Initial oil in place calculation for solution gas drive reservoir duration. The operating method for each reservoir should be based upon the character istics of the gas condensate at reservoir conditions. Gas reservoirs can be classified into dry gas reservoirs, wet gas reservoirs and gas condensate reservoirs. Africa subsahara total reported a naturalgascondensate discovery on block 11b12b in the outeniqua basin, 175 km offshore southern south africa. The development of gascondensate reservoirs by gas injection is treated in chapter 12.
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. Gas condensate reservoir free download as pdf file. According to the previous studies, the addition of some nitrogen causes a considerable increase in mixture dew. Condensate and gas recovery from a gas condensate reservoir produced by depletion 2. A further complication of this problem is that the composition of the surface liquid also changes. The fluid selected for our study is a very rich gas condensate taken from cusiana field located 125 miles northeast of. Simulation study of enhanced condensate recovery in a gas. Members of the transport and energy processes division of aiche are entitled to this content for free.
Prediction of liquid hydrocarbon recovery from a gas. Shift factors3 are included to account for volume translation. Gas production from gas condensate reservoirs using. Gas injection techniques for condensate recovery and. A gas well is producing gas with a specific gravity of 0. Appendix a lists the commonly used units in gas reservoir engineering, along with their conversion factors. Spinfree cc2 implementation of induced transitions between.
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. At discovery, these reservoirs are often in single phase. In a gas condensate reservoir, the initial reservoir condition is in the singlephase area to the right of the critical point. 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. In fact, condensate gas reservoirs produce both condensate gas and. Understanding of phase and fluid flow behavior relationships is essential if we want to make accurate engineering computations for gascondensate systems e. The four layered variable thickness gas condensate reservoir has the grid and scal data scaledup from spe3 gas cycling of retrograde condensate reservoir available pvt data rich in. Introduction a recombined sample of reservoir fluid is placed in a pressure, volume, temperature i. Free gas recovery factor prediction for horizontal well as a function of. 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. Pore throat controlling liquid yield in shale mismatch between dry produced gas at surface and wet gas or condensate in the reservoir jeanyves d. The reason is 1 to get an accurate and consistent estimate of the initial gas and condensate in place, and 2 to accurately predict.
In a typical gas reservoir, gas is stored in the pores by compression. New chemical treatment for permanent removal of condensate. Gas zfactor muz standing would be happy to hear that the zfactor is still the only pvt property which always needs accurate determination in a gas condensate reservoir as in a dry gas reservoir. As the reservoir pressure is reduced, gas is desorbed from the surface of the matrix. The gas is much more mobile than the condensate and, therefore, the gascondensate ratios gcr exhibited at surface are commonly higher than that of the reservoir fluid.
Its presence as a liquid phase depends on temperature and pressure conditions in the reservoir allowing condensation of liquid from vapor. Naturalgas condensate wikipedia republished wiki 2. Under natural conditions, a gas condensate is a solution of heavier hydrocarbons. Pressure decline below the dew point pressure causes condensation to occur which creates a hydrocarbon liquid saturation in the reservoir. Flow behavior of gascondensate wells stanford university. A commercial simulator was then used to carry out numerical reservoir simulation of fluid flow in the north field.
A petroleum reservoir or oil and gas reservoir is a subsurface pool of hydrocarbons contained in porous or fractured rock formations. Optimization of gascondensate reservoir eor technology under. Gas reservoirs lend themselves to easy calculation of the hydrocarboninplace through a general gas law equation. Condensate dropout occurs in the reservoir as the pressure. In a retrograde gas condensate reservoir middle, temperature is below the cricon dentherm, causing oil to condense as pres sure decreases. In conventional reservoirs, the naturally occurring hydrocarbons, such as crude oil or natural gas, are trapped by overlying rock formations with lower permeability, while.
Improving gas condensate reservoir productivity aiche. The literature shows many differences between gas condensate reservoirs and dry gas reservoirsi6. Pore throat controlling liquid yield in shale mismatch. Gas condensate reservoirs are the categories of hydrocarbon reservoirs. It might happen in a lean gas condensate reservoir. The mbo model representation of compositional phenomena for a gas condensate reservoir proved to be successful in the following cases. Understanding the behaviors of gas condensate reservoirs. Condensate blockage study in gas condensate reservoir. In a cbmshale reservoir, in addition to the free gas g f stored in the fracture network, gas is stored within the coal shale matrix by adsorption.
Gulf professional publishing boston london auckland johannesbourg melbourne new delhi second edition reservoir eng fob 20011029 16. Rich gas condensaterichrich gas condensate gas condensate 0 0. Presently, gascondensate reservoirs experience reductions in productivity by as much as a factor of 10 due to the dropout of liquid close to the wellbore. Producing the gas to separator conditions creates a mixture of gas and condensed oil.
Gascondensate reservoirs differ from drygas reservoirs. Appendix b includes some special physical and mathematical constants that are of particular interest in gas reservoir engineering. Assume that the gas and condensate analyses given in figures 5. Pdf gas condensate reservoir engineering researchgate. In gas condensate reservoirs, condensate banking is one of the most. Reservoir that yield natural gas can be classified into essential four categories, these are. The condensate is not only generated into the reservoir, it is also formed when liquid drops out, or condenses, from a gas stream in pipelines or surface facilities. Kleinsteiber has over 24 years of petroleum engineering experience and has authored or coauthored papers dealing with production decline type curve analysis, co2 flooding, and depletion of a rich gas condensate reservoir by. Naturalgas condensate 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. Gascondensate reservoirs are distinguished by producing both gas and condensate liquid at the surface.
