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- 1. 1. INTRODUCTION Geology is the science that deals with the history and structure of the earth and its life forms, especially as recorded in the rock record. A basic understanding of its concepts and processes is essential in the petroleum industry, for it is used to predict where oil accumulations might occur. It is the job of the petroleum geologist to use his/her knowledge to reconstruct the geologic history of an area to determine whether the formations are likely to contain petroleum reservoirs. It is also the job of the geologist to determine whether the recovery and production of these hydrocarbons will be commercially profitable. The physical characteristics of a reservoir, how petroleum originated and in what type of rock, what types of fluids exist in the reservoir, how hydrocarbons become trapped, and basic well log analysis are some of the concepts vital to the production and recovery efforts of any exploration or energy service company. 2. INTRODUCTION TO GEOLOGICAL MAP Subsurface geological maps are perhaps the most important vehicle used to explore for un discovered hydrocarbons and to develop proved hydrocarbon reservoir. However, aspect of petroleum exploration and exploration .as afield developed from its initial discovery a large volume of well log seismic and production data are obtained with these data the accuracy of the subsurface interpretation is improved through time. 2.1. STURCTURE CONTOUR MAP: A structure contour is the trace of a horizontal line on a surface (e.g., on a formation top or a fault). The dip direction of the surface is perpendicular to the contour lines and the dip amount is proportional to the spacing between the contours. Structure contours provide an effective method for representing the three-dimensional form of a surface in two dimensions. 2.2. ISOPACH MAPS: An isopach map is used to show thickness trends from measurements at isolated points. An isopach map can be interpreted as a paleotopographic map if the upper surface of the unit was close to horizontal at the end of deposition. If the paleotopography was controlled by structure, then it can be considered to be a paleostructure map. The thickness variations represent the structure at the base of the unit as it was at the end of deposition of the unit. The trend of increased thickness down the center of the map in could imply a filled paleovalle.
- 2. 3. WELL LOCATION MAP: Well location map determines the coordinates (X-Y) in the field by using the given data in table (1-1): Table (1-1) Well X Y Top (m) Bottom (m) Net Pay B-123 812065.6325 640147.5096 1130 1250 120 B-122 811933.8902 640904.2146 1195 1275 80 B-124 812038.9021 640632.1839 1158.5 1229.4 70.9 B-125 811949.1647 640848.659 1090 1178 88 B-126 812048.4487 641337.1648 1344 1409 65 B-127 810719.5704 642651.341 1247.96 1335.96 88 B-128 811828.8783 641009.5785 1038.76 1109.69 70.93 B-129 812008.3532 640718.3908 1062.5 1108.5 46 Figure (1-1)
- 3. Figure (1-3) Figure (1-2) Figure (1-4)
- 4. Original oil in place calculation from isopach map: From pay (isopach) maps: Table (1-2) The trapezoid volume formula: If ratio 𝐴𝑛+1 𝐴𝑛 ˃0.5 used the trapezoid volume formula Δvb = h/2 (An+An+1) The pyramidal volume formula: If ratio 𝐴𝑛+1 𝐴𝑛 ˂0.5 used the pyramidal formula: √𝐴𝑛𝐴𝑛+1) + n+1 +A n = h/3 (A b v Δ Number of zone Contour Value Thikns (m) Area (m) Ratio (A1/A2) Method Δv (m3) A0 110 5 3353898.69 0 A1 105 5 3322367.2 1.00949067 T 16690665 A2 100 5 3170364.82 1.047944759 T 16231830 A3 95 5 2968126.18 1.068136808 T 15346227 A4 90 5 2751715.68 1.078645659 T 14299605 A5 85 5 2385777.8 1.153383053 T 12843734 A6 80 5 1640670.66 1.454147901 T 10066121 A7 75 5 919410.321 1.784481451 T 6400202.5 A8 70 5 281769.893 3.262982818 T 3002950.5 A9 65 5 17212.2246 16.37033561 T 747455.29 A10 60 5 9579.675 1.796744107 T 66979.749 A11 55 5 3510.07068 2.729197183 T 32724.364 A12 50 5 116.10184 30.23268777 T 9065.4313 A13 45 0.75908646 0 0 290.2546
- 5. ———————————————— Grid Volume Computations ———————————————— Sun Dec 25 10:28:03 2022 Upper Surface Grid File Name: D:PROJECTNew foldernew bottom.grd Grid Size: 100 rows x 54 columns X Minimum: 810719.5704 X Maximum: 812065.6325 X Spacing: 25.397398113207 Y Minimum: 640147.5095 Y Maximum: 642651.341 Y Spacing: 25.291227272727 Z Minimum: 1140 Z Maximum: 1260 Lower Surface Grid File Name: D:PROJECTNew foldernew top.grd Grid Size: 100 rows x 54 columns X Minimum: 810719.5704 X Maximum: 812065.6325 X Spacing: 25.397398113207 Y Minimum: 640147.5095 Y Maximum: 642651.341 Y Spacing: 25.291227272727 Z Minimum: 1140 Z Maximum: 1260 Volumes Z Scale Factor: 1
- 6. Total Volumes by: Trapezoidal Rule: 95841444.032121 Simpson's Rule: 95845267.974932 Simpson's 3/8 Rule: 95849666.866233 Cut & Fill Volumes Positive Volume [Cut]: 95846498.948877 Negative Volume [Fill]: 0 Net Volume [Cut-Fill]: 95846498.948877 Areas Planar Areas Positive Planar Area [Cut]: 3370312.6869361 Negative Planar Area [Fill]: 0 NoData Planar Area: 0 Total Planar Area: 3370312.6869361 Surface Areas Positive Surface Area [Cut]: 3418498.085525 Negative Surface Area [Fill]: 0