Influence of air injection rate on combustion process

Transcription

1 ANNUAL MEETING MASTER OF PETROLEUM ENGINEERING Influence of air injection rate on combustion process Experimental campaign on combustion tube Luis Pires_May /May/214 Instituto Superior Técnico 1

2 Temperature [ºC] In-situ Combustion (ISC) CONSISTS IN: Injection of gas with the presence of oxygen in the reservoir, which in contact with the existing oil undergoes oxidation, releasing heat energy; This reaction provides the initial energy needed for another installment fuel burn, promoting a chain reaction, which is called combustion front. 2 Combustion zone OIL COMBUSTION MOTIVATION 3 Deposition zone 4 Steam plateau Injector well Producer well 28/May/214 Instituto Superior Técnico 2

3 Uncertainty and risc Motivation Quick feedbak to improve design Production Operation Manegement and Optimization Laboratory tests: Thermoanalysis Reaction kinetics Combustion tube OIL COMBUSTION MOTIVATION Workscope and Investment [3] IMPORTANCE OF COMBUSTION TUBE EXPERIMENTS Physical simulation of a small volume of reservoir subjected to similar conditions; Low costs and risks; Parameterization of reservoir and fluids properties and operating conditions; Infer what the system's behavior by changing one of its properties. 28/May/214 Instituto Superior Técnico 3

4 Gas Temperature [Deg C] Experimental campaign Oil, Water & Gas Continuous Air Injection Oil, Water Thermocouple Output Display Oil & Water Run Time [minutes] [4] 28/May/214 Instituto Superior Técnico 4

5 Porous mixture Sand Porous mixture Clay Oil Water Initial saturations 5 % oil 25% water 25% gas Porosity - 43 % Initial water percentage in the oil 7% 28/May/214 Instituto Superior Técnico 5

6 Combustion tube runs From combustion tube experiments it is possible to determine several parameters which allow the evaluation of the combustion process: Combustion and condensation velocity fronts; Hydrogen/Carbon ratio; Utilized oxigen fraction; Fuel consumption; Required air, ( ) Operating conditions of experimental runs Run Id ETCIS 1 ETCIS 2 ETCIS 3 ETCIS 4 Injection rate [L/min] 2,5 3, 3,3 3,8 Injection pressure [bar] Production pressure [bar] /May/214 Instituto Superior Técnico 6

7 Temperature [ºC] Combustion tube runs Temperature profiles along the tube Steady period Combustion front Steam plateau Combustion tube length [m] Temp. ref. Temp. Platô de vapor Temp. Média 28/May/214 Instituto Superior Técnico 7

8 Combustion tube length [m] Temperature [ºC] Combustion tube length [m] Combustion front Combustion front temperature TI 2.5 L/min TI 3. L/min TI 3.3 L/min TI 3.8 L/min Injection rate [L/min] 2,5 3, 3,3 3,8 Temperature Combustion velocity Condensation velocity Steam plateau Combustion front position TI 2.5 L/min TI 3. L/min TI 3.3 L/min TI 3.8 L/min Condensation front position TI 2.5 L/min TI 3. L/min TI 3.3 L/min TI 3.8 L/min 28/May/214 Instituto Superior Técnico 8

9 Temperature [ºC] Temperature [ºC] Steam plateau Temperature profiles at.5 m Steam plateau TI 2,5 L/min TI 3,3 L/min TI 3,8 L/min Temperature of the tube and porous Sonda_TI 2.5 L/min Sonda_TI 3.3 L/min Sonda_TI 3.8 L/min Tube_TI 2.5 L/min Tube_TI 3.3 L/min Tube_TI 3.8 L/min Injection rate [L/min] 2,5 3, 3,3 3,8 Combustion front velocity 4.2 m/day 4.9 m/day 5.5 m/day 6.3 m/day Condensation front velocity 7.8 m/day 7.6 m/day 7.5 m/day 7.5 m/day Steam plateau growth 3.6 m/day 2.7 m/day 2. m/day 1.2 m/day 28/May/214 Instituto Superior Técnico 9

10 Production [g] Volume [ml] Production of fluids 12 9 Cumulative production of fluids 12 9 Volume of produced fluids TI 2.5 L/min TI 3. L/min TI 3.3 L/min TI 3.8 L/min TI 2.5 L/min TI 3. L/min TI 3.3 L/min TI 3.8 L/min VÓleo Oil volume VÁgua Water volume GRAVITY DENSITY (API) From the density tests it was observed a decreasing in the specific gravity as the oil is being produced, resulted by the increase of the light composition and the upgrading of the heavy crude oil. Injection rate [L/min] Recovery factor [%] Min API Max 2, , , , /May/214 Instituto Superior Técnico 1

