Numerical Simulation of Non-Equilibrium Phase Behavior of Hydrocarbons for Modeling Oil and Gas Fields with Gas Injection

Numerical models widely used for hydrocarbon phase behavior and compositional flow simulations are based on assumption of thermodynamic equilibrium. However, it is not uncommon for oil and gas-condensate reservoirs to exhibit essentially non-equilibrium phase behavior, e.g., in the processes of secondary recovery after pressure depletion below saturation pressure, or during gas injection, or for condensate evaporation at low pressures. In many cases the ability to match field data with equilibrium model depends on simulation scale. The only method to account for non-equilibrium phase behavior adopted by the majority of flow simulators is the option of limited rate of gas dissolution (condensate evaporation) in black oil models. For compositional simulations no practical yet thermodynamically consistent method has been presented so far except for some upscaling techniques in gas injection problems. Previously reported academic non-equilibrium formulations have a common drawback of doubling the number of flow equations and unknowns compared to the equilibrium formulation. In the paper a unified thermodynamically-consistent formulation for compositional flow simulations with non-equilibrium phase behavior model is presented. Same formulation and a special scale-up technique can be used for upscaling of an equilibrium or non-equilibrium model to a coarse-scale non-equilibrium model. A number of test cases for real oil and gas-condensate mixtures are given. Model implementation specifics in a flow simulator are discussed and illustrated with test simulations. A non-equilibrium constant volume depletion algorithm is presented to simulate condensate recovery at low pressures in gas-condensate reservoirs. Results of satisfactory model matching to field data are reported and discussed.

Download Full-text

Assessment of Non-Equilibrium Phase Behavior Model Parameters for Oil and Gas-Condensate Systems by Laboratory and Field Studies (Russian)

10.2118/201956-ru ◽

2020 ◽

Author(s):

Ilya Mikhailovich Indrupskiy ◽

Mikhail Yurievich Danko ◽

Timur Nikolaevich Tsagan-Mandzhiev ◽

Ayguzel Ilshatovna Aglyamova

Keyword(s):

Phase Behavior ◽

Oil And Gas ◽

Equilibrium Phase ◽

Field Studies ◽

Gas Condensate ◽

Model Parameters ◽

Behavior Model ◽

Non Equilibrium

Download Full-text

Prediction of thermodynamic properties and phase behavior of reservoir fluids for the design of oil and gas fields

Proceedings of Gubkin Russian State University of Oil and Gas ◽

10.33285/2073-9028-2020-1(298)-47-61 ◽

2020 ◽

pp. 47-61

Author(s):

B.A. Grigoriev ◽

◽

I.S. Alexandrov ◽

A.A. Gerasimov ◽

E.B. Grigoriev ◽

...

Keyword(s):

Thermodynamic Properties ◽

Phase Behavior ◽

Oil And Gas ◽

Oil And Gas Fields ◽

Gas Fields

Download Full-text

Severe Slugging Control Methods Used in Offshore Multiphase Riser

Volume 6: Polar and Arctic Sciences and Technology; Offshore Geotechnics; Petroleum Technology Symposium ◽

10.1115/omae2013-11474 ◽

2013 ◽

Author(s):

Bing Cheng ◽

Qingping Li ◽

Haiyuan Yao

Keyword(s):

Oil And Gas ◽

Gas Injection ◽

Injection System ◽

Control Methods ◽

Future Design ◽

Oil And Gas Fields ◽

Normal Production ◽

Gas Fields ◽

Mitigation Methods ◽

Gas Lift

Severe slugging control in offshore riser is an important aspect of flow assurance, if not well controlled, normal production could be interrupted and jeopardized. In this paper, firstly mitigation methods for severe slugging used in different oilfields are investigated, and their pros&cons, on-site applications and application scope are summarized. Then three severe slugging control methods adopted by CNOOC are introduced, respectively GLCC separation, auto choking, as well as gas lift. GLCC combined with the original slug catcher has solved the slug problem of the QK17-2 Oilfield, saving a lot of space and money. A set of online monitoring and auto-choking system was successfully installed and applied in WC Oilfield, contributing a lot to the production stability and production rate. The delicately designed gas lift annulus and gas injection system are expected to mitigate severe slugging and boost production of a west Africa deepwater oilfield co-explored by CNOOC. The introduction of these on-site cases will be of some value to for future design and analysis of severe slugging control for oil and gas fields.

Download Full-text

Application of Unbalanced Load Sharing to Compensate Low Compressor Train Capacity

10.29118/ipa21-f-166 ◽

2021 ◽

Author(s):

Y. H. Putra

Keyword(s):

Load Distribution ◽

Capital Investment ◽

Oil And Gas ◽

Gas Injection ◽

Load Sharing ◽

Central Processing ◽

Oil And Gas Fields ◽

Processing Facility ◽

Unbalanced Load ◽

Gas Fields

Oil and gas fields often operate two or more compressor trains in parallel instead of one big compressor train to optimize reliability and capital investment. These compressor trains are usually designed to be loaded equally in order to avoid excessive design margin, to operate at highest efficiency point, and to prevent any compressor from operating too close to its surge region (McMillan, 1983). However, this configuration means the lowest train’s capacity dictates overall system’s capacity. This paper shares Banyu Urip Central Processing Facility (BU CPF)’s successful strategy to compensate capacity decrease in one of its gas injection train using unbalanced load distribution. Upon implementation of the strategy, BU CPF managed to maintain operations at 100% gas injection capacity even though the capacity of one of the train was limited to 70%, therefore eliminating unplanned downtime or production curtailment.

Download Full-text