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Petroleum & Petrochemical Engineering Journal Research Article 5 min read

Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature

Olanrewaju AO*
* Corresponding author
ISSN: 2578-4846  10.23880/ppej-16000178  Received: November 14, 2018  Published: November 30, 2018
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 8 references
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Keywords
Flow-line Gathering station Corrosion thickness Output temperature Aspen Hysys software Well stream Stream composition Heat losses
Abstract

Oil and gas is transported from the wellheads to the gathering stations through pipelines called surface production flowlines. Flow-lines are located at the oil and gas well site and tied to specific wells. Flow-line may be a metallic pipe or a hose. Flow lines may be in a land or subsea well field and may be buried or at grade on the surface of land or seafloor. Most flow lines are very short in length but others may be run for kilometres in larger well fields. Usually, external environment of a surface production flow-line is at lower temperature compared to the flowing fluid temperature in the production flow-line. The interaction of the internal and external temperatures of the oil and gas surface production flowline is a major cause of temperature drop in flow-line. Undesirable and excessive temperature drops must be prevented in oil and gas production flow-line by suitable and economical sizing of flow-line insulation materials. One of the industry requirements of the oil and gas production flow-line is to ensure the flow-line meets a discharge or an output temperature. This paper focuses on choosing and sizing of an insulation material to meet an output temperature of an oil and gas surface production flow-line. Two well stream flows were developed based on stream compositions from the two oil and gas wells. It is desirable that the discharge or output temperature of the discharge fluid at the discharge end of the flow-line does not fall below 20 degree Celsius. The thermal insulation thickness for the 1 km long production flow-line was designed using Urethane Foam insulation material. The chemical processes were modelled in Aspen Hysys and a case study was developed between flow-line output temperature and the flow-line insulation thickness to correlate the two variables.

Introduction

Transportation of petroleum products through pipeline presents considerable risks including wax formation and deposition as a result of heat loss of fluids, which is harmful to the flow due to the reduced inner diameter or totally blocked pipelines in extreme cases [1]. To ensure efficient and economical hydrocarbons transport from wellhead to processing facilities, flow assurance is important in planning and designing of flow transport system [2]. Flow assurance thermal management techniques include insulation, pipe burial, electrical heating, and hot fluid circulation [2].

Apart from conveyance of oil and gas from the wellheads to the gathering stations, surface production flow-lines are also expected to limit heat losses to the external environments. In deepwater oil exploration, wells are located far from platforms, and crude oil often has to be transported over long distances in subsea pipelines [3]. The oil is cooled on its way to the destination due to heat transfer, through the pipelines walls, with the surrounding sea water [3]. Temperature- related transportation problems can take place especially if the production flow-line is not properly and sufficiently insulated against heat losses to the external environment [4]. This may lead to the precipitation of asphaltenes and/or paraffin wax and the formation of hydrates [4].

Thus, during engineering design of subsea production flow-line, it becomes mandatory to have proper insulation type and insulation thickness selection done at the early stages of project, so as to assure the proper flow of the fluids in the flow-line, at desired operating conditions [5]. Thermal insulation design is a key task in oil and gas surface production flow-line. Thermal insulation is one of the most effective energy-conservation measures in hot pipes [6]. Insulation materials are very basic and important requirement in any industry dealing with various heat transfer unit operations [7]. The basic aim of insulation is to retard the rate of heat flow in order to prevent/minimize the change of temperature of the system or the space [7].

The thickness of applied insulation material in any case of oil and gas surface production flow-line usually has a case relationship with the output temperature of the surface flow-line. In optimization of thickness of insulation over a cylindrical pipe and definition of optimum range of thickness for maximum and minimum heat transfer through the insulation at different heat inputs was carried out [8]. It is therefore necessary to build this case to serve as a guide in selecting the suitable thickness of the applied corrosion material.

Study Cases

  • Stream Composition
  • The Table 1 below shows the stream compositions from the two production wells.
  • Mol %
  • Stream Composition
  • Stream Composition
  • 1 From Well 1
  • 2 From Well 2
  • Methane
  • 0.8231
  • 0.95
  • Ethane
  • 0.0589
  • 0.03
  • Propane
  • 0.0311
  • 0 i-Butane
  • 0.0018
  • 0 n-Butane
  • 0.0021
  • 0 i-Pentane
  • 0.0009
  • 0 n-Pentane
  • 0.0011
  • 0 n-Hexane
  • 0.0003
  • 0 n-Heptane
  • 0.0005
  • 0 n-Octane
  • 0.0001
  • 0 n-Nonane
  • 0.0001
  • 0 n-Decane
  • 0.0003
  • 0
  • H2O
  • 0.0156
  • 0
  • H2S
  • 0.0003
  • 0.0042
  • N2
  • 0.0025
  • 0.0058
  • O2
  • 0.0014
  • 0
  • CO2
  • 0.0599
  • 0.01

Table 1: Stream Flow Compositions.

