Cement for Geothermal Wells George Trabits · Task 4 Test Second stage HPHT cement development...

1 | US DOE Geothermal Office eere.energy.gov

Public Service of Colorado Ponnequin Wind Farm

Geothermal Technologies Office 2013 Peer Review

Development of an Improved

Cement for Geothermal Wells

Principal Investigator

George Trabits

Trabits Group, LLC

Track 2 Materials

Project Officer: Eric Hass Total Project Funding: $2,154,238

April 24, 2013

This presentation does not contain any proprietary

confidential, or otherwise restricted information.


Relevance/Impact of Research

Project Objective

• Develop a novel, zeolite-containing lightweight, high temperature,

high pressure geothermal cement, which will provide operators with

an easy to use, flexible cementing system that saves time and

simplifies logistics.

Impact of New Cement Development

• Eliminate the requirement to “sterilize” pumping equipment before

use.

• Eliminate the need to foam the slurry to achieve lightweight qualities.

• Eliminate incompatibility issues in the selection of retarders and

accelerators.

• Provide predictability and minimize the effect of down-hole

temperature fluctuation.

• Facilitate the development of geothermal resources in remote

locations.


Scientific/Technical Approach

Methodology

• Build on existing zeolite-containing cement technology for low

temperature, weak formation applications.

• Systematic, scientific approach on trial cement blends to consider

the variables of:

Zeolite type

Zeolite particle size

Zeolite percentage by weight of cement

Additives for thermal stability and resistance to carbonation

• Clear and concise performance characteristics provide a systematic

method for initial screening, second stage development and

ultimately for the final stage of cement development.

• Involvement of industry for guidance on actual cementing practices.

• Solicit industry expert peer review on research methods and results.

• This logical progression of scientific study results in five Tasks that

lead to realistic project milestones and go / no-go decisions points.


TASK 1 – RESEARCH

• Literature Search

• Geothermal Cementing Practices and

Constraints

• Mechanisms of Geothermal Well

Failure

TASK 2 – DESIGN

• Compile Research Findings

• Modification of Project Tasks 3 and 4

TASK 3 – DEVELOP

• Zeolite Sample Acquisition

• Zeolite Type Confirmation

• Zeolite Particle Size Preparation

• Initial Screening of Cement

Formulations

TASK 4 – TEST

• Second Stage Cement Development

• Final Stage Cement Development

TASK 5 – DEMONSTRATE

• Laboratory Scale Demonstration

• Logistics and Ease of Use Field

Demonstration – Chena Hot Springs

Resort

• High Temperature EGS Well

Demonstration – Ormat Technologies

Scientific/Technical Approach


Accomplishments, Results and Progress

Original Planned Milestone/

Technical Accomplishment

Actual Milestone/Technical

Accomplishment

Date

Completed

Task 1 Research Completed as planned July 2011

Task 2 Design Ongoing Task Ongoing

Task 3 Develop Completed as planned Oct.2012

Task 4 Test Second stage HPHT cement

development started

In Process

Task 5 Demonstrate Resistance to carbonation started In Process

Variances

• Industry partner ThermaSource was unable to participate resulting in loss of cost share and

lab testing equipment availability.

• Schedule slippage resulting from delays in the fabrication of Chandler Engineering specialized

high pressure/high temperature cement testing equipment.



Zeolite Preparation

• Five zeolites types were selected for

cement properties screening.

• Following XRD, XRF and SEM

confirmation of zeolite type three

hundred pound bulk samples were

shipped to CCE Technologies for

preparation.

• Micronized using Jet Mill Technology.

• Prepared sizes with 80% in range:

5 micron

10 micron

44 micron

• Alternate 44 micron prepared using

Collider Mill Technology



Task 3: Screning of Zeolites

A systematic series of tests were run using the 5 primary zeolites. Each

zeolite was tested for three particle sizes: 5 μm, 10 μm, and 44 μm. For each

particle size, tests were conducted at 15%, 27.5%, and 40% cement

replacement by zeolite. Screening test were conducted at 13.5 ppg density.

Primary Screening Criteria:

• 24 hour compressive strength: 500 psi • Thickening time

• Free water: less than 5.9% (API Specs) • Consistency

Evaluate zeolites

chabazite Good properties, not retained due to high cost.

ferrierite Passed criteria for particle size <10 μm, Retained.

Mudhill clinoptilolite Passed criteria, not retained due to small size of deposit.

