DOWNHOLE GAUGE TELEMETRY SYSTEM AND METHOD FOR A MULTILATERAL WELL

Abstract

A downhole gauge telemetry system for a multilateral well includes a first wireless transceiver located in a primary borehole of the multilateral well, a second wireless transceiver located in a lateral borehole of the multilateral well, a wireless connection between the first wireless transceiver and the second wireless transceiver through which the first and second wireless transceivers exchange data, and a surface transceiver communicatively coupled to the first wireless transceiver.

Description

BACKGROUND OF THE INVENTION

The invention relates generally to multilateral well operations. More particularly, the invention relates to a system and method for monitoring reservoir/borehole conditions in a multilateral well.

Multilateral wells, also known as multi-branch wells, have lateral boreholes that tie back to a primary wellbore. Production through the primary wellbore can be significantly increased by bringing the lateral boreholes into close proximity with several target reservoirs. To maximize production, sensors/gauges can be installed in the lateral boreholes and used to monitor reservoir/borehole conditions, such as pressure, temperature, and flow rate in the tubing and annulus. The output of the sensors/gauges can be monitored in real-time and used to control inflow from the lateral boreholes such that production is optimized. To enable monitoring of reservoir/borehole conditions, powering of the sensors/gauges and communication between the sensors/gauges and the surface must be reliable. Making wire connections between the surface and lateral boreholes can be cumbersome or impossible. For example, it would be difficult to run the long wires needed to make signal transmission links between the surface and each of the sensors/gauges in the lateral boreholes. Wireless technology may alleviate some of the concerns with wired transmission links.

U.S. Pat. No. 6,899,178 issued to Tubel describes a wireless tool that can be deployed in one or more branches of a multilateral well. The wireless tool transmits acoustic data to a data acquisition transceiver at the surface via production tubing. The data acquisition transceiver is connected to a data processor, which may be equipped with Supervisory Control and Data Acquisition (SCADA) software. The wireless tool includes a wireless tool transceiver for wireless transmission of data to the surface transceiver. The wireless tool transceiver includes transformer, piezoelectric crystal or other acoustic generator, and acoustic transmitter. The wireless tool includes a data acquisition module, which is connected to the wireless tool transceiver. The data acquisition module obtains data from sensors/gauges at predetermined locations in the well. The wireless tool includes a replaceable power source, such as batteries. The replaceable power source may be augmented or replaced by downhole power generation.

SUMMARY OF THE INVENTION

In one aspect, the invention relates to a downhole gauge telemetry system for a multilateral well which comprises a first wireless transceiver located in a primary borehole of the multilateral well, a second wireless transceiver located in a lateral borehole of the multilateral well, a wireless connection between the first wireless transceiver and the second wireless transceiver through which the first and second wireless transceivers exchange data, and a surface transceiver communicatively coupled to the first wireless transceiver.

In another aspect, the invention relates to a method of transmitting data in a multilateral well extending from a surface comprises deploying a first wireless transceiver in a primary borehole of the multilateral well, deploying a second wireless transceiver in a lateral borehole of the multilateral well, establishing a wireless connection between the first wireless transceiver and the second wireless transceiver, wirelessly transmitting data between the first wireless transceiver and the second wireless transceiver over the wireless connection, establishing data communications between the first wireless transceiver and a surface transceiver, and transmitting data between the first wireless transceiver and the surface transceiver.

Other features and advantages of the invention will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, described below, illustrate typical embodiments of the invention and are not to be considered limiting of the scope of the invention, for the invention may admit to other equally effective embodiments. The figures are not necessarily to scale, and certain features and certain view of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness.

FIG. 1 is a block diagram of a downhole gauge telemetry system for a multilateral well.

FIG. 2 shows an implementation of the downhole gauge telemetry system of FIG. 1 in a multilateral well.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described in detail with reference to a few preferred embodiments, as illustrated in the accompanying drawings. In describing the preferred embodiments, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the invention may be practiced without some or all of these specific details. In other instances, well-known features and/or process steps have not been described in detail so as not to unnecessarily obscure the invention. In addition, like or identical reference numerals are used to identify common or similar elements.

