scholarly journals Characteristics and quantitative study on gas breakthrough in developing Yaha-2 condensate gas reservoir in Tarim Basin, China

2018 ◽  
Vol 36 (4) ◽  
pp. 787-800
Author(s):  
Jing Xia ◽  
Pengcheng Liu ◽  
Yuwei Jiao ◽  
Mingda Dong ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Tarim Basin ◽  
Prediction Models ◽  
Graphical Representation ◽  
Gas Injection ◽  
Dew Point ◽  
Breakthrough Time ◽  
Sweep Efficiency ◽  
Reservoir Properties ◽  
Gas Reservoir ◽  
Point Pressure

In order to keep the formation pressure be larger than the dew-point pressure to decrease the loss of condensate oil, cyclic gas injection has been widely applied to develop condensate gas reservoir. However, because the heterogeneity and the density difference between gas and liquid are significant, gas breakthrough appears during cyclic gas injection, which apparently impacts the development effects. The gas breakthrough characteristics are affected by many factors, such as geological features, gas reservoir properties, fluid properties, perforation relations between injectors and producers, and operation parameters. In order to clearly understand the gas breakthrough characteristics and the sensitivity to the parameters, Yaha-2 condensate gas reservoir in Tarim Basin was taken as an example. First, the gas breakthrough characteristic of different perforation relations by injecting natural gas was studied, and the optimal relation was achieved by comparing the sweep efficiency. Then, the designs of orthogonal experiments method were employed to study the sensitivity of gas breakthrough to different parameters. Meanwhile, the characteristic parameters, such as gas breakthrough time, dimensionless gas breakthrough time, and sweep volume, were calculated and the prediction models were achieved. Finally, the prediction models were applied to calculate the gas breakthrough time and sweep volume in Yaha-2 condensate gas reservoir in Tarim Basin. The reliability of the model was verified at the same time. Please see the Appendix for the graphical representation of the abstract.

Equilibrium Revaporization of Retrograde Condensate By Dry Gas Injection

1968 ◽  
Vol 8 (01) ◽  
pp. 87-94 ◽  
Author(s):  
Lowell R. Smith ◽  
Lyman Yarborough
Keyword(s):  
Gas Flow ◽  
Water Saturation ◽  
Gas Injection ◽  
Gas Condensate ◽  
Dew Point ◽  
Reservoir Pressure ◽  
Sweep Efficiency ◽  
Flowing Fluid ◽  
Condensate Reservoir ◽  
Gas Cycling

Abstract This paper presents results of a laboratory study of retrograde condensate recovery by revaporization into dry injection gas. Flow tests were performed in 10.6-ft long sandpacks at 100F and 1,500 psi. In three runs methane revaporized the liquid from a n-heptane-methane mixture in the presence of immobile water. Two of these tests were water-wet, and the third was totally oil-wet. In the three runs n-heptane recovery was complete after 2.5 hydrocarbon PV of injection. There was no significant performance difference between the two wettability extremes. In a fourth experiment, a methane-hydrogen sulfide mixture revaporized a synthetic light, sour condensate. No water saturation was present. Equilibrium compositions and volumetric data were obtained for the four-component condensate. The heavy component, n-heptane, was removed alter 6 PV production. Comparison of the effluent fluid compositions with known equilibrium data shows that the flowing fluid was equilibrium vapor and that the mixing zone between equilibrium vapor and dry injection gas was short. Data indicated that complete recovery of retrograde liquid occurred after it was contacted by a sufficient quantity of dry gas. Introduction When pressure declines below the fluid dew point in a gas condensate reservoir, a liquid phase forms. In this process, referred to as retrograde condensation, the quantity of liquid formed is frequently small enough that the liquid is not a flowing phase. To prevent loss of valuable retrograde liquids, the process of dry gas cycling has been employed for several years as a more or less standard practice. In this procedure the reservoir pressure is maintained above the fluid dew point so that the liquid components may be produced as vapor and then separated at the surface. Although full pressure maintenance by gas cycling seems ideal in terms of preventing liquids loss, several factors can reduce the attractiveness of such an operation. From a study of a condensate reservoir in Alberta, Canada, Havlena et al. concluded that cycling under conditions of declining pressure leads to economic advantages and to a high recovery of hydrocarbon liquids. This study considered effects of volumetric sweep efficiency, retrograde behavior of the original wet gas and revaporization characteristics of the retrograde liquid when contacted by dry gas. The first major work concerning revaporization of liquid in a gas condensate system is that of Standing et al. Calculations based upon the PVT behavior of a recombined gas condensate fluid indicated that all retrograde liquid can be recovered if it is contacted by a sufficient quantity of dry gas. The paper considered the effect of variable permeability upon the recovery of retrograde liquid. Standing et al. concluded that recovery of heavier components in the retrograde liquid is greatest if reservoir pressure is allowed to decline below the dew point prior to dry gas injection. Since the work of Standing et al., several laboratory studies have been reported which show that recovery of hydrocarbon liquids by vaporization into dry injected gas can contribute to increased recovery above that obtained by ordinary production practices. Vaporization from retrograde condensate, conventional oil and volatile oils reservoirs has been considered. There is little work that deals with revaporization recovery from condensate reservoirs. SPEJ P. 87ˆ

