Predicting Gas Kick Behavior in Oil-Based Drilling Fluids Using a PC-Based Dynamic Wellbore Model

1990 ◽  
Author(s):  
D.C. Van Slyke ◽  
E.T.S. Huang
Keyword(s):  
Drilling Fluids ◽  
Gas Kick

A Simplified Two-Phase Flow Model for Riser Gas Management With Non-Aqueous Drilling Fluids

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Nnamdi Nwaka ◽  
Chen Wei ◽  
Yuanhang Chen
Keyword(s):  
Drilling Fluids ◽  
Gas Migration ◽  
Dissolved Gas ◽  
Two Phase ◽  
Simplified Approach ◽  
Drift Flux Model ◽  
Drift Flux ◽  
Gas Kick ◽  
Flux Model ◽  
Using Data

Abstract Gas-in-riser events can lead to rapid unloading if not timely controlled in a proper manner. When gas influx enters a wellbore with non-aqueous muds (NAMs), the ability of gas being dissolved in NAMs increases the difficulty in gas kick detection and significantly alters gas migration and unloading behavior from the predictions based on water-based muds (WBMs) assumptions. In this study, a new mathematical model for riser gas management in NAMs is developed. In this model, the desorption of dissolved gas influx from NAMs is accounted for as an instantaneous process using a solubility-based mass transfer submodel. The effects of surface backpressures and circulation rates on the unloading behavior in both WBMs and NAMs were studied. This model was validated using data obtained from a drift-flux model (DFM) based simulator. Results show that with the same amount of free gas in the risers at the mudline level, the severity of unloading is significantly more severe in the cases of NAMs. Applied backpressure can effectively control the desorption of the gas influx from the mud, and the unloading occurs later and at shallower depth with higher backpressure. The behavior of unloading tends to be independent on the time when backpressures are applied but highly dependent on the magnitude of the backpressure and the circulation rates. The new two-phase model can accurately simulate riser gas kick events utilizing a simplified approach with improved numerical stability, making it more applicable for real-time riser gas management.

Estimating Swelling in Oil-Based Mud due to Gas Kick Dissolution

2020 ◽  
Author(s):  
Kaushik Manikonda ◽  
Abu Rashid Hasan ◽  
Omer Kaldirim ◽  
Nazmul Rahmani ◽  
Mohammad Azizur Rahman
Keyword(s):  
Liquid Phase ◽  
Natural Gas ◽  
Drilling Fluid ◽  
Binary Interaction ◽  
Drilling Fluids ◽  
Gas Solubility ◽  
Interaction Coefficients ◽  
Volume Factor ◽  
Cubic Form ◽  
Gas Kick

Abstract Gas kick is an ever-present hazard whose importance is magnified for offshore drilling situations. Modeling gas kick is a complex problem that requires an understanding of the relevant fluid dynamics as well as the solubility of natural gas in oil-based muds (OBM). Drilling fluid swelling due to natural gas solubility in OBM significantly affects the extent of pit gain — one of the primary indicators of a kick in progress. This paper specifically addresses the issue of drilling fluid swelling from gas dissolution in OBM. Drilling fluid swelling due to gas dissolution is generally expressed the same way as oil swelling due to dissolved gas, by the volume factor, Bo. Many correlations for estimating Bo as a function of temperatures and pressures are available. We have developed a rigorous thermodynamic approach for estimating Bo. Our approach uses the Peng-Robison (1976) equation of state (EOS), van der Waals mixing rules, and binary interaction coefficients appropriate for drilling fluids to account for gas solubility. Solving the cubic form of the Peng-Robinson EOS yields a z-factor for the liquid phase of the mixture. The model uses this z-factor to estimate the liquid-phase volume of dissolved methane and, consequently, Bo. This paper validates the results of estimated Bo from this method with volume factor calculations obtained from Aspen HYSYS. Finally, this paper also presents a section where the methane mole fraction data at different P&T conditions, obtained from HYSYS simulations, is used to validate the solubility model previously developed by Manikonda et al. (2019).

