Natural gas processing reservoir fluids and their phase d duration. The compressibility factor and dewpoint pressure were. Rich gas condensaterichrich gas condensate gas condensate 0 0. Increasing well productivity in gas condensate wells in qatars north field. Analysis of vapour liquid equilibria in unconventional. Apr 22, 2012 condensate to gas ratio cgr plays an important role in sales potential assessment of both gas and liquid, design of required surface processing facilities, reservoir characterization, and modeling of gas condensate reservoirs. Critical evaluation of empirical gas condensate correlations.
Gas condensate reservoirs stand as new frontiers as the petroleum industry is currently undergoing unprecedented surge of activities in securing enough hydrocarbon resources to satisfy the market. Presently, gas condensate reservoirs experience reductions in productivity by as much as a factor of 10 due to the dropout of liquid close to the wellbore. Appendix b includes some special physical and mathematical constants that are of particular interest in gas reservoir engineering. Simulation study of enhanced condensate recovery in a gas. Fully compositional integrated subsurfacesurface modeling. Developing a rapid and inexpensive technique to accurately estimate cgr. 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. Wettability alteration to intermediate gaswetting in low. This article is a synopsis of paper spe 59773, investigation of well productivity in gascondensate reservoirs, by a. In contrast, gas condensate reservoirs will always produce gas mixed with condensate, with the quantity of condensate varying from one reservoir to another.
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. Most known retrograde gascondensate reservoirs are in the range of 3000 to 8000 psi and 200400. The study revealed that the dry gas injection into gas condensate reservoirs minimized the dew point pressure by 18. Among them, gas injection techniques have been used as options to prevent retrograde condensation by vaporizing condensate andor by enhancing condensate recovery in gascondensate reservoirs. The need for integration had been recognized earlier particularly for gas condensate reservoir, gas cycling processes, and volatile oil systems. Gas condensate reservoirs differ from dry gas reservoirs. In gas condensate reservoirs, by reservoir depletion, pressure decreases below the dew point pressure of the fluid and condensate forms in the reservoir.
Some gas species within the raw natural gas will condense to a liquid state if the temperature is reduced to below the hydrocarbon dew point temperature at a set pressure. A major question in the use of the blackoil model is whether the twocomponent description can represent ade quately the compositional phenomena active during the depletion or the cycling of gas condensate reservoirs. This question is especially pertinent to nearcritical or very rich gas. 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. Gas condensate reservoirs are the categories of hydrocarbon reservoirs. Wells in tight sandstone condensate gas reservoirs of east china sea often suffer from dramatic production declines after being closed for several days. The calculations use results from cce and cvd experiments. At discovery, these reservoirs are often in single phase. Pdf on sep 10, 2015, ali vatani and others published gas condensate reservoir engineering find, read and cite all the research you need on researchgate. Often times, it is safe to assume that reservoir fluid behavior is only a function of pressure and independent of. Condensate blockage study in gas condensate reservoir. Lean gas condensateleanlean gas condensate gas condensate rich gas condensaterichrich gas condensate gas condensate 0 0. Apr 24, 2018 due to the increasing demand for gas consumption during cold seasons, it is a sense of urgency to provide a reliable resource for gas supply during these periods.
This paper presents the analysis of gas condensate field a development optimization with the purpose of maintaining constant gas production at the 20 level for 8 years taking into account mentioned factors. Calculating well deliverability in gas condensate reservoirs, 10. The feasibility analysis of underground gas storage during. Gascondensate flow modelling for shale gas reservoirs. The reservoir rock must be permeable and porous to contain the gas, and it has to be capped by impervious rock in order to form an effective seal that prevents the gas from escaping upward. Constantcomposition expansion tests were performed to determine the phase behavior and volumetric properties of reservoir fluid using an ultrahighpressure fluid pvt test system. The development of gas condensate reservoirs by gas injection is treated in chapter 12. Condensatetogas ratio cgr plays an important role in sales potential assessment of both gas and liquid, design of required surface processing facilities, reservoir characterization, and modeling of gas condensate reservoirs. Experiments and modeling of volumetric properties and.
Laboratory modelling on enchanced gas and condensate recovery. Gascondensate reservoirs exhibit different thermodynamic and flow behavior and the. Depleted gas condensate reservoirs can be revitalized by gas injection. Appendix a lists the commonly used units in gas reservoir engineering, along with their conversion factors. Gas reservoirs lend themselves to easy calculation of the hydrocarboninplace through a general gas law equation. Hence, the gas condensate, which is a supercritical fluid, enters the wde at the dew point pressure.
