GB/T 43126-2023

Technical specifications for shale oil geological sweet spot evaluation (English Version)

Standard No.

GB/T 43126-2023

Language

Chinese, Available in English version

Release Date

2023

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China

Latest

GB/T 43126-2023

Scope

This document specifies the evaluation parameters, evaluation methods and main results of geological sweet spots for medium-high maturity shale oil, interlayer shale oil and in-situ conversion shale oil. This document is applicable to the evaluation of geological sweet spots for medium-high maturity shale oil, interlayer shale oil and in-situ conversion shale oil.

Introduction

Analysis of the core content of the standard

This standard systematically constructs a three-dimensional technical system for the evaluation of shale oil geological sweet spots:

1. Shale-type shale oil: Based on 7 core parameters such as total organic carbon content (TOC) and vitrinite reflectance (Ro)
2. Interlayer-type shale oil: Highlighting 6 characteristic parameters such as effective porosity and permeability/crude oil viscosity ratio
3. In-situ conversion shale oil: Innovatively introduces the evaluation model of recoverable oil equivalent per unit mass of rock

---

Comparison of key technologies

Evaluation type	Core method	Key parameters	Applicable conditions
Shale type	Sweet spot index method/Threshold index method	TOC≥2%, Ro≥0.7%, Clay≤40%	More than 5 representative wells are required
Interlayer type	Movable oil saturation method	Por≥6%, K/μo≥0.5mD/(mPa·s)	Interlayer thickness 1-5m
In-situ conversion	Thermal simulation correction method	BOEpm≥25kg/t	Test well group data required

---

Implementation points

Data collection specifications

• Basic data requirements: Industrial oil flow well trial production ≥6 months, supporting pressure-maintaining coring data
• Key test items:
  - Shale type: TOC, Ro, Clay content
  - Interlayer type: porosity, permeability, crude oil viscosity
  - In-situ conversion: thermal simulation oil production

Economic evaluation model

Dynamic economic evaluation method is used, calculation formula:

EUR_BOE_{cut_off} = Σ[(1+IRR/100)ⁱ×(Capex_i+Opex_i)/(R_BOE×(P_BOE-Tax_BOE))]

The recommended IRR lower limit is ≥6%

---

Technology Evolution Analysis

Innovative breakthroughs of this standard compared with traditional evaluation methods:

1. Multi-parameter coupling: Establish TOC-Ro-ΔP_fh parameter linkage model
2. Crack correction: Introduce the fracture porosity (φ_f) compensation coefficient, correction formula:
   SW_index=(1+0.76φ_f²)×f_ratio×∏(EUR_BOE_i/EUR_BOE_{cut_off})
3. In-situ conversion quantification: Establishing a recoverable oil equivalent prediction model through thermal simulation experiments

Application case reference

Evaluation of shale oil in Chang 7 section of Ordos Basin:

• Using the sweet spot index method, TOC=4.2%, Ro=0.9%, He=15m
• Calculate SW_index=1.8, and determine the area of the sweet spot to be 82km²
• The actual development well EUR reached 21,000 m³, with a matching degree of ＞85%

GB/T 43126-2023 Referenced Document

• GB/T 33684-2017 Technical specification of seismic data interpretation

GB/T 43126-2023 history

• 2023 GB/T 43126-2023 Technical specifications for shale oil geological sweet spot evaluation