practical uses of swellable packer technology to reduce water cut case studies from the middle east and other areas

1、Copyright 2007, Society of Petroleum Engineers This paper was prepared for presentation at Offshore Europe 2007 held in Aberdeen, Scotland, U.K., 4–7 September 2007. This paper was selected for presentation by an SPE Pr

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6、of where and by whom the paper was presented. Write Librarian, SPE, P.O. Box 833836, Richardson, Texas 75083-3836 U.S.A., fax 01-972-952-9435. Abstract Horizontal wells have become very common in the Middle East becau

7、se of their capability to increase reservoir contact, particularly in carbonate reservoirs. These types of formations often are naturally fractured, and because of channeling from underlying aquifers, allow the ingres

8、s of water into the production process systems. When water breaks through to the well completion, it tends to increase and becomes preferentially produced, thereby reducing the volume of produced hydrocarbons. This

9、phenomenon adds cost to the well operation because of the requirement to lift, separate, treat and dispose of the water. Preventing and managing water-cut through cementing, chemical application or the use of mechan

10、ical openhole barriers such as inflatable packers is costly, and often, the method chosen is not effective. This paper will discuss the use of swellable packers to provide a long-term, completely effective, water shu

11、toff tool. These packers use expanding rubber around the packer that expands to seal the annulus. When expanded, a permanent seal is created, regardless of whether the packer has been run as a straddle or as a plug

12、. The packers can be used in open and cased-hole applications in all the most common oil- and gas-well environments. This paper discusses the development and design of the packer and presents case histories from the

13、 Middle East and other parts of the world that illustrate the advantages that swellable packer technology can provide to operators in reservoirs in which water break-through has been predicted or experienced. In t

14、hese case histories, it will be shown that the packers significantly reduced water cut, which in turn, reduced water disposal costs and intervention needs while increasing production rates and extending field life. Re

15、servoir Challenges Major oil companies worldwide continue to evaluate new technologies to ensure that their strategic resources are optimally explored, developed, and efficiently produced during the life of their o

16、il and gas fields. Abu Dhabi National Oil Company (ADNOC) along with its group of subsidiary companies are among the companies that continue to pursue innovative technologies. The actual adopting of a new technolog

17、y varies considerably between different operating companies with the early adopters being more willing to take risks if it means that the investigated methodologies could prove to offer greater advantages to productio

18、n scenarios. Since the swellable packer has shown success in many different applications, its acceptance has been accelerated. The exponential growth in usage of the swellable packer is shown in Figure 1. Managemen

19、t of produced water has been a major challenge in the ADNOC and other operator wells in much of the Middle Eastern area. Water cut in new and existing production wells is undesirable, and in many cases, leads to incr

20、eased operating costs to dispose of the water, expensive remedial treatments, environmental issues related to disposal, and the premature shut in of the wells. This often leaves oil in place that may never be produce

21、d. In the last twenty years, step changes in the capability to deliver accurately placed long horizontals have proven extremely beneficial to many operators of carbonate reservoirs worldwide. Natural and drilling-b

22、ased faulting and fractures in these formations are relatively common, and water from other nearby formations will use these channels to break through to the production string, significantly reducing oil production.

23、Operators worldwide have used multiple technologies to try strategies that can combat “bad” water; i.e., water that does not add to net oil produced. Chemical methods have proven effective in targeting longer sections

24、 where the gels and polymers can be placed deeper into the formations. Fractures and faults typically have been targeted with mechanical isolation methods such as bridge plugs and inflatable packers. This paper disc

25、usses a newly developed technology, swellable packers, and uses case histories from the Middle East and other regions to describe their use to improve the reliability and deployment of mechanical water shutoff method

26、s. SPE 108613 Practical Uses of Swellable Packer Technology To Reduce Water Cut: Case Studies From the Middle East and Other Areas Ashraf Keshka, Abdalla Elbarbay, and Cherif Menasria, Abu Dhabi Company for Onshore Oi

27、l Operations, and Pete Smith, Halliburton SPE 108613 3 The simplicity of the swellable-packer design offered the advantage of flexibility since the thread connections of all items were the same; allowing for the ‘spa

28、cing out’ of the swellable packers and the screens where the sequence of oil sands was interrupted by water and gas sands. The packers provided significant cost savings plus the flexibility concerning the actual wel

