| PATHFINDER ENERGY SERVICES, INC. Patent applications |
| Patent application number | Title | Published |
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| 20100154531 | Caliper Logging Using Circumferentially Spaced and/or Angled Transducer Elements - A downhole tool includes circumferentially spaced and/or angled transducer elements. In one embodiment a standoff sensor has at least three piezoelectric transducer elements, at least a first element of which is configured to both transmit and receive ultrasonic energy. At least second and third of the elements are configured to receive ultrasonic energy transmitted by the first element in pitch catch mode. An electronic controller is configured to calculate a standoff distance from the ultrasonic waveforms received at the first, the second, and the third piezoelectric transducer elements. The controller may further be configured to estimate the eccentricity of a measurement tool in the borehole. Exemplary embodiments of the invention may improve borehole coverage and data quality and reliability in LWD caliper logging. In particular, the invention may advantageously reduce or even eliminate blind spots when logging eccentric bore holes. | 06-24-2010 |
| 20100126770 | Non-Azimuthal and Azimuthal Formation Evaluation Measurement in a Slowly Rotating Housing - A steering tool configured for making azimuthal and non-azimuthal formation evaluation measurements is disclosed. In one embodiment a rotary steerable tool includes at least one formation evaluation sensor deployed in the steering tool housing. The steering tool may include, for example, first and second circumferentially opposed formation evaluation sensors or first, second, and third formation evaluation sensors, each of which is radially offset and circumferentially aligned with a corresponding one of the steering tool blades. The invention further includes methods for geosteering in which a rotation rate of the steering tool housing in the borehole (and therefore the rotation rate of the formation evaluation sensors) is controlled. Steering decisions may be made utilizing the formation evaluation measurements and/or derived borehole images. | 05-27-2010 |
| 20090192711 | Data compression method for use in downhole applications - Borehole image data is compressed and transmitted to the surface one pixilated trace at a time. The compression methodology typically includes transform, quantization, and entropy encoding steps. The invention advantageously provides for sufficient data compression to enable conventional telemetry techniques (e.g., mud pulse telemetry) to be utilized for transmitting borehole images to the surface. By compressing and transmitting sensor data trace by trace the invention also tends to significantly reduce latency. | 07-30-2009 |
| 20090190850 | Data compression transforms for use in downhole applications - Borehole image data is compressed and transmitted to the surface one or more pixilated traces at a time. The compression methodology typically includes transform, quantization, and entropy encoding steps. The invention advantageously provides an efficient fixed point Karhünen-Loève like transform for compressing sensor data. A significant reduction in latency is achieved as compared to the prior art. | 07-30-2009 |
| 20090173504 | Transverse magnetization of casing string tubulars - A method and apparatus for imparting a transverse magnetization to a wellbore tubular is disclosed. In certain exemplary embodiments, tubulars are magnetized to include at least one flux reversal (e.g., at the center of the tubular) at which the direction of the transverse field changes (i.e., from pointing radially inward to pointing radially outward). A plurality of such magnetized wellbore tubulars may be coupled together and lowered into a target well to form a magnetized section of a casing string. Exemplary embodiments of the invention may be utilized to impart a strong, highly uniform magnetic field about a string of wellbore tubulars, thereby providing for improved passive ranging and wellbore twinning. | 07-09-2009 |
| 20090090554 | CLOSED-LOOP PHYSICAL CALIPER MEASUREMENTS AND DIRECTIONAL DRILLING METHOD - Aspects of this invention include a downhole tool and method for making a physical caliper measurement of a subterranean borehole. The tool is configured to make the physical borehole caliper measurement only when the measured pressure in each of three or more outwardly extendable blades is greater than a predetermined threshold pressure. Blade positions are measured and the borehole caliper calculated only when the pressure in each of the blades exceeds the threshold. Exemplary embodiments of the invention enable physical caliper measurements to be made with increased accuracy with each of the blades making firm contact with the borehole wall. Methods in accordance with the invention are especially well suited for use in directional drilling applications in that they tend to enable accurate caliper measurements to be made without repositioning the steering tool in the borehole. | 04-09-2009 |
