GB/T 33684-2017 (English Version)

Standard No.: GB/T 33684-2017
Language: Chinese, Available in English version
Release Date: 2017
Published By: General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest: GB/T 33684-2017

Scope: Requirements for the basic work, interpretation procedures, interpretation quality inspection and submission of interpretation results of two-dimensional and three-dimensional data interpretation of oil and gas seismic exploration. This standard applies to the interpretation of two-dimensional and three-dimensional data of oil and gas seismic exploration.

Introduction

Analysis of the core content of the standard

Technical modules	Requirements for 2D interpretation	Differences in 3D interpretation	Quality control indicators
Structural interpretation	Network interpretation of backbone profiles, fault classification (Grade I-III)	Volume interpretation + time slice verification, fault identification accuracy 0.5 phase	Plane position error ≤1mm, depth relative error ≤3%
Horizontal calibration	Synthetic record/VSP calibration, phase consistency required ≥60%		Calibration error ≤1/2 phase
Velocity analysis	Integrate sonic logging, VSP and velocity spectrum to establish space-varying velocity field		Allowable error ≤5% in mountainous areas

Key technical innovations

Seismic geological layer code system: Adopt the T_{ab}^{cd} coding rule, where:

a=system/system code (such as J2 for Middle Jurassic)
b=first letter of the group name (such as s for Shahejie Formation)
c=segment sequence/azimuth (1 for lower segment)
d=oil and gas layer number

Example: class="instrument">T_{E3s}^{1-2} represents the top surface of the 2nd oil group of the first section of the Shahejie Formation in the Oligocene

Key points for implementation

Data preparation stage: It is necessary to collect 12 types of basic data such as survey line location map, velocity spectrum, drilling stratification, etc. (Standard 4.1 clause)
3D interpretation process:
- Establishment of backbone profile network→Stratum body tracking→Fault space combination
- Time slice verification requires that the longitudinal profile usage rate is ＞25%
Result verification: Use the drilling conformity inspection formula:
η=(a₀+b₀+c₀)/(a+b+c)×100% ≥70% is qualified

Solutions to common problems

Problem type	Standard clause	Handling suggestion
Fault plane combination contradiction	5.3.3/6.1.2	Check the section inclination change rate ≤15°/km
Large time-to-depth conversion error	8.3.1	Add VSP velocity control points, and the density should be increased to 2km/point in mountainous areas

GB/T 33684-2017 history

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