SPS 3.0 Update of the Progress of the SPS Subgroup of the SEG Technical Standards Committee Cignoli, J.E.; Green, P.C.; Hubbell, S.E.; Moffitt, R.G.; Siddiquee, F; Bowes, A.W.; LaFon, S.K.; Musser, J.A. (Saudi Aramco) September, 2011

Current SPS v2.1 Point Record (R & S) Specifications Item Definition of field Cols Format Min. to max Default Just. units 1 Record identification 1-1 A1 “S” or “R” None n/a   2 Line name 2-11 F10.2 -999999.99 to 9999999.99 Right 3 Point number 12-21 + 22-23 Blank 4 Point index 24-24 I1 1 to 9 5 Point code 25-26 A2 A# Left 6 Static correction 27-30 I4 -999 to 9999 ms 7 Point depth 31-34 F4.1 0 to 99.9 Header defined 8 Seismic datum 35-38 9 Uphole time 39-40 I2 0 to 99 10 Water depth 41-46 F6.1 0 to 9999.9 11 Map grid easting 47-55 F9.1 12 Map grid northing 56-65 F10.1 13 Surface elevation 66-71 -999.9 to 9999.9 14 Day of year 72-74 I3 1 to 999 15 Time “hhmmss” 75-80 3I2 000000 to 235959

Proposed SPS v3.0 Point Record (R & S) Specifications Item Definition of field Cols Format Min. to max Default Just. units 1 record identification 1-1 A1 “S” or “R” None n/a   2 line name 2-17 F16.5 -999999999.99999 to 9999999999.99999 Right 3 point number 18-33 + 34-35 Blank 4 point index 36-38 I3 1 to 999 5 point code 39-41 A3 A## Left 6 point depth 42-49 F8.2 0 to 99999.99 Header defined 7 tide height 50-54 F5.2 -9.99 to 99.99 8 water depth 55-62 9 map grid easting 63-72 F10.2 10 map grid northing 73-83 F11.2 11 surface elevation 84-91 -9999.99 to 99999.99 12 day of year (Julian day) 92-94 13 time “hhmmss” 95-100 3I2 000000 to 235959 14 GPS time* (SEGD Timestamp) 101-121 F21.6 -9223372036854.123456 to 9223372036854.123456 Seconds * The GPS Time / SEGD Timestamp is the time in seconds with microsecond precision since 06 January 1980 00:00:00 (GPS epoch). Dates and times before 06 January 1980 will have a negative GPS Time value.

Current SPS v2.1 Relation Record (X) Specifications Item Definition of field Cols Format Min. to max Default Just. 1 Record identification 1-1 A1 “X” None n/a 2 Field tape number 2-7 3A2 free right 3 Field record number 8-15 I8 0 to 16777215 4 Field record increment 16-16 I1 1 to 9 5 Instrument code 17-17 6 Line name 18-27 F10.2 -999999.99 to 9999999.99 7 Point number 28-37 999999.99 to 9999999.99 8 Point index 38-38 F4.1I1 9 From channel 39-43 I5 1 to 99999 10 To channel 44-48 11 Channel increment 49-49 Blank1 12 50-59 13 From receiver 60-69 14 To receiver 70-79 15 Receiver index 80-80

Proposed SPS v3.0 Relation Record (X) Specifications Item Definition of field Cols Format Min. to max Default Just. 1 record identification 1-1 A1 “X” None n/a 2 field tape number 2-13 6A2 free right 3 field record number 14-21 I8 0 to 16777215 4 field record increment 22-23 I2 1 to 99 5 instrument code 24-24 1 to 9 6 source line name 25-40 F16.5 -999999999.99999 to 9999999999.99999 7 source point number 41-56 8 source point index 57-59 I3 1 to 999 9 from channel number 60-66 I7 1 to 9999999 10 to channel number 67-73 11 channel number increment 74-76 12 receiver line name 77-92 13 from receiver point number 93-108 14 to receiver point number 109-124 15 receiver point index 125-127

SPS 3.0 Considerations and Features SPS v3.0 should be fully compatible with SEGD v3.0. Proposed SPS v3.0 records all require less than 150 columns (as recommended by OGP) and still have room for expansion before that limit is reached. SEGD supports Short Mother Records (SMR), in which multiple source events are recorded in a single record, resulting in a many-to-one relation of source point records to an ffid on tape. This will require further generalization of the relational (X) records to allow generation of daughter records with unique ffids from the mother record. This may be a new record or file type (similar to X) or It may be a modification of the existing Relational (X) file with added records defining the daughter data Additional input relating to handling SMRs and subsequent separated daughter records is solicited from industry participants. The current recommendations are Aramco-centric mainly because we have received little feedback from seismic industry service providers when solicited. GPS time with microsecond fidelity is added to allow accurate source separation in high-productivity acquisition (such as ISS).

SPS 3.0 Considerations and Features (cont.) Comma delimiting of record entries is being considered to improve robustness of the formats. [Comma-Space] delimiting is also being considered to help keep the records relatively easy to scan by eye. OBC data acquisition easily fits within the proposed SPS 3.0 definitions. Current and Future High-Channel Count crews require the SEGY format to increase the current channel limitation (32,767) to be compatible with SEGD (16,777,215). Consideration should be given in future versions of all formats (SPS, SEGD, SEGY, etc.) for robust handling of Common Receiver Gather data, such as acquired by nodes and other wireless systems. For SPS files, this can be achieved by a reversal of the roles of S and R stations within the X files. Further development of SPS Header Blocks and Templates for specific acquisition technologies and schemes (such as, surface sources, explosives, airgun arrays, buried receivers, seabed receivers, etc.) are under development. Documentation will proceed upon approval of proposed formats.