49 results about "Gamma ray logging" patented technology

A gamma ray logging system and a method of calibrating a detected gamma radiation spectrum. The gamma ray logging system includes a gamma ray detector for detecting gamma radiation, an analyzer for generating a detected gamma radiation spectrum from the detected gamma radiation, and a processor which is configured to perform a calibration of the detected gamma radiation spectrum. The method of calibrating the detected gamma radiation spectrum includes selecting at least two data points from the detected gamma radiation spectrum, determining a mathematical relationship from the selected data points, and using the mathematical relationship to generate a calibrated gamma radiation spectrum from the detected gamma radiation spectrum.

A method for determining concentrations of naturally occurring radioactive elements in earth formation by analysis of gamma ray energy spectra measured by at least one gamma ray detector while the borehole is being drilled. Gain of the gamma ray detector is controlled automatically through analysis of the spectra. The one or more gamma ray detectors are disposed at the periphery of the downhole instrumentation to maximize sensitivity. Elemental concentrations of naturally occurring radioactive elements such as potassium, uranium and thorium are measured either as a function of depth in the borehole, or as a function of aximuthal sectors around the borehole wall, or as a function of both depth and azimuthal sectors.

A neutron source for a downhole logging tool includes 241Am and 9Be. Stainless steel shielding is used to control the generation of neutrons by the source. The device may be used for both continuous as well as pulsed neutron logging and may also be used for gamma ray logging.

Elemental analysis of an earth formation (including Aluminum) is obtained using measurements from a gamma ray logging tool. The inelastic spectrum of Aluminum is determined from measurements made in a water tank. From the elemental analysis, an estimate of the mineralogy of the formation is made treating the problem as one of Linear Programming (maximizing an objective function subject to equality and / or inequality constraints.

Elemental analysis of an earth formation is obtained using measurements from a gamma ray logging tool. From the elemental analysis, an estimate of the Calcium, Magnesium and Carbon content of the formation is determined. The amount of organic carbon in the formation is estimated from the total Carbon content and the inorganic carbon associated with minerals in the formation. An indication of source rock may be obtained from the Th / U ratio. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b)

Disclosed is a method for calculating a shale content of high and low gamma interaction reservoirs. The method includes step one, influencing correction by means of a logging information environment; step two, calculating the shale content by means of spontaneous potential logging; step three, calculating the shale content by means of resistivity logging; step four, calculating the shale content by means of a compensated neutron-density method; step five, calculating the shale content by means of natural gamma-ray logging; step six, determining the shale content using a minimum value method on the basis of the shale contents calculated by using the previous four methods. According to the method for calculating the shale content of the high and low gamma interaction reservoirs, shale content calculations of a high gamma reservoir and a conventional reservoir are organically integrated, a calculated shale content curve basically overlaps with a shale content analyzed and tested by a lab, and accuracy of calculation of the shale content is greatly increased.

Elemental analysis of an earth formation is performed using measurements from a gamma ray logging tool. From the elemental analysis, an estimate of the mineralogy of the formation is made. A prediction of the capture cross-section of the formation is made using the mineralogical analysis. The difference between the predicted capture cross-section and a measured capture cross-section is an indication of gas in the formation.

The invention provides a method for identifying high-quality shale by using logging information, and belongs to the field of oil and gas exploitation and physical geography. The method comprises: firstly performing pre-processing on logging information, including performing environment correction, depth correction, and standardization; then performing the following steps: step 1, using a natural gamma-ray logging curve to distinguish a shale bed and a non-shale bed; step 2, using the ratio of a thorium curve and a potassium curve of natural gamma-ray spectrometry log and ratio of the thorium curve and the potassium curve to distinguish sedimentary environment of the shale bed; step 3, if the sedimentary environment distinguished in the step 2 is reduction and low-energy environment, calculating contents of organic matters and clay minerals in the shale bed; step 4, and on the basis of the step 3, identifying high-quality shale beds and non-high-quality shale beds.

The invention relates to a technology for calculating a horizontal well oil reservoir development stratum true dip angle so as to correct an oil reservoir top surface micro structure, and particularly relates to a method for correcting the oil reservoir top surface micro structure by using information of a horizontal well stratum penetrating point. The method comprises the steps of determining the length of a delay interval by using delayed response characteristics of a natural gamma-ray logging curve when penetrating through a sand shale boundary, deducing and calculating a more accurate calculation method for a stratum true dip angle of the horizontal well stratum penetrating point by being combined with a well drilling inclination angle and an azimuth angle explained in the logging process, drawing a stratum dip angle plane graph, correcting the horizontal well oil reservoir top surface micro structure by taking the stratum dip angle plane graph as a basis, drawing a contour map with the spacing being less than 2m, and guiding reasonable development of an oil reservoir and potential tapping of residual oil. The method provided by the invention overcomes limitations in carrying out correction on the top surface micro structure by only using well point altitude and seismic data at present, provides a method for correcting horizontal well oil reservoir development top surface micro structure, makes full use of the information of the horizontal well stratum penetrating point, and acquires the true stratum dip angle, thereby studying the oil reservoir top surface micro structure more accurately.