The composition and properties of the recombined analysis are used for reservoir calculations. Compositional modeling of gascondensate reservoirs. Petroleum reservoirs are broadly classified as conventional and unconventional reservoirs. The vapourvapour interface observation and appraisement of a. Figure 1 provides a fairly typical gor versus total flow rate response from a gas condensate reservoir.
The phase diagram e shows the r trograde gas must have a temperature higher than the critical temperature. The gas will drop out liquid by retrograde condensation in the reservoir, when the pressure falls below the dew point. Developing an easytouse simulator to thermodynamic. In this chapter, gas reservoirs have been divided into three groups. A gas condensate with low condensate formation in the reservoir when the bottomhole pressure is reduced below the dewpoint pressure.
The gascondensate content in gases of various deposits ranges from 12 to 700 cm3 per 1 m3 of gas. 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. The calculations use results from cce and cvd experiments. The production of condensate reservoirs can be complicated. Successful field implementation of a novel solidsfree system to control fluid loss during overbalanced workover. 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. Simulation study of enhanced condensate recovery in a gascondensate reservoir iranian journal of chemical engineering, vol. It is intended both for students who are new to the subject and practitioners, who may use this book as a reference and refresher. Condensate blockage might play an important role in reduction of the well deliverability of a gas condensate reservoir. Following success at the main objective, the well was deepened to a final depth of 3633 m. Gas flow tests have been used to study the effectiveness of each method to restore or maintain gas production for gas condensate reservoir. Typically, gas condensate contains hydrocarbons boiling up to c 8 fig.
Gascondensate reservoir article about gascondensate. This synthetic reservoir model of a single layer homogenous reservoir was generated. The depletion of gas condensate reservoirs to pressures below the dew point has been studied by reservoir engineers for many years. 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. The accumulation of liquid condensates around the production well can. Summary development of gascondensate reservoirs is a complicated problem by itself. K4 gas condensate, andviscosity were calculated by compositions of separatorgas liquid the model. One question often asked is during and after sampling.
The brulpadda well encountered 57 m of net gas condensate pay in lower cretaceous reservoirs. Pdf understanding gascondensate reservoirs navneet. Pdf well productivity estimation in gas condensate reservoirs is still a. Stanley kleinsteiber is a senior petroleum engineer with mha petroleum consultants inc.
Gascondensate reservoirs represent a vital source of hydrocarbon reserves which have been recognized as a reservoir type, possessing the most complex flow and thermodynamic behaviors. Gas condensate reservoir petroleum reservoir gases. Condensate is mainly composed of propane, butane, pentane and heavier hydrocarbon fractions. Condensate reservoirs are inherently more difficult to characterize correctly. Pdf understanding the behaviors of gas condensate reservoirs. The percentage of vapor decreases, but can increase again with continued.
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. When the pbhf is above dew point, the mw of the surface liquid is the highest. Early developments in reservoir engineering analysis relied on zerodimensional or tank material balances for the evaluation and forecasting of reservoir performance. Production with gor 100,000 scfbbl is commonly called lean or dry gas. The results assume no aquifer influx and ignore the effect of rock and water compressibility. Gascondensate reservoirs exhibit complex phase and flow behaviors due to the appearance of condensate banking in the near well region. 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. Gas condensate reservoirs are distinguished by producing both gas and condensate liquid at the. Once an accurate model was obtained, the following three solutions to.
A natural gas liquid with a low vapor pressure compared with natural gasoline and liquefied petroleum gas. In gas condensate reservoirs, the reservoir temperature lies between the critical temperature and the cricondentherm. 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. Other factors such as richness of the gas size of he reserve capaeitics of wells nature of the reservoir and mode of occurrence of the gas condensate must e.
Calculation of hydrocarboninplace volume of a gascondensate reservoir from the geologic, reservoir, and production data requires a clear understanding of the behavior of oil and gas under various reservoir and surface operating conditions. 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 the natural gas condensate is also called condensate. Gas reservoir management training course petroskills grm. The compositional case optionally uses tabular kvalues versus p. Chapter 5, part 1 of the online course in applied petroleum reservoir engineering. The need for integration had been recognized earlier particularly for gas condensate reservoir, gas cycling processes, and volatile oil systems. Killing fluid loss mechanism and productivity recovery in a gas. Pvt cell equations of state eos have been used in at a pressure above the dew point of 5iz0 psig and at. Pdf gas condensate reservoir performance free download as pdf file. Introduction gas condensate reservoirs mostly produce gas, with some liquid dropout, frequently occurring in the wellhead separators. The first step of the study involved gathering north field reservoir data from previously published papers.
1152 616 870 1118 1246 26 679 700 1356 705 1043 577 1087 1207 101 1156 882 91 1441 980 1427 1419 650 1210 1071 730 816 1037 1409 205 139 307 606 191 1008 150 1003