29、l construction that other approaches could not offer. The packers were spaced out with the screens, while blank pipe and pre-perforated liners were hung off a liner-hanger packer in the casing above the open hole. T

30、he packers were swollen using produced oil. Surface measurements showed that water cut dropped off from near 100% to 0% in less than three weeks. In addition to the advantage of significant savings in well constructi

31、on costs, the use of the swellable packers supported an incremental increase in production through reduced skin and the savings gained by avoiding cementation and perforation damage.2 Case Study 5 An oil productio

32、n well in a mature field in the UAE was to be completed using swellable packers as zonal isolation mechanisms to reduce expected water cut. The packers were run, and the well placed on production. After a relatively s

33、hort time, rubber was found on surface in addition to increasing water cut. One theory proposed was that the packer or packers had been damaged while they were being run through the window. Considerable testing of pa

34、ckers that were run through actual windows in surface simulations as well as in extensive field runs had shown that this phenomenon was unlikely, since swellable packers had shown advantages over all other types of p

35、ackers in situations where damage could occur. These advantages were attributed to the swellable packer’s inherent capability to self heal. Correctly placed packers in the same field had shown very successful water-c

36、ut reduction. Subsequent analysis showed that the upper isolation packer appeared to have been placed in the waterfront zone rather than above it, and this placement had compromised the expected results. Additional

37、 Scenarios for Swellable Packers Although the swellable packers discussed in these case histories were used in more traditional completion scenarios, swellable packers have been used successfully in other types of co

38、mpletions and workovers as well. These are discussed in the following paragraphs. Underbalanced Drilling. Underbalanced drilling (UBD) has proven that it can add value to many of the types of well operations because

39、 of the improvements it makes to the Productivity Index (PI). These improvements can be attributed to the reduction in wellbore matrix damage. Swellable packers are particularly suited for use in UBD completion condit

40、ions due to the fact that no pressure needs to be applied to achieve a seal, a situation which can be challenging where well-fluid levels may not be accurately known. In addition, there is considerably more flexibili

41、ty regarding wellbore ID compared with stand-alone solid expandable tubulars (SETs). SETs have been tried as mechanical isolation devices, but became less effective as changes from the original borehole ID occurred.

42、 However, when swelling elastomers were combined with SETs, considerable success was noted.3,4 Heavy Oil. Another particularly effective use of these packers for water shutoff is in heavy oil applications where it i

43、s considered extremely desirable to reduce the harmful effects of produced solids, which are given mobility by water/oil emulsions. Reservoir compartmentalization has been shown to reduce the production of solids and

44、fines through lower annular velocities.5 Intelligent Wells. The capability to monitor reservoir activity and to selectively and actively modify or shut off production from particular wellbore sections is an obvious

45、advantage. The technology to enable this has gone through much development in the last ten years and is considered a reliable and valuable part of the reservoir management toolkit. Swellable packers, which permit al

46、l of the advantages of reservoir compartmentalisation with the monitoring and flow modification of intelligent wells, have been developed for openhole completions. These packers have a unique advantage over other typ

47、es of packers since they eliminate the unreliable and time consuming splicing necessary with other packers.6 The control lines and flatpacks are fed through a preformed slot in the rubber element as the packer is

48、run through the rotary table. (Figure 7). Inflow Control and Reservoir Management. Horizontal well configurations have proven to be beneficial in maximizing production through increased reservoir contact and by del

49、aying coning and water/gas breakthrough. However, these benefits can be negated due to the friction effect from fluid production in heterogeneous reservoirs or where permeability varies. The use of inflow control devi

50、ces (ICDs) in recent years has mitigated these adverse effects, but their use requires effective openhole compartmentalization. Swellable packers are becoming the preferred choice of mechanical devices for such a

51、pplications due to their simplicity of deployment and their operation as well as their long-term reliability. Cased-Hole Workovers. Water shutoffs using swellable packers have been performed as part of workover progr

52、ams in existing wells. Typically, these will be run as straddles, but they can also be used as single packers acting as plugs. Deployment may be on the tubing string recompletion or on a workstring. Tools capable of

53、running these packers riglessly using coiled tubing, electric line, or slickline also are available. Limitations and Lessons Learned Testing. By their nature, swellable packers do not form an instant barrier, and th

54、erefore, it is obvious that whether the tools are run as part of a segmented openhole completion string on tubing or are deployed as a drop-off plug or straddle, there will be a delay in testing the packers. Because o