Question 1 Part 1 In a two horizontal layered model the velocities of both layers and...

  

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Question 1 Part 1 In a two horizontal layered model the velocities of both layers and the thickness of the first layer are given in part 1 in the excel sheet: Answer the following Questions Find the critical distance (3 points) At which distance of the closest geophone (offset) should the source be located so that the geophones will record only refracted waves (no direct waves)? (3 points) ➤Which type of seismic waves will be recorded first (first arrival) at a geophone which is at x m (check the excel table) from source? Justify your answer? (4 points) Im PETROLEUM GESCIENCES & REMOTE SENSING My EXPLORATION GEOPHYSICS I ASSIGNMENT 02 Question 1 Part 2 Based on the time of first arrivals given in the excel sheet (Part B), and assuming that we have only 2 horizontal layers, answer the following questions: >The velocity of the seismic waves in the first layer? (3 points). > The velocity of the seismic waves in the second layer (3 points) The thickness of the first layer (4 points) PART A V1 (m/s) V2 (m/s) hl (m) x (m) PART B a/a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1000 2300 10 31 Distance from Source (m) 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time of first arrivals (ms) 5.0 10.0 15.0 20.0 25.0 30.0 33.2 35.4 37.6 39.7 41.9 44.1 46.3 48.4 50.6 52.8 55.0 57.1 59.3 61.5 63.7 65.8 68.0 70.2 Question 1 Table FROM Excel sheet Part a vd (0/1) v20m/s) bi im ximi Part B a/a 1 2 3 4 5 6 7 8 9 10 11 12 13 1000 2500 10 30 Distance from source (m) 5 10 15 20 25 30 35 40 45 50 55 60 65 Vadina First Arrivals (ms) 5 10.0 20.0 28.9 32.2 35.5 38.9 42.2 45.5 48.9 52.2 55.5 58.9 62.2 Question 1 Find the critical distance Source Reflected ray A Offset Critical reflection Directa h,tan(i) Critically retractedray R Head wave Geophones & h₂ cos(ic) Cicary reacted rays X,=2h, tan(i) z1=10m i-sin-¹(v1/v2) V1=1000m/s V2=2500m/s Part a v (m/10 v2 in/a h10m bond 1000 2500 10 30 x=2*10m*tan(23.58⁰°) => x=8.73m Question 1 At which distance of the closest geophone (offset) should the source be located so that the geophones will record only refracted waves (no direct waves)? Source ected Offset Critical reflection Drect ray h,tan(i) ASSIGNMENT 02 Critically retracted ray R Head wave Geophones cos(le) Cicary reacted rays x > xc = 2h₁ V₁ + V₂ V₂-V₁ z1=10m al=1000m/s a2=2500m/s x = 2*10m*, Part a v (m/ v2 (m/v) hm 1000 2500 10 30 =>x>x=30.55m 2500m/s+1000m/s 2500m/s-1000m/s Part v1 m/ √2 (M/ NE (m Part B a/a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 THE 2012020000 1000 2500 10 30 Distance from (m) 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 source First Arrivals (ms) 10.0 20.0 (28.9) 32.2 35.5 38.9 42.2 45.5 48.9 52.2 55.5 58.9 62.2 65.5 68.9 72.2 75.5 78.9 82.2 85.5 88.9 92.2 95.5 (989) ASSIG SENSING Question2 Time of first arrivals (ms) 02 100 90 2828892 80 70 60 50 40 30 20 10 1/V₂ IN₁ 0 0 10 20 30 40 50 60 70 80 90 100 110 120 • Απευθείας Mu Distance from source (m) V₁= Ax/At = (10m-0m)/(20ms-0ms) = 500m/s V₂= Ax/At = (120m-15m) / (98.9ms-28.9ms) => V₂= 1500 m/s Part VI V 12/ htm) wom Part B a/a 1 2 3 4 5 6 7 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 2012020000 1000 2500 10 30 Distance from source (m) 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 First Arrivals (ms) 10.0 20.0 (289) 32.2 35.5 38.9 42 2 45.5 48.9 52.2 55.5 58.9 62.2 65.5 68.9 72.2 75.5 78.9 82.2 85.5 88.9 92.2 95.5 (989) ASSIGNMENT 02 SENSING Question2 T₂ 18.9 ms. Time of first arrivals (ms) 888288288 100 90 80 70 60 50 40 30 20 10 1/V₂ INT 0 0 10 20 30 40 50 60 70 80 90 100 110 120 