Properties of natural gas and condensates i png 520. These conditions are favor able for the gascondensate mixture to be completely in the gaseous state in the reservoir. We start with a singlephase gas reservoir fluid, of a known composition, at an initial reservoir pressure and temperature. The development of gas condensate reservoirs by gas injection is treated in chapter 12. Ron terry discusses gas condensate reservoirs, calculating hydrocarbon in place using two methods. Gas condensates are hydrocarbons in which conditions of temperature and pressure have resulted in the condensation of heavier hydrocarbons from the reservoir gas. Spe, iniercomp resource development ana engineering, inc. Composition of gas condensate knowledge of the gasliquid ratlo and the gravity of the lcluid s not sufficient to describe the composi tion of gas condensate for all. Estimating reservoir composition for gas condensates and. Preliminary reserve estimates are that the field contains approximately 200 million barrels of condensate and over 2 tcf of natural.
A gas condensate with low condensate formation in the reservoir when the bottomhole pressure is reduced below the dewpoint pressure. Its presence as a liquid phase depends on temperature and pressure conditions in the reservoir allowing condensation of liquid from vapor. Simulation of gas condensate reservoir performance keith h. Determination of reservoir fluid composition from a nonrepresentative fluid sample 3 adjusted parameters from the first step, thermodynamic equilibrium, at a saturation pressure equal to the static pressure, was obtained. Yang 2 from an engineering point of view, the two extra issues which must be addressed in a gas condensate reservoir are. Natural gas condensate aka gas condensate, condensate, natural gas liquids is a lowdensity, highapi gravity liquid hydrocarbon phase that generally occurs in association with natural gas. Studies of retrogradecondensate gas reservoirs must consider changes in. In case of isothermal reduction of the formation pressure, part of them condenses in the form of gas condensate. A full spectrum of gas reservoir engineering techniques is addressed and their application to a large variety of gas resource management options is discussed. Appendix a lists the commonly used units in gas reservoir engineering, along with their conversion factors. Nov 16, 2015 fluid flow in gas condensate reservoirs usually exhibit complex flow behavior when the flowing bottomhole pressure drops below the dewpoint. Simulation study of enhanced condensate recovery in a gas condensate reservoir iranian journal of chemical engineering, vol.
The gas condensate separated from natural gas at reduced pressure andor temperature by reverse condensation is a colorless or slightly colored liquid of density 700800 kgm 3, which begins to boil at 3070c. According to the previous studies, the addition of some nitrogen causes a considerable increase in mixture dew. Sep 27, 20 this video is considered as an educational video used for nonprofitable purpose for all petroleum and nonpetroleum students in bue the british university in egypt and any other user for. Fluid composition is determined by capturing a representative sample of reservoir. The production of condensate reservoirs can be complicated. Gas injection techniques for condensate recovery and. This casts new insight into the conventional explanation that the productivity loss in gas condensate reservoirs, when the pressure near the wellbore reaches the dew point, is only due to relative permeability effects.
How the condensate yield will vary during the life of a reservoir, and. A good understanding of how the gas condensate reservoirs vary in. The field was discovered in 2005 by delta petroleum corporation, with the drilling of the state 3611 well approximately 2 miles south of the town of green river, utah. This course will help participants understand the engineering drivers on gas reservoir management and how a gas reservoirs value can be maximized through sound engineering practices. The gascondensate content in gases of various deposits ranges from 12 to 700 cm 3 per 1 m 3 of gas. Pseudocritical conditions of undersaturated reservoir liquids. The only liquid associated with the gas from a dry gas reservoir is water. Once equilibrium was reached, the remaining free gas was liberated 5. Iran gerami, shahab ior research institute, national iranian oil company nioc, i. The difficulty lies in the variation of the composition of the insitu fluid due. Compositional modeling of gascondensate reservoirsthe. Jasmine, a gascondensate reservoir, is located 240km south east of the coast of aberdeen and is expected to start production at the end of 2012. This case study investigated the effects of formation reservoir properties, aquifer influx, and production scheme on ultimate recovery and production behaviors of a gas condensate sandstone.
