often are electrically connected to sensors and assist in relaying sensor information to the surface of the well it is conceivable that the sensors associated with a particular electronics module may even be packaged within the electronics module finally the electronics module is often closely associated with and may actually contain a modem for receiving sending and relaying communications from and to the surface of the well signals that are received from the surface by the electronics module are often used to effect changes within downhole controllable devices such as valves signals sent or relayed to the surface by the electronics module generally contain information about downhole physical conditions supplied by the sensors the terms u201c first end u201d and u201c second end u201d as used herein are defined generally to call out a side or portion of a piping structure which may or may not encompass the most proximate locations as well as intermediate locations along a called out side or portion of the piping structure similarly in accordance with conventional terminology of oilfield practice the descriptors u201c upper u201d u201c lower u201d u201c uphole u201d and u201c downhole u201d refer to distance along hole depth from the surface which in deviated wells may or may not accord with absolute vertical placement measured with reference to the ground surface referring to fig2 in the drawings a petroleum well according to the present invention is illustrated the.