Abstract: A system is provided for detecting the presence of formation gas in a stream of drilling fluid flowing through a wellbore during drilling of the wellbore. The system has at least one sensor chamber connectable to a drill string for drilling the wellbore, each sensor chamber containing a volume of a selected gas and having a membrane wall which allows passage of formation gas from the stream of drilling fluid into the sensor chamber. The sensor is arranged to detect a change of a selected characteristic of the volume of gas due to passage of formation gas from the stream of drilling fluid via the membrane wall into the sensor chamber.

Abstract: Aspects of this invention include a rotary steerable steering tool having a sensor arrangement for measuring downhole dynamic conditions. Rotary steerable tools in accordance with this invention include a rotation rate measurement device disposed to measure a difference in rotation rates between a drive shaft and an outer, substantially non-rotating housing. A controller is configured to determine a stick/slip parameter from the rotation rate measurements. Exemplary embodiments may also optionally include a tri-axial accelerometer arrangement deployed in the housing for measuring lateral vibrations and bit bounce. Downhole measurement of stick/slip and other vibration components during drilling advantageously enables corrective measures to be implemented when dangerous dynamic conditions are encountered.

Abstract: A method for pore pressure prediction. The method includes obtaining a stress sensitivity coefficient, obtaining a compressional wave (P-wave) velocity and a shear wave (S-wave) velocity for a pre-drill location and obtaining a first predicted pore pressure. Further, the method includes iteratively performing calculating a total stress value associated with the pre-drill location using the first predicted pore pressure associated with the pre-drill location, and calculating a second predicted pore pressure associated with the pre-drill location using a stress-pressure relationship equation, a stress-velocity relationship equation, the stress sensitivity coefficient, a reference location, and at least one selected from a group consisting of the P-wave velocity and the S-wave velocity for the pre-drill location, and adjusting a drilling operation associated with the pre-drill location, based on the second predicted pore pressure.

Abstract: An apparatus and method for determining at least one downhole formation property is disclosed. The apparatus includes a probe and a pretest piston positionable in fluid communication with the formation, and a series of flowlines pressure gauges, and valves configured to selectively draw into the apparatus for measurement of one of formation fluid and mud. The method includes performing a first pretest to determine an estimated formation parameter; using the first pretest to design a second pretest and generate refined formation parameters whereby formation properties may be estimated.

Abstract: An optical fiber extends down hole from an OFDR. A first set of sensors with a centrally-located reference reflector is disposed over a first fiber length, and a second set of sensors with a centrally-located reference reflector is disposed over a second fiber length. The sensors of the first and second sensing lengths are positioned at slightly offset positions from the reference reflectors so as to interleave the reflected signals. Additional sensing lengths may be similarly interleaved. The system is used by sending an optical signal along the optical fiber, detecting a reflected optical signal, separating the optical signal into component signals, and extrapolating a well condition therefrom. Another method includes creating a low frequency signal component in a reflected optical signal by placing at least one sensor beyond a Nyquist sampling distance limit, detecting the low frequency signal component, and extrapolating a well condition therefrom.

Abstract: Geophysical measurement system employed during the drilling of a well borehole. The system employs a reference clock disposed within equipment at the surface of the earth and a borehole assembly which houses a downhole clock and at least one sensor. The borehole assembly is operationally connected to a drill string, which advances the borehole. At least one synchronization shuttle apparatus containing a shuttle clock is conveyed downhole to the borehole assembly to synchronize the borehole clock with the reference clock. Reference and borehole clock synchronization is maintained at one millisecond or less over a period of days. Outputs from the reference clock and borehole clock and sensor are combined to obtain a measure of a geophysical parameter of interest. Although the measurement system is particularly applicable to seismic-while-drilling measurements, it can be used in a wide variety of clock driven geophysical measurements.

Abstract: A novel process and methodology in deterministic formation evaluation is provided. The formation evaluation results can accurately quantify formation attributes, such as clay-volume, clay-bound-water, effective-porosity and water saturation in shaly sands. Total-porosity is determined using porosity-logs, such as density, neutron and sonic logs. After clay-volume and total-porosity are determined, sand volume (quartz, feldspar, mica . . . ) is the remaining part in the bulk formation evaluated, see FIG. 5.