Hydrocarbon liquid dissolved in saturated natural gas that comes out of solution when the pressure drops below the dewpoint. Natural gas condensate sweet is extremely flammable and can cause eye, skin, gastrointestinal, and respiratory irritation as well as dizziness and loss of balance. Start studying lecture 11 exam notes reservoir fluid sampling. A gas condensate with low condensate formation in the reservoir. Gas condensate is transported by trucks to refineries in salt lake city, utah. This work describes a method for estimating reservoir fluid. Simulation study of enhanced condensate recovery in a gas. Interpretation of the unusual fluid distribution in the yufutsu gascondensate field kassem ghorayeb, spe, and abbas firoozabadi, spe, reservoir engineering research inst. The reservoir temperature is such that it falls between the temperature of the critical point and the cricondentherm. Gascondensate reservoir article about gascondensate. Jan 30, 2016 chapter 5, part 1 of the online course in applied petroleum reservoir engineering. Summary this paper presents a generalized equation of state eos that represents several widely used cubic eoss. Wet gas, condensate and natural gas liquids are all synonyms. The ultimate output of the model is basically comprised of gor prediction and the compositions of the gas and condensate surface effluents.
Appendix b includes some special physical and mathematical constants that are of particular interest in gas reservoir engineering. Spe 63087 guidelines for choosing compositional and blackoil. Pvt analysis indicates that the hawiyah jauf formation is a rich gas condensate reservoir and part of reservoir fluid exhibits the nearcritical behavior. A wetgas reservoir is defined as producing a single gas composition to the. The liquid is sometimes called by an older name distillate, and sometimes simply oil. Interpretation of the unusual fluid distribution in the yufutsu gas condensate field kassem ghorayeb, spe, and abbas firoozabadi, spe, reservoir engineering research inst. Introduction landfill gas lfg condensate is a liquid produced in landfill gas collection sys tems. Determination of original gas condensate composition in. Except where otherwise noted, content on this site is licensed under a creative commons attributionnoncommercialsharealike 4. Simulation study of enhanced condensate recovery in a gascondensate reservoir iranian journal of chemical engineering, vol. This video is considered as an educational video used for nonprofitable purpose for all petroleum and nonpetroleum students in bue the british university in egypt and any other user for. The condensate bank can be reduced with proper producing sequence, hence the productivity of the well can be improved. Modeling a rich gas condensate reservoir with composition.
Gas condensate reservoirs are the categories of hydrocarbon reservoirs. Dec 02, 2016 wet gas, condensate and natural gas liquids are all synonyms. Estimating reservoir composition for gas condensates and volatile. An outer region 3 exists when the reservoir pressure is greater than the initial gas dew point and contains only gas. Gas reservoirs lend themselves to easy calculation of the hydrocarboninplace through a general gas law equation. It is shown that both the temperature and composition of the injection fluids play a key role in the remediation of productivity and condensate recovery. In region 2, the condensate builds up and the composition of the. Condensate tank oil and gas activities this appendix provides the detailed documentation of the methods used to develop refined emission factors for volatile organic compounds emissions from condensate storage tanks. As a result, different flow regions with different characteristics are created within the reservoir. A second case is cycling above dewpoint or depletion of a gas condensate reservoir. These occur if the reservoir conditions allow the hydrocarbons to exist as a gas.
Natural gas condensate is a lowboiling mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields if the raw gas temperature is reduced to below its hydrocarbon dew point, the liquids begin to condense out of the gas. Reservoir core analysis, including analysis under thermobaric conditions. What is the difference between a wet gas and a condensate gas. Fluid flow in gas condensate reservoirs usually exhibit complex flow behavior when the flowing bottomhole pressure drops below the dewpoint. However, calculation of hydrocarboninplace of a gascondensate reservoir is more complex because of the change from a single gaseous phase in the reservoir to two phases gas and condensate at the surface.
