Petroleum and natural gas industries. Drilling fluids. Processing equipment evaluation

Abstract In this experimental work, the absorption and desorption of CO2 (Carbon Dioxide) in oil using a laboratory scale low-pressure experimental apparatus was conducted to study the dissolution behavior of gas in the oil. Estimating the concentration and rate of CO2 transfer from/to a non-aqueous column of static fluid is very important to understand the dissolution of natural gas in an oil-based mud within a well. Studying how natural gas dissolves in an oil-based drilling fluid is of great significance due to risks that a gas kick in an oil-based mud poses to equipment and workers’ health and safety once it is in the riser. By understanding the variables associated with this phenomena, better field practices can be developed and implemented to predict the dynamics of an influx and determine the best course of action when handling the influx. A laboratory scale experimental apparatus was designed and built to inject CO2 at the bottom of a seven-foot static column of VO. The apparatus has five test chambers that can be closed individually to isolate and measure the concentration of dissolved CO2 in oil in each of the sections. As a part of the experiment, the the backpressure applied to the column of oil was varied to observe how pressure affects the mass transfer due to absorption and desorption within the oil column. The amount of gas injected was 1.0 liter per minute of CO2 with a back pressure of the apparatus ranging from 40 to 80 psi. The results of this study will influence further experiments and testing using larger scale equipment involving the dissolution of natural gas within various oil-based drilling fluids at higher pressures. This study also allows for the development of an initial time-dependent mass transfer model which will also be used for predicting dissolution dynamics of Methane in diesel for future large-scale testing.

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High-pressure experimental vapour-liquid-liquid equilibrium measurements and modelling for natural gas processing: Equipment validation, and the system CH4+nC6H14+H2O

Fluid Phase Equilibria ◽

10.1016/j.fluid.2019.112276 ◽

2019 ◽

Vol 501 ◽

pp. 112276

Author(s):

Francois Kruger ◽

Athanasios A. Varsos ◽

Georgios M. Kontogeorgis ◽

Nicolas von Solms

Keyword(s):

High Pressure ◽

Natural Gas ◽

Liquid Equilibrium ◽

Processing Equipment ◽

Gas Processing ◽

Natural Gas Processing

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Buoyancy Induced Convection of Riser Gas in Deepwater Drilling Operations

Volume 8: Polar and Arctic Sciences and Technology; Petroleum Technology ◽

10.1115/omae2019-96649 ◽

2019 ◽

Author(s):

Syed Y. Nahri ◽

Yuanhang Chen ◽

Wesley Williams ◽

Otto Santos ◽

Ting Sun

Keyword(s):

Mass Transfer ◽

Natural Gas ◽

Drilling Fluid ◽

Gas Absorption ◽

Petroleum Engineering ◽

Drilling Fluids ◽

Engineering Research ◽

Deepwater Drilling ◽

Area Of Interest ◽

Drilling Operations

Abstract Riser gas migration has been an area of interest since the last three decades due to its importance in gas handling in deepwater drilling operations. A previously conducted full-scale test at LSU Petroleum Engineering Research & Technology Transfer (PERTT) well facility indicates, as contrary to traditional belief, significant migration of dissolved gas taking place even when circulation had ceased. In order to understand whether a reduction in density of the underlying contaminated mud resulting from gas absorption is the contributing factor to the above-mentioned phenomenon, a computational fluid dynamics (CFD) analysis was conducted to study the transport of the gas influx while in solution due to buoyancy induced convective mass transfer and simultaneous diffusion. Simulations performed in this study include the hydrodynamics of the upward moving gas cut mud and simultaneous mass transfer of natural gas into the under-saturated drilling fluid. The parameters studied here are the distance traveled of the gas cut mud and saturation levels in the drilling fluid along the length of the riser. The dense phase behavior was shown to have considerable effects on gas loading capacities which in turn affected the density of the gas cut mud, and at pressures upwards of 5,000 psi, the solubility of a natural gas influx can be seen to be infinite in certain synthetic and oil-based drilling fluids. The rate and extent of mass transfer are dependent on drilling fluid density gradients, which in turn are based on gas influx saturation level. Results obtained from this study can help better comprehend migration phenomena of a dissolved influx in oil-based muds in a riser with the BOP shut in and when circulation has ceased.

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

Volume 11: Petroleum Technology ◽

10.1115/omae2020-18115 ◽

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).

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