RESERVOIR CHARACTERISATION OF A LOW RESISTIVITY GAS FIELD-OTWAY BASIN, SOUTH AUSTRALIA

1996 ◽  
Vol 36 (1) ◽  
pp. 62 ◽  
Author(s):  
T. Scholefield ◽  
C.P. North ◽  
H.L. Parvar
Keyword(s):  
Water Saturation ◽  
Material Balance ◽  
South Australia ◽  
Production Test ◽  
Well Performance ◽  
Gas Field ◽  
Evaluation Procedures ◽  
Comprehensive Picture ◽  
Reservoir Porosity ◽  
Facies Modelling

The Katnook, Haselgrove and Ladbroke Grove Fields of southeastern SA are characterised by a lack of resistivity contrast above and below known gas-water contacts, poor hole conditions, complex mineralogy and fresh formation water. A multi-disciplinary review of all available data to characterise the Pretty Hill Sandstone reservoir by integrating core, log and engineering data has enabled a comprehensive picture of reservoir heterogeneity and its influence on log response and well performance to be determined. The availability of extensive core throughout the 6 wells has resulted in the accurate modelling of reservoir porosity and the derivation of a facies-dependent, quantitative permeability log which closely matches drill stem test and production test derived permeability thickness (kh). Previous water saturation assumptions have been shown to be optimistic with Leverett J Function water saturation averaging 50-60 per cent through the reservoir. Detailed facies modelling from the cores extrapolated into areas with no core control has led to the derivation of a geological model which, when integrated into a 3D simulation, has resulted in calculated pressures within 1 per cent of those measured and has enabled the prediction of the pressure response from highly compartmentalised portions of the reservoir. Simulation-derived, material balance and volumetric original-gas-iti-place for the Katnook Field now agree to within 5 per cent.The study has resulted in changes to previously accepted evaluation procedures for wells targeting the Pretty Hill Sandstone.

Material Balance for a Bottom-Water-Drive Gas Reservoir

1973 ◽  
Vol 13 (06) ◽  
pp. 328-334
Author(s):  
J.M. Dumore
Keyword(s):  
Water Saturation ◽  
Material Balance ◽  
Gas Reservoir ◽  
Gas Field ◽  
Water Contact ◽  
Free Gas ◽  
Water Influx ◽  
Cumulative Production ◽  
Gas Volume ◽  
Limiting Value

Abstract A material balance is developed for a gas reservoir in which the rising gas/water contact remains horizontal. The time-integrated cumulative water influx is introduced, which for numerical computations is sometimes more advantageous than the van Everdingen and Hurst integral. On the basis of the equations developed, material balance calculations of the history of an actual gas field are carried out to calculate the water influx. The strength of the estimated radial, limited aquifer, which must supply the water for the influx, is determined. It appears that the strength decreases with time and asymptotically approaches a limiting value. (Some possible reasons for this decrease are mentioned.) If we take the strength as constant and equal to the limiting value, however, very small deviations from the past pressures occur. With the same value for the strength of the aquifer, the future behavior of the gas reservoir is computed, assuming constant gas production rate and no water production. Introduction For a depletion-type gas reservoir - i.e., when there is no water encroachment - the average gas pressure is a function of the cumulative production pressure is a function of the cumulative production and can easily be calculated from a material balance. For a gas reservoir bounded by an aquifer, the average gas pressure also depends on the water influx, which in turn depends on the rate of pressure decline and thus on the production rate. In this case the material balance is much more complicated. In the following we have developed the material balance of a bottom-water-drive gas reservoir, in which the rising gas/water contact remains horizontal. In a numerical example, the equations are applied to an actual gas field in Northwest Germany. THE GAS RESERVOIR Let us consider a gas reservoir bounded by a horizontal gas/water contact. The bulk area of a horizontal cross-section through the reservoir at a height b above the original gas/water contact is denoted by A(h), and the part of this area taken up by free gas is denoted by F(h). in which and Swc are the average values of porosity and connate water saturation at level h. porosity and connate water saturation at level h. Function F(h) can also be considered as the free gas volume in the reservoir at level h per unit height. Consequently, the free gas volume in the reservoir between the original gas/water contact h = 0 and a certain level h = h' is 0 The total original free gas volume in the reservoir is in which H is the height of the top of the gas-bearing formation above the original gas/water contact; i.e., the closure of the reservoir. The original volume of free gas in place, measured at standard conditions, is where the reciprocal gas formation volume factor is defined by Since in general we may take the average reservoir temperature for Tres, 1/Bg is a function of pressure only. A fair approximation of Eq. 4 is obtained by taking (1/Bg)i independently of h and equal to the value corresponding to the average initial reservoir pressure. Then pressure. Then SPEJ P. 328

