摘要:
A method and composition for distinguishing native hydrocarbons in a formation from oil-based drilling fluid with nuclear magnetic resonance (NMR) is provided so that NMR may be used in analyzing formation fluids from boreholes drilled with oil-based drilling fluids. In the method, the drilling fluid is doped with oil solubilized paramagnetic species before or during drilling of the borehole. The paramagnetic species cause a shift in the T1 and T2 NMR response of the drilling fluid.
摘要:
The pressure reading tool includes a housing with an interior chamber and an orifice extending from the chamber to the exterior of the housing. A pulse member with a magnetostrictive ring and an excitation source are disposed within the chamber to produce a highly agitated fluid discharge through the orifice. The magnetostrictive ring, chamber volume, and orifice cooperate to induce Helmholtz resonance frequencies in the fluid in the chamber to thereby enhance the agitation of the fluid discharge. A sheathing encapsulates the pulse member to protect it from contact with the fluid. A dampening element is also interposed between the pulse member and housing to isolate vibration.
摘要:
Methods for recovering a LWD or MWD data signal in the presence of mud pump noise are provided and generally comprise calibrating the drilling mud pressure as a function of the mud pump piston position, and then tracking the piston position during transmission of the LWD or MWD data signal and using the calibration information to subtract out the mud pump noise. Calibration is accomplished in the absence of the LWD or MWD data signal to provide a correlation between mud pump piston position and the drilling mud pressure. Then, when the LWD or MWD data signal is being generated, the mud pump piston position is tracked such that the pressure due to the pump can be subtracted and the LWD or MWD signal recovered. Where a plurality of mud pumps are being utilized, calibration is accomplished by running the mud pumps together in the absence of the LWD or MWD data signal, and processing the received mud pressure signals in the Fourier domain to allocate respective portions of the mud pressure signals to respective mud pumps such that each mud pump is provided with a signature as a function of its own piston position. With the piston position of each mud pump being tracked, the sum of the mud pressure signals generated by the mud pumps based on their piston positions is subtracted from the total received signal to recover the LWD or MWD signal.
摘要:
An apparatus is disclosed for generating a magnetic field of high field strength, spatial uniformity and minimal drift of magnetic field intensity over a temperature range of about 0° C. to 175° C. This apparatus may be used in a standard modular logging tool for direct downhole NMR measurements of various parameters of fluid samples of geologic formations near the walls of a borehole. In one embodiment, the apparatus is composed of two tubular permanent magnets made of different magnetic materials with different magnetic temperature coefficients to provide temperature compensation. The apparatus preferably also utilizes a pressure barrel that surrounds the magnets and provides a return path for magnetic flux lines, thereby increasing flux density within the measurement volume.
摘要:
An apparatus is disclosed for generating a magnetic field of high field strength, spatial uniformity and minimal drift of magnetic field intensity over a temperature range of about 0° C. to 175° C. This apparatus may be used in a standard modular logging tool for direct downhole NMR measurements of various parameters of fluid samples of geologic formations near the walls of a borehole. In one embodiment, the apparatus is composed of two tubular permanent magnets made of different magnetic materials with different magnetic temperature coefficients to provide temperature compensation. The apparatus preferably also utilizes a pressure barrel that surrounds the magnets and provides a return path for magnetic flux lines, thereby increasing flux density within the measurement volume.
摘要:
An NMR measurement-while-drilling tool having the mechanical strength and measurement sensitivity to perform NMR measurements of an earth formation while drilling a borehole, and a method and apparatus for monitoring the motion of the measuring tool in order to take this motion into account when processing NMR signals from the borehole. The tool has a permanent magnet with a magnetic field direction substantially perpendicular to the axis of the borehole, a steel collar of a non-magnetic material surrounding the magnet, antenna positioned outside the collar, and a soft magnetic material positioned in a predetermined relationship with the collar and the magnet that helps to shape the magnetic field of the tool. Due to the non-magnetic collar, the tool can withstand the extreme conditions in the borehole environment while the borehole is being drilled. Motion management apparatus and method are employed to identify time periods when the NMR measurements can be taken without the accuracy of the measurement being affected by the motion of the tool or its spatial orientation.
摘要:
Apparatus and method for providing in-situ data of formation fluids at true reservoir conditions. The apparatus has NMR chamber of the flow-through type, so it is no longer necessary to divert a sample for the basic NMR analysis or transfer it uphole for laboratory analysis. The apparatus is preferably modular and is compatible with wireline tools configurable for a variety of sampling, testing and monitoring purposes. Fluid properties such as viscosity can be derived from diffusivities and relaxation times, as measured by NMR. Additional accuracy is provided in the downhole sampling process, and in the interpretation of NMR logs in real time at true reservoir conditions.
摘要:
The pressure reading tool includes a housing with an interior chamber and an orifice extending from the chamber to the exterior of the housing. A pulse member with a magnetostrictive ring and an excitation source are disposed within the chamber to produce a highly agitated fluid discharge through the orifice. The magnetostrictive ring, chamber volume, and orifice cooperate to induce Helmholtz resonance frequencies in the fluid in the chamber to thereby enhance the agitation of the fluid discharge. A sheathing encapsulates the pulse member to protect it from contact with the fluid. A dampening element is also interposed between the pulse member and housing to isolate vibration.
摘要:
Nuclear magnetic resonance well logging apparatus and method of use for geophysical examination of a borehole as the borehole is drilled. The apparatus is connected to the drill bit to follow it through the borehole as the borehole is formed. The apparatus comprises a non-magnetic protective collar with lateral protrusions or wings, which provide enhanced abrasion resistance, strength, and rigidity to the probe section. This collar is twisted about its longitudinal axis. The apparatus also comprises one or more permanent magnets within the metal collar and an antenna mounted outside of the collar. Both the magnet and the antenna are twisted about the longitudinal axis of the probe section to produce a generally helical static magnetic field and a radio frequency magnetic field that is substantially orthogonal to the static magnetic field.
摘要:
A device, method, and system for creating a pressure pulse from drilling fluid within a drill string in a down hole drill collar for enabling measurement-while drilling. The device and system are designed such that primarily laminar flow exists in the area surrounding the pulser apparatus. The method associated with the reproducible and essentially noise-free pulses occurs when a pulser bell is manipulated in an upward and downward direction by a combination of the solenoid activation of a bi-directional poppet to redirect the fluid flow from the pressure reservoir to and from a sliding pressure chamber and associated upper and lower flow connecting channels. The pulse or non-pulse is converted into a digital signal uphole by a pressure transducer in conjunction with a decoding algorithm. It is then displayed to the driller and oilfield operators as useful directional and formation information that help the oilfield operator for uphole decision making regarding directional drilling. Additional pulsers can be added to the tool so that higher data bit rates can be accomplished. These higher data bit rates will provide for more comprehensive data collection thereby reducing drilling costs and optimizing oil field yields. The higher bit rate allows for more sensors that can send additional and improved information uphole without the use of open hole wire line logging which is impossible to accommodate while drilling horizontally. Disclosed is a concentric, stream-line centralizer device, secured inside a drill collar and fastened to a measurement while drilling device, wherein a drilling fluid moves with a laminar flow within the drilling collar.