Gas kick detection and pressure transmission in thixotropic, compressible drilling fluids

2019 ◽  
Vol 180 ◽  
pp. 138-149 ◽  
Author(s):  
Jonathan F. Galdino ◽  
Gabriel M. Oliveira ◽  
Admilson T. Franco ◽  
Cezar O.R. Negrão
Keyword(s):  
Drilling Fluids ◽  
Gas Kick ◽  
Pressure Transmission

Numerical Modelling and Sensitivity Analysis of Gas Kick Migration and Unloading of Riser

2019 ◽  
Author(s):  
Dalila Gomes ◽  
Knut S. Bjørkevoll ◽  
Kjell K. Fjelde ◽  
Johnny Frøyen
Keyword(s):  
Sensitivity Analysis ◽  
Transient Flow ◽  
Numerical Algorithms ◽  
Drilling Fluids ◽  
Two Phase ◽  
Worst Case ◽  
Numerical Diffusion ◽  
Flow Models ◽  
Gas Kick ◽  
Water Based

Abstract In deepwater wells there is a risk of gas entering the riser. This can be caused by gas being trapped by the BOP after a well kill operation, or it can be that the BOP was not closed quickly enough upon kick detection. With oil-based mud (OBM), gas is dissolved, and larger kicks may go undetected and circulated up in the riser by accident. If a gas kick comes into the riser, a rapid unloading event can occur. This can in worst case lead to a blowout scenario. In addition, the riser may be subject to a collapse load due to reduced liquid level inside. The unloading behavior will be different when comparing kicks in oil-based and water-based mud (WBM). For water-based muds, field experience and experiments have shown that gas can be trapped by the mud. This effect is the same that causes mud to capture cutting particles, and it is related to the non-Newtonian and time-dependent rheology behavior of the mud. The suspended gas can only be removed from the riser by circulation. The kick must therefore be of a certain volume to be able to unload the well. Modelling of the mentioned complex phenomena, with the violent transient phase seen when a large volume of gas expands as it moves towards the liquid surface in the riser, is still a challenge for numerical algorithms to do accurately and reliably. Robust handling of numerical diffusion in two-phase flow is one of the key topics, as are slippage and extension of gas in the liquid. The paper describes how an explicit numerical scheme (AUSMV) is used as a numerical solver with the application of the slope-limiter technique to handle numerical diffusion. This has not yet been done for unloading of gas in riser. A simulation case will be constructed considering gas migration and expansion in a long riser. A sensitivity analysis will be performed where both the kick volumes and the threshold for gas suspension will be varied to study when kicks will start to unload the well vs. situations where they will become fully suspended. The phenomena mentioned will be studied for water-base drilling fluids. The paper will review previous work on the subject and highlight how transient flow models can be useful for gaining more insight into how the gas behaves in risers and what can be done to mitigate the consequences.

Understanding Gas Kick Behavior in Water and Oil-Based Drilling Fluids

2019 ◽  
Author(s):  
Kaushik Manikonda ◽  
Abu Rashid Hasan ◽  
Omer Kaldirim ◽  
Jerome J. Schubert ◽  
Mohammad Azizur Rahman
Keyword(s):  
Drilling Fluids ◽  
Gas Kick

Gas-Kick Simulation in Oil-Based Drilling Fluids with Nonequilibrium Gas-Dissolution and -Evolution Effects

SPE Journal ◽  
2021 ◽  
pp. 1-21
Author(s):  
Zhengming Xu ◽  
Xuejiao Chen ◽  
Xianzhi Song ◽  
Zhaopeng Zhu ◽  
Wenping Zhang
Keyword(s):  
Drilling Fluid ◽  
Drilling Fluids ◽  
Gas Evolution ◽  
Dissolved Gas ◽  
Efficient Treatment ◽  
Nonequilibrium Gas ◽  
Gas Kick ◽  
Wellbore Pressure ◽  
Outflow Rate ◽  
State Models

Summary The nonequilibrium dissolution and evolution characteristics of gas in oil-based drilling fluids (OBDFs) greatly affect the ratio of free gas to dissolved gas in the wellbore, thus influencing the prediction accuracy of the wellbore-pressure and surface responses. Previous equilibrium-state models can result in the incorrect estimation of the multiphase-flow parameters during a gas kick in OBDFs. Therefore, a nonequilibrium gas/liquid two-phase-flow model is developed for simulations of gas kicks in OBDFs. Nonequilibrium gas-kick behaviors in OBDFs are investigated using the proposed model, and it is concluded that there is a unique gas-dissolving stage in comparison to the equilibrium gas-kick conditions. In this stage, the pit gain decreases to a large extent, and this phenomenon can be misinterpreted by the drilling crew as a loss of circulation or a decrease in the gas-kick intensity. The drilling-fluid-outflow rate is not a reliable gas-kick indicator because of the lower increment in the drilling-fluid-outflow rate under both nonequilibrium and equilibrium gas-dissolution conditions. Neglecting the gas-evolution rate in OBDFs could lead to overestimations of the maximum pit gain and the drilling-fluid-outflow rate. More gas moves from the wellbore in the form of dissolved gas under noninstantaneous gas-evolution conditions. The results of this study provide a theoretical basis for the safe and efficient treatment of gas kicks in OBDFs.

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.

Sign in / Sign up

Export Citation Format

Share Document