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00092513 | Petroleum Reservoir | Oil Well

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00092513
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    SPE/IADC 92513 Underbalanced Coiled Tubing Drilling Update on a Successful Campaign Randal Pruitt and Charlie Leslie, SPE, BP; Bruce Smith, SPE, WUU; Olivier Desplain and Tom Kavanagh, Schlumberger; Tony Woolham, Halliburton Energy Services; Allistar Law Baker, Hughes Inteq; Nick Christou, Weatherford GSI; and Daniel Borling, SPE, BP Copyright 2005, SPE/IADC Drilling Conference This paper was prepared for presentation at the SPE/IADC Drilling Conference held in  Amsterdam, The Netherlands, 23-25 February 2005. This paper was selected for presentation by an SPE/IADC Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers or the International Association of Drilling Contractors and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the SPE, IADC, their officers, or members. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Society of Petroleum Engineers or the International Association of Drilling Contractors is prohibited. 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 of where and by whom the paper was presented. Write Librarian, SPE, P.O. Box 833836, Richardson, TX 75083-3836, U.S.A., fax 01-972-952-9435. Introduction Located in the Emirate of Sharjah, United Arab Emirates, the Sajaa onshore gas field is a Thamama Group limestone reservoir ranging from 11,000 to 13,000 feet true vertical depth (3350 to 3960 meters). Bottomhole temperature ranges from 260 to 310 degrees Farenheight (126 to 154 Celcius) and  bottomhole pressure from 1100 to 1900 psi (75 to 129 atmospheres). This paper contains lessons learned from the  project to date by the various authors directly involved with this unique and highly successfull Underbalanced Coiled Tubing Drilling project. Background In April of 2002 the concept was conceived to utilize Under-Balanced Coiled Tubing Drilling (UBCTD) to unlock additional rate and reserves by exposing additional net pay with multilateral wellbores from the existing well stock in the Sajaa field. A full year of evaluating and planning ensued and in April of 2003 drilling for first well began. This full year of Front End Loading (FEL) was key to the success of the project and was marked by several milestones or stage gates on the way to start of operations. FEL included multiple tasks along  parallel paths to bring the project from concept through financial sanction and finally to start-up. Key tasks within the FEL were: Concept Identification: A peer assist was held with internal and external industry experts to discuss the technical options that might achieve the multilateral objectives. The two principal outcomes of the peer assist identified the basic technical concepts along with the key challenges, levers, and risks to the success of the project. Later subsurface work supported additional rate and reserves could be unlocked. Key operational challenges were: ã Personnel (people with the right skills) ã Processes (people doing the right things) ã Securing staff for critical positions ã Procedures and identification of hazards / risks ã Assurance tests for special built drilling assemblies ã Drilling models for a low reservoir energy ã 2-phase milling for the window exit point ã Equipment availability ã Procurement of long lead time materials ã  Nitrogen (liquid versus membrane) ã Ownership of the coiled tubing ã Potential loss of the motherbore; and ã  Natural gas deliverability from the reservoir  Basis of Design: A concept basis of design paper (SPE IADC 87146 by P. V. Suryanarayana; et.al.) provided the equipment sizing and  parameters. The design was necessary to prepare tenders and this effort looked at the following requirements and sensitivities: ã Pumping parameters, formation inflow performance, and hole cleaning performance necessary to size surface separation and gas compression equipment ã The coiled tubing drill string size and the need for electric line to provide surface read-out of downhole conditions ã Drilling assembly selection to efficiently operate in a 2-phase and high temperature environment Tender: The tender was structured into seven major service envelopes and one additional envelope for all required minor services. Tender invitations allowed the option for a service provider to  bid on an individual envelope or to submit a bid for any (or all) seven envelopes. Tender responses were evaluated on their technical merit as well as their safety and environmental www.petroman.ir  2 SPE/IADC 92513 management systems. Commercial evaluations were conducted separate and independent of the technical analysis. Tenders were awarded to multiple service companies as no one company could adequately provide the full range of services required.  Assurance : Assurance testing was conducted on the drilling assemblies by  pumping a 2-phase fluid (nitrogen and water) and inducing vibration to simulate downhole conditions. The tests were  performed “in an oven” at 300 F. Then an actual 2-phase milling test was completed to establish performance expectations. Several third party safety and equipment inspection audits were conducted for the coiled tubing, separation, and compression packages. Fabrication: Both local and international suppliers completed fabrication work. A majority of this “purpose built kit” was fabricated locally including the following: ã Substructure designed to provide: o Secure, multi-level work floors o Access to the BOP stack o Easy movement of the injector head o Pressure deployment of drilling assemblies ã Deployment lubricator with integral mounted winch and pressure control equipment ã Tool skid to make up the drilling assemblies on the ground (not on the rig) ã Underbalanced equipment including gas compressors and pipe work to make the necessary tie-ins to the  production flowline    Mobilization: Most of the required equipment was sourced locally. Three exceptions were: Coiled Tubing with internal electric cable; Bottomhole Drilling Assemblies; and the Surface Separation  package. The separation package was mobilized by sea from the Far East, drilling assemblies manufactured in Celle Germany, and the coiled tubing built in Houston, USA. People, Procedures & Training:   The core team of four drilling engineers and four well site leaders assembled 3-months prior to start-up. This allowed time for training, logistics coordination, and preparation of detailed procedures for both normal operations and potential emergency conditions. This core team also prepared detailed hazard identification and mitigation solutions. Start-up: A “Putting it all Together” paper (SPE / ICoTA 89644 by R.D. Pruitt, et.al.) provided detailed information about the UBCTD kit. The initial rig up was slow; as expected. Time was taken to establish safety expectations, train the crews and conduct walk-throughs of the entire site with everyone involved in the operation. Early in the project there were significant equipment failures of both the surface and downhole equipment. These failures led to several important learning’s so the team could systematically eliminate other problems as operations progressed. The most important learning was that the operator must “walk the talk” on safety when an unscheduled event occurs. It is essential for the operator to stop all operations and allow service providers the space and time to resolve technical issues safety. The lesson is to not rush through problem solving.  