Nzira yeCDP yeKutenderera kweMafashamo muKutsvaga kweHydrocarbon
Kutsvaga Hydrocarbon (oiri negasi) kunoda ruzivo rwakadzama, rwakarurama, uye rwakanyatsogadzirwa pasi pevhu. Imwe yenzira dzinonyanya kushandiswa pakuongorora izvi ndeye reflection seismic, nekuti inogona kuratidza chimiro chepasi pevhu uye stratigraphy muzvikamu zviviri (2D) uye zvitatu (3D). Mu reflection seismic yemazuva ano, pfungwa yeCDP (Common Depth Point)—inowanzonzi CMP (Common Midpoint)—ndiyo hwaro hukuru mukuwana nekugadzira data kuti kunatsiridze mhando yemifananidzo yepasi pevhu. Nzira yeCDP seismic yakaratidza kushanda zvakanaka mukuona misungo, kugadzira mapa ereservoir layers, kuona ukobvu hwematombo uye kuramba kuripo, uye kuderedza kusanzwisisika kwetsananguro.
Pfungwa Dzekutanga dzeKufungisisa Kwepasi
Nzira yekutarisa kwepasi inoshanda nepfungwa iri nyore: simba (senge vibroseis panyika kana pfuti yemhepo mugungwa) rinoburitsa mafungu epasi pevhu. Mafungu aya anopararira kuburikidza nematombo, uye rimwe resimba rawo rinoonekwa kana asangana nemuganhu uri pakati pezvikamu zvine acoustic impedance contrast (chibereko chekuwanda kwematombo uye kumhanya kwemafungu). Mafungu aya anoonekwa anotorwa ne receiver sensor (geophone panyika kana hydrophone mugungwa) uye anonyorwa sechiratidzo nekufamba kwenguva. Iyi data isina kujeka inozogadziriswa kuita chikamu che seismic chinoratidza subsurface reflectors.
Zvisinei, dambudziko guru rekudengenyeka kwenyika nderekuti chiratidzo chinogamuchirwa hachingokanganisirwi nekutanga kuratidzwa, asiwo neruzha, mafungu epamusoro, diffraction, multiples, kusiyana kwenzvimbo, uye mhedzisiro ye geometry yekuyera. Apa ndipo panonyanya kukosha nzira yeCDP, sezvo ichivimba nekuongororwa kwakadzokororwa panzvimbo imwecheteyo pasi pevhu kuti ivandudze chiyero chesignal-to-noise uye kuvandudza kusarudzwa kwe geometry ye reflector.
Tsanangudzo uye Nheyo dzeCDP Method
Common Depth Point (CDP) inzira yekuwana nekugadzirisa seismic apo ma "multiple source-receiver" maviri anonyora kudzokorora kubva panzvimbo imwechete yakadzika pasi pepamusoro. Mukuita, magadzirirwo e "seismic" anogadzirwa kuitira kuti ma "traces" akawanda ave ne "common midpoint" (CMP), iyo inofungidzirwa kuti inomiririra nzvimbo imwechete yekuratidzira ye "horizontal" kana "like" sloped. Muunganidzwa we "traces" dzakaunganidzwa paCDP imwe chete unonzi "CDP gather".
Chakanakira kuunganidzwa kweCDP kudzokororwa kwedata: kudzokororwa kubva kuhorizon imwe chete kunonyorwa kakawanda pamatanho akasiyana (nzvimbo dzinobva kune source-receiver). Kudzokororwa uku kunogonesa matanho akakosha ekugadzirisa akadai sekuongorora velocity, Normal Moveout (NMO) correction, uye stacking. Pakupedzisira, kuisa traces dzakawanda muCDP imwe chete kunoratidza kudzokororwa kwakasimba uye kuderedza ruzha rusina kurongeka.
Kuwanikwa kweData reSeismic neCDP Concept
Mukuwana 2D seismic, masosi anoiswa panzvimbo dzakatarwa dziri munzira, nepo mareceiver achiiswa mu array ine nzvimbo yakarongeka. Nguva imwe neimwe kana sosi yapfurwa, chiratidzo chinonyorwa nemareceiver akawanda, zvichigadzira "shot gather" imwe chete. Nekufambisa zvishoma nezvishoma sosi iri munzira (roll-along), mapeya akasiyana ereceiver achagadzira midpoint imwe chete, nokudaro achigadzira CDP coverage yakakwana.
