Abstract
Gas object T is characterized by poor reservoir properties and high horizontal and vertical heterogeneity. Therefore, the development of this reservoir is economically unfeasible with the conventional technologies of production applied to the majority of gas fields in Russia. Besides, by the beginning of the welltests this gas deposit had not been in production.
In order to ensure a deeper assessment of the target reservoir and work out robust engineering decisions, a Target Innovative Project under the title Selection of the development technology for the Turonian low-permeability gas deposit was carried out by Rosneft from 2012 to 2014. Under the pilot project, three different production wells were drilled: a vertical well with a hydraulic fracture (HF), a horizontal well completed with a slot-hole filter, and a horizontal well with a three-stage HF assembly.
This paper discussed the results of field welltests in a low-permeability gas reservoir characterized by high heterogeneity. The welltests were carried out in wells with different completions, estimates were received, and comparison of productivities performed. The paper also discusses the assessment of solid particle sloughing and validates a maximum pressure drawdown for the target reservoir. Pressure-transient tests enabled estimating the permeability of the reservoir, the effective length of the non-HF horizontal well (HW), the parameters of fractures in the vertical HF well and the horizontal three-stage HF well. Effects of nonlinear flow in wells with various completions are considered.
The paper also demonstrates the results of an interference test. This test confirms the existence of hydrodynamic connection between the pilot wells in the target low-permeability gas reservoir.
