A comprehensive method for determining net pay in exploration/development wells

Qassamipour, Mehdi; Khodapanah, Elnaz; Tabatabaei‐Nezhad, Seyyed Alireza

doi:10.1016/j.petrol.2020.107849

Cited by 4 publications

(3 citation statements)

References 16 publications

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“…Compared with conventional reservoirs, the development of tight reservoirs faces greater difficulties and challenges; the research methods applied in conventional reservoirs cannot meet the production requirements in tight reservoirs, and the poor evaluation of parameters during the exploration period can have various effects on later production [9]. Among them, the identification of reservoir effectiveness as a key task in the identification of fluid property, reserve calculation, and the formulation of development plans [10][11][12][13][14] has always been a research hotspot and a major problem for scholars in related fields internationally, especially for complex reservoirs such as tight gas reservoirs.…”

Section: Introductionmentioning

confidence: 99%

“…However, in order to obtain an accurate lower limit of the physical properties, it is necessary to attain accurate oil saturation and sufficient well test data [11]. Mehdi Qassamipour et al divided effective reservoirs by establishing oil and gas rate profiles to determine oil and gas production limits [10]. However, this method is not suitable for natural gas reservoirs because it is based on Darcy's flow equation.…”

Section: Introductionmentioning

confidence: 99%

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A Method for Judging the Effectiveness of Complex Tight Gas Reservoirs Based on Geophysical Logging Data and Using the L Block of the Ordos Basin as a Case Study

2023

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As an important unconventional oil and gas resource, the tight gas reservoir faces many technical challenges due to its low porosity, low permeability, and strong heterogeneity. Among them, the accurate definition of effective reservoirs and ineffective reservoirs in tight gas reservoirs directly affects the formulation and adjustment of subsequent development plans. This paper proposes a reservoir effectiveness identification method based on double factors based on conventional geophysical logging data and core experimental data. The double factors considered are based on the logging response and physical parameters of the reservoir. The identification factor F1 is obtained by using the difference in the logging response values of the natural gamma logging curve, compensated density logging curve, and acoustic time difference logging curve in different reservoirs combined with mathematical operation, and the identification factor F2 is calculated by using porosity parameters combined with Archie’s formula. The validity of the reservoir can be judged by the intersection of the above double factors. This method is applied to the Shihezi Formation in the L block, and the applicability of the double factors is compared and analyzed using the traditional method. The results show that the method has strong applicability in tight gas reservoirs and that the accuracy rate reaches 96%. Compared with the direct use of the porosity lower limit method, the accuracy of the judgment is significantly improved, and the calculation is simple, easy to implement, and unaffected by mud invasion. For study areas with different geological backgrounds, the process of this method can also be used to determine the effectiveness of the reservoir. The reservoir effectiveness identification method proposed in this paper has practical engineering significance and lays a solid foundation for subsequent fluid property identification, production calculation, and development plan formulation and adjustment.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Method for Judging the Effectiveness of Complex Tight Gas Reservoirs Based on Geophysical Logging Data and Using the L Block of the Ordos Basin as a Case Study

2023

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“…Opuwari et al 2020a, b;Radwan et al 2020). The reservoir zonation approach helps to understand reservoir heterogeneity and identify productive zones within a reservoir, which is subsequently upscale to field-scale reservoir mapping (Opuwari 2010;Qassamipour et al 2021).…”

Section: Introductionmentioning

confidence: 99%

An integrated approach of reservoir characterization of Y gas field in Central Bredasdorp Basin, South Africa

Masindi

(1)²,

Opuwari

2022

J Petrol Explor Prod Technol

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The study attempts to address the knowledge gap in the Bredasdorp Basin Offshore South Africa by using newly acquired seismic data with an enhanced resolution, integrating core and well log to provide a solution. The main objective of this study was a volumetric sandstone reservoir characterization of the 13At1 and 10At1 sandstones deposited in the upper shallow marine environment. The results reveal four facies grouped as facies 1(claystone), facies 2(intercalation of claystone and sandstone, facies 3(medium sandstone), and facies 4 fine-medium sandstone grain deposited in a deep marine environment. Facies 3, the medium-grained sandstone, has the best reservoir quality rock, while facies 1, which is predominantly claystone, has the least rock quality. The study has produced a calculated volume of gas in the 10At1 sand (upper and lower sand is 30.01 billion cubic feet (bcf)) higher than that of the 13At1 sand (27.22 bcf of gas). Improved seismic resolution enhanced the accuracy of results. It is advisable to focus further field development in the eastern part of the Y gas field because of good reservoir quality and production developed due to the sand in the 10At1 sequence.

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A comprehensive methodology for reservoir cut-off determination

Zeyghami

Sarvestani

2023

J Petrol Explor Prod Technol

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The main objective of net pay determination, as an important step of any reservoir study, is to exclude non-reservoir intervals so that better results are obtained from reservoir characterization, hydrocarbon in-place calculations, and dynamic flow simulation of the reservoir. This study is a comprehensive presentation of the most applicable methods available for net pay determination, highlighting their strengths, limitations, and their input data, and presenting a new procedure to prepare the input data, determine the reservoir net pay, and validate the final results. These methods include conventional best-fit line and quadrant methods in a porosity–permeability cross-plot, Worthington method, rules of thumb, cumulative hydrocarbon column plot, and production constraints. This study, unlike previous ones, presents a stepwise methodology to reach the correct answer considering both rock and fluid properties. The necessity for the definition of net pay is discussed in the current study in the first step. Determination of net pay and the net-to-gross ratio is done by definition of some cut-off values for petrophysical properties such as porosity, water saturation, and shale volume. The new procedure presented in this study as a flowchart to determine pay zone uses different methods to determine cut-off values. The sequential and systematic use of all these methods gives a consistent and more reliable answer. The key steps to determine net pay is to find the porosity cut-off based on a porosity–permeability cross-plot and a pre-defined limiting value for permeability and then to use this value to find the shale volume and water saturation cut-offs using their cross-plots versus porosity. To take into account the fluid properties effect, a mobility cut-off is used as the starting point instead of permeability. Cumulative hydrocarbon column plots are used as a sensitivity tool to determine what percentage of the hydrocarbons will be discarded by any cut-off value. Finally, the determined net pay should be validated using the results of production logging and wireline formation tests. The proposed methodology was applied to a real field to determine its net pay. Porosity and water saturation cut-offs were calculated to be 2% and 55%, respectively, and due to the clean nature of the reservoir, a shale volume cut-off was not necessary. Simultaneous application of porosity and water saturation cut-offs discarded 6.3% of the hydrocarbon column for the field example.

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A comprehensive method for determining net pay in exploration/development wells

Cited by 4 publications

References 16 publications

A Method for Judging the Effectiveness of Complex Tight Gas Reservoirs Based on Geophysical Logging Data and Using the L Block of the Ordos Basin as a Case Study

A Method for Judging the Effectiveness of Complex Tight Gas Reservoirs Based on Geophysical Logging Data and Using the L Block of the Ordos Basin as a Case Study

An integrated approach of reservoir characterization of Y gas field in Central Bredasdorp Basin, South Africa

A comprehensive methodology for reservoir cut-off determination

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