The Potential Role of Passive Seismic Monitoring for Real-Time 4D Reservoir Characterization

Abstract

This paper details the application of passive seismic monitoring to image reservoir fracturing and deformation from the stage of an initial well completion to final field production. Instrumented oil fields with seismic arrays either permanently installed or temporarily deployed on wireline offer the possibility of imaging production activities in a real-time sense that complements other seismic reflection and engineering measurements. During the wellcompletion stage of development, real-time microseismic imaging offers the possibility of monitoring well stimulation. Fracture images may be used to optimize the fracture design and the net present value (NPV) of well production, as well as understand fracture complexity and the associated well-drainage pattern to target future well placement. During production stages, time-lapse microseismic imaging may be used for image deformation associated with fracturing or fracture reactivation from pressure or stress changes, strains in the overburden in fields with casingdeformation problems, and image fronts associated with secondary recovery. In this paper, several case studies are used to illustrate various potential applications, along with discussion of the potential limitations. The reservoir conditions necessary for the success ful application of the technology are presented along with a potential method to quantify the technical feasibility at a particular site.

Influence of a velocity model and source frequency on microseismic waveforms: some implications for microseismic locations

“…Hence, over the past couple of decades, microseismic monitoring has become increasingly common in the hydrocarbon industry as a tool to investigate production related geomechanical deformation (such as subsidence, e.g. Dyer et al, 1999) as well as audit hydraulic fracture stimulation treatments (e.g., Maxwell and Urbancic, 2005). Waveform attributes, such as amplitude and polarity, can be used to invert for the failure mechanisms (e.g., moment tensors) of both pre-existing and newly generated fractures or fracture systems (e.g., Baig and Urbancic, 2010), as well as evaluate the fracture stimulation program (e.g., Baig et al, 2011).…”

“…Monitoring the distribution of microseismic attributes (e.g., event location and source mechanism) in space and in time provides insight into the spatial and temporal variations in the stress field and is commonly used to delineate activity on pre-existing faults and joint systems as well as identify their orientation and density. Hence, over the past couple of decades, microseismic monitoring has become increasingly common in the hydrocarbon industry as a tool to investigate production related geomechanical deformation (such as subsidence, e.g., Dyer et al 1999) as well as audit hydraulic fracture stimulation treatments (e.g., Maxwell and Urbancic 2005). Waveform attributes, such as amplitude and * E-mail: D.Angus@Leeds.ac.uk polarity, can be used to invert for the failure mechanisms (e.g., moment tensors) of both pre-existing and newly generated fractures or fracture systems (e.g., Baig and Urbancic 2010), as well as evaluate the fracture stimulation program (e.g., Baig et al 2011).…”

Defining Horizontal Well Objectives in Tight and Unconventional Gas Reservoirs

“…One final thought regarding the effects of permeability in unconventional gas reservoirs. The perception of what is required to make a productive shale completion is heavily biased by a picture of the successful Barnett shale completion that has developed over the last decade [12][13][14][15][16][17][18][19][20][21][22] . In this picture, complex multi-scale fracturing is seen as required to make a good well.…”

SCIMPI: A New Seafloor Observatory System

“…The seismic sensors distributed within and beneath the gas hydrate stability zone will also be used in repeated (4-D) active source seismic experiments to monitor changes in the distribution of gas hydrate and in the amount of free gas within the major conduit feeding the shallow gas hydrate deposit. Similar technology is used by industry to monitor the evolution of oil fields and hydrothermal energy sites [11,12,13,14,15,16,17,18].…”