scholarly journals Fiber Optic Sensing for Geomechanical Monitoring: (2)- Distributed Strain Measurements at a Pumping Test and Geomechanical Modeling of Deformation of Reservoir Rocks

2019 ◽  
Vol 9 (3) ◽  
pp. 417 ◽  
Author(s):  
Xinglin Lei ◽  
Ziqiu Xue ◽  
Tsutomu Hashimoto
Keyword(s):  
Oil And Gas ◽  
Fiber Optic ◽  
Co2 Storage ◽  
Pumping Test ◽  
Numerical Approach ◽  
Rock Properties ◽  
Reservoir Rocks ◽  
Strain Data ◽  
Fiber Optic Sensing ◽  
Distributed Strain

In this study distributed fiber optic sensing has been used to measure strain along a vertical well of a depth of 300 m during a pumping test. The observed strain data has been used in geomechanical simulation, in which a combined analytical and numerical approach was applied in providing scaled-up formation properties. The outcomes of the field test have demonstrated the practical use of distributed fiber optic strain sensing for monitoring reservoir formation responses at different regions of sandstone–mudstone alternations along a continuous trajectory. It also demonstrated that sensitive and scaled rock properties, including the equivalent permeability and pore compressibility, can be well constrained by the combined use of water head and distributed strain data. In comparison with the conventional methods, fiber optic strain monitoring enables a lower number of short-term tests to be designed to calibrate the parameters used to model the rock properties. The obtained parameters can be directly used in long-term geomechanical simulation of deformation of reservoir rocks due to fluid injection or production at the CO2 storage and oil and gas fields.

Novel Near-Wellbore Fracture Diagnosis for Unconventional Wells Using High-Resolution Distributed Strain Sensing during Production

SPE Journal ◽  
2021 ◽  
pp. 1-10
Author(s):  
Ge Jin ◽  
Gustavo Ugueto ◽  
Magdalena Wojtaszek ◽  
Artur Guzik ◽  
Dana Jurick ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Fiber Optic ◽  
Fracture Network ◽  
Production Performance ◽  
Hydraulic Fractures ◽  
Fracture Aperture ◽  
Strain Sensing ◽  
Extensional Strain ◽  
Cluster Efficiency ◽  
Distributed Strain

Summary The characteristics of hydraulic fractures in the near-wellbore region contain critical information related to the production performance of unconventional wells. We demonstrate a novel application of a fiber-optic-based distributed strain sensing (DSS) technology to measure and characterize near-wellbore fractures and perforation cluster efficiency during production. Distributed fiber-optic-based strain measurements are made based on the frequency shift of the Rayleigh scatter spectrum, which is linearly dependent on strain and temperature changes of the sensing fiber. Strain changes along the wellbore are continuously measured during the shut-in and reopening operations of a well. After removing temperature effects, extensional strain changes can be observed at locations around the perforation cluster during a shut-in period. We interpret that the observed strain changes are caused by near-wellbore fracture aperture changes caused by pressure increases within the near-wellbore fracture network. The depth locations of the measured strain changes correlate well with distributed acoustic sensing (DAS) acoustic intensity measurements that were measured during the stimulation of the well. The shape and magnitude of the strain changes differ significantly between two completion designs in the same well. Different dependencies between strain and borehole pressure can be observed at most of the perforation clusters between the shut-in and reopening periods. We assess that this new type of distributed fiber-optic measurement method can significantly improve understanding of near-wellbore hydraulic fracture characteristics and the relationships between stimulation and production from unconventional oil and gas wells.

scholarly journals A Review of Distributed Fiber--optic Sensing in the Oil and Gas Industry

2021 ◽  
pp. 1-1
Author(s):  
Islam Ashry ◽  
Yuan Mao ◽  
Biwei Wang ◽  
Frode Hveding ◽  
Ahmed Bukhamseen ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Fiber Optic ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Fiber Optic Sensing

scholarly journals In situ hydromechanical responses during well drilling recorded by fiber-optic distributed strain sensing