The Effects of Interfacial Tension Dependent Relative Permeability on Sweep Efficiency and Oil Recovery Under Different Gas Injection Composition

2021 ◽  
Author(s):  
Mohd Ghazali Abd Karim ◽  
Wahyu Hidayat ◽  
Alzahrani Abdulelah
Keyword(s):  
Interfacial Tension ◽  
Simulation Model ◽  
Relative Permeability ◽  
Oil Recovery ◽  
Gas Injection ◽  
Sweep Efficiency ◽  
Reservoir Properties ◽  
Relative Permeability Curve ◽  
Compositional Model ◽  
The Impact

Abstract The objective of this paper is to investigate the effects of interfacial tension dependent relative permeability (Kr_IFT) on oil displacement and recovery under different gas injection compositions utilizing a compositional simulation model. Oil production under miscible gas injection will result in variations of interfacial tension (IFT) due to changes in oil and gas compositions and other reservoir properties, such as pressure and temperature. Laboratory experiments show that changes in IFT will affect the two-phase relative permeability curve (Kr), especially for oil-gas system. Using a single relative permeability curve during the process from immiscible to miscible conditions will result in inaccurate gas mobility against water, which may lead to poor estimation of sweep efficiency and oil recovery. A synthetic sector compositional model was built to evaluate the effects of this phenomenon. Several simulation cases were investigated over different gas injection compositions (lean, rich and CO2), fluid properties and reservoir characterizations to demonstrate the impact of these parameters. Simulation model results show that the application of Kr_IFT on gas injection simulation modelling has captured different displacement behavior to provide better estimation of oil recovery and identify any upside potential.

scholarly journals Condensate banking removal: study on ultrasonic amplitude effect

2021 ◽  
Author(s):  
Aieshah Ainuddin ◽  
Nabilla Afzan Abdul Aziz ◽  
Nor Akmal Affandy Mohamed Soom
Keyword(s):  
Negative Impact ◽  
Cost Effective ◽  
Gas Condensate ◽  
Drop Out ◽  
Dew Point ◽  
Productivity Index ◽  
Sweep Efficiency ◽  
Condensate Reservoir ◽  
Point Pressure ◽  
Dew Point Pressure

AbstractHydrocarbons in a gas condensate reservoir consist of a wide variety of molecules which will react varyingly with the change of pressure inside the reservoir and wellbore. The presence of heavier ended hydrocarbons such as C5 and above, condensate banking will occur as pressure depletes. Pressure drop below dew point pressure causes condensate buildup which will give a negative impact in the productivity index of a gas condensate reservoir. Gas condensate reservoirs experience liquid drop out when pressure depletion reaches below dew point pressure. This occurrence will eventually cause condensate banking over time of production where condensate builds up in pore spaces of near-wellbore formations. Due to increase in condensate saturation, gas mobility is reduced and causes reduction of recoverable hydrocarbons. Instead of remediating production loss by using unsustainable recovery techniques, sonication is used to assist the natural flow of a gas condensate reservoir. This study aims to evaluate the effects of various ultrasonic amplitudes on condensate removal in a heterogenous glass pack in flowing conditions with varying exposure durations. Experiments were conducted by using n-Decane and a glass pack to represent condensate banking and near-wellbore area. Carbon dioxide was flowed through the pack to represent flowing gas from the reservoir after sonication of 10%, 50% and 100% amplitudes (20 kHz and 20 Watts). Analysis of results shows recovery of up to 17.36% and an areal sweep efficiency increase in 24.33% after sonication of 100% amplitude for 120 min due to reduction in viscosity. It was concluded that sweeping efficiency and reciprocal mobility ratio are increased with sonication of 100% amplitude for 120 min. This indicates that mobility of n-Decane is improved after sonication to allow higher hydrocarbon liquid production. Insights into the aspects of the mechanical wave are expected to contribute to a better understanding of tuning the sonic wave, to deliver remarkable results in a closed solid and fluid system. This form of IOR has not only proved to be an effective method to increase productivity in gas condensate wells, but it is also an environmentally sustainable and cost-effective method.

