Wellbore-Storage Effects in Transient Flow Testing of Gas Wells (includes associated papers 19899 and 20008 )

1989 ◽  
Vol 41 (06) ◽  
pp. 623-632 ◽  
Author(s):  
J.S. Ahluwalia ◽  
J.O. Wilkes
Keyword(s):  
Transient Flow ◽  
Gas Wells ◽  
Wellbore Storage ◽  
Storage Effects

Changing Wellbore Storage Effects In Gas Well Testing

1997 ◽  
Author(s):  
S. Al-Haddad ◽  
M. LeFlore ◽  
T. Lacy
Keyword(s):  
Well Testing ◽  
Gas Well ◽  
Wellbore Storage ◽  
Storage Effects

IMPROVED CONVOLUTION ANALYSIS OF LATE WELLBORE STORAGE BUILDUP DATA OF GAS WELLS

1999 ◽  
Vol 17 (5-6) ◽  
pp. 577-605
Author(s):  
Ibrahim S. Nashawi ◽  
Reyadh A. Almehaideb
Keyword(s):  
Gas Wells ◽  
Wellbore Storage

scholarly journals Explicit Deconvolution of Well Test Data Dominated by Wellbore Storage

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
K. Razminia ◽  
A. Hashemi ◽  
A. Razminia ◽  
D. Baleanu
Keyword(s):  
Test Data ◽  
Material Balance ◽  
Early Time ◽  
Time Behavior ◽  
Well Test ◽  
Deconvolution Method ◽  
Pressure Data ◽  
Practical Applications ◽  
Wellbore Storage ◽  
Storage Effects

This paper addresses some methods for interpretation of oil and gas well test data distorted by wellbore storage effects. Using these techniques, we can deconvolve pressure and rate data from drawdown and buildup tests dominated by wellbore storage. Some of these methods have the advantage of deconvolving the pressure data without rate measurement. The two important methods that are applied in this study are an explicit deconvolution method and a modification of material balance deconvolution method. In cases with no rate measurements, we use a blind deconvolution method to restore the pressure response free of wellbore storage effects. Our techniques detect the afterflow/unloading rate function with explicit deconvolution of the observed pressure data. The presented techniques can unveil the early time behavior of a reservoir system masked by wellbore storage effects and thus provide powerful tools to improve pressure transient test interpretation. Each method has been validated using both synthetic data and field cases and each method should be considered valid for practical applications.

scholarly journals Analyzing of Drill Stem Test (DST) Result for Dual Porosity Limestone Reservoir

2017 ◽  
Vol 2 (3) ◽  
pp. 240-251
Author(s):  
Zheno Kareem Ahmed ◽  
Halkawt Ismail Ismail M-Amin
Keyword(s):  
Transient Flow ◽  
Double Porosity ◽  
Oil Field ◽  
Dual Porosity ◽  
Depth Interval ◽  
Reservoir Pressure ◽  
Well Test ◽  
Positive Skin ◽  
Skin Factor ◽  
Wellbore Storage

The aim of this paper is to discuss and evaluate the result of DST which was conducted in a limestone reservoir of an oil field at the depth interval 3764.29-3903.0 meter in well-1 to evaluate the dynamic characteristics of the reservoirs, for instance: skin effect, permeability, wellbore storage, reservoir boundary and average reservoir pressure. Reservoir Pressure profiles has been recorded for both Buildup and draw down intervals.  Semi-log and log-log coordinates have been used to plot the pressure signature date of both buildup period and its derivative to improve diagnostic and Horner plot. In addition, a dual porosity reservoir and infinite acting characteristic was discovered as a result of the well test data interpretation. Wellbore storage, skin factor and transient flow effects have been detected in the DST analysis on the dual porosity behavior due to phase re distribution.  Using final buildup sections, the flow parameters of dual porosity reservoir were determined as the flow between fissure and matrix was (7.558 x 10-6) while, the storability ratio between fissure and matrix was calculated as 0.3 and permeability is 102 MD for both matrix and the fissure together. However, negative value of skin factor mostly appears in double porosity limestone reservoirs, positive skin factor of the reservoir has been observed in this study. It can be considered that the positive skin factor can be resulted in either the formation was partially penetrated and /or wells were not cleaned up properly.

