5T. Geothermal Drilling Producing Well Integrity ... · Geothermal Drilling & Producing Well...

Geothermal Drilling & Producing Well Integrity Challenges

Colin Stuart BEng FIMechE

Ken Seymour BSc PhD MBA CEng

22 September 2016

www.stuartwright.com.sg

Presentation outline

2Private and Confidential

1. Introduction to Stuart Wright

2. Geothermal Energy Trends

3. Geothermal Drilling & Producing Well Integrity Challenges

4. Solutions to Geothermal Drilling & Producing Well Integrity Challenges

5. Summary


3

Introduction to Stuart WrightSafe and Reliable Wells

ConsultingIntelligent Risk

SolutionsTraining

Private and Confidential



2. Geothermal Energy Trends


Geothermal basics – where does the heat come from?

8 x 1012 W

32.3 x 1012 W

1.7 x 1012 W

• Clean and sustainable heat from the Earth.

• It yields warmth and power that we can use without polluting the environment.

• Geothermal heat originates from Earth's fiery consolidation of dust and gas over 4

billion years ago. At earth's core, temperatures may reach over 9000 °F.



3 BCE 1904 Present Day

The oldest known pool fed by a

hot spring, built in the Qin

dynasty in the 3rd century BCE.

Prince Piero Ginori Conti tested the first geothermal power

generator on 4 July 1904, at the same Larderello dry steam

field where geothermal acid extraction began. It

successfully lit four light bulbs. In 1911, the world's first

commercial geothermal power plant was built there.

Geothermal power plants

operating in 25 countries

globally.

Geothermal has a long history



Installed geothermal electric capacity by country

(2015)

0

500

1000

1500

2000

2500

3000

3500

4000U

nit

ed

Sta

tes

Ph

ilip

pin

es

Ind

on

esi

a

Me

xico

Ne

w Z

ea

lan

d

Ita

ly

Ice

lan

d

Ke

nya

Jap

an

Tu

rke

y

Ira

n

Co

sta

Ric

a

El S

alv

ad

or

Nic

ara

gu

a

Ru

ssia

Gu

ate

ma

la

Pa

pu

a-N

ew

Gu

ine

a

Po

rtu

ga

l

Ch

ina

Ge

rma

ny

Fra

nce

Eth

iop

ia

Au

stri

a

Au

stra

lia

Th

ail

an

d

Ele

ctri

c C

ap

aci

ty (

MW

)


950

1000

1050

1100

1150

1200

1250

1300

1350

2007 2010 2013 2015

Ele

ctri

c C

ap

aci

ty (

MW

)

Indonesia Case Study


Types of geothermal systems

HEATING & COOLING POWER

Ground-Source Heat Pumps Conventional GeothermalEnhanced Geothermal

Systems (EGS)

Simple Wells Complex Wells

- Hydraulic fracturing.

- Pump cold water from

surface through

fractures and heated

water back to surface

through a second well

to drive turbines.

- Summer: liquid moves heat from

building into ground.

- Winter: pre-warmed air & water

heats the building. Extract hot water hosted in naturally permeable

geological formations



International Energy Agency (IEA) roadmap vision of

geothermal power production by region thru 2050

“By 2050, geothermal electricity generation could reach 1,400 TWh per year, i.e. around 3.5% of

global electricity production, avoiding almost 800 mega tonnes of CO2 emissions per year.”



IEA predicted growth of geothermal power

capacities by technology

“By 2050, more than half of the projected increase comes from exploitation of ubiquitously

available hot rock resources, mainly via enhanced geothermal systems (EGS).”




3. Geothermal Drilling & Producing Well Integrity

Challenges


What is a well?

1. A well is a pressure vessel

2. It is a pressure vessel that is created in a pressure environment – drilling

3. A completed well consists of a tubular pressure vessel (tubing and casing), an adapter

(wellhead) and a series of valves (bop stack or xmas tree) – production

The challenge is maintaining wellbore integrity through both the drilling and production

phases.

BLOWOUT

PREVENTER (BOP)

DRILLING PHASE

WELLHEAD & XMAS

TREE

PRODUCTION PHASE




P ≤ 5000 psi

T < 100 °C

Onshore Onshore

Offshore (Shallow Water)

Offshore (Deepwater)

Salt Dome

PP> 10k psi

BHT>300 F

Onshore



Offshore (Ultra-Deepwater)

Salt Domes

PP>15 to 20K psi

BHT>400F

HP / HT / HPHT XHP / XHT / XHPHT / UHPHT

Rudimentary / Basic Well Design Approach

Low Importance to Material and Connection

Performances

Industry standard well

design software

(StressCheck, TDAS)

Engineered Well Design Approach

Proper Material Selection

Knowledge of suitable connection with reliable performances (ISO 13679 Cal I to IV)

Industry standard Well Design Software

(StressCheck, WellCat)

Advanced Well Design with Life Cycle

Well Integrity Approach

Industry Standard Well Design

Software with Thermal Simulation

(WellCat)


Knowledge of Full Service Connection

Performances (ISO 13679)

Well complexity

Geothermal Wells


Well integrity challenges in oil and gas wells

In a completed oil and gas well the ISO

standard recognises at least 26 possible leak

paths i.e. loss of integrity, some of which

could lead to an uncontrolled flow.