Flowing Material Balance Analysis and Production Optimization in HPHT Sour Gas Field

2019 ◽  
Author(s):  
Azis Hidayat ◽  
Dwi Hudya Febrianto ◽  
Elisa Wijayanti ◽  
Diniko Nurhajj ◽  
Ahmad Sujai ◽  
...  
Keyword(s):  
Material Balance ◽  
Production Optimization ◽  
Gas Field ◽  
Balance Analysis ◽  
Flowing Material ◽  
Sour Gas

A Dynamic Workflow of Well Health Issue Prediction – Sulfur Deposition

2021 ◽  
Author(s):  
Bashirul Haq
Keyword(s):  
Material Balance ◽  
Gas Production ◽  
Health Issue ◽  
Sulfur Deposition ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Actual Performance ◽  
Sulphur Deposition ◽  
Balance Analysis ◽  
Sour Gas

Abstract Sour gas reservoirs are vital sources for natural gas production. Sulphur deposition in the reservoir reduces a considerable amount of gas production due to permeability reduction. Consequently, well health monitoring and early prediction of Sulphur deposition are crucial for effective gas production from a sour gas reservoir. Dynamic gas material balance analysis is a useful technique in calculating gas initially in place utilizing the flowing wellhead or bottom hole pressures and rates during the well's lifetime. The approach did not apply to monitor a producing gas's health well and detect Sulphur deposition. This work aims to (i) modify dynamic gas material balance equation by adding the Sulphur deposition term, (ii) build a model to predict and validate the issue utilizing the modified equation. A unique form of the flowing material balance is developed by including Sulphur residue term. The curve fitting tool and modified flowing gas material balance are applied to predict well-expected behaviour. The variation between expected and actual performance indicates the health issue of a well. Initial, individual components of the model are tested. Then the model is validated with the known values. The workflow is applied to active gas field and correctly detected the health issue. The novel workflow can accurately predict Sulphur evidence. Besides,the workflow can notify the production engineers to take corrective measures about the subject. Keywords: Sulfur deposition, Dynamic gas material balance analysis, Workflow

scholarly journals Reservoir Performance Prediction using Integrated Production Modelling (MBAL Software)

2019 ◽  
Vol 8 (4) ◽  
pp. 1484-1489
Keyword(s):  
Performance Prediction ◽  
History Matching ◽  
Material Balance ◽  
Development Planning ◽  
Reservoir Rock ◽  
Rock Properties ◽  
Production Operation ◽  
Gas Field ◽  
Reservoir Performance ◽  
Fluid Properties

Reservoir performance prediction is important aspect of the oil & gas field development planning and reserves estimation which depicts the behavior of the reservoir in the future. Reservoir production success is dependent on precise illustration of reservoir rock properties, reservoir fluid properties, rock-fluid properties and reservoir flow performance. Petroleum engineers must have sound knowledge of the reservoir attributes, production operation optimization and more significant, to develop an analytical model that will adequately describe the physical processes which take place in the reservoir. Reservoir performance prediction based on material balance equation which is described by Several Authors such as Muskat, Craft and Hawkins, Tarner’s, Havlena & odeh, Tracy’s and Schilthuis. This paper compares estimation of reserve using dynamic simulation in MBAL software and predictive material balance method after history matching of both of this model. Results from this paper shows functionality of MBAL in terms of history matching and performance prediction. This paper objective is to set up the basic reservoir model, various models and algorithms for each technique are presented and validated with the case studies. Field data collected related to PVT analysis, Production and well data for quality check based on determining inconsistencies between data and physical reality with the help of correlations. Further this paper shows history matching to match original oil in place and aquifer size. In the end conclusion obtained from different plots between various parameters reflect the result in history match data, simulation result and Future performance of the reservoir system and observation of these results represent similar simulation and future prediction plots result.

Reserves Determination Using Type Curve Matching and Extended Material Balance Methods in the Medicine Hat Shallow Gas Field

1994 ◽  
Author(s):  
S. L. West ◽  
P. J. R. Cochrane
Keyword(s):  
Material Balance ◽  
Poor Quality ◽  
Curve Matching ◽  
Pressure Data ◽  
Gas Reservoirs ◽  
Shallow Gas ◽  
Gas Field ◽  
Type Curve ◽  
Balance Analysis ◽  
Diffusivity Equation