Mu3D seismic, pfungwa yacho yakafanana asi yakatambanudzirwa kune nzvimbo dzine mativi maviri (mukati nepakati). Matsime neanogamuchira akarongwa mu grid geometry kuitira kuti bhini rega rega reCDP (rinowanzonzi bhini reCMP) rive nezviratidzo zvakasiyana-siyana zvine azimuth dzakasiyana uye offsets. Kufukidza kwakanyanya—kunoratidzwa semapete—kunobatsira pakuvandudza kunaka kwedata, kuderedza mhedzisiro yeruzha, uye kuwedzera kuvimbika kwehunhu hwe seismic.
Zvimwe zvinhu zvinokanganisa kunaka kweCDP zvinosanganisira:
1. Chikamu cheCDP (saizi yebhini): saizi yebhini yakakura zvakanyanya inogona kuvharidzira mativi echivako, nepo diki zvakanyanya inogona kuderedza kupetwa kwebhini rega rega.
2. Kuvhara mapeta: kana mapeta akakura, kazhinji mapeta acho anobuda zvakanaka (kusvika pamuganho wakati).
3. Kudzikisa kwakanyanya: kunodiwa pakuongororwa kwekukurumidza uye AVO (Amplitude Versus Offset), asi kudzikisa kwakanyanya kunogonawo kuwedzera kukanganiswa uye ruzha.
4. Kugoverwa kweAzimuth (3D): kwakakosha pakufungidzira zvivakwa zvakaoma zvakaita sezvikanganiso uye madome emunyu.
Matanho Ekugadzirisa Data reCDP
Kugadziriswa kwekudengenyeka kwenyika kwakavakirwa paCDP kunowanzo sanganisira matanho akakosha anotevera.
1. Kuronga kusvika paCDP Gather
Data rekutanga muchimiro chekuunganidza pfuti rinorongwazve kuita maCDP gathers. Nekuronga uku, CDP yega yega ine zviratidzo zvinonyora kuratidzwa kubva panzvimbo imwechete yepasi pevhu (zvingangove zvakanaka).
2. Kugadzirisa Kusamira Uye Kugadzirisa Pedyo Nepamusoro
Panyika, zvikamu zvakasiyana-siyana zvepedyo nepamusoro zvinowanzounza kunonoka kwenguva kwakasiyana. Kugadzirisa kwakasimba kunovavarira kuenzanisa nguva kuitira kuti kuratidzwa kubva pahorizon imwe chete kuenderane nezviratidzo zviri muCDP.
3. Kuongorora Kumhanya
Kumhanya kwemafungu ekudengenyeka kwenyika mudombo ndiko kunosarudza chimiro chekufamba kwemhepo muboka reCDP. Kuongorora kumhanya kunoitwa uchishandisa kufanana kana kubatana kuti uwane kumhanya kunogadzira kurongeka kwakanakisa kwekuratidzira. Kumhanya uku kwakakosha pakugadzirisa nekufamba kweNMO.
4. Kugadziriswa kweNMO (Normal Moveout)
Nekuti mareceiver ane ma offsets akasiyana, nguva yekufamba kwe reflection ichave yakareba pa ma offsets makuru. Kugadziriswa kweNMO kunobvisa musiyano wenguva iyi, zvichikonzera parallel reflections. Kubudirira kweNMO kunoenderana zvakanyanya nekumhanya kwakakodzera.
5. Kuunganidza zvinhu
Kana maratidziro arongeka, maronda ari muboka reCDP anounganidzwa. Kuisa maronda kunovandudza chiyero chesignal-to-noise nekuti masaini ekuratidzira akabatana anosimbisana, nepo ruzha rusingatarisirwi runowanzo bvisana. Mugumisiro wacho i "stack" trace imwe chete yeCDP yega yega, iyo yakachena uye iri nyore kududzira.
