Petroleum Goodies

Monday, June 10, 2013

Petroleum Goodies: Rate-Time Spreadsheet

Posted: 09 Jun 2013 08:12 PM PDT

Rate-Time Spreadsheet (RTS) To Estimate Range of Your Reserves

This Excel spreadsheet helps you to calculate range of production forecast using seven different methods by analyzing gas or oil production (i.e. rate-time) data.

This tool is available for Excel 2003 and 2007 versions. For those who use newer version of Excel (2013 and later versions) can use the 2007 version. The authors of this tool provide user guide on how use this tool (see download links at the bottom of this page). They also provide examples using tight gas well. For more details, please read SPE papers 116731, 119897, 132352 from OnePetro website.

Using The Rate-Time Spreadsheet

Edit Data Sheet

The authors built the RTS based on order when you want to analyze your data. It starts by entering your rate-time data (or cumulative production – optional) into sheet Edit Data. In this sheet, you can exclude unwanted data points by entering 0 (zero number) in column D. Once you finish editing unwanted data points, then go to sheet Home.

Home Sheet

In this sheet, you can calculate Loss Ratio (D) and Loss Ratio Derivative (b) by clicking on the Calculate buttons. This tool provides two different methods to calculate D parameter; using production rate and cumulative production.

Rate-Time Relation Sheets

These sheets allow you to choose rate-time relation that you want to use. The relations include:

Arps’ Exponential (exp) Relation
Reciprocal Rate Method
Arps’ Hyperbolic (hyper) Relation
Modified Hyperbolic (MH) Relation
Power-Law Exponential (PLE) Model
Ansah, Knowles and Buba (AKB) Semi-Analytic Relation
Quadratic Rate Cumulative Relation

Summary & Appendix Sheets

At the end of RTS, you are provided with summary of estimated ultimate recovery (EUR) calculations and decline parameters. The EUR calculation can be limited either by abandonment rate or time. To see the equations to calculate rate-time relations you can go to Appendix sheet.

Improvement

The RTS is an excellent Excel-based tool to analyze rate-time data. This tool can calculate EUR using seven different methods for individual well. If you have more than one well to analyze, you can make a copy of this tool and change your rate-time data. You can improve this tool by allowing rate-time inputs from multiple wells. VBA programming skill might required to do this improvement.

If you have questions or inquires related to the RTS, you can contact one of the authors of this tool at stephaniemariecurrie[at]gmail.com.

Using VBA macro? Yes

Download The Rate-Time Spreadsheet

Note: There is a file embedded within this post, please visit this post to download the file.

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Sunday, February 10, 2013

Petroleum Goodies: Calculate Gas Properties

Calculate Gas Properties

Posted: 09 Feb 2013 07:21 PM PST

Web-based & Excel Tools To Calculate Dry Gas Properties

It is essential for Petroleum Engineers to make various calculations in order to arrive at certain important figures on dry gas properties when they are engaged in working on their projects. Since these are quite time consuming calculations the presence of a web-based tool that does the calculations when their input figures are entered is of immense benefit for them. What you get in Excel format in this webpage is exactly that. It is a tool that could help them calculate various figures they need. When it comes to dry gas properties you may need inputs such as gas gravity, mole percent of CO₂ and H₂S, bottom hole pressure and temperature.

In addition to the final calculations they may also need to make intermediate calculations to obtain such figures as pseudocritical pressure and temperature, reduced pressure and temperature. With these calculations they may arrive at such figures as gas compressibility factor (Z), gas viscosity, gas formation volume factor (Bg), gas compressibility (Cg) and gas pseudo pressure (Pp). The tool available in the form of an Excel sheet is able to help Petroleum Engineers to do all these calculations effortlessly.

Various methods have been used in the calculation of dry gas properties. When it comes to the calculation of pseudocritical variables they were based on Sutton equation. For the calculation of gas compressibility factor Dranchuk and Abou-Kassem equation was used. In case of gas viscosity equation it is the Lee, Gonzales and Eakin equation that is being used.

The possibility is there for you to change labels of charts. Also, you could go to chart options and manually adjust the scales of charts. The calculated table available with the tool could be copied on to clipboard or could be exported to Excel or CSV files. When you choose print screen option you could print the charts also if you want.

Link to web-based tool to Calculate Dry Gas Properties.

Download Excel version

Note: There is a file embedded within this post, please visit this post to download the file.Related Posts:

Monday, January 14, 2013

Petroleum Goodies: Gas Compressibility Factor

Gas Compressibility Factor

Posted: 13 Jan 2013 09:13 PM PST

Web Tool To Calculate Gas Compressibility Factor

We rewrite VBA Excel function to calculate gas compressibility factor (Z) using JavaScript and develop a web tool so Petroleum Goodies users can Z factor directly from our website.

This web tool calculates gas compressibility factor for natural gases based on equation of state from Dranchuk and Abou-Kassem. Required inputs: gas gravity (air=1), mole percent of CO₂ and H₂S, pressure and temperature.

This tool also includes intermediate calculation such as pseudocritical pressure and temperature.

References:

Dranchuk, P.M., and Abou-Kassem, J.H.: “Calculation of Z Factors For Natural Gases Using Equations of State,” J. Cdn. Pet. Tech. (July-Sept., 1975) 34-36.
“Theory and Practice of Testing Gas Wells”, 3rd. Edition (1975) Energy Resources Conservation Board 603 6th. Ave. S.W. Calgary, Alberta, Canada.

Link to Web Tool To Compute Gas Compressibility Factor.

This web tool is also available for download in Excel version.

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