scholarly journals Multiphase transient flow model in wellbore annuli during gas kick in deepwater drilling based on oil-based mud

2017 ◽  
Vol 51 ◽  
pp. 159-198 ◽  
Author(s):  
Bangtang Yin ◽  
Gang Liu ◽  
Xiangfang Li
Keyword(s):  
Flow Model ◽  
Transient Flow ◽  
Deepwater Drilling ◽  
Gas Kick

Use of a Transient Model for Studying Kick Migration Velocities and Build-Up Pressures in a Closed Well

2021 ◽  
Author(s):  
Thea Hang Ngoc Tat ◽  
Dalila Gomes ◽  
Kjell Kåre Fjelde
Keyword(s):  
Flow Model ◽  
Transient Flow ◽  
Flow Patterns ◽  
Drilling Fluids ◽  
Transient Model ◽  
Drift Flux Model ◽  
Drift Flux ◽  
Gas Kick ◽  
Flux Model ◽  
Migration Velocities

Abstract The objective of the paper is to show that using pressure build-up curves for estimating kick migration velocities can be unreliable. This will be demonstrated by using a transient flow model where different flow patterns including suspended gas are considered. Suspended gas will occur in Non-Newtonian drilling fluids. This can also be the reason why there is reported large discrepancies in literature about what the gas kick migration velocities can be. A transient flow model based on the drift flux model supplemented with a gas slip relation will be used. The model will be solved by an explicit numerical scheme where numerical diffusion has been reduced. Different flow patterns are included i.e. suspended gas, bubble flow, slug flow and transition to one-phase gas. Kick migration in a closed well will be studied to study how pressure build-ups evolve. A sensitivity analysis will be performed varying kick sizes, suspension limits and changing the transition intervals between the flow patterns. It is seen in literature that the slope of the pressure build-up for a migrating kick in a closed well has been used for estimating what the kick velocity is. It has been reported earlier that this can be an unreliable approach. In the simulation study, it is clearly demonstrated that the suspension effect will have a significant impact of reducing the slopes of the pressure build-ups from the start of the kick onset. In some severe cases, the pressure builds up but then it reaches a stable pressure quite early. In these cases, the kick has stopped migrating in the well. However, in the cases where the kicks are still migrating, it seems that the bulk of the kick moves at the same velocity even though the degree of suspension is varied and gives different slopes for the pressure build-up. Hence, it seems impossible to deduce a unique gas velocity from different pressure build-up slopes. However, abrupt changes in the slope of the pressure build-up indicate flow pattern transitions.

Modelling present and future Po river interactions with alluvial aquifers (Low Po River Plain, Italy)

2014 ◽  
Vol 5 (3) ◽  
pp. 457-471 ◽  
Author(s):  
M. Mastrocicco ◽  
N. Colombani ◽  
A. Gargini
Keyword(s):  
Groundwater Flow ◽  
Large Scale ◽  
Flow Model ◽  
Transient Flow ◽  
Scale Model ◽  
Groundwater Flow Model ◽  
Po River ◽  
Local Conditions ◽  
Aquifer System ◽  
Hydrological Conditions

A modelling study on a multi-layered confined/unconfined alluvial aquifer system was performed to quantify surface water/groundwater interactions. The calibrated groundwater flow model was used to forecast climate change impacts by implementing the results of a downscaled A1B model ensemble for the Po river valley. The modelled area is located in the north-western portion of the Ferrara Province (Northern Italy), along the eastern bank of the Po river. The modelling procedure started with a large scale steady state model followed by a transient flow model for the central portion of the domain, where a telescopic mesh refinement was applied. The calibration performance of both models was satisfactory, in both drought and flooding conditions. Subsequently, forecasted rainfall, evapotranspiration and Po river stage at 2050, were implemented in the calibrated large scale groundwater flow model and their uncertainties discussed. Three scenarios were run on the large scale model: the first simulating mean hydrological conditions and the other two simulating one standard deviation above and below the mean hydrological conditions. The forecasted variations in groundwater/Po river fluxes are relevant, with a general increase of groundwater levels due to local conditions, although there are large uncertainties in the predicted variables.