Drilling Program: The Sharjah UBCTD campaign has evolved as performance improved and technical capabilities established. The srcinal concept was for only two laterals of 1000-feet in length each  per well. This soon became obsolete and the campaign eventually expanded to more four laterals with a total footage in excess of 10,000 feet per well. Record footage drilled to date is 13,206 feet in four laterals using only two bottom hole assemblies. Gas production performance results speak for themselves. Themes The rest of this paper will discuss the many learning’s along the course of the project. Vision   A safe and long-term drilling campaign for unlocking rate and reserves was the vision. It was recognized at the onset that a multiple well program was required for the best chance of  proving the concept. The team “just said no” to the “one-off”  program approach. Planning for success included tendering for a 10 well campaign with triggers for early termination if needed after the first three wells. Planning for long-term success also allowed better position to negotiation campaign extensions. This approach with each service provider was time consuming, but educational as both parties had learned what their true costs were in terms of both people resources and equipment. FEL was vital to the program success with respect to planning,  procedure preparation and training. It is essential to take the time, give the space and provide funding for it. Some major concerns during the FEL period were two-phase (nitrogen gas and water) effects on motor life at 300 F. To date, this has not  been an issue. The longest bottomhole assembly run was 178-hours (over 7-days) of continuous downhole drilling with a total of 223-hours (over 9-days) of continuous circulating through the motor. Another lesson was do not stop drilling if a downhole assembly was working. www.petroman.ir  SPE/IADC 92513 3 Lessons for training include the guideline of never stop training. There will always be personnel changes during a long-term campaign no matter how hard you fight it. To minimize negative impact on the team it is essential to continue training and promote from within. This produces a visible and credible strategy as work teams see co-workers  promoted versus another outside expert come in. Results have  been astounding. It is important to establish clear program expectations up front and early with senior management and partner stakeholders. The general rule for communication about the Sharjah project expectations is “early and often”. This project has followed the classic learning curve. There are several examples of “not getting it right”, but when patience is used and space given much can be accomplished. Single point communication with senior management and partner stakeholders is important. The value of having an excellent partner relationship also pays a high dividend for all. The technical limit process was used extensively during FEL through the mobilization phase. Meetings rapidly expanded from teams deciding how to mill windows, drill formation, maintenance of underbalanced drilling conditions to moving more than 60 equipment loads in the desert safely and efficiently. The prize of reduced hours is shown on the below graph. Total Rig Move Hours 497514576915978360211111 11379 825677 7264 050100150200250300350400Sajaa 3Sajaa15Sajaa 7Sajaa16Sajaa 4Sajaa26Sjaa 32Sajaa17Sajaa42Sajaa 5Sajaa 1Sajaa14Sajaa21Sajaa15Sajaa26Sajaa19Sajaa07    T  o   t  a   l   H  o  u  r  s  The key learning from the above graph is to have a shared value in delivering the prize. If solutions benefit all companies in the project, then creative solutions will be forthcoming by all stakeholders. Real time data is extremely important and is used to make on-line decisions about operation of the underbalanced equipment, nitrogen pumping equipment, water pumping equipment, directional drilling, gas export, rate of penetration, and the list goes on. This project has all data on one single screen versus multiple screens. A Surface Computerized Acquisition Network (or SCAN) package along with technical assistance from all the service companies put all data on a single screen. Customized graphics help drilling engineers, drillers, choke operators, directional drillers and the wellsite leaders. Having data “at your finger tips” for decision-making real time has been a clear success. An example screen-shot showing a gas influx while drilling forward is shown below: Figure 1  Note the bottomhole pressure in purple rising as a fault is cut, note the green casing pressure increase. These single screen data displays are placed at strategic locations around location along with the over 20 radios (and radio protocol) to keep the operation online and “drilling ahead”. The key learning is that people get engaged at an even higher level when provided information and the understanding about how to use that data. Along with the wellsite information displays, a morning rig report is distributed to all service company supervisors,  personnel on days off, government partners, and other BP locations to keep everyone abreast of conditions and progress. This also helps sharing information, best practices and key learning’s across the team. Getting Health Safety Environment Right   Getting health, safety and environment (HSE) right is a team effort. In determination of commercial and technical viability of a newly introduced technology, recognition of the learning curve period is a must. Focus was placed on developing and adapting best practice procedures from other projects as well as lessons learned during this project. Initially, one of the main quality HSE goals was to build