Other Input Design Parameters

The Table 2 shows other design parameters for simulation development in Aspen Hysys.

Copyright© Olanrewaju AO.

Olanrewaju AO. Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature. Pet Petro Chem Eng J 2018, 2(4): 000178.

ParametersValues
Length of the flow-line1000 m
Elevation change of the
flow-line		+ 5 m
Insulation materialUrethane Foam
Ambient temperature of
the flow-line		10 degree Celsius
Pipe schedule40
Pipe nominal size50 mm
Type of flow-lineBuried in soil
Buried depth1200 mm
Well 1: Stream Flow
Parameters		Mass flow rate (5000kg/h),
Pressure (2000kPa),
Temperature (50 degree
centigrade)
Well 2: Stream Flow
Parameters		Mass flow rate (4167 kg/h),
Pressure (2000kPa),
Temperature (50 degree
centigrade)

Table 2: Other Input Design Parameters.

Study Methodology

Aspen-HYSYS software is process simulation software and available at the Petroleum and Natural Gas Institute, Faculty of Earth Science and Engineering, University of Miskolc. This software package is the used around the world to design plants and to rate their performance. HYSYS was used to conduct the development and simulation of the stream compositions and stream flows from the two production wells and the 1 km production flow-line. Table 2 shows other design parameters from the two wells. A case study was set-up to investigate the correlation between the thermal insulation thickness of the Urethane Foam and the output temperature from the 1 km long flow-line. It is required that the output temperature must not drop below 20 degree Celsius.

Results

The Figure 1 below shows the process simulation of the two production wells and Table 3 shows the 96 studied cases between the thermal insulation thickness of the Urethane Foam and the output temperature that were investigated. Figure 2 shows the graphical plot of the 96 studied case results between the thermal insulation thickness of the Urethane Foam and the output temperature.

Figure 1: Process Simulation.
Click to enlarge
Figure 1: Process Simulation.

Copyright© Olanrewaju AO.

Olanrewaju AO. Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature. Pet Petro Chem Eng J 2018, 2(4): 000178.

StatePIPE-100 - InsulationFlowline Output -
Thickness mTemperature C
Case 10.02511.027846
Case 20.0311.594391
Case 30.03512.196932
Case 40.0412.80614
Case 50.04513.404548
Case 60.0513.983906
Case 70.05514.53881
Case 80.0615.067254
Case 90.06515.568872
Case 100.0716.043944
Case 110.07516.493936
Case 120.0816.920193
Case 130.08517.324165
Case 140.0917.707318
Case 150.09518.071077
Case 160.118.416798
Case 170.10518.74575
Case 180.1119.059116
Case 190.11519.357989
Case 200.1219.643374
Case 210.12519.916197
Case 220.1320.177307
Case 230.13520.427482
Case 240.1420.667436
Case 250.14520.897825
Case 260.1521.11925
Case 270.15521.332265
Case 280.1621.53738
Case 290.16521.735063
Case 300.1721.925747
Case 310.17522.109832
Case 320.1822.287686
Case 330.18522.459652
Case 340.1922.626047
Case 350.19522.787164
Case 360.222.943278
Case 370.20523.094643
Case 380.2123.241495
Case 390.21523.38335
Case 400.2223.521847
Case 410.22523.656451
Case 420.2323.787343
Case 430.23523.914692
Case 440.2424.038657
Case 450.24524.159387
Case 460.2524.277023
Case 470.25524.391696
Case 480.2624.503532

Table 3: Cases Set-up to Investigate the Correlation between the Insulation Thickness and Output Temperature.

Copyright© Olanrewaju AO.

Olanrewaju AO. Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature. Pet Petro Chem Eng J 2018, 2(4): 000178.

