Systems and methods are provided for geosteering in directional drilling based on water detection. An exemplary method includes determining a signal-to-noise ratio (SNR) for an electromagnetic communication between devices on a bottom hole assembly, and determining a distance to water based, at least in part, on the SNR. Adjustments to geosteering vectors for the bottom hole assembly are determined based, at least in part, on the distance to water.

The invention provides a three-dimensional resistivity probe for in-situ monitoring comprises: a probe rod body inside which one or more subordinate controllers are provided; a control cabin inside which a main controller is provided disposed at the top of the probe rod body; and a cone tip provided at the bottom of the probe rod body; wherein the probe rod body comprising: a plurality of resistivity sensor modules, wherein each resistivity sensor module including a plurality of insulating rings, each insulating ring having a protruded part at a top end and a groove fitting into at a bottom end, three or more point-electrode grooves are formed at the top end of each insulating ring and two through holes allowing two positioning rods to insert into for assembly are opened thereon and the outer end of each point-electrode groove extends to an outer circumference of each insulating ring. The invention could establish a three-dimensional resistivity dynamic monitoring system, through the three-dimensional resistivity dynamic monitoring system, the transport law and mechanism of water and salt transport, caused by different disaster chain origins, in a special soil body can be revealed, and the water and salt transport spatial distribution dynamic change process in a coastal zone is subjected to high spatial resolution and high precision in-situ long-term monitoring.

A method for completing a wellbore traversing a subterranean formation includes making electromagnetic resistivity measurements along a lateral section of the wellbore. The resistivity measurements are evaluated to estimate a water content of the subterranean formation along the lateral section. The formation is fractured at selected regions along the lateral section at which the water content is below a threshold and avoiding regions at which the water content is above the threshold.

Offshore electromagnetic (EM) reservoir monitoring systems and methods, including a system with a light source producing a light beam and an EM sensor array deployed at the bottom of a body of water and above one or more subsea regions of interest, the array coupled to the light source with an optical fiber. An EM sensor modulates the interrogation light beam in response to an EM signal induced into the subsea formation by an EM source. The system further includes a processor controlling the light source, processing modulated light received from the array, and collecting data with the array to produce EM surveys, each EM survey based on data sets collected at different times. The EM sensor is physically isolated from a surrounding subsea environment. The surveys are combined to produce a time lapse earth model of the regions of interest.

Methods and systems are provided for characterizing formation water salinity of subsurface formation using multifrequency permittivity data over a range of frequencies below 1 MHz. The multifrequency permittivity data is processed to determine salinity of formation water contained in the subsurface formation. Other useful formation properties (such as formation water saturation) can be determined based on the formation water salinity.

A subaqueous underground survey system using a reflection seismic survey method includes: multiple sound sources 1 for generating sound waves in the water; a controller 2 for controlling phases of the sound waves; a geophone 3 for receiving reflected waves of the sound waves; and an observation ship 4 equipped with the sound sources 1, wherein the controller 2 controls phases of the sound sources 1 so that the sound waves generated from the respective sound sources 1 have a phase difference at a water bottom surface B, thereby controlling generation of shear waves to propagate into the ground.

Acoustic Doppler current Profile (ADP) data may be collected by floating vessels down a section of a river. The ADP data may be merged with LIDAR data or other image data. The data may be processed to determine river attributes, such as flow velocity for a specific river level (flow volume). River attributes may also include depth, water clarity, temperature, and/or other river attributes. Capture of ADP data at different river levels may be interpolated between measures to estimate river attributes at multiple river levels that are different from the river levels associated with the collected ADP data. The processed data may be used to assess drift of particles/objects through a section of the river and/or identify conforming habitat in the section of the river based at least in part on parameters of the habitat, among other possible uses of the processed data.

A nuclear magnetic resonance (NMR) measurement, at two or more depths of investigation, of a subsurface formation containing formation water and a mud filtrate from a water-base mud is obtained, and the mud filtrate is distinguished from the formation water. A NMR logging tool is disposed in a wellbore penetrating the formation containing the mud filtrate and the formation water and NMR measurements at different radial depths of investigation into the formation are made. The mud filtrate is distinguished from the formation water by determining the relative salinities of the mud filtrate and the formation water. The relative salinities are determined by comparing distribution relaxation times across different depths of investigation or by comparing logarithmic mean values across different depths of investigation.

A borehole while-drilling electromagnetic tomography advanced detection apparatus includes a site host, a drilling rig, a detecting pipe screwed coupling on one end to a drilling stem of the drilling rig, a drilling bit screwed coupling to the other end of the detecting pipe, wherein the detecting pipe is provided with a probe comprising a transmitting coil, a receiving coil, an electromagnetic transmitting module, an electromagnetic receiving module, a SCM (Single Chip Microcomputer), a 3D electronic compass, a network interface of the probe and a first memory, in which the memory port of the SCM is connected to the first memory, and the network interface of the probe can be data-communicated with the site host.

Concurrently measuring, correlating, and processing magnetic and electric field data includes measuring base band signals, and then up-converting those band signals to a higher frequency for filtering, while at the same time preserving phase and amplitude information. All timed elements in the system are rigorously synchronized. The increased data set results in improved signal-to-noise ratio and information correlation.