an interface document that would serve as a reference for any HSE matter. With over 10 companies and 20 different nationalities involved, it was obvious at the start of the project that such a document would evolve based on lessons learned during the actual project. Each operational step has been fully described and reviewed by crew leaders and management. A second goal was to initiate and develop an HSE culture driven by demonstrated commitment of senior leadership. Expectations were clearly stated prior to start-up and a system www.petroman.ir  4 SPE/IADC 92513 of recognition and rewards adopted. Visibility of management from all companies “walking the talk” helps with success. Crew incentive schemes and best safety employee contributor of the month election also helps. An onsite rig safety meeting is held twice per day where a  brief summary of actual operations are discussed and where- by all participants can express their thoughts about safety issues. Risk Assessment and Tool Box meetings are very interactive. An average of over 300 HSE “STOP” cards per month allow daily focus on HSE concerns. Additionally, wellsite operations and third-party audits are performed randomly. This maintains a high level of awareness for everyone working on the project. Teamwork is an essential part of practical safety and is largely  promoted by wellsite leaders. An HSE culture of “looking out for your team mate” is recognized and rewarded every day. Results from an engaged workforce can directly improve efficiency and reduce total non-productive time. Countless suggestions have been made using the “STOP” card process to help enhance engagement. After nearly 20-months and 700,000-hours of safe operations, the team is currently working the problem of complacency at all levels. To help fight against this false sense of HSE security, the team is re-working the entire contents of risk assessments and Tool Box Talk information. Plan-Do-Learn-Evaluate-Share   The hallmark of this project has been the extraordinary degree of collaboration among the four major service companies. Each understands that the success of the project depends upon coordinating their efforts and sharing information regarding each of their state-of-the-art (and sometimes proprietary) technology products. They understand that no single service company can supply all the technology and expertise needed for the Sharjah project. Hence, success of the project required a shared success among all the service companies. On a larger scale, underbalanced CTD worldwide would be directly affected by success or failure of this project. BP shared this global perspective and a desire that this project  be an incubator for the development of UBCTD technology. BP has opened the Sharjah drilling site to visitors from other oil companies and the project has become a showcase for the industry. It is also a showcase for future customers of the technology. In this respect, BP has provided an example of openness and cooperation. Service providers are expected to follow this example. Initially, safety and environmental protection were the top concerns. The section on the previous page addressed safety. Minimizing natural gas flaring to the environment was also a goal. Extraordinary measures were put in place to capture  produced gas and condensate while drilling forward. All hydrocarbon products are sold to the market on the same day, which is an amazing accomplishment. This required an extra measure of commitment along with extra investment. Success of “flowing-to-sales-while-drilling” added an extra measure of environmental success and efficiency as well as an additional economic benefit for the project. The performance drive to meet these progressive project goals spurred service providers to find new ways to cooperate. A key learning for service providers is to assign senior personnel to the project from the start. This helps with project planning at the start and problem solving as the project continues. All safety and environmental information was freely shared with service providers at safety meetings, operational briefings and toolbox talks. The information is also verbally translated into other languages (such as Arabic and Hindi) to ensure all  personnel on site are aware of key issues and understand  planned activities for the day. Operational results are shared and service providers respectful of propriety technologies of other companies. Each service provider understands sharing success from this project helps the future of underbalanced drilling on a larger scale. Reservoir performance enhancement in a safe way was vastly more important than the success of one individual service provider. Finally, the continued success of this project and documenting lessons learned required extra consideration. Although BP requests a high level of continuity with regard to key  personnel on site they have recognized the importance of allowing movement and transfer of personnel to help avoid complacency before it becomes an issue. Any long-term  project has this risk. To this end, service providers have been rotating some of their key people out of the project. This is accomplished in a very systematic way by moving junior  personnel up the chain of command. New personnel back fill accordingly. This is helps people grow their overall level of experience and capability. At the same time they help maintain enthusiasm and optimism. This is another example of the way the participants are taking a long-term view and focusing on the future of underbalanced drilling. Leadership   The style of leadership on any project is important; especially so when a multinational and multicultural group has to work together. Effective leadership is achieved by several means. For the Sharjah project, there is clear commitment from the top down as shown by high visibility. Senior leaders frequently visit the work location, attend crew safety meetings and set a good example by conducting advanced safety audits with the crews. Every effort is made to be diverse and inclusive of all at the wellsite. This behaviour has created a close knit working team that has a pride and passion for the  job. Front line leaders establish clear expectations with regard to safety and performance efficiency. All targets are reasonable (challenging, but achievable) and have an appropriate level of encouragement, recognition and reward. With regard to safety, an incentive program has been in operation since the start of the project. This safety incentive is made available to all www.petroman.ir
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