Equipment QC approaches in land seismic acquisition

Transcription

1 first break volume 33, Jue 2015 Earth Sciece for Eergy ad Eviromet Equipmet QC approaches i lad seismic acquisitio Steve Wilcox 1* aalyses the capabilities of the most popular lad acquisitio systems available today i terms of their ability to provide the observer with QC data. S ice the itroductio aroud 2003 of the first moder wireless lad acquisitio systems (see Pael 1), the market has see a variety of differet systems itroduced with a bled of differet features. Over the same time, the lad seismic market i North America has also udergoe a remarkable trasformatio, whereby the traditioal telemetry cable-based systems have lost their domiat positio, havig bee overhauled by the combiatio of various wireless solutios. I traditioal cabled systems, the observer had a clear view of his task cotrollig the operatio of the system. The status of the etire system was available to him i real-time, with QC data beig trasmitted from the field equipmet via telemetry cable. He could see the coditio of the batteries, ad direct the crew to replace them as required; he could see with a high degree of cofidece what wid or evirometal oise the sesors were pickig up; ad above all he could immediately detect if sesors were out of specificatio or cables were damaged. Thus, he had all the iformatio ecessary to acquire good quality seismic data. The Achilles heel of the operatios, of course, was the susceptibility of the telemetry cables to damage durig operatios ad a alterative to these was log sought. The itroductio of wireless systems removed the issues aroud cable-damage, ad their success reflected i their icreasig domiace i the North America market clearly shows that seismic cotractors usig them experiece operatioal beefits i doig so. Figure 1 gives a illustratio of the chage i relative market share from 2007 to 2011, ad idicatios are that wireless systems have further icreased their market share sice. There are, however, a umber of differeces i the capabilities of the differet systems available, most especially regardig their provisio of QC data to the system observer. Additioally, some systems have bee developed to offer some of the advatages of both cabled ad wireless systems, ad it is the itetio i this paper to address systems accordig to their capabilities rather tha their data trasmissio medium. The availability of QC data to the observer is ofte a cotetious subject, ad there is a body of opiio that with the high reliability of moder electroics, the effort ad complexity of providig this data to the observer is redudat. O the other had, others coted that this is depedet o the specifics of the seismic programme beig udertake. It is the purpose of this paper to: 1. Aalyse the capabilities of the most popular lad acquisitio systems available today i terms of their ability to provide the observer with QC data, categorizig the equipmet broadly ito three categories; 2. Aalyse the impact of each of these categories of equipmet o field operatios; 3. Discuss the variatios i field operatios i commo cotemporary acquisitio programmes; 4. Discuss which categories of system are best suited to which types of programme. Curret lad systems The mai lad systems available today are summarized, alog with a very brief descriptio of their operatig characteristics, i Table 1. Examiig this list, we ca coclude that those systems which utilize a wireless or cabled etwork ca both trasmit data i real-time ad commuicate QC data to a cetral uit, but that those systems which employ local recordig of seismic data are divided betwee those that make QC data available durig operatio by meas of some form of wireless trasmissio (either Persoal Area Network or Wireless Local Area Network) ad those that oly make QC data available at deploymet. Therefore, i terms of their QC data capability we ca broadly categorize these systems as: Blid QC data ot available durig acquisitio QC Capable QC data is retrievable durig acquisitio with some field effort Real-time QC QC data sampled at a suitably high rate ad trasmitted to cetral uit via a etwork to give effectively real-time status otificatio. Of course, allocatig each system to oly oe category is i may cases misleadig, as some systems have alterate capabilities depedig o how they are cofigured, therefore the categorizatio may be applied accordig to the Ve diagram i Figure 2. 1 Sercel. * Correspodig author, steve.wilcox@sercel.com 2015 EAGE 95

