Cementing Temperature/ The purpose of this presentation is to give an overview of the temperature simulator of CemCADE (and MudCADE).

Cementing

1. Cementing Temperature 1

2. Effects of Improper Temperature Selection Excessive WOC Time Risk of Premature Set Misapplication of Additives Potential for Gas-Migration 2

3. API Schedule Easy to use Extensively used Limited failure Have limitations 3

4. API Temperature 4

5. API Limitations Important Parameters not Considered Circulating Time and Rate Inlet Temperature Formation Properties Well Deviation Fluid Characteristics Well Geometry Deep Water Derived from Drill Pipe Measurements Well Depth (1,000 - 20,000) Temperature Gradient (0.9 ° - 1.9 ° / 100 ft.) 5

6. Temperature Simulators versus API Based on fluid flow and heat transfer law Objectives - Predict circulating temperature while cementing - Account for physical parameters neglected by API Minimize risk associated with temperature 6

7. PBHCT (API RP 10B) User inputs surface temp, TVD, BHST, type of job Temp gradient calculations From 0 to 10,000 ft uses the tables & interpolates For >10,000 ft uses API calculations 7

8. Temperature Simulator Features transient and steady-state solution calculate temperature profile in annulus and casing handle multiple fluids flow cases can be stacked to include thermal effect of prior operation handle offshore conditions default thermal properties for rock and fluid depending on composition horizontal or deviated wellbore shut-in 8

9. Temperature Software Schlumberger - CemCADE 4.1 - WTP for DataFRAC and WaterCADE - CemTEMP from SCR Others - WELLTEMP from Enertech Engineering - Gtemp from Maurer Engineering Inc - WEST from O.T.S. - HEATUP from Baker Jardine 9

10. CemCADE Temperature Simulator Overcomes Limitations of API Schedules Temperature Prediction Linked to Cementing Quantify Variable Influences Adjust Design to Well Conditions Minimize WOC Eliminate Premature Set of Cement Better Evaluation of Compressive Strength at TOC Proper Additive Selection 10

11. Basic Definitions The fields are: API BHCT Bottom hole circulating temperature based on the API standard. Simulated BHCT Temperature at the casing shoe calculated by the temperature simulator at the end of circulation. Simulated Max HCT Maximum hole circulating temperature found throughout the circulation. Max HCT Depth Depth at which Simulated Max HCT is found. Max HCT Time Time during circulation at which Simulated Max HCT is found. 11

12. Temperature Model 12 T casing T annulus Conduction Heat Transfer Conduction-Convection Heat Transfer Geothermal Profile

13. Mud Circulation Prior Cementing 13

14. Thermal Effects of Mud Circulation 14

15. Thermal Effects of Formation 15

16. Temperature Profile Temperature profile in the wellbore during circulation. 16 T z BHST BHCT Geothermal Temperature Annulus Temperature Casing Temperature

17. Rig, Well Geometry & Fluids Choice 17

18. Circulating Temperature Typical bottom hole circulating temperature versus time at constant flowrate. 18 t T BHST BHCT Steady State Transition Phase

19. Shut-In Thermal Gradient 19

20. Fluids Temp at Liner Lap 20

21. Temp vs Time with Mud Circ 21

22. Temp vs Time without Mud Circ 22

23. Equation for Heat Transfer r C p ( dT/dt + V.dT/dz ) = - dq/dr r = density C p = thermal capacity T = temperature V = fluid q = heat flux z = well depth r = radial coordinate 23 Annulus r Z Formation Casing/ Drill Pipe Rc Ra Rinf T c T a T f