Innovative Method of Gas Shale Well Intervention with Coiled Tubing/Jointed Tubing Hybrid String

Abstract

As the industry strives to maximize production in US shale plays, the number of extended-reach horizontal wells being drilled continues to increase in efforts to optimize reservoir contact and increase fracture intensity. Because operators demand the same level of performance achieved on shallower wells while providing a cost-effective and safe solution, these wells present complex challenges for completion and intervention operations. Coiled tubing (CT) enables an efficient means to deploy tools and perform pumping operations, such as drilling out plugs, wellbore solids cleanout, and matrix or fracture stimulation in a continuous manner. In any well-intervention operation, the CT size is maximized to achieve the desired level of operational efficiency and effectiveness. To reach the target depth of these extended-reach wells, smaller CT must be used because reel capacity is limited. This not only limits the pump rate that can be achieved, but smaller CT is more susceptible to helical lockup and could require costly assistance to achieve depth. Also, many roadway authorities have established size and weight restrictions that can dictate the size of CT used. A new hybrid solution is now being used to combine the benefits of both CT and jointed tubing (JT) in a single work string. The solution presents many cost benefits while extending the depth of reach that can be accomplished to perform continuous-pumping operations using the optimum diameter tubing and pipe. The system incorporates unique well-control tools that enable seamless functioning of the string in a live well, thus providing considerable time and cost savings. This paper presents the benefits of the hybrid unit and discusses the enabling technology while providing an overview of field trials of multizone stimulation treatments in the Bakken and Marcellus reservoirs.

Development on coiled tubing fracturing sleeve for shale gas horizontal well

“…For the first method, [3][4][5] the drilling plug technology is needed to be performed which leads to the increases in operation time and risk, and the process usually adopts hydraulic fracturing and jet perforation, so it is complex. For the second method, 6,7 it is usually a single process: once we want to close a sliding sleeve in certain level for selective production, the special tool is needed to put into the borehole, which results in complex processes.…”

“…Researching a large number of the current fracturing cases 1,2 of shale gas horizontal well, two methods are commonly used: one is cable perforation and pumping bridge plug (referred to here as plug-and-perforate) and the other is opening the fracturing sliding sleeve by dropping-down balls with different sizes in proper order (referred to here as BDFS). For the first method, [3][4][5] the drilling plug technology is needed to be performed which leads to the increases in operation time and risk, and the process usually adopts hydraulic fracturing and jet perforation, so it is complex. For the second method, 6,7 it is usually a single process: once we want to close a sliding sleeve in certain level for selective production, the special tool is needed to put into the borehole, which results in complex processes.…”