Development of Twin Temperature Compensation and High-Level Biaxial Pressurization Calibration Techniques for CSIRO In-Situ Stress Measurement in Depth

Li, Yuan; Fu, Shuangshuang; Li, Qiao; Liu, Zibin; Zhang, Yihai

doi:10.1007/s00603-018-1618-7

Cited by 12 publications

(10 citation statements)

References 10 publications

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“…The effect on stress trend is less, varying by only a few degrees. Another factor is temperature which significantly impacts overcore measurements, leading to the development of temperature compensation tools (Cai 1991;Li et al 2019).…”

Section: Relief Methodsmentioning

confidence: 99%

In situ stress data management and analysis: implications for numerical modelling

Musolino¹,

Chester²,

Ford³

2022

Caving 2022: Fifth International Conference on Block and Sublevel Caving

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The measurement of in situ stresses is a costly and time intensive procedure, requiring significant experience, diligence and planning to obtain reliable results. Therefore, it is important to have good data management and analysis to maintain investment costs and reduce estimate uncertainty. Geotechnical design considerations rely on accurate estimates of the stress regime to predict subsurface rock behaviour. Some uses include cave deconfinement, cave preconditioning, planning drive orientation and ground support design. Two simple numerical models are presented. The first demonstrates stress redistribution around a cave zone and how it may influence optimal crusher chamber placement. The second model is of an undercut level and the stress experienced by the drawbell drives below. The models demonstrate the impact of in situ stress uncertainty, with potential consequences for design decisions by altering the stress trend and plunge. Currently, pragmatic workflows are not publicly available that holistically detail the key steps in in situ stress data analysis. In addition, rarely are end-users of the data demonstrated the uncertainty in the values provided. Instead, they are presented with a single stress average gradient and trend. This manuscript offers a workflow for those embarking on in situ stress testing campaigns and serves as a tool to communicate the complexities to potential end-users. The workflow utilises the Euclidian mean rather than scalar averaging of the stress tensor and relates 'loading methods' (hydrofracking) and 'other' (borehole breakout observations) methods of stress estimation with the full tensor resolved from relief methods (overcore and acoustic emissions). A software application within the mXrap suite is presented as a potential aid to stress data management and analysis. Implications of stress uncertainty are demonstrated and discussed concerning design, expected induced fracture orientations, and future workflow enhancements. The numerical models indicate optimal placement for a crusher chamber around a simulated cave zone was observed to be in the orientation of SHmax. Increasing the stress field plunge by 20° impacted optimal crusher placement. The second numerical model demonstrates that a rotation of the horizontal stress trend by 20° has noticeable impact on the differential stress in the backs of a tunnel where drawbells will be created, this has implications for planning the undercut veranda length.

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Section: Relief Methodsmentioning

confidence: 99%

In situ stress data management and analysis: implications for numerical modelling

Musolino¹,

Chester²,

Ford³

2022

Caving 2022: Fifth International Conference on Block and Sublevel Caving

View full text Add to dashboard Cite

show abstract

“…In addition, sometimes the strain gauges are not directly bonded to one material but to multiple composite materials, in which case the strain gauges are subject to the coupling effects of multiple materials. For example, in the CSIRO method for in situ stress measurements, developed by our research team [32], strain gauges were pasted on a composite of adhesive layer and rock, where the thickness of the adhesive layer had an effect on the thermal output.…”

Section: Analysis Of the Error Caused By The Thickness Of An Adhesive...mentioning

confidence: 99%

Calibration Experiment and Temperature Compensation Method for the Thermal Output of Electrical Resistance Strain Gauges in Health Monitoring of Structures