The oil and gas industry has developed

rigorous standards of best practice over the

last 100 years.

The geothermal industry has not developed

to this level of maturity, and generally follow

oil and gas well design principles.



Oil & Gas vs. Geothermal wells complexity

20161859 1904

Well

Complexity

Index

Simple Wells Complex Wells Future Wells Prediction

Oil & Gas Geothermal Oil & Gas Geothermal Oil & Gas Geothermal

Max PP (psi) 5,000 5,000 20,000 10,000 20,000 15,000

Max BHT (⁰F) 200 200 400 500 500 1,500

Location Onshore Onshore On/Offshore Onshore On/Offshore On/Offshore

Oil & Gas

Geothermal



Example loss of control events at geothermal sites

Iceland, 1999New Zealand, 1980

Australia, 2009

USA, 1998

Philippines, 2003

- Blowouts

- H2s release

- Seismicity events

- Landslides

- Pipe ruptures

- Turbine failures

Japan, 2010



Future challenges for the geothermal industry

Future growth in deeper, hotter rocks (EGS) will need increasingly complex

wells which could become even more challenging than oil and gas wells due to

extreme high temperatures.

More complex wells leads to increased blowout risk and potentially lethal risks

with high pressure water or steam, which is compounded if H2s is involved.

The Geothermal industry need to evolve more complex well skills and Risk

Management to reduce risks of uncontrolled flow.

“We cannot afford the geothermal industry to become

another fracking issue”




4. Solutions to Geothermal Drilling & Producing Well

Integrity Challenges


Solutions must suit stakeholders on all sides…

Rigorous implementation of

standards

Appropriate risk ranking

Well drilling review

Proper barrier rules

implementation i.e. RTBC

Risk of losses reduction

Better targeting of premiums

Indication that risk is manageable

Assurance that risk is manageable




1. To provide the Underwriter with a high level screening to

enable an estimated loss of control insurance premium to be

calculated.

2. The tool does not replace the Drilling Well Review in

determining the final level of risk for the well.

3. The tool is designed to identify risk elements existing

specifically for Geothermal projects.

Appropriate risk ranking



P ≤ 5000 psi

T < 100 °C

Onshore Onshore



Salt Dome

PP> 10k psi

BHT>300 F

Onshore



Offshore (Ultra-Deepwater)

Salt Domes

PP>15 to 20K psi

BHT>400F

HP / HT / HPHT XHP / XHT / XHPHT / UHPHT

Rudimentary / Basic Well Design Approach

Low Importance to Material and Connection

Performances

Industry standard well

design software

(StressCheck, TDAS)

Engineered Well Design Approach


Knowledge of suitable connection with reliable performances (ISO 13679 Cal I to IV)

Industry standard Well Design Software

(StressCheck, WellCat)

Advanced Well Design with Life Cycle

Well Integrity Approach

Industry Standard Well Design

Software with Thermal Simulation

(WellCat)


Knowledge of Full Service Connection

Performances (ISO 13679)

Well complexity

Geothermal Wells


# Geothermal Well Key Elements Risk Ranking

1Well is tapping a hot water source at a depth where temperatures exceed the boiling

point of water at ambient surface conditions

2Well is tapping a geothermal source rock where the water does not reach boiling point

at ambient surface conditions

3Well is tapping Hot Rock(s) or Enhance Geothermal System (EGS) source reservoir for

steam generation purposes

4 Geological Formations

5 Well Risk Management

6 Casing Design

7 New Technology

8 Multiple Targets/ Objectives

9 Change of Scope

10 Well Barrier Plan

11 Human Factors

Sample of high level risk ranking tool



23

People ProcessWell Control

PreparednessEquipmentWell Type

SAFE

OPERATION

MAJOR

INCIDENT

Well Control Event Risk Rating

Well drilling review




RTBC is a unique CLOUD BASED well barrier validation and monitoring solution that helps

to protect:

People

Assets

Environment

Proper barrier rules implementation i.e. RTBC


RTBC software operating environment



RTBC Daily Integrity Report sample

Wear bushing was found stuck across Blind

RAMs, but was subsequently retrieved on

20.12.2015.

Root cause investigation in progress.

Dies of spider slip fell while RIH scraper BHA.

Dies subsequently recovered via pipe RAM

bonnet after POOH BHA and closing Blind RAMs.

Root cause of dies slip fall currently unknown.

Kill line P-tested to 3000 psi for 15 mins

Valve HCR P-tested to 2500 psi for 15 mins on

04.12.2015.

Manifold P-tested to 2500 psi for 15 mins on

10.12.2015.


Summary of Geothermal integrity issues

Rapid growth of Geothermal power generation

Geothermal wells becoming more complex

Application of Intelligent Risk Solutions to assess and manage risk


Singapore Head OfficeUEN 200617028E8 Cross Street,

#28-01 PwC Building,

Singapore, 048424.

T +65 9025 7248

STUART WRIGHT PTE LTD www.stuartwright.com.sg

[email protected]

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5T. Geothermal Drilling Producing Well Integrity ... · Geothermal Drilling & Producing Well...

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