In recent years, the formation known as the Bakken Shale in eastern Montana and western North Dakota has seen enormous growth in oil and gas production. Scientists from the United States Geological Survey have commented that the area has the potential to become "the next Saudi Arabia." In most cases, the Bakken horizontal wells are fracture stimulated. However, with several thousand feet of formation, effective stimulation of the entire length has proven time-consuming and costly. In the past, a single-leg zone was fractured all at the same time, regardless of the varied permeability of the layers. Although this simple method of stimulation was seen as a success at the time, a new, more efficient method using swellable packers with reactive elements now promises to optimize total recovery and minimize fracturing cost. Case history data will show how employing multiple frac sleeves with swellable packers straddling each interval proves to be a cost-effective way to stimulate multiple zones and save days of rig time. Specific experience in the Bakken field provides an optimization model for worldwide well completion markets Unlocking Tight Oil Traditional methods for tight oil drilling often include several costly steps to open up new veins: multiple downhole trips, cementing, plugging, perforating and finally fracturing. With the reactive-element packer method, the open-hole packers segregate multiple frac sleeves used to set up and designate multiple fractures on a horizontal wellbore. This segmenting process allows for more fractures, reduces the time and cost for hydraulic fracturing, accelerates production and improves reservoir drainage. In the Middle Bakken formation at the Sanish Field, North Dakota, an independent contractor sought a frac stimulation procedure to increase overall production while reducing well construction and completion costs. The contractor selected a successful recent innovation - reactive-element (swellable) packers - to perform an eight-stage compartmentalized frac job. Challenges The efficacy of frac stimulation is diminished when laterals exceed 5,000 ft. running an eight-stage frac job at more than 5,000 ft. involved even greater challenges. Major pumping investments are often required for tight shale formations. Traditional methods include pumping frac fluid into the open hole or isolating separate zones of a horizontal wellbore. The former method typically results in the frac fluid flowing to areas of least resistance, which can reduce production along the rest of the wellbore. The latter method typically includes several steps (repeated cementing, plugging, perforating and fracturing) and will also require multiple trips as well as the expense of additional crew and equipment for the duration of the operation. Completing high-angle wells also becomes problematic when getting tools through doglegs and other restrictions. The packers in the selected frac system are shorter than standard tools, which allow them to navigate better through such tight spots.

fax 01-972-952-9435. AbstractReactive element packers (REPs), sometimes referred to as swelling packers or self-energizing packers, offer a simple solution for multiple-zone open-hole completions. These packers are run into the well and begin to swell when they come into contact with various wellbore fluids, with the typical fluids of choice being water-or oil-based fluids. As the packers swell, they seal off the annulus between the liner/casing and the open-hole wellbore to provide isolation between zones with different pressures, or to simply shut off flow in the annulus and prevent migration of fines along the wellbore.As REP technology makes its mark in zonal isolation, application of the technology for fracturing and well stimulation is beginning to be explored. REPs used for frac'ing and stimulation offer a simplified method of breaking the desired zone into smaller sections without adding the cost and complexity that may result from using the traditional cement and perforating methods. This paper will discuss this new application for REPs. Functionality will be discussed, as will possible advantages and disadvantages of using the REP for well stimulation and fracturing. Key packer parameters will be reviewed to help demystify a seemingly infinite number of sizing possibilities. Then, initial testing to verify and validate the packer for this application will be discussed. Finally, this extensive test data will then be shown to validate a complex mathematical prediction model used to determine the REP's capabilities.

fax 01-972-952-9435. AbstractReactive element packers (REPs), sometimes referred to as swelling packers or self-energizing packers, offer a simple solution for multiple-zone open-hole completions. These packers are run into the well and begin to swell when they come into contact with various wellbore fluids, with the typical fluids of choice being water-or oil-based fluids. As the packers swell, they seal off the annulus between the liner/casing and the open-hole wellbore to provide isolation between zones with different pressures, or to simply shut off flow in the annulus and prevent migration of fines along the wellbore.As REP technology makes its mark in zonal isolation, application of the technology for fracturing and well stimulation is beginning to be explored. REPs used for frac'ing and stimulation offer a simplified method of breaking the desired zone into smaller sections without adding the cost and complexity that may result from using the traditional cement and perforating methods. This paper will discuss this new application for REPs. Functionality will be discussed, as will possible advantages and disadvantages of using the REP for well stimulation and fracturing. Key packer parameters will be reviewed to help demystify a seemingly infinite number of sizing possibilities. Then, initial testing to verify and validate the packer for this application will be discussed. Finally, this extensive test data will then be shown to validate a complex mathematical prediction model used to determine the REP's capabilities.

Due to the ever-increasing demand for oil and gas, it is becoming more evident that getting the most out of the reservoir is crucial. For years, wells were drilled vertical or deviated, but horizontal and extended-reach trajectories are gaining more prominence. While the objective is to gain more access to the reserves, often the past methods of completions simply were not viable. In deviated wellbores, cased and cemented liner applications are difficult to obtain a good cement bond with the formation, and the inherent near-wellbore damage associated with cementing can lead to costly workover and stimulation treatments. Thus, open-hole completions are becoming more acceptable as the primary completion of choice. This paper will discuss the benefits of gaining as much contact with the reservoir as possible to create maximum drainage. It also will cover completion solutions (turnkey) that have been deployed around the world to better optimize recovery. Case histories will be provided that include multi-stage fracturing with swellable packers, inflow control devices with mechanical-set packers, geothermal hook-ups with openhole anchor, and multilateral completions with sand control and zonal isolation. Introduction In today's oilfield it is important to gain the most contact with the reservoir to ensure the maximum drainage. Cutting-edge measurement-while-drilling (MWD) systems allow operators to accurately place the well within feet of the planned location. Often the well geometry will take a more horizontal profile in the producing interval because the payzones are tighter and shallower than wells of the past. In addition, one well can now be the conduit for many producing reservoirs with the use of multilateral completions. As the wells are becoming more complex and inherently more costly, it is important to simultaneously minimize risk and maximize recovery. The solution to all of these challenges is to complete an openhole production zone to eliminate any operational risk associated with cementing and perforation. No two wellbores are the same and with the growing advances in technology, openhole completions systems can be customized to meet operators' specific needs or demands. Completions may involve multi-stage fracturing using reactive element packers, inflow control with mechanical-set packers, multilateral completions with zonal isolation, and geothermal completions with openhole anchoring. Multi-Stage Fracturing With Reactive Element Packers One of the most versatile tools for providing zonal isolation is the reactive element packer (REP) which uses wellbore fluid exposure to activate and seal-off desired zones. The reactive element (sometimes referred to as swellable packers) is an easy alternative to other packers because they require no intervention to set. This further simplifies the completion phase and therefore reduces additional risk from pumping and running an inner string. In recent years this technology has been widely adopted for use in openhole multi-stage frac applications. When used in conjunction with ball-activated sliding sleeves (as seen in Figure 1), an entire horizontal section (with up to 12 stages) can be pumped continuously without the need to run bridge plugs.