6. Kutama
Kutama kunofambisa simba rekuratidzira kunzvimbo chaiyo yejometri, kunyanya kune ma reflector akatsveyama, akakanganisa, uye anochinja-chinja. Pasina kutama, zvikamu zvekudengenyeka kwenyika zvinogona kuisa ma reflector panzvimbo isiriyo. Kutama kunogona kuitwa munzvimbo yenguva kana kudzika, uye kunaka kwayo kunoenderana nemuenzaniso wekukurumidza.
Mabhenefiti eCDP Method yeKutsvaga Hydrocarbon
Nzira yeCDP yekutinhira kwepasi ine simba guru pakutsvaga mahydrocarbon nekuti:
1. Kuvandudza mhando yemifananidzo iri pasi pevhu
Nekurongedza zvinhu, kuratidzwa kwekutanga kunova pachena kuitira kuti muganhu wechinangwa ugone kurongeka zvakaringana.
2. Inotsigira mepu yemaitiro emusungo
Magadzirirwo emuchina, zvikanganiso, kutenderera, uye stratigraphic zvinogona kuonekwa zviri nani mushure mekufamba kwemhepo kwakavakirwa pakufamba kwemhepo kubva kuCDP.
3. Kuvandudza kuvimbika kwekududzira stratigraphic
Kuenderera mberi kweReflector, kuguma kwelayer (onlap, downlap, truncation), uye sediment geometry zvinobatsira kunzwisisa peturu.
4. Inovhura nzira yekuongorora kwakawedzerwa (AVO uye hunhu)
Data reCDP pre-stack rinoita kuti kuongororwa kweAVO kuonekwe kuti mvura iri mudura iratidzwe sei, pamwe nekuchinja kweimpedance kuti ionekwe senzvimbo ine mvura.
5. Kushanda zvakanaka kwesarudzo dzekuchera
Ruzivo rwakanyatsojeka nezvemaumbirwo uye kudzika kwenzvimbo yetsime runoderedza njodzi yenzvimbo yacho uye runobatsira pakuongorora huwandu hwenzvimbo yacho.
Zvipingamupinyi Nezvinetso
Pasinei nezvakanakira zvayo, nzira yeCDP ine miganhu. Pfungwa ye "same reflection point" inoshanda zvakanyanya kune ma "horizontal reflectors" uye zviri nyore kushandisa. Muzvivakwa zvakaoma—semuenzaniso, nzvimbo dzine materu akareba, zvikanganiso zvakasimba, kana kumhanya kwemativi kunochinja nekukurumidza—CDP gather inogona kuva nesimba kubva kunzvimbo dzakasiyana dzereflection (non-hyperbolic moveout), zvichiita kuti NMO ne stacking zvisashande zvakanaka. Uyezve, zviitiko zvakawanda uye ruzha rwakabatana zvinogona kuoneka kunyangwe stacking ichiitwa. Nokudaro, mamwe maitiro akadai se demultiple, anisotropy correction, uye pre-stack migration zvinodiwa mune zvimwe zviitiko.
Penutup
Nzira yeCDP seismic ndiyo nheyo huru yekuongorora kwepasi pemvura kwemazuva ano pakutsvaga mahydrocarbon. Nekushandisa zviyero zvinodzokororwa panzvimbo imwe chete yepasi pemvura, CDP inogonesa kuvandudzwa kwekuongorora kwekukurumidza, kugadzirisa kufamba, kurongedza kuti kuvandudza chiyero chesignal-to-noise, uye kufamba, zvichikonzera nzvimbo dzakanyatsojeka dzekuratidzira. Mhedzisiro yacho imifananidzo yakajeka uye yakavimbika yepasi pemvura yekuona misungo, kugadzira mapombi emvura, uye kuderedza njodzi dzekutsvaga. Sezvo tekinoroji ye3D acquisition, processing yemakombiyuta, uye nzira dzedudziro dzakavakirwa pahunhu dzichifambira mberi, nzira yeCDP inoramba yakakosha sehwaro hwekubvisa ruzivo rwe geological kubva kudata re seismic.
