iptc-13405-ms definicion y fases

8/11/2019 IPTC-13405-MS Definicion y Fases

1/9

Copyright 2009, International Petroleum Technology Conference

This paper was prepared for presentation at the International Petroleum Technology Conference held in Doha, Qatar, 79 December 2009.

This paper was selected for presentation by an IPTC Programme Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, aspresented, have not been reviewed by the International Petroleum Technology Conference and are subject to correction by the author(s). The material, as presented, does not necessarilyreflect any position of the International Petroleum Technology Conference, its officers, or members. Papers presented at IPTC are subject to publication review by Sponsor Society Committeesof IPTC. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the International Petroleum Technology Conference isprohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment ofwhere and by whom the paper was presented. Write Librarian, IPTC, P.O. Box 833836, Richardson, TX 75083-3836, U.S.A., fax +1-972-952-9435.

Abst ract

Managing well integrity is essential to economically develop oil and gas resources while preserving the environment and

assuring safety to personnel.

The industry accepted definition of well integrity management is the application of technical, operational and organizational

solutions to reduce the risk of uncontrolled release of formation fluids over the entire lifecycle of the well. (NORSOK-D010)

Well Integrity assurance on the other hand is to ensure the availability and functionality of at least two well barriers during its

drilling, production and abandonment phases.

The current worldwide focus is on the development of systems and processes to manage the well operations and interventions

to assure well integrity with many claims to have a workable system that verifies and confirms the status of wells with suspectintegrity.

The bases for well integrity management systems can be categorized as;

R & D oriented systems that are built around the development of technical solutions to well construction and operational

problems. For example, the development of new inspection logs, cements, materials , equipment and techniques.

Statistically driven, those are based on the study of the historical failure frequencies and the assessment of associated risk.

Well pressure monitoring and assessment and wellhead maintenance.

Reservoir model based system that takes into consideration the reservoir development to ensure well integrity throughoutthe field development and production life.

In this paper different well integrity management systems were reviewed against worldwide industry expectations for a systemthat can manage well integrity that starts at the exploration phase and continues through its abandonment.

Introduction

Developing and implementing well integrity management systems has lately been the focus of the oil and gas industry worldwide.

During the periods of high demand for energy to fuel the expanding world economies, oil and gas fields were developed on a fast tractbasis. Wells were drilled and put online in record time as drilling days, footage, and direct costs became the exclusive performanceindicators in those periods. In addition, and in order to keep the high production potential, old wells were kept on production beyond

their projected life span.However, public awareness of the risk and hazard implications associated with the deterioration or loss of well integrity

IPTC 13405

Well Integrity Management Systems; Achievements versus Expectations Ahmed A Sultan; SPE, Qatar Petroleum


2/9

2 IPTC 13405

resulted in more stringent statutory health, safety and environmental legislation on the drilling and operation of oil and gaswells.To comply with such legislation, as health and safety guidelines, and to control the costs associated with this compliance; operatorsand service companies joined efforts to develop systems, tools and procedures to ensure the integrity of newly drilled wellsand the safety of wells that are already in operation.

Ensuring well integrity and the need to recover more hydrocarbons are two of the most critical factors decision makers in the oil andgas industry face today.

The need to manage well integrity over long time scale has not been attempted before and represented a real challenge to the industry.The complexity of processes involved in the extraction of oil and gas in addition to the high level of uncertainty associated withproduction and reservoir development scenarios are just few of the factors affecting the drilling program.The desires to ensure that wells remain viable in fields with long lives, maintenance of company reputation, and avoidance of litigationare behind the industries drive to standardize and implement well integrity management systems.

In this paper the author reviews current well integrity management systems (WIMS) against the industry objective to create a holisticapproach to implementing a management system that covers the life cycle of oil and gas wells. In addition within the definition of the

terms well integrity and Well Integrity Management new topics for future research are suggested.

Definitions

Well Integrity:

The word integrity is derived from the word integer which means a whole number and it means the state of being integral, whole or

unified and it also means soundness of construction. Between these two meanings of the word integrity one can safely define wellintegrity as the unity of well objective, design and soundness of its construction.Based on the above definition; well integrity is the qualification that testifies to the wells sound capability to perform its function tocontain and control the flow of fluids within the predetermined barriers throughout its designed life.

Consequently, the objective of a well integrity management is to ensure that wells are properly designed, executed, operated andmaintained for a definite period of time after which they are safely plugged and abandoned. Well integrity can be realized through

application of technical, operational and organisational solutions to reduce risk of uncontrolled release of formation fluids throughoutthe life cycle of a well. (NORSOK Standard D-010)Therefore a comprehensive well integrity management system should satisfy the basic requirements of providing clear guidance fromplanning phase to abandonment phase in particularly it should ensure the following:

1. In the planning and the setting of well objective phase:

The system should ensure the provision of a clear and precise well objective that is based on current reservoir development andearth model study. All possible well utilization scenarios production, injection, gas lift, to recomplete the well into a different

zone or any operation deemed necessary for field development- must be clearly stated in the well life development plan. Area ofconcern; the earth model should cover all potential risk structures above the target reservoir through accurate mapping ofgeomechanical data.

