Petroleum Engineering Assignment 1 Due Date: Date: 15th 15th of April April 2013 2013
Lateef Akanji (Ph.D., D.I.C.) Petroleum and Gas Engineering University of Salford
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October 14, 2012
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Well Test Equations
∆P skin skin = (P wf wf )measured − (P wf wf )calculated ∆P skin skin s = qµB 2πκh
J measured P − P wf ∆P skin measured wf + ∆P skin = J calculated P − P wf calculated wf φµctr 2 −948 70..6µB 70 948φµc ∆P = − q 1E i kh κt ∆G = V uLco∆P ρo
+ (q (q 2 − q 1)E i
φµc r 948φµc 948
−
t
κ (t − t 1 )
C = V uLco N p t p = q ∆P m = Cycle κt p t pDA = φµctA P DMBH 3026(P ∗ −P ) P )/m D MBH = 2.3026(P qµB κ = 0.183 mh qµB κ = 162. 162.6 mh (P 1hr − P wf κ wf ) − log s = 1.1513 + 3. 3.2255 2 m φµctrw (P i − P wf κ wf (t1 )) s = −1.1513 + logt1 + log + 0. 0.35173 2 m φµctrw
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Well Test Equations
qµB ∆P κ= 2πh∆P D
2
tL ∆tc
F ig
2
tL ∆tc
qµB (P D )M κ= 2πh ∆P M κ tM φct = 2 µr tD
2 rD
M
or in field unit
qµB ∆P κ = 141.2 h∆P 2
tL ∆tc
D
tL ∆tc
F ig
2
qµB (P D )M h ∆P M 2.64e 4κ tM φct = tD µr2 κ = 141.2
−
2 rD
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M
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Petroleum Geology :Geologic Features
Figure 1: Geologic feature
Question 1
1. Determine the relative ages in Figure 1 2. Name the features marked A, B, C and D 3. Describe the sequence of events that resulted in the formation of the geological features observed in Figure 1
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Page 3 of 25
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Petroleum Geology :Geological Map Interpretation
Question 1
Figure 2: Geological map
Question 2
1. Identify the rock types in the area shown Figure 2 2. Determine the relative ages of the rocks 3. Name the geological structures that you are able to identify (in the case of folds, draw their axes) 4. Describe the geological history of the area
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Exploration : Exploration techniques
Question 2
Question 3
1. State and define the principle methods of exploration and reservoir prediction 2. What are the two methods commonly used in seismic prospecting? (a) Which is most often used? (b) Which gives the most information? 3. Describe hydrocarbon indicators on a seismic section 4. What sources of energy are most often used in seismic exploration? 5. What are the principal uses of seismic data
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Petroleum Geology (Case-studies GP1 ):UK North Sea
Question 3
Question 4
1. Using a simplified map, describe the major subdivisions and brief geological history of the North Sea 2. Describe the major distributions of oil and gas fields in the Southern North Sea (SNS) basin and adjacent onshore UK areas 3. Using a simplified stratigraphic column describe the oil and gas fields found in the Northern North Sea (NNS) 4. Describe the diffferent kinds of sedimentary rock and fluid types found in the North Sea and relate them to the depositional processes that led to their formation 5. Discuss the historical oil and gas production profile from the UK North Sea and the future direction
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Page 6 of 25
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Petroleum Geology (Case-studies GP2 ):Nigerian Niger Delta
Question 4
Question 5
1. Using a simplified map, describe the major subdivisions and brief geological history of the Nigerian Niger Delta basin 2. Describe the major distributions of oil and gas fields in the Niger Delta basin 3. Using a simplified stratigraphic column describe the oil and gas fields found in the Nigerian Niger Delta basin 4. Describe the diffferent kinds of sedimentary rock and fluid types found in the Niger Delta and relate them to the depositional processes that led to their formation 5. Discuss the historical oil and gas production profile from the Niger Delta and the potentials for future exploitation
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Page 7 of 25
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Petroleum Geology (Case-studies GP3 ):Arabian Gulf
Question 5
Question 6
1. Using a simplified map, describe the major subdivisions and brief geological history of the Arabian Gulf basin 2. Describe the major distributions of oil and gas fields the Arabian Gulf basin 3. Using a simplified stratigraphic column describe the oil and gas fields found in the Arabian Gulf basin 4. Describe the diffferent kinds of sedimentary rock and fluid types found in the Arabian Gulf and relate them to the depositional processes that led to their formation 5. Discuss the historical oil and gas production profile from the Arabian Gulf and the potentials for future exploitation
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Page 8 of 25
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Petroleum Geology (Case-studies GP4 ):Gulf of Mexico Basin
Question 6
Question 7
1. Using a simplified map, describe the major subdivisions and brief geological history of the Gulf of Mexico basin 2. Describe the major distributions of oil and gas fields in the Gulf of Mexico 3. Using a simplified stratigraphic column describe the oil and gas fields found in the Gulf of Mexico 4. Describe the diffferent kinds of sedimentary rock and fluid types found in the Gulf of Mexico and relate them to the depositional processes that led to their formation 5. Discuss the historical oil and gas production profile from the Gulf of Mexico and the potentials for future exploitation
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Drilling (Ass ): Drilling Engineering
Question 7
Question 8
1. The target and the rig coordinates of a well are given in Table 1. Determine the relative position of the rig and target (a) rectangular coordinates (b) polar coordinates Table 1: Coordinates of rig and target
N S (meters) EW (meters)
T arg et
Rig
964 −144
1334 653
2. Using Figure 3 and the information provided in Table 2, design a build and hold trajectory Table 2: Build and hold trajectory design Vertical depth Horizontal displacement Kick-off depth Build rate
3, 218.688 meters [10, 560 f t.] 1 , 333.5 meters [4, 375 f t.] 457.2 meters [1, 500 f t.] o 2 per 30.48 meters [2o per 100f t.]