The invention discloses a method and a device for determining distance between a bit and a formation interface in geosteering while drilling. The method includes the steps of acquiring documents of natural gamma-ray logging in position while-drilling in real time and predicting the relative included angle between the formation interface to be drilled and the drilling direction, acquiring the vertical distance between the preset position in the drilling direction and the formation interface to be drilled, and determining the distance from the bit to the formation interface to be drilled in the drilling direction according to the relative included angle and the vertical distance. The preset position is the position of a detector in the location of the natural gamma-ray curve varies at first when the bit drills to the formation interface to be drilled. According to the documents of the natural gamma-ray logging in position-while-drilling, the distance between the bit and the formation interface to be drilled is quantized, and thus, natural gamma-ray logging in position-while-drilling can facilitate geosteering well.

Resolution of thin beds made by a natural gamma ray logging tool is improved using a relation between the width of the response and the bed thickness. The peak gamma ray of the bed is determined using another relation between the measured gamma ray response and the bed thickness.

The invention relates to a well completion method with shale gas layer radial jetting drilling and volume fracturing combined. According to the method, a magnetic locating and natural gamma-ray logging method is utilized, and a gyroscope is utilized for measuring a hole drift angle, so that the opening specific direction of a casing pipe is determined; then, a milling bit is utilized for windowing the determined casing pipe, and at least two radial horizontal holes are drilled through high-pressure jet injection; the radial horizontal holes are all located in a target stratum, and are evenly distributed; and finally, fracturing fluid is input to a high-pressure pump, and a rock crack needed by oil and gas transportation is formed. The method has the beneficial effects that the shale gas single-well gas production rate is improved, after-pressure returning and draining and environment protection are facilitated, the single-well work cost and the risks are greatly reduced, and the method has the prominent advantages from the technology, the environment and the economy.

The present invention relates to a method for executing annular space log by neutron gamma-ray log instrument in tracing gadolinium between wells, includes trifluoro three ethylene diamine gadolinium complex compound taken as tracer, confects water solution of trifluoro three ethylene diamine gadolinium complex compound, and injects the solution into water injection well. Gathering water solution sample from effluent in each oil production well, and measuring gadolinium content with mass spectrography in sample; before gadolinium does not arrive at oil well, annular space log is executed and well logging baseline is obtained; when gadolinium content of the sample is upwardly mobile, oil well is in annular space log by using annular space neutron gamma-logging instrument; variation curve of gamma count in layers changed with times is measured, obtaining water-bearing saturation degree, obtaining horizontal distribution of remaining oil saturation, obtaining longitudinal distribution of remaining oil saturation and obtaining horizontal distribution of each reservoir remaining oil saturation. The method decreases well logging number, does not affect oil production, can obtain horizontal distribution and longitudinal distribution of remaining oil saturation, and can obtain horizontal distribution of each reservoir remaining oil saturation.

Elemental analysis of an earth formation is obtained using measurements from a gamma ray logging tool. From only the elemental analysis and measurements of porosity, density and natural gamma rays, an estimate of the mineralogy of the formation is made treating the problem as one of minimizing a quadratic objective function subject to equality and / or inequality constraints.

The invention relates to evaluation of the brine grade in underground brine exploration and development, in particular to a method for obtaining the sandstone brine layer potassium ion content by means of natural gamma-ray logging. The method comprises the following steps that 1) geophysical well logging is carried out on a stratum to be explained, and the geophysical well logging comprises lithological class logging, physical property class logging and natural gamma-ray spectra logging; 2) a sandstone layer and pure mudstone are divided, shaliness Vsh of the sandstone layer is evaluated; 3) porosity phi of the sandstone layer is calculated, and the sandstone brine layer and a dry sand layer are divided; 4) the sandstone brine layer potassium total content K, the potassium content Ksh of the pure mudstone near the sandstone brine layer, and the potassium content Kma of the dry sand layer near the sandstone brine layer are obtained by means of natural gamma-ray logging information; 5) the potassium ion mass concentration of the sandstone brine layer is evaluated. The method is a brand new method for evaluating the potassium ion content in deep well brine, precision is high, and well logging interpretation requirements of the potassium ion content are met.

