Concept Systems’ 4D services team offers expert analyses to assess the feasibility of a planned 4D program and develop optimized survey designs for repeatability and cost-efficient operations. The design and planning phase is comprised of two key elements:
- Baseline review & feasibility
- Monitor survey design & planning
Baseline Review and Feasibility
To understand the likely issues that will impact the feasibility and shooting of a 4D monitor survey, the following analyses are performed:
- Data loading and QC - to establish the integrity and completeness of the data
- Data stability - spatial navigation analysis of inter-spread attributes (cable separation, source to receiver offsets, etc.) to identify out-of-spec attributes; this provides a view of the stability of the positioning data and whether navigation re-processing is required
- Feather analysis - spatial and line-based analysis to identify potential feather matching problems
- Infill analysis- identifies how much re-shoot/infill data is present in critical areas of the survey and estimates the potential effects on the monitor survey
- Undershoot analysis - using the best known positions of field assets (vessels, streamers, etc) provides an analysis of the impact of these on key 4D targets
- Gun issues - data analysis to identify and report gun sequencing issues and anomalies that could affect the shooting plan for a 4D survey
All output images, plots and reports are uploaded to Concept Systems e-services for immediate access by the client.
Monitor Survey Design & Planning
The monitor survey is designed in consideration of issues found in the baseline review and the economics/practicalities of conducting the survey. This phase involves generating source pre-plots from baseline data and creating feather plots from the original receiver data.
In order to select an optimum geometry, baseline shot data is extracted and conditioned to optimize repeatability within the confines of economic viability. Once an agreed geometry is determined a number of deliverables are provided for the acquisition phase including:
- Field acquisition plots (including all surface/subsurface features)
- Acquisition summary (line list, direction, feather, etc)
- Survey-wide feather map and baseline feather plots (per line)
- Pre-plot generation to drive the acquisition system (e.g. Spectra 4D, ORCA 4D)
- Anomaly summary - issues to consider during acquisition (short/long shot intervals, duplicate shots, merged lines, etc
- Undershoot diagrams - PowerPoint representation of undershoot plan
All output images, plots, ASCII files and reports are placed on Concept Systems’ e-services for immediate access by the client.
