Interpreting Uncemented Multistage Hydraulic-Fracturing Completion Effectiveness By Use of Fiber-Optic DTS Injection Data

Abstract

Summary Tight gas, low-permeability reservoirs offer a tremendous challenge with respect to effectively completing and draining a target reservoir. Openhole-packer completions in horizontal wells offer a cost-efficient means of accessing the entire lateral section, assuming the target pay can be effectively stimulated. The challenge with openhole completions compared with more-conventional cased, cemented, and limited-entry perforated completions is understanding and controlling hydraulic-fracture geometry—specifically, the number and location of fracture-initiation points and the fracturing-fluid flow into the near-wellbore (NWB) region of the reservoir. Fiber-optic-based distributed temperature sensing (DTS) offers a method for identifying, quantifying, and evaluating the NWB fracture geometry, the fracturing-fluid distribution in these broad openhole sections, and overall stimulation effectiveness. DTS can also reveal success or issues with respect to effective zonal isolation when using mechanical isolation during the hydraulic-fracturing process. In this particular case study, a lateral well in a basin-centered gas area was completed with swell-packer interval isolation by use of fracture sleeves for reservoir access. By coupling fracture-treatment responses and openhole log characteristics with the NWB DTS data during pumping and warm back, an integrated assessment of the completion stimulation effectiveness and efficiency was performed. The end result of this assessment provided an improved understanding of the current completion performance and allowed optimization of openhole completion projects for future wells in this same area.

Advancement of Hydraulic Fracture Diagnostics in Unconventional Formations

“…DTS has also been used in assessing production from fractured wells during production [39]. Holley et al [40] described the specific application of DTS in open hole packer completion for a tight gas reservoir. With the challenge of low permeability in tight gas reservoirs, the open hole completion is expected to provide greater access to the reservoir.…”

Wellbore Cool Down During Hydraulic Fracturing Simplifies Using Dissolvable Materials

“…During acid stimulation, distributed fiber-optic measurements have demonstrated the cooling effect of the injected fluid [7] and have used this distributed measurement to determine where the acid is entering the formation [8,9]. Similarly, distributed fibre optics has been used to describe the cooling effects during hydraulic fracturing [10,11]. Most of these temperature diagnostics have been used to determine how the formation is accepting the injected fluids [12].…”

Temperature Prediction Model for Two-Phase Flow Multistage Fractured Horizontal Well in Tight Oil Reservoir

“…In recent years, distributed temperature sensing (DTS) has been gradually used in downhole temperature monitoring. DTS provides continuous temperature profile data of fractured horizontal wells, and inversion of the measured data can interpret the fracture contribution and parameters [4,5]. DTS has high temperature resolution, which can reach 0.01°C, so small temperature changes in the wellbore can be detected [6].…”