# Presentation: 809704

## Long Term Integrity of Cement Systems

- June 19, 2003

## Agenda

- Participants/Financials
- Project Focus/Management
- Project Tasks
- Summary Action Items
- API Test Data
- Seal Tite Test Results

## Participants

- Commitments
- MMS, Petrobas, Unocal, BP, ExxonMobil
- Saudi Aramco, ONGC, Conoco, AGIP
- DOE, *PDVSA, HES, Dominion
- Potentials
- Marathon, Stat Oil, Devon,

## Financials

- Commitments - $50k each
- $650k 13 Companies
- Potential additional $100 to 150k
- To date - $450
- Project Timing – 18 months

## Management of Project

- Fred Sabins – Project Manager
- Bryan Simmons – Operations Manager
- Lab support
- CSI
- Westport Rock Mechanics
- Mathematical Analysis – University of Houston
- Rock Properties Instruments - Chandler

## Project Communications

- Steering Committee – Voting Members
- Meeting notes/ voting privileges
- Quarterly Progress Report/Meeting
- June 2003
- October 2003

## Project Objective

- Determine the cement system properties that effect the ability of cements to seal fluids
- Primarily in Deep Water
- General application
- Develop a correlation of the cement properties to performance
- Determine laboratory methods to determine key properties

## Tasks

- Task 1 – Problem Analysis
- Task 2 – Property Determination
- Task 3 – Mathematical Analysis
- Task 4 – Testing Baseline
- Task 5 – Refine Procedures
- Task 6 – Composition Matrix
- Task 7 – Conduct Tests
- Task 8 – Analyze Results
- Task 9 – Decision Matrix

## Testing Program

- Deep Water/All Conditions
- Cement Slurries
- Class A
- Foamed Cement
- Bead Cement
- Class H
- Latex Cement
- Fibers, Expansion additives

## Performance Issues

- Flow of fluids
- Around the cement
- Bonding, microannulus, deformation
- Through the cement matrix
- Cracking, permeability changes
- Under stress
- Pressure, temperature
- Cycling conditions

## Testing Program

- Cement design performance Mathematical modeling
- Mechanical properties
- Performance

## Cement Design Performance

- Standard cement design testing
- Thickening time
- Compressive strength
- Rheology
- Free water

## Mathematical Modeling

- University of Houston Numerical Model
- Stress states with thermal and pressure cycling
- Tensile stresses of 1,000 to 2,000 psi possible
- Formation strength governs failure

## Mechanical Properties

- Tensile strength
- Young’s modulus
- Poisson's ratio
- Hydrostatic pressure cycling
- Fatigue/anelastic strain

## Tensile Strength

- Brazilian Test Method
- Tensile Strength Young’s Modulus
- Maximum Yield

## Testing Device

- Samples are oriented on side for tensile strength tests.
- Force is applied by constant displacement of bottom plate.

## Tensile Strength and Young’s Modulus

| Slurry  | Tensile Strength(psi) | Young’s Modulus |
| --- | --- | --- |
| Foam(12ppg) | 253 | 3.23 E 4 |
| Type I | 394/213 | 19.15/8.16 E 4 |
| Type I with Fibers | 1071 | 9.6 E 4 |
| Latex | 539 | 5.32 E 4 |
| Latex with Fibers | 902 | 8.5 E 4 |

## C Young’s Modulus

- Compressional Tests
- Confining Loads – Defined by 0psi break
- Base line 14 day cure
- Acoustic Data
- Poisson’s Ratio

## Young’s Modulus Results

## Correction

- Recently discovered correction factor accounts for instrument strain
- Next report will have corrected information

## Poisson’s Ratio Results

- Variable depending on:
- Stress Rate
- Slurry Type
- Air Entrainment

## Poisson Ratio, 50 psi 250 psi/min

| Slurry | Failure
psi | V Radial |  |  |
| --- | --- | --- | --- | --- |
| Foam | 3100 | 0.000* |  |  |
| Bead | 4100 | -0.01* |  |  |
| Class H | 6450 | 0.0012 |  |  |
| SMS | 920 | 0.005 |  |  |
| Type 1 | 6500 | 0.1 |  |  |

## Strain Amounts/Cycling

| Slurry | 1000 psi  | 2000 psi | 3000 psi | 4700 psi |
| --- | --- | --- | --- | --- |
| Foam | 0.00261 | 0.00167 | ------- |  |
| Bead | 0.00191 | 0.00158 | 0.00115 |  |
| Class H | 0.00161 | 0.00150 | 0.00102 |  |
| Type 1 | 0.00108 | 0.00080 | 0.00069 |  |

## Acoustic Measurements

- Chandler’s New Mechanical Properties Device

## Anelastic Strain Procedure

- Measure failure stress.
- Apply stress equal to 25%, 50%, or 75% of failure.
- Measure deformation.

