scholarly journals Sealing Mechanism Based on Force Chain and Experimental Investigation of Sealing Fractures

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Dan Bao ◽  
Chengyu Zhou ◽  
Lei Wang ◽  
Peng Zhang ◽  
Zhenfu Jia ◽  
...  
Keyword(s):  
Network Structure ◽  
Force Chain ◽  
Fluid Loss ◽  
Technological Problem ◽  
Material System ◽  
Lost Circulation ◽  
Seal Integrity ◽  
Strong Force ◽  
Sealing Zone ◽  
Sealing Mechanism

Abstract Lost circulation often occurs in fractured formations, which was a main technological problem during drilling. Conventional lost circulation material (LCM) was often used to form a plugging zone to prevent fluid loss during drilling. The formed seal was a granular material system composed of LCMs. This paper presented the physical mechanism of the force chain within the plugging zone. The seal performance is related to the properties of LCMs. A device for testing seal performance of LCMs with long fracture was developed. The effects of LCM performance on seal integrity were investigated using a plugging device with long fracture. The results showed that the wide particle size distribution (PSD) of LCMs tended to form a strong force chain network structure within the sealing zone. Increasing the stiffness and roughness of LCMs resulted in higher breaking pressure. The addition of fiber with high length-diameter ratio could improve the shear strength of the sealing zone and form a strong force chain network structure, and it can reduce 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.

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.

scholarly journals Modeling Lost-Circulation into Fractured Formation in Rock Drilling Operations

2021 ◽  
Author(s):  
Rami Albattat ◽  
Hussein Hoteit
Keyword(s):  
Analytical Modeling ◽  
Drilling Fluid ◽  
Fluid Loss ◽  
Fracture Conductivity ◽  
Type Curves ◽  
Bingham Plastic ◽  
Lost Circulation ◽  
Rock Formations ◽  
Solution Methods ◽  
Drilling Operations

Loss of circulation while drilling is a challenging problem that may interrupt drilling operations, reduce efficiency, and increases cost. When a drilled borehole intercepts conductive faults or fractures, lost circulation manifests as a partial or total escape of drilling, workover, or cementing fluids into the surrounding rock formations. Studying drilling fluid loss into a fractured system has been investigated using laboratory experiments, analytical modeling, and numerical simulations. Analytical modeling of fluid flow is a tool that can be quickly deployed to assess lost circulation and perform diagnostics, including leakage rate decline and fracture conductivity. In this chapter, various analytical methods developed to model the flow of non-Newtonian drilling fluid in a fractured medium are discussed. The solution methods are applicable for yield-power-law, including shear-thinning, shear-thickening, and Bingham plastic fluids. Numerical solutions of the Cauchy equation are used to verify the analytical solutions. Type-curves are also described using dimensionless groups. The solution methods are used to estimate the range of fracture conductivity and time-dependent fluid loss rate, and the ultimate total volume of lost fluid. The applicability of the proposed models is demonstrated for several field cases encountering lost circulations.

Study on force-chain-resistance network structure of pressure control granular material

2021 ◽  
Author(s):  
Yuhao Zhu ◽  
Enyuan Dong ◽  
Yu Zhu ◽  
Yongxing Wang ◽  
Sheng Yin
Keyword(s):  
Granular Material ◽  
Network Structure ◽  
Pressure Control ◽  
Force Chain ◽  
Resistance Network

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.

scholarly journals Quantitative Study on the Contact Force and Force Chain Characteristics of Ore Particle Systems during Ore Drawing from a Single Drawpoint under the Influence of a Flexible Barrier

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qingfa Chen ◽  
Shikang Qin ◽  
Shiwei Wu
Keyword(s):  
Contact Force ◽  
Particle System ◽  
Vertical Direction ◽  
Particle Systems ◽  
Force Chain ◽  
Contact Network ◽  
Normal Contact ◽  
Strong Force ◽  
Flexible Barrier ◽  
Initial Stage

It is of great significance to carry out quantitative research on the contact force chain characteristics of ore particle systems during ore drawing to reveal the microscopic and mesoscopic characteristics of ore particle systems during implementation of the synchronous filling shrinkage stoping method. Based on the particle discrete element method, combined with the relevant knowledge of contact mechanics and statistical mechanics, microscopic properties of the ore particle system were studied quantitatively. (1) The probability distributions of the normal and tangential contact forces during ore drawing from a single drawpoint under a flexible barrier are similar, and both show exponential decay. (2) In the regions on both sides of the model, the ore particles will not be released because they are far from the drawpoint; there, the coordination number is stable, and the density of contact network is large. In the upper part of the drawpoint, ore particles flow, the coordination number fluctuates violently, and the density of contact network is small. (3) In the initial stage, the stress distribution of the ore particle system is uniform, and the strong force chain does not show obvious directivity. After that, the directions of the strong force chains in the ore particle system are inclined to the vertical direction, and the strong force chains mainly bear the load in the vertical direction. (4) In the initial stage of drawing, the normal contact force is mainly concentrated in the vertical direction. With the progression of drawing, the normal contact force at an angle of 30° to the horizontal direction increases gradually, and the number of the main direction of the average contact force distribution changes from one to three (the vertical direction and the direction with a ±30° angle to the horizontal direction).

scholarly journals Numerical Evaluation of CFD-DEM Coupling Applied to Lost Circulation Control: Effects of Particle and Flow Inertia

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Marcos V. Barbosa ◽  
Fernando C. De Lai ◽  
Silvio L. M. Junqueira
Keyword(s):  
Density Ratio ◽  
Petroleum Industry ◽  
Particle Diameter ◽  
Vertical Channel ◽  
Solid Particles ◽  
Fluid Loss ◽  
Discrete Phase Model ◽  
Particle Injection ◽  
Lost Circulation ◽  
Channel Bottom

In the present study, the transport and deposition of solid particles to mitigate the loss circulation of fluid through a fracture transversely placed to a vertical channel is numerically investigated. These solid particles (commonly known in the industry as lost circulation materials—LCMs) are injected into the flow during the drilling operation in the petroleum industry, in hopes to control the fluid loss. The numerical simulation of the process follows a two-stage process: the first characterizes the lost circulation flow and the second the particle injection. The numerical model comprises an Eulerian–Lagrangian approach, in which the dense discrete phase model (DDPM) is combined with the discrete element method (DEM). A parametric analysis is done by varying the vertical channel Reynolds number, the particle-to-fluid density ratio, and the particle diameter. Results are shown in terms of the particle’s bed geometric characteristics, focusing on the location inside the fracture where the particles deposit, and the particle bed length, height, and time spent to fill the fracture. Also monitored are the fluid loss reduction over time and the fractured channel bottom pressure (which can be related to the fracture pressure). Results indicate that using a slow/intermediate flow velocity, associated with heavy particles with small diameters, provides the best combination for the efficient mitigation of the fluid loss process.

High-Fluid-Loss, High-Strength Lost Circulation Treatments

2010 ◽  
Author(s):  
Mark W. Sanders ◽  
Jason Thomas Scorsone ◽  
James E. Friedheim
Keyword(s):  
High Strength ◽  
Fluid Loss ◽  
Lost Circulation ◽  
High Fluid
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