A composition stream from reservoir to the market has been obtained as a result of upstream, midstream and downstream retrograde gascondensate models. Africa subsahara total reported a naturalgascondensate discovery on block 11b12b in the outeniqua basin, 175 km offshore southern south africa. Gas reservoir, in geology and natural gas production, a naturally occurring storage area, characteristically a folded rock formation such as an anticline, that traps and holds natural gas. Condensate dropout occurs in the reservoir as the pressure. Understanding of phase and fluid flow behavior relationships is essential if we want to make accurate engineering computations for gas condensate systems e. Fully compositional integrated subsurfacesurface modeling for critical gas condensate reservoirs. Prediction of condensatetogas ratio for retrograde gas. J petrol explor prod technol wettability alteration to intermediate gaswetting in lowpermeability gascondensate reservoirs shuo zhang 0 1 guancheng jiang 0 1 le wang 0 1 wang qing 0 1 haitao guo 0 1 xinguo tang 0 1 diangang bai 0 1 0 h. Natural gas condensate, also called natural gas liquids, is a lowdensity mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields.
The cost and risk to develop reservoirs under these extreme conditions highlights the need to be able to confidently predict the recovery of gas and liquids. The objectives of this comprehensive research entail reservoir core analysis, reservoir fluid study, investigation and optimization of improved condensate recovery during gas storage processes in one of iraniandepleted fractured gas. Field work and laboratory determination of cgr is both time consuming and resource intensive. Phase change tracking approach to predict timing of condensate. Us4765407a us06902,247 us90224786a us4765407a us 4765407 a us4765407 a us 4765407a us 90224786 a us90224786 a us 90224786a us 4765407 a us4765407 a us 4765407a authority us.
Phase behavior is relevant to every aspect of petroleum and natural gas engineering. Flow behavior of gascondensate wells stanford earth. During reservoir depletion liquid condense out of the gas. Understanding of phase and fluid flow behavior relationships is essential if we want to make accurate engineering computations for gascondensate systems e.
Gas condensate reservoirs represent a vital source of hydrocarbon reserves which have been recognized as a reservoir type, possessing the most complex flow and thermodynamic behaviors. In a retrograde gas condensate reservoir middle, temperature is below the cricon dentherm, causing oil to condense as pres sure decreases. Gas injection techniques for condensate recovery and. According to the complexity of the reservoir fluid phase behavior, reservoir modeling is classified under two distinct groups. Data from 17 fields are included in this paper to demonstrate that severe loss of gas recovery occurs primarily in low productivity reservoirs. Dur ing the production phase of gas condensate reservoir multi phase fluid problem.
Optimization of gas condensate field a development on the. Well productivity is a critical issue in the development of many gas condensate reservoirs. To optimize the development of the filed, an integrated model was created. Gas condensate is a lowdensity mixture of liquid hydrocarbons that are present as gaseous components in the natural gas.
Pdf gas condensate pseudopressure in layered reservoirs. Due to the increasing demand for gas consumption during cold seasons, it is a sense of urgency to provide a reliable resource for gas supply during these periods. Ding zhu condensate blockage negatively impacts large natural gas condensate reservoirs all over the world. The study also investigates the performance of various reservoir fluid thermodynamic conditions, injection design variables, and economic. For example, the gas production of target well b1, studied in this paper plummeted from 50,000 to 0 m3d after the typhoon. Operators realise, however, that applying accumulated knowledge about conventional gas oil systems in gas condensate reservoirs without. Prerequisites and linking courses a good general knowledge of reservoir engineering is assumed through your own work, or having attended n933. Fundamentals of gas reservoir engineering, volume 23 elsevier. A new reservoir protection technology for offshore.
In contrast, gascondensate reservoirs will always produce gas mixed with condensate, with the quantity of condensate varying from one reservoir to another. The reservoir rock must be permeable and porous to contain the gas, and it has to be capped by impervious rock in order to form an effective seal that. Modeling and optimization of the rich gascondensate reservoir. Gas reservoir management training course petroskills grm. The selected solvent, isopropyl alcohol, and its mixture with methanol caused the removing of condensate blockage, condensate accumulation delay and increment of gas productivity. Condensate and gas recovery from a gas condensate reservoir produced by depletion 2. Well productivity in gascondensate reservoirs onepetro. Carbon dioxide is a promising injection fluid in gas condensate reservoirs due to large density and viscosity difference between gas condensate r esident gas and co2 i njection fluid that effectively will help to enhance gas recovery avoiding mixing, a main concern for degradation of value of remaining resident gas. The brulpadda well encountered 57 m of net gas condensate pay in lower cretaceous reservoirs.
Gas condensate reservoirs usually exhibit complex flow behaviors due to the buildup of condensate banks around the wells when the bottomhole pressure drops below the dew point. Gas condensate reservoirs are distinguished by producing both gas and condensate liquid at the. Natural gas processing reservoir fluids and their phase d. To model the condensate banking or water influx effects on gascondensate reservoirs, both cartesian and radial models have been used in the. A new multiphase model to analyze gas condensate production data is presented.