Case 490.26524.612646
Case 500.2724.71915
Case 510.27524.823147
Case 520.2824.924737
Case 530.28525.024013
Case 540.2925.121062
Case 550.29525.215969
Case 560.325.308813
Case 570.30525.399669
Case 580.3125.488609
Case 590.31525.575701
Case 600.3225.661009
Case 610.32525.744595
Case 620.3325.826518
Case 630.33525.906833
Case 640.3425.985594
Case 650.34526.062851
Case 660.3526.138654
Case 670.35526.213047
Case 680.3626.286076
Case 690.36526.357783
Case 700.3726.428209
Case 710.37526.497392
Case 720.3826.565369
Case 730.38526.632176
Case 740.3926.697848
Case 750.39526.762417
Case 760.426.825914
Case 770.40526.88837
Case 780.4126.949813
Case 790.41527.010273
Case 800.4227.069775
Case 810.42527.128345
Case 820.4327.186008
Case 830.43527.24279
Case 840.4427.298711
Case 850.44527.353795
Case 860.4527.408062
Case 870.45527.461533
Case 880.4627.514229
Case 890.46527.566167
Case 900.4727.617367
Case 910.47527.667848
Case 920.4827.717626
Case 930.48527.766717
Case 940.4927.815139
Case 950.49527.862907
Case 960.527.910036

Table 4: Cases Set-up to Investigate the Correlation between the Insulation Thickness and Output Temperature.

Copyright© Olanrewaju AO.

Olanrewaju AO. Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature. Pet Petro Chem Eng J 2018, 2(4): 000178.

Figure 2: Graphical Plot of the Investigated Cases between the Flow-line Output Temperature and the Thermal Insulation Thickness.
Click to enlarge
Figure 2: Graphical Plot of the Investigated Cases between the Flow-line Output Temperature and the Thermal Insulation Thickness.

References

  1. Son Tung Pham, Minh Huy Truong, Ba Tuan Pham (2017) Flow Assurance in Subsea Pipeline Design for Transportation of Petroleum Products. Open Journal of Civil Engineering 7(2): 311-323.
  2. Ogboo Chikere Aja, Ramasamy M (2016) Thermal Management of Flow Assurance Challenges in Offshore Fields- A Review. ARPN Journal of Engineering and Applied Sciences. 11(10): 1-8.
  3. Phil H (2007) Oil and gas pipelines: Yesterday and today. International Petroleum Technology Institute, ASME, New York.
  4. Boyun Guo, William C, Ghalambor Ali Ghalambor (2007) Petroleum Production Engineering: A Computer-Assisted Approach. 1st (Edn.), Elsevier Science & Technology Books, pp: 312.
  5. Okologume Wilfred, Dulu Appah (2015) Analyzing Thermal Insulation for Effective Hydrate Prevention in Conceptual Subsea Pipeline Design. International Journal of Current Engineering and Technology, pp: 2492-2499.
  6. Bassam AZ (2016) The Economic Thickness of Insulation for Steam Process Distribution Pipelines. Journal of Energy Technologies and Policy 6(2): 1-11.
  7. Gajanan Deshmukh, Preeti Birwal, Rupesh Datir, Saurabh Patel (2017) Thermal Insulation Materials: A Tool for Energy Conservation. Journal of Food Processing & Technology 8(4): 1-4.
  8. Puspendra Upadhyay, Sunil Yadav, Kiran D Devade (2017) Optimum Insulation Thickness: Radial Heat Conduction through Insulated Pipe. International Journal on Theoretical and Applied Research in Mechanical Engineering (IJTARME) 6(1-2): 163-165. Copyright© Olanrewaju AO. Olanrewaju AO. Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature. Pet Petro Chem Eng J 2018, 2(4): 000178.
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@article{olanrewaju2018,
  title   = {Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature},
  author  = {Olanrewaju AO},
  journal = {Petroleum & Petrochemical Engineering Journal},
  year    = {2018},
  volume  = {2},
  number  = {4},
  doi     = {10.23880/ppej-16000178}
}
Olanrewaju AO (2018). Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature. Petroleum & Petrochemical Engineering Journal, 2(4). https://doi.org/10.23880/ppej-16000178
TY  - JOUR
TI  - Sizing Surface Production Flow line Insulation Thickness for a Desired Output Temperature
AU  - Olanrewaju AO
JO  - Petroleum & Petrochemical Engineering Journal
PY  - 2018
VL  - 2
IS  - 4
DO  - 10.23880/ppej-16000178
ER  -