Abstract: A method for determining a borehole azimuth in a borehole is disclosed. In one exemplary embodiment, the method includes acquiring at least one standoff measurement and a tool azimuth measurement at substantially the same time. Such measurements are then processed, along with a lateral displacement vector of the downhole tool upon which the sensors are deployed in the borehole, to determine the borehole azimuth. The computed borehole azimuths may be advantageously correlated with logging sensor data to form a borehole image, for example, by convolving the correlated logging sensor data with a window function. As such, exemplary embodiments of this invention may provide for superior image resolution and noise rejection as compared to prior art LWD imaging techniques.

Abstract: Apparatus and methods for determining suitable displacement fluids for use in subterranean cementing operations, and methods of cementing that use such displacement fluids, are provided. Examples of methods include methods of water-wetting an annulus in a subterranean formation having an oleaginous-external/aqueous-internal fluid disposed on at least a portion of one or more surfaces of the annulus. Another example of a method is a method of using an inverter fluid in a subterranean formation that includes a tubular string disposed therein having an annular region adjacent the outer surface of the tubular string, at least part of the annular region having an oleaginous-external/aqueous-internal fluid on a surface thereof. Another example of a method of the present invention is a method of identifying an inverter fluid to use for inverting an oleaginous-external/aqueous-internal fluid in a subterranean formation.

Abstract: An apparatus and method for drawing fluid from a subterranean formation into a downhole tool positioned in a wellbore penetrating the formation is provided. A probe body is extended from the downhole tool for engagement with the wellbore wall. The probe body has at least one inlet extending therethrough for receiving downhole fluids. At least one packer is positioned on an external end of the probe body and adapted to create a seal with the wellbore wall. The packer has an inner surface defining an aperture therethrough in fluid communication with the at least one inlet, and a peripheral surface. An internal packer support is positioned adjacent the inner surface of the packer, and an external packer support is positioned about the peripheral surface of the packer whereby at least a portion of the at least one packer is supported as it is pressed against the wellbore wall.

Abstract: A method for determining a borehole azimuth in a borehole is disclosed. In one exemplary embodiment, the method includes acquiring at least one standoff measurement and a tool azimuth measurement at substantially the same time. Such measurements are then processed, along with a lateral displacement vector of the downhole tool upon which the sensors are deployed in the borehole, to determine the borehole azimuth. The computed borehole azimuths may be advantageously correlated with logging sensor data to form a borehole image, for example, by convolving the correlated logging sensor data with a window function. As such, exemplary embodiments of this invention may provide for superior image resolution and noise rejection as compared to prior art LWD imaging techniques.

Abstract: A signal transmission connection for a tool string used in exploration and production of natural resources, namely: oil, gas, and geothermal energy resources. The connection comprises first and second annular elements deployed in cooperative association with each other. The respective elements comprise inductive transducers that are capable of two-way signal transmission between each other, with downhole components of the tool string, and with ground-level equipment. The respective inductive transducers comprise one or more conductive loops housed within ferrite troughs, or within ferrite trough segments. When energized, the conductive loops produce a magnetic field suitable for transmitting the signal. The second element may be rotational in drilling applications. The respective elements may be fitted with electronic equipment to aid and manipulate the transmission of the signal. The first element may also be in communication with the World Wide Web.

Abstract: A method of producing images of formations surrounding a borehole, comprises: obtaining values of a first parameter in the borehole as a function of depth and azimuth at a first resolution; obtaining values of a second parameter in the borehole as a function of depth only at a second resolution; establishing a relationship between the first and second parameters at a matched resolution; using the relationship to derive values of the second parameter as a function of depth and azimuth; and producing an image of the second parameter as a function of depth and azimuth using the derived values of the second parameter.

Abstract: Methods and systems for borehole telemetry are disclosed. In one embodiment, a borehole telemetry system includes a coiled tubing string that is located in the borehole. A receiver is coupled to the coiled tubing string. In one possible implementation, the receiver is located inside the coiled tubing string. A transmitter is also coupled to the coiled tubing string. The transmitter generates signals guided for at least a portion of their path by the entire internal cross-section of the coiled tubing string to the receiver.