Investigation of Back Pressure Effects on Transient Gas Flow Through Porous Media via Laboratory Experiments and Numerical Simulation

2014 ◽  
Author(s):  
Xiaolei Liu ◽  
Akkharachai Limpasurat ◽  
Gioia Falcone ◽  
Catalin Teodoriu
Keyword(s):  
Steady State ◽  
Gas Flow ◽  
Laboratory Experiments ◽  
Transient Flow ◽  
Pressure Profile ◽  
Back Pressure ◽  
Pressure Effects ◽  
Gas Wells ◽  
Liquid Loading ◽  
Final Steady State

When developing a transient numerical reservoir simulator, it is important to consider the back pressure effects that waves propagating from one end of the porous medium will have on the temporal distribution of pore fluid pressure within the medium itself. Such waves can be triggered by changing boundary conditions at the interface between reservoir and wellbore. An example is given by the transient reservoir response following pressure fluctuations at the wellbore boundary for gas wells suffering from liquid loading. Laboratory experiments were performed using a modified Hassler cell to mimic the effect of varying downhole pressure on gas flow in the near-wellbore region of a reservoir. Gauges were attached along a sandstone core to monitor the pressure profile. The results of the experiments are shown in this paper. A numerical code for modelling transient flow in the near-wellbore region was run to mimic the experiments. The comparisons of simulations and laboratory test results are presented here, for the initial and final steady-state flowing conditions, and where the inlet pressure was maintained constant while initiating a transient pressure build up at the core outlet. The concept of the U-shaped pressure profile along the near-wellbore region of a reservoir under transient flow conditions, originally proposed by Zhang et al. [1], was experimentally and numerically reproduced for single-phase gas flow. This is due to a combination of inertia and compressibility effects, leading to the reservoir response not being instantaneous. The results suggest that, in two phase gas-liquid conditions, liquid re-injection could occur during liquid loading in gas wells. From the experimental results, the U-shaped curves were more obvious and of longer duration in the case of greater outlet pressure. The transition from the initial to the final steady state condition occurred rapidly in all the cases shown here, with the U-shaped pressure profile appearing only over a relatively short time (at the small scale and low pressures tested in this study).

Formation-Tester Pulse Testing in Tight Formations (Shales and Heavy Oil): Where Wellbore Storage Effects Favor the Determination of Reservoir Pressure

2012 ◽  
Author(s):  
Nishaboori Abdolhamid Hadibeik ◽  
Mark A. Proett ◽  
Dingding Chen ◽  
Abbas Sami Sami Eyuboglu ◽  
Carlos Torres-Verdin ◽  
...  
Keyword(s):  
Heavy Oil ◽  
Reservoir Pressure ◽  
Wellbore Storage ◽  
Pulse Testing ◽  
Storage Effects ◽  
Tight Formations

The Need to Understand the Dynamic Interaction Between Wellbore and Reservoir in Liquid Loaded Gas Wells

2008 ◽  
Author(s):  
Fouad A. Solomon ◽  
Gioia Falcone ◽  
Catalin Teodoriu
Keyword(s):  
Oil And Gas ◽  
Transient Flow ◽  
Oil And Gas Industry ◽  
Dynamic Interaction ◽  
Back Pressure ◽  
Pressure Effects ◽  
Gas Wells ◽  
Liquid Loading ◽  
Dynamic Interactions ◽  
Model Liquid

