role in preventing fracture initiation, blocking pre-existing narrow fractures, and isolating drilling-induced fractures at the initiation stage. The ability of the filtercakes to effectively strengthen the wellbore expectedly depends on its capability in maintaining its integrity and providing the barrier to isolate pressure and fluid transmission between the wellbore and fractures. In this research, a modified permeability apparatus was used to evaluate the quality of drilling fluid filtercakes. A new criterion defined as filtercake rupture resistance is proposed to characterize the filtercake quality regarding its ability to sustain pressure over an open fracture. Experimental tests were conducted to investigate how filtercake thickness and filtercake yield strength affect the rupture resistance. The mechanism of filtercake in sealing the narrow fractures is explored, and it was observed that solid's plugging/bridging plays the vital role in this mechanism. A thicker and stronger filtercake also contributes to a faster establishment of complete fracture seal. The results of this research can be utilized as a reference that guides the optimization of drilling fluid for continuously strengthening the wellbore.

scholarly journals Simulating Fracture Sealing by Granular LCM Particles in Geothermal Drilling

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4878
Author(s):  
Lu Lee ◽  
Arash Dahi Taleghani
Keyword(s):  
Elevated Temperatures ◽  
Solid Particles ◽  
Fluid Viscosity ◽  
Lost Circulation ◽  
Fracture Sealing ◽  
Typical Treatment ◽  
Well Abandonment ◽  
Fracture Apertures ◽  
Geothermal Drilling ◽  
Lost Circulation Materials

Lost circulation occurs when the returned fluid is less than what is pumped into the well due to loss of fluid to pores or fractures. A lost-circulation event is a common occurrence in a geothermal well. Typical geothermal reservoirs are often under-pressured and have larger fracture apertures. A severe lost-circulation event is costly and may lead to stuck pipe, well instability, and well abandonment. One typical treatment is adding lost-circulation materials (LCMs) to seal fractures. Conventional LCMs fail to properly seal fractures because their mechanical limit is exceeded at elevated temperatures. In this paper, parametric studies in numerical simulations are conducted to better understand different thermal effects on the sealing mechanisms of LCMs. The computational fluid dynamics (CFDs) and the discrete element method (DEM) are coupled to accurately capture the true physics of sealing by granular materials. Due to computational limits, the traditional Eulerian–Eulerian approach treats solid particles as a group of continuum matter. With the advance of modern computational power, particle bridging is achievable with DEM to track individual particles by modeling their interactive forces between each other. Particle–fluid interactions can be modeled by coupling CFD algorithms. Fracture sealing capability is investigated by studying the effect of four individual properties including fluid viscosity, particle size, friction coefficient, and Young’s modulus. It is found that thermally degraded properties lead to inefficient fracture sealing.

Experimental Investigation and Modeling of Mudcake Buildup Inside Fractures and the Resulting Fracture Isolation

SPE Journal ◽  
2019 ◽  
Vol 24 (06) ◽  
pp. 2929-2945
Author(s):  
Hamza A. Jaffal ◽  
Kenneth E. Gray ◽  
Chadi S. El Mohtar
Keyword(s):  
Experimental Investigation ◽  
Experimental Validation ◽  
Recent Literature ◽  
Basic Physics ◽  
Fracture Sealing ◽  
Wellbore Strengthening

Summary The role of mudcake buildup in fracture sealing and wellbore strengthening has been observed and documented in recent literature. However, there is a gap in the literature when it comes to fully understanding the mechanism of mudcake buildup, whether inside the fracture or at its mouth. This study presents an extension to a previously developed model, along with experimental validation, for mudcake buildup at the wellbore wall to capture the basic physics of mudcake buildup inside fractures and the resulting fracture sealing.

Modeling Lost Circulation Through Drilling-Induced Fractures

SPE Journal ◽  
2017 ◽  
Vol 23 (01) ◽  
pp. 205-223 ◽  
Author(s):  
Yongcun Feng ◽  
K. E. Gray
Keyword(s):  
Loss Rate ◽  
Fluid Loss ◽  
Operational Parameters ◽  
Fracture Width ◽  
Pressure Losses ◽  
Lost Circulation ◽  
Wellbore Pressure ◽  
Induced Fractures ◽  
Wellbore Strengthening ◽  
Viscous Pressure

Summary Previous lost-circulation models assume either a stationary fracture or a constant-pressure- or constant-flowrate-driven fracture, but they cannot capture fluid loss into a growing, induced-fracture driven by dynamic circulation pressure during drilling. In this paper, a new numerical model is developed on the basis of the finite-element method for simulating this problem. The model couples dynamic mud circulation in the wellbore and induced-fracture propagation into the formation. It provides estimates of time-dependent wellbore pressure, fluid-loss rate, and fracture profile during drilling. Numerical examples were carried out to investigate the effects of several operational parameters on lost circulation. The results show that the viscous pressure losses in the wellbore annulus caused by dynamic circulation can lead to significant increases in wellbore pressure and fluid loss. The information provided by the model (e.g., dynamic circulation pressure, fracture width, and fluid-loss rate) is valuable for managing wellbore pressure and designing wellbore-strengthening operations.

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