Historically, horizontal wells in coal seam gas (CSG) producing areas of Australia have been limited in their ability to stimulate horizontal wellbores with hydraulic fractures, despite most basins being in favourable stress states capable of generating multiple transverse hydraulic fractures. In some cases, overlapping mining tenements limit the ability to effectively deploy steel casing completions to effectively manage multi-stage fracture stimulations along the lateral. In other cases, potential wellbore instabilities preclude the placement of laterals with adequate length to stage numerous fractures required to make a well economic. Strike Energy’s Jaws 1 well indicated well instability when drilling horizontally in the Patchawarra Vu Coal Seam in Petroleum Exploration Licence 96 of the Weena Trough in the Cooper Basin. To overcome this instability, Strike Energy introduced the application of an innovative process of deploying multiple, indirect hydraulic fractures in Jaws 1ST from a horizontal wellbore underlying the coal. Microseismic and surface deformation tiltmeter data acquired during the treatment confirmed the successful placement of fractures in the Patchawarra Vu Coal Seam. Further, chemical tracing and production testing provide further insight into the placement and effectiveness of the overall stimulation. Through analyses of data from the Jaws 1ST, we provide insight and recommendations regarding horizontal well placement to improve indirect hydraulic fracture effectiveness. These recommendations would be applicable for other Australian CSG basins where direct horizontal well drilling and fracture stimulation has been limited (e.g. overlapping mining tenements) or where horizontal well instabilities limit drilling within the seam (i.e. Cooper Basin, depleted coals).
Following technical success of vertical and deviated wells, Strike Energy audaciously continued to push the envelope while proving the commerciality of the deep coal seam play in PEL96. It was clear that extending the reservoir contact area of the wellbore and using innovative dewatering to significantly increase drainage was prudent. A horizontal well intercepting a vertical well coupled with multi-stage fracture stimulation was selected to achieve that goal. Furthermore, a new application of wide operating range electric submersible pumps would enable dewatering to much lower water rates to avoid running the pumps dry or damaging the fracture network upon gas desorption and breakthrough. Although a wellbore stability issue was encountered during the well construction phase, requiring a modified well trajectory, the horizontal well successfully intercepted the vertical well, reaching planned total measured depth. It also altered fracture stimulation approach to an indirect vertical fracture completion application, whereby fractures are initiated from the interburden layer below the coal seam. A million pounds of proppant was successfully placed in seven fracture stages. During the proppant pumping, diagnostic tools (tiltmeter and microseismic) and chemical tracers were utilised. The real-time microseismic confirmed the propagation of fracture from interburden upwards into the target coal seam. This presents the integration of well performance, subsurface information, past drilling practices and stimulation treatment results to support the decision-making process of a horizontal well construction and stimulation design as well as integration of real-time information to overcome operation difficulties and optimise well delivery. Tracer samplings and ongoing production testing during dewatering are also presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.