Interference testing with horizontal wells in layered reservoirs

Abstract

Interference testing between horizontal wells has beoome a wimble tool in characterization cf heterogeneous reservoirs. However, he ament methods cf analyzing the interference testing between horizontal wells using sirrfe layer homogeneous model for heterogeneous system like layeredformation can result in errors in the estimated average reservoir properties. This work presents a study cf doe effect cf layering on the response at the observation well in horizontal well interference testing in a two-layer reservoir, and the error caused by estimating the reservoir parameters using a single layer analytical model A numerical approach is errpkyedto study the effect cfp arameters like omsgz &, kappa k , vertical permeability and distance between the horizontal wells on observation well response in an interference testing with horizontal wdls in a two-layer reservoir. The results cf the study show that in an interference testing in a two-layer reservoir, observation well pressure response deviates from equivalent sirrfe layer system response This deviation depends on the contrast cf transmissibility and storage between the two layers. The deviation is most pronouncedf or small co andlargp k. However, as the distance between the wdls increases, the deviation cf the observation wdl response from the equhdent sinrfe layer system response decreases. If doe contrast in transmissibility and storage between the layers is large, the vertical permeability has considerable effect on doe observation wdl response It teas also found that, when analyzing interference test data conducted ina two-layered reservoirf or long duration, assuming sinrfe layer model, the error in estimated transmissibility is low and in estimated storage is large. However, for short duration test, errors in both transmissibility andstoragp can be very hifo.