Solid Earth ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 2487-2497
Author(s):  
Yi Zhang ◽  
Xinglin Lei ◽  
Tsutomu Hashimoto ◽  
Ziqiu Xue
Keyword(s):  
Fiber Optic ◽  
Drilling Fluid ◽  
Flow Behavior ◽  
Co2 Storage ◽  
Fluid Pressure ◽  
Well Testing ◽  
Strain Sensing ◽  
Well Drilling ◽  
Distributed Strain

Abstract. Drilling fluid infiltration during well drilling may induce pore pressure and strain perturbations in neighbored reservoir formations. In this study, we report that such small strain changes (∼20 µε) have been in situ monitored using fiber-optic distributed strain sensing (DSS) in two observation wells with different distances (approximately 3 and 9 m) from the new drilled wellbore in a shallow water aquifer. The results show the layered pattern of the drilling-induced hydromechanical deformation. The pattern could be indicative of (1) fluid pressure diffusion through each zone with distinct permeabilities or (2) the heterogeneous formation damage caused by the mud filter cakes during the drilling. A coupled hydromechanical model is used to interpret the two possibilities. The DSS method could be deployed in similar applications such as geophysical well testing with fluid injection (or extraction) and in studying reservoir fluid flow behavior with hydromechanical responses. The DSS method would be useful for understanding reservoir pressure communication, determining the zones for fluid productions or injection (e.g., for CO2 storage), and optimizing reservoir management and utilization.

Estimation of Undisturbed Geothermal Gradient in Wells From Measured Drilling Data: A Numerical Approach

2017 ◽  
Author(s):  
Lucas Cantinelli Sevillano ◽  
Jesus De Andrade ◽  
Sigbjørn Sangesland
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Temperature Distribution ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Geothermal Gradient ◽  
Computer Code ◽  
Numerical Approach ◽  
Rock Properties ◽  
Drilling Fluids

The undisturbed geothermal gradient is a key thermal boundary that drives heat transfer processes occurring in oil and gas wells throughout their lifetime. However, the temperature distribution with depth is somewhat uncertain, and this is often assumed to be a linear approximation from the mudline to the bottom of the well. During drilling, the circulating temperature may significantly affect the rheology of the drilling fluids and the cement setting processes. Therefore, erroneous estimates of the wellbore temperature may affect the overall performance of the drilling phase and subsequent well operations. Further, it is important to know the accurate temperature distribution within the formation for assessment of the petroleum prospectivity through source rock maturation and reservoir quality. This paper presents a numerical methodology to estimate the undisturbed geothermal gradient while drilling in offshore wells. This methodology may also be applied to onshore wells by simplification. The new approach is based on an in-house axisymmetric wellbore transient thermal model, in which the equations are solved using the finite difference method. The model computes the heat transfer between the well and riser system with the surroundings. However, other computational codes may also be used following the framework presented in this study. The computer code should provide a detailed representation of the geometry of the wellbore, the physical properties of the drilling fluid and formation, the suitable thermal boundary conditions and temporal discretization. The temperatures of the fluid at the inlet of the drillstring and at the bottom hole assembly (BHA), in the annulus A, are used as input to the numerical model that iteratively adjusts the undisturbed geothermal gradient, which generated the temperature recordings while drilling. The paper comprises cases studies of hypothetical wells drilled in relevant offshore areas in the world, each with their distinctive and variable geothermal gradient, defined by the different rock formations encountered. Uncertainties regarding the thermal properties of the rock were also considered to ascertain the robustness of the code. The water depth of the drilling site was also observed to impact the convergence of the algorithm. The results obtained by the numerical approach are in good agreement with the expected values of the undisturbed formation temperatures. The novelty of the numerical framework is the ability to provide reliable and satisfactory estimates of the undisturbed geothermal gradient for wellbores with any configuration, lithology and rock properties. These estimates are based on temperature measurements of the circulating drilling fluid at the BHA and account for uncertainty in rock thermal properties; in reasonable time using standard engineering computers.