2 Earth Sciece for Eergy ad Eviromet first break volume 33, Jue 2015 System Data Recordig Method QC Data Retrieval Method I-Seis Sigma Wireless Seismic RT2 Autoseis HDR FairfieldNodal ZLAND Geospace GSX Iova Hawk Iova G3i Sercel UNITE Sercel 428XL Cableless local recordig or real time trasfer utilizig exteral wireless trasceiver Cableless real time wireless trasmissio. Optioal local recordig mode recetly itroduced Cableless local recordig. Data offload i rack Cableless local recordig. Data offload i rack Cableless local recordig. Data offload i rack Cableless local recordig. Data offload by wireless harvester or i rack Real time recordig utilizig telemetry cable Cableless local recordig. Data offload by wireless harvester or i rack. Optioal real-time trasmissio usig wireless etwork. Real time recordig utilizig telemetry cable Sercel Local recordig i cocetrators 508 XT Real time trasfer utilizig telemetry cable Schlumberger Real time recordig utilizig telemetry cable UiQ Table 1 Summary of mai cotemporary lad systems. Wireless trasfer utilizig iteral Persoal Area Network wireless trasceiver Trasmissio by wireless etwork to cetral uit At deploymet with field tool At deploymet with field tool Wireless trasfer utilizig iteral Persoal Area Network trasceiver Wireless trasfer utilizig Wireless Local Area Network trasceiver Trasmissio by telemetry cable etwork to cetral uit Wireless trasfer utilizig Wireless Local Area Network trasceiver. Trasmissio by telemetry cable etwork to cetral uit Trasmissio utilizig wireless etwork or telemetry cable etwork Trasmissio by telemetry cable etwork to cetral uit Field logistics impacts I order to assess the operatioal logistics of these differet system categories, it is felt ecessary to defie a set of key operatioal features to which a scorig ca be applied accordig to how they are impacted. The operatioal features cosidered here are: Ease of deploymet The scale ad degree of simplicity of the effort required by a crew to deploy ad brig a system ito operatio. This icludes orgaizatioal effort, redeploymet for roll-alog etc. Ease of operatio The scale ad degree of difficulty of the effort required by a crew to retrieve QC data durig operatio. This may iclude maitaiig the itegrity of a etwork Uptime The amout of time where the system is recordig. This may be egatively affected by weather, equipmet issues, cultural issues etc. ad may be reduced by coscious decisios to stop recordig due to QC data ot beig available as expected Data quality cofidece The degree of cofidece that the quality of the seismic data beig recorded is withi specificatio. The data quality may be egatively affected by wid or evirometal oise, by poor receiver couplig etc. Equipmet cofidece The degree of cofidece that data chaels are ot beig affected by battery issues, GPS issues, geophoe issues, equipmet theft, equipmet damage etc. Portability I geeral, the more fuctioality provided, the greater the weight of the equipmet. Also, with more fuctioality, geerally power cosumptio is higher resultig i a requiremet for more ad/or heavier batteries Five rakigs are defied, ragig from very low (o or very low impact) to very high (very high impact). Blid systems or those operatig as Blid systems are assessed as impactig the operatioal features as follows: EAGE

3 first break volume 33, Jue 2015 Earth Sciece for Eergy ad Eviromet Ease of deploymet - Very high Deploymet is straightforward, with little complexity ad the least crew effort Ease of operatio - Very high Operatio is straightforward, as o QC data is retrieved Uptime - Very high As there is o etwork ad o QC data to be reviewed, there is o dowtime as a result Data quality cofidece Very low It is ot possible to moitor for egative iflueces o data quality, therefore the system caot provide cofidece o the quality of the data Equipmet cofidece - Very low It is ot possible to moitor for degraded equipmet performace, therefore the system caot provide cofidece o the operability of the equipmet Portability - High Low fuctioality ad low power cosumptio result i the lowest weight. QC Capable systems are assessed as impactig the operatioal features as follows: Ease of deploymet - Very high Deploymet is straightforward, with little complexity ad low crew effort Ease of operatio - Low Field crew must be orgaized ad deployed to retrieve QC Data Uptime - High Relatively ifrequet samplig of QC Data ad o etwork to fail results i less opportuity for dowtime Data quality cofidece Moderate Relatively ifrequet samplig of QC Data icreases the probability that egative impacts o seismic data quality are detected Equipmet cofidece - High Eve a low frequecy samplig of QC Data ca esure that equipmet faults, failures, theft ad damage are detected i a sufficietly timely maer Portability - Moderate The icreased fuctioality icreases the weight of the equipmet, ad results i some icrease of power cosumptio resultig i a higher battery requiremet tha equivalet Blid systems Real-time systems are assessed as impactig the operatioal features as follows: Ease of deploymet - Very low Deploymet is relatively complex ad requires substatial field crew effort to deploy, alig ad brig ito operatio a cabled or wireless etwork Ease of operatio - Moderate Effort required to maitai the etwork durig operatio has some impact o the ease of operatio Uptime - Very low Equipmet reliability, damage or iterferece to the etwork, ad birddog/observer reactio to QC Data icreases the likelihood of productio dowtime Data quality cofidece Very high High frequecy samplig of the QC Data will result i the highest possible cofidece that good quality data is recorded Equipmet cofidece Very high High frequecy samplig of the QC Data will result i the highest possible cofidece i the itegrity of the field equipmet Portability - Low The icreased fuctioality ad icreased quatity of equipmet required for the etwork icreases the weight ad volume of the equipmet. This also icreases power cosumptio resultig i icreased battery requiremets. These assessmets are summarized i Table 2. The radar diagram show i Figure3 gives a more visual represetatio, ad serves to highlight the differeces i the Figure 1 Chage i relative ew sales by year of Cabled ad Wireless lad acquisitio systems i North America. Figure 2 Categories of lad seismic acquisitio systems EAGE 97