3. From your design, determine the following: (a) radius of curvature of the build section (b) hold angle (c) measured depth (M D) at start of Hold section (M Dhold ) (d) measured depth (M D) at total depth (M DT D )
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Drilling (Ass ): Drilling Engineering
Question 8
Figure 3: A build and hold trajectory
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Production & Well-Test :Well-Test Objectives
Question 8
Question 9
1. Explain the following production related terms, stating all related equations (a) Productivity index (b) Vertical lift performance (c) Inflow performance relationship (d) Gas reservoir deliverability 2. Describe the following well-test methods and state the main ob jectives of conducting each (a) Injectivity test (b) Fall-off test (c) Interference test (d) Drill-stem test (e) Pulse test
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Production & Well-Test : Pressure Drawdown
Question 9
Question 10
Table 3 is a pressure drawdown test data from a well in an undersaturated reservoir with the following properties:
P i = 20.7 M P a[3002.3 psi] Boi = 1.32 −
µo = 9.2 × 10
3
P a − s[9.2 cp]
h = 21 m[68.9f t.] φ = 0.17 S wi = 0.26 ct = 1.2 × 10
−
9
P a 1[8.27 × 10 61/psi] −
−
rw = 0.1m [0.328 f t.] q =
−
17.2 m3/d[108.2 bbl/d]
1. Plot P wf versus time on a semilog coordinate sheet (Sheet A) 2. From your plot and using appropriate equations, determine: (a) the gradient, m (b) the pressure at t = 10 hrs (c) the permeability, κ (d) the skin effect, s (e) whether the system is damaged or stimulated
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Production & Well-Test : Pressure Drawdown
Question 10
Table 3: Pressure drawdown test data Time(hours)
32 43 53 64 72 81 110
P wf
(M P a) 18.41 18.38 18.35 18.32 18.30 18.29 18.25
Figure 4: Sheet A
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Production & Well-Test : Build-up & reservoir pressure
Question 10
Question 11
1. Figure 5 is a pressure build-up curve from a reservoir with a limited drainage area. (a) Determine the production time t p (b) Estimate the slope, m (c) From the graph, estimate the P ws (1hour) and the corresponding P wf (d) Why is the P ws (1hour) different from the corresponding P wf ?
Figure 5: Pressure build-up curve with a limited drainage area
2. Using the Matthews-Brons-Hazenbroek (MBH) method, determine the mean pressure of the drainage area of a well in the above reservoir which is placed at the center of a square with a surface A = 0.42 × 106 m2 (103.8 acre). Use Figure 6 and the following additional data. Question 11 continued on next page. . .
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Production & Well-Test : Build-up & reservoir pressure Question 11 (continued)
Figure 6: MBH dimensionless pressure for different well locations in a square drainage area (after MatthewsBrons-Hazenbroek)
Additional pressure build-up data N p = 21409 m3 [134648bbl], cumulative production q = 38.3 m3/d [241bbl/d], production rate before shut-in Boi = 1.52 (rb/stb) P i = 20.7 M P a [3002.3 psi] µo = 9.2 × 10
3
−
Pa-s [9.2 cp]
h = 21 m [68.9 ft] φ = 0.17 [ ] S wi = 0.25 [ ] ct = 1.2 × 10 9P a −
−
1
[8.27 × 10 61/psi] −
rw = 0.1 m [0.328 f t] Question 11 continued on next page. . .