Composition of gas condensate knowledge of the gas liquid ratlo and the gravity of the lcluid s not sufficient to describe the composi tion of gas condensate for all purposes. Reservoir that yield natural gas can be classified into essential four categories, these are. A commercial simulator was then used to carry out numerical reservoir simulation of fluid flow in the north field. Compositional modeling of gascondensate reservoirs. Measurement of the final lowpressure condensate composition allows an important. This courseware module is part of penn states college of earth and mineral sciences oer initiative. Mak, in handbook of natural gas transmission and processing. A few examples of potential problems include recombining the gas and liquid samples at an incorrect ratio, changing production conditions prior to or during sampling and commingling zones with different properties. One correlation predicts dry gas production the other predicts condensate liquid production. Hence, the gas condensate, which is a supercritical fluid, enters the wde at the dew point pressure. What is the difference between a wet gas and a condensate. Pdf production performance of gas condensate reservoirs. When a condensate gas reservoir with gaseous water under high temperature and high pressure condition is producing, the gaseous water and nonequilibrium effect will have great influences on the phase behavior of condensate oil and gas system and the accumulation of condensate liquid near the wellbore area.
Abstract this work describes a method for estimating reservoir fluid composition for gas condensates and volatile oils from readily available field data. Without composition information and consideration for volume shrinkage due to molecular mixing, it is more difficult to predict precise changes in volume due to changes in temperature. This case is described in detail in the following sections. Production data analysis of tight gas condensate reservoirs. Shift factors3 are included to account for volume translation. Spe 63087 guidelines for choosing compositional and black. The feasibility of different methods such as periodic hot gas injection and gas reinjection using horizontal wells were assessed using different reservoir fluid and injection conditions. Jasmine, a gas condensate reservoir, is located 240km south east of the coast of aberdeen and is expected to start production at the end of 2012. The condensate is removed as the lfg is withdrawn from landfills. Simulation and well testing approaches khaksar manshad, abbas, mohammadi, hossein on. The first step of the study involved gathering north field reservoir data from previously published papers. This book is conflated based on the last scientific researches by authors and according to the last books and articles which are published in. Gas condensate fields is a single subsurface accumulation of gaseous hydrocarbons including gasoline and kerosene vapors and, less frequently, components with a higher molecular weight.
Natural gas condensate petroleum 64741475 100 nhexane 110543 1126 toluene 108883 06 benzene 71432 12 composition comments all concentrations are in percent by weight unless ingredient is a gas. Ngl vs lng vs lpg vs natural gas vs condensate natural gas liquids natural gas liquids ngls vs lpg vs lng talk about alphabet soup. Modelling and simulation of a gas condensate reservoir. Fundamentals of gas reservoir engineering, volume 23 1st. Produc tion of condensate may be through natural or artificial cooling of the gas or through physical processes such as volume ex pansion. The structure is a textbook example of a stratigraphic trap in which the devonian. Study on nonequilibrium effect of condensate gas reservoir. For gas condensate reservoirs the composition of the well stream during the depletion process changes with time and differs from the reservoir. A dry gas reservoir is defined as producing a single composition of gas that is constant in the reservoir, wellbore, and leaseseparation equipment throughout the life of a field. Region 2 where condensate and gas are present but only the gas is mobile.
Interpretation of the unusual fluid distribution in the. Physical principles of oil production, 1st ed mcgrawhill book. Fluid 3 is a real rich gascondensate fluid model and consists of 9 pseudo components with a maximum liquiddropout of 0. The term wet gas is sometimes used as more or less equivalent to gas condensate. Calculating well deliverability in gas condensate reservoirs robert mott aea technology, winfrith, dorchester, dorset dt2 8dh, united kingdom abstract well deliverability in most gas condensate reservoirs is reduced by condensate banking when the well bottom hole pressure falls below the dew point, although the impact of condensate banking. In this work we propose two new vogeltype inflow performance relations or ipr correlations for gascondensate reservoir systems. Production with gor 100,000 scfbbl is commonly called lean or dry gas.
