Combined effect of anisotropy and uncertainty on the safe mud pressure window of horizontal wellbore drilled in anisotropic saturated rock

Tran, Nam H.; Phi, Duc; Vu, Minh Ngoc; Nguyen, Tien Anh; Pham, Duc Tho; Trieu, Hung Truong

doi:10.1016/j.ijrmms.2022.105061

Cited by 9 publications

(4 citation statements)

References 42 publications

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“…Due to the old geological age, deep burial, multiple tectonic movements and accumulation periods, and late transformation, the deep strata in China have complex characteristics such as a high temperature, a high-steep structure, multiple faults, a huge thick salt paste layer and a mixed gravel layer, carbonate fractures, solution pores, developed caves, great difference between pore fluid pressure and in situ stress distribution, poor regularity, and strong uncertainty. The input parameters of the borehole stability analysis model are seriously uncertain, and it is difficult to adapt the prediction results to the formation under such uncertain parameter conditions, which makes the risk problems in the drilling process more prominent, and is mainly reflected as serious borehole instability in the complex intervals, frequent occurrence of blowout loss, serious inclination of the high-steep structure, and frequent occurrence of drilling tool accidents [20,48].…”

Section: Quantitative Characterization Of Stratigraphic Heterogeneitymentioning

confidence: 99%

“…The uncertainties surrounding in situ stresses, along with those related to rock strength and deformation properties, significantly widen the range of outcomes in the probability distribution for both minimum and maximum mud weights required to prevent fracturing and cracking [38][39][40][41][42]. Given this complexity, when embarking on the development of new fields, it is advisable to adopt a deterministic approach that relies on the most reliable estimates of input parameters to ascertain borehole stability [43][44][45][46][47][48]. In this scholarly contribution, we established a risk assessment model specifically tailored to evaluate borehole stability.…”

Section: Introductionmentioning

confidence: 99%

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Risk Assessment Method for Analyzing Borehole Instability Considering Formation Heterogeneity

Gao,

Wang,

Shi

et al. 2023

Processes

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In the study of borehole instability, the majority of input parameters often rely on the average values that are treated as fixed values. However, in practical engineering scenarios, these input parameters are often accompanied by a high degree of uncertainty. To address this limitation, this paper establishes a borehole stability model considering the uncertainty of input parameters, adopts the Monte Carlo method to calculate the borehole stability reliability at different drilling fluid densities, evaluates the sensitivity of borehole instability to a single parameter, and studies the safe drilling fluid density window at different borehole stability reliability values under multi-parameter uncertainties. The results show that the uncertainty of rock cohesion has a great influence on the fracture pressure of the vertical and horizontal wells. The minimum horizontal stress has the greatest influence on the fracture pressure of the vertical and horizontal wells, followed by pore pressure. In the analysis of borehole stability, the accuracy of cohesion and minimum horizontal stress parameters should be improved. In scenarios involving multiple parameter uncertainties, while the overall trend of the analysis results remains consistent with the conventional borehole stability outcomes, there is a noteworthy narrowing of the safe drilling fluid density window. This suggests that relying on conventional borehole stability analysis methods for designing the safe drilling fluid density window can considerably increase the risks of borehole instability. Uncertainty assessment is crucial to determine the uncertainties associated with the minimum required mud pressure, thereby ensuring more informed decision-making during drilling operations. To meet practical application demands, structure and boundary condition uncertainties should be implemented for a more comprehensive assessment of borehole stability.

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Section: Quantitative Characterization Of Stratigraphic Heterogeneitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Risk Assessment Method for Analyzing Borehole Instability Considering Formation Heterogeneity

Gao,

Wang,

Shi

et al. 2023

Processes

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show abstract

“…Recently in the literature, there have been many studies on the stress state of the wellbore. Whilst Kanfar et al [7], Do et al [8,9], Tran et al [10], Khoshghalb [11,12], Ghaffaripour et al [13], and Shafee and Khoshghalb [14] relied on the hydro-mechanical behavior model, Abousleiman and Ekbote [15] and Kanfar et al [16] based on a full thermo-hydromechanical behavior model of the materials. However, these works mainly focus on the development of analytical and numerical models without emphasizing the difference in stress state around the wellbore between the cases of cooling and heating as well as different anisotropy degrees of the rocks.…”

Section: Introductionmentioning

confidence: 99%

Porothermoelastic Model for Analysis of Stress State Around Wellbores in Anisotropic Rock

Hung

2024

GEOMATE

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“…On the other hand, the low permeability of shale rock can induce undrained conditions, immediately after drilling (short term). The undrained pore fluid pressure evolution can enhance plasticity [36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Sensitivity Analysis of Wellbore Mud Pressure towards Anisotropic Shale Properties, Pore Fluid Pressure and Far Field Stresses

Deangeli,

Liu,

Yang

2023

Applied Sciences

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The paper investigates the mud pressure to maintain the stability of wellbores drilled in transversely isotropic shale through sensitivity analyses, carried out with analytical and numerical modeling (FLAC). To this end, we interpreted the anisotropic strength of the Tournemire shale with the Weakness Plane Model (WPM) and the modified Hoek–Brown criterion (HBm). The sensitivity analyses of synthetic case studies indicated a different trend in mud pressure for the two criteria. In some cases, the WPM predicts mud pressures higher than those predicted by the HBm and vice versa. The mud pressures predicted by the HBm resulted in being more sensitive to the increase in the anisotropy of the far field stresses for all the inclinations of the weakness planes. In this context, the WPM predicts some anomalous low mud pressures in a wide range of inclinations of the weak planes. The change in the frictional component of strength decreases with an increase in the pore fluid pressure for both criteria. The mud pressure predicted by the WPM resulted in being more sensitive to the change in frictional strength. The change in trend of the two criteria with change in input data suggests caution in the “a priori” selection of the strength criterion. A simple solution is proposed to predict a safe and reliable mud pressure with a small number of lab tests.

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Combined effect of anisotropy and uncertainty on the safe mud pressure window of horizontal wellbore drilled in anisotropic saturated rock

Cited by 9 publications

References 42 publications

Risk Assessment Method for Analyzing Borehole Instability Considering Formation Heterogeneity

Risk Assessment Method for Analyzing Borehole Instability Considering Formation Heterogeneity

Porothermoelastic Model for Analysis of Stress State Around Wellbores in Anisotropic Rock

Sensitivity Analysis of Wellbore Mud Pressure towards Anisotropic Shale Properties, Pore Fluid Pressure and Far Field Stresses

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