Log ASCII Standard File

For Information about the Log ASCII Standard file and to download LAS samples visit the following link:
http://www.minnelusa.com/sampledata.php

Explanation of Modules

This architecture represents the internal working, structure and behavior of the REOG system. It defines the system components or building blocks such as the Map Input, Log Input, Map Processing, Well Log Interpretation, and Reserve Estimation and provides a plan from which these systems will work together to implement the overall system. The user of this system will be a geophysicist or a geologist.

Application User Interface

The user can ask the system three things

• View Reserve Estimation Results
• View Parameter Information
• View High Probability Area

Map Input

This component represents the input in the form of a map that the geophysicist has to provide for the processing to start.

Analog Map

If the user provides the system with the analog map, the system will convert the map into a digital map.

Digital Map

If the user provides the system with a digital map then the system carries out the map processing phase.


Log Input
The well log basically comprises of two parts, the digital log and the Log ASCII Standard (LAS) file format. In order to interpret the well log, REOG system would need both these files.

Digital Log

Digital log contains the values of different reservoir parameters graphically which helps the system to evaluate the amount of hydrocarbon at different depths of the reservoir.

Log ASCII Standard File

LAS file contains different reservoir parameters that are required for the final calculation of amount of oil and gas in place. These reservoir parameters are present in the LAS file for different depths of the reservoir.


Map Processing
This component contains the application of two digital image processing techniques of image gridding and image contouring.

Image Gridding

Grid references define locations on maps using Cartesian coordinates. Grid lines on maps define the coordinate system, and are numbered to provide a unique reference to features. The grid numbers on the east-west (horizontal) axis are called Eastings, and the grid numbers on the north-south (vertical) axis are called Northings.

Image Contouring

After applying different techniques like interpolation and extrapolation, we connect all the points of a grid map and turn the grid lines into contour lines. These lines outline the high probability reservoir area for Oil and Gas accumulation.


Well Log Interpretation

This phase contains two parts of obtaining parameters and cross plotting.

Obtaining Parameters

The well log is interpreted with the help of Log ASCII Standard file and all the reservoir parameters are gathered. The LAS file may contain a few or all of the reservoir parameters that are required for the reserve estimation calculation. If it contains a few of the parameters then the rest of the parameters are calculated with the help of different formulas.

Cross Plotting

The different reservoir parameters that are related to each other are plotted against each other to estimate that where actually the high probability area does lie.

Reserve Estimation

This phase contains three parts of volumetric method, material balance method and decline curve analysis

Volumetric Method

As the name suggests, this method requires the volume of the reservoir to be calculated through maps. This method is carried out in the early phases of exploration to find the amount of Oil and Gas in place.

Material Balance Method

This method is carried out in the intermediary stages of the exploration and thus the production of Oil and Gas is estimated.

Decline Curve Analysis

This method is carried out in the last stages when most of the Oil and Gas is already discovered and thus the decline in the production rate is estimated with the help of this method.

Process Flow Diagram

Below is a diagram that demonstrates the important modules and processes needed to carry out the Reserve Estimation of Oil and Gas. 

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Explanation of these modules would be provided to you in my next post ... :-)

INTRODUCTION - OIL & GAS RESERVE ESTIMATION SOFTWARE

INTRODUCTION - OIL & GAS RESERVE ESTIMATION SOFTWARE
Geologists and Geophysicists in the Oil and Gas Industry require the help of a Petro physicist to provide them with the required information regarding the properties of different rocks. The introduction of Petro physics software will help these professionals to estimate the oil and gas reserves present in a particular Area of Interest.


Reserve Estimation Methods
There two more common methods of oil and gas reserve estimation are volumetric estimation and material balance. Other methods include decline curve analysis and reservoir stimulation.


1)Volumetric Estimation
Volumetric estimation is the method applied during the early delineation and development of a field. In this method, standard reserve equation is used with appropriate reservoir parameters which include

• Area, Thickness, Porosity, Water Saturation, Formation Volume Factor, Recovery Factor.

Steps The steps performed in volumetric estimation are

• Determination of Rock Volume, Determination of Average Porosity, Determination of Water Saturation to obtain hydrocarbon saturation and volume correction of hydrocarbon at atmospheric pressure and temperature.

Data Required The data used for this method includes

• Seismic, Well Log, Core Data, Bottom Hole Pressure, Temperature Data, Fluid Sample Information, Well test result

The data can also be used to develop various sub-surface and cross-sectional maps with the help of the Geographical Information System and Digital Image Processing methods using the required Computer Graphics.


Summary In simple words, volume of the particular field is calculated by measuring its area in square kilometers and then multiplying the area with the depth of the field. The volume will include the stones, hydrocarbons and space. The percentage of the stones and space will be subtracted from the total percentage of the field which gives the percentage of the hydrocarbons present in the field. Thus, the amount of hydrocarbons present in the field is calculated.


2) Material Balance Material balance is the more reliable method as the depletion proceeds and adequate data is made available. The production data includes production volume, reservoir pressure and temperature, fluid analysis data, log data, core data and drive mechanism.


3) Decline Curve Analysis Decline curve analysis is the method used in which production decline curve is analyzed which provides the estimation of remaining oil and gas reserves, future expected production rate, remaining productive life of well or reservoir.

Below is a video which demonstrates some of what we are trying to achieve by making this software.