1. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Fall 2001 ASME/API Gas Lift Workshop Aberdeen NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUMPTION OF GAS CHAMBER PUMPS

2. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Outline Introduction Numerical Model Field Test Facility Field Test Results Conclusions

3. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Introduction open Valve 2. Valve 1.closed open

4. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Introduction open Valve 2. Valve 1.closed open Valve 2. Valve 1.closed open

5. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Introduction

6. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Introduction

7. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Introduction

8. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Advantages Can Handle: gassy & viscous fluids High Temperatures (stimulation by cyclic steam injection) Can be run and pulled with wire line equipment No fallback losses Completions can be very simple Introduction

9. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Disadvantages Higher cost in surface controller equipment than in Gas Lift For complex designs parts are subject to wear and replacement A High-Pressure gas source is required Introduction

10. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP General Calculation Algorithm 1) Input data: reservoir, completion,fluid properties, separation & injection pressure 2) Calc. minimum and maximum liquid level MINIMUM LEVEL MAXIMUM LEVEL 80% OF STATIC RESERVOIR PRESSURE 3) Calc. column increments 4) For each column calculates the liquid prod. and gas consumption separately 2143….N Numerical Model

11. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Calculation procedure for each column (1,2,3,….n) Column accumulation Gas Injection Fluids displacement by gas expansion without injection Gas Venting Fluids into the well (Pgas<Pres<Pcas) No Reservoir inflow (Pres<Pgas<Pcas) No Reservoir inflow & (Pres<Pcas<Pgas) Fluid displacement Gas depressurization No Reservoir inflow (Pres<Pcas<Pgas) Model Stages Numerical Model

12. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Numerical Model Calculation procedure for each column (1,2,3,….n) Liquid Column Accumulation no yes

13. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Numerical Model Calculation procedure for each column (1,2,3,….n) All other Stages System divided in the following control volumes Gas injection tubing Liquid chamber+subsurface valve annulus space flow line

14. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Numerical Model Calculation procedure for each column (1,2,3,….n) All other Stages Initial conditions: L, Pwf, Pinj, time, gas injected=0, liquid velocity For each C.V. :Continuity, Momentum, Eq. of state, Gas flow through chokes, liquid flow through chokes Conditions at t2: L, Pwf, Pinj, time, gas injected, liquid velocity... Stage check Finish stage

15. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP open Valve 2. Valve 1.closed open Test Facility 2500 ft Pressure and temp. sensors 3 1/2” tubing R-28 23 API

16. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Test Program Average liquid column length = 520 ft Gas injection and venting stages

17. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Test Results

18. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Test Results

19. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Test Results

20. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Test Results

21. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Test Results Very inefficient completion used for the tests Very small liquid columns simulating a low producer well Tests with c-t gave less than 50% of these GLRs

22. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP Test Results

23. NUMERICAL MODEL FOR THE PREDICTION OF FLUID PRODUCTION AND GAS CONSUPTION OF GAS CHAMBER PUMPS PDVSA INTEVEP A numerical model was developed for gas chamber pumps A field scale test program was carried out on gas pumps. Even though the completion used for the tests was highly inefficient, the injection GLR measured for each test were within the economical limit. The model predicts the test results within a 10% global accuracy for the operating conditions found during the tests. Conclusions