petropy

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PetroPy - Petrophysical Analysis

PetroPy - 岩石物理分析

Quick Reference

快速参考

python

import petropy as pp

python

import petropy as pp

Load and inspect

加载并检查数据

log = pp.Log('well.las') print(log.keys()) # Available curves depth, gr = log['DEPT'], log['GR']

log = pp.Log('well.las') print(log.keys()) # 可用曲线 depth, gr = log['DEPT'], log['GR']

Calculate properties

计算物性参数

log.shale_volume(gr_curve='GR', gr_clean=20, gr_shale=120) log.formation_porosity(rhob_curve='RHOB', rhob_matrix=2.65, rhob_fluid=1.0) log.water_saturation(method='archie', rt_curve='RT', porosity_curve='PHIT', rw=0.05) log.permeability(method='timur', porosity_curve='PHIT', sw_curve='SW')

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Key Classes

核心类

Class	Purpose
`Log`	Main well log container, extends lasio.LASFile
`electrofacies`	Facies classification utilities
`Formations`	Zone/formation management

类名	用途
`Log`	主要测井数据容器，继承自lasio.LASFile
`electrofacies`	相分类工具
`Formations`	层段/地层管理

Essential Operations

关键操作

Shale Volume (Vsh)

泥质含量（Vsh）

python

log.shale_volume(
    gr_curve='GR',
    gr_clean=20,           # GR of clean sand (API)
    gr_shale=120,          # GR of shale (API)
    method='linear'        # or 'larionov_young', 'larionov_old', 'clavier'
)
vsh = log['VSH']

python

log.shale_volume(
    gr_curve='GR',
    gr_clean=20,           # 纯净砂岩的伽马射线值（API）
    gr_shale=120,          # 泥岩的伽马射线值（API）
    method='linear'        # 可选方法：'larionov_young', 'larionov_old', 'clavier'
)
vsh = log['VSH']

Porosity

孔隙度

python

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python

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Density porosity with shale correction

带泥质校正的密度孔隙度

log.formation_porosity( rhob_curve='RHOB', rhob_matrix=2.65, # g/cc (sandstone) rhob_fluid=1.0, # g/cc (water) rhob_shale=2.45, # optional shale correction vsh_curve='VSH' # requires VSH curve ) phi = log['PHIT']

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log.formation_porosity( rhob_curve='RHOB', rhob_matrix=2.65, # 骨架密度（g/cc，砂岩） rhob_fluid=1.0, # 流体密度（g/cc，水） rhob_shale=2.45, # 可选泥质校正参数 vsh_curve='VSH' # 需要VSH曲线 ) phi = log['PHIT']

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Water Saturation

含水饱和度

python

log.water_saturation(
    method='archie',       # or 'simandoux', 'indonesia'
    rt_curve='RT',
    porosity_curve='PHIT',
    rw=0.05,               # Formation water resistivity (ohm-m)
    a=1.0, m=2.0, n=2.0    # Archie parameters
)
sw = log['SW']

python

log.water_saturation(
    method='archie',       # 可选方法：'simandoux', 'indonesia'
    rt_curve='RT',
    porosity_curve='PHIT',
    rw=0.05,               # 地层水电阻率（ohm-m）
    a=1.0, m=2.0, n=2.0    # Archie参数
)
sw = log['SW']

Permeability

渗透率

python

log.permeability(
    method='timur',        # or 'coates'
    porosity_curve='PHIT',
    sw_curve='SW'
)
perm = log['PERM']         # Result in mD

python

log.permeability(
    method='timur',        # 可选方法：'coates'
    porosity_curve='PHIT',
    sw_curve='SW'
)
perm = log['PERM']         # 结果单位为mD

Pay Flag and Net Pay

产层标识与净产层厚度

python

import numpy as np
pay = (log['VSH'] < 0.4) & (log['PHIT'] > 0.08) & (log['SW'] < 0.6)
log['PAY'] = pay.astype(float)
net_pay = np.sum(pay) * log.step

python

import numpy as np
pay = (log['VSH'] < 0.4) & (log['PHIT'] > 0.08) & (log['SW'] < 0.6)
log['PAY'] = pay.astype(float)
net_pay = np.sum(pay) * log.step

Export Results

导出结果

python

log.to_las('well_interpreted.las')

python

log.to_las('well_interpreted.las')

Or to CSV

或导出为CSV

import pandas as pd df = pd.DataFrame({'DEPT': log['DEPT'], 'VSH': log['VSH'], 'PHIT': log['PHIT'], 'SW': log['SW']}) df.to_csv('results.csv', index=False)

