SPE 38497 | Saxiety of Petoleun Engineers Overcoming the Challenges Associated With the Life-Cycle Management of Multilateral Wells: Assessing Moves Towards the “Intelligent Completion” Clark E. Robison, SPE, Halliburton Energy Services ony 1927, Sait ot Patou Eger nn oednen’ Sa 338 Setnr 097 . In pipe ae sto tr rasonabo 9 an SHE Pea Connie chow row "eveafon cranes nan usvad sbeed bye sar. Contte fap ‘ete arctan ona ra Soe ot arian Ene he Abstract The term, “Intelligent Well,” conjures up visions of a 21" century oilfield where wells are drilled into highly productive formations, and the recoverable reserves approach 100%. In this state-of the-art concept, the drilling ‘and production operations are managed from an office in a tropical paradise, the completion equipment is reconfigured so that it automatically meets the changing production needs, and all maintenance operations are performed withoat the need for an intervention. Is this grand and glorious prophesy of things to be science fiction? Perhaps — but this is how the industry wants to envision its future — and it is already taking the initial steps to turn these Jules Vernian dreams into reality. ‘This paper will discuss the challenges that the industry will face as it moves more deeply into the era of the multilateral well and on into the era of the “Intelligent Well.” The predominant areas of question include some basic philosophical concepts that are raised in the well design, the concerns of application of the technology, the risk factors that must be carefully weighed against the economic benefit, and the integration of personnel and equipment interfaces, 269 Introduction Multilateral concepts, which allow several laterals to be connected to a parent wellbore so that all laterals can be accessed and production from cach can be isolated or commingled, are now considered a viable and economic solution to many drilling programs.' The benefits from these completions include greater productive capacity, lower Grilling costs, topsides capital expense reduction, and because the directional drilling may provide more efficient Grainage, upgraded recoverable reserves. Any one of these advantages might provide the justification for the expense and risk of a multilateral well; and together, they provide a significantly strong economic case for adopting this driling and completion philosophy as part of a standard reservoir ‘management program. When combined with the superior control of the production process that the intelligent. well concept can provide, additional benefits are achieved “Intelligent well” in the generic sense isa term that can be applied to a well that has a pressure and temperature transcucer in place to monitor reservoir conditions along with a sophisticated multilateral well configuration that provides isolation of the laterals and has flow controls and sensors. to control the production processes in real-time Regardless of the actual completion hardware, avery important part of an intelligent well system is its capability 10 apply the knowledge gained from the ongoing analysis of the production data. Although initial completion costs may be greater, the value will be realized when the completion configuration controls production to provide a more efficient or effective production plateau Background Drilling horizontal wells became the vogue during the decade of the 80's. Directional drilling techniques improved at a geometric rate, and many case histories describe the economic benefits of these practices.’ The majority of these wells were extensions of existing wellbores, and the existing2 CLARK £. ROBISON producing intervals were blocked by the whipstock that allowed the offset to be drilled. The productive capacity of the well was based solely on the effectiveness of the new horizontal wellbore that intersected the primary wellbore Multilateral wells were first introduced to address the need to protect the existing producing interval as well as intersect additional producing sands from the same well To enable a well to produce from multiple laterals, techniques were developed that allowed the lower intervals to be reopened after drilling the offset, thereby increasing the productive capacity in one well by a significant margin. The procedures for drilling and completing these wells and the associated equipment are still under development by a number of major oilfield supply companies. Once proven with land wells, the move to apply the technology subsea followed quickly. ‘The additional economic advantage to completing subsea wells as multlaterals is that from a single wellbore the productive capacity of 2-3 wells is possible. This reduces the need for topsides facilities because fewer wells are required. In many cases, the reservoir models that were created to predict the behavior of these producing giants showed that commingling the production from the various intervals ‘would further enhance the economic value of the asset. This brought about the need for advanced controls in the well, The intelligent well was initially perceived as an enhancement to production operations; improving the control of the producing intervals. As has often occurred in the history of technological development for the oilfield, the idea of combining two concepts to obtain the advantages of both is primary driver