Honeywell s On-line Gas Lift Optimization Solution

Transcription

1 35 th Gas-Lift Workshop Houston, Texas, USA February 6 10, 2012 Honeywell s On-line Gas Lift Optimization Solution Ravi Nath and Sanjay Sharma Honeywell Process Solutions Houston, TX 1

2 Agenda Introduction GLO problem definition Traditional GLO solution Honeywell s GLO solution Case Study Conclusions 2

3 Introduction: Production Process mature field (no gas lift) P3 Sales Gas P4 other suppliers Choke Separator P2 Riser Water Oil Well Other Wells P1 Reservoir P1 P2 P3 P4 reservoir pressure well head pressure = P1 liquid column weight separator pressure Gas pipeline pressure Mature field: lower reservoir pressure chokes are fully open production α P 3

4 Introduction: Production Process mature field (gas lift) P3 Lift Gas P4 other suppliers Choke Separator Sales Gas P2 Riser Water Oil Well Other Wells P1 Reservoir Lift gas lightens the liquid column increases P2 increases P increases production 4

5 Introduction: Gas lift optimization problem definition P3 Lift Gas P4 other suppliers Choke Separator Sales Gas P2 Riser Water Oil Well???? Other Wells P1 Reservoir To determine the amount of gas lift to each well that will maximize oil production. 5

6 Gas lift optimization traditional solution Assumes that the separator pressure (P3) is fixed. Generates Gas Lift Performance Curves by well simulation. Determines the optimum lift gas to each well and/or generates sensitivity tables. 6

7 Gas lift optimization traditional solution work flow Step Activity Responsibility Frequency 1 Generate Gas Lift Performance Curves Production Engineer periodically 2 Generate sensitivity tables Production Engineer periodically 3 Implement gas lift optimization using sensitivity tables Board Operator hourly 7

8 Gas lift optimization traditional solution summary Traditional gas lift optimization gives benefits, but less than estimated. Can we do better? Yes! How can we do it? 1. Global optimization Consider top side constraints Compressor constraints Valve constraints Water handling constraints Consider external factors Ambient conditions Sales gas pipeline pressure 2. Real time implementation How much better? 8

9 Honeywell s on-line Gas lift optimization : HGLO 1. Global optimization Considers top side constraints Compressor constraints Valve constraints Water handling constraints Considers external factors Ambient conditions Sales gas pipeline pressure 2. Real time implementation 9

10 HGLO top side constraints - compressor P3 Lift Gas Compressor P4 other suppliers Choke Separator Sales Gas P2 Riser Water Oil Well???? Other Wells P1 Reservoir Compressor must be limiting, why? Increase in gas lift will increase gas flow to the compressor increase separator pressure tendency to reduce production 10

11 HGLO compressor constraint trade offs Gas Flow Lift gas Separator pressure Oil Flow 11

12 HGLO dynamic constraints Top side constraints can change quickly and create short term opportunities. A real time optimizer is best suited to exploit such opportunities. Examples: A drop in gas pipeline pressure A rain or drop in ambient temperature 12

13 HGLO change of state As conditions change new constraint can becoming active. Then implementing a stale optimum is not desirable; instead a reoptimization must be performed. A real time optimizer is best suited to re-optimize. Example: A lift gas valve going wide open A well comes on-line 13

14 HGLO automation A fast executing, on-line, real time optimizer is best suited for gas lift optimization. The optimizer can quickly respond to changes in the operating environment. Maximizes production. 14

15 HGLO work flow Step Activity Responsibility Frequency 1 Generate Gas Lift Performance Curves Production Engineer Periodically 2 Determine global optimum solution NOVA Optimizer Minute by minute 3 Control process and implement gas lift optimization solution Profit Controller Minute or less 15

16 HGLO - solution Honeywell NOVA optimizer State of the art SQP optimizer (with integer optimization capability) Fast execution, typically < 1 min Layered on Real Time execution platform (URT) Maximizes production subject to all constraints: top side and sub-sea Determines all lift gas flows as well as compressor operation Honeywell Profit Controller Multivariable predictive controller Inherently robust controller (patented) Manages constraints in real time Implements the optimum solution from Nova No additional instrumentation (beyond lift gas flow controllers) No changes to compressor controls Manipulates the same handles as operator 16

17 HGLO case study 8 operating wells on a platform in GOM Lift Curves from client (generated using Prosper) Traditional GLO HGLO (simulation) Benefit estimation 18

18 HGLO case study 8 operating wells on a platform in GOM. Lift Curves from client (generated using Prosper). Traditional GLO: Case 1 Case 2 Case 3 Total lift gas, MMSCFD Total production, BPD 54,954 55,362 55,951 HGLO: Total lift gas, MMSCFD Total production, BPD 55,297 55,792 56,105 Benefit: Initial production increase, BPD Initial production increase, % 0.6% 0.8% 0.9% 1 st year CF benefit *, MM$ Project NPV benefit *, MM$ * assuming : 80$/bbl, 15% IRR, 4.6 productive years remaining, linear decline 19

19 HGLO Results HGLO turned ON Production Well sensitivities, bbl/scf 20

20 HGLO dynamic constraints 21

21 Conclusions Honeywell s on-line Gas Lift Optimization (HGLO) Asset wide, real time optimization Considers all constraints including the top side Continuous constraint protection and opportunistic optimization No new instrumentation: beyond lift gas flow controllers Significant benefits: over and above traditional GLO 0.8% initial production increase 10 Million $ 1 st year CF benefit 7 Million $ NPV benefit 22

22 Questions 23

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