Abstract: 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 comprising a fluid, and the broadband signal at least includes a portion of the sample data set at frequencies above 0.5 kHz.

Abstract: A method of identifying inflow locations along a wellbore includes obtaining an acoustic signal from a sensor within the wellbore, determining a plurality of frequency domain features from the acoustic signal, and identifying, using a plurality of fluid flow models, a presence of at least one of a gas phase inflow, an aqueous phase inflow, or a hydrocarbon liquid phase inflow at one or more fluid flow locations. The acoustic signal includes acoustic samples across a portion of a depth of the wellbore, and the plurality of frequency domain features are obtained across a plurality of depth intervals within the portion of the depth of the wellbore. Each fluid flow model of the plurality of fluid inflow models uses one or more frequency domain features of the plurality of the frequency domain features, and at least two of the plurality of fluid flow models are different.

Abstract: 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.

Abstract: A method of detecting a leak event within a wellbore can include inducing a pressure differential within a wellbore comprising a fluid, obtaining a sample data set representative of the acoustic signal across a frequency spectrum while inducing the pressure differential, determining a plurality of frequency domain features of the sample data set, determining a presence of a leak event at one or more depths within the wellbore based on determining that the plurality of frequency domain features match a leak event signature, correlating the leak event with the induced pressure differential, and determining a presence and location of a leak within the wellbore based on the presence of the leak event and the correlating of the leak event with the induced pressure differential.

Abstract: 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 comprising a fluid, and the broadband signal at least includes a portion of the sample data set at frequencies above 0.5 kHz.

Abstract: A method of detecting an event within a wellbore includes obtaining a sample data set, determining a plurality of frequency domain features of the sample data set, comparing the plurality of frequency domain features with an event signature, determining that the plurality of frequency domain features matches the thresholds, ranges, or both of the event signature, and determining the presence of the event within the wellbore based on determining that the plurality of frequency domain features match the thresholds, ranges, or both of the event signature. The sample data set is a sample of an acoustic signal originating within a wellbore including a fluid. The sample data set is representative of the acoustic signal across a frequency spectrum. The event signature includes a plurality of thresholds, ranges, or both corresponding to the plurality of frequency domain features.

Abstract: A method of detecting an event within a wellbore includes obtaining a sample data set, determining a plurality of frequency domain features of the sample data set, comparing the plurality of frequency domain features with an event signature, determining that the plurality of frequency domain features matches the thresholds, ranges, or both of the event signature, and determining the presence of the event within the wellbore based on determining that the plurality of frequency domain features match the thresholds, ranges, or both of the event signature. The sample data set is a sample of an acoustic signal originating within a wellbore including a fluid. The sample data set is representative of the acoustic signal across a frequency spectrum. The event signature includes a plurality of thresholds, ranges, or both corresponding to the plurality of frequency domain features.

Abstract: The invention comprises an inertial sensor comprising a frame, a proof mass, a first resonant element, the first resonant element being fixed to the frame and electrostatically coupled to the proof mass, and a second resonant element, the second resonant element being fixed to the frame, adjacent to the first resonant element such that there is substantially no electrostatic coupling between the second resonant element and the proof mass. A coupling is provided between the first resonant element and the second resonant element. A drive means is coupled to the first and second resonant elements for vibrating the first and second resonant elements and a sensor assembly is provided for detecting the amplitude of vibration of at least one of the resonant elements.

Abstract: An inertial sensor comprising: a frame; a proof mass suspended from the frame; a pair of first resonant elements electrically coupled to the proof mass, or to an intermediate component mechanically coupled to the proof mass, each first resonant element coupled to an opposite side of the proof mass to the other, the first resonant elements being substantially identical to one another and having substantially identical electrostatic coupling with the proof mass when the sensor is not accelerating; wherein the first resonant elements and proof mass lie substantially in a plane, and wherein movement of the proof mass relative to the first resonant elements orthogonal to the plane alters the electrostatic coupling between the proof mass and the first resonant elements; drive means coupled to the first resonant elements for vibrating each of the first resonant elements; and a sensor assembly for detecting a shift in the resonant frequency of each of the first resonant elements; and processing means for summing the

Abstract: The invention comprises an inertia! sensor comprising a frame, a proof mass; a first resonant element having a proximal end and a distal end, the first resonant element being fixed to the frame at its proximal end and coupled to the proof mass at its distal end, a second resonant element having a proximal end and a distal end, the second resonant element being fixed to the frame at its proximal end, adjacent to the first resonant element such that there is no coupling between the second resonant element and the proof mass, a means for coupling the first resonant element to the second resonant element; a drive means coupled to the first and second resonant elements for vibrating the first and second resonant elements; and a sensor assembly for detecting the amplitude of vibration of the resonant elements.

Abstract: An inertial sensor comprising: a frame; a proof mass suspended from the frame; a pair of first resonant elements electrically coupled to the proof mass, or to an intermediate component mechanically coupled to the proof mass, each first resonant element coupled to an opposite side of the proof mass to the other, the first resonant elements being substantially identical to one another and having substantially identical electrostatic coupling with the proof mass when the sensor is not accelerating; wherein the first resonant elements and proof mass lie substantially in a plane, and wherein movement of the proof mass relative to the first resonant elements orthogonal to the plane alters the electrostatic coupling between the proof mass and the first resonant elements; drive means coupled to the first resonant elements for vibrating each of the first resonant elements; and a sensor assembly for detecting a shift in the resonant frequency of each of the first resonant elements; and processing means for summing the

Abstract: The invention comprises an inertial sensor comprising a frame, a proof mass, a first resonant element, the first resonant element being fixed to the frame and electrostatically coupled to the proof mass, and a second resonant element, the second resonant element being fixed to the frame, adjacent to the first resonant element such that there is substantially no electrostatic coupling between the second resonant element and the proof mass. A coupling is provided between the first resonant element and the second resonant element. A drive means is coupled to the first and second resonant elements for vibrating the first and second resonant elements and a sensor assembly is provided for detecting the amplitude of vibration of at least one of the resonant elements.

Abstract: The invention comprises an inertia! sensor comprising a frame, a proof mass; a first resonant element having a proximal end and a distal end, the first resonant element being fixed to the frame at its proximal end and coupled to the proof mass at its distal end, a second resonant element having a proximal end and a distal end, the second resonant element being fixed to the frame at its proximal end, adjacent to the first resonant element such that there is no coupling between the second resonant element and the proof mass, a means for coupling the first resonant element to the second resonant element; a drive means coupled to the first and second resonant elements for vibrating the first and second resonant elements; and a sensor assembly for detecting the amplitude of vibration of the resonant elements.