The focus of the international oilfield industry is clearly increasing toward the development of unconventional plays worldwide, and this increased focus is evident in the development of local shale formations in the Neuquén basin. The emerging unconventional market in western Argentina constitutes most of the drilling operations in the region.

Well integrity is a key requirement for these projects that demand distinctive completions through massive hydraulic fracturing. Existing conditions within the field add major challenges to the overall well construction process, considering the high pore pressure and the ultranarrow operative window (i.e., tight pore-fracture margin) present along the production section. These conditions increase the demand for dynamic pressure management techniques.

Shale-targeted wells were cemented overbalanced at first; however, the failure rate was high, leading to annular pressure buildup (APB) problems requiring costly remediation. Some wells could not even reach total depth (TD) and were temporarily abandoned. Presently, most of the unconventional wells drilled in the area are cemented using a managed pressure cementing (MPC) technique, which has considerably improved the success rate. After defining critical anchor points, an engineering design methodology is proposed to adjust a dynamic backpressure profile to effectively control the formers.

Considering the APB rate as the evaluation criteria in place, this engineering approach has made cement placement in local unconventional wells more effective than ever before, increasing the success rate from approximately 67% in 2013 to nearly 95% in Q1-2015.

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