Petrophysics
Petrophysics
New in our Free Downloads section is an EXCEL Spreadsheet with Visual Basic macros for generating Relative Permeability curves. The macros use estimates of irreducible and residual saturation along with wettability-related parameters. The Spreadsheet contains suggestions from the literature for appropriate parameters.
Don Henderson has more than 30 years of formation evaluation experience in Australia, South-East Asia, Venezuela, US Gulf Coast, North Africa, the Indian sub-continent and the Middle East.
Henderson Petrophysics offers highly specialised formation evaluation services to the oil and gas exploration and development industry.
We offer data analysis and report preparation services at the wellsite, in your office, or in our office.
In the Special Features section (Menu to the left) you can read how "Virtual Petrophysics" may be a very cost effective real-time solution for your data analysis needs.
The Special Features article "Add Value with Petrophysics" is devoted to case studies showing how petrophysics can add value to your oil and gas portfolio.
We are based in the beautiful sub-tropical city of Brisbane in the Australian state of Queensland. We offer specialised formation evaluation services to the upstream oil and gas businesss.
For more information on our services or our fee schedule you can send us an e-mail (click on the icon below) or contact us using the following information;
Phone: +61 7 3300 3980 (61 is the country code for Australia and 7 is the area code for Brisbane)
Mobile: +61 407 653342
Skype: User ID donhenderson4061 or search using email address
E-mail: don@hendersonpetrophysics.com
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Don Henderson is very experienced with providing "Quicklook" log interpretation of data from exploration, appraisal and development wells. We can do the interpretation in your office or at the wellsite. Alternatively, you can send us the data by e-mail for real-time evaluation.
The Special Features article "Virtual Petrophysics" discusses how Web-based technology can provide very cost effective formation evaluation solutions.
With our long experience we can ensure that all of the potential reservoirs in your wells are adequately evaluated.
We can advice you on how to efficiently spend your formation evaluation budget and not waste money on inappropriate operations.
With very difficult hole conditions it may not be possible to acquire all of the data in your logging program. We have faced this situation many times, and we can help you to decide on appropriate operations procedures to ensure that you get the best possible data while minimising the risk of losing the hole.
Supervising logging operations leaves little time for a complete wellsite log interpretation. In these situations, we ensure that all the necessary data is collected, that it is of the highest possible quality, and that you are kept fully informed of the available formation evaluation options.
Don Henderson has many years of wellsite geology experience. Starting in 1972 he worked as a Mudlogger in Australia, Venezuela and South East Asia. After joining Esso Australia in 1978 Don worked in the Geological Operations group. Assignments included sitting offshore, frontier exploration wells in Australia and field development wells offshore Australia and in South East Asia.
Later assignments in the Esso Production Geology and Petrophysics groups gave further wide exposure to wellsite operations, mainly in deviated, offshore appraisal and development wells.
Naturally, all of the the wellsite experience involved supervision of mudlogging, coring and wireline logging operations.
Don also has many years of experience in the efficient preparation of well reports for distribution to government departments and joint venture partners.
Don Henderson has extensive experience conducting petrophysics field studies. These studies almost always involve:
- Gathering data and building a Petrophysics data base,
- Data editing and normalisation,
- Developing specialized log analysis algorithms and models,
- Detailed, comprehensive computer log interpretation,
- Integration of available core data (descriptions and analysis results),
- Interpretation and integration of reservoir pressure data.
We can develop specialized log analysis models to evaluate your difficult and unusual formation evaluation problems.
The Special Features section (menu on the left) contains an example outline for a Petrophysics field study.
Don Henderson is highly skilled in the art of developing innovative petrophysical models to solve difficult formation evaluation problems. Many years of experience has taught Don that every well has a unique data set that requires a specialised approach for appropriate formation evaluation.
Don has developed highly innovative methods to evaluate a wide variety of reservoirs including;
Low resistivity / low contrast (LRLC) reservoirs,
Laminated to thinly bedded reservoirs, and,
Tight and fractured reservoirs.Other applications where specialised analysis models have been developed are;
Artificial sonic logs from resistivity using the Faust equation,
Models to "clean-up" sonic logs for improved synthetics,
Programs to "block" wireline logs curves to remove bed boundary effects,
Programs to resolution match wireline logs,
Basin screening studies to identify bypassed pay using "old" logs or minimal logging suites
Programs to identify hydrocarbon source rocks and determine organic matter content (TOC).
Henderson Petrophysics specializes in analysis of petrophysical data for prospect development and for the evaluation of investment opportunities.
We have a lot of experience in data rooms where a small team of experts has very little time to perform an economic evaluation of an upstream investment opportunity. It takes a great deal of experience for a Petrophysicist to be able quickly synthesise data that is relevant for determining an economic value for an oil or gas investment opportunity.
Fractured and tight reservoirs require very careful petrophysical analysis in order to avoid serious overestimation of reserves.
Flow rates from fractured reservoirs are often very high. This is sometimes intepreted as indicating large reserves but the truth is that fracture porosity is almost always extremely low and that reserves are very, very difficult to determine.
Conventional log analysis is just about impossible in fractured reservoirs. Tight reservoirs are often associated with washed-out and rugose borehole. Apparent porosity from pad type logging tools such as density, shallow resistivity and NMR is usually too high (and often useless or misleading). Even sonic tools read too high because of signal attenuation and associated waveform "stretch".