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import pandas as pd df = pd.DataFrame({'DEPT': log['DEPT'], 'VSH': log['VSH'], 'PHIT': log['PHIT'], 'SW': log['SW']}) df.to_csv('results.csv', index=False)

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Archie Parameters

Archie参数

Parameter	Symbol	Range	Description
Tortuosity	a	0.6-1.0	Formation factor coefficient
Cementation	m	1.8-2.2	Pore geometry factor
Saturation exp	n	1.8-2.2	Wettability factor

参数	符号	范围	描述
迂曲度	a	0.6-1.0	地层系数
胶结指数	m	1.8-2.2	孔隙几何因子
饱和度指数	n	1.8-2.2	润湿性因子

Matrix Properties

骨架物性参数

Lithology	rhob (g/cc)	nphi (v/v)	DT (us/ft)
Sandstone	2.65	-0.02	55.5
Limestone	2.71	0.00	47.5
Dolomite	2.87	0.02	43.5
Shale	2.45	0.30-0.45	70-130

岩性	rhob (g/cc)	nphi (v/v)	DT (us/ft)
砂岩	2.65	-0.02	55.5
石灰岩	2.71	0.00	47.5
白云岩	2.87	0.02	43.5
泥岩	2.45	0.30-0.45	70-130

When to Use vs Alternatives

工具选择对比

Tool	Best For
petropy	Automated formation evaluation, standard petrophysical workflows
welly	Well data management, curve processing, multi-well projects
custom calculations	Non-standard equations, full control over methodology

Use petropy when you need a streamlined formation evaluation pipeline: Vsh, porosity, Sw, permeability, and pay flags with standard methods (Archie, Simandoux, Timur). It extends lasio so file I/O is built in.

Use welly instead when your focus is data management, curve QC, and multi-well projects rather than petrophysical calculations.

Use custom calculations instead when you need non-standard saturation models, proprietary equations, or more control over the computation steps than petropy's built-in methods provide.

工具	适用场景
petropy	自动化地层评价、标准化岩石物理工作流
welly	井数据管理、曲线处理、多井项目
自定义计算	非标准方程、完全控制计算方法

选择petropy的场景：当你需要一套精简的地层评价流程时，包括泥质含量、孔隙度、含水饱和度、渗透率及产层标识的标准化计算（Archie、Simandoux、Timur方法）。它继承自lasio，内置文件读写功能。

选择welly的场景：当你的工作重点是数据管理、曲线质量控制和多井项目，而非岩石物理计算时。

选择自定义计算的场景：当你需要非标准饱和度模型、专有方程，或需要比petropy内置方法更高的计算控制度时。

Common Workflows

常见工作流

Complete formation evaluation from raw logs

基于原始测井曲线的完整地层评价

- [ ] Load well with `pp.Log('well.las')`, verify required curves exist
- [ ] Pick clean sand and shale GR values from histogram or crossplot
- [ ] Compute shale volume: `log.shale_volume()`
- [ ] Compute porosity: `log.formation_porosity()` with matrix parameters
- [ ] Determine Rw from water zone or catalog; set Archie parameters
- [ ] Compute water saturation: `log.water_saturation()`
- [ ] Compute permeability: `log.permeability()`
- [ ] Apply pay flag cutoffs (Vsh, porosity, Sw) and calculate net pay
- [ ] Export interpreted log to LAS or CSV

- [ ] 使用`pp.Log('well.las')`加载井数据，验证所需曲线是否存在
- [ ] 通过直方图或交会图选取纯净砂岩和泥岩的伽马射线值
- [ ] 计算泥质含量：`log.shale_volume()`
- [ ] 结合骨架参数计算孔隙度：`log.formation_porosity()`
- [ ] 通过水层或参数目录确定Rw，设置Archie参数
- [ ] 计算含水饱和度：`log.water_saturation()`
- [ ] 计算渗透率：`log.permeability()`
- [ ] 应用产层标识阈值（泥质含量、孔隙度、含水饱和度）并计算净产层厚度
- [ ] 将解释后的测井数据导出为LAS或CSV格式

References

参考资料

Calculations - Porosity, saturation, and permeability equations
Fluid Properties - Fluid property models and correlations

计算方法 - 孔隙度、饱和度及渗透率计算公式
流体物性 - 流体物性模型与相关性

Scripts

脚本

scripts/formation_evaluation.py - Complete formation evaluation workflow

scripts/formation_evaluation.py - 完整地层评价工作流脚本