A Fully Distributed Strain Rosette Using High Definition Fiber Optic Sensing

2019 ◽  
Author(s):  
Elias Bearinger ◽  
Dan Kominsky ◽  
Reginald Bryson ◽  
Nur Aida Abdul Rahim
Keyword(s):  
Fiber Optic ◽  
High Definition ◽  
Strain Rosette ◽  
Fiber Optic Sensing ◽  
Distributed Strain

scholarly journals Distributed Fiber Optic Strain Sensing for Geomechanical Monitoring: Insights from Field Measurements of Ground Surface Deformation

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 285
Author(s):  
Rasha Amer ◽  
Ziqiu Xue ◽  
Tsutomu Hashimoto ◽  
Takeya Nagata
Keyword(s):  
Oil And Gas ◽  
Fiber Optic ◽  
Surface Deformation ◽  
Co2 Storage ◽  
Ground Surface ◽  
Field Tests ◽  
Deformation Monitoring ◽  
Water Tank ◽  
Strain Sensing ◽  
Geomechanical Monitoring

In recent years, distributed fiber optic strain sensing (DFOSS) technology has demonstrated a solution for continuous deformation monitoring from subsurface to surface along the wellbore. In this study, we installed a single-mode optical fiber cable in a shallow trench to establish an effective technique for ground surface deformation mapping. We conducted three experimental field tests (iron plate load, water tank filling up load, and airbag inflation) in order to confirm the strain sensitivity of DFOSS for static loads, dynamic overload, excavation, subsidence, and uplift. This paper also presents two installation methods to couple the fiber cable with the ground under various environmental conditions; here, the fiber cable was installed in a shallow trench with one part buried in the soil and another part covered with cement. Our results suggest that covering the cable with cement is a practical approach for installing a fiber cable for ground surface deformation monitoring. By combining this approach with wellbore DFOSS, accurate surface–subsurface deformation measurements can be obtained for three-dimensional geomechanical monitoring of CO2 storage and oil and gas fields in the future.

scholarly journals New Understanding of Bar Top Hollows in Dryland Sandy Braided Rivers from Outcrops with Unmanned Aerial Vehicle and Ground Penetrating Radar Surveys

2021 ◽  
Vol 13 (4) ◽  
pp. 560
Author(s):  
Xianguo Zhang ◽  
Chengyan Lin ◽  
Tao Zhang ◽  
Daowu Huang ◽  
Derong Huang ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Ground Penetrating Radar ◽  
Oil And Gas ◽  
Co2 Storage ◽  
Middle Part ◽  
Basal Surface ◽  
Depositional Sequence ◽  
Braided Rivers ◽  
Aerial Vehicle ◽  
Ground Penetrating

Bar top hollows (BTHs) are morphological elements recognized in modern braided rivers; however, information regarding their depositional features and types of filling units in ancient strata is unclear. This is an important reason behind why it is difficult to identify BTH units in subsurface reservoirs. A Middle Jurassic dryland sandy braided river outcrop in northwestern China is characterized in this study through the application of an unmanned aerial vehicle (UAV) surveying and mapping, and ground penetrating radar (GPR). A workflow of UAV data processing has been established, and a 3D digital outcrop model has been built. By observation and measurement of the outcrop model and GPR profiles, two types of BTH filled units were found: (a) sandstone-filled, and (b) mudstone-filled hollows. Both of these units were located between two adjacent bar units in an area that is limited to a compound bar, and were developed in the upper part of a braided bar depositional sequence. The ellipse-shaped, sandstone-filled unit measures 10 m × 27 m in map view and reaches a maximum thickness of 5 m. The transversal cross-section across the BTHs displays a concave upward basal surface, while the angle of the inclined structures infilling the BTHs decreases up-section. The GPR data show that, in the longitudinal profile, the basal surface is relatively flat, and low-angle, inclined layers can be observed in the lower- and middle part of the sandstone-filled BTHs. In contrast, no obvious depositional structures were observed in the mudstone-filled BTH in outcrop. The new understanding of BTH has a wide application, including the optimization of CO2 storage sites, fresh water aquifers exploration, and oil and gas reservoir characterization.

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