scholarly journals INJEKSI FOAM SEBAGAI TERTIARY OIL RECOVERY

PETRO ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 51
Author(s):  
Iwan Setya Budi ◽  
Agus Rudiyono ◽  
Astra Pramana Astra Pramana
Keyword(s):  
Oil Recovery ◽  
Flue Gas ◽  
Gas Injection ◽  
Sweep Efficiency ◽  
Gas Reservoir ◽  
Recovery Method ◽  
Tertiary Oil Recovery ◽  
Hydrocarbon Gas ◽  
Tertiary Recovery ◽  
Reduce Carbon Emission

<p><em>Foam injection is a variance of gas flood as tertiary recovery method designed to mitigate low sweep efficiency normally found in gas flood due to inheritance of density difference between injected gas and oil which often severed by presence of reservoir heterogeneity (permeability contrast in this case). Foam EOR has two goals: (1) improve oil recovery by promoting better sweep efficiency, and (2) reduce carbon emission related to global warming issue provided that the injectant gas used is CO2, hydrocarbon gas or flue gas.. Reservoir simulation performed is able to show recovery improvement of foam compared to continuous gas injection.</em></p>

A Beta-Type Reservoir Simulator for Approximating Compositional Effects During Gas Injection

1974 ◽  
Vol 14 (05) ◽  
pp. 471-481 ◽  
Author(s):  
R.E. Cook ◽  
R.H. Jacoby ◽  
A.B. Ramesh
Keyword(s):  
Gas Injection ◽  
Gas Condensate ◽  
Dew Point ◽  
Fluid Composition ◽  
Fluid Systems ◽  
Fluid Properties ◽  
Compositional Simulator ◽  
Point Pressure ◽  
Compositional Effects ◽  
Reservoir Simulator

Abstract This paper presents the formulation and applications of a two-dimensional two-phase beta-type numerical model for simulating oil and gas reservoir performance where fluid compositional effects are significant. The model utilizes PVT data as functions of pressure and a compositional parameter to reflect changes in fluid composition parameter to reflect changes in fluid composition resulting from dry gas injection. The model differs from previous beta-type simulators for approximating compositional effects in that it accounts for the reduced tendency of oil to vaporize as light ends are removed by continued contact with dry gas. A simple linear compositional model is used to compute the changing fluid properties in each cell as injection gas mixes with in-place fluid during a series of constant pressure displacements. The simple-model data are correlated against the cumulative pore volumes of injected gas contacting each cell at various points in time for each pressure level. By tracking this parameter for each cell in the two-dimensional beta-type model the spatial and time variations of fluid properties with pressure and injection gas throughput are computed in the model from the correlations. Special provisions are included for gas condensate systems above their dew-point pressure and for reservoir oil systems above their bubble-point pressure. A comparison is made with results from a previously published fully compositional simulator. It is shown that, in addition to yielding quite similar computed compositional effects, the beta-type simulator attains an advantage in computing speed of at least 3 to 1 over a July compositional simulator. Example applications are presented for gas injection in an oil reservoir and for retrograde liquid recovery by dry gas sweep at a Pressure considerably below the dew point of a gas-condensate reservoir. Introduction Conventional beta-type numerical simulators have been used for many years to simulate the performance of so-called "black oil" reservoirs. The term "black oil" denotes oil of medium to heavy gravity at moderate temperature and pressure. Such oils can be reasonably approximated as binary fluid systems where the amount of gas dissolved in the oil is merely a function of reservoir pressure and temperature. For these systems the reservoir gas phase is assumed to contain no recoverable liquids phase is assumed to contain no recoverable liquids when flashed through surface separates. Moreover, the further assumption is made that injected gas combines with reservoir oil exactly as does in-place reservoir gas, disregarding compositional differences between the gas phases. For oils of higher gravity, existing at higher temperatures and pressures, the preceding assumptions become no longer valid. Not only does the reservoir gas phase contain a significant amount of vaporized stock-tank liquid, but injected gas can have a significant effect on the phase behavior of the reservoir hydrocarbon system. At the far end of the compositional spectrum, gas - condensate reservoirs contain the total stock-tank liquid in the vapor phase. Moreover, injected gas has a diluting effect on the liquid content as it mixes with reservoir gas. To account for the collects of mass transfer between the vapor and liquid phases, and the composition changes resulting from gas injection, several recent authors have developed fully compositional reservoir simulators. These simulators actually track individual components of a hydrocarbon fluid system, using equilibrium constants representative of the fluid compositions being studied. These fully compositional simulators are applicable to a much broader range of reservoir fluid systems than the conventional beta-type reservoir simulator. However, since the computing requirements are generally directly proportional to the number of hydrocarbon components used in the fluid system, they can be quite expensive to employ as a general purpose simulator. purpose simulator. SPEJ P. 471