Effect of dry gases injection into egyptian gascondensate. J petrol explor prod technol wettability alteration to intermediate gas wetting in lowpermeability gas condensate reservoirs shuo zhang 0 1 guancheng jiang 0 1 le wang 0 1 wang qing 0 1 haitao guo 0 1 xinguo tang 0 1 diangang bai 0 1 0 h. A production data analysis model for gascondensate reservoirs. Us3149668a gas recovery from gas condensate reservoirs. According to the previous studies, the addition of some nitrogen causes a considerable increase in mixture dew. Phase behavior, dew point pressure and maximum recovery are studied after and before injection. Naturalgas condensate, also called natural gas liquids, is a lowdensity mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields.
This book is conflated based on the last scientific researches by authors and according to the last books and articles which are published in fundamentals of reservoirs engineering. Petroleum reservoirs are broadly classified as conventional and unconventional reservoirs. Early developments in reservoir engineering analysis relied on zerodimensional or tank material balances for the evaluation and forecasting of reservoir performance. Simulation study of enhanced condensate recovery in a gascondensate reservoir iranian journal of chemical engineering, vol. Hydrocarbon liquid dissolved in saturated natural gas that comes out of solution when the pressure drops below the dewpoint. 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. At the time of discovery, gas condensates are often found as singlephase gas in the reservoir.
The course is designed for mid to senior level reservoir and production engineers involved in the evaluation, planning and development of gas condensate reservoirs. Gas condensate pvt petroleum reservoir pressure free 30. In conventional reservoirs, the naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower. The development of gascondensate reservoirs by gas injection is treated in chapter 12. Method of producing gas condensate and other reservoirs en us06902,247 19860828. Gascondensate reservoirs differ from drygas reservoirs. Gas condensate reservoirs in niger delta and around the world are becoming increasingly important as a result of additional liquid recovery and increasing demand for light oil and natural gas.
Pdf well productivity estimation in gas condensate reservoirs is still a challenge. Producing the gas to separator conditions creates a mixture of gas and condensed oil. Liquid buildup around the well can cause a significant reduction in productivity, even in lean gas condensate reservoirs where the maximum liquid drop. The reason is 1 to get an accurate and consistent estimate of the initial gas and condensate in place, and 2 to accurately predict the gas and condensate recovery as a function of pressure during depletion drive. Gas recovery from gas condensate reservoirs download pdf info publication number us3149668a. Gas condensate pseudopressure in layered reservoirs. Laboratory modelling on enchanced gas and condensate. Abstract ten years of operation of gascondensate reservoirs has verified the necessity for and practicability of cooperative and unitized operation. Simulation study of enhanced condensate recovery in a gas condensate reservoir iranian journal of chemical engineering, vol. Following success at the main objective, the well was deepened to a final depth of 3633 m.
The objectives of this comprehensive research entail reservoir core analysis, reservoir fluid study, investigation and optimization of improved condensate recovery during gas storage processes. Four reservoir samples under ultrahighpressure and hightemperature conditions were collected from condensate gas fields in china. Us4765407a method of producing gas condensate and other. Its presence as a liquid phase depends on temperature and pressure conditions in the reservoir allowing condensation of liquid from vapor. Gas condensate pvt petroleum reservoir pressure free. The results assume no aquifer influx and ignore the effect of rock and water compressibility. Bai tan hai development company, china national petroleum corporation, tianjin 300289, china 1 s. Pdf gas condensate reservoir engineering researchgate. Partners are qatar petroleum with 25%, canadian natural resources with 20%, and main street, a south african consortium, with 10%. A case study of gascondensate reservoir performance under bottom. Depending on objective and availability, different injection gases have been suggested and tested for gas injection enhanced gas recovery egr, most frequently dry hydrocarbon gas, carbon dioxide or carbonated natural gas and nitrogen are considered.
Production with gor 100,000 scfbbl is commonly called lean or dry gas. Pdf understanding the behaviors of gas condensate reservoirs. The feasibility analysis of underground gas storage during an. Calculating well deliverability in gas condensate reservoirs, 10 th european symposium on improved oil recovery. Method of producing gas condensate and other reservoirs download pdf info publication number us4765407a. Santa barbara and pirital fields, venezuela abstract this paper presents the workflow and learned lessons during the construction of a fully compositional integrated subsurfacesurface model for the santa barbara and pirital fields, which are. Sep 27, 20 gas condensate reservoirs part 1 duration. Gascondensate reservoirs represent an important part of these resources. This is a pdf file of an unedited manuscript that has been accepted for publication. Some gas species within the raw natural gas will condense to a liquid state if the temperature is reduced to below the hydrocarbon dew point.
Calculating well deliverability in gas condensate reservoirs. A petroleum reservoir or oil and gas reservoir is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. The depletion of rich, gas condensate reservoirs to pressures significantly below the dew point is a topic of increasing interest as deeper, hotter hydrocarbon reservoirs are exploited. Condensate blockage study in gas condensate reservoir pdf. To evaluate the effect of reservoir pe rmeability on gas condensate blockage, the reservoir permeability was.
886 1031 108 777 1170 731 159 1526 186 1027 1561 1013 658 966 294 501 951 1265 1471 1094 1232 1009 1226 1014 1321 596 658 804 968 690 1261