It is usually very difficult to accurately determine hydrocarbon saturation in low porosity reservoirs because small errors in porosity determination result in large changes to calculated Sh.
We probably cannot give you quick and definitive analysis results for determining reserves in your tight and/or fractured reservoirs. However, we can very quickly examine your data and determine if the results you have are reasonable. We can then recommend methods to reduce uncertainty in your reserves estimates.
The Special Features article "Fractured Basement Model" discusses the effects of extreme reservoir heterogeneity on logging tools and the resulting formation evaluation implications.
The Special Features article "Working with Sonic Logs" discusses some of the borehole conditions that can result in unreliable sonic logs.
We have a great deal of experience evaluating low resistivty and low resistivity contrast (LRLC) reservoirs.
Low resistivity contrast reservoirs are almost always pessimistically evaluated. Standard log analysis methods that have been used for many years and that are generally widely accepted are guaranteed to result in a very pessimistic estimate of net pay, reservoir quality and reserves.
If you are producing from LRLC reservoirs, why not contact us for an independent audit of the petrophysical parameters and methods used to calculate your reserves.
If you are negotiating to buy equity in projects with LRLC reservoirs, contact us for an independent audit of the vendor's reserves estimates.
If you are exploring for LRLC reservoirs, we can advice you on appropriate logging programs/procedures and formation evaluation techniques.
We use modifications to the Exxon method (Passey et. al. 1990) to identify source rock intervals and to determine organic carbon content. The Exxon method creates baseline conditions for resistivity and porosity (usually sonic) log curves. Organic matter content is calculated as a function of the separation of these baselined curves and organic maturity.
The Exxon method is only designed for use in shales. Don Henderson has modified the technique to create baseline conditions through the full range of clean reservoirs to shale. This modification allows both identification of source rocks and hydrocarbons reservoirs. The Henderson modification of the Exxon method also allows calculation of hydrocarbon saturation using only a minimal logging suite and does not require explicit porosity or water salinity information.
The Special Features article "Source Rock From Logs" contains a detailed discussion of the log analysis model used by Henderson Petrophysics to calculate TOC.
The Special Features article "Overlay Water Saturation Model" discusses the theory for the model to calculate Sw with minimal parameter information.
Core data is usually considered to be "ground truth" in petrophysics. We have many years of experience integrating core and log data to create innovative petrophysical solutions.
We always incorporate core descriptions and analysis data into our specialised log analysis models
We offer expert help in planning your wireline logging operations. We will help you to select appropriate, efficient and cost-effective combinations of logging tools for your unique requirements.
Since Logging contractors are in business to maximise profit, you cannot always rely on them for advice on appropriate, and cost effective, logging programs. Don Henderson has lots of experience negotiating with logging contractors and can help to ensure that you get the services that are appropriate to your needs and that can be achieved if you have difficult or ususual hole conditions.
Don Henderson has many years of wellsite operations experience including the supervision of logging jobs. If necessary we can be on-site to supervise your vital logging jobs. At your request, we will oversee wireline log data quality control on important wells, either at the wellsite or remotely (using digital links).
In the Special Features section (Menu to the left) you can read how "Virtual Petrophysics" may be an appropriate formation evaluation option for your company.
In the Free Downloads section you will find the self-extracting Zip file "WirelineQC". This file contains examples of wireline log quality control and time breakdown forms. You are welcome to download this file and to use or modify the forms.
Core data is crucial in describing your reservoirs. We can help you plan your routine and special core analysis program.
We have a lot of experience working with core analysis laboratories to ensure that appropriate procedures are followed and that reports are adequately documented.
Don Henderson has many years of experience in estimating in-place hydrocarbon reserves using both stocastic and deterministic methods.
Don's expertise in evaluating the petrophysical properties of reservoirs is invaluable since these parameters are crucial for volumetric calculations. Our experience ranges from estimating the expected volumes to be accessed by field development and the reserves changes resulting from drilling of exploration appraisal wells.
We can help you to build and maintain a prospects and leads database. For each prospect identified by your Geophysicists we can estimate expected hydrocarbon reserves.
The Free Downloads section (Menu on the left of the screen) contains two EXCEL programs that you can download and use to estimate in-place and recoverable hydrocarbon reserves.
We can give you help and advice with;
- Preparation of wireline logging and mud logging pre-qualification tender documents
- Technical and financial evaluation of tender documents from formation evaluation contractors
- Cost-benefit analysis of Vendor suggestions for additions or changes to base contracts
- Re-negotiation of formation evaluation contracts (wireline logging, mud logging and core analysis)
A very large part of the work involved in analyzing petrophysical data is work required to create and maintain a database. Don Henderson has many years of experience in creating and maintaining databases.
We can help you create or update your petrophysical database for field studies and reservoir modeling. Some of the tasks required for database maintenace are;
- Log digitising. We do not do this but can organise and quality control sub-contractors
- Log curve splicing,
- Baselining. For example removing the shift and drift of SP curves,
- Log normalisation to overcome the effects of faulty calibration,
We often deal with "old" or very poor quality logs that need to be digitised and normalised.
We use both well established and proprietory techniques to "fill in the blanks" where data is either missing of of poor quality. For example, in a recent exploration project we used innovative mentods to create artifical sonic and density logs where the data was missing or not usable because of very poor hole conditions. This "clean" data was used to create synthetics with an excellent "tie" to the 3d seismic data.
We can provide expert advice on log normalization.
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