Abstract: A portable laser system includes a laser unit and a target unit for measuring the length of a series of pipe assemblies. Either the laser unit or the target unit engages a threaded coupling at one end of the pipe assembly and the other unit engages external pipe threads at an opposite end of the pipe assembly. The laser unit includes a resident memory (i.e., the memory moves with the laser unit), so that the laser system can read the length of more than one pipe assembly before downloading the readings to a computer. The computer then compiles the readings in groups of twenty and calculates an anticipated overall length if the pipe assemblies were interconnected as a string of pipes.

Abstract: A method and system of operating an electromagnetic resistivity tool wherein at least one transmitting antenna of the tool is selectively operable at three or more resonant frequencies for better resistivity profiling of a formation.

Abstract: A method and system for monitoring the operation of downhole equipment, such as electrical submersible pumps, is disclosed. The method and system rely on the use of coiled fiber optic sensors, such as hydrophones, accelerometers, and/or flow meters. These sensors are either coupled to or placed in proximity to the equipment being monitored. As the sensor is perturbed by acoustic pressure disturbances emitted from the equipment, the length of the sensing coil changes, enabling the creation of a pressure versus time signal. This signal is converted into a frequency spectrum indicative of the acoustics emissions of the equipment, which can then be manually or automatedly monitored to see if the equipment is functioning normally or abnormally, and which allows the operator to take necessary corrective actions.

Abstract: Exfiltrometer apparatus includes a container for holding soil. A sample container for holding sample soil is positionable with respect to the container so that the sample soil contained in the sample container is in communication with soil contained in the container. A first tensiometer operatively associated with the sample container senses a surface water potential at about a surface of the sample soil contained in the sample container. A second tensiometer operatively associated with the sample container senses a first subsurface water potential below the surface of the sample soil. A water content sensor operatively associated with the sample container senses a water content in the sample soil. A water supply supplies water to the sample soil. A data logger operatively connected to the first and second tensiometers, and to the water content sensor receives and processes data provided by the first and second tensiometers and by the water content sensor.

Abstract: A method of seismic data processing is described in which a particular wavelet is selected from a plurality of wavelets as being most characteristic of a received seismic signal. A subtracted signal can be determined by subtracting a weighted signal of the particular wavelet from the received signal. From the subtracted signal, an additional particular wavelet can be chosen. The process of subtracting a signal and determining an additional particular one of the plurality of wavelets can be repeated until a criterion is met. The method can be repeated at several depths. The resultant spectral analysis can be used to determine, for example, an absorption coefficient.

Abstract: A method of using an everting borehole liner to perform fluid conductivity measurements in materials surrounding a pipe, tube, or conduit, such as a borehole below the surface of the Earth. A flexible liner is everted (turned inside out) into the borehole with an internal pressurized fluid. As the liner displaces the ambient fluid in the borehole into the surrounding formation, the rate of descent of the liner is recorded. As the impermeable liner covers the flow paths in the wall of the hole, the descent rate slows. From the measured descent rate, the flow rates out discrete sections of the borehole are determined.

Abstract: A method for determining virgin formation temperature of earth formations surrounding a borehole is provided. The time duration of drilling fluid circulation and the time after cessation of drilling fluid circulation at the borehole depth regions of interest are tracked. At a particular borehole depth region of interest, fluid flows from the formations into a device in the borehole, and the temperature of the fluid as a function of time with respect to initiation of fluid flow is measured. The thermal history of formations surrounding the particular borehole depth region is modeled for a cooling phase during drilling fluid circulation, a temperature build-up phase after cessation of drilling fluid circulation, and a formation fluid flow phase after initiation of fluid flow. The model and temperature measurements are used to determine a trend of temperature evolution and the virgin formation temperature by extrapolation from the trend.

