Laboratory Study of Lost Circulation Materials for Use in Oil-Base Drilling Muds

Summary Wellbore tensile failure is a known consequence of drilling with excessive mud weight, which can cause costly events of lost circulation. Despite the successful use of lost-circulation materials (LCMs) in treating lost-circulation events of the drilling operations, extensions of wellbore-stability models to the case of a fractured and LCM-treated wellbore have not been published. This paper presents an extension of the conventional wellbore-stability analysis to such circumstances. The proposed wellbore geomechanics solution revisits the criteria for breakdown of a fractured wellbore to identify an extended margin for the equivalent circulation density (ECD) of drilling. An analytical approach is taken to solve for the related multiscale and nonlinear problem of the three-way mechanical interaction between the wellbore, fracture wings, and LCM aggregate. The criteria for unstable propagation of existing near-wellbore fractures, together with those for initiating secondary fractures from the wellbore, are obtained. Results suggest that, in many circumstances, the occurrence of both incidents can be prevented, if the LCM blend is properly engineered to recover certain depositional and mechanical properties at downhole conditions. Under such optimal design conditions, the maximum ECD to which the breakdown limit of a permeable formation could be enhanced is predicted.

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Laboratory Study on Core Fracturing Simulations for Wellbore Strengthening

Geofluids ◽

10.1155/2019/7942064 ◽

2019 ◽

Vol 2019 ◽

pp. 1-18 ◽

Cited By ~ 3

Author(s):

Biao Ma ◽

Xiaolin Pu ◽

Zhengguo Zhao ◽

Hao Wang ◽

Wenxin Dong

Keyword(s):

Bearing Capacity ◽

Laboratory Study ◽

Drilling Fluid ◽

Drilling Fluids ◽

Lost Circulation ◽

The Core ◽

Fracture Pressure ◽

Fluid Systems ◽

Fracturing Process ◽

Wellbore Strengthening

The lost circulation in a formation is one of the most complicated problems that have existed in drilling engineering for a long time. The key to solving the loss of drilling fluid circulation is to improve the pressure-bearing capacity of the formation. The tendency is to improve the formation pressure-bearing capacity with drilling fluid technology for strengthening the wellbore, either to the low fracture pressure of the formation or to that of the naturally fractured formation. Therefore, a laboratory study focused on core fracturing simulations for the strengthening of wellbores was conducted with self-developed fracture experiment equipment. Experiments were performed to determine the effect of the gradation of plugging materials, kinds of plugging materials, and drilling fluid systems. The results showed that fracture pressure in the presence of drilling fluid was significantly higher than that in the presence of water. The kinds and gradation of drilling fluids had obvious effects on the core fracturing process. In addition, different drilling fluid systems had different effects on the core fracture process. In the same case, the core fracture pressure in the presence of oil-based drilling fluid was less than that in the presence of water-based drilling fluid.

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Smart lost circulation materials for productive zones

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-018-0458-z ◽

2018 ◽

Vol 9 (1) ◽

pp. 281-296 ◽

Cited By ~ 8

Author(s):

Ahmed Mansour ◽

Arash Dahi Taleghani ◽

Saeed Salehi ◽

Guoqiang Li ◽

C. Ezeakacha

Keyword(s):

Lost Circulation ◽

Lost Circulation Materials

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Shape Memory Polymers as Lost Circulation Materials for Sealing Wide-Opened Natural Fractures

SPE Drilling & Completion ◽

10.2118/205514-pa ◽

2021 ◽

pp. 1-12

Author(s):

Maryam Tabatabaei ◽

Arash Dahi Taleghani ◽

Guoqiang Li ◽

Tianyi Zhang

Keyword(s):

Shape Memory ◽

Oil And Gas ◽

Shape Memory Polymers ◽

Reservoir Temperature ◽

Lost Circulation ◽

Drilling Equipment ◽

Order Of Magnitude ◽

X Ray Computed ◽

Large Width ◽

Lost Circulation Materials

Summary While there have been various lost circulation materials (LCMs) available in the market for treating fractures during the drilling of oil and gas wells, there is still a demand for a technology to seal large fractures. Considering limitations on the size of the particles that can be circulated through the drilling equipment, especially the bottomhole assembly, simply enlarging conventional LCM particles becomes ineffective for sealing large vugs and fractures. In this study, we use shape memory polymers (SMPs) to prepare programmed LCMs with various temporary shapes, which can transform to their permanent shapes with much larger dimensions as compared to their temporary shapes. A series of steps for thermomechanical programming of SMP is designed to trigger their expansion at the reservoir temperature. The dimensions of the programmed shapes can be an order of magnitude smaller than the ones for the original shapes, making their transport through the flowlines feasible, and bridging wide-opened fractures possible. The basic idea is that, after recovery, the SMP-based LCMs form an entangled network across a large width of fracture, and SMP particles recovered within the network, filling in the pores to form an effective sealing. We seek the capability of entangled ladders and interwoven fibers in forming a network across the fracture. A permeability plugging apparatus (PPA) is used to examine the efficiency of developed LCMs. The technique of 3D X-ray computed tomography (CT) is used to visualize the internal structure of formed plugs, enabling us to understand the mechanisms of bridging, plugging, and sealing.

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

SPE Drilling & Completion ◽

10.2118/209201-pa ◽

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.

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Risk Planning and Mitigation in Oil Well Fields

International Journal of Risk and Contingency Management ◽

10.4018/ijrcm.2015100103 ◽

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.

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