Use of Interference Tests to Constrain the Spacing of Hydraulically Fractured Wells in Neuquen Shale Oil Reservoirs

Abstract

Abstract Well spacing is a key factor in the evaluation of pad economics for hydraulically fractured horizontal wells. The drilling at the wrong well spacing leads to either over-capitalization risk or leaving reserves in the ground both resulting in loss of net present value risk. This paper presents data acquisition techniques that aid in well interference identification and quantification. Integrated analysis of data from a well pad in the Vaca Muerta formation, including microseismic, chemical tracers, geochemical fingerprinting, and pressure measurement, indicates both pressure and production communication between the two wells studied. Then a dedicated interference test is designed and analyzed to provide insights on well spacing. The test consists of alternating shut-in periods of the two wells during which pressure and rate are closely monitored. Analytical and modeling work has quantified the degree of interference to be up to 20% on production rates. This interference test is performed between two ‘semi-confined’ wells. Future multi-well pads are planned to understand the production potential of a fully ‘confined’ well and the interference between neighboring wells, to further understand the well spacing and pad economics.