Distance from source (m) V₁-500m/s V₂=1500m/s i= sin ¹(a,/a₂) Ancutio * Μετωπικά Question 1 Part 1 In a two horizontal layered model the velocities of both layers and the thickness of the first layer are given in part 1 in the excel sheet: Answer the following Questions Find the critical distance (3 points) At which distance of the closest geophone (offset) should the source be located so that the geophones will record only refracted waves (no direct waves)? (3 points) ➤Which type of seismic waves will be recorded first (first arrival) at a geophone which is at x m (check the excel table) from source? Justify your answer? (4 points) Im PETROLEUM GESCIENCES & REMOTE SENSING My EXPLORATION GEOPHYSICS I ASSIGNMENT 02 Question 1 Part 2 Based on the time of first arrivals given in the excel sheet (Part B), and assuming that we have only 2 horizontal layers, answer the following questions: >The velocity of the seismic waves in the first layer? (3 points). > The velocity of the seismic waves in the second layer (3 points) The thickness of the first layer (4 points) PART A V1 (m/s) V2 (m/s) hl (m) x (m) PART B a/a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 1000 2300 10 31 Distance from Source (m) 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 Time of first arrivals (ms) 5.0 10.0 15.0 20.0 25.0 30.0 33.2 35.4 37.6 39.7 41.9 44.1 46.3 48.4 50.6 52.8 55.0 57.1 59.3 61.5 63.7 65.8 68.0 70.2 Question 1 Table FROM Excel sheet Part a vd (0/1) v20m/s) bi im ximi Part B a/a 1 2 3 4 5 6 7 8 9 10 11 12 13 1000 2500 10 30 Distance from source (m) 5 10 15 20 25 30 35 40 45 50 55 60 65 Vadina First Arrivals (ms) 5 10.0 20.0 28.9 32.2 35.5 38.9 42.2 45.5 48.9 52.2 55.5 58.9 62.2 Question 1 Find the critical distance Source Reflected ray A Offset Critical reflection Directa h,tan(i) Critically retractedray R Head wave Geophones & h₂ cos(ic) Cicary reacted rays X,=2h, tan(i) z1=10m i-sin-¹(v1/v2) V1=1000m/s V2=2500m/s Part a v (m/10 v2 in/a h10m bond 1000 2500 10 30 x=2*10m*tan(23.58⁰°) => x=8.73m Question 1 At which distance of the closest geophone (offset) should the source be located so that the geophones will record only refracted waves (no direct waves)? Source ected Offset Critical reflection Drect ray h,tan(i) ASSIGNMENT 02 Critically retracted ray R Head wave Geophones cos(le) Cicary reacted rays x > xc = 2h₁ V₁ + V₂ V₂-V₁ z1=10m al=1000m/s a2=2500m/s x = 2*10m*, Part a v (m/ v2 (m/v) hm 1000 2500 10 30 =>x>x=30.55m 2500m/s+1000m/s 2500m/s-1000m/s Part v1 m/ √2 (M/ NE (m Part B a/a 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 THE 2012020000 1000 2500 10 30 Distance from (m) 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 source First Arrivals (ms) 10.0 20.0 (28.9) 32.2 35.5 38.9 42.2 45.5 48.9 52.2 55.5 58.9 62.2 65.5 68.9 72.2 75.5 78.9 82.2 85.5 88.9 92.2 95.5 (989) ASSIG SENSING Question2 Time of first arrivals (ms) 02 100 90 2828892 80 70 60 50 40 30 20 10 1/V₂ IN₁ 0 0 10 20 30 40 50 60 70 80 90 100 110 120 • Απευθείας Mu Distance from source (m) V₁= Ax/At = (10m-0m)/(20ms-0ms) = 500m/s V₂= Ax/At = (120m-15m) / (98.9ms-28.9ms) => V₂= 1500 m/s Part VI V 12/ htm) wom Part B a/a 1 2 3 4 5 6 7 8 9 10 12 13 14 15 16 17 18 19 20 21 22 23 24 2012020000 1000 2500 10 30 Distance from source (m) 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 First Arrivals (ms) 10.0 20.0 (289) 32.2 35.5 38.9 42 2 45.5 48.9 52.2 55.5 58.9 62.2 65.5 68.9 72.2 75.5 78.9 82.2 85.5 88.9 92.2 95.5 (989) ASSIGNMENT 02 SENSING Question2 T₂ 18.9 ms. Time of first arrivals (ms) 888288288 100 90 80 70 60 50 40 30 20 10 1/V₂ INT 0 0 10 20 30 40 50 60 70 80 90 100 110 120 Distance from source (m) V₁-500m/s V₂=1500m/s i= sin ¹(a,/a₂) Ancutio * Μετωπικά