2. During the well design phase:

A well design that fulfils, in a cost effective way, the planed requirements which takes into consideration advances in technology tosatisfy safety, environmental and regulatory standards.

3. During the construction phase:

This is the shortest but most critical phase in the well life cycle as well integrity can only be verified once the well is drilled totarget and completed according to plan and design.

Hence in this phase the system must provide the tools to assess competency of well construction staff in order to assure that soundconstruction practices were followed during the drilling and completion phase.

4. And during the operations phase:

The system should set the guidelines for best operations and preventive maintenance practices and for the monitoring, recording

and management of data to maintain well integrity to end of its operational life.


3/9

IPTC 13405 3

5. Abandonment phase:

In this phase the system should assure that permanent flow control barriers are restored and to provide means for monitoring thestatus and condition of these barriers. One very important point to be considered during the design and drilling phase of any well isthat once installed and cemented in place it is not possible in most cases or practical to repair the conductor, surface or intermediate

casings. Therefore, permanent design for abandonment must be considered before the drilling of the well and implemented in thewell construction phase.

Most well integrity management systems are aimed at the operational phase of the well, leaving the well construction andabandonment phases to drilling standards and procedures.Increasing the well operational lives beyond their design life, ensuring well safety and preventing the uncontrolled escape of formation

fluids to the environment or to another formation is the objective for well integrity management systemsNo matter what standard a company follows, they all make it the responsibility of the operator to ensure safety of the public and the

environment and it is up to the individual company guidelines and procedures to control its activities and ensure compliance with thestatutory instruments in place.As a general statement the use of well integrity management systems does not eliminate well integrity problems but rather ensure thatonce wells are constructed with sound integrity they remain as such. Well integrity which is understood to be a well with sound /flawless objective, design and construction can only be accomplished in the early phases of its life. Even though very short ascompares to its operational or abandonment phases but surely the well construction phase is the most important from well integritypoint of view.

Soundness of well construction is the result of having competent staff and excellent team work. Having a clear precise well objectiveplan, that is based on reservoir development and production forecast model, eliminates the need to change the well type or categoryduring its operational life. If the well objective is not properly defined and keeps changing its well integrity assurance requirementsalso change. Managing such change is not normally performed thru WIMS but requires a more detailed in depth study to review thewell construction and verify its capability to accept the change to the new operational mode. For example, the introduction of gas leftat a late stage in a wells life, if not preplanned can lead to well integrity related problems due to high annulus pressure.Area structural knowledge is a prerequisite to quality well designs. Geomechanical mapping of the earth model is used to identifyzones of high and low pressure as well as the most likely leak path if a trapped energy source is allowed to escape. This information

which is valuable for selecting well path and casing setting points is gathered during the exploration phase from drilling and electricallogging tools and VSP and seismic data. Casing material, weight and grade selection should be designed to cover problematic zones

(high and low pressure, corrosive fluids, thermal and area of known geological structure activity).

Well Integrity Management Systems:

NORSKO D010 has been accepted as the industry standard on how to manage well integrity throughout its life cycle; hence it can beused as a guide to assess the application of the many different well integrity management systems. Accordingly most of the systems

available today cover the operational phase of a wells life. Review of a well integrity management system is not always indicative ofits potential to resolve the integrity issues that are usually specific to the region, the company or the field. While well integrity is

determined during the construction phase, the operations phase is equally important, well integrity measurement tools for this phaseinclude; leak detection, well parameters monitoring and recording, casing and cement design and evaluation, wellhead maintenanceand corrosion erosion monitoring.There is not a single well integrity system that is capable of managing well integrity in its entirety but companies can fairly assess thesystem in reference to its objective.

To compare the objective statement of the system with its deliverables.

And secondly, is the system providing the method and tools to do what is intended for it to do?

1. X WELL INTEGRITY TOOLKIT

A web based software described as a unique approach to well integrity management. The software combines the functions of:

A comprehensive database drawing together reservoir information, well design, completion condition, operating data,

inspection results, work over operations etc.

Quantitative data analysis

Immediate engineering and management feedback.

Further functions are available to provide guidance in planning and implementing work over operations.

The business benefits include:

Streamlining of data collection activities.

Improved in-company networking between departments (reservoir engineering etc.) Consistency of approach to well integrity problems.


4/9

4 IPTC 13405

Fast identification of potentially dangerous situations.

Ease of technical evaluation of problem wells and design of remedial action.