in the development of technology. And as mulilateral techniques became more accepted, 2 greater realization was acknowledged. The economics of, commingling the production from the laterals is very attractive, and now, many operators consider the combination of the two technologies as an essential part of the well planning Ithas already been proven that employment of advanced sensors and controls will improve the management of the production processes, and this prognosis provides the starting point for a reservoir management system, AS the downhole systems (described in more detail below) evolve, the software development must also keep pace to insure that the maximum benefit from the downhole systems is achieved. While this is not a simple initiative, many consider itto be a standard mode! for the future ofthe industry The details of subsystems followed by the challenges that must be overcome for development to proceed are described in the next sections. The Intelligent Well Alternative ‘As mentioned above, the intelligent well (shown in Fig. 1) includes a number of subsystems that, when designed and deployed properly, should result in a significant increase in economic benefits, These systems include downhole sensors, 270 surface reconfigurable flow controls, and a data telemetry system, Each of the subsystems deserves some discussion before the challenges that must be overcome can be addressed, Sensors. The sensors that are installed in the wellbore provide the starting point for the Intelligent well. Before a production process can be efficiently controlled, an accurate means by which to ascertain its parameters and measure them must be available For more than ten years, the industry has captured downhole pressure and temperature data. A traditional reservoir analysis is based on these parameters. These parameters are useful and important, but in and of themselves, are not able to convey the detailed information ied to make decisions concerning how a particular interval or formation should be managed. Flow rates and fluid constituents as well as near wellbore effects are required. Unfortunately, some of the transducers needed to convey this information are not currently available, and this demonstrates the industry-wide state of readiness. ‘Many operators are anxiously awaiting the availability of more advanced sensors because even a rudimentary economic analysis demonstrates the value that can be derived from use of these devices. A number of joint-development projects are underway for “4-D” seismic sensors and multi- phase flowmeters. Pressure and temperature sensors will Continue to be deployed as well because the information they supply will still provide value. Controls. Once a process can be accurately measured, controls that can be reconfigured to effectuate the desired changes are needed. At this time, the majority of the controls the industry uses are limited 10 slickline or coiled tubing ‘manipulation, and this is costly—particularly in a subsea well. The possibility of remote operation of these controls is primary focus within the industry today, and a few companies have already been able to provide some innovative solutions. With the heightened dedication to providing these solutions, this area will undoubtedly experience some significant technological advancement in the near future, Reconfiguring the production from a well without an intervention is the prime economic driver in subsea wells, and thus, any control that may enhance the long-term ‘maintainability of the well, minimizing the need for an intervention, is a welcome advancement. Telemetry, Some method for communicating with these downhole devices is required. At this time, the industry is limited to hard-wired systems, but considerable effort is presently underway to develop wircless systems. The data rates could become a significant challenge should a sensor be developed that would provide 3-D visualization of the in-situ fluids. Data compression techniques to enhance theSPE 38497 OVERCOMING THE CHALLENGES ASSOCIATED WITH THE Li "YCLE MANAGEMENT OF MULTILATERAL 3 WELLS: ASSESSING MOVES TOWARDS THE INTELLIGENT COMPLETION performance existing systems are under investigation, Surface Data Collection and Analysis. The surface data collection, analysis of the data, and command signal to effectuate the control of the well are areas that are largely overlooked in the Intelligent well arena. Many times the focus is on the downhole components, but the surface systems will have to play a significant role in the success of this initiative as well. In fact, production optimization techniques that have been applied to surface automation systems promise significant improvement in well ‘operations.