Software Simulation and Experimental Study on Wax Deposition Pattern of Deep Condensate Gas

2019 ◽  
Author(s):  
Jie Wang ◽  
Fujian Zhou ◽  
Erdong Yao ◽  
Fan Fan ◽  
Lishan Yuan ◽  
...  
Keyword(s):  
Solid Phase ◽  
Dew Point ◽  
Wax Deposition ◽  
Deposition Pattern ◽  
Gas Reservoir ◽  
Software Simulation ◽  
Point Pressure ◽  
Simulation Results ◽  
Temperature And Pressure ◽  
Dew Point Pressure

Abstract The Bozi block of Tarim Oilfield is a typical tight sand condensate gas reservoir with serious wax plugging issue. It is necessary to study the phase behavior and the wax deposition pattern of well fluids in Bozi gas reservoir, which provides the phase enveloping diagram of the condensate gas and can help to control the paraffin deposition. In this study, the PVT tester and self-designed microscopic solid deposition tester are used to get the phase enveloping curve of the condensate gas, which is combined with software simulation results and production data of Bozi 104 well to analyze wax deposition from formation to wellbore, wellbore to ground and surface pipeline. The main conclusions and suggestions are as follows: with different temperature and pressure, condensate gas produces different phase regions such as gas phase, gas-liquid phase, gas-solid phase, gas-liquid-solid phase, etc. Above the dew point pressure, the WAT is less impacted from pressure while the WAT gradually decreases due to the dissolution effect below the dew point pressure. The experimental results are used to revise the software simulation results and then to obtain the phases of different temperature and pressure regions. The state envelope is used to predict the liquid separation and wax production situation at different production stages; the liquid condensation and waxing area of the Bozi 104 well lies in the surface pipeline behind the nozzle, where appropriate wax prevention measures are needed.

Fire modelling in Tasmanian buttongrass moorlands. III. Dead fuel moisture

2001 ◽  
Vol 10 (2) ◽  
pp. 241 ◽  
Author(s):  
Jon B. Marsden-Smedley ◽  
Wendy R. Catchpole
Keyword(s):  
Prediction Model ◽  
Regression Model ◽  
Fire Management ◽  
Prediction Models ◽  
Dew Point ◽  
Seasonal Effects ◽  
Experimental Program ◽  
Fuel Moisture ◽  
Fire Behaviour ◽  
Fire Modelling

An experimental program was carried out in Tasmanian buttongrass moorlands to develop fire behaviour prediction models for improving fire management. This paper describes the results of the fuel moisture modelling section of this project. A range of previously developed fuel moisture prediction models are examined and three empirical dead fuel moisture prediction models are developed. McArthur’s grassland fuel moisture model gave equally good predictions as a linear regression model using humidity and dew-point temperature. The regression model was preferred as a prediction model as it is inherently more robust. A prediction model based on hazard sticks was found to have strong seasonal effects which need further investigation before hazard sticks can be used operationally.

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