Chapter 5, part 1 of the online course in applied petroleum reservoir engineering. Gas condensate is a hydrocarbon liquid stream separated from natural gas and consists of highermolecularweight hydrocarbons that exist in the reservoir as constituents of natural gas but which are recovered as liquids in separators, field facilities, or gas processing plants. Natural gas condensate encyclopedia article citizendium. Natural gas condensate article about natural gas condensate.
However, calculation of hydrocarboninplace of a gas condensate reservoir is more complex because of the change from a single gaseous phase in the reservoir to two phases gas and condensate at the surface. Analysis of individual and group hydrocarbon composition. Summary it is generally believed that at steady state, a heavy fluid mixture. Composition variation during flow of gascondensate wells. Typically, gas condensate contains hydrocarbons boiling up to c 8 fig. The development of gascondensate reservoirs by gas injection is treated in chapter 12. The use of well test analysis for quantifying near well and reservoir behavior is well. Oct 11, 2017 these conditions are favor able for the gas condensate mixture to be completely in the gaseous state in the reservoir. Initially, the fluids are in an indeterminate vapour. Well testing in gascondensate reservoirs stanford university.
To highlight the important properties used to characterize natural gas and condensate systems. Ron terry discusses gas condensate reservoirs, calculating hydrocarbon in place. Ngl vs lng vs lpg vs natural gas vs condensate natural gas liquids natural gas liquids ngls vs lpg vs lng talk about alphabet soup ngl vs lng vs l. Once an accurate model was obtained, the following three solutions to. Manual adjustments of eos parameters such as binary interaction. Gas reservoir management training course petroskills grm.
In this chapter, gas reservoirs have been divided into three groups. Calculating well deliverability in gas condensate reservoirs. More serious health effects can occur if condensate is inhaled or swallowed. Reservoirs with the relative amount of at least 5 to 10 grams of condensate per cubic meter are. Highoctane petrol, as well as jet, diesel, and boiler fuels are produced from gas condensate. The reservoir fluid samples collected during the developmental drilling show a high degree of variability in gas composition as well as condensate yields. New inflow performance relationships for gas condensate. Michael adewumi, vice provost for global program, professor of petroleum and natural gas engineering, the pennsylvania state university. Natural gas condensate sweet may contain variable amounts of benzene and nhexane. Petrochemical processing of gas condensate involves obtaining aromatics, olefins, and other monomers small molecules that are used in the production of plastics, synthetic rubbers, fibers, and resins. Pdf experimental study of composition variation during flow of. This case study investigated the effects of formation reservoir properties, aquifer influx, and production scheme on ultimate recovery and production behaviors of a gascondensate sandstone. Estimating reservoir composition for gas condensates and volatile oils from.
The compositional case optionally uses tabular kvalues versus p, rather than equation of state fugacitybased kvalues. The well tested at 25 million cubic feet of natural gas per day and over 2,000 bbls of condensate per day. Gas condensate is a hydrocarbon liquid stream separated from natural gas and consists of highermolecularweight hydrocarbons that exist in the reservoir as constituents of natural gas but which are recovered as liquids in separators, field facilities, or gasprocessing plants. For gas reservoirs and in some cases for gascap gas, the condensate is. To present the most popular models for estimating properties of natural gas and condensate systems. Determination of original gas condensate composition in the. Gas condensate production may be thought of as a type intermediate between oil and gas. How does a company optimize development of a gascondensate. These flow regions can be identified by well test interpretation. The composition and properties of the recombined analysis are used for reservoir. In certain cases, the assumption of fixed oil and gas composition is no longer valid.