Liquid loading in gas wells is a phenomenon where the liquid content of the well is sufficient to create a back pressure (usually dominated by gravitational pressure changes) which restricts, and in some cases even stops, the flow of gas from the reservoir. Liquid loading is an all too common problem in mature gas fields around the world. It is estimated that in the U.S.A. alone, at least 90% of the producing gas wells are operating in liquid loading regime. The phenomenon is more detrimental in tight wells than in prolific wells and it poses a serious problem in subsea tie-backs, where back pressure effects through the risers and the flowlines may have an important role. Such is the importance of liquid loading; the oil and gas industry has devoted a lot of attention to the alleviation of the problem using various measures. However, the fundamental understanding of the associated phenomena is still surprisingly weak. This applies not only to the flows in the wells, but also to how these flows interact with those in the reservoir. It is this latter dynamic interaction that has received the least attention by the industry. Reliable predictive models to link the well dynamics with the intermittent response of a reservoir, that is typical of liquid loading in gas wells, remain unavailable. This paper introduces the complexity of liquid loading and critically reviews recent attempts to model liquid loading and the dynamic interactions between reservoir and wellbore. The paper then illustrates the need for a better understanding of the transient flow phenomena taking place in the near-wellbore region of the reservoir. This includes re-injection of the heavier phase, a phenomenon that has yet to be proven by fluid mechanics.

Wellbore Storage and Skin Effects During the Transient Flow of Non-Newtonian Power-Law Fluids in Porous Media

1980 ◽  
Vol 20 (01) ◽  
pp. 25-38 ◽  
Author(s):  
Chi U. Ikoku ◽  
Henry J. Ramey
Keyword(s):  
Porous Media ◽  
Power Law ◽  
Transient Flow ◽  
Constant Pressure ◽  
Outer Boundary ◽  
Petroleum Reservoirs ◽  
Storage Effect ◽  
Well Test ◽  
Wellbore Storage ◽  
Power Law Fluids

Abstract A model recently presented by Ikoku and Ramey for non-Newtonian power-law flow in porous media was extended to flow in finite circular reservoirs. A constant flow rate was stipulated at the wellbore, and two boundary conditions were considered: no-flow outer boundary and constant-pressure outer boundary. The results were used to derive a new expression for the stabilization time for power-law flow in porous media.Wellbore storage and skin effects always distort the transient pressure behavior of wells in petroleum reservoirs. It is important to investigate the consequences of these phenomena and be able to interpret real well test information. This paper considers the effects of skin and wellbore storage on the transient flow of non-Newtonian power-law fluids in petroleum reservoirs. petroleum reservoirs. A new numerical wellbore storage simulator was used to study the effects of skin and wellbore storage during the transient flow of power-law fluids in infinitely large and finite circular reservoirs. Results are presented both in tabular form and as log-log graphs of dimensionless pressures vs dimensionless times. The log-log graphs may be used in a type-Curve matching procedure to analyze short-time well test data.The early period is dominated by wellbore storage effect. A new expression was obtained for the duration of wellbore storage effect when skin exists for infinitely large reservoirs. This criterion is not valid for finite circular reservoirs with no-flow outer boundary or constant-pressure outer boundary. Results indicate that there is no apparent end of wellbore storage effect for the no-flow outer boundary condition for the values of external radius presented. New relationships were derived for skin presented. New relationships were derived for skin factor and "effective well radius" for power-law flow. Introduction Many papers in the petroleum engineering, chemical engineering, and rheology literature have addressed the subject of non-Newtonian flow in porous media. These studies have represented non-Newtonian flow with power-law models. Most of the results are similar. The main differences in the final expressions lie in the type of power-law model used.In the basic papers on the transient flow of non-Newtonian power-law fluids in porous media, wellbore storage effect was not considered. Ikoku and Ramey and Odeh and Yang presented techniques for calculating the skin factor from injection well test data. However, wellbore storage and skin effects always distort the transient pressure behavior of wells in petroleum reservoirs. It is important to investigate the consequences of these phenomena to be able to interpret real well test information properly.The flow geometries of interest to petroleum engineers in well test analysis usually involve bounded reservoirs. In most cases, a constant flow rate is stipulated at the well along with one of these outer boundary conditions: no flow across the outer boundary, or constant pressure at the outer boundary. Reservoirs with rectangular and other polygonal shapes often are encountered. Transient polygonal shapes often are encountered. Transient pressure behavior for these shapes may be obtained pressure behavior for these shapes may be obtained by applying the principle of superposition in space to the solutions of the infinitely large reservoir cases.In this paper we seek solutions for constant-rate injection into finite circular reservoirs with no-flow and constant-pressure outer boundaries. SPEJ P. 25

Sign in / Sign up

Export Citation Format

Share Document