Monitoring and diagnosing completion during hydraulic fracturing operations provides insights into the fracture geometry, inter-well frac hits and connectivity. Conventional monitoring methods (microseismic, borehole gauges, tracers, etc.) can provide a range of information about the stimulated rock volume but may often be limited in detail or clouded by uncertainty. Utilization of DAS as a fracture monitoring tool is growing, however most of the applications have been limited to acoustic frequency bands of the DAS recorded signal. In this paper, we demonstrate some examples of using the low-frequency band of Distributed Acoustic Sensing (DAS) signal to constrain hydraulic fracture geometry. DAS data were acquired in both offset horizontal and vertical monitor wells. In horizontal wells, DAS data records formation strain perturbation due to fracture propagation. Events like fracture opening and closing, stress shadow creation and relaxation, ball seat and plug isolation can be clearly identified. In vertical wells, DAS response agrees well with co-located pressure and temperature gauges, and illuminates the vertical extent of hydraulic fractures. DAS data in the low-frequency band is a powerful attribute to monitor small strain and temperature perturbation in or near the monitor wells. With different fibered monitor well design, the far-field fracture length, height, width, and density can be accurately measured using cross-well DAS observations.

A method and system can obtain real time property measurements of a fluid comprising a formation fluid downhole, real time measurements of an amount of an interactive component of the fluid downhole, and real time measurements of an amount of a non-interactive component of the fluid downhole. The method and system further includes determining a total amount of the interactive component in the fluid or a contamination level of the formation fluid at a time of interest based on the real time property measurements of the fluid downhole and the real time measurements of the amounts of the interactive component and non-interactive component downhole. The real time measurements of the amount of the interactive component downhole are real time measurements of the amount of the interactive component in its free form downhole, and the property can be scaled with the contamination level.

An x-ray-based borehole fluid evaluation tool for evaluating the characteristics of a fluid located external to said tool in a borehole using x-ray backscatter imaging is disclosed, the tool including at least an x-ray source; a radiation shield to define the output faun of the produced x-rays into the borehole fluid outside of the tool housing; at least one collimated imaging detector to record x-ray backscatter images; sonde-dependent electronics; and a plurality of tool logic electronics and power supply units. A method of using an x-ray-based borehole fluid evaluation tool to evaluate the characteristics of a fluid through x-ray backscatter imaging is also disclosed, the method including at least producing x-rays in a shaped output; measuring the intensity of backscatter x-rays returning from the fluid to each pixel of one or more array imaging detectors; and converting intensity data from said pixels into characteristics of the wellbore fluids.

An x-ray-based borehole fluid evaluation tool for evaluating the characteristics of a fluid located external to said tool in a borehole using x-ray backscatter imaging is disclosed, the tool including at least an x-ray source; a radiation shield to define the output faun of the produced x-rays into the borehole fluid outside of the tool housing; at least one collimated imaging detector to record x-ray backscatter images; sonde-dependent electronics; and a plurality of tool logic electronics and power supply units. A method of using an x-ray-based borehole fluid evaluation tool to evaluate the characteristics of a fluid through x-ray backscatter imaging is also disclosed, the method including at least producing x-rays in a shaped output; measuring the intensity of backscatter x-rays returning from the fluid to each pixel of one or more array imaging detectors; and converting intensity data from said pixels into characteristics of the wellbore fluids.

Systems and methods for measuring flow velocity of a fluid mixture in a lateral section of an oil/gas well are presented. The flow velocity is measured by tracking movement of particles and/or features in the fluid mixture via visible and/or infrared imaging sensors of a camera-based flow sensor. According to another aspect, the imaging sensors detect back-reflected light by the particles and/or features, the light emitted by illuminators in the visible and/or infrared spectrum. According to yet another aspect, the particles are quantum dot illuminators injected into the fluid mixture, the flow velocity based on a time-of-flight of the quantum dots. The camera-based flow sensor may be rotatable to measure flow velocities at different angular positions of a pipe, rotation provided by rotation of an element of a mobile vessel to which the flow sensor is rigidly coupled.

This invention relates to the method of assessing the integrity of primary and secondary barriers in the interval where a cement plug is to be installed in the well proposed for abandonment. The technical result of the invention is to enhance the accuracy of wellbore barrier integrity assessment. The method of well integrity assessment below production packer, including inner and outer casings, tubing string and production packer installed inside the casing, and cement sheath and adjacent rocks, comprising the following phases: Identification of the target zone for cement plug installation; installation of a temporary cement plug below the target zone; pressure testing and assessment of tubing and below-packer zone integrity based on steady pressure data or pressure variation in time; creation of a perforation zone in casing and cement below production packer in the target zone; conducting a logging survey including noise, temperature, defectoscopy, and production logging in the target zone during a repeat pressure test; issuance of a findings report on casing and cement integrity and subsequent installation of a cement plug for well abandonment, including rigless operations or remedial cementing at designated locations where integrity failures have been identified on the basis of logging data.

This invention relates to the method of assessing the integrity of primary and secondary barriers in the interval where a cement plug is to be installed in the well proposed for abandonment. The technical result of the invention is to enhance the accuracy of wellbore barrier integrity assessment. The method of well integrity assessment below production packer, including inner and outer casings, tubing string and production packer installed inside the casing, and cement sheath and adjacent rocks, comprising the following phases: Identification of the target zone for cement plug installation; installation of a temporary cement plug below the target zone; pressure testing and assessment of tubing and below-packer zone integrity based on steady pressure data or pressure variation in time; creation of a perforation zone in casing and cement below production packer in the target zone; conducting a logging survey including noise, temperature, defectoscopy, and production logging in the target zone during a repeat pressure test; issuance of a findings report on casing and cement integrity and subsequent installation of a cement plug for well abandonment, including rigless operations or remedial cementing at designated locations where integrity failures have been identified on the basis of logging data.

Methods and apparatus for hydrocarbon monitoring are provided. A method that may be performed by a flowmeter or monitoring system includes receiving downhole measurements of a flowing fluid from a flowmeter; determining a standard phase fraction of the flowing fluid based on the downhole measurements from the flowmeter; receiving surface measurements of the flowing fluid; determining a surface phase fraction of the flowing fluid based on the surface measurements; comparing the standard phase fraction to the surface phase fraction; based on the comparison being greater than a predetermined threshold, using the surface measurements as a reference to adjust a speed of sound (SoS) of a first phase until a target value is achieved; and receiving additional downhole measurements of the flowing fluid from the flowmeter, wherein the flowmeter is operating using the adjusted SoS of the first phase.

A system for downhole measurements. The system may comprise a fiber optic cable that further comprises a transmission fiber and a return fiber. Additionally, the system may comprise a passive optical device optically connected to the transmission fiber and the return fiber, a first wavelength division multiplexer (WDM) optically connected to the transmission fiber, and a second WDM optically connected to the return fiber. The system may further comprise a transmitter and a first Raman pump optically connected to the first WDM and a receiver and a second Raman pump optically connected to the second WDM.

Aspects of the subject technology relate to systems and methods for optimizing production flow monitoring by utilizing data driven in-situ injection. Systems and methods are provided for receiving sensor data from at least one of a distributed fiber optic sensing line positioned along a wellbore and a plurality of subsurface and surface sensors, generating flow models based on the sensor data received from the at least one of the distributed fiber optic sensing line and the plurality of subsurface and surface sensors to optimize production flow, and generating flow profiles based on the flow models and the sensor data received from the at least one of the distributed fiber optic sensing line and the plurality of subsurface and surface sensors to adjust zonal inflow device.