Prioritization of work over schedule.

Instant feedback to management in accessible format.

An example of a web based software that opens with field view which can be zoomed and panned to focus on particular areas.

Clicking on an individual well reveals its status according to criteria relevant to the field and company.The system will make its decision based on company inputted data and criteria for interpreting the data values. The system requiresreservoir and drilling history data to be inputted and validated, a process that works for new fields. But for old fields with limitedinformation on its drilling, completion and early production life the system administrator has to assume some values for missing data.The system collects and stores field data similar to any oil and gas data management system.

System users with administration status can adjust the rules or to post a note indicating waiver of normal rules.

Combining production and design data with well deviation data, the system calculates corrosion rate and consequently tubing life.

As the name suggests it is a tool kit, a condition based management system limited to data gathering, storing and monitoring with few

calculations to determine tubing corrosion rate. An important feature of the system is that the administrator can alter the rules and

criteria.

2. WIMS (Well Integrity Management System)

WIMS is a software solution that has been developed to meet vendor operator requirements. The system offers a practical solution to

the daily routines of well integrity management. The system is easily adjusted to meet regulatory requirements or company need. The

primary purpose of the system is to provide a tool to store and present all relevant information necessary for well integrity

management.

Well information, criticality assessment and integrity problems are aggregated and grouped / summarized to give an overview for any

number or cluster of wells...Information is logically grouped in three main categories; well information, well monitoring and well

status and each is divided into sub catagories broken down to manageable chunks of information.

In well monitoring sensor readings can be collected manually or automatically and the last read values are presented graphically along

with the alarm set limits. It simplifies and stores trend data for evaluation purposes and manages build up and bleed off pressure in the

trend graph.

In the well status category the system provides key well indicators that properly describe the well status in the sub categories: lifecycle, operational, risk, well barrier annuli and valve status.

Well Information includs the well history, operations, handovers, completion details, alarm limits that can be entered manually or

aotomaticaly.

WIMS also intended for use in the operations phase as well status monitoring tool with risk assessment cabability derived from the

risk assessment of abnormal situations. The system can be modified to meet new regulation or company rules.

Other aproatches to the management of well integrity are documented in a number of case histories but in general they apply toexisting fields with the aim of preventing uncontroled flow of formation fluids through damaged well barriers. General audit of fieldwell stock and a comperhensive risk assessment is used to in one instance (Duke& Kopeck 2007) to manage a well integrity programfor a large field in North Africa.

Case Histories and Learning Tips for Well Integrity Engineers:

The following case histories are real cases of well operations that could have been avoided through proper planning and compliance tosound oil field practices during well construction and operational phases.

Real Case 1

(Please refer to attachment #1)

A very tight super charged high pressure zone was cased and cemented without a problem and the well was completed as gas producerin 1977. The well was recompleted as a duel gas production / injection function 1991.Casing pressure was first noted in December 2005, 200-psi was recorded in annulus 1, the pressure quickly increased to reach 4200-psi. Pressure builds up after every bleed off to Zero. The effluent was 9.1 ppg brine that trickles at 18-bpd.The well was worked over and the leak was located between 8822 and 8838-ft and isolated with 4.5 liner.

Casing joint failure due to poor cement bond, thermal cycle loading (heating during production and cooling during injection) and poorjoint make up across a zone of high abnormal pressure are thought to be the most probable causes for the leak.


5/9

IPTC 13405 5

Learning points

Log, measure and record pore pressure of known high pressure zones.

Weight and grade of casing should be selected to ensure suitability of barrier.

Casing joint selection for resistance to fatigue due to thermal stress strain cycles: the thermal consideration in most wells isnot the temperature per se but the change in temperature.

Thermal cyclic loading diagram for elastic perfect plastic material and the failure of casing coupling ( Rahman and Chilingarian -

225)

Temperature change causes casing to expand or contract. (Byrom 2007)

The poor cement bond was most likely due to the high pressure salt water flow.

Below is bleed off build record gragh of real case 1


6/9

6 IPTC 13405

Real Case 2

This is a case of good well design but poor well construction practices that compromised the well integrity at the foundation stages.The result high casing pressure on annuli 2, 3 &4.

The well was partially abandoned; target reservoir was successfully isolated with cement squeeze and cement plugs. However attemptto plug annulus 3 through sidetrack and cement squeeze was not successful.

Learning point

Well abandonment of foundation structure conductor, surface and intermediate stages- should be planned and executed beforeadvancing to drill next stage.

Real Case 3

While the well was on production, oil and gas blew out of control around the well. Loss of primary and secondary well barriers wasnot noticed until the surface well structure gave in to high pressure and loss of metal strength due to corrosive salt water table near thesurface.

Learning point

Early leak detection and annuli pressure monitoring could have averted the disastrous blow out.

