A method includes collecting a first set of borehole gravity data at a first time step along a length of a first wellbore and collecting a second set of borehole gravity data at the first time step along a length of a second wellbore. The method also includes interpolating a third set of borehole gravity data at the first time step in an area between the first wellbore and the second wellbore using the first and the second sets of borehole gravity data. Further, the method includes determining a first fluid saturation and a fluid saturation change over time in a reservoir containing the first wellbore and the second wellbore using the first set, the second set, and the third set. Moreover, the method includes controlling wellbore production operations or wellbore injection operations at the first wellbore based on the fluid saturation change.

A post-compensation method for motion errors of a rotating accelerometer gravity gradiometer includes the steps of: during moving-base gravity gradient exploration, recording angular and linear motions of a gravity gradiometer; after the exploration, removing angular and linear motion errors from output data of the gravity gradiometer based on an analytical model of the rotating accelerometer gravity gradiometer; while ensuring that the precision of the gravity gradiometer is unchanged, the post-compensation method for the motion errors may be applied to greatly reduce the requirements of the gravity gradiometer for the precision of an online error compensation system, thereby simplifying the circuit design and mechanical design of the rotary accelerometer gravity gradiometer, and making the rotating accelerometer gravity gradiometer simpler and cheaper.

A post-compensation method for motion errors of a rotating accelerometer gravity gradiometer includes the steps of: during moving-base gravity gradient exploration, recording angular and linear motions of a gravity gradiometer; after the exploration, removing angular and linear motion errors from output data of the gravity gradiometer based on an analytical model of the rotating accelerometer gravity gradiometer; while ensuring that the precision of the gravity gradiometer is unchanged, the post-compensation method for the motion errors may be applied to greatly reduce the requirements of the gravity gradiometer for the precision of an online error compensation system, thereby simplifying the circuit design and mechanical design of the rotary accelerometer gravity gradiometer, and making the rotating accelerometer gravity gradiometer simpler and cheaper.

A method and a system implementing the method, are disclosed for computing magnetic interferences in measurement while drilling operations, using the retrieved lateral, and axial magnetic interferences of the measurement while drilling downhole tool system. With the disclosed method and system of implementing the method, it can be determined whether the source of the magnetic interference is from the measurement while drilling downhole tool system lateral direction or its axial direction. When magnetic field strength is abnormal, the lateral and axial magnetic interferences are monitored, and then compared against their values before the abnormal magnetic field strength. This way the direction of the magnetic interference is analyzed to eliminate or judge the cause of the interference, and properly guide the measurement while drilling downhole tool system towards its reservoir or well location.

A method and a system implementing the method, are disclosed for computing magnetic interferences in measurement while drilling operations, using the retrieved lateral, and axial magnetic interferences of the measurement while drilling downhole tool system. With the disclosed method and system of implementing the method, it can be determined whether the source of the magnetic interference is from the measurement while drilling downhole tool system lateral direction or its axial direction. When magnetic field strength is abnormal, the lateral and axial magnetic interferences are monitored, and then compared against their values before the abnormal magnetic field strength. This way the direction of the magnetic interference is analyzed to eliminate or judge the cause of the interference, and properly guide the measurement while drilling downhole tool system towards its reservoir or well location.

The present invention discloses a method for determining an inverse of gravity correlation time. During data processing on gravity measurement of moving bases, a gravity anomaly is considered as a stationary random process in a time domain, and is described with a second-order Gauss Markov model, a third-order Gauss Markov model or an m.sup.th-order Gauss Markov model, and the inverse of gravity correlation time is an important parameter of the gravity-anomaly model, and according to a gravity sensor root mean square error, a Global Navigation Satellite System (GNSS) height root mean square error, an a priori gravity root mean square, and a gravity filter cutoff frequency during the gravity measurement of the moving bases, an inverse of gravity correlation time of the second-order, third-order or m.sup.th-order Gauss Markov model is determined. According to the method for determining an inverse of gravity correlation time provided in the present invention, a forward and backward Kalman filter during data processing on gravity measurement of moving bases can be adjusted, to obtain a high-precision and high-wavelength-resolution gravity anomaly value.

The present invention discloses a method for determining an inverse of gravity correlation time. During data processing on gravity measurement of moving bases, a gravity anomaly is considered as a stationary random process in a time domain, and is described with a second-order Gauss Markov model, a third-order Gauss Markov model or an m.sup.th-order Gauss Markov model, and the inverse of gravity correlation time is an important parameter of the gravity-anomaly model, and according to a gravity sensor root mean square error, a Global Navigation Satellite System (GNSS) height root mean square error, an a priori gravity root mean square, and a gravity filter cutoff frequency during the gravity measurement of the moving bases, an inverse of gravity correlation time of the second-order, third-order or m.sup.th-order Gauss Markov model is determined. According to the method for determining an inverse of gravity correlation time provided in the present invention, a forward and backward Kalman filter during data processing on gravity measurement of moving bases can be adjusted, to obtain a high-precision and high-wavelength-resolution gravity anomaly value.

The disclosure presents processes to locate one or more quantum gravimeters at a hydrocarbon well site, with at least one quantum gravimeter at a surface location. Zero or more additional gravimeters, whether quantum gravimeters or non-quantum gravimeters, can be located downhole a wellbore of the well site. Gravitational data collected from various gravimeters can be analyzed to produce analyzed gravitational parameters and subterranean formation parameters. In some aspects, the gravitational data can be processed, such as by an inversion algorithm or a noise reduction algorithm. The generated results can be used to calibrate non-quantum gravimeters located proximate the well site or downhole the wellbore, identify a depth and direction of a water front, identify the fluid flow of hydrocarbons or water in the subterranean formation, to identify orphaned hydrocarbon reservoirs, or other characteristics of fluid flow or subterranean formation parameters, such as subterranean formation damage.

The disclosure presents processes to locate one or more quantum gravimeters at a hydrocarbon well site, with at least one quantum gravimeter at a surface location. Zero or more additional gravimeters, whether quantum gravimeters or non-quantum gravimeters, can be located downhole a wellbore of the well site. Gravitational data collected from various gravimeters can be analyzed to produce analyzed gravitational parameters and subterranean formation parameters. In some aspects, the gravitational data can be processed, such as by an inversion algorithm or a noise reduction algorithm. The generated results can be used to calibrate non-quantum gravimeters located proximate the well site or downhole the wellbore, identify a depth and direction of a water front, identify the fluid flow of hydrocarbons or water in the subterranean formation, to identify orphaned hydrocarbon reservoirs, or other characteristics of fluid flow or subterranean formation parameters, such as subterranean formation damage.

Provided are apparatus and methods for generating a representation of a physical environment, comprising: a mobile sensor platform (MSP) including sensors that output sensor signals relating to parameters such as range, gravity, direction of the Earth's magnetic field, and angular velocity. The MSP is adapted to be moved through the environment. The sensor signals are processed and observations of axes in the environment are generated for a sequence of time steps, the orientation of the MSP is estimated for each of the time steps, observed axes are identified at each orientation, and similar axes are associated. The orientations, the axes in the environment, and the directions of gravity and the Earth's magnetic field are linked such that each observation is predicted based on the estimates of the orientations. An estimate of the orientations is optimized and an output of the representation of the physical environment is generated based on the optimized orientation estimates. The output may be an axis map, a visual representation, and/or a data set. In one embodiment the output device may produce an output comprising a stereonet.