4 Earth Sciece for Eergy ad Eviromet first break volume 33, Jue 2015 Impact o Blid QC Capable Real time Ease of deploymet Very high Very high Very low Ease of operatio Very high Low Moderate Uptime Very high High Very low Data quality cofidece Very low Moderate Very high Equipmet cofidece Very low High Very high Portability High Moderate Low Table 2 Summary of impact o operatioal features by system category. Figure 3 Radar map of operatioal features by system category. fuctioal profiles of the three categories of system. A ideal system would have a plot ruig aroud the outside of the radar map, ad it is clear that all three categories have oe or more features that itersect with it, although they all diverge from the ideal i multiple areas. Oe coclusio that could be draw from this radar map is that Blid ad Real-time systems may have particular suitability for acquisitio programmes with specific priorities, whereas QC Capable systems may have more all-roud applicability. Acquisitio programmes I recet years, the traditioal image of a seismic cotractor acquirig data o a seismic programme that is specified by a cotract issued by a cliet, ad beig moitored cotiuously by a cliet represetative (birddog) has bee challeged. Ofte ow, seismic compaies speculatively udertake projects to build a library of data that ca be sold or leased o. Thus, rather tha the ivestmet for the data acquisitio beig bore by the cliet, the acquisitio compay bears the ivestmet cost themselves, with expectatios of a later retur. A additioal chage has bee the growth i demad for microseismic moitorig durig frackig. The operatioal performace requiremets o the equipmet for these projects are substatially differet tha for exploratio seismic. However, for acquisitio compaies they represet either a sigificat portio of their curret activity or a potetial ew source of reveue. So, if we defie three programme types that a acquisitio compay might frequetly udertake, we ca the aalyse how the previously defied operatioal features would be prioritized for each type: Proprietary survey the parameters are specified by a cliet, ad operatios moitored by a cliet represetative Speculative survey the compay makes a speculative ivestmet i acquirig the data for a library Frack moitorig the compay is egaged by a cliet to moitor for microseismic evets over the course of a well treatmet I order to profile the operatioal features of these programme types i terms of what is demaded of the acquisitio system used, we defie five levels of scorig ragig from very low priority to very high priority. Proprietary surveys: Durig Proprietary surveys, the cliet represetative will ormally work to esure that the highest quality of data is acquired. This may ofte be at the expese of productivity. However, the acquisitio compay will attempt to maitai as high a level of productivity as possible with as low operatig costs as possible. Ease of deploymet Moderate priority Ease of operatio Moderate priority Uptime Moderate priority Data quality cofidece Very high priority Equipmet cofidece Very high priority Portability Moderate priority Speculative surveys: I the case where a compay udertakes a speculative survey, it will decide itself how to cotrol data quality, perhaps utilizig risk maagemet techiques ad evirometal oise moitorig tools, but because the cost represets a ivestmet by the compay it will, of course, attempt to keep the programme cost as low as possible EAGE

