Field Evaluation of an Offshore Pumping System

Transcription

1 Field Evaluation of an Offshore Pumping System Jeffrey A. Bennett 1, Augusto Garcia-Hernandez 1, Marco Antonio Muñoz Prior 2 Moisés León Dorantes 2, 1 - Southwest Research Institute 2 - PEMEX Exploración y Producción

2 Slide 2: Presenter/Author Bios Jeffrey A. Bennett (Presenter) Research Engineer, Southwest Research Institute Experienced in thermal fluid network modeling MSc Turbomachinery Aeromechanics, KTH/Université de Liège BS Mechanical Engineering, Virginia Tech Augusto Garcia-Hernandez Group Leader, Pipeline Simulation, Southwest Research Institute 12 years experience modeling pipelines and associated machinery MS Petroleum Engineering, University of Tulsa BS Mechanical Engineering, Universidad Central de Venezuela 2/22-25/2016 Field Evaluation of an Offshore Pumping System 2

3 Slide 3: Presenter/Author Bios Marco Antonio Muñoz Prior Mechanical Engineer Electrician, Design and Optimization of Crude Oil Infrastructure, PEMEX Exploración y Producción Mechanical Engineering, Instituto Politecnico Nacional Moisés León Dorantes Former superintendent in the Coordination of Transport and Oil Distribution, PEMEX Exploración y Producción Mechanical Engineering, Instituto Politecnico Nacional 2/22-25/2016 Field Evaluation of an Offshore Pumping System 3

4 Short Abstract An evaluation was performed on one of the largest offshore facilities belonging to PEMEX Exploration and Production due to forecasts predicting that future crude oil production will contain heavier oils. The primary function of the evaluation was to assist PEMEX in determining if the facility s pumps needed to be upgraded. In addition, several of the centrifugal pumps of the platform had been recently replaced with screw pumps. Therefore, the evaluation was performed in three parts: first, the remaining centrifugal pumps were evaluated in the field at available testing conditions; second, a hydraulic analysis of the network was conducted to predict the system performance with heavier oils; and third, an interactive pump simulator was developed to train operators on the new screw pump equipment. This presentation/paper will focus on the first step, the field evaluation of the centrifugal pumps, and the remaining steps will be discussed briefly. 2/22-25/2016 Field Evaluation of an Offshore Pumping System 4

5 Presentation Overview Field Evaluation System Background Performance Testing Approach Pipeline Modeling Results Field Testing Results Hydraulic Modeling Simulator Development 2/22-25/2016 Field Evaluation of an Offshore Pumping System 5

6 Presentation Overview Field Evaluation System Background Performance Testing Approach Pipeline Modeling Results Field Testing Results Hydraulic Modeling Simulator Development 2/22-25/2016 Field Evaluation of an Offshore Pumping System 6

7 Background FPSO Yùum K'ak'náab AIKMZ FSO Ta Kuntah 36" 24" 30" Rebombeo L- 4 TERMINAL MARITIMA DOS BOCAS Cayo Arcas 36" Akal-L L-1 36" L-2 24" L-2 L-2 L-1 L-3 Akal-J 36" 36" 36"36" 36" 36" Akal-N 20" 20" ABK-A RMSO Akal-B L-136" POL-A 36" Akal-C L-3 24" 36" Nohoch-A PEMEX Exploration and Production s off-shore pumping system transports approximately 50% of Mexican crude oil production Complex interconnected platform network where different crude oils are mixed Historically has operated with 19 API oil, however, forecasts predict mixtures of approximately 16 API oil Screw pumps recently installed to help transport heavier oil Aging centrifugal pumps require a performance evaluation 2/22-25/2016 Field Evaluation of an Offshore Pumping System 7

8 Rebombeo Platform The booster platform Rebombeo is located in the Gulf of Mexico approximately 25 miles off-shore Two 36-inch sub-sea pipelines travel 52 miles Platform has 10 pumps connected in parallel 6 centrifugal 4 screw (new) TB-01 TB-02 TB-03 TB-04 TB-05 TB-06 CENTRIFUGAL PUMPS LINE 1 INLET FILTERS LINE 1 OUTLET REBOMBEO PLATFORM LINE 2 INLET TB-A TB-B TB-C TB-D SCREW PUMPS FILTERS LINE 2 OUTLET 2/22-25/2016 Field Evaluation of an Offshore Pumping System 8

9 Performance Testing Goal: Traverse entire pump curve at a given speed (follow ASME PTC-8.2 Standard) This test requires the system pressure difference to decrease as the flow rate increases Platform s 6 centrifugal pumps come in 2 varieties high capacity and low capacity Can we take advantage of the different pump types? Head [Ft] 3,500 3,000 2,500 2,000 1,500 1, Pump Curves Low Capacity Pump High Capacity Pump 0 2,000 4,000 6,000 8,000 10,000 12,000 Flow [GPM] 2/22-25/2016 Field Evaluation of an Offshore Pumping System 9

10 Pipeline System Curves Pressure [PSIA] Pipeline System Curves Pipeline to Platform Pipeline from Platform Flow [GPM] Dissimilar to the pump curve, the pipeline system curve requires an increasing pressure difference for high flow rates For standard operation this is great -> stable operating point For testing a means to vary flow conditions is necessary to follow the testing standard 2/22-25/2016 Field Evaluation of an Offshore Pumping System 10

