Study and Implement of the Large Amount Data Divided Time Transmission System Utilizing Microchip-Storage-Ball Release While Drilling

Abstract

The more downhole information measured by LWD tools, the more measurement data they produces. The conventional LWD tools can hardly transfer all the large amount of data of LWD tools to the surface, which greatly limits its advantages in while-drilling production. If retrieved after drilling, certain LWD tools would lose their advantages entirely in while-drilling production. This paper proposes a novel method that employs the basic concept of a "flash drive" downloading and exchanging data among computers. A system is developed to achieve data transmission in a time-division manner using releasable microchip storage. The system includes a plurality of microchip storages, a plurality of sealed chambers each for containing a microchip storage, a release power device, and a circuit. The release signal is sent by time setting or pressure signal triggering. In drilling, the data measured by the LWD tools can be downloaded into the microchip storage. A release signal could be sent on time, or the release signal can be triggered and sent by the pump pressure pulse, when the LWD data is needed. Upon receiving the release signal, the circuit sends a release command to control the power device to release the microchip storage from the drill collar into the drilling fluid in the annular. The microchip storage can be carried to the surface by drilling fluid and can be recovered. The data in the microchip storage can then be retrieved. In this system, there are four contacts on the microchip storage to connect with the circuit, through which power supply and data connection are established. The data access to the LWD data complies with the RS485 data protocol. The system adopts a push technology. The data capacity of single microchip storage is 1 Mbit, and the size of which is 12mm (D)×12.5mm (H). One drill collar system can carry up to 24 microchip storages. Thus it makes a single collar system have a large data storage capacity. It can improve the efficiency of data transmission.