NM1 clinoptilolite NM1 and NM2 exhibit nearly identical properties and test

response. Meets strength criteria at 70°C and fine particle

size. Economical and adventitious deposit. Retained. NM2 clinoptilolite



12

10

8

6

4

2

0

free w

ate

r (%

)

4.4

7.0

11

.2

6.8

7.2

0.4

1.7

2.9

1.5

1.6

0.0

0.1

1.3

0.7 0

.5

1.7

6

2.2

4.4

1.7

6

2.5

6

0.2

0.2

4

0.6

8

0.5

2 0.2 0 0

0.1

6

0

0.1

6

1

1.4

4

3.6

1.2

8

0.3

2

0 0

0.4

0.4 0.3

2 0 0 0 0 0

Chabazite

Mudhill Clinoptilolite

Ferrierite

NM#1 Clinoptilolite

NM#2 Clinoptilolite

0

200

400

600

800

1000

1200

1400

1600

co

mpre

ssiv

ve s

treng

th (

psi)

31

8.0

26

0.0 33

1.0

21

0.0

23

8.0

51

2.0

22

8.0

22

7.0

23

0.0

18

7.0

13

37

.0

22

1.0

19

4.0

17

7.0

11

8.0

44 microns

15% 27.5% 40%

% cement replacement

66

0.0

33

8.0

26

9.0 32

4.0

30

7.0

15

19

.0

53

3.0

30

2.0

32

8.0

26

4.0

0.0

12

63

.0

29

7.0

44

2.0

23

4.0

15% 27.5% 40%


71

2.0

42

9.0

34

2.0

29

2.0

28

8.0

18

45

.0

59

4.0

49

1.0

28

5.0

30

5.0

0.0

0.0

50

5.0

61

4.0

49

0.0

15% 27.5% 40%


5 microns10 microns

API specs: free water < 5.9%

0

Compressive

strength and free

water data

(screening phase)

5 microns

10 microns

44 microns

0

200

400

600

800

1000

1200

1400

1600

1800

2000

com

pre

ssiv

e s

tre

ngth

(p

si)

49

1

30

2

227

18

98

16

15

950

ferrierite

45oC

594

53

3

228

16

28

131

6

909

mudhill clinoptilolite

285 32

8

230

1185

116

4

76

2

NM1 clinoptilolite

305

264

187

12

04

1160

76

3

70oC 45

oC 70

oC 45

oC 70

oC 45

oC 70

oC

NM2 clinoptilolite



Ferrierite and NM2 clinoptilolite were advanced to the HPHT testing phase along with

pozzolanic additives including diatomaceous earth

0 20 40 60 80 100 120 140 160 180

time (h)

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

3200

com

pre

ssiv

e s

tre

ngth

(p

si)

1: ferrierite_5_40%_300F_5ksi



4: ferrierite_5_27.5%_300F_5ksi

5: NM2 clinoptilolite_5_40%_300F_5ksi

6: NM2 clinoptilolite_5_27.5%_300F_5ksi

qu1

qu2

qu4

qu5

qu6

data points represent compressive strength from destructive testing

1

2

3

4

5

6

• Plot shows real time UCA compressive strength data along with the destructive compressive strength for base zeolite/cement mixes (27.5% and 40% replacements).

• UCA data under predicts the compressive strength, but provides strength development trends.

• Results suggest ferrierite offers increased strength over clinoptilolite. However, recent data suggest with increasing temperatures, clinoptilolite may not show the sharp decrease in strength observed for ferrierite.

• To date, all mixes provide adequate compressive strength up to 400

oF

• Elastic properties are similar between the ferrierite and clinoptilolite.



0 10 20 30 40 50 60 70 80

% additional silica BWOC

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

3200

3400

com

pre

ssiv

e s

tre

ngth

(p

si)

SF

SF/MDE(0/40)

(20/40)

(20/20)

(0/20)

Note: for figure, values in parenthesis indicate (% silica flour/% diatomaceous earth)

Addition of Silica for Thermal Stability

• Two silica sources were tested

including silica flour (crystalline)

and diatomaceous earth

(amorphous)

• Test conditions: 400oF for 7 days

• Silica flour: confirms literature

sources suggesting 40% BWOC is

necessary for thermal stability. This

is also confirmed by UCA data.

• Diatomaceous earth: increases

the compressive strength and

modulus of elasticity

• The long term affects of

diatomaceous earth are unknown ,

but intriguing .

