INNOVATIVE LOW WEIGHT CEMENT SYSTEMS CHALLENGING

Freiberger Forschungsforum 65. Berg- und Hüttenmännischer Tag vom 12. bis 13. Juni 2014

KOLLOQUIUM 1 – „Förderung und Speicherung von Erdöl, Erdgas und erneuerbaren Energien“

Lummer, Nils Recalde (Fangmann Energy Services GmbH & Co. KG)

INNOVATIVE LOW WEIGHT CEMENT SYSTEMS – CHALLENGING APPLICATIONS IN GEOTHERMAL PROJECTS

In oil well cementing, the incompatibility of drilling mud and low-weight cement slurries is a well-known

problem. The use of spacer systems to separate these two fluids and to remove residual mud filter cake

from the borehole is a common method. Here, spacer efficiency is essential for the subsequent cement

job and – even more important – for the integrity of the well. In its first part, this paper introduces a

new abrasive spacer, its development and first field application in a geothermal project.

To quantify the mud removal capacity of different spacer systems, we developed a specially customized

lab instrument. The corresponding procedure included build up and removal of mud filter cake under

dynamic conditions. Employing modified cement crushing tests, the evaluation of the spacer efficiency

was determined. Under these lab conditions, we tested the new spacer, compared it with a standard

barite-based system, and optimized its composition.

The quality of the cement job and hence the mud removal capacity of the abrasive spacer was quantified

through wireline logging. Laboratory and field results impressively proved the enhanced efficiency of

this innovative product.

In its second part, this paper presents a customized low-weight cement system specially adapted to

cement glass-reinforced epoxy (GRE) casing and presents field trials in a geothermal project. Corrosion

resistance, even under harsh borehole conditions, reduced thermal conductivity, and extremely smooth

inner-pipe surfaces are this materials main advantage when compared to steel. However, reduced col-

lapse resistance demands specially customized cement slurries. To ensure zonal isolation and hence well

integrity, appropriate adhesion of hardening cement onto the outer-surface of GRE casings is essential.

For the first field trial, the customer planned to cement 7” GRE tubulars in old corroded 9 ⅝” carbon

steel casings. Through extensive laboratory research, we formulated an optimized slurry containing blast

furnace slag cement and lightweight additives. For lab testing, we employed two new laboratory meth-

ods to evaluate the adhesion behavior of hardening cement systems on GRE casings.

The excellent quality of the first application and hence the supreme adhesion efficiency of the new ce-

ment system onto GRE surfaces was verified through wireline logging. Lab and field results impressively

manifest this blast furnace slag cement-based system as an alternative to commonly used API Class G-

based slurries. For premium results in geothermal projects, we at Fangmann Energy Services recom-

mend a combination of both innovative products.

Innovative low weight cement systems Challenging applications in geothermal projects

Berg- und Hüttenmännischer Tag Freiberg, June 10, 2016

Dr. Nils Recalde Lummer

2

Introduction

o Increase / decrease of fluid viscosity

o Retardation / acceleration of cement hydration

o Sedimentation / further detrimental chemical reactions

Incompatibility between mud and cement slurries may lead to:

Incomplete cementation / No zonal isolation

N.R. Lummer, Innovative low weight cement systems

3

Separate mud from cement slurries

Displace mud from the wellbore

Remove mud filter cake

Ensure a good cement bond

The key is spacer system which aims to:

Introduction

Introducing Power Spacer for premium mud removal


4

Development and Validation

Customized lab apparatus for spacer evaluation

Spacer systems

Drilling mud

Test cell

Pump

Sandstone samples

Fluid in

Fluid out


5


Fluids and sandstone samples

Fluid Type ρ, kg/L

Water-based mud Chalk / salt 1.27

Standard Spacer Barite 1.39

Power Spacer Barite / particles 1.39

Cement slurry API Class G 1.90

10

100

1000

10000

1 10 100 1000

Vis

cosi

ty,

cP

Shear rate, s-1

Viscosity at 22°C Power Spacer Standard Spacer

Ibbenbührener sandstone

Porosity: 19% Permeability: 200 mD


6

Evaluation of spacer efficiency

Before After

Rear

Class G

Front



7

Hydraulic press Modified cement crushing tests

Quantitative and reproducible

Shear stress = cement bond = spacer efficiency

Direct method for spacer evaluation

Evaluation of spacer efficiency



8

Power Spacer vs Standard Spacer

0

20

40

60

80

100

120

0

58

111

Sh

ear

stre

ng

th,

PS

I Mud removal efficiency

Reference Standard Spacer Power Spacer



9

Well Conditions

MD 2,400 m

TVD 2,400 m

BHP 4,500 psi

BHST 86°C

BHCT 65°C

9 ⅝” Liner cementing job for a geothermal project

Fluids

Tail cement 1.90 kg/L

Lead cement 1.60 kg/L

Power Spacer 1.32 kg/L

Mud 1.20 kg/L 0

25

50

75

100

0 10 20 30 40

Sh

ear

stre

ss,

lb/

10

0ft

²

Shear rate, s-1

Rheological profile

First Field Trial


10

Fluid WHP, bar Pump rate, L/min Volume, m³

Power Spacer 30 800 5.2

Lead cement 20 - 25 800 44.0

Tail cement 25 - 33 800 7.0

Pumping schedule

First Field Trial


11

First Field Trial

Power Spacer

#5

9 ⅝” Liner shoe USIT logs from 5 different wells

Standard Spacer

#1 #2 #3 #4


12

First Field Trial

Power Spacer

#5

Standard Spacer

#1 #2 #3 #4

9 ⅝” Liner overlap USIT logs from 5 different wells


13

Summary I

Very successful under lab and field conditions

P remium mud removal capacity

O ptimized fluid design

W ide application range

E nhanced mud filter cake erosion

R emarkable cement bond

S P A C E R


14

Introduction

o Corrosion resistance, even under harsh borehole conditions

o Reduced thermal conductivity resulting in less heat losses

o Extremely smooth inner-pipe surfaces leading to optimized flow profile

Characteristics of GRE tubular:

Introducing Fangmann’s low-weight cement system for premium adhesion on GRE surfaces and casing collapse control


Aromatic

15

Material

GRE tubular samples

Aliphatic


16

Material

Aliphatic Aromatic

Characteristics

Elastic modulus - axial N/mm² 10,300 – 20,700

Elastic modulus - radial N/mm² 22,800 – 31,100

Poisson’s ratio 0.16 – 0.38

Thermal conductivity W/m/°C 0.30 – 0.40

Material density kg/L 1.80 – 1.96

GRE tubular samples


10

100

1000

10 100 1000

Vis

cosi

ty,

cP

Shear rate, 1/s

17

Material

Cement slurries Cement Composition ρ, g/L

Slurry A Highly resistant cement, bentonite, retarder, low-weight additive A

1.32

Slurry B Highly resistant cement, bentonite, retarder, low-weight additive B

1.32

Tail slurry API Class G 1.90


18

Material

Compressive strength development

2500 psi

1300 psi


19

Shear bond test

2 Methods for Validation

Conical Mold

Ferrule

Cement

Base

GRE Sample

Plunger


20

Shear bond test


Conical Mold

Ferrule

Cement

Base

GRE Sample

Plunger


21

Lab Results

Shear bond test

Aliphatic GRE Material Aromatic GRE Material

5.3

11.5

4.5

8.9

She

ar S

tren

gth,

N/c

m²

Slurry A Slurry B


22

Tension bond test


Variable Weights

Cement Lever / Mold Assembly

GRE Sample


23

Tension bond test


Cement Lever / Mold Assembly

Variable Weights

GRE Sample


24

Tension bond test

Lab Results


0.8

13.0

0.3

3.8

Tens

ion

Str

engt

h, N

/cm

²

Slurry A Slurry B



0.8

13.0

0.3

17.0

Tens

ion

Str

engt

h, N

/cm

²

Without Wash With Wash

25

Improvement of cement adhesion

Shaft

Fluid

GRE Segment

Container

Lab Results



0.8

13.0

0.3

17.0

Tens

ion

Str

engt

h, N

/cm

²

Without Wash With Wash

26

Without wash

With wash

Improvement of cement adhesion

Lab Results


27

Adhesion on steel material

Shear Bond Test Tension Bond Test

8.8

14.0 16.7

24.4

She

ar /

Ten

sion

Str

engt

h,

N/c

m²

Slurry A Class G

Lab Results


28

Mixing of 20 L cement slurry

Cementation of 1 m 7” GRE tubular into an old 9 ⅝” casing

Use of GT Blend @ 1.32 kg/L and Glass G @ 1.90 kg/L

Calibration for logging

Preparation for Field Trials


29

7” GRE tubular cemented inside old 9 ⅝” casings (4 wells)

Field Trials

Well Conditions

MD, m 1,690 – 1,940

TVD, m 1,630 – 1,640

Max. Dev, ° 46 – 49

BHST, °C 64 – 69

BHCT, °C 46 – 53

Fluid Density, g/L Volume, m³ Pump Rate, L/min

Bentonite Pill 1.02 2 600

GT Blend 1.32 19 - 27 600

Class G 1.90 1 - 2 600


30

Field Trials

Wireline logs

Excellent Result

GT Blend Class G


31

Summary II

Very successful under lab and field conditions

Fangmann‘s GT Blend

Innovative system specially customized for cementing GRE casings

State-of-the-art low-weight cement for casing collapse control

Adhesion verified by two separate lab test methods

Premium cement bonding on GRE and steel tubular

Enhanced adhesion through the use of washes


Fangmann Energy Services GmbH & Co. KG Stimulation-Cementing-Downhole Tools Brietzer Weg 10 29410 Salzwedel/Germany

Phone: +49 (0) 3901 8363- 0 Mailto: [email protected] Web: www.fangmanngroup.com

Geschäftsführer: Frank Fangmann, Steffan Gerdes · Amtsgericht Stendal HRA-Nr. 117 Pers. haftende Gesellschafterin: Fangmann Salzwedel Beteiligungs GmbH · Amtsgericht Stendal HRB-Nr. 921

mailto:[email protected]

mailto:[email protected]

http://www.fangmanngroup.com/

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INNOVATIVE LOW WEIGHT CEMENT SYSTEMS CHALLENGING