New Brunswick Canada's first commercial unconventional gas field, the McCully field, is located near the town of Sussex in southern New Brunswick. The field is comprised of low permeability Hiram Brook sandstones as well as the underlying Frederick Brook shale. The McCully field started producing gas from the Hiram Brook in April 2003 from two wells and was followed by full production in June 2007. Currently there are twenty-nine wells producing from the Hiram Brook. The Frederick Brook shale was placed on production in March 2008 and is producing gas from one hydraulically fractured vertical well. Additional wells have been drilled, hydraulically fractured and flow tested to further evaluate the development potential of the shale. Prior to 2009, development of the McCully field has included the use of water based hydraulic fracturing to enhance production. In 2009 a fracture program based on using LPG as the fracture fluid was undertaken. Both the Hiram Brook sands and the Frederick Brook shale have been hydraulically fractured with LPG and the results have been compared to the performance of the water based fractures performed in the past. It has been found that both clean up and initial well performance for these tight sands were significantly enhanced using LPG fracs rather than water fracs. This paper compares the clean up performance and the initial flow performance for wells fractured using the two fracturing methods.

The inherent advantages and limitations of drilling with coiled tubing have been the subject of many presentations in the last several years. The potential benefits that coiled tubing drilling systems offer have prompted development of several competing systems that are now being brought to the market. Although each of these approaches share some similarities, unique features have been introduced that enhance the value of the available systems. Full exploitation of coiled tubing drilling systems dictate that a practical approach be taken. Specifically, the most attractive approach is the one most highly leveraged to deriving the benefits offered by using coiled tubing. Because the coiled tubing drilling system is subject to limitations with respect to force delivery and the inability to rotate, the application of this emerging technology needs to be directed to a niche where it provides the operator best value. Coincident with the developments in coiled tubing drilling, industry's acceptance of underbalanced drilling techniques has been growing. It is now widely understood that the advantages of coiled tubing drilling are most evident in underbalanced operations. These advantages of technology will be applied to a wide range of well-finishing and reentry operations to increase both the productivity and recovery of hydrocarbons from existing fields. This paper presents the latest technology being applied in underbalanced coiled tubing drilling operations and highlights the additional advantages of using a pressure deployment system. Operations conducted in the first ten months of 1996 using these tools are reviewed. Introduction Over the last few years, the significant growth of underbalanced drilling in horizontal wells in Western Canada has created a significant opportunity for the use of coiled tubing. Development of directional drilling assemblies for coiled tubing has now opened up the market for coiled tubing drilling systems to be used for the drilling of horizontal wells while underbalanced. Coiled tubing drilling market segments in Canada have focused on niche applications. The specific market has been underbalanced drilling through the reservoir. The reason coil has been chosen to focus in on this particular market is coil's proven record of successfully operating in a live well environment and the operational and technical advantages coil offers while functioning in this these conditions. Coiled tubing is an excellent candidate for drilling if the well is to be drilled underbalanced. This is especially significant when drilling sour gas wells. The scope of this discussion will be focused on the Western Canadian market where coil is being used for underbalanced drilling. The paper will review the latest technology being used in coiled tubing directional drilling applications. Challenges that are inherent with this emerging technology and the unique solutions which have been employed to address and overcome these challenges will be discussed. In addition, a brief overview of the horizontal drilling jobs performed to date will be discussed. Underbalanced Drilling Underbalanced drilling (UBD) is generally considered to involve two phase fluid circulation (nitrified fluid) during drilling to lower the bottom hole pressure to below the reservoir pressure. UBD has become a widely recognized and viable alternative technique to conventional overbalanced drilling, which is especially advantageous in horizontal well drilling due to the increased time of formation exposure.