Probabilistic Assessment of the Temperature-Induced Effective Fracture Pressures

Kinik, Koray; Wojtanowicz, Andrew K.; Gumus, Ferhat

doi:10.2118/170316-pa

Cited by 3 publications

(4 citation statements)

References 58 publications

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“…According to Equations (21)- (25), the TVD, the gravitational acceleration (g) and the critical failure point A (θ max ) are usually certain, while the vertical stress (σ v ), maximum horizontal stress (σ H ), minimum horizontal stress (σ h ), Poisson's ratio (v), tolerable breakout width (ω), pore pressure (p p ), strength parameters (c, ϕ) and Biot's coefficient (α) are usually uncertain. The basic random variables of loads and resistances of wellbore collapse can be expressed as:…”

Section: Equivalent Mud Weight Of Collapse Pressure (Emwcp)mentioning

confidence: 99%

“…However, due to the uncertainty of formation lithology, the uncertainty of formation pressure, the uncertainty of mechanical properties of rocks, and the unstable wellbore pressure, the input parameters of wellbore stability analysis never can be known precisely. In other words, the input parameters are often uncertain, which might cause an incorrect result [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. In order to quantify the influence of uncertain parameters on wellbore stability and SMWW, it's necessary to utilize reliability assessment method.…”

Section: Introductionmentioning

confidence: 99%

“…Udegbunam et al [23] investigated typical fracture and collapse models with respect to inaccuracies in the input data with a stochastic method. Kinik et al [24,25] presented a mathematical model to estimate the true fracture pressure from the leak-off-test data, and the QRA was also involved to represent the probability-density distribution of fracture pressure. Gholami et al [26] applied the QRA to consider the uncertainty of input parameters in determining of the mud weight window for different failure criteria, such as the Mohr-Coulomb (M-C), Hoek-Brown (H-B) and Mogi-Coulomb (MG-C) criterion.…”

Section: Introductionmentioning

confidence: 99%

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Uncertainty Evaluation of Safe Mud Weight Window Utilizing the Reliability Assessment Method

Tang

Chen

et al. 2019

Energies

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Due to the uncertainty of formation properties and improper wellbore stability analysis methods, the input parameters are often uncertain and the required mud weight to prevent wellbore collapse is too large, which might cause an incorrect result. However, the uncertainty evaluation of input parameters and their influence on safe mud weight window (SMWW) is seldom investigated. Therefore, the present paper aims to propose an uncertain evaluation method to evaluate the uncertainty of SMWW. The reliability assessment theory was introduced, and the uncertain SMWW model was proposed by involving the tolerable breakout, the Mogi-Coulomb (MG-C) criterion and the reliability assessment theory. The influence of uncertain parameters on wellbore collapse, wellbore fracture and SMWW were systematically simulated and investigated by utilizing Monte Carlo simulation. Finally, the field observation of well SC-101X was reported and discussed. The results indicated that the MG-C criterion and tolerable breakout is recommended for wellbore stability analysis. The higher the coefficient of variance is, the higher the level of uncertainty is, the larger the impact on SMWW will be, and the higher the risk of well kick, wellbore collapse and fracture will be. The uncertainty of basic parameters has a very significant impact on SMWW, and it cannot be ignored. For well SC-101X, the SMWW predicted by analytical solution is 0.9921–1.6020 g/cm3, compared to the SMWW estimated by the reliability assessment method, the reliability assessment method tends to give a very narrow SMWW of 1.0756–1.0935 g/cm3 and its probability is only 80%, and the field observation for well kick and wellbore fracture verified the analysis results. For narrow SMWW formation drilling, some kinds of advanced technology, such as the underbalanced drilling (UBD), managed pressure drilling (MPD), micro-flow drilling (MFD) and wider the SMWW, can be utilized to maintain drilling safety.