Jin

Fan

et al. 2023

Symmetry

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Electrical resistance strain gauges are widely used in asymmetric structures for measurement and monitoring, but their thermal output in changing temperature environments has a significant impact on the measurement results. Since thermal output is related to the coefficient of thermal expansion of the strain gauge’s sensitive grating material and the measured object, the temperature self-compensation technique of strain gauges fails to eliminate the additional strain caused by temperature because it cannot match the coefficient of thermal expansion of various measured objects. To address this problem, in this study, the principle of the thermal output of electrical resistance strain gauges was analyzed, a calibration experiment for thermal output in the case of a mismatch between the coefficient of linear expansion of the measured object and the strain gauge grating material was conducted, and the mechanism for temperature influence on thermal output was revealed. A method was proposed to obtain the thermal output curves for different materials by using thermostats with dual temperatures to conduct temperature calibration experiments. A linear regression method was used to obtain a linear formula for the thermal output corresponding to each temperature. The thermal output conversion relationship was derived for materials with different coefficients of linear expansion. An in situ temperature compensation technique for electrical resistance strain gauges that separates the measured strain into thermal and mechanical strains was proposed. The results showed that the thermal output curve for the measured object can be calibrated in advance and then deducted from the measured strain, thus reducing the influence of temperature-induced additional strain on the mechanical strain. In addition, a new method was provided for the calculation of the thermal output among materials with similar coefficients of linear expansion, providing a reference for the health monitoring of asymmetric structures.

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“…The rock stress in the formation is mainly formed by gravity and tectonic stresses induced by drilling, slotting, and coring (Li et al, 2019). The geomechanical model is established in the early stage of the oil and gas field development, which can address various problems encountered in the life cycle of oil and gas reservoir development.…”

Section: Introductionmentioning

confidence: 99%

Geomechanical Modeling and Inversion Analysis of the in-situ Stress Field in Deep Marine Shale Formations: A Case Study of the Longmaxi Formation, Dingshan Area, China

Liu

Yang

et al. 2022

Front. Earth Sci.

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Based on the comprehensive analysis of wellbore characteristics in a deep shale gas field, the in-situ stress state of the shale reservoir was assessed in this study for the Longmaxi formation in the Dingshan area, Southwestern China. The data obtained from hydraulic fracturing, drilling-induced fractures, and in-situ core testing were used to determine the magnitude and direction of the maximum principal horizontal stress in five wells. Besides, hydraulic fracturing and cross-multipole array acoustic logging (XMAC) were employed to determine the vertical variation of the in-situ stress. Based on the logging interpretation and mechanical test results, the spatial distribution of rock mechanical parameters in the Dingshan area was assessed by the amplitude variation versus offset (AVO) seismic inversion. A 3D heterogeneous mechanical inversion model was realized via the ANSYS and CATIA3D finite element software packages, providing the area in-situ stress field simulation. The depth, fault strike, and position change effects on the main stress, horizontal stress difference, and horizontal stress difference coefficient were numerically simulated. The results show that the maximum principal stress azimuth was mainly concentrated in the NE20°-NE80° sector. Moreover, the development zone of natural fractures was related to the area with the highest principal stress differences. The maximum principal stress variation in the study area was mainly in the compressive range from −135 to −45 MPa, gradually increasing from east to west and south to north. The stress type mainly depended on the depth, fault strike, and rock mechanical parameters, while the stress difference and stress difference coefficient near the fault structure were relatively small. This study’s findings are considered instrumental in improving the borehole stability, determining the casing setting point, and optimizing the well location in deep shale reservoirs with similar geological conditions.

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Development of Twin Temperature Compensation and High-Level Biaxial Pressurization Calibration Techniques for CSIRO In-Situ Stress Measurement in Depth

Cited by 12 publications

References 10 publications

In situ stress data management and analysis: implications for numerical modelling

In situ stress data management and analysis: implications for numerical modelling

Calibration Experiment and Temperature Compensation Method for the Thermal Output of Electrical Resistance Strain Gauges in Health Monitoring of Structures

Geomechanical Modeling and Inversion Analysis of the in-situ Stress Field in Deep Marine Shale Formations: A Case Study of the Longmaxi Formation, Dingshan Area, China

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