Abstract: A method of monitoring pore pressure, comprises the steps of: (a) providing downhole in a well a sealable container, (b) sealing in the container a sample of fluid at a baseline pressure and a sample of a formation having an initial pore pressure, (c) measuring the change in pressure of the fluid sample, the pressure of the fluid sample and the pore pressure of the formation sample sealed in the container tending to equalize over time, and (d) estimating the initial pore pressure relative to the baseline pressure from the measured change in fluid sample pressure.

Abstract: A method and apparatus is provided to determine downhole pressures, such as annular pressure and/or pore pressure, during a drilling operation. A bottom hole assembly (BHA) of a downhole tool includes one or more pressure equalizing assemblies capable of registering the pore pressure when the BHA is at rest and in contact with the wellbore, and annular pressure of a wellbore when it is not. Wellbore fluid is permitted to enter the pressure equalizing assembly and register an annular pressure measurement. Once the BHA comes into contact with the wellbore and to rest, fluid communication is established between the pressure equalizing assembly and the formation to generate a pore pressure measurement. The pressure equalizing assembly includes a sliding valve selectively moveable between an open and closed position in response to operation of the BHA so that the desired pressure measurement may be taken.

Abstract: An apparatus (10) and method are disclosed for eliminating a noise signal from at least one source during an acoustic measurement of a subsurface geological formation or borehole. The apparatus (10) includes a longitudinal body for positioning in the borehole and a transmitter (22) supported by the body for transmitting acoustic signals into the formation and borehole. A sensor (23), substantially isolated within the body, is used to detect one or more noise signals and a receiver (24) is carried by the body for receiving acoustic signals traversing the formation and borehole, and for receiving one or more noise signals.

Abstract: Visual probes and methods for placing visual probes into subsurface areas in either contaminated or non-contaminated sites are described. In one implementation, the method includes driving at least a portion of a visual probe into the ground using direct push, sonic drilling, or a combination of direct push and sonic drilling. Such is accomplished without providing an open pathway for contaminants or fugitive gases to reach the surface. According to one implementation, the invention includes an entry segment configured for insertion into the ground or through difficult materials (e.g., concrete, steel, asphalt, metals, or items associated with waste), at least one extension segment configured to selectively couple with the entry segment, at least one push rod, and a pressure cap. Additional implementations are contemplated.

Abstract: A method for determining rotational offset between first and second gravity measurement devices deployed on a downhole tool is disclosed. The method includes positioning the tool in a previously surveyed section of a borehole that provides a historical survey including at least three previously surveyed azimuthal reference points and utilizing the gravity measurement devices to determine local azimuths at three or more sites in the previously surveyed section of the borehole. The method further includes comparing local azimuths with the historical survey and determining a rotational offset between the measurement devices that gives a best fit between local azimuths and the historical survey. A system adapted to execute the disclosed method and a computer system including computer-readable logic configured to instruct a processor to execute the disclosed method are also provided.

Abstract: A reservoir simulator first estimates rock displacement parameters (u, v, and w) representing rock movement in the x, y, and z directions. When the rock displacement parameters (u, v, w) are determined, “&egr;x,y,z” (the ‘x,y,z elongation strains’) and “&ggr;xy,yz,zx” (the ‘shear strains’) are determined since “&egr;x,y,z” and “&ggr;xy,yz,zx” are function of “u”, “v”, and “w”. When “&egr;x,y,z” and “&ggr;xy,yz,zx” are determined, “&sgr;x,y,z” (the ‘elastic normal rock stress in x,y,z directions’) and “&tgr;xy,yz,zx” (the ‘elastic shear stress’) are determined since “&sgr;x,y,z” and “&tgr;xy,yz,xz” are a function of “&egr;x,y,z” and “&ggr;xy,yz,zx”.

Abstract: A method and system is described for estimating stress characteristics from seismic data. The method includes receiving seismic data acquired over a region, receiving properties of rock at a location within the region, and estimating one or more stress characteristics for a sub-region by combining the seismic data and the rock properties using a relationship between the stress characteristics in the sub-region and elastic stiffness and/or sonic velocity in the sub-region. The relationship is based on a non-linear elasticity theory.