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Page 16 of 25
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Production & Well-Test : Interference and Diagnostics Question 11 (continued)
Question 12
1. During an interference test, water was injected in the active well for 22 days. The distance to the observation well is 112.4 m [368.8f t]. The measured pressure changes are drawn on a transparent sheet versus t (hour), and matched by parallel shifting in Figure 7 with the type curve. In the match point: (a) tM = 100hours 2 (b) (tD /rD )M = 50
(c) ∆P M = 105 Pa [= 14.5 psi] (d) P D M = 0.8
Additional data q = 300 m3/d [= 1887bbl/d] µ = 0.82 × 10
3
−
Pa-s [0.82cp]
Bw = 1.0 h = 12 m [39.4f t] r = 112.4 m [368.8f t]
(a) Determine the permeability, κ and (b) φct
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Page 17 of 25
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Production & Well-Test : Interference and Diagnostics
Question 12
Figure 7: Illustration of type curve matching for an interference test
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Production & Well-Test : Interference and Diagnostics
Question 12
Question 13
Figure 8 is a well test interpretation models for wells near a single fault, channel system and wedge systems. The corresponding pressure change and derivative plots are also shown on a log-log plot. Analyze each of the plots.
Figure 8: Well test interpretation models
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Page 19 of 25
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Reservoir Performance : Reservoir Engineering
Question 13
Question 14
Consider a reservoir that is shaped like a circular disk, 10 m thick, and with a 5 km radius in the horizontal plane. The mean porosity of the reservoir is 15%, the water saturation is 0.3, and the oil saturation is 0.7. 1. Ignoring the expansion of the oil that would occur when it is produced from the reservoir, how many barrels of oil are in this reservoir? (One barrel = 0.1589 m3). 2. If the density of the oil is 900 kg/m3, how much oil (in kg) is contained in the reservoir? Question 15
With the aid of annotated phase envelope diagrams, describe the following 1. cricondenbar and cricondentherm 2. retrograde condensation, dry-gas and wet gas 3. light, intermediate and heavy crude systems Question 16
Given the gas production data shown in Table 4. Determine: 1. the total volume (at standard conditions) of gas initially in place (GIIP) Question 16 continued on next page. . .
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Reservoir Performance : Reservoir Engineering
Question 16 (continued)
Table 4: Data from a gas reservoir Pressure(M P a)
Z
G p (108 m3 )
25 24 23 22 21
0.85 0.86 0.87 0.88 0.89
0 6.09 11.8 17.1 23.1
2. the volume of gas (G p) that will be produced at the abandonment pressure of 3 M P a when Z = 0.95 3. Explain why the abandonment pressure is not 0.1 M P a (1 atm)
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Reservoir Rock : Rock properties
Question 16
Question 17
In a laboratory experiment, a pressure drop of 100 kP a is imposed along a core that has length of 10 cm, and a radius of 2 cm. The permeability of the core is 200 mD, its porosity is 15%, and the viscosity of water is 0.001 P a − s. 1. What will be the volumetric flowrate Q of the water, in m3/s? 2. What is the numerical value of q = Q/A, in m/s? Question 18
Consider a layered reservoir consisting of alternating layers, 1 m thick, of rock 1, rock 2 and rock 3, where k1 = 1000 mD, k2 = 100 mD, and k3 = 10 mD. 1. What is the effective permeability of this rock, if fluid is flowing parallel to the layering? 2. What is the effective permeability of this rock, if fluid is flowing perpendicular to the layering? 3. Imagine that the reservoir consists of these three rock types, in equal volumetric proportions, but occurring in a ’random’ spatial distribution. Estimate the effective permeability in this case.
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Reservoir Rock : Rock properties
Question 18
Question 19
Consider a small blob of oil surrounded by water. The surface tension between the oil and water is 0.02 N m. If the radius of the blob is 0.05 mm 1. What is the value of the capillary pressure? 2. Is the pressure higher in the oil or the water?
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Reservoir Fluid : Fluid properties
Question 19
Question 20
Table 5 is the fluid compositional data of a gas reservoir. Compute 1. the apparent molecular weight (AMW) 2. the specific gravity γ 3. the composition in weight fraction 4. the composition in volume fraction Table 5: Data from a gas reservoir Component
Composition, mole fraction
Methane Ethane Propane Isobutane n-butane
0.820 0.059 0.046 0.035 0.030 1.000
Question 21
An oil reservoir has the compositional data given in Table 6 1. What is the API gravity of the oil? Use ideal-solution principles Table 6: Data from a gas reservoir Component
Mole fraction
n-butane n-pentane n-hexane
0.29 0.40 0.31 1.00
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Reservoir Fluid : Fluid properties
Question 21
Question 22
1. The analysis of a formation water is given in Table 7. Convert the concentrations of solids for the brine to (a) milligrams per liter (b) percent solids (c) milliequivalents per liter 2. Draw a pattern of the brine Table 7: Data from a gas reservoir Component
Mole fraction
Na Ca Mg S 04 Cl C 03 HC 03
7, 365 1, 582 305 521 14, 162 705 0
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