# VSP->Xwell Interferometry

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x. x. B. B. x. x. ?. VSP->Xwell Interferometry. ?. 3x3 Classification Matrix. SSP. VSP. SWP. SSP. SSP. SSP. SSP. VSP. SSP. SWP. VSP. VSP. SSP. VSP. VSP. VSP. SWP. SSP. SWP. SWP. SWP. VSP. SWP. SWP. Xwell. Xwell. Xwell. SSP. Xwell. VSP. Xwell. x. x. x. - PowerPoint PPT PresentationTRANSCRIPT

<ul><li><p>VSP->Xwell Interferometry?</p></li><li><p>3x3 Classification MatrixSSPVSPSWPVSPSSPSWPSSPSSPSSPSSPVSPSWPVSPVSPVSPSWPSWPSWPVSPSWPSWPVSPSSPSSPXwellXwellXwellXwellSSPVSPXwell</p></li><li><p>VSP->Xwell Transform</p></li><li><p>Problem: Overburden+statics defocus VSP migrationRedatum sources below overburdenLocal VSP migrationSolution: VSP -> Xwell TransformMotivation</p></li><li><p>Key Idea of Local RTMsTheoryLocal VSP Greens function</p></li><li><p>Numerical Results1. Synthetic VSP (Jinahua Yu) 3. GOM VSP2. Synthetic VSP (Xiang Xu) </p></li><li><p>0 km2 km0 km3 kmWalkaway VSPSource number: 100Shot interval: 10 mReceiver number: 91Receiver interval: 10 mDepth of the first receiver: 950 mDepth of the last receiver: 1850 mTemporal interval: 0.001 s</p></li><li><p>Local VSP Migration ImageNo Overburden velocity neededNo need to know source location or excitation time</p></li><li><p>Limitations Rotated Pyramid vs PyramidLD</p></li><li><p>Numerical Results1. Synthetic VSP (Jinahua Yu) 3. GOM VSP2. Synthetic VSP (Xiang Xu) </p></li><li><p>Sigsbee P-wave Velocity Model0Depth (km)9.245001500m/s-12.512.5Offset (km)279 shots150 receivers</p></li><li><p>Local Reverse Time Migration Results4.69.2Depth (km)-33Offset (km)True modelMigration imagef</p></li><li><p>Numerical Results1. Synthetic VSP (Jinahua Yu) 3. GOM VSP2. Synthetic VSP (Xiang Xu) </p></li><li><p>Depth (m)Offset (m)4878018290GOM VSP Well and Source LocationSource @150 m offset2800 m3200 mSalt82 receivers</p></li><li><p>Velocity ProfileP-to-S ratio = 2.7 S WaveP WaveDepth (m)0450005000050002800 m3200 m SaltIncorrect velocity modelP-to-S ratio = 1.6 Velocity (m/s)Velocity (m/s)</p></li><li><p>Z-Component VSP DataDepth (m)Traveltime (s)265238871.23.0 SaltDirect PReflected PReverberations</p></li><li><p>X-Component VSP DataDepth (m)Traveltime (s)265238871.23.0 SaltDirect PReflected PReverberations Direct S</p></li><li><p>Local Reverse Time Migration Result(1)(2)(3)(1) specular zone, (2) diffraction zone, (3) unreliable zone3.3Depth (km)3.90100Offset (m)39receiversreflectivity</p></li><li><p>ConclusionsVSP->XWell transform alternative to VSP_>SWP and VSP->SSP transformsSource statics eliminated, no need to know src. Location or excitation timeLocal v(x) needed, overcomes defocusing due to overburdenNot battle-field tested, needs decon probably, weird resolution characteristics</p><p>This is the key difference between the . And the Any questions.This page looks like a content of a book, here I have the page number labled on each page. Not too long, My talk includes five parts. First, I will give my motivation and theory, and then I will present some numerical results and field data examples, at the end, comes the conclusion.</p><p>This page looks like a content of a book, here I have the page number labled on each page. Not too long, My talk includes five parts. First, I will give my motivation and theory, and then I will present some numerical results and field data examples, at the end, comes the conclusion.</p><p>This page looks like a content of a book, here I have the page number labled on each page. Not too long, My talk includes five parts. First, I will give my motivation and theory, and then I will present some numerical results and field data examples, at the end, comes the conclusion.</p><p>601/4 receiver are used, left side source are used, 279 sources.45.7 m source intervals and 150 vsp receivers with a 30 m intervals.This page looks like a content of a book, here I have the page number labled on each page. Not too long, My talk includes five parts. First, I will give my motivation and theory, and then I will present some numerical results and field data examples, at the end, comes the conclusion.</p><p>First, we look at the source and well geometry. This is a data collected by an anonymous company in Gulf of Mexico. The source is on a ship at about 150 m offset and receivers go throught the salt below the sea surface. The depth for the migration model is about 5000 m. The 150-m offset gather consists of 82 receivers from the depths of 2650 to 3890 m at 15.3 m intervals. Three component gathers are included.The left panel is the P wave velocity profile, which is generated from well information. Notice that the velocity above the salt is set to constant, which results migration with incorrect velocity model. The salt flank, show in profile with a upper boundary at 2800m depth and a lower boundary at 3200 depth. The P-to-S velocity ratio for the salt is 1.6 and the one for the sediments is 2.7. Then we get the s wave velocity profile at the right panel. The uppper part is out of the well control, we assume here constant velocity.This is the 150 offset X component. We can see clearly the direct p wave arrival, reflected P arrivals and strong alias (or called reverberation) This is the 150 offset Z component. We can see clearly the direct p wave arrival, direct S arrivals, reflected P arrivals and strong alias (or called reverberation) </p><p>Down: without direct arrivals up: early arrivals.</p></li></ul>

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