Abstract: Systems and methods for ultrasonically inspecting pipe, the pipe having a longitudinal axis, the methods in certain aspects including compressing with a compressing force an elastomeric element between an ultrasonic probe of an ultrasonic pipe inspection system and a pipe to be inspected thereby forcing the elastomeric element generally radially against the pipe, and the compressing force in the general direction of the longitudinal axis of the pipe or at an angle thereto; and, in certain aspects, the systems and methods including placing a coupling between the elastomeric element and the pipe, wherein the elastomeric element surrounds the pipe, wherein the elastomeric element is a packing element, and/or wherein the packing element is a packing element of a stripper packer system and the compressive force is applied by ram(s) or piston(s); and, in certain aspects, a system for ultrasonically inspecting pipe, the system with a housing, a packer element in the housing, the packer element having an opening thro

Abstract: The invention relates to a method of obtaining a developed two-dimensional image of the wall of a borehole. The method comprises the steps consisting in: measuring a primary physical magnitude in said borehole as a function both of depth and of azimuth; measuring a secondary physical magnitude in said borehole as a function of depth; establishing a relationship (ƒ) between said primary physical magnitude and said secondary physical magnitude; and deducing from said relationship values for said secondary physical magnitude as a function both of depth and of azimuth, which method makes it possible to reconstruct a two-dimensional image developed over the wall of a borehole concerning a secondary physical magnitude which is measured in said borehole as a function of depth only. The invention is particularly applicable to density imaging.

Abstract: The present invention includes a well system having a sensor; a controller for converting the sensor output, a signal conducting mass, a magnetostrictive actuator for inducing an acoustic wave the signal conducting mass, a reaction mass being greater than the signal conducting mass, an acoustic wave receiver up-hole, and a processor for processing a signal from the acoustic wave receiver and for delivering the processed signal to an output device.

Abstract: The present invention relates to a method whereby two well locations are employed to find a distribution of points where additional well locations can be found. The distribution of points form an arc defined as a trap slice. This distribution is determined in accordance with the equation An=Ae&thgr; cot &agr; wherein cot &agr; is a constant value determined on the basis of geometric data complied from existing well locations.

Abstract: A method for determining the liquefaction tendency of a water saturated soil is provided in which a driven or self boring probe with a plurality of expanding and contracting bladders imposes a cyclic shear stress reversal on a body of soil in situ, and from the measurement of pore water pressure, the liquefaction potential of the soil can be quantified. A pore water pressure increase during cyclic shear stress reversals indicates a contractive soil which has the potential to liquefy. The method can also quantify the potential of electro-osmosis in preventing soil liquefaction, by energizing a group of at least three electrodes by a d-c power source during the potential onset of liquefaction, and measure the reduction in pore water pressure during subsequent repeated shear stress reversals imposed on the soil by the device.

Abstract: The present invention provides a method for analysing a well completion system, wherein the method includes receiving data representative of physical characteristics of the completion system and calculating a first change in length of a tube string resulting from a helical buckling effect. The method further includes calculating a second change in length of the tube string resulting from a ballooning effect and calculating a third change in length of the tube string resulting from a slackoff force effect. Upon completion of the calculating steps, the method may output predetermined results therefrom.

Abstract: A method and a device for detecting and localizing unwanted matter, e.g., cement deposits, internally in a drill string. A sleeve-shaped indicator body is dropped down through the drill string while the same occupies an operative position. Then, the indicator body lands either in a seat at the lower end of the drill string, or the indicator body becomes stuck within a pipe section at a higher level in the drill string. The drill string overlying the position of the indicator body may be considered free of deposits formed on the pipe section walls thereof, and these pipe sections thus may be re-used without any further examination or cleaning. If stuck at a higher level, the indicator body is subsequently localized at the surface through examination in context of disassembling the drill string. The indicator body also may comprise an indicator element that provides a detection signal or sign for its detection and localizing on the surface.

Abstract: A borehole probe and related method and apparatus that enables information related to the depth of the probe to be determined and utilized by the probe to perform tasks. The probe, comparing its sense of depth and other sensed physical and temporal information to pre-defined procedural and conditional constraints, causes a physical action to be performed, or signals another device, or signals the surface. Generally, the probe uses sensed benchmarks within the borehole that have an associated depth as a depth framework. Within the distances between the benchmarks, the probe uses inertial or other distance measuring devices to measure distance from the benchmarks. With accurate and constant knowledge of its own depth, the probe can perform tasks autonomously and at the correct depth.