5 first break volume 33, Jue 2015 Earth Sciece for Eergy ad Eviromet Ease of deploymet Very high priority Ease of operatio Very high priority Uptime Very high priority Data quality cofidece Low priority Equipmet cofidece Low priority Portability Very high priority Frack moitorig: Frack moitorig programmes are i some ways like proprietary surveys i as much as the cliet specifies the parameters ad will pay reasoable costs. However, as the programme is static much more ca be doe with the sesors to esure good data quality. Furthermore, as the fracture evets represet oe-time oly evets, the equipmet must have a high level of availability. Some frack moitorig surveys will explicitly require real-time data acquisitio. Ease of deploymet Very low priority Ease of operatio Moderate priority Uptime Very high priority Data quality cofidece Very high priority Equipmet cofidece Very high priority Portability Very low priority These priorities are summarized i Table 3. Expressig this oce more i a radar diagram as show i Figure 4 gives a visual represetatio, ad allows us to compare these profiles with the fuctioal profiles of the three categories of system defied previously. As ca be see, oe of the survey types exactly matches the profile of ay system category, but the closest matches are: Frack moitorig is most closely matched to real-time QC systems A importat divergece, however, is that if real-time acquisitio is required, the etwork must be closely maaged to avoid dowtime Speculative surveys are most closely matched to blid systems Proprietary surveys are most closely matched to QC capable systems However, measures should be take to esure that data quality specificatios are met. This could, for example, be periodic harvestig of seismic data for quality cotrol scrutiy. Cocludig remarks Although the above aalysis has produced some clearly delieated results, it must be remembered that both the categories of acquisitio systems ad the types of acquisitio programmes described above are by ecessity geeralizatios. I practice, there are a variety of differet features available across the rage of acquisitio systems that have i this paper, bee categorized together. Oe example is that some QC capable systems also allow harvestig of seismic data durig acquisitio, thus providig a higher degree of data quality cofidece tha those that do ot have this feature. Similarly, there are udoubtedly Pael 1: The term moder wireless lad acquisitio system is iteded to reflect the step chage i power cosumptio, size ad weight, ad performace relative to earlier radio based systems such as the ION RSR, Sercel Eagle, ad Fairfield BOX. These systems additioally utilized VHF radio bads that are o loger available for data commuicatios ad are extremely limited i badwidth. Figure 4 Radar map of operatioal priorities of acquisitio programme type. Impact o Proprietary Speculative Frack Moitorig Ease of deploymet Moderate Very high Very low Ease of operatio Moderate Very high Moderate Uptime Moderate Very high Very high Data quality cofidece Very high Low Very high Equipmet cofidece Very high Low Very high Portability Moderate Very high Very low Table 3 Summary of operatioal priorities of program types EAGE 99

6 first break volume 33, Jue 2015 Earth Sciece for Eergy ad Eviromet Refereces Pael 2: Crice, D. [2014] A cable-free lad seismic system that acquires data i real There are a umber of differet stadards for wireless etworkig techology icludig Bluetooth, Zigbee, WiFi ad WiMax. These stadards are geerally classified accordig to their badwidth ad rage. Persoal Area Networks are characterized by their relatively short rage a few tes of metres ad badwidth of the order of a few hudred kilobits per secod. Bluetooth ad Zigbee are examples of Persoal Area Networks. Wireless Local Area etworks, such as WiFi have a few hudred metres of rage (depedig o atea cofiguratio) ad badwidth i the tes of megabits per secod. time. First Break, 32 (1), Ellis, R. [2014] Curret cabled ad cable-free seismic acquisitio systems each have their ow advatages ad disadvatages is it possible to combie the two? First Break, 32 (1), Fairfield Nodal [2015] ZLad Operatio. Accessed at: Geospace Techologies [2013] Game Chagig Wireless Techology for or Marie Seismic Acquisitio. Accessed at: wp-cotet/uploads/2013/05/geospacewirelesseage2013.pdf. Heath, R. [2012] Cableless Cofusio. GeoExpro, May Heath, R. [2013] A Brave New World of Hybrid Recordig. GeoExpro, October Iova [2014] Hawk Product Brochure. Accessed at: com/images/stories/resources/hawk-brochure.pdf. Iova [2014] G3i Product Brochure. Accessed at: images/stories/resources/g3ihd-brochure.pdf. Lasley, M. [2013] Shiftig paradigms i lad data acquisitio. First Break, 31 (1), Schlumberger [2014] Uiq Product page. Accessed at: services/seismic/seismic_acquisitio/services/lad/techologies/uiq.aspx. Scott, L.M. [2012] AutoSeis - A Paradigm Shift i Seismic Data Acquisitio. Accessed at: Figure 5 Sercel lad systems rage of capabilities. acquisitio compaies udertakig speculative surveys who place a higher priority o data quality cofidece tha the geeralizatio described, ad who may prefer QC capable or eve real-time systems for this reaso. Nevertheless, the aalysis does show how the differeces i market requiremets have led to systems with differig capabilities beig offered. At Sercel, the UNITE wireless system is most commoly used as a QC Capable system but is able to operate fully blid, or as a moderate chael-cout Real-time system as well. The 508XT system was desiged with X-Tech architecture to icorporate features from both wireless ad cable techologies ad ca therefore operate over the whole rage of real-time ad QC capable fuctioalities, ad i additio ca be deployed for fully blid recordig if required. Of course, iteroperability betwee UNITE ad 508XT is desiged i. Ackowledgemets The author would like to thak Robi Ellis for his commets ad advice regardig the work preseted here, ad Sercel s marketig departmet for historic North America sales data EAGE CC00224-MA074 Geometrics.idd :08