Optimizing Openhole Completion Techniques for Horizontal Foam-Drilled Wells

Abstract

Over the last two years the increase in openhole interventionless horizontal completions in the shale markets has lead to higher production rates at lower completion costs for operators. In areas where wells are being air-drilled, specific techniques of using hydraulic set packers and sliding sleeves has proven to be a viable, low-cost, interventionless solution to complete when the wells are likely to be a gauge hole. However, in areas where the horizontal wells use foam instead of air because of the sensitivity of the shale, typically the wellbore is non-gauged and may lead to operational failures when trying to isolate the wellbore with hydraulic set packers because of the limitation of the expansion of the element package. The advances in the use of swellable elastomer packers provide an ideal solution for isolating these non-gauged holes for the completion process. But, as mentioned, there is sensitivity to the shale in these wellbores, and applying the typical hydrocarbon fluid to the formation to swell the swellable elastomer packers may cause a detrimental effect to the formation. To overcome the issue of isolation in non-gauged holes without damaging the shale formation, an interventionless solution was incorporated using sliding sleeves, swellable elastomer packers, and development of a new shale optimized fluid system to swell the packers. The shale-optimized fluid is an effective low-leakoff fluid that causes minimum physio-chemical damage to the shale while increasing the optimization of the swell time of the packers. This paper will discuss the development of this new completion process for use with foam-drilled openholes that are non-gauged and case history information of applications that have been run in the Lower Huron shale formation. Introduction In recent years, the North American land markets have seen a shift in focus towards developing gas shale plays such as the Lower Huron, Marcellus, and the Haynesville formations. This shift can largely be attributed to the development of new technologies that make the completion costs more economical. One of the technologies that has made a big impact on lowering completion costs is the combination of horizontal drilling and the use of sliding sleeve technology to provide an interventionless completion. The deployment of this type of system enables the operator to separately frac several different intervals within the horizontal section without shutting the pumps down. Operators can simply drop a ball from surface to isolate the intervals that have been treated and open the next zone for treatment. This cuts the completion time down by removing the downtime associated with running perforation guns and setting plugs. This type of completion also maximizes production possibilities by optimizing and tailoring treatments for each interval throughout the full horizontal section of the wellbore. To compartmentalize the horizontal section and optimize the fracture treatments, zonal isolation is required in the annulus in between each sliding sleeve. There are several ways to establish zonal isolation including traditional cement, openhole hydraulic set packers, or inflatable packers, but each method adds a certain complexity whether by adding operations to complete the installation or introducing more mechanical components, which increases the risks associated with installation. The introduction of swellable elastomer packers (SEPs) as the method of zonal isolation greatly simplifies the installation process and decreases the associated risks. SEPs are simply positioned onto the production casing and spaced out as per the wellbore plan. Once in position, the swelling activator, traditionally liquid hydrocarbons, natural gas, or water is introduced into the system allowing the SEPs to begin to swell. Once activated, the swellable elastomer packers will continue to swell and conform to the wellbore ID in which they are installed.

Effect of the number and length of zonal isolations on pressure behaviour of horizontal wells

“…As a result, it has been used in recent years, especially in the shale layers where it has led also to higher production rates (Allison et al, 2009). An open-hole horizontal well completion may cost less than other types of completion.…”

Investigation of Pre- and Post-Swelling Behavior of Elastomeric Material

“…Swelling elastomer sections can be deployed to segment horizontal wells, thereby shutting off unwanted water and gas, and can thus increase recovery from mature reservoirs (Tejas 2009;Al-Mahrooqi 2007). Successful applications of swelling elastomers include cementless completions (Rogers 2008;Nylund 2010), well completion together with cement jobs (Cooper 2008), zonal isolation in open-hole completion of foam-drilled horizontal wells (Allison 2009), etc.…”