N-SOLATE Thermally Insulating Packer Fluid Systems

Transcription

1 N-SOLATE Thermally Insulating Packer Fluid Systems Jay Turner Baroid

2 Introduction Why Insolated Packer Fluids? Uncontrolled heat loss from production tubing presents a host of challenges for deepwater, heavy oil and geothermal well designs Drilling Engineers and Operators Prevention of annular pressure build up Completion and Reservoir Engineers Reduced well productivity Deposition of paraffin and asphaltenes Formation of gas hydrates

3 Heat Loss from Production Tubing Heat is lost to outer annuli Non-insulated Packer Fluid High Temperature Produced Fluids Insulated Packer Fluid Minimal Heat Is Transferred Production tubing is thermally isolated

4 Introduction Past Methods of Controlling Heat Loss from Tubing Multiple methods have been applied: Vacuum insulated tubing (VIT) Non-aqueous insulating packer fluids Aqueous insulating packer fluids Numerous disadvantages: VIT: cost, hot spots, strength, running IPFs: density, thermal stability, environmental, etc. Aqueous IPFs offer an attractive alternative

5 Introduction Advantages of Aqueous IPFs Less costly than VIT and some non-aqueous fluids Easily placed in annuli versus running VIT Potentially more reliable than VIT Can be formulated solids-free versus non-aqueous fluids Can be more environmentally friendly than non-aqueous fluids

6 Introduction Challenges with Aqueous IPFs Engineering a fluid with low inherent thermal conductance Developing a viscosifier package with adequate thermal stability over time Breaking the industry paradigm concerning other options

7 Developmental Objectives

8 Modes of Heat Transfer Conductive Convective heat source With both modes intact, heat transfers quickly through liquids heat source To minimize the transfer of heat, we need to combat both modes Low inherent conductivity (use low k liquids) Gel the fluid to help prevent convective currents

9 Thermal Limitations of Aqueous IPFs Operator testing of IPFs available in 2006 demonstrated that none were thermally stable at 275ºF for over 28 days. All test samples lost most or all of their gel performance, thus much of their insulating value. Why did this happen?

10 Eliminating Convection Traditional Polymers Synthetics and Biopolymers Synthetics and Biopolymers X-link Synthetics X-link Synthetics X-link gels Inorganics 200 o F 250 o F 375 o F Increasing Temperature

11 System Performance

12 N-SOLATE Systems N-SOLATE 275: Densities from 8.5 to 14.2 lb/gal Thermally stable to 275 F Thermally activated N-SOLATE 400: Densities from 8.5 to ~15.0 lb/gal Thermally stable to 400 F Thermally activated N-SOLATE 600: Densities from 8.5 to 10.5 lb/bbl Thermally stable to 600 F Not thermally activated

13 N-SOLATE System Performance Viscosity (cp) Viscosity (cp) N-SOLATE TM Thermal Setting of IPF One Biopolymers Time (s) N-SOLATE TM Thermal Setting of IPF Two 400 System 280 F N-SOLATE 400 N-SOLATE 275 IPF One Fluid 1 Fluid System 190 F IPF Two Thermal activation of N-SOLATE TM 400 and N-SOLATE TM 275 systems Gel strengths inhibit convective currents Gel strength and set time are each adjustable to optimumize properties Time (s)

14 N-SOLATE System Performance 2500 Viscosity vs Temp (pre set) 275 and 400 systems are initially thin Viscosity (cp) N-SOLATE 275 N-SOLATE N-SOLATE Temperature (F) 600 system is easily pumpable All systems enhibit a thixotropic rheology All systems are tunable Readings were recorded at 6 rpm (10 s -1 )

15 10000 N-SOLATE 600 System N-SOLATE F 200 F 300 F 400 F 500 F 600 F 3 rpm (5.0 s -1 ) Viscosity (cp) N-Solate rpm (102 s -1 ) Time (s) N-SOLATE Fluid Thermal conductivity, BTU/(hft o F) Density, lb/gal Fann 35 Viscometer, 600 rpm o F o F Application of nano -technology - Extreme thermal stability - Thixotropic fluid behavior 300 rpm 200 rpm 100 rpm to 10.5 lb/gal tested - Geothermal well completions 6 rpm 3 rpm Steam injection processes

16 N-SOLATE System Performance N-SOLATE TM 275 system at 300 F Day 1 Day 14 Day 28 - Note complete gelation of system - Viscosity/insulating properties increase with temperature/time

17 N-SOLATE System Performance N-SOLATE TM System Toxicity and Oil/grease Testing N-SOLATE TM Fluid Thermal Conductivity, BTU/(hr ft F) Density, lb/gal Oil and Grease*, mg/l < 0.8 < 0.8 < 0.8 < 0.8 GoM LC50**, ppm *EPA method 1664 (n-hexane extractable, Gravimetric) was used in verifying the oil and grease content **96 h LC50 bioassay testing for mysid shrimp N-SOLATE TM System Compatibility IPF compatibility was tested against predetermined contaminants: -Glycols, methanol, crude oil, control line fluids, etc. Brine compatibility was tested as well: - CaBr2, NaBr, NaCl, Formates, etc

18 Removal Strategies

19 N-SOLATE Removal Strategies System should be removable from the wellbore during interventions, etc. Fluids registering on-scale at 300 rpm on the Fann 35 viscometer are readily pumpable (300 dial reading at 300 rpm 3000 cp) N-SOLATE 275 and 400 systems are thin when placed and then will thermally activate to minimize convective currents N-SOLATE 600 is placed thick but is highly shear-thinning

20 N-SOLATE Removal Strategies Viscosity vs Temp (post set) Tunable gelation Viscosity (cp) N-SOLATE 275 N-SOLATE 400 N-SOLATE 600 Adequate viscosity to minimize convection Pumpable from the wellbore psi lift pressure Temperature (F) Readings were recorded at 6 rpm (10 s -1 )

21 Summary of Experiments Property Environmentally friendly Thermal stability Thermal conductivities (k) Density range Tunable rheology Contaminant compatibility Hydrate inhibitive Low TCT Commercially available additives Can be removed from annulus Essentially non-corrosive Details Passes oil and grease; GOM toxicity F or C BTU/hft F 8.5 ~ 15.0 lb/gal or 1.02 ~ 1.80 SG Pump viscosity, gel strength, gel set time Brines, glycols, control line fluids, ph, etc psi at 40 F < 20 F at ambient < 38 F at 10,000 psi Easily obtainable Utilization of breaker or dilution Unique base fluid Attain Y Y Y Y Y Y Y Y Y Y Y

22 QUESTIONS?