Hydraulic Fracturing Operations Enhancement in Depleted Horizontal Gas Wells, a Novel Approach with Outstanding Results

Abstract

Hydraulically fracturing operations is becoming much more complex as the gas formations are being depleted with the time. In addition to this, some gas reserves need to be recovered by fracturing horizontal wells with multiple stages which is the case of an extensive gas field in the Sultanate of Oman that has been producing since 1991 mainly by hydraulic fracturing. The scope of this paper is to discuss the different methodologies in the operations associated to hydraulic fracturing in horizontal gas wells with formations depleted in PDO, the main objective is to show operations and well delivery improvement by the optimization of tools conveyance, perforating techniques, clean out and milling strategy. The paper will show the enhancement of the operations and the outstanding results in these challenging well conditions. The paper will start by describing the different methods used to execute operations for fracturing horizontal wells which are mainly related to plug and perf technique, clean out and milling plugs in between stages. Further, it will discuss the strategy, planning and job execution of one of the wells with 14 stages in the horizontal section, the perforating technique and strategy used to help reduce screen out's, it will also discuss the acquisition of spectral Noise log data post fracturing with the assistance of Nitrogen as well as the milling of the isolation plugs at the end of the job. The optimization of the conventional operations is a novel approach to enhance hydraulic fracturing in depleted horizontal gas wells in PDO, this is in alignment with the continuous improvement ideas and the lean thinking across the oil and gas industry. It is easy to replicate in other horizontal wells to be hydraulically fractured which will reduce cost, HSE exposure and will help increase the recovery of hydrocarbon reserves.