Abstract: Test equipment is deployed from a floating vessel or the like, the test equipment comprising testing apparatus for determining geotechnical, geophysical, geochemical, geological characteristics, and soil penetrator which forms an exploratory hole. The testing apparatus also includes at least one sensor or sampler. The test equipment being deployed by coiled tubing or the like, the one end of the coiled tubing being attached to the vessel. The test equipment is of sufficient weight to keep itself and the coiled tubing above it substantially vertical. The test equipment is also kept correctly orientated by a structure resting substantially on the seabed. A heave compensatior, such as one or more winching lines at a constant load tension which are attached to and support the coiled tubing. A casing can be attached to the test equipment and introduced to the exploratory hole by the soil penetrator. Such test equipment can be deployed at two separate locations simultaneously from the same vessel.

Abstract: The present invention provides a method for analysing a well completion system, wherein the method includes receiving data representative of physical characteristics of the completion system and calculating a first change in length of a tube string resulting from a helical buckling effect. The method further includes calculating a second change in length of the tube string resulting from a ballooning effect and calculating a third change in length of the tube string resulting from a slackoff force effect. Upon completion of the calculating steps, the method may output predetermined results therefrom.

Abstract: A tubing conveyed casing collar locator system that detects the casing collars in a wellbore and acoustically transmits the information through the tubing to the surface where it is detected and processed in a surface processor. The system comprises a downhole tool which comprises downhole sensors, a signal processor with memory, a drive circuit, a battery pack, and a signal generator. The surface system comprises a surface processor, depth system, and acoustic signal transmitter/receiver. The downhole tool detects casing collars as the tool is moved through the collar and acoustically transmits the data or stores the data in downhole memory according to programmed instructions. In one embodiment, the tool compares sensor signals from production elements, such as valves, to stored sensor signatures to uniquely identify the downhole element. In one embodiment, the downhole tool changes operating modes in response to surface command.

Abstract: A method and an apparatus are disclosed for the measurement of the aridity, temperature, flow rate, total pressure, still pressure, and kinetic pressure of steam at a downhole location within a well through which wet steam is flowing. The apparatus comprises a series of fiber optic sensors that are mounted on sections of a shell assembly. The apparatus is lowered into a well to different downhole locations, and measures the multiple parameters of steam at different locations and heights. The data can be stored on board for subsequent analysis at the surface when the apparatus is retrieved from the well. The apparatus is very reliable, accurate, and of long-life in harsh environments.

Abstract: The present invention provides an apparatus and method for minimizing movement of a drill string during MWD with vibration-sensitive instruments comprising conveying a drill string into a borehole with a sensor mounted on the drill string for sensing a parameter of interest of a formation. A clocked controller is disposed on the drill string for controlling timing of the sensor; and a second clocked controller is disposed at a surface location. During drilling operations, the clocked controllers are synchronized such that the surface controller is performing certain tasks in timed sequence with the sensor even though the surface controller is not connected to the sensor.

Abstract: A system for pressure testing the seals and fittings associated with at least one communication line passing through a well tool mandrel, each communication line housed within a communication line conduit defined through the well tool and sealingly engaged to each end of its corresponding communication line conduit by way of a fitting and the fittings also sealingly engaged to the communication line conduit. The system generally comprises a testing conduit, a testing passageway system, and a testing plug. The testing conduit is defined in the well tool mandrel. The testing passageway system is defined in the well tool mandrel and provides fluid communication between the testing conduit and the fittings and seals associated with each of the communication line conduits. The testing plug provides fluid communication between a pressure testing source and the testing passageway system.

Abstract: The present invention provides a method for analysing a well completion system, wherein the method includes receiving data representative of physical characteristics of the completion system and calculating a first change in length of a tube string resulting from a helical buckling effect. The method further includes calculating a second change in length of the tube string resulting from a ballooning effect and calculating a third change in length of the tube string resulting from a slackoff force effect. Upon completion of the calculating steps, the method may output predetermined results therefrom.