## Anelastic Strain Results

**Bead Slurry, Confining Pressure = 0 psi, ****250 psi/min, cycle 25% of failure stress**

## Performance Tests

- Shear Bond Measurements (Cycling conditions)
- Soft Formations
- Intermediate Formations
- Hard Formations
- Annular Seal/Hassler Sleeve (Cycling Conditions)
- Soft Formations
- Intermediate Formations
- Hard Formations

## Shear Bond Molds

- Each sample is cured in a simulated hard, intermediate, and soft formation configuration.
- A steel external pipe is used to simulate a hard formation; PVC to simulate an intermediate formation.

**Simulated Hard or Intermediate Formation**

## Old Temperature Cycling Procedure

- After curing, entire sample heated and cooled in water baths from 45 to 180 and back.
- Testing after 5 cycles

## Pressure Cycling Shear Bond

- Cure specimens for 7 days at 80°F.
- Apply 5,000 psi hydraulic pressure to the inner pipe and maintain for 10 minutes.
- Release the pressure and wait 10 minutes.
- Repeat the cycle four times.
- Perform the shear bond test.

## Shear Bonds

| System | Type 1 | Foam | Beads | Latex |
| --- | --- | --- | --- | --- |
| Base P | 1194 | 127/98 | 109/78 | ---- |
| Base S | 198 | 233 | 143 | 223 |
| Temp P | 165 | 299/215 | 191/269 | ---- |
| Temp S | 72 | 7 | 56 | 149 |
| Press P | 194/106 | 276/228 | 294/170 | ----- |
| Press S | 23 | 22 C | 23 C | 11 |

## New Temperature Cycling Procedures

- Samples are then cured at 80°F for 7 days.
- Samples are then temperature cycled from 80°F to 180°F to 80°F as described below:
- Internal pipe heated to test temperature in 8 hours
- Held static for one hour
- Cooled to 80 F

## Annular Seal Testing

- Three molds are used to prepare samples.
- Soft Formation—a soft gel mold provides a semi-restricting force on the outside of the core during curing
- Intermediate Formation—a 3-in. diameter Schedule 40 PVC pipe contains the slurry
- Hard Formation—a 3-in. diameter Schedule 40 steel pipe provides a restricting force outside of the core during curing

## Annular Seal Test Configurations

## Annular Seal Test Procedure

- Mix cements and pour into molds.
- Cure for 7 days in an 80**°**F water bath.
- Apply hydraulic pressure to the inner pipe or heat the inner pipe to simulate thermal/pressure cycling.
- Test flow after each specified cycle
- Test three specimens from each test composition/formation scenario.
- Different procedures are used to test each of the mold types.

## Soft Annular Seal Test Model

## Annular Seal Test Results

| Annular Seal Test | Class A | Foamed | Bead |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Initial Flow,Hard | 0 Flow | 0 Flow | 0 Flow |  |  |  |  |
| Initial Flow,Soft | 0 Flow | 0.5 md | 0 Flow |  |  |  |  |
| Temp-Cycled,Hard | 0 Flow | 0 Flow | 0 Flow |  |  |  |  |
| Temp-Cycled,
Intermediate |  |  |  |  |  |  |  |
| Temp-Cycled,Soft | 0 Flow | 123 md/(2200 md) | 43 md(cracked during cycling) |  |  |  |  |
| Pressure-Cycled,Hard | 0 Flow | 0 Flow | 0 Flow |  |  |  |  |
| Pressure-Cycled, Soft | 27 md | 0.19 md(cracked during cycling) | 3 md |  |  |  |  |

## Pipe in Pipe Testing

- 10’ models of 2” pipe
- Pressurized to 1000 psi
- Cured for 8 days
- 100 to 500 psi
- Measured Flow rates for months

## Future Work

- Complete Annular Seal and Shear bond testing
- Complete Anelastic Strain Testing
- Begin Decision Tree