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Section: Equivalent Mud Weight Of Collapse Pressure (Emwcp)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Uncertainty Evaluation of Safe Mud Weight Window Utilizing the Reliability Assessment Method

Tang

Chen

et al. 2019

Energies

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“…Plazas et al (2015) [8] applied reliability methods to assess the risk of wellbore instability in the Colombian Cretaceous formation. Kinik (2016) [9] employed the Quantitative Risk Assessment (QRA) method to study the probability density distribution of reliability under the influence of input parameter uncertainty for fracture pressure in vertical wells. They also considered the impact of temperature-induced effective stress.…”

Section: Introductionmentioning

confidence: 99%

Risk Analysis of Wellbore Instability of “Felt Layer” in Qiudong Sag Based on Monte Carlo Method

Jia,

Zhu,

Song

et al. 2024

Processes

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Both domestic and international scholars have conducted in-depth research on wellbore stability issues. They have established various empirical models, analytical models, and numerical simulation methods. However, there is relatively little research on the impact of the uncertainty of input parameters on wellbore stability, and the understanding of this aspect remains unclear. To address this, this paper introduces a probability distribution method. It is based on a wellbore stability mechanical analytical model and, using reliability theory, establishes a method for evaluating wellbore instability risks. By employing the Monte Carlo random simulation method, this study investigates the sensitivity of input parameters to wellbore stability, clarifying that ground stress is the main controlling factor affecting wellbore stability. Combining the analysis of the “felt layer” ground stress profile, this study utilizes two-dimensional simulation experiments to validate the accurate determination of ground stress magnitude in wellbore stability analysis. It also examines the impact of reducing its uncertainty. The results show that this approach significantly reduces the risk of wellbore instability, addressing the challenging issue of identifying wellbore instability in the Qiu Dong Depression’s “felt layer” within the TH Basin.

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A Switching MPD Controller for Mitigating Riser Gas Unloading Events in Offshore Drilling

Fallah

Ambrus

et al. 2020

SPE Drilling &Amp; Completion

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Summary Riser gas unloading events in subsea well construction are hazardous and difficult to control. When a gas influx enters the wellbore and dissolves in nonaqueous fluids (NAFs), it may go unnoticed because the pit gain on the surface may be minimal and remain below the detection threshold when using conventional well control indicators. Once the dissolved gas is circulated up and comes out of the solution at pressure and temperature conditions below the bubblepoint, it can quickly displace a large volume of mud in the riser or the chokeline. When this breaking out of gas occurs at a shallow depth, it leaves little time for the rig crew to react. In this paper, we present a novel managed pressure drilling (MPD) approach for riser gas unloading control that makes use of a pressurized riser drilling (PRD) controller. The PRD method employs the constant bottomhole pressure (CBHP) controller for normal operations (e.g., drilling and circulation of kick), whereas it offers a more comprehensive way to manage and control a riser gas unloading behavior. The PRD choke controller dynamically applies a backpressure on the dissolved gas–NAF mixture in the riser to delay, minimize, or even prevent the gas breaking out at locations closer to the surface. The control algorithm considers the pressure limits of the riser and of the openhole formations and can adjust for kick uncertainties (e.g., whether the kick is a gas, liquid, or both, its volume and distribution). The proposed PRD controller consists of three operation modes: pressure control mode, flow control mode, and solubility control mode, with each mode applicable to its corresponding operating condition. The controller can automatically switch among different modes on the basis of the observed kick behavior, thereby gaining the ability to compensate for the limitations of the individual control modes and, more importantly, to deal with kicks agnostically, i.e., independent of their nature. The proposed controller is evaluated by simulating different riser gas unloading scenarios. Here, two distinct cases are given special consideration: (1) the case in which the subsea blowout preventers (BOPs) remain open after the kick passes them and the controller regulates the pressure using the maximum allowable surface pressure (MASP) or downhole fracture gradient as an upper limit and (2) the case in which the subsea BOPs are closed after the kick passes them and the controller regulates the pressure within the riser pressure limits when the kick is circulated to the surface using the riser booster pump. Simulation results show that the proposed controller can quickly and robustly control the riser gas unloading situations with complicated transient conditions, without fracturing downhole formations or jeopardizing the pressure integrity of the riser. The developed PRD controller aims to help mitigate some of the concerns about riser gas unloading when the dissolved gas is allowed to pass the subsea BOPs and enter the riser and to facilitate the implementation of more automated subsea well control using MPD technology in the foreseeable future.

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Probabilistic Assessment of the Temperature-Induced Effective Fracture Pressures

Cited by 3 publications

References 58 publications

Uncertainty Evaluation of Safe Mud Weight Window Utilizing the Reliability Assessment Method

Uncertainty Evaluation of Safe Mud Weight Window Utilizing the Reliability Assessment Method

Risk Analysis of Wellbore Instability of “Felt Layer” in Qiudong Sag Based on Monte Carlo Method

A Switching MPD Controller for Mitigating Riser Gas Unloading Events in Offshore Drilling

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