是否有一个R包来解析地球物理"Log标准“文件(.las文件)？

Question

是否有一个R包可以读取.las文件，即斯伦贝谢Log Ascii标准文件？

它应该能够读取las 2.0文件。

请注意：

• 我不是在这里谈论激光雷达.las文件。
• 我指的是地球物理测井文件(不是用于计算机应用程序、恶魔之类的日志文件)。

在互联网上搜索R、Las和Logfiles会给我带来太多的红鲱鱼。

评论中提供的最新情况：

我还在考虑使用R语言绑定的脚本或API。

到目前为止，我发现了以下脚本：

• las2witsml -红宝石脚本
• Text-LAS-Parser-0.01 - perl脚本

然而，到目前为止，所有这些脚本在我看来还不太成熟。

斯伦贝谢还提供了一个免费的软件包“日志数据工具箱，但它只能在Windows下运行，并且可能与非英语版本的Windows有兼容性问题(如果我没记错的话)。

堪萨斯地质调查局有一个复杂java小程序，但是对于大型.las输入文件来说，它有点迟缓。

有一个ruby项目和一个python项目。另外，请参阅此链接获得一组不错的las文件。

Answer 1

回答我自己的问题：

现在有一个python库，拉西奥，它运行得很好。它可以是从R呼叫，也可以通过system2()函数实现；输出可以被提取到R数据结构中。另一种可能是将lasfile对象序列化为JSON，保存为文件并从R重新导入，也许我会用代码示例扩展这个答案，但我现在没有时间。

• 拉西奥 on github
• lasio实例 -笔记本底部的图解

Answer 2

2021年答复：

拉索尔斯

紫罗兰醇是github上的一个R包，用于读取Log标准v2.0文件。

它还提供了基本的绘图，并写入las文件格式。

要从r命令行安装(也可以通过其他方式安装)：

devtools::install_github("Gitmaxwell/lastools")

要加载lastools，请读取las文件并在R中显示内容：

library(lastools)
las_file <- "your-sample.las"
las <- read_las(las_file)
print(las)

拉萨

拉萨 (在测试版测试中，2021年早期)，Lasr主要设计用于高速、大批量地导入LAS文件。

从r命令行安装：

if (!require('devtools')) install.packages('devtools')
library(devtools)
install_github('https://github.com/donald-keighley/lasr')

加载lasr，读取和显示las文件内容的示例：

library(lasr)
las = read.las(system.file("extdata", "las_3_cwls.las", package = "lasr"))

#Display the WELL section
head(las$well, 10)

Answer 3

我做了我的个人(适合我的目的)使用一个良好的日志las2文件阅读器。它有两个步骤: 1.创建要读取和附加的*.las文件列表；2.读取*.las文件的数量并附加到单个数据框架中。这两种代码都在2016年用标准商业软件包创建的一组*.las文件上进行了测试--在R3.2.4(64位)下的Windows10中。

代码-1用于读取和创建运行代码-2的*.las文件的简单文件列表

# Read the file having list of well-log LAS files
# Create a R-Object [wellname, path, filename] for LAS reader
# Create filelist from DOS prompt dir *.las > filelist.dat
# G Srikanth 29-May-2016
#
library(stringr)
defaultworkdir <- readline("What is the file path? ")
setwd(defaultworkdir)
welllistfile <- readline("What is the well list file? ")
listfilelines <- readLines(con = welllistfile, skipNul = TRUE)
#
#      search for "Directory of " to get the LAS data folder = lasfolder
#      search for "File(s)" to get the number of files = nlasfiles, linenumber
#      the data file names are before the "Files(s)" line = lasfilenames() char vector of length nlasfiles
#
oneline <- listfilelines[grep("Directory of ",listfilelines)]
lasfilepath <- sub(" Directory of ","",oneline)
oneline <- listfilelines[grep(" File",listfilelines)]
# modified from http://stackoverflow.com/questions/2261079/how-to-trim-leading-and-trailing-whitespace-in-r
numberoflasfiles <- as.numeric(word(sub("^\\s+", "", oneline),1))

