HOME >  Oil and Natural Gas >  Technology development >  Reservoir monitoring

Reservoir monitoring

  • Share
Monitoring the behavior of hydrocarbons and/or injected fluids, such as CO2 or steam, inside subsurface reservoirs is crucial for implementing efficient and effective enhanced oil recovery (EOR). Therefore, Japan Organization for Metals and Energy Security (JOGMEC) aims to establish an integrated reservoir monitoring technique that utilizes geophysical methods (such as seismic surveying techniques), with direct application in the field.

Figure: An image of Reservoir Monitoring

Monitoring using a Highly Repeatable Seismic Source

When monitoring the small changes caused by fluid movements in the physical properties of a reservoir, the reproductivity of a seismic source is a significant factor. Therefore, JOGMEC is developing a monitoring technique based on accurately controlled routine-operated seismic source (ACROSS) with high reproductivity.

Accurately Controlled Routine-Operated Seismic Source (ACROSS)

The ACROSS system is a fixed vibrator on the ground that can repeatedly transmit seismic waves by rotating an eccentric weight in a high-accuracy manner. Note that JOGMEC is conducting a study on a monitoring technique and developing a field demonstration test using ACROSS.

Figure: An image of monitoring by a Across vibrator

Demonstration Test for ACROSS at Aquistore CCS Project in Canada

The Aquistore Project is a world-leading carbon capture and storage (CCS) project at Saskachewan in Canada; JOGMEC is conducting a demonstration test of ACROSS at this site, in collaboration with the Petroleum Technology Research Centre (PTRC) in Canada. At present, to understand the changes in the physical properties caused by CO2 injection into the ground, JOGMEC is acquiring data and developing an optimum analytical technique.

Figure: Monitoring setup designed by JOGMEC.

Monitoring Technology using Distributed Acoustic Sensing (DAS)

JOGMEC is developing a monitoring technology using distributed acoustic sensing (DAS); this technology is garnering increasing attention in the industry as a seismic receiver system that can be used for long-term monitoring with low cost.

Distributed Acoustic Sensing (DAS)

JOGMEC is developing a reservoir monitoring technology at the Aquistore Project (Canada) that combines ACROSS and DAS. We compared the DAS data acquired via a baseline survey in 2016 and a monitoring survey in 2018; the difference between the two datasets was small, indicating that the repeatability between the two datasets acquired by the ACROSS and DAS systems was high.

In 2019, JOGMEC, in collaboration with the U.S. Department of Energy’s National Energy Technology Laboratory (NETL), successfully applied full waveform inversion (FWI) to DAS data acquired from a well in onshore Alaska. This effort allowed JOGMEC to accurately reproduce the vertical trend of subsurface P-wave velocity structures by using FWI, a cutting-edge computational method, enabling the precise evaluation of velocity models.

In the future, JOGMEC aims to develop an efficient and long-term monitoring technique by accumulating knowledge from a demonstration test of a monitoring system equipped with DAS systems.

  • Figure: Comparison between waveform data acquired from baseline and monitoring surveys using ACROSS and DAS.
    (A difference deeper than 1.2 seconds can be attributed to the difference in the recording timing.)

  • Figure: Results of FWI analysis conducted using DAS data of a well onshore Alaska.
    (a) Shot gather recorded with DAS;
    (b) P-wave velocity (Vp) model before FWI application;
    (c) P-wave velocity model after FWI application;
    (d) comparison of the data to the sonic log data acquired from the well
    [light blue: records of sonic log, red: P-wave velocity model before FWI, blue: P-wave velocity model after FWI]

Advanced Reservoir Imaging Technique

JOGMEC is developing a high-resolution imaging technique for reservoirs.

Elastic Full Waveform Inversion (FWI)

Acoustic FWI may cause significant analytical errors when the acoustic wave equation only described the propagation of P-waves which mismatches against real wavefields.
This mismatch would be significant if the S waves are dominant, owing to the usage of a direction-dependent seismic source or the existence of guide waves. Therefore, JOGMEC is conducting a research on elastic FWI based on the wave equation, while considering both P and S waves.

At present, JOGMEC has successfully imaged the changes in the physical properties induced by CO2 injected in reservoirs, by applying elastic FWI to the time-lapse crosswell seismic data acquired at a CCS testing site in Nagaoka, Japan. In the future, JOGMEC will continue monitoring the fluid behavior in the subsurface using FWI.

Figure: Comparison of the results of the elastic FWI analysis and acoustic well-logging:
(a) velocity profile at OB3; (b) analytic P-wave velocity model;
(c) velocity profile at IW1; (d)velocity profile at OB2.
Abbreviations: velocity of P wave (Vp）

Japan Organization for Metals and Energy Security
(JCN 4010405009573)

Toranomon Twin Building 2-10-1 Toranomon, Minato-ku, Tokyo 105-0001, JAPAN
Tel : +81-3-6758-8000

Copyright© Japan Organization for Metals and Energy Security All Rights Reserved.