Simulating gelation of silica for in-depth reservoir plugging using IORSim as an add on tool to ECLIPSE # 1

Transcription

1 Simulating gelation of silica for in-depth reservoir plugging using IORSim as an add on tool to ECLIPSE # 1

2 The Challenge We know fluid chemistry affects flow properties on core scale (~10 cm) 1. Compaction and wettability in chalk 2. Water diversion How to translate core scale knowledge/processes to field scale? Implementation of IOR processes in the field Interpretation of field data # 2

3 NaCl Example: Effect of sulphate on oil production NaCl NaCl Na 2 SO 4 Na 2 SO 4 Na 2 SO 4 # 3 R. Ahsan, M. V. Madland, F. Bratteli, A. Hiorth A STUDY OF SULPHATE IONS - EFFECTS ON AGEING AND IMBIBITION CAPILLARY PRESSURE CURVE SCA, 34 (2012)

4 Mature Field Challenges Remaining oil ~55% Poor sweep High S or Complex flow pattern Temp. gradients Multiple Wells Mature fields Chemical EOR Geochemistry Oil Displacement Water Chemistry Need (geo)-chemistry to translate core to field Need history matched field scale reservoir models for upscaling # 4

5 The Approach IORSim Technology Eclipse Reservoir simulator Restart Files Sw, Po, Pw, qw IORSim advect components Modular interface Geochemistry Silicate Oil Rate Mg SO 4 # 5

6 A modular interface: Advection calculations separate from reactions Implicit formulation 1D : c in, N c in,1 (t + Δt) c in,2 (t + Δt) c in,n (t + Δt) Block-by-block upstream integration # 6

7 The IORSim methodology on a complex computational problem: Fast full geochemical calculations Robust, efficient solution: Transport and geochemistry solved separately and implicitly Global level (Flow) & Local (Block) level (non-linear physics chemistry) Decompose reservoir into separate flow paths Flow path is solved on a block sequentially: # 7

8 Synthetic Ekofisk Case WIII WI PI WII oil Only forward coupling Add geochemistry to ECLIPSE 8 water

9 Oil and water production rates 2X & 4X grid refinement # 9

10 Temperature No reactions Chlorine - Ekofisk field data Sulphate Calcium Magnesium # 10

11 Reactions in the reservoir Dissolution close to injectors Reservoir Surface ph potential Temperature # 11

12 To summarize: Forward coupling to ECLIPSE: Calibrate reservoir model to ions in the formation water Predict reservoir textural alterations compare with field compaction data (ongoing in the National IOR Centre of Norway) Next: Backward coupling to ECLIPSE Sodium silicate system (green chemical) Used offshore Norway to block water pathways and improve sweep # 12

13 Sodium Silicate Chemistry Gelation time gelation 5wt% Sodium Silicate Na 2 O:(SiO 2 ) n + HCl Oligomeric silicic acid Phase separation Nano sized aggregation A. Stavland, H. Jonsbråten, O. Vikane, K. Skrettingland and H. Fischer, In-depth Water Diversion Using Sodium Silicate Preparation for Single Well Field Pilot on Snorre, 16th European Symposium on Improved Oil Recovery Cambridge, UK, April 2011 B. Sebastian Wilhelm and Matthias Kind, Polymers 2015, 7, ; doi: /polym # 13

14 4 aqueous species + 1 mineral phase 1. Silica 2. HCl 3. Mobile Gel 4. Calcium 5. Immobile Gel Sodium Silicate Activator Nano size gel particles Divalent ions Rigid gel # 14

15 Permeability modification Gel formed as nanoparticles Nanoparticles aggregate Specific surface area increased, and permeability reduced Partial blocking of pore throats above critical saturation # 15

16 IORSim Backward Coupling Stop Eclipse process Update SATNUM X = EOR response, e.g.: Low sal reduce Sor Silicate reduce Perm SATNUM 1-12 # 16

17 producer Synthetic fractured reservoir View from top View from the side 4000mD 100mD injector 240x30x7 = blocks # 17

18 Production & Pressure without treatment Injector BHP Producer BHP # 18

19 5wt% silica injection for 65 days Silicate wt% Calcium wt% # 19

20 Permeability reduction Perm reduction View from top Perm Reduction View from side # 20

21 Perm reduction View from top Perm Reduction View from side # 21

22 Perm reduction View from top Perm Reduction View from side # 22

23 producer Water Saturation Profile injector # 23

24 producer Water Saturation Profile injector # 24

25 producer Water Saturation Profile injector # 25

26 producer Water Saturation Profile injector # 26

27 Production & Pressure data with Injector BHP Water Rate treatment Producer Oil Rate BHP Water Rate # 27

28 Increased recovery and reduced water cut # 28

29 Effect of grid size 240x30x7 cells 60x15x7 cells # 29

30 Conclusions Coupling between IORSim and ECLIPSE works well Block sorting implicit & modular solver Can be extended to other simulators ECLIPSE is slow compared to IORSim, can be solved by: Run ECLIPSE once Use IORSim without backward coupling to design optimal slug Then run full simulation Great potential for realistic field cases Analyse offshore two-well silicate pilot on the Snorre field Analyse Ekofisk field data for chemistry induced compaction Simulation grid could have a huge impact on the EOR effect # 30

31 Further work Further testing on full field cases Advanced silicate model with geochemistry Implementation of 2 nd order numerical schemes Separate grid refinement for chemical species Back coupling controller integrated in IORSim # 31

32 Acknowledgement: The National IOR Centre of Norway 32 #