Recent advances in horizontal drilling technology have allowed drilling longer horizontal sections in the reservoir more efficiently and economically. While operators benefit from the well-known advantages of horizontal drains, such benefits cannot be maximized during the lifetime of the well without a viable well intervention means for well service and monitoring operations. Coiled tubing has been recognized as an effective technique for such interventions but with limitation on the total length that can be accessed especially in extended reach wells. This paper summarizes the utilization of innovative coiled tubing Tractor technology to improve coiled tubing accessibility in long horizontal wells . Introduction The paper discusses the aspects of well intervention using coiled tubing (CT) and coiled tubing tractor technology on four (4) open hole horizontal water injection wells and one (1) cased hole oil producing well. The results presented show that the use of a coiled tubing Well Tractor combined with coiled tubing along with proper well selection, design and planning can result in a significant improvement in Well accessibility both in cased hole and open hole . Well Accessibility with Coiled Tubing For a well to be accessible with coiled tubing, the coiled tubing need to be run to the end of the horizontal section and no "lock-up" should happen before reaching TD. Lock-up occurs when no weight can be transmitted to the end of a coiled tubing and hence no progress into the horizontal section is possible. Coiled Tubing simulation software is available that can predict the depth at which this lockup is reached and whether it will occur. Such simulations are often used in the planning stage of a coiled tubing Intervention to decide on the type of coiled tubing pipe to be used (diameter and thickness). The following factors are taken into account in the simulation : Well trajectory, coiled tubing pipe variables (OD, thickness, strength, length), Diameter (s) in the wellbore, friction coefficients (cased/openhole), Well fluid type, temperature, pressure, and wellhead flowing conditions. Many techniques can enhance coiled tubing accessibility into the wellbore : The use of larger pipe, pipe straighteners, vibrating tools, pumping of Nitrogen, pumping of friction reducers or a combination of the above. A lot of literature has been published and is available about these techniques. Figure (1) shows coiled tubing Lockup depth using a typical output of a Well Intervention simulation program [refer to point A on the graph]. This is the "theoretical" Lockup point. Actual Lockup point can only be found when the coiled tubing is run into the hole. The advantage of using a coiled tubing Tractor at the end of coiled tubing is that it provides a concentrated downhole force that can delay or prevent lockup by "pulling "the coiled tubing from its end. This often results in improving well accessibility on extended reach wells. It is thought that when the CT locks up, a spiral type of form takes place at the end of the coiled tubing section; having a concentrated point load acting at the end of the coiled tubing will make this event unlikely thus improve the accessibility. Figure (1) shows the new lockup depth predicted by the well intervention Simulation program [refer to point B on the graph] after applying a concentrated force of 4000 lbs by the Tractor at the end of the coiled tubing as per the well intervention simulation.

Reservoirs with unstable formations or unable to sustain traditional cementing or other zonal isolation requirements may necessitate that additional external packers are incorporated. in the completion solution.Polymer-based packers are widely used in such cases as they are relatively uncomplicated to deploy, however, the degradeable polymers as such do also introduce an additional uncertainty and risk.The approach presented is based on a solid metal expandable system developed for the applications where inflatable external casing packers traditionally have been used. The well annular barrier provides long term robust and reliable zonal isolation in cemented or un-cemented completions and may also be used in conjunction with liners or long-string casing. Additionally it provides higher differential pressure capacity and higher expansion coefficients without compromising the inner diameter. Consequently it does not impair or restrict flow conditions and furthermore enables subsequent well maintenance to take place unhindered.The paper presents the development of a new solid metal expandable system for external casing applications and discusses the rationality behind the technology.

Having safe effective annular barriers that can be used for annular isolation is the key for managing wells. This has traditionally been done by either cementing the annulus or through the use of swellable packers.The use of cement as annular isolation usually is considered as the industry standard, however it is a complicated, time-consuming and expensive to deploy. Alternatives, such as polymer-based swellable packers, are usually less complicated to deploy, but the degradable polymers invoke a risk in the typically harsh environment of a well.The approach presented is based on a solid metal expandable system developed for the applications where swellable external casing packers traditionally have been used. The well annular barrier provides long term robust and reliable zonal isolation in cemented or un-cemented wellbores and may be used in conjunction with casing as well as liners. It also provides higher differential pressure capacity and higher expansion ratio to running OD without compromising the inner diameter. Consequently it does not impair or restrict flow conditions and furthermore enables subsequent well maintenance to take place unhindered.The paper presents the results of the development and testing of the new solid metal expandable system for external casing applications and discuss the rationality behind the technology as well as the experience gained.