The invention provides a porosity interpretation method based on the condition of tight oil reservoir variable skeleton parameter. The porosity interpretation method based on the condition of the tight oil reservoir variable skeleton parameter comprises the steps that core of the tight oil reservoir is restored first, effective analysis data of the effective core porosity of the tight oil reservoir is selected, the clay mineral content, rock constituents (arenaceous, calcareous and dolomitic are included mainly) and the porosity characteristics in the tight oil reservoir of the effective core and the corresponding responding characteristics of natural gamma-ray logging relative parameter (delta GR), acoustic travel time logging parameter (delta t), density logging parameter (Rho b) and neutron logging parameter (phi N) are contrastively analyzed, the affect of the oil-bearing property of the tight oil reservoir for the logging parameter is ignored, a porosity logging interpretation model based on the condition of the tight oil reservoir variable skeleton parameter is built, and a porosity logging interpretation method to be determined under the condition of tight oil reservoir variable skeleton parameter is formed. The porosity interpretation method based on the condition of the tight oil reservoir variable skeleton parameter is helpful to improve the tight oil reservoir porosity logging interpretation precision.

The invention discloses an inclined-well dual laterolog curve correction method. The method includes the steps: S1, building an inclined-well dual laterolog forward model; S2, performing forward simulation to determine stratum dip angle and thickness threshold of a target stratum; S3, according to measured dual laterolog data, integrating natural gamma ray logging, imaging and dip logging data for stratum stratification and stratum dip angle determination, and combining with forward result to determine whether data correction needs to be performed or not; S4, if yes, extracting resistivity representative value of the target stratum according to stratification result, and constantly updating stratum resistivity model parameters to enable an error between a dual laterolog value and a measure logging value at a central point of a reconstructed stratum; S5, utilizing a stratum reflectivity value to perform forward simulation of dual laterolog response under straight well condition, adding other environmental influencing factors, and acquiring a dual laterolog curve under the straight well condition. The method is conducive to solving the problem of electric logging based on dual laterolog data and under inclined well condition.

Elemental analysis of an earth formation is obtained using measurements from a gamma ray logging tool. From the elemental analysis, an estimate of the carbon content and the sulfur, vanadium, nickel, titanium and / or molybdenum content of the formation is determined. A table look-up is used to estimate the viscosity from the elemental composition.

The invention belongs to the technical field of geophysical prospecting and relates to an electromagnetic logging device and method, in particular to a hand push type device and method for time domainelectromagnetic logging in a coal mine underground borehole. In-hole transmitting and receiving devices with identical-diameter transmitting coils are wound on the rear portion of a probe, a multi-joint carbon fiber rod is used for pushing the device into the coal mine underground borehole, time domain rectangular wave current in a duty ratio of 50% is supplied into the transmitting coils to realize measurement of borehole radial rock electrical property variation. By adoption of the method, one-dimensional electrical property variation curves of rocks can be obtained while borehole radial two-dimensional apparent restivity distribution can be obtained through a data processing technique, and stratigraphic division and lithologic identification accuracy of the borehole can be remarkably improved by natural gamma-ray logging.

A natural gamma tag marking materials for sub or permanent markers used in gamma logging operations, such natural gamma materials having a gamma count of between 200 and 1000 counts per second. The instant invention further discloses a typical Sub, for insertion in a drilling operation, utilizing natural gamma element compounds which are considered to be non-hazardous and effective as tag markers when used in wire-line logging operations.

Disclosed is a method for calculating a shale content of high and low gamma interaction reservoirs. The method includes step one, influencing correction by means of a logging information environment; step two, calculating the shale content by means of spontaneous potential logging; step three, calculating the shale content by means of resistivity logging; step four, calculating the shale content by means of a compensated neutron-density method; step five, calculating the shale content by means of natural gamma-ray logging; step six, determining the shale content using a minimum value method on the basis of the shale contents calculated by using the previous four methods. According to the method for calculating the shale content of the high and low gamma interaction reservoirs, shale content calculations of a high gamma reservoir and a conventional reservoir are organically integrated, a calculated shale content curve basically overlaps with a shale content analyzed and tested by a lab, and accuracy of calculation of the shale content is greatly increased.

The invention discloses coal petrography water-acid high-pressure presplitting, softening, impact prevention and permeability improvement complete equipment and method. The complete equipment comprises a drilling system, a measuring and control system, a hole sealing system, and a water-acid coupling pressurizing system; the drilling system comprises an underground drill rig, a drill rod and a drill bit; the measuring and control system comprises a gamma ray logger and a drilling peeper for recording drilling position parameters, lithology and fracture development conditions and detecting a presplitting effect; the hole sealing system comprises a segmented fracturing hole sealer; and the water-acid coupling pressurizing system comprises a high-pressure water pump assembly, a gas booster pump assembly, a gas-water mixing pipe assembly and a porous parallel liquid supply pipe network. The complete equipment merges water injection and acid injection; a high-pressure carbon dioxide injecting pump is added; carbon dioxide gas is directly injected in a high-pressure gas and water mixing pipe; acid is injected after pumping, so that corrosion of a high-pressure water pump by acid is prevented, and high-pressure acid injection is implemented; the water pump is singly opened to implement hydraulic fracturing; the carbon dioxide injecting pump is singly opened to implement high-pressuregas splitting; and the two are opened at the same time to implement acid fracturing.