We modeled cross-well strain/strain rate responses of fiber optic sensing, including distributed strain sensing (DSS) and low-frequency acoustic (DAS), to hydraulic stimulation. DSS DAS have been used measure or the characterize fractures. However, current application DSS/DAS is limited acquisition, processing, qualitative interpretations. The lack geomechanical models hinders development technology toward quantitative interpretation inversion. developed a strategy use displacement...

ABSTRACT Distributed acoustic sensing uses an optical fibre together with interrogator unit to perform strain measurements. The usage of distributed in geophysics is attractive due its dense spatial sampling and low operation cost if the freely accessible. In borehole environment, fibres for are often readily available as a part other tools, such temperature pressure. Although system promises great potential reservoir monitoring surface seismic acquisition, single axial measurement along...

Distributed acoustic sensing (DAS) data are increasingly used in geophysics. Lower cost and higher spatial resolution, DAS appealing, especially boreholes which optical fibers readily available. has the potential to become a permanent reservoir monitoring tool with reduced time interval. To accomplish this goal, it is critical that can record all wave modes fully characterize properties. This goal be achieved by recording complete strain tensor consisting of 6C. Conventional provides...

Summary Recently more distributed acoustic sensing (DAS) data have been collected during hydraulic fracturing in shale. Low-frequency DAS signals show patterns that are intuitively consistent with the understanding of strain field around fractures. This study uses a fracture simulator combined finite element solver to further understand various caused by fracturing. The results can serve as “type-curve” template for interpretation cross-well plots. Incorporating detailed pump schedule and...

Distributed Acoustic Sensing (DAS) data in boreholes are not commonly used for reservoir characterization because multicomponent needed to quantify different wave modes. We propose two approaches obtain DAS by using either multiple parallel optical fibers or a helical fiber. The use the shape sensing method which is based on measurements of axial strain gradient curvature cable and then reconstruct components displacement field. However, simply does provide sufficient information...

Abstract Faults play an important role in recharging many geothermal reservoirs, and seismic information can image the locations of these faults. The value (VOI) metric is used to objectively quantify compare two types receiver data via a machine learning approach. demonstrated VOI methodology novel by including spatial models from obtaining statistics learning. Our two-dimensional numerical experiments images created sparsely spaced (80 m), two-component geophone sampling high resolution (1...

Summary The objective of this study is to understand how microseismic events are generated during hydraulic fracturing, as well the role geomechanical conditions (i.e., stress and mechanical stratigraphy) in process. In industry, event clouds have been generally used an “outer boundary” “stimulated reservoir volume” (SRV). However, by comparing with other surveillance data (low-frequency distributed acoustic sensing, or LF-DAS, strain) Hydraulic Fracturing Test Site (HFTS) 2 experiment, we...

The usage of Distributed Acoustic Sensing (DAS) in geophysics is attractive due to its dense spatial sampling and low operation cost if the optical fiber easily accessible. In borehole environment, fibers for DAS are often readily available as a part other sensing tools, such temperature pressure. Although system promises unlimited potential reservoir monitoring surface seismic acquisition, single axial strain measurement along inadequate fully characterize different wave modes, thus making...

The usage of Distributed Acoustic Sensing (DAS) in geophysics is rapidly gaining popularity due to its dense spatial sampling and low operation cost, given that the optical fiber easily accessible. In borehole environment, fibers for DAS are often readily available as a part other sensing tools, such temperature pressure. Although provides single axial strain measurement along fiber, entire tensor can also be recovered through combination purposefully-designed fibers. Such reconstruction...

Abstract Recently new Distributed Acoustic Sensing (DAS) data have been collected during hydraulic fracturing in shale. Low frequency DAS signals show patterns that are intuitively consistent with the understanding of strain field around fractures. This study utilizes a fracture simulator combined finite element solver to further understand various caused by fracturing. The results can serve as "type-curve" template for interpretation cross well plots. Incorporating detailed pump schedule...

Reverse time migration (RTM) is commonly regarded as a memory intensive operation because of the need to access source and receiver wavefields synchronously, which in principle require large amount storage. Many methods are proposed manipulate wavefield efficiently, such storing several layers around computational domain for reconstruction. By using integral solution representation theorem, we can reduce boundary storage single layer without compromising accuracy. We propose reconstruction...

Distributed acoustic sensing (DAS) acquisition in borehole environments has seen rapid growth recently. However, the majority of DAS imaging applications convert native strain observations to equivalent displacement or velocity measurements order be compatible with conventional seismic data processing. In contrast, we formulate elastic least-square reverse time migration (ELSRTM) energy norm condition for data. ELSRTM provides an accurate representation subsurface through reduction artifacts...

Hydraulic fracturing induces a network of fractures to promote the flow oil and gas in tight shale reservoirs. In this paper, we discuss detection fracture hits during stimulation avoid reaching an observing well. Our aim is devise early warning system for cases where interference may adversely affect production. We propose use image-based algorithms such as template matching convolutional neural (CNN) on lowfrequency signals distributed acoustic sensing (DAS) data detect precursor events...

Summary As the need for continuous passive seismic monitoring grows, we continue to seek sensors that can provide a large aperture and are highly repeatable. Distributed acoustic sensing provides unique opportunity deploy optical fibres as complementary distributed instrument is repeatable once permanently deployed (i.e., trenched or cemented) with minimal maintenance effort when installed correctly. Additional cost savings be achieved repurposing existing network of telecommunication...

Nondestructive testing (NDT) is critical in probing a wellbore's condition without causing additional structure disruption. Timely on-demand NDT crucial to detect and evaluate defects, allowing prompt intervention maintenance. We propose novel method that has low HSE footprint, execution cost, high repeatability. It utilizes pre-existing yet innovative acoustic source, i.e., resonance speaker, strapped on the wellhead generate seismic tube waves along disposable fiber optic instrumented well...

Accurate seismic event locations are necessary for understanding induced seismicity. The first step in location processing is picking the arrival times of P and S waves recorded on all available sensors. A machine learning workflow can ingest raw passive data from multiple sensors to identify wave arrivals. Despite using algorithms picking, considerable human oversight required ensure detection fidelity. This paper proposes a consisting physics-informed methods achieve total automation...

Faults play an important role in recharging many geothermal reservoirs, and seismic information can image the locations of these faults. Sensors such as DAS have potential to both higher temporal spatial resolution than geophones. The value (VOI) metric is used toobjectively quantify single-component horizontal DAS, compared more sparsely-spaced geophones, using receivers together. This methodology quantifies accuracy fault migration images when fibers, geophones a combination two are...