A measuring device for measuring a hole in the ground having at least one measuring probe having at least one measurement signal transmitter to transmit a measurement signal, at least one measurement signal receiver to receive the measurement signal reflected on a wall area of the hole, and an evaluation unit for determining a wall distance between the measurement signal transmitter and the wall area of the hole, wherein a measuring distance based on an assignment rule can be assigned to the received, reflected measurement signal. A calibrating device having at least one calibration element. The measurement signal transmitter transmits a calibration signal, which can be reflected on the calibration element, wherein the measurement signal receiver receives the calibration signal reflected on the calibration element. The evaluation unit changes and calibrates the assignment rule based on the calibration signal reflected and received by the calibration element.

Systems and methods for drilling a borehole into the earth are provided. The systems and methods include drilling a first portion of a borehole with a drilling system comprising a disintegrating device, the first portion extending from the surface to a subsurface reference point, wherein steering within the first portion is performed based on a first coordinate system with a first origin, creating a second coordinate system, wherein the second coordinate system has a second origin that is related to subsurface reference point, and drilling a second portion of the borehole with the drilling system, wherein steering within the second portion is performed based on the second coordinate system.

A technique facilitates use of acoustic measurements to enable geo-steering during a well operation. A steerable well string is provided with acoustic systems used to collect data which is then processed to determine geo-steering inputs. In some applications, the well string may comprise a coiled tubing drilling tool. The coiled tubing drilling tool or other well string tool is combined with an azimuthally distributed pitch-catch micro-sonic sensor system and an azimuthally distributed ultrasonic pulse-echo transducer system. Data from these two systems is provided to a processing system which processes the data to determine, for example, real-time, geo-steering inputs. These inputs may then be used to more effectively steer the coiled tubing drilling tool or other well string tool.

A method for borehole measurements may comprise receiving one or more signals from a linear receiver array, computing an arctan of a Hilbert Transform, isolating a first arriving energy, selecting a reference instantaneous phase on a reference receiver, finding the reference instantaneous phase for the linear receiver array, computing a relative travel time shift, combining a reference pick time with a relative time, and determining a travel time. A system for borehole measurements comprise a conveyance, a bottom hole assembly attached to the conveyance, a linear receiver array, wherein the linear receiver array is disposed on the bottom hole assembly, and a computer system connected to the linear receiver array.

A method for borehole measurements may comprise receiving one or more signals from a linear receiver array, computing an arctan of a Hilbert Transform, isolating a first arriving energy, selecting a reference instantaneous phase on a reference receiver, finding the reference instantaneous phase for the linear receiver array, computing a relative travel time shift, combining a reference pick time with a relative time, and determining a travel time. A system for borehole measurements comprise a conveyance, a bottom hole assembly attached to the conveyance, a linear receiver array, wherein the linear receiver array is disposed on the bottom hole assembly, and a computer system connected to the linear receiver array.

A method for acoustic geosteering in directional drilling is provided. The method includes measuring a response from a fiber-optic distributed acoustic sensor disposed on a bottom hole assembly and determining a location of the bottom hole assembly from seismic waves received from surface sources. A subterranean layer structure proximate to the bottom hole assembly is determined from reflections of a locally generated soundwave. Adjustments to geosteering vectors for the bottom hole assembly are determined based, at least in part, on the location and the subterranean layer structure.

A method of monitoring hydraulic fracturing using DAS sensors in a treatment well and/or observation well is described. The raw data is transformed using a low pass filter (≦0.05 Hz) and down-sampled to show the signal as the stimulation progresses. The resulting data can be used to optimize the hydraulic fracturing or improve reservoir models for other reservoirs.

Disclosed are tools, systems, and methods for detecting one or more underground acoustic sources and localizing them in depth and radial distance from a wellbore, for example, for the purpose of finding underground fluid flows, such as may result from leaks in the well barriers. In various embodiments, acoustic-source detection and localization are accomplished with an array of at least three acoustic sensors disposed in the wellbore, in conjunction with array signal processing.

Basin-wide modeling is utilized to improve confidence of source rock presence and quality estimation. A 4D basin model incorporates geological model, geochemical models, and resettlement model for a region. Utilizing the 4D basin model provides consistency of internal data, geology-constrained basin-wide calculations, capability to capture local controls to allow basin-specific interpretations, reduction of reliance on empirical relationships, and capability to investigate source rock development through time.

Basin-wide modeling is utilized to improve confidence of source rock presence and quality estimation. A 4D basin model incorporates geological model, geochemical models, and resettlement model for a region. Utilizing the 4D basin model provides consistency of internal data, geology-constrained basin-wide calculations, capability to capture local controls to allow basin-specific interpretations, reduction of reliance on empirical relationships, and capability to investigate source rock development through time.