Subterranean formation characterization using microelectromechanical system (mems) devices

Abstract

Systems and methods for formation characterization in a subterranean formation are disclosed. A set of microelectromechanical system (MEMS) devices may be disposed in a circulating fluid. Each MEMS device in the set may have a machine-scannable designator. A MEMS scanner may be configured to scan the designator of a MEMS device in response to circulation of the circulating fluid in a wellbore surrounded by the formation. A MEMS analysis subsystem communicatively coupled with the MEMS scanner may store the designator of each MEMS device in the set, detect a subset of MEMS devices by receiving the designators of MEMS devices from the MEMS scanner, and determine a characteristic of the formation based on the subset of MEMS devices.

What is claimed is: 
     
         1 . An apparatus comprising:
 a microelectromechanical system (MEMS) device with an associated multi-unit designator; and   a capsule encapsulating the MEMS device and adapted for use in subterranean operations;   wherein a first unit of the multi-unit designator is machine-scannable from the MEMS device while the MEMS device is encapsulated within the capsule.   
     
     
         2 . The apparatus of  claim 1 , wherein the MEMS device is passive. 
     
     
         3 . The apparatus of  claim 1 , wherein the multi-unit designator includes a serial number. 
     
     
         4 . The apparatus of  claim 3 , wherein each unit of the multi-unit designator is an individual digit or character of the serial number. 
     
     
         5 . The apparatus of  claim 1 , wherein the capsule includes a reactive part that reacts to a characteristic of a subterranean formation and a nonreactive part that does not react to the characteristic. 
     
     
         6 . The apparatus of  claim 5 , wherein the multi-unit designator is magnetically encoded along a length of the MEMS device, the magnetically encoded length of the MEMS device being partially encapsulated by the reactive part and partially encapsulated by the nonreactive part. 
     
     
         7 . The apparatus of  claim 5 , wherein the reactive part of the capsule reacts to the characteristic by degrading to expose a portion of the MEMS device, the exposed portion being associated with the reactive part such that the exposed portion is no longer encapsulated by the capsule in response to the degrading of the reactive part. 
     
     
         8 . The apparatus of  claim 7 , wherein a second unit of the multi-unit designator associated with the exposed portion of the MEMS device is not machine-scannable from the MEMS device due to the reaction of the reactive part of the capsule to the characteristic. 
     
     
         9 . The apparatus of  claim 7 , wherein at least part of the exposed portion of the MEMS device detaches from the MEMS device in response to no longer being encapsulated. 
     
     
         10 . The apparatus of  claim 5 , wherein the characteristic of the subterranean formation is at least one of a temperature and a nuclear radiation. 
     
     
         11 . (canceled) 
     
     
         12 . The MEMS device of  claim 5 , wherein the characteristic of the subterranean formation is associated with chemical properties of matter within the formation. 
     
     
         13 . The apparatus of  claim 1 , wherein the capsule emulates a physical attribute associated with at least one of a fluid disposed downhole during the subterranean operations and a solid disposed within the fluid. 
     
     
         14 . The apparatus of  claim 13 , wherein the solid disposed within the fluid is a drill cutting. 
     
     
         15 . The apparatus of  claim 13 , wherein the solid disposed within the fluid is a lost-circulation material (LCM) solid. 
     
     
         16 . The apparatus of  claim 13 , wherein the physical attribute is at least one of a size, a shape, and an aspect ratio associated with the solid. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . The apparatus of  claim 13 , wherein the physical attribute is a density associated with the fluid. 
     
     
         20 . The apparatus of  claim 19 , wherein the capsule is constructed of a material selected to emulate the density associated with the fluid, the material being selected from a group consisting of: ceramic, polymer, metal, and glass. 
     
     
         21 . A method comprising:
 circulating a volume of circulating fluid through a wellbore surrounded by a subterranean formation, the circulating fluid comprising a microelectromechanical system (MEMS) device encapsulated by a capsule adapted for use in subterranean operations;   identifying the MEMS device in response to circulating the volume of circulating fluid; and   determining a characteristic of the subterranean formation based on identifying the MEMS device.   
     
     
         22 . The method of  claim 21 , wherein the MEMS device is identified by a MEMS scanner located at a position on a well surface above the subterranean formation where the volume of circulating fluid emerges from the wellbore after circulating through the wellbore. 
     
     
         23 . The method of  claim 21 , wherein the MEMS device is identified by a MEMS scanner located along the wellbore while the MEMS device is carried by the volume of circulating fluid circulating through the wellbore. 
     
     
         24 . The method of  claim 23 , wherein the MEMS scanner is located along a drill string within the wellbore. 
     
     
         25 . The method of  claim 21 , further comprising:
 identifying the MEMS device prior to circulating the volume of circulating fluid within the wellbore; and   determining that the MEMS device reacted to a characteristic of the subterranean formation based on a change detected between identifying the MEMS device prior to circulating and identifying the MEMS device in response to circulating.   
     
     
         26 . The method of  claim 25 , wherein:
 the MEMS device is associated with a multi-unit designator having units that are machine-scannable from the MEMS device while the MEMS device is encapsulated within the capsule; and   the change detected is that one or more units of the multi-unit designator are machine-scannable at the identifying of the MEMS device prior to circulating but are not machine-scannable at the identifying of the MEMS device in response to circulating.   
     
     
         27 . The method of  claim 25 , wherein the characteristic of the subterranean formation relates to at least one of a temperature of the subterranean formation, nuclear radiation within the subterranean formation, and chemical properties of matter within the formation. 
     
     
         28 . The method of  claim 21 , wherein the capsule is adapted for use in subterranean operations by emulating a physical attribute associated with a solid disposed within the circulating fluid. 
     
     
         29 . The method of  claim 28 , wherein the solid is a loss circulation material (LCM) solid.