FIG. 1 is a block diagram of a downhole gauge telemetry system 100 for a multilateral well. The telemetry system 100 includes surface transceiver (or receiver/transmitter) 102 connected to a data processing system 103, wherein the data processing system 103 retrieves data from the surface transceiver 102 and processes the data. The surface transceiver 102 communicates with and receives data from a first wireless transceiver (or receiver/transmitter) 104 in a primary wellbore of the multilateral well. Communication between the surface transceiver 102 and the first wireless transceiver 104 may be over a wired or wireless connection. The first wireless transceiver 104 in turn communicates with and receives data from a second wireless transceiver (or receiver/transmitter) 106 in a lateral borehole of the multilateral well over a wireless connection 107. The first and second wireless transceivers 104, 106 may be acoustic devices, including for example, transformer, acoustic generator, and acoustic transmitter. Acoustic signals may be generated, for example, by piezoelectric material or magneto-restrictive material. The acoustic generator typically transmits at frequencies unaffected by pump noise. The wireless connection 107 may be provided by tubing or fluid between the first and second wireless transceivers 104, 106. Communication between the first and second wireless transceivers 104, 106 may be one-way or bi-directional.

A data acquisition module 108 is located in the lateral borehole and coupled to the second wireless transceiver 106 via communications link 110. The data acquisition module 108 includes the circuitry needed to collect data and may include memory for storing data. The data acquisition module 108 may also be equipped with a rechargeable or replaceable power source. One or more sensors/gauges 112 are coupled to the data acquisition module 108 via communications link 114, which may be a wired link. The sensors/gauges 112 may monitor/measure one or more reservoir/borehole conditions or parameters. In one example, the sensors/gauges 112 are selected from pressure sensor, temperature sensor, fluid flow sensor, fluid identification sensor, resistivity sensor, cross-well acoustic sensor, cross-well seismic sensor, perforation depth sensor, fluid characteristics sensor, logging data sensor, strain gauge, and vibration sensor. In operation, the data acquisition module 108 obtains data from the sensors/gauges 112 through the communication link 114. The second wireless transceiver 106 transmits the data from the data acquisition module 108 to the first wireless transceiver 104 over the wireless connection 107. The first wireless transceiver 104 in turn transmits the data received from the second wireless transceiver 106 to the surface transceiver 102. Data may be transmitted from downhole to the surface in real-time, in a predetermined sequence, or in response to a command from the surface transceiver 102.

The telemetry system 100 includes a power generator 116 which can supply power to the sensors/gauges 112, the second wireless transceiver 106, and the data acquisition module 108. The power generator 116 can be a piezoelectric power generator, i.e., one that uses a piezoelectric stack to convert motion or vibration into electrical energy. The piezoelectric stack may convert motion of borehole fluids or vibrations within piping in the lateral borehole into electrical energy. Other power generators besides one based on piezoelectric may be used. For example, turbines or magneto-restrictive power generation may be used. The telemetry system 100 also includes a power generator 118 at the surface. The power generator 118 supplies power to the surface transceiver 102. The first wireless transceiver 104 may also be connected to the power generator 118 in order to receive power. Alternately, the first wireless transceiver 104 may be provided with a downhole power source or generator.

