The failure behaviour of poorly cemented sands at a borehole wall using laboratory tests

Hashemi, S.S.; Melkoumian, N.; Taheri, Abbas; Jaksa, M.

doi:10.1016/j.ijrmms.2015.03.037

Cited by 12 publications

(11 citation statements)

References 28 publications

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“…The increase in the water content resulted in strength reduction because of the increased total porosity. This outcome agrees with previous studies by Hashemi et al [3] conducted on synthetic sandstones with 10% water content.…”

Section: Ucs Test Results On Solid Specimenssupporting

confidence: 93%

“…As a result, sophisticated methods have been proposed by various researchers to make realistic synthetic poorly cemented sandstone samples for testing [21,23]. Synthetic rock specimens are commonly used as an alternative for natural rocks for conducting laboratory-based borehole stability experiments [3]. The preparation of synthetic rocks involves mixing sand grains, a cementing agent and water.…”

Section: Sample Preparation and Propertiesmentioning

confidence: 99%

“…To prepare synthetic sandstone samples with reasonably homogeneous properties, it is important to establish and follow a consistent sample preparation procedure. The synthetic sandstone specimens used in this study were prepared according to the mixture preparation procedure for a poorly cemented formation proposed by Hashemi et al [3]. The mixture was composed of natural silica sands with two different grain size ranges, namely, coarse grain sands with a grain size between 0.425mm-1.4mm, and fine grain sands with a grain size between 0.15mm-0.355mm, Portland cement type II (specific gravity, GS=3.15g/cm³) and water.…”

Section: Aes000553 3(1)2022mentioning

confidence: 99%

“…It has been estimated that about 70% of the world's hydrocarbon reservoirs are found within poorly cemented formations, where borehole instabilities are most likely to occur [2]. Furthermore, a significant number of exploration boreholes being drilled through poorly cemented formations worldwide, and particularly in Australia, often result in technical difficulties such as stuck pipes [3]. Borehole instability problems typically account for 5-10% of the total drilling costs and add up to the annual cost of hundreds of millions of dollars worldwide [4].…”

Section: Introductionmentioning

confidence: 99%

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Laboratory Studies on the Application of Convergence Measuring Device for Monitoring Borehole Deformation

Heo¹

2022

AES

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Borehole convergence or the change in borehole diameter during or after drilling is one of the primary indicators of borehole instability. Early recognition of borehole instability is critical in achieving successful and timely completion of drilling operations and for borehole exploitation. Commonly used borehole monitoring devices, such as the caliper log and the acoustic borehole televiewer, provide continuous measurement of the borehole diameter when drilling into subsurface formations. However, limited attempts have been made to accurately measure the borehole diameter changes in laboratoryscale studies. In this study, series of laboratory experiments were conducted on Thick-Walled Hollow Cylinder (TWHC) specimens made of synthetic poorly cemented sandstone, where a new laboratory-scale Convergence Measuring Device (CMD) was deployed inside the borehole for monitoring the deformation of the borehole walls. This new CMD was developed based on the concept of Local Deformation Transducer (LDT). Three different cement contents (i.e., 10%, 12%, and 14%) and various lateral confining stress conditions (i.e., 2 MPa, 4 MPa and 6 MPa) were considered to evaluate the performance of the CMD. The specimens with CMD were tested using a modified Hoek cell which enabled visual monitoring of the borehole convergence and borehole wall breakout processes during the tests. The results showed that the CMD was capable of accurately measuring the borehole deformation. Visual monitoring of the borehole allowed precise identification of the locations and shapes of the borehole wall breakouts. Studies showed that the amount of the cement content and the magnitude of the lateral confining stress have a significant effect on the borehole deformation and failure stress. Furthermore, it was observed that the rate of increase in the radial strain of the TWHC specimens prior to the initiation of a borehole wall failure decreases when the cement content was increased.

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Section: Ucs Test Results On Solid Specimenssupporting

confidence: 93%

Section: Sample Preparation and Propertiesmentioning

confidence: 99%

Section: Aes000553 3(1)2022mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Laboratory Studies on the Application of Convergence Measuring Device for Monitoring Borehole Deformation

Heo¹

2022

AES

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“…[19][20][21][22]. In case of having an improved layer over a weak soil, once failure occurs, the failure undergoes tensile cracks in the bottom of the stabilized layer; hence, tensile strength estimation becomes a necessity.…”

Section: Introductionmentioning

confidence: 99%

Parameters Controlling Tensile Strength of Zeolite-Cemented Sands

Khajeh¹,

MolaAbasi

Semsani³

2017

Scientia Iranica

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Abstract. Treating soil with cement and zeolite is widely used in soil stabilization. This research intends to quantify the impact of cement and zeolite contents, porosity index, and voids/cement ratio on zeolite cemented sands by the splitting tensile strength (t) assessment. The approach of splitting tensile tests using specimens by di erent zeolite replacement percentages was followed. Results indicated that cement was replaced by zeolite at optimum proportion of 30%. Then, improved values of t by the e ect of zeolite and cement chemical properties in the cement sand specimens were attained. Zeolite can have a more signi cant e ect on a compacted mixture if its cement content and porosity increase. In this paper, it is shown that for the zeolite cemented sands, t increases by increase in cement content (C) and reduction in porosity (n); and a power function is welladapted to t both t C and t n. Afterwards, good correlations are obtained between voids/cement ratio (n=c) and the splitting tensile strength ( t ) of the sand-zeolite-cement studied. Finally, based on a number of input variables, namely, porosity (n), replacement of cement by zeolite (Z), and cement content (C), considering the regression approach, an equation is suggested to predict t. Moreover, it is shown that the evolved equation could successfully predict the tensile strength.

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Investigation on the Environmental Impact of Soil Improvement Techniques: Comparison of Cement Grouting and Biocement

Naeimi¹,

Haddad

2018

Proceedings of GeoShanghai 2018 International Conference: Geoenvironment and Geohazard

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The failure behaviour of poorly cemented sands at a borehole wall using laboratory tests

Cited by 12 publications

References 28 publications

Laboratory Studies on the Application of Convergence Measuring Device for Monitoring Borehole Deformation

Laboratory Studies on the Application of Convergence Measuring Device for Monitoring Borehole Deformation

Parameters Controlling Tensile Strength of Zeolite-Cemented Sands

Investigation on the Environmental Impact of Soil Improvement Techniques: Comparison of Cement Grouting and Biocement

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