** Asset Management. All of the aforementioned subsystems enable the operator to more effectively manage the asset, which after all is said and done, is the point to this entire initiative. Whereas in the current scenario, we make decisions about the optimum performance of a field from imperfect measurements and analyses, in the future, we hope to be able to enhance our decision making abilities because the data used to generate these decisions are more complete ‘and accurate and the controls are placed such that the asset can be drained more efficiently. The economic value of an oil producer and a unique solution for water management that entails downhole separation and re-injection are depicted in Figs. 2 and 3, respectively. Future Developments ‘The answer to the question, “Where do we go from here?” thas already been supplied through the announcement of a number of alliances. Since it would be overwheiming for even the largest of oilfield suppliers to be able to embrace the full scope of the intelligent-well initiative, it will only be through the formation of alliances and sharing of technology that the many necessary subsystems can be developed + Selecting the most appropriate technology Many of the technologies that must be considered to achieve these aggressive goals are not currently used in the oil and gas industry. And in most cases, there will be a multitude of options from which to choose. The ability to thoroughly evaluate the options, and then, from these evaluations determine the best technology to use for a particular application will become a very Important function, © Correctly applying the technology Because some of the technologies under consideration are not commonly used in our industry, care must be exercised when applying them in our aggressive downhole environments. In many cases, we will not have the luxury of thoroughly testing each concept. Risk management methodology will be required. And the delivery personnel will need to have a broader on understanding of the various enabling technologies that comprise a system. This will require specialized raining. © Challenges Many of the technologies that may be used to satisfy the requirements of this initiative are new to the oil industry, and this will require the alliance membership to include representatives from all targeted users. The application and coordination of the varied technologies as well as the development of these unique partnerships, will in themselves, present challenges. If the applications are too diverse or are not defined well enough 10 identify specific needs, challenges 10 the integration of the technologies will continue to surface. ‘* Understanding the needs of the industry I is very easy to become enmeshed in developing new technology. The thrill of breaking new ground in untested waters may divert our attention from the true Focus, which is to improve the control of the asset Frequent meetings to assess and align the goals of all who may be involved will be required. ‘The transfer of technical information related to the asset, and development of the specific technology being sought must be free flowing, These items have traditionally been held in strict secrecy, but for the most effective alignment of resources 10 take place, this information will have to be jointly managed through an alliance between the respective parties «Providing economic solutions None of the new technologies that may be developed will find a place in a well unless there is a good economic case for the benefits. While this is a simple statement, it will become increasingly difficult to evaluate the complex schemes that will be needed to address all aspects of a particular reservoir. ‘Applications Production optimization, profile control, water management and ultimately reservoir management, define the current thinking in applications for the intelligent well concept. Production optimization provides a primary example of its _usefuiness, Normally confined 10 artificial lift installations where the operating expense of the well may be effectively lowered by proper management of the production processes are excellent target wells for intelligent well technology. Most operators who use gas lift technology find improvements in the specific flowrates on the order of 10% are readily achievable. This is what many will expect the inelligent well systems to provide as a minimum. During the early years of this decade, a surface controllable electric gas lift valve was field tested in the Middle East,’ and this is an4 CLARKE, ROBISON SPE S897 excellent example of how this technology can be applied. Clearly, there are numerous flow controls that may be useful in intelligent wells — too many to list he Profile control systems are directed at long producing intervals as are typically found in horizontal wells. Although the reservoir is considered a homogeneous entity, the reality is that along a horizontal wellbore, the pressure may vary by 10 to 20 psi, and the permeability and porosity may differ enough to require some form of control along the entire length of the interval. The economic benefits from these installations are typically dependent on the inflow of gas or water, which is hard to generalize. To provide the degree of control that is required for these installations, some form of downhole choking will be required. Oil producer Fig. 4 depicts a proposed ‘standard’ “intelligent well” completion for a multizone oil producer. Each interval should be isolated for maximum control and a flow control should be placed between the packofts to allow the production from each interval to flow through the surface controllable flow device. ‘The flows from these intervals can be commingled by adjusting the flow controls to maximize the production, based on downhole pressure Downhole water separation/re-injection A number of companies are pursuing the separation and re-injection of water downhole. This was recognized