# file names occur from - to in the DOS list read-in
fromline <- as.numeric(grep(" File",listfilelines)) -numberoflasfiles

# extract the last word from the fromline - numberoflasfiles times and load into suitable data structure
#     tail(strsplit(oneline,split=" ")[[1]],1)   --- taken from 
#     http://stackoverflow.com/questions/17658216/extract-last-word-in-string-in-r

lasfile <- c(1:numberoflasfiles)
for (n in 1 : numberoflasfiles) 
{
  oneline <- listfilelines[fromline]
  lasfile[n] <- tail(strsplit(oneline,split=" ")[[1]],1)
  fromline=fromline+1
}
# print (lasfile)
rm(fromline)
lasfile<- paste(lasfilepath,"\\",lasfile,sep="")
# print(lasfile)
# temp <- readLines(con=lasfile[1], skipNul = TRUE) 
#
save(lasfile,file="lasfiles.Rdat")

代码-2读取多个*.las文件并构造单个数据框架。

# Read the list of lasfiles to read
# open each las file and get data

# G Srikanth 29 May 2016

#                                                   install.packages("data.table")
# 1. set working directory and read the file list
library(stringr)
library(data.table)
defaultworkdir <- readline("What is the file path? ")
setwd(defaultworkdir)
lasfilelist <- readline("What is the well list file? ")
load(lasfilelist)
welllogdata <- data.frame()

#     load("lasfiles.Rdat")    name of saved file
#     determine number of well files
nwells <- length(lasfile)
uwi<-c(1:nwells)
# 2. Main read loop for each well las file in directory
for (wellno in 1:nwells)
{
  # 2a. Get uwi
  # 2b. Get curve names
  # 2c. Read the curve data

  # LAS files have all the headers within first 100 lines
  # read 100 lines into a vector
  headerlines <- readLines(con = lasfile[wellno], n=100L, ok=TRUE, skipNul = TRUE)
  # extract uwi  NOTE - many las files write only proper well name and not UWI. in such case replace UWI with WELL in next line
    oneline <- headerlines[grep(" UWI",headerlines)]
    # remove multiple spaces with gsub() extract 3rd word with word()
    #     ref: http://rfunction.com/archives/2354
    uwi[wellno]<-word(gsub("\\s+"," ",str_trim(oneline)),3)
  # extract curve information and data location
    #locate ~A  in the headerlines. This has the log names.
    oneline <- headerlines[grep("~A",headerlines)]# line having curves names
    oneline <- gsub("\\s+"," ",str_trim(oneline)) # trim leading trailing and extra blanks
    ncurves <- str_count(oneline, " ")
    # ncurves <- str_count(gsub("\\s+"," ",str_trim(headerlines[grep("~A",headerlines)]))," ")
    # The next record in data file is numeric las data.
    dataline <- as.numeric(grep("~A",headerlines)+1)
    curvenameline <- as.numeric(grep("~A",headerlines)- ncurves) 
    # curve names start at curvenameline and contine for ncurves. The first word in each line is curve name
    logname <- c(1:ncurves)
    for (nc in 1:ncurves)
    {
      logname[nc] <- word(gsub("\\s+"," ",str_trim(headerlines[curvenameline+(nc-1)])),1)
    }
  # read the data matrix from the line - dataline in the well las file
    # null value used in the las file
    lasnull <- word(gsub("\\s+"," ",str_trim(headerlines[grep(" NULL",headerlines)])),3)
    temp<- read.table(lasfile[wellno], header=F, na.strings=lasnull, skip=dataline-1, col.names = logname)
    temp <- merge(temp,uwi[wellno])
    names(temp) <- c(logname,"uwi")
  # concatenate this data into a single data-frame. use the lognames to merge.
    if (wellno == 1) welldata <- temp else welldata <- rbind.fill(welldata, temp)    #rbind doesnt merge with different names, Thanks to stackoverflow!
        # to clean the logname vector between files
    rm(logname)
}
save(welldata,"welldata.Rdat")

希望它有用！