Annular fracking, a case study of 4 vertical multistage wells in the lajas tight gas field
Zotskine, Youssouf Orlandi, Carlos
Annular fracking, a case study of 4 vertical multistage wells in the lajas tight gas field - 11 p.
The Lajas tight gas formation lies in the Neuquén Basin, located in the province of Neuquén, Argentina. The Lajas formation consists of more than 800 m of sandstone, heterolithic (interlaminated mudstones and sandstones), and mudstone deposits accumulated in different marginal marine setting. Vertical wells have been drilled and completed since the early phases of exploration and development of the field. Typical completions have called for using the Plug & Perf stimulation technique. This method of completion is not a true continuous operation method and obliges the operator to make multiple operational stoppages. In order to remain economical and avoid stimulating the individual clusters one after another, the plug and perf method forces a combination of intervals to be stimulated simultaneously. If the targeted zones have varying widths such as in the Lajas field this method does not allow for a customization of the design for each targeted entry point based on width of the target zone or its quality. In the search for uninterruptedness of operations and the ability to customize each lenses’ fracture design, the operator started considering other options for stimulating the wells in Lajas. Annular fracturing with packer isolation was considered as the proper way to allow both effective individual stimulation of clusters and customization of design. While annular fracturing has expanded significantly in North America in the last few years it has for the most part been applied in horizontal wells. Many challenges associated with its application in vertical wells had to be accounted for which were perhaps not necessarily considered in horizontal well designs. This paper discusses the application of annular fracturing in the Lajas field and its successful operational implementation in four wells. Well construction, technical challenges including coiled tubing and fracture design techniques had to be considered to make this completion successful. The operator has observed a significant cost reduction and operational efficiency increase as a result of this technique.
PD I116 3 0015570
Annular fracking, a case study of 4 vertical multistage wells in the lajas tight gas field - 11 p.
The Lajas tight gas formation lies in the Neuquén Basin, located in the province of Neuquén, Argentina. The Lajas formation consists of more than 800 m of sandstone, heterolithic (interlaminated mudstones and sandstones), and mudstone deposits accumulated in different marginal marine setting. Vertical wells have been drilled and completed since the early phases of exploration and development of the field. Typical completions have called for using the Plug & Perf stimulation technique. This method of completion is not a true continuous operation method and obliges the operator to make multiple operational stoppages. In order to remain economical and avoid stimulating the individual clusters one after another, the plug and perf method forces a combination of intervals to be stimulated simultaneously. If the targeted zones have varying widths such as in the Lajas field this method does not allow for a customization of the design for each targeted entry point based on width of the target zone or its quality. In the search for uninterruptedness of operations and the ability to customize each lenses’ fracture design, the operator started considering other options for stimulating the wells in Lajas. Annular fracturing with packer isolation was considered as the proper way to allow both effective individual stimulation of clusters and customization of design. While annular fracturing has expanded significantly in North America in the last few years it has for the most part been applied in horizontal wells. Many challenges associated with its application in vertical wells had to be accounted for which were perhaps not necessarily considered in horizontal well designs. This paper discusses the application of annular fracturing in the Lajas field and its successful operational implementation in four wells. Well construction, technical challenges including coiled tubing and fracture design techniques had to be considered to make this completion successful. The operator has observed a significant cost reduction and operational efficiency increase as a result of this technique.
PD I116 3 0015570
