Application of RFID technology in liner cementing

RFID is a method of communication that uses radio frequency electromagnetic fields. Information is Stored within the RFID tag and is transmitted to the reader when the tag comes into proximity with the reader. There are two types of tags: active tags that contain their own energy source, and passive tags that are charged when in proximity to a reader. Passive tags are generally used in drilling and completion Tools, as shown in Figure 1. The tag contains a transponder with a unique identification code and reader instructions and an antenna that receives signals from the reader.

The reader contains a receiving antenna and a power supply that generates an electromagnetic field, as shown in Figure 2. When the tag is in close proximity, the magnetic field generated by the antenna charges the tag and causes the tag to transmit the stored instructions. The receiving antenna can be programmed to respond only to specific tag identification codes; tags that do not contain these identification codes are automatically ignored when approaching the reader.

In the Valhall oilfield in Norway, the Tor and Hod reservoirs are affected by the overlying strata and the formation pressure suddenly decreases. Using traditional drilling techniques will usually cause drilling stuck or drilling fluid loss, which is usually solved by liner drilling or casing drilling techniques. Cementing in this type of formation also faces greater challenges. Conventional cementing methods will lead to mud loss. An RFID cementing system was designed for the Tor and Hod reservoirs. The cementing tools include RFID perforated shorts, casing joints that can rotate the liner during the cementing process, and expandable annular casing metal packers. During construction, the liner is lowered into the lost circulation layer, the cementing short-circuit is installed above the low-pressure zone, cement slurry is pumped to the floating hoop, and the packer isolates the low-pressure zone. RFID is used to open the perforated nipple above the low-pressure zone to pump in cement slurry to avoid leakage of cement slurry in the low-pressure zone. This process does not cause wellbore pressure fluctuations and successfully solves the problem of cementing loss in Tor and Hod reservoirs.

Radio frequency identification cementing technology can avoid pressure disturbances and maintain the integrity of the well wall in some oil fields with complex conditions. It can be controlled remotely or mechanically under emergency conditions. It can be widely used in narrow pressure window cementing. Well operations in progress.