11 Sample Test Point Head [Ft] 2,500 2,000 1,500 1, Sample Test Point Test 5,200 RPM Flow - Test Pump Low Capacity 5,210 RPM Flow - Low Cap. Pump High Capacity 3,100 RPM Flow - High Cap. Pump Head Level 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000 10,000 Flow [GPM] Pumps are in parallel, thus equal head across each Test pump kept at constant speed Speed of other pumps varied to change flow through test pump Pipeline simulations used to prove approach and determine necessary test conditions 2/22-25/2016 Field Evaluation of an Offshore Pumping System 11

12 Pipeline Network and Machinery Model 1-D pipeline fluid model of the existing facility including L1, L2, and L3 lines Used previous pump field measurements to represent pump curves Various emulsion of water-in-oil up to 30% water-cut Flow, pressure, and temperature field data was previously used to validate the hydraulic model within 1.12% AKAL-J REBOMBEO L= 5.2 km AKAL-C 24 INT-26 INT L-3 L-2 L-1 L= 8.6 km INT-27 L-3 L= 5.3 km Crude Oil Pipeline System from the Production Platforms to TMDB NH-A 2/22-25/2016 Field Evaluation of an Offshore Pumping System 12 TMDB

13 Modeling Results Head [ft] 2,000 1,800 1,600 1,400 1,200 1, Predicted Pump Performance Test RPM - Corrected with Affinity Laws Test RPM - Corrected for Viscosity BEP Test Point 1: 1,846 GPM Test Point 2: 2,615 GPM Test Point 3: 3,650 GPM Test Point 4: 4,600 GPM ,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 Flow [GPM] Modeling demonstrated that test approach of varying speed of adjacent pumps is able to vary flow through the test pump However, unable to traverse entire pump curve with this approach Traverse of entire pump curve requires a change in platform operation conditions Limitation primarily due to platform pressure limits 2/22-25/2016 Field Evaluation of an Offshore Pumping System 13

14 Test Set-up: Flow Measurements Ultrasonic Flow Meter 2/22-25/2016 Field Evaluation of an Offshore Pumping System 14

15 Test Set-up: Pressure Measurements Suction Pressure Discharge Pressure Pump Speed Differential Pressure 2/22-25/2016 Field Evaluation of an Offshore Pumping System 15

16 Measured Pump Performance Only one platform flow condition available for testing limited to current production Performance test was able to traverse a portion of pump curve Results used to estimate the pump degradation Testing was performed on 3 of the 6 centrifugal pumps Head [ft] 2,000 1,800 1,600 1,400 1,200 1, Measured Pump Performance Test RPM - Corrected with Affinity Laws Test RPM - Corrected for Viscosity Test RPM - Corrected for Degradation Test RPM - Corrected for Degradation and Viscosity Measurements BEP ,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 Flow [GPM] 2/22-25/2016 Field Evaluation of an Offshore Pumping System 16

17 Presentation Overview Field Evaluation System Background Performance Testing Approach Pipeline Modeling Results Field Testing Results Hydraulic Modeling Simulator Development 2/22-25/2016 Field Evaluation of an Offshore Pumping System 17

18 Hydraulic Modeling Evaluation Pressure (Kg/cm^2) Valve Starts begins closing to Close Valve Closed SDV-3101 closed Time (min) 22,000 19,250 16,500 13,750 11,000 8,250 5,500 2,750 0 Flow Rate (GPM) After performance testing complete, additional simulations performed to predict scenarios that are undesirable for experimentation at an operating platform either due to expense or safety Water hammer scenarios used to predict worst-case pressure spikes Also simulated changes to system valve configurations 2/22-25/2016 Field Evaluation of an Offshore Pumping System 18

19 Presentation Overview Field Evaluation System Background Performance Testing Approach Pipeline Modeling Results Field Testing Results Hydraulic Modeling Simulator Development 2/22-25/2016 Field Evaluation of an Offshore Pumping System 19

20 Purpose of Developing a Training Simulator Safely train operators to use newly installed screw pumps Helps platform operators comply with API 1120, ASME B31Q, RP 1161 and RP T-2 2/22-25/2016 Field Evaluation of an Offshore Pumping System 20

21 Training on the Simulator Simulator has screens that mimic control screens and a computational engine that predicts system response to trainee actions Additional screens added to provide operators with insight into the system hydraulics Ability to simulate complex procedures such as startups and shutdowns 2/22-25/2016 Field Evaluation of an Offshore Pumping System 21

22 Conclusions Field evaluation of offshore pumps was performed Pipeline simulations were used to provide insight into test conditions necessary to perform a full sweep of pump curve Limited flow conditions in the field resulted in a limited range of the pump curve being tested Pump degradation was estimated from the field testing and adopted in the model Hydraulic system evaluation used to estimate worst-case water hammer scenarios Training simulator was developed to train operators to use newly installed screw pumps Centrifugal Pump with Shaft Guard On 2/22-25/2016 Field Evaluation of an Offshore Pumping System 22

23 Thank you for your attention! I will be happy to address any questions. Jeffrey A. Bennett Research Engineer Jeffrey.Bennett@swri.org Augusto Garcia-Hernandez Group Leader Augusto.Garcia-Hernandez@swri.org 2/22-25/2016 Field Evaluation of an Offshore Pumping System 23