11 Combustion tube length [m] Temperature [ºC] Volume [ml] Temperature [ºC] Production of fluids Produced fluids_ir 3.8 L/min Temperature profiles_ir 3.8 L/min Fluidos Óleo Água Fluids Oil Water Velocity of the fronts_ir3.8 L/min Combustion tube length [m] Temperature profiles_ir 3.8 L/min FCombustão Combustion front FCondensação Condensation front SF1 SF2 SF3 SF4 SF5 SF6 SF7 SF8 SF9 SF1 28/May/214 Instituto Superior Técnico 11

12 Concentration [%] Temperature [ºC] Production of gases Produced gases concentration Steady period N2 CO CO2 O2 Temperature profiles 6 Steady period Combustion tube length [m] STOICHIOMETRIC EQUATIONS AND COMBUSTION PARAMETERS From combustion tube runs it is collected various data such as temperature, pressure and composition of the produced gases, enabling to establish the stoichiometry of the chemical reactions occurring during the process. From that it can be determined several parameters that characterize the combustion process. CH FHC + 2m + 1 2m F HC 4 O 2 1 m + 1 CO m + 1 CO + F HC 2 H 2O m = [CO 2] [CO] HC = H C 28/May/214 Instituto Superior Técnico 12

13 Combustion parameters Injection rate 2.5 L/min 3. L/min 3.3 L/min 3.8 L/min Parameters G.A. (1) Chrom. (2) G.A. (1) Chrom. (2) G.A. (1) Chrom. (2) G.A. (1) Chrom. (2) [O 2 ],91,9,86,5 1,4 2,23 1,9,9 [N 2 ] 83,39 84,6 83,41 84,25 83,4 81,1 83,36 84,6 [CO],58 4,11,58 3,94,54 4,17,57 4,11 [CO 2 ] 15,11 11,2 15,15 11,75 15,2 12,5 14,99 11,2 H/C ratio 1,16 2,4 1,16 1,86 1,16,83 1,15 2,4 Air-Fuel ratio [m 3 std/kg] 11,92 11,61 11,89 11,43 12,2 11,19 12,2 11,61 Utilized oxigen [Fraction],96 1,,96 1,,95,89,95 1, Excess of oxigen [Fracion],5,,4,,5,12,5, Oxigen converted in carbon oxides [Fraction],77,63,77,65,77,81,77,63 Fuel consumption [kg/m 3 std] 18,9 19,68 2,88 21,95 19,96 2,85 19,54 2,53 Required air [m 3 std/m 3 ] 225,22 228,49 248,31 25,82 23,17 223,81 234,85 238,37 Ratio (CO 2 +CO)/CO 26,95 3,72 27,15 3,98 28,76 4, 27,13 3,72 Ratio (CO 2 +CO)/N 2,19,18,19,19,19,21,19,18 (1) G.A Gases analizer; Ratio (CO 2 )/CO (2) Chrom. - Chromatography 25,95 2,72 26,15 2,98 27,76 3, 26,13 2,72 28/May/214 Instituto Superior Técnico 13

14 Conclusions Oil recovery: the oil recovery factor was higher than 85% in all runs; Quality of the produced oil: there is an upgrading of oil along the combustion process; Gases concentration: in the steady period of the gases production presented similar concentrations; Combustion parameters: Air-fuel ratio, fuel consumption, air required were similar in all runs; H/C ratio: higher than 1, indicating that the formation of fuel comes from the heavy fraction of oil. Residual oil in final mixture: practically negligible, having less than 1% in all runs; Heat transfer along the tube: it is believed that in a dry combustion tube the heat transfered along the tube to the mixture has an important influence on the formation of a steam plateau. Injection rate Combustion front velocity Steam plateau growth Velocity of fluid production Interference of heat transfer along the tube OIL COMBUSTION MOTIVATION 28/May/214 Instituto Superior Técnico 14

15 Thank you for your atention Curricular Intership 213/14 Luis Carlos Oliveira Pires Department of Petroleum Engineering Unicamp 28/May/214 Instituto Superior Técnico 15

16 Bibliografy Laboratorial tests: [1] SARATHI, P. S., In-Situ Combustion Handbook Principles and Practices, Thermoanalysis BDM Petroleum Technologies, Oklahoma, 1999 Reaction kinetics [2] [3] Combustion tube [4] Sidhartha Sur; In Situ Combustion: Laboratory to Field, Presentation at ICP, Ecopetrol, Bucaramanga, Colombia, May 21 IMPORTANCE OF COMBUSTION TUBE EXPERIMENTS Physical simulation of a small volume of reservoir subjected to similar conditions; Low costs and risks; Parameterization of reservoir and fluids properties and operating conditions; Infer what the system's behavior by changing one of its properties. 28/May/214 Instituto Superior Técnico 16