An x-ray-based borehole fluid evaluation tool for evaluating the characteristics of a fluid located external to said tool in a borehole using x-ray backscatter imaging is disclosed, the tool including at least an x-ray source; a radiation shield to define the output faun of the produced x-rays into the borehole fluid outside of the tool housing; at least one collimated imaging detector to record x-ray backscatter images; sonde-dependent electronics; and a plurality of tool logic electronics and power supply units. A method of using an x-ray-based borehole fluid evaluation tool to evaluate the characteristics of a fluid through x-ray backscatter imaging is also disclosed, the method including at least producing x-rays in a shaped output; measuring the intensity of backscatter x-rays returning from the fluid to each pixel of one or more array imaging detectors; and converting intensity data from said pixels into characteristics of the wellbore fluids.

An x-ray based litho-density tool for measurement of formation surrounding a borehole is provided, the tool including at least an internal length comprising a sonde section, wherein said sonde section further comprises an x-ray source; at least one radiation measuring detector; at least one source monitoring detector; a plurality of sonde-dependent electronics; and a reference detector, wherein the reference detector is used to monitor the output of the x-ray source such that the reference detector's output effects corrections to the outputs of the detectors used to measure the density of the materials surrounding the borehole in order to correct for variations in the x-ray source output. Tool logic electronics, PSUs, and one or more detectors used to measure borehole standoff such that other detector responses maybe compensated for tool standoff are also provided. Shielding, through-wiring; wear-pads that improve the efficacy and tool functionality are also described and claimed.

An x-ray based litho-density tool for measurement of formation surrounding a borehole is provided, the tool including at least an internal length comprising a sonde section, wherein said sonde section further comprises an x-ray source; at least one radiation measuring detector; at least one source monitoring detector; a plurality of sonde-dependent electronics; and a reference detector, wherein the reference detector is used to monitor the output of the x-ray source such that the reference detector's output effects corrections to the outputs of the detectors used to measure the density of the materials surrounding the borehole in order to correct for variations in the x-ray source output. Tool logic electronics, PSUs, and one or more detectors used to measure borehole standoff such that other detector responses may be compensated for tool standoff are also provided.

Shielding, through-wiring, wear-pads that improve the efficacy and tool functionality are also described and claimed.

Through-tubing, cased-hole sealed material density can be evaluated using gamma ray measurements. Density evaluation comprises detecting, by at least one detector positioned within a casing of a wellbore including a sealing material positioned between the casing and a subsurface formation, electromagnetic radiation generated in response to nuclear radiation being emitted outward toward the subsurface formation, determining an electromagnetic radiation count based on the detected electromagnetic radiation, selecting at least one of a first reference material having a density that is less than a density of the sealing material and a second reference material having a density that is greater than the density of the sealing material, adjusting the electromagnetic radiation count based on the density of the at least one of the first reference material and the second reference material, and determining a density of the sealing material based on the adjusted electromagnetic radiation count.

In one aspect, a system (5) for use in providing an approximation or estimation of a characteristic (for example, a bulk density value) of a deposit subject to a drilling operation is disclosed. In one form, the system (5) comprises a processor module (25) arranged in operable association with a network of sensors (30) operable for measuring one or more parameters relating to the operation of the drilling assembly (10). The processor module (25) is configured operable for receiving data/information derived from the network of sensors (30), and processing the data/information so as to provide a representation of the incursion (eg. depth of penetration into the relevant deposit) achieved by way of the drilling assembly (10). The processor module (25) is further configured for processing the representation of the incursion with a predetermined relationship that is characteristic of, or unique to, the drilling assembly (10) for providing or allowing an approximation/estimation of the characteristic of the deposit as a function of one or more parameters of the incursion to be made.

Casing condition is an important concern to oilfield operators. Systems and methods are disclosed herein for using neutron logging tools to measure casing condition, using windows in the gamma energy spectrum that are sensitive and insensitive to casing condition to obtain a ratio having a value that ranges between one extreme representative of completely absent casing and an opposite extreme representative of casing in good condition. The sensitive (“divergence”) window may be positioned at or near 7.65 MeV, the characteristic energy of gamma rays from a neutron capture event by an iron nucleus. The insensitive (“consistency”) window is preferably adjacent to the divergence window with a comparable size to the divergence window. A suitable division point between the windows may be about 6.25 MeV.

A radiation generator may include an elongate generator housing having a proximal end and a distal end, a target electrode within the elongate generator housing at the distal end thereof, a charged particle source within the elongate generator housing at the proximal end thereof to direct charged particles at the target electrode. A plurality of accelerator electrodes may be spaced apart within the elongate generator housing between the target electrode and the charged particle source to define a charged particle accelerator section. Each accelerator electrode may include an annular portion having a first opening therein, and a frustoconical portion having a base coupled to the first opening of the annular portion and having a second opening so that charged particles from the charged particle source pass through the first and second openings to reach the target electrode.

A method and system for estimating density of material surrounding a borehole in mineral exploration, the method including inserting a tool into a drilling rod located within a borehole, the tool having a gamma radiation source and at least one sensor; raising the tool within the drilling rod; receiving gamma count readings at the at least one sensor; sending the gamma count readings to a computing device; and removing effects of the drilling rod from the gamma count readings at the computing device to calculate a density of material surrounding the borehole.

This disclosure provides a downhole drilling tool that has a deep-reading logging tool, a near-bit resistivity tool, and a gamma ray detector. Formation information logged using the deep-reading logging tool is used to build a preliminary stratigraphic model with a relatively low resolution. The preliminary stratigraphic model is further refined using data logged using the near-bit resistivity tool and/or the gamma ray detector to obtain a refined stratigraphic model with a higher resolution. The model is used to guide geosteering to achieve better well placement and trajectory control.

A method of creating three-dimensional borehole data is provided, including illuminating a borehole using collimated beams of electromagnetic radiation; rotating the collimated beams in a sweep of at least 360 degrees; detecting backscattered electromagnetic radiation returned from surfaces of associated illumination planes using electromagnetic radiation sensors; converting detected radiation into a corresponding set of volume image data; analyzing the volume image data using computational visualization processing techniques; and creating a three-dimensional image representative of the volume data. Imaging methodologies include a complete, radial conic-shaped surface while the imaging system remains stationary; a plurality of scans performed while longitudinally moving the imaging system a distance d through the borehole between image capture operations; and a plurality of scans performed while longitudinally moving the imaging system a distance d, where d is a distance less than or equal to the collimated beam thickness, so that adjacent scans partially overlap.