Tight shallow gas reservoirs in the Western Canada Basin present a number of unique challenges in accurately determining reserves. Traditional methods such as decline analysis and material balance are inaccurate due to the formations' low permeabilities and poor pressure data. The low permeabilities cause long transient periods not easily separable from production decline using conventional decline analysis. The result is lower confidence in selecting the appropriate decline characteristics (exponential or harmonic) which significantly impacts recovery factors and remaining reserves. Limited, poor quality pressure data and commingled production from the three producing zones results in non representative pressure data and hence inaccurate material balance analysis. This paper presents the merit of two new methods of reserve evaluation which address the problems described above for tight shallow gas in the Medicine Hat field. The first method applies type curve matching which combines the analytical pressure solutions of the diffusivity equation (transient) with the empirical decline equation. The second method is an extended material balance which incorporates the gas deliverability theory to allow the selection of appropriate p/z derivatives without relying on pressure data. Excellent results were obtained by applying these two methodologies to ten properties which gather gas from 2300 wells. The two independent techniques resulted in similar production forecasts and reserves, confirming their validity. They proved to be valuable, practical tools in overcoming the various challenges of tight shallow gas and in improving the accuracy in gas reserves determination in the Medicine Hat field.

scholarly journals Formation evaluation and reservoir characteristics of the Messinian Abu Madi sandstones in Faraskour Gas Field, onshore Nile Delta, Egypt

2020 ◽  
Author(s):  
Mahmoud Leila ◽  
Ali Eslam ◽  
Asmaa Abu El-Magd ◽  
Lobna Alwaan ◽  
Ahmed Elgendy
Keyword(s):  
Water Saturation ◽  
Nile Delta ◽  
Hydrocarbon Exploration ◽  
The Other ◽  
Reservoir Rock ◽  
Reservoir Quality ◽  
Pore System ◽  
Reservoir Properties ◽  
Gas Field ◽  
Irreducible Water Saturation

Abstract The Messinian Abu Madi Formation represents the most prospective reservoir target in the Nile Delta. Hydrocarbon exploration endeavors in Nile Delta over the last few decades highlighted some uncertainties related to the predictability and distribution of the Abu Madi best reservoir quality facies. Therefore, this study aims at delineating the factors controlling the petrophysical heterogeneity of the Abu Madi reservoir facies in Faraskour Field, northeastern onshore part of the Nile Delta. This work provides the very first investigation on the reservoir properties of Abu Madi succession outside the main canyon system. In the study area, Abu Madi reservoir is subdivided into two sandstone units (lower fluvial and upper estuarine). Compositionally, quartzose sandstones (quartz > 65%) are more common in the fluvial unit, whereas the estuarine sandstones are often argillaceous (clays > 15%) and glauconitic (glauconite > 10%). The sandstones were classified into four reservoir rock types (RRTI, RRTII, RRTIII, and RRTIV) having different petrophysical characteristics and fluid flow properties. RRTI hosts the quartzose sandstones characterized by mega pore spaces (R35 > 45 µm) and a very well-connected, isotropic pore system. On the other side, RRTIV constitutes the lowest reservoir quality argillaceous sandstones containing meso- and micro-sized pores (R35 > 5 µm) and a pore system dominated by dead ends. Irreducible water saturation increases steadily from RRTI (Swir ~ 5%) to RRTIV (Swir > 20%). Additionally, the gas–water two-phase co-flowing characteristics decrease significantly from RRTI to RRTIV facies. The gaseous hydrocarbons will be able to flow in RRTI facies even at water saturation values exceeding 90%. On the other side, the gas will not be able to displace water in RRTIV sandstones even at water saturation values as low as 40%. Similarly, the influence of confining pressure on porosity and permeability destruction significantly increases from RRTI to RRTIV. Accordingly, RRTI facies are the best reservoir targets and have high potentiality for primary porosity preservation.

PETROPHYSICS OF THE COOPER BASIN, SOUTH AUSTRALIA

1972 ◽  
Vol 12 (1) ◽  
pp. 23
Author(s):  
Chris R. Porter ◽  
Hugh Crocker
Keyword(s):  
Water Saturation ◽  
South Australia ◽  
Clay Content ◽  
Computer Applications ◽  
Test Results ◽  
Upper Limits ◽  
Porosity And Permeability ◽  
Log Interpretation ◽  
Logging Tool ◽  
Cooper Basin

In the Cooper Basin lithologic types can be recognised and related to logging tool response. Empirical relationships between log readings and porosity and permeability can be developed locally by comparing log readings with core data. Water saturation/porosity relationships are found to be convergently hyperbolic. The effects of clay minerals upon water saturation determination show that only in the low porosity range is correction for clay necessary.A plot of Sw versus Sxo allows prediction of probable test results and has been confirmed by actual Cooper Basin well tests.An attempt to relate clay content to permeability has been successful in estimating tentative upper limits of permeability. Computer applications to log interpretation are utilized in achieving petrophysical parameters.

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