A novel dilution control strategy for gas kick handling and riser gas unloading mitigation in deepwater drilling

2021 ◽  
Vol 196 ◽  
pp. 107973
Author(s):  
Qifan Gu ◽  
Amirhossein Fallah ◽  
Tianheng Feng ◽  
Soovadeep Bakshi ◽  
Dongmei Chen ◽  
...  
Keyword(s):  
Control Strategy ◽  
Deepwater Drilling ◽  
Gas Kick

Probabilistic Flow Modelling Approach for Kick Tolerance Calculations

2017 ◽  
Author(s):  
Dalila Gomes ◽  
Knut Steinar Bjørkevoll ◽  
Johnny Frøyen ◽  
Kjell Kåre Fjelde ◽  
Dan Sui ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Pore Pressure ◽  
Flow Model ◽  
Transient Flow ◽  
Probabilistic Approach ◽  
Numerical Approach ◽  
Free Form ◽  
Maximum Pressure ◽  
Fracture Pressure ◽  
Calculation Process

During drilling, there must be an evaluation of the maximum pressure that the formation can handle during a well kill scenario. This will depend on various parameters like fracture pressure, pore pressure, kick volume and several other factors. The depth of the next planned hole section will depend on if a kick of a certain size can be handled safely. This evaluation is often referred to as performing kick tolerances. When starting to drill a section, one will take a leak off test to get an indication of the fracture pressure at the last set casing shoe and this will be important information for the kick tolerance results. For HPHT wells the margin between pore and fracture pressures will be small, and one often has to resort to using transient flow models to perform the kick tolerances. However, there are many uncertain parameters that are affecting the results. Some examples here are pore pressure, type of kick and kick distribution. There is a need for trying to incorporate the uncertainty in the calculation process to give a better overview of possible outcomes. This approach has become more and more popular, and one example here is reliability based casing design. This paper will first describe the kick tolerance concept and its role in well design planning and operational follow up. An overview of all parameters that can affect the results will be given. In water based mud, the gas kick will be in free form yielding higher maximum casing shoe pressures compared to the situation when oil based mud is used where the kick can be fully dissolved. Then it will be shown how both an analytical and a transient flow model can be used in combination with the use of Monte Carlo simulations to generate a probabilistic kick tolerance calculation showing possible outcomes for maximum casing shoe pressure for different kick volumes. Here uncertain input parameters that can affect the calculation result will be drawn from statistical distributions and propagated through the flow model to estimate the casing shoe pressure. Multiple runs will be needed in the Monte Carlo simulation process to generate a distribution of the maximum casing shoe pressure. This will demand a rapid and robust flow model. The resulting maximum casing shoe pressure distribution will then be compared against the uncertainty in the fracture pressure at the last set casing shoe to yield a probability for inducing losses. The numerical approach for predicting well pressures and a schematic of the total calculation process will be given. Emphasis will also be put on discussing how this should be presented to the engineer with respect to visualization and communication. It will also be shown that one of the strengths of the probabilistic approach is that it is very useful for performing sensitivity analysis such that the most dominating factors affecting the calculation results can be identified. In that way, it can help in interpreting and improving the reliability of the kick tolerance simulation results.

A Simple Transient Flow Model for MPD and UBD Applications

2014 ◽  
Author(s):  
John Emeka Udegbunam ◽  
Kjell Kayre Fjelde ◽  
Steinar Evje ◽  
Gerhard Nygaard
Keyword(s):  
Flow Model ◽  
Transient Flow

Kalman Filter and Model-Free Adaptive Control Theory Applied to the Unsteady Flow State Estimation of Product Pipelines

2020 ◽  
Author(s):  
Lei He ◽  
Kai Wen ◽  
Jing Gong
Keyword(s):  
Unsteady Flow ◽  
Linear Model ◽  
Flow Model ◽  
Transient Flow ◽  
Linear Method ◽  
Model Parameters ◽  
Flow State ◽  
Transient Pressure ◽  
Linear Flow ◽  
Model Based

Abstract The accurate online estimation of unsteady flow state provides important operation information for product pipelines real-time scheduling. In practice, affected by the parameter drift and observation noises, traditional estimation methods based on the first principle can hardly provide accurate results within acceptable time. The nonlinear and fast transient characteristics of pipeline flow make it difficult to realize on-line adaptive modification of model parameters. In order to meet the requirements of computational efficiency and accuracy simultaneously, this paper proposes a methodology with two-level adaptive adjustment to realize the digital twin of pipeline nonlinear transient flow process by using simplified linear flow model. In terms of improving computing efficiency, the linear flow model based on frequency response and difference transforming is established to process the on-line state estimation of transient flow. To reduce the deviation between the actual observed value and the linear model estimation, we first introduce mode-free adaptive control method as linear compensation of the reduced order unsteady flow model. The compact form dynamic linearization method has been adopted to design the virtual input of the linear flow model. To further improve the adaptability of the linear model, the model parameters are online adjusted by using the recursive least squares with forgetting factor method. The uncertainty of the model and the interference of observation noise is eliminated by adopting Kalman filter to the state space model based on modified linear model. The effectiveness of the proposed methodology is evaluated by applying to the digital twin process of a product pipeline transient pressure in a multistation pipeline. The results show that the proposed method can make transient pressure estimation of second-order linear model agree well with the value of nonlinear flow model even under unforeseen conditions and noise interference. The performance of the proposed method is better than model-based linear method, data-driven linear method and nonlinear method.

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