| 20090058675 | Non-contact capacitive datalink for a downhole assembly - Aspects of this invention include a downhole assembly having a non-contact, capacitive coupling including first and second transceivers deployed in corresponding first and second downhole tool members. The capacitive coupling is disposed to transfer electrical signals between the first and second transceivers. In one exemplary embodiment, the capacitive coupling is configured to transfer data and power between a substantially non-rotating tool member and a rotating tool member, for example, the shaft and blade housing in a steering tool. Exemplary embodiments of this invention provide a non-contact, high-speed data communication channel between first and second members of a downhole assembly. Moreover, exemplary embodiments of the invention also provide for simultaneous non-contact transmission of electrical power between the first and second tool members. | 03-05-2009 |
| 20090030616 | Probablistic imaging with azimuthally sensitive MWD/LWD sensors - A method for forming a borehole image of an azimuthally sensitive borehole or formation parameter is disclosed. Such a borehole image may be formed, for example, by processing logging sensor data with a predetermined sensor response function (also referred to herein as a probability density function) to acquire probabilistically distributed sensor data. The sensor data may be distributed in either one-dimension (azimuthal) or two-dimensions (azimuthal and axial). Certain embodiments of this invention may be advantageously utilized in LWD imaging applications and provide for superior image resolution and noise rejection as compared to prior art binning techniques. Exemplary embodiments of the invention also advantageously conserve logging sensor data such that integration of the distributed data over the entire circumference of the tool provides a non-azimuthally sensitive logging measurement. | 01-29-2009 |
| 20080294344 | Angular position sensor for a downhole tool - Aspects of this invention include a downhole tool having an angular position sensor disposed to measure the relative angular position between first and second members disposed to rotate about a common axis. A plurality of magnetic field sensors are deployed about the second member and disposed to measure magnetic flux emanating from first and second magnets deployed on the first member. A controller is programmed to determine the relative angular position based on magnetic measurements made by the magnetic field sensors. In a one exemplary embodiment, a downhole steering tool includes first and second magnets circumferentially spaced on the shaft and a plurality of magnetic field sensors deployed about the housing. | 11-27-2008 |
| 20080294343 | Gravity zaimuth measurement at a non-rotting housing - Aspects of this invention include methods for surveying a subterranean borehole. In one exemplary aspect, a change in borehole azimuth between first and second longitudinally spaced gravity measurement sensors may be determined directly from gravity measurements made by the sensors and a measured angular position between the sensors. The gravity measurement sensors are typically disposed to rotate freely with respect to one another about a longitudinal axis of the borehole. Gravity MWD measurements in accordance with the present invention may be advantageously made without imposing any relative rotational constraints on first and second gravity sensor sets. The present invention also advantageously provides for downhole processing of the change in azimuth between the first and second gravity sensor sets. As such, Gravity MWD measurements in accordance with this invention may be advantageously utilized in closed-loop steering control methods. | 11-27-2008 |
| 20080284440 | Logging while drilling tool for obtaining azimuthally sensitive formation resistivity measurements - An apparatus for making azimuthally sensitive resistivity measurements of a subterranean formation is disclosed. The apparatus includes a magnetically permeably ring deployed about an electrically conductive tool body. An AC voltage supply is coupled to the tool body on opposing sides of the magnetically permeable ring, with at least one connecting conductor crossing outside the ring. Exemplary embodiments of this invention may further include one or more current sensing electrodes deployed in and electrically isolated from an outer surface of a blade deployed on the tool body and may be utilized to make azimuthally resolved formation resistivity measurements | 11-20-2008 |
| 20080275648 | Method of optimizing a well path during drilling - A method for determining a list of survey points for a drilling well includes a feedback loop in which one or more measured parameters are compared with computed or derived parameters. The computed parameters are typically obtained from other/additional measurements. For example, in one exemplary embodiment of the invention, a magnetic least distance vector determined via magnetic ranging is compared with a geometric least distance vector computed from conventional borehole surveying measurements. Estimates of the drilling well azimuth and/or inclination may be adjusted to yield a good agreement between the magnetic and geometric least distance vectors. Exemplary embodiments of the present invention advantageously provide for a substantially real-time determination of a definitive well path for a drilling well as well as a substantially real-time relative placement of the drilling well with respect to a target well. | 11-06-2008 |
