Currently supports only version 2.0 of LAS Specification. For more information about this format, see the Canadian Well Logging Society product page.
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Installing
NPM
$npm install las-jsYarn
$yarn add las-jsBrowser
<script defer src="https://cdn.jsdelivr.net/npm/las-js/dist/browser.js"></srcipt>
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Usage
import/require las-js module
Node
// common js const { Las } = require('las-js'); // esm import { Las } from 'las-js'; const myLas = new Las(`./sample/example1.las`);
You can also pass LAS file contents directly to constructor
// common js const { Las } = require('las-js'); const fs = require('fs'); const data = fs.readFileSync(`./sample/example1.las`, { encoding: 'utf8' }); // add loadFile: false to constructor options const myLas = new Las(data, { loadFile: false });
Browser
las-js adds a global class Lasjs
const input = document.getElementById('file-input');
input.addEventListener('change', async e => {
const file = e.target.files[0];
const myLas = new Lasjs(file);
});
// or
const myLas = new Lasjs('https://raw.githubusercontent.com/iykekings/las-js/master/src/__test__/sample/A10.las'); // url - only on browser-
Read data
Use Laspy.data to get a 2-dimensional array containing the readings of each log, Or Lasjs.dataStripped to get the same as above but with all rows containing null values stripped off
async function read() { try { const data = await myLas.data(); console.log(data); /** [[2650.0, 177.825, -999.25, -999.25], [2650.5, 182.5, -999.25,-999.25], [2651.0,180.162, -999.25, -999.25], [2651.5, 177.825, -999.25, -999.25], [2652.0, 177.825, -999.25, -999.25] ...] */ const dataStripped = await myLas.dataStripped(); console.log(dataStripped); /** [[2657.5, 212.002, 0.16665, 1951.74597], [2658.0, 201.44, 0.1966, 1788.50696], [2658.5, 204.314, 0.21004, 1723.21204], [2659.0, 212.075, 0.22888, 1638.328], [2659.5, 243.536, 0.22439, 1657.91699]...] */ } catch (error) { console.log(error); } }
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Get the log headers
// ... const headers = await myLas.header(); console.log(headers); // ['DEPTH', 'GR', 'NPHI', 'RHOB'] // ...
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Get the log headers descriptions
//... const headerAndDescr = await myLas.headerAndDescr(); console.log(headerAndDescr) // {DEPTH: 'DEPTH', GR: 'Gamma Ray', NPHI: 'Neutron Porosity', RHOB: 'Bulk density'} // ...
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Get a particular column, say Gamma Ray log
// ... const gammaRay = await myLas.column('GR'); console.log(gammaRay); // [-999.25, -999.25, -999.25, -999.25, -999.25, 122.03, 123.14, ...] // ...
// ... // get column with null values stripped const gammaRay = await myLas.columnStripped('GR'); console.log(gammaRay); // [61.61, 59.99, 54.02, 50.87, 54.68, 64.39, 77.96, ...] // ...
Note this returns the column, after all the data has been stripped off their null values, which means that valid data in a particular column would be stripped off if there is another column that has a null value at that particular row
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Get the Well Parameters
1. descr - Description/ Full name of the well parameter 2. units - Its unit measurements 3. value - Value// ... const well = await myLas.wellParams() const start = well.STRT.value // 1670.0 const stop = well.STOP.value // 1669.75 const null_value = well.NULL.value // -999.25 // Any other well parameter present in the file, can be gotten with the same syntax above // ...
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Get the Curve Parameters
1. descr - Description/ Full name of the log column 2. units - Unit of the log column measurements 3. value - API value of the log column// ... const curve = await myLas.curveParams() const NPHI = curve.NPHI.descr // 'Neutron Porosity' const RHOB = curve.RHOB.descr // 'Bulk density' // This is the same for all log column present in the file // ...
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Get the Parameters of the well
1. descr - Description/ Full name of the log column 2. units - Unit of the log column measurements 3. value - API value of the log column// ... const param = await myLas.logParams(); // 'BOTTOM HOLE TEMPERATURE' const BHT = param.BHT.descr // 'BOTTOM HOLE TEMPERATURE' const BHTValaue = param.BHT.value // 35.5 const BHTUnits = param.BHT.units // 'DEGC' // This is the same for all well parameters present in the file // ...
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Get the number of rows and columns
// ... const numRows = await myLas.rowCount() // 4 const numColumns = await myLas.columnCount() // 3081 // ...
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Get the version and wrap
// ... const version = await myLas.version() // '2.0' const wrap = await myLas.wrap() // true // ...
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Get other information
// ... const other = await myLas.other() console.log(other) // Note: The logging tools became stuck at 625 metres causing the data between 625 metres and 615 metres to be invalid. // ...
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Export to CSV
For node, this writes a csv file to the current working directory, with headers of the well and data section only for node. For browser, this returns a File Blob, that can be downloaded by using URL.createObjectURL
//... await myLas.toCsv('result') // result.csv has been created Successfully! //...
result.csv
DEPT RHOB GR NPHI 0.5 -999.25 -999.25 -0.08 1.0 -999.25 -999.25 -0.08 1.5 -999.25 -999.25 -0.04 ... ... ... ... 1.3 -999.25 -999.25 -0.08 Or get the version of csv with null values stripped
// ... await myLas.toCsvStripped('clean') // clean.csv has been created Successfully! // ...
clean.csv
DEPT RHOB GR NPHI 80.5 2.771 18.6 -6.08 81.0 2.761 17.4 -6.0 81.5 2.752 16.4 -5.96 ... ... ... ... 80.5 2.762 16.2 -5.06 -
Browser and Node Supports
las-js is written in typescript and compiles to es6.
- Browser Supports IE 10 and 11 - (doesn't yet support url) Doesn't support Opera Mini
- Node Tested 0n 8, 10 and 12
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las-js is an MIT-licensed open source project. You can help it grow by becoming a sponsor/supporter.Become a Patron!