A fiber optic distributed sensing system for installation within a wellbore is provided. The system includes a first set of downhole sensors having one or more nuclear sensors with nuclear field sensitivity. The system additionally includes, a second set of downhole sensors having one or more ElectroMagnetic (EM) sensors with electromagnetic field sensitivity. The fiber optic distributed sensing system also includes a processor system configured to receive data measurements from the first and second sets of sensors and configured to conjointly process the data measurements into representations of physical attributes of the wellbore.

Aspects of the subject technology relate to systems, methods, and computer-readable media for synthesizing sonic logs for downhole environments. Data associated with a wellbore in a formation is accessed. A model configured to identify one or more characteristics associated with sound traveling through one or more formation is accessed. The data is applied to the model to predict a characteristics of the formation that is identifiable through sonic logging.

A computer-implemented method for determining rock and fluid parameters of a subsurface region from measured seismic reflection data, said method including: generating, with a computer, a geophysical data volume by combining a plurality of angle stacks obtained from the measured seismic reflection data and geophysical property data obtained from a full wavefield inversion of the measured seismic reflection data; for each point of the geophysical data volume, determining, with a computer, a petrophysical model that is a probability of a rock state based on initial values of the rock and fluid parameters and the geophysical data volume; iteratively determining, using a computer, updated values for the rock and fluid parameters, wherein the iteratively determining includes determining a petrophysical parameter estimate for the rock and fluid parameters from the petrophysical model as constrained by the geophysical data volume and the initial values of the rock and fluid parameters, minimizing a misfit between the geophysical data volume and synthetic data generated from a forward modeling of the initial values of the rock and fluid parameters using a cost function that includes the petrophysical parameter estimate of the rock and fluid parameters, and repeating the iteratively determining until a predetermined stopping criteria is satisfied and final values for the rock and fluid parameters are generated, and each subsequent iteration of the iteratively determining replaces the initial values for the rock and fluid parameters with the updated values for the rock and fluid parameters from a previous iteration; determining, with a computer, uncertainty in the final values for the rock and fluid parameters; and exploring for or producing hydrocarbons using the final values for the rock and fluid parameters and there uncertainty.

A method includes acquiring measurement values from at least two different types of downhole tools disposed in a portion of a bore in a formation; selecting formation parameters for joint inversion; building a near-bore fluid flow model of at least a portion of the formation that includes at least the portion of the bore; simulating fluid flow based at least in part on the near-bore fluid flow model and the selected formation parameters to generate simulated measurement values; comparing the acquired measurement values and the simulated measurement values; based at least in part on the comparing, revising at least one of the selected formation parameters to generate revised formation parameters and simulating fluid flow based at least in part on the near-bore fluid flow model and the revised formation parameters to generate revised simulated measurement values; and outputting at least the revised formation parameters to characterize the formation.

Apparatus having a focused transducer and methods of operating a focused transducer downhole in a well can provide high resolution downhole imaging. In various embodiments, a focused transducer is used for imaging downhole in a well in which the imaging is based on a seismoelectric effect. In various embodiments, a focused transducer is used for imaging downhole in a well in which the imaging is based on an electroacoustic effect. Additional apparatus, systems, and methods are disclosed.

Methods and systems are disclosed. Methods may include obtaining well data along an interval of a well and identifying a first candidate interval within the interval using the well data. The well data includes acoustic data and porosity data. A formation surrounding the well within the first candidate interval includes micropores. The methods may further include determining mechanical parameter data along the first candidate interval based on the acoustic data and identifying a second candidate interval within the first candidate interval based on the mechanical parameter data and the porosity data. The methods may still further include determining water saturation data along the second candidate interval based on the well data, identifying a productive interval within the second candidate interval based on the water saturation data and a water saturation threshold, and determining a completion plan for the well based on the productive interval.

A method for adjusting a parameter of a wellbore operation includes: conveying a carrier through the wellbore; performing a resistivity measurement on the formation using a resistivity tool disposed on the carrier; performing an acoustic measurement on the formation using an acoustic tool disposed on the carrier; generating with a at least one processor a map of the formation using the resistivity measurement and the acoustic measurement, and adjusting the parameter using the map.

A Stoneley wave is generated in a borehole in a saturated porous earth formation. Measurements are made of the velocity of motion of the formation and the fluid in the formation. The difference in the velocities is indicative of formation permeability. An additional measurement of the electric field at the borehole wall enables determination of the electroacoustic constant.

The present disclosure describes methods and systems for downhole well integrity reconstruction in a hydrocarbon reservoir. One method for downhole well integrity reconstruction in a hydrocarbon reservoir includes: positioning, a laser head at a first subterranean location, wherein the laser head is attached to a tubular inside of a wellbore; directing, by the laser head, a laser beam towards a leak on the wellbore; and sealing the leak using the laser beam.