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.

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 method of identifying events includes obtaining an acoustic signal from a sensor, determining one or more frequency domain features from the acoustic signal, providing the one or more frequency domain features as inputs to a plurality of event detection models, and determining the presence of one or more events using the plurality of event detection models. The one or more frequency domain features are obtained across a frequency range of the acoustic signal, and at least two of the plurality of event detection models are different.

A method of identifying events includes obtaining an acoustic signal from a sensor, determining one or more frequency domain features from the acoustic signal, providing the one or more frequency domain features as inputs to a plurality of event detection models, and determining the presence of one or more events using the plurality of event detection models. The one or more frequency domain features are obtained across a frequency range of the acoustic signal, and at least two of the plurality of event detection models are different.

Fluid characteristics of a well fluid can be monitored. For example, a computing device can receive sensor signals from an acoustic sensor positioned on a well tool. The sensor signals can indicate characteristics of acoustic emissions generated by a well fluid impacting the well tool. The computing device can determine an acoustic signature for the well fluid using the characteristics of the acoustic emissions. The computing device can determine a difference between the acoustic signature a baseline acoustic-signature for the well fluid. The computing device can determine one or more fluid characteristics of the well fluid using the difference between the acoustic signature and the baseline acoustic-signature. The computing device can transmit a notification indicating the one or more fluid characteristics.

A method of detecting sand inflow into a wellbore is disclosed. The method can include obtaining a sample data set, detecting a broadband signal within the sample data set, comparing the broadband signal with a signal reference, determining that the broadband signal meets or exceeds the signal reference, and determining the presence of sand inflow into the wellbore based on determining that the broadband signal meets or exceeds the signal reference. The sample data set can be a sample of an acoustic signal originating within a wellbore including a fluid, and the broadband signal at least includes a portion of the sample data set at frequencies above 0.5 kHz.

A method of detecting sand inflow into a wellbore is disclosed. The method can include obtaining a sample data set, detecting a broadband signal within the sample data set, comparing the broadband signal with a signal reference, determining that the broadband signal meets or exceeds the signal reference, and determining the presence of sand inflow into the wellbore based on determining that the broadband signal meets or exceeds the signal reference. The sample data set can be a sample of an acoustic signal originating within a wellbore including a fluid, and the broadband signal at least includes a portion of the sample data set at frequencies above 0.5 kHz.

In the general context of oilfield equipment and, in particular, in the context of downhole tools, the systems and methods relate to characterizing flow in a wellbore using data collection devices, which may be temporarily attached on the outside of a work string to be run into the wellbore. More particularly, the systems and methods may be used for obtaining flow data at a plurality of different locations and correlated with wellbore depth for evaluation of production profiles of wellbores. A system may be provided that comprises a work string, multiple external support devices temporarily secured to an exterior of the work string at a plurality of different locations, and at least one data collection device such as a resistivity gauge, flow meter, and/or Doppler sensor, coupled to the external support devices. This data, once recovered on surface, could be incorporated into an overall production profile model of the well.

In the general context of oilfield equipment and, in particular, in the context of downhole tools, the systems and methods relate to characterizing flow in a wellbore using data collection devices, which may be temporarily attached on the outside of a work string to be run into the wellbore. More particularly, the systems and methods may be used for obtaining flow data at a plurality of different locations and correlated with wellbore depth for evaluation of production profiles of wellbores. A system may be provided that comprises a work string, multiple external support devices temporarily secured to an exterior of the work string at a plurality of different locations, and at least one data collection device such as a resistivity gauge, flow meter, and/or Doppler sensor, coupled to the external support devices. This data, once recovered on surface, could be incorporated into an overall production profile model of the well.