COMMUNICATING MEASUREMENT DATA FROM A WELL

• US 20080236837A1
• Filed: 11/26/2007
• Published: 10/02/2008
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Lovell, John R., Chouzenoux, Christian, Champagnon, Christophe, Chaudhary, Ashish
• Granted Patent: US 7,921,916 B2
• Time in Patent Office: Days
• US Class Current: 166/336
• CPC Class Codes: E21B 47/12 Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
• CPC Class Codes: H03M 7/30 Compression speech analysis-synthesis for redundancy reduction G10L19/00; for image communication H04N; Expansion; Suppression of unnecessary data, e.g. redundancy reduction

Abstract

To communicate measurement data from a well, data corresponding to measurement data collected by multiple sensors in a well is transformed downhole and passed to an intermediate communications device, which device in turn passes a subset of that data to a destination communications device. The destination communications device applies a second transformation to the data received from the intermediate communications device. The first and second transformations are designed such that meaningful data can be recovered at the destination communications device even though only a subset of the original transformed data has been received.

Claims

1. A method for communicating measurement data from a well, comprising:

applying a downhole transformation to measurement data collected by sensors in the well;

passing the transformed measurement data through an intermediate communications device that applies a lossy compression algorithm; and

transforming data received from the intermediate communications device so as to produce meaningful data at a destination communications device.

2. The method of claim 1, wherein applying the downhole transformation comprises converting the measurement data collected by the sensors into blocks, where at least one of the blocks contains portions of the measurement data that are expected to vary more than portions of the measurement data contained in at least another of the blocks.

3. The method of claim 2, wherein converting the measurement data into blocks comprises converting the measurement data into a first block that contains a first group of bits from the measurement data of the sensors, and another block that contains a second group of bits from the measurement data of the sensors.

4. The method of claim 1, wherein applying the downhole transformation comprises encrypting the measurement data from the sensors, and wherein transforming the data received from the intermediate communications device comprises decrypting the data received from the intermediate communications device.

5. The method of claim 1, wherein the intermediate communications device applies the lossy compression algorithm by transmitting only a subset of the transformed measurement data.

6. The method of claim 1, wherein passing the transformed measurement data through the intermediate communications device comprises passing the transformed measurement data through a subsea communications module.

7. The method of claim 1, wherein applying the lossy telemetry algorithm comprises forwarding only those portions of the transformed measurement data that have changed by at least a predetermined threshold amount.

8. The method of claim 6, further comprising a destination communications device receiving the data from the subsea communications module, wherein the destination communications device comprises a surface communications device.

9. The method of claim 1, further comprising:

receiving, by the intermediate communications device, additional transformed measurement data corresponding to measurement data collected by sensors in a second well; and

checking, by the intermediate communications device, for portions of the additional transformed measurement data to forward to the destination communications device according to whether the portions of the additional transformed measurement data have changed by at least a threshold amount.

10. The method of claim 1, further comprising receiving the measurement data using wireless communications components in the well.

11. The method of claim 1, further comprising receiving measurement data from the sensors that are arranged as an array of sensors disposed along a reservoir section of the well.

12. The method of claim 11, wherein the downhole transformation of measurement data is applied to the array of sensors.

13. The method of claim 12, wherein each packet of the transformed measurement data contains a component of sensor information from all of the sensors of the array.

14. A system comprising:

sensors for deployment in a well;

a first module to receive measurement data from the sensors and to transform first portions of the measurement data from the sensors into a first block and to transform second portions of the measurement data from the sensors into a second block; and

an intermediate communications device to receive the first and second blocks from the first module and to apply a lossy compression algorithm on the blocks.

15. The system of claim 14, wherein the intermediate communications device comprises a subsea communications module.

16. The system of claim 14, wherein the lossy compression algorithm selects one of the blocks to not send.

17. The system of claim 14, wherein the transformation applied by the first module further transforms third portions of the measurement data from the sensors into a third block, wherein the intermediate communications device receives the first, second, and third blocks from the first module and applies the lossy compression algorithm on the received blocks, wherein the lossy compression algorithm selects at least one of the first, second, and third blocks to not send to the destination communications device.

18. The system of claim 14, wherein the first block has data that is expected to vary at a slower rate than data in the second block.

19. The system of claim 16, wherein the selected one of the first and second blocks that is not sent to the destination communications device is the block where data has varied from a previous version of the block by less than a threshold amount.

20. The system of claim 14, further comprising additional sensors for deployment in a second well;

and

a second module to receive measurement data from the additional sensors in the second well and to transform first portions of the measurement data from the additional sensors into a third block, and to transform second portions of the measurement data from the additional sensors into a fourth block, and

wherein the intermediate communications device is to receive the third and fourth blocks from the second module and to apply the lossy compression algorithm on the third and fourth blocks.

21. The system of claim 14, further comprising an inductive coupler to communicate the measurement data from the sensors to the first module.

22. The system of claim 21, further comprising a downhole control module for deployment in the well, wherein the downhole control module is connected between the inductive coupler and the first module.

23. The system of claim 14, further comprising a wireless telemetry stage to communicate the measurement data from the sensors to the first module.