Capstone — onshore simultaneous-source
Learning objectives
- Describe N-array simultaneous-source field practice
- Quote typical productivity: 40–60 k VPs/day/crew
- Recognise cross-talk penalty as the limit on array count
- Identify BGP Oman / UAE as the reference deployments
Simultaneous-source acquisition overlaps vibroseis sweeps across multiple arrays separated by a few seconds and ± 100–200 ms random jitter, then separates contributions in processing. Productivity jumps from 15 k VPs/day (classical slip-sweep) to 40–60 k VPs/day per crew — the biggest onshore productivity leap since vibroseis itself.
Why arrays overlap
A vibroseis cycle is sweep (12 s) + listen (4 s) + move (30 s). Classical slip-sweep can overlap move-up of array N with sweep+listen of array N+1 — cycle drops to max(sweep+listen, move+slip-gap) ≈ 30 s. Simultaneous-source goes further: two or more arrays sweep within the same 10–15 s window, on non-overlapping sub-regions of the receiver spread. Random jitter of each array’s start time makes each array’s contribution incoherent in the others’ time reference.
Cross-talk limit
Deblending residual (cross-talk energy left over after separation) rises roughly as 5% per added array. With 2 arrays: 5% cross-talk, barely visible. With 4 arrays: 15% cross-talk, workable. With 6 arrays: 25% cross-talk, borderline for high-fidelity amplitude work. Most production crews sit at 3–4 arrays.
Real deployments
BGP Oman Khazzan block (2018–2021) — 4-array ISS running 45 k VPs/day. ADNOC onshore UAE (2020–2023) — 3-array fleets as standard practice. ExxonMobil Siberian pilot (2022) — 5-array demonstrator. Aramco has been an early adopter since 2014. Desert terrain is ideal: wide-open shot access, no environmental restrictions, easy coordination between fleets.
References
- Beasley, C. J., Chambers, R. E., Jiang, Z. (1998). A new look at simultaneous sources. SEG Annual Meeting Expanded Abstracts, 133–135.
- Berkhout, A. J. (2008). Changing the mindset in seismic data acquisition. The Leading Edge, 27(7), 924–938.
- Mahdad, A., Doulgeris, P., Blacquière, G. (2011). Separation of blended data by iterative estimation and subtraction of blending interference noise. Geophysics, 76(3), Q9–Q17.
- Cordsen, A., Galbraith, M., Peirce, J. (2000). Planning Land 3-D Seismic Surveys. SEG Geophysical Developments 9.