Latest Developments using Fiber Optic Based Well Surveillance such as Distributed Acoustic Sensing (DAS) for Downhole Production and Injection Profiling

Abstract

In the past decade, Fiber-Optic (FO) based sensing has opened up opportunities for in-well reservoir surveillance in the oil and gas industry. Distributed Temperature Sensing (DTS) has been used in applications such as steam front monitoring in thermal EOR and injection conformance monitoring in waterflood projects using (improved) warmback analysis and FO based pressure gauges are deployed commonly. In recent years 1 significant progress has also been made to mature other, new FO based surveillance methods such as the application of Distributed Strain Sensing (DSS) for monitoring reservoir compaction and well deformation, multidrop Distributed Pressure Sensing (DPS) for fluid level determination, and Distributed Acoustic Sensing (DAS) for geophysical and production/injection profiling. For the latter application, numerous field surveys were conducted to develop the evaluation algorithms or workflows which convert the DAS noise recordings into flow rates from individual zones. The applicability of a new graphical user-interface has been expanded to include smart producers and injectors that allows the user to visualize (in real time), QC and evaluate the DAS data. Also, the evaluation methods for the use of DTS for warmback analysis have been significantly improved.There are still improvements to be made in enabling Distributed Sensing infrastructure, such as handling and evaluation of very large data volumes, seamless FO data transfer, the robustness & cost of the FO system installation in subsea installations, and the overall integration of FO surveillance into traditional workflows. It will take some time before all these issues are addressed but we believe that FO based applications will play a key role in future well and reservoir surveillance.In this paper we present a recent example of single-phase flow profiling using DAS. The example is from a long horizontal, smart polymer injector operated by Petroleum Development Oman (PDO).

Distributed Fiber Optic Vibration Signal Logging Well Production Fluid Profile Interpretation Method Research

“…An important way to monitor the dynamics of oil and gas field development is to measure the fluid flow profiles in oil recovery wells and water injection wells. The purpose of the measurement is to understand the nature and flow rate of the produced or inhaled fluid in the production well section and to make an evaluation of the production status of the well and the production properties of the formation [1][2][3][4][5]. However, in the actual oil and gas field development process, although one can know the total amount of produced oil, gas, and water, it is difficult to determine the contribution of each shot hole section stratification to the output [6].…”

Estimation of Temperature Profiles using Low-Frequency Distributed Acoustic Sensing from In-Well Measurements

“…DAS systems are sensitive to changes in temperature. These variations can be monitored during a variety of operational processes including hydraulic fracture monitoring (Bakku et al, 2014;Karrenbach et al, 2017), microseismic event detection (Metsayer et al, 2011;Webster et al, 2013), production/injection profiling (Horst et al 2015), well integrity monitoring (Raab et al 2019), gas-lift optimization (Koelman et al 2012), geomechanical modelling (Sherman et al 2019) and recording of multiphase flow measurements (Fidaner et al 2017). Distributed Temperature Sensing (DTS) systems are also commonly deployed in wells, as to which the measurements are similarly affected by variations in temperature.…”