The physical implementation of the telemetry system 100 in a multilateral well may take various forms. FIG. 2 shows an example wherein a multilateral well 200 extends below a surface 202. The multilateral well 200 includes a primary wellbore 204 and a lateral borehole 206. The multilateral well 200 can have more than one lateral borehole, but only one is shown for the sake of simplicity. The primary wellbore 204 is shown as vertical, but it may also be deviated or horizontal. Casing 208 extends from a wellhead 210 near the surface 202 into the primary wellbore 204. The lateral borehole 206 is accessible through a window in the casing 208. Although not shown, a liner or other tubular may be installed in the lateral borehole 206, for example, to prevent the lateral borehole from collapsing. A production tubing 212 extends from the wellhead 210 down through the casing 208 and into the lateral borehole 206. The first wireless transceiver 104 and the power generator 118 can be mounted on the portion of the production tubing 212 in the primary wellbore 204, with a cable 214 running between them. The power generator 118 is linked to the surface transceiver 102. Sensors/gauges 222 may be mounted on the portion of the production tubing 212 in the primary wellbore 204 and used to monitor reservoir/borehole conditions in the primary wellbore 204. The sensors/gauges 222 may also be powered by the power generator 118.

The second wireless transceiver 104 is mounted on the portion of the production tubing 212 in the lateral borehole 206. The data acquisition module 108, power generator 116, and sensors/gauges 112 are also mounted on the portion of the production tubing 212 in the lateral borehole 206. In the arrangement shown in FIG. 2, the data acquisition module 108 is mounted adjacent to the second wireless transceiver 104 and the power generator 116 adjacent to the data acquisition module 108. These components can be contained within a single housing or multiple housings made of material suitable for use in a downhole environment. The sensors/gauges 112 are mounted further down, with cable links 216 between them and the power generator 116 and data acquisition module 108. As an example, the sensors/gauges 112 may be electromagnetic or resistivity sensors, gravity sensors, and geophones, or hydrophones. Flow controllers with drivers 218 are also mounted on the production tubing 212 to monitor inflow in the lateral borehole 206. The flow controllers 218 may also be powered by the power generator 116. Packers 220, which may be swellable elastomer packers, are also mounted on the production tubing 212 to isolate a portion of the lateral borehole 206. In this example, the production tubing 212 and/or fluid in the production tubing 212 can provide the wireless connection between the first and second wireless transceivers 104, 106. Acoustics waves may travel between the first and second wireless transceivers 104, 106 through the production tubing 212 and the fluid in the production tubing 212.

While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims

1. A downhole gauge telemetry system for a multilateral well, comprising:

a first wireless transceiver located in a primary borehole of the multilateral well;

a second wireless transceiver located in a lateral borehole of the multilateral well;

a wireless connection between the first wireless transceiver and the second wireless transceiver through which the first and second wireless transceivers exchange data; and

a surface transceiver communicatively coupled to the first wireless transceiver.

2. The downhole gauge telemetry system of claim 1, wherein the first and second wireless transceivers are acoustic wireless transceivers.

3. The downhole gauge telemetry system of claim 1, further comprising a data acquisition module communicatively coupled to the second wireless transceiver.

4. The downhole gauge telemetry system of claim 3, further comprising at least one sensor located in the lateral borehole and communicatively coupled to the data acquisition module.

5. The downhole gauge telemetry system of claim 4, wherein the sensor is selected from the group consisting of pressure sensor, temperature sensor, fluid flow sensor, fluid identification sensor, resistivity sensor, cross-well acoustic sensor, cross-well seismic sensor, perforation depth sensor, fluid characteristics sensor, logging data sensor, strain gauge, and vibration sensor.

6. The downhole gauge telemetry system of claim 1, further comprising a power generator located in the lateral borehole.

7. The downhole gauge telemetry system of claim 4, wherein the power generator is a piezoelectric power generator.

8. The downhole gauge telemetry system of claim 1, wherein the first wireless transceiver communicates with the surface transceiver over a wired connection.

9. A method of transmitting data in a multilateral well extending from a surface, comprising:

deploying a first wireless transceiver in a primary borehole of the multilateral well;

deploying a second wireless transceiver in a lateral borehole of the multilateral well;

establishing a wireless connection between the first wireless transceiver and the second wireless transceiver;

wirelessly transmitting data between the first wireless transceiver and the second wireless transceiver over the wireless connection;

establishing data communications between the first wireless transceiver and a surface transceiver; and

transmitting data between the first wireless transceiver and the surface transceiver.