in the early days as having excellent economic value. Fig. § charts the economic implications of one of these systems. In many areas, the existing topsides facilities are unable to manage any additional increase in water production, and this typically results in continuously declining oil rates. The capability to separate the water downhole and to dispose of it without lifting it to the surface will provide ample justification for installing prototype systems that are used to verify the concept and capture the costs and benefits. This is particularly the case when water facilities on the surface are no longer able to handle the volume of produced water, a common theme in many corners of the world. This is only conceivable from a multilateral well, Water management presumes that the operator must dispose of the produced ‘water, and typically, additional disposal wells are drilled and significant surface treatment facilities are a prerequisite When a fully functional system including surface computer processing to analyze the production data is deployed, not only on a ‘per well” basis but field wide, then the intelligent weil system becomes an effective tool for managing the reservoir. This is the ultimate goal of the intelligent well system. When an entire reservoir is monitored and production profile control is possible, then the sweep efficiency of the reservoir will be improved, and this will directly impact the recoverable reserve estimates. It is difficult to project an economic benefit when there are so many variables, but after modeling this improvement potential, some operators expect to achieve 20% improvement in the recoverable reserves. It is clear that a fully functional system as described would allow an operator to derive significant economic benefit. The complexity of these systems may detract from the potential benefits; however, the need to deploy an electric submersible pump with an anticipated life of twelve (12) months is another factor that could affect economical installations. Fig. 6 is an artis’s sketch of the primary areas targeted for inteligent well application. Conclusions Multilateral completion technology is a vehicle through which to surgically place drainholes in a reservoir, and the elligent well technology is the means through which the asset can be managed more effectively. When these two initiatives are successfully combined, the full benefit will ‘encompass and thus be greater than each of the individual parts. The industry will face some interesting challenges as these initiatives are fully developed. And as space age technology is applied downhole, the practicing engineer in all of us will finaly achieve fulfillment. Acknowledgments The author wishes 10 thank the management of Halliburton Energy Services for encouraging pursuit of this unique “Intelligent Well” concept, their total support in its development, and permission to publish this paper. References 1. Longbottom, J., Dale, D., Wadéell, K., Bruha, S., Roberts, Ju: “Development, Testing, and Field Case Histories of Multilateral Wells paper OTC8S37 1997 Offshore Technology Conference, 5-8 May 1997, Houston, Texas Harrison, D.. Grigsby, T.. Restarick, H. "Case Histories: New Horizontal Completion Designs Facilitate Development and Increase Production Capabilities in Sandstone Reservoirs, “Paper SPE 27890 presented at the SPE Western Regional Meeting, 23-25 March 1994, Long Beach 3. Perkins, D, Godttey.C., Plunkett, J. Olszewski K. “Development of a Safety and Production Automation System Usilizing Open-System Philosophy” SPE Paper No. 27237 Presented at the 2nd International Conference on Health, Safety & Environment in Oil & Gas Exploration /Production, Jakarta, 24-26 January 1994 4, Godftey,C., Perkins, D., Plunkett, J., Olszewski, K “Alternatives 10 Proprietary Systems For Safety and Production Automation,” SPE Paper No. 28805. Presented at the SPE 1994 Asia Pacific Oil & Gas Conference 7-10 November 1994, Melbourne 5. Schnatzmeyer, M.A., Yonker,J. Pool, M., Goiffon, J. “Development of a Surface-Controlled Electric Gas Lift Valve” SPE Paper No. 26553 presented a the 1994 European Production Operations Conference & Exhibition, 15-17 March 1994, in AberdeenRTU and Remote Telemetry System Hard-wired Downhole Telemetry ‘System, Downhole Control Valves with Integral Sensors Fig IA Basic Intelligent Well Completion Sytem 273Intelligent Well Economic Benefit Production Opti Upgraded Recovered Reserves [10% incremental improvement ‘Curnmulative Net OH MMB: . Year!) Your? Your vaard Youre Yoaruet, Net cam Cotes Boe cele Fig.2Chart showing economic beneft possible through production optimization with the “Intelligent Well” _ Nemo Ste natant ge Bares ne _ Wet Daina nit Fig. 3—Unique system for water management entaling downhole separation and reinjetion 274a ae gee Fig. & Depletion ofa proposed “standard” intelligent well completion fora maltione oll producer. Intelligent Well Economic Benefit Water Management System “| Watar Production WIO Dewnhéle Re‘njection ] 5 |_| (adaitionar Surtace FaciliiesRequiredto | | 7 Handle Water | + = ‘Adeitionel Recovered Reserves: 7 Beers! / fate ete] / ‘Cumulative Net Fluid MMB Years | Yearx | Yoartet [moun netwo eum aml a ‘Adv. Catrls ig, S—Graphically reflects the economic implications of the intcllgent well completion shoven in Figure 4 278276