Base blend:

Ferrierite_5 μm_40%_13.5 ppg



HPHT Consistency

Time (min)

Sample retarder 30 Bc 70 Bc

Ferrierite_10µm_40% base, no retarder 21 57

Baker Hughes R8 1.3% BWOC 91 104

citric acid 1% BWOB 61 91

citric acid 1%: 3% Borax BWOBpeak 36 min,

post peak drop>22 hrs

citric acid 0.6% : 1.5% Borax BWOB 36 63 *note 1 hr preconditioned at 80F

tartaric acid 0.5% BWOB 177 228 *note 1 hr preconditioned at 80F

tartaric acid 0.6% BWOB 256 338

tartaric acid 1.0% BWOB

peak (40-60

min), drop

then 910 min

>16.5 hrs.

Ferrierite_10µm_27.5% base, no retarder 57 63

tartaric acid 0.5% BWOB 619 662

Example of consistency data using 300oF results

At higher temperatures, the cement slurries require retarders to extend workability times. The

aluminous nature of zeolites shortens working times due to early reactions. A basic principle of

the study is to limit the amount of chemical additives to broaden the applicability the cement. We

have been targeting generic, non proprietary retarders focusing on hydroxycarboxylic acids and

borax. The hydroxycarboxylic are effective at 300oF. The addition of borax is necessary at

higher temperatures. The addition of borax creates setting issues.



Carbonation Studies

• Cement samples are being tested under

CO2 fluid conditions. The base zeolite mixes

as well as mixes with additional silica are

being tested. Research on carbonation

suggests that high silica additions for thermal

stability may promote enhanced carbonation.

• Cement samples are being cured in

formation fluids from the Ormat Brawley

geothermal field. These test run from 1 to 3

weeks. The fluid contains a 1.5% CO2

content and high mineral content.

• Samples are initially cured at high

temperatures up to 572oF (300

oC) and further

cured in the brine and CO2 fluids at 350oF.

Carbonation vessels


Future Directions

• Data is being extended to 572oF (300

oC) for base mixes and the addition

of various silica sources.

• Both the ferrierite and clinoptilolite have met the basic criteria up to

400oF.

• Further work needs to conducted on compatible retarders at

temperatures above 400oF. Commercial retarders may be necessary.

• Fluid loss is an issue. The effectiveness of additives will be explored.

• High demand pozzolanic additions such as diatomaceous earth and clays

may accommodate cement slurries at densities below 13.5 ppg.

• X-ray diffraction and SEM analysis will be conducted on the hydrated

cement samples for quantitative analysis of the phase assemblages.

• The phase assemblages may allow for extrapolation of the stability of the

cement to longer time periods.

• Extension of the material properties data is an ongoing process.


• The project is in keeping with Goal 2 of the MYRDD Technical Plan

to develop low-cost, high-efficiency well construction which includes

completion technology.

• The developed high temperature, high pressure geothermal cement,

will provide operators with an easy to use, flexible cementing system

that saves time and simplifies logistics.

• Systematic, scientific study is organized into five Tasks that lead to

realistic project milestones with clear and concise performance

characteristics.

• Primary screening tests completed on trial cement blends using 5

zeolite types each at 3 particle sizes (5µm,10µm and 44µm) and

each at 3 percentages (15%, 27.5% and 40%) of replacement.

• Two zeolite types advanced to Second Stage cement development

with HPHT blend testing in process.

• Effects of carbonation testing in process using actual brines from

Brawley geothermal well.

Summary


Timeline:

Budget:

• Cost share lost with ThermaSource withdrawal has been totally offset by in-kind cost share from new industry participants.

• ThermaSource cement testing equipment that became unavailable to the project has been purchased by the project and installed at the University of Alaska Fairbanks (UAF) Petroleum Development Lab.

• Established a regular monthly Peer Review of research methods and results.

• Enlisted the guidance of industry partners in actual cementing practices and constraints.

• Coordinated training of UAF students in testing methods and equipment at industry partner labs in Bakersfield and Rock Springs.

• Project Update presentations to industry associations and industry partners.

Project Management

Federal Share Cost Share Planned

Expenses to

Date

Actual

Expenses to

Date

Value of

Work Completed

to Date

Funding

needed to

Complete Work

$2,154,238 $538,557 $2,080,778 $2,094,403 $2,045,258 $762,837

Planned

Start Date

Planned

End Date

Actual

Start Date

Current

End Date

1/29/2010 12/31/2012 3/27/2010 9/30/2013

Cement for Geothermal Wells George Trabits · Task 4 Test Second stage HPHT cement development...

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