Abstract: An apparatus and method for monitoring and reporting downhole bit failure. Sensors are located on a sub assembly (which is separate from the drill bit itself but located above it on the drill string). Strain measurements are taken from the sensors to detect changes in induced bending and axial stresses which are related to a roller cone bearing failure. As a cone begins to fail, the average share of the total load on the bit that the failing cone can support changes, which causes a change in the bending strain induced by the eccentric loading of the cone.

Abstract: The present invention provides an apparatus and method for minimizing movement of a drill string during MWD with vibration-sensitive instruments comprising conveying a drill string into a borehole with a sensor mounted on the drill string for sensing a parameter of interest of a formation. A clocked controller is disposed on the drill string for controlling timing of the sensor; and a second clocked controller is disposed at a surface location. During drilling operations, the clocked controllers are synchronized such that the surface controller is performing certain tasks in timed sequence with the sensor even though the surface controller is not connected to the sensor.

Abstract: An instrument and method for surveying the static fluid column of a cased oil well and measuring the volume of oil and brine in the fluid column is disclosed. The instrument uses the inherent differences in specific gravity between water, oil and brine to provide a more simple, convenient, portable and cost effective means for surveying oil columns in cased oil wells. The instrument includes a probe, and a modified fishing rig used to lower and raise the probe into the oil well. The fishing rig includes a handled rod, a reel with a numeric line counter, and length of fused braided fishing line. The numeric line counter visually indicates the length of line expelled from the reel's spool. The probe includes a tubular casing, which is filled with ordinary tap water. The probe is constructed and filled with water so that it has a specific gravity greater than oil and less than brine (approximately 1.0 g/cc).

Abstract: The invention relates to an apparatus for manipulating in the height and in particular setting down of a load. The apparatus comprises a suspension on a lifting device, which suspension comprises a drive, with which drive the load can be manipulated in the height; a weighing device with which the weight of the load can be determined; a memory connected to the weighing device for storing an initial weight of the load; and comparing means for comparing an actual weight with the initial weight stored in the memory for the purpose of selective energizing of the drive in response to the comparison.

Abstract: A method for determining unknown stress parameters in earth formation measures velocities in four sonic transmissions modes (compression, fast shear, slow shear and Stoneley) at a series of depths. Relationships between measured velocities and other measured values, two independent linear constants, and three nonlinear constants associated with equations of motion for pre-stressed isotropic materials are expressed in a set of four or five velocity difference equations derived from non-linear continuum mechanics. The velocity difference equations are solved using inversion for useful stress parameters, including maximum horizontal stress, minimum horizontal stress, pore pressure, and change in pore pressure over time.

Abstract: The present invention provides a method for determining magnetometer errors during wellbore survey operations. It is capable of determining errors on up to three axes, with or without the use of an external reference measurement of the local magnetic field, and is capable of providing an accurate result using data from a minimum number of surveys. A model is used to correct the observed data and the corrected data are transformed from the tool coordinate system to a different coordinate system referenced to the earth. The difference between the corrected transformed data and reference data in the earth coordinate system is minimized to determine the model parameters. The present invention also provides a method for determining residual uncertainty in the measurements and for quality control of the measurements.

Abstract: An apparatus for sending signals downhole during drilling operations uses a main pump to pump mud from a mud pit at a substantially constant flow rate. The bulk of the pumped mud goes downhole to maintain adequate circulation for the drill bit. A bypass pipe is provided with a shut-off valve that is controlled by an electronic controller. By pulsing the opening and closing of the shut-off valve, the volumetric flow downhole is pulsed. The pulse amplitude and duration can be controlled. These pulses in the flow rate are detected by a suitable downhole device such as a flow rate measurement device, a pressure detector or a turbine. The initial “wake-up” pulse is made long enough so that the detection device downhole is always able to detect it. Subsequent to this wake-up pulse, adjustments are made to the pulse duration, in steps of about 2 seconds, for the smallest pulse period that is detectable downhole.