Real Case 4

In this case the well underwent work over to eliminate annulus pressure. But the two barrier condition was not observed when thereservoir was isolated with a wire line set plug in the R nipple below the packer. Fishing for the tubing string caused damage to theweak production casing. The well was closed in. However, the already weakened and damaged production casing could not contain

the high pressure and consequently gave in. Oil and gas flowed thru the ground and blew out at the surface near the well. A relief wellintercepted the out of control well and the well was successfully cemented off.


7/9

IPTC 13405 7

Learning point

Always consider the worst case scenario when working over old wells with high reservoir pressure. Make sure to plug and isolate thereservoir before performing any fishing or milling operations to recover the completion or repair the production casing.

Conclusion

Well Inegrity is the qualification that testifies to the wells sound capability to perform its function to contain and control the flow offluids within the predetermined barriers throughout its designed life. Managing well integrity begins with constructing wells thatcomply with integrity standards and preserving the well condition to the end of its life cycle.Present softwares, tools and applications specified as well integrity management systems fall quite short of the widely accepted

NORSOK D-010 deffinition of well integrity management system. Most of these systems are applicable to operational phase of awells life where as a comperhensive well integrity begins at the exploration phase and continues through its abandonment.

Acknowledgement

My sincere thanks to Mr. Ahmed Abdulla Khaja and Mr. Mohammed Abdulla Al-Ansi from Gas Production Department- QatarPetroleum for their help and encouragement, and to Mr. Usama Mannisseri for his valuable assistance with the editing of this paper.

References

1. Chilingarian, G.V.; Serebryakov, V.A.; Robertson, J.O., Jr., 2002 Origin and Prediction of Abnormal Formation Pressures Elsevier

2. Byrom, T. G., 2007, Casing and liners for drilling and completions, Gulf Publishing Company, Huston, TX, 304-309

3. Webb, S. and Hardy, D., 2009; A holistic approach to well integrity, Hart Energy Publishing, Houston, Texas ,

4. Duke, A. , Kopeck, J. , 2007 The Benefits of a Well Integrity Program: A Case Study, Petroleum Africa February 2007 54-57

5. Rahman, S.S., Chilingarian, G.V. 1995 Elsevier Science B.V. Amsterdam. The Netherlands.225

6. NORSIK D-010 Standard, Norway, Rev 3, August 2004

7. www.wellintegrity.net

8. www.intech.com

9. www.exprosoft.com


8/9

8 IPTC 13405

Attachment No. 1

History

The well Real case 1 was drilled in March 1977 to TD at 13540-ft to test the productivity of B formation which was found very

poor and the well was plugged back to PBTD 11650-ft and completed as gas producer. The perforated interval 10120 -10415 flowedat 71.4 mmscfd at FWHP of 4029-psi.

Three work overs were carried out in 1978, 1991 and 1999 to eliminate a tubing connection and SSD leaks, to change thecompletion string to allow duel injection/ production operations and to replace a completion string leak respectively.

Annulus # 1 High Pressure Investigation Summary

In January 2006 Annulus 1 pressure was first noted indicating a pin hole leak that bleeds off quickly but builds up quite slowly.

July 2006 TCA bled off to zero with no build up for 24-hrs. The well proved not to be a good candidate to test new ultrasound

leak detection technology.

January 2007 pressure build- up starts immediately after bleed off. Builds up to maximum pressure in 3 to 4 days.

Finally pressure build up starts immediately after Bleed off. Builds up to max Pressure of 3931-psi in less than 24-hrs. If

allowed to flow freely it trickles 1.209 SG effluents at +/- (18-bbls per day).

A review of the cement bond log revealed bad to no cement around 7 casing in the area where the leak is suspected.

A temperature survey did not pin point the leak.

The well was recommended for work over. Perforations were squeezed, then using a test packer the leak was located between 8822and 8838-ftand subsequently isolated with 4.5-liner.

1.209 SG is equivalent to 10.1 ppg brine gives hydrostatic pressure of 5100 and 4065-psi at the packer and 9 5/8 casing shoe

respectively.

Adding surface pressure of 4200-psi results in 9031 and 7996 -psi at packer and shoe depth.

The leak was located between 8838 and 8822-ft

Most probable causes:

olost joint seal due to thermal cycling cooling during gas injection and heating as the well is put on production

oJoint not properly made up during construction phase

oFailure to detect the super charged pressure zone.


9/9

IPTC 13405 9

Conclusion No I well integrity is compromised due to loss of primary barrier.

After locating the leak it was isolated with 4.5, 12.6 #/ft Liner. The well was re-perforated and completed

Conclusion No 2 Once the integrity of a well is compromised it can only be reestablished at lower service capacity (injection /

production potential)

iptc-13405-ms definicion y fases

Documents