An oil or gas production method forms a wellbore in a rock formation, wherein the wellbore including a lateral portion, and the method introduces a plurality of perforation diverters into the wellbore, wherein each perforation diverter in the plurality of diverters includes circuitry for determining a pressure proximate the perforation diverter, and the method measures a respective pressure proximate each perforation diverter and within the lateral portion.

A method for predicting a pressure window for drilling a borehole in a formation includes: obtaining a pore pressure related data value of the formation using a data acquisition tool; predicting pore pressure uncertainty from the pore pressure related data value of the formation using a processor; estimating uncertainty of a pressure window for drilling fluid using the predicted pore pressure uncertainty using a processor; and applying the estimated uncertainty to the pressure window to provide a modified pressure window using a processor.

A method for predicting a pressure window for drilling a borehole in a formation includes: obtaining a pore pressure related data value of the formation using a data acquisition tool; predicting pore pressure uncertainty from the pore pressure related data value of the formation using a processor; estimating uncertainty of a pressure window for drilling fluid using the predicted pore pressure uncertainty using a processor; and applying the estimated uncertainty to the pressure window to provide a modified pressure window using a processor.

A method for determining a location of a proppant in a subterranean formation includes obtaining a first set of data in a wellbore using a downhole tool. The proppant is pumped into the wellbore after the first set of data is obtained. The proppant is pumped while or after the subterranean formation is fractured. A second set of data is obtained in the wellbore using the downhole tool after the proppant is pumped into the wellbore. The first set of data and the second set of data include a gravitational field measurement. The first and second sets of data are compared, and in response to the comparison, the location of the proppant in the subterranean formation is determined.

A system that is positionable in a wellbore in a subterranean formation can include a first transceiver that is positionable external to a casing string in the wellbore. The first transceiver can wirelessly transmit data via a signal within a frequency band that is selected based on a fluid property of a fluid in the wellbore and a property of the subterranean formation. The system can also include a second transceiver that is positionable externally

A system that is positionable in a wellbore in a subterranean formation can include a first transceiver that is positionable external to a casing string in the wellbore. The first transceiver can wirelessly transmit data via a signal within a frequency band that is selected based on a fluid property of a fluid in the wellbore and a property of the subterranean formation. The system can also include a second transceiver that is positionable externally

A system that is positionable in a wellbore can include a chain of transceivers that are positionable external to a casing string. Each transceiver in the chain of transceivers can be operable to transmit a wireless signal using a separate frequency guard band that is assigned to that transceiver and to receive wireless signals using another frequency guard band assigned to a prior transceiver in the chain of transceivers.

A communication system that is positionable in a wellbore can include a first transceiver for coupling externally to a casing string. The first transceiver can be for wirelessly transmitting data by generating and modulating a surface wave that propagates along an interface surface. The surface wave can include an electromagnetic wave that has a magnetic field or an electric field that is at an acute angle to a direction of propagation of the surface wave. The communication system can also include a second transceiver for coupling to the casing string and for wirelessly receiving the surface wave and detecting the data.

Embodiments of a downhole drilling assembly generally include a rotatable lower drilling assembly, a rotatable upper drilling assembly, and a drill bit, wherein the upper drilling assembly contains a mud motor adapted for clockwise rotation of its stator and counter-clockwise rotation of its rotor, whereby the lower drilling assembly is rotatable in the opposite direction of the upper drilling assembly or maintainable in a non-rotating state. The apparatus further includes sensors adapted to continuously measure physical properties and/or drilling parameters and a mechanism for continuously transmitting information relating thereto to the surface.

Embodiments of a method for operating a downhole drilling assembly generally include continuously measuring physical properties and/or drilling parameters proximate the drill bit, continuously transmitting information relating thereto to the surface, and controlling rotation of a lower drilling assembly in a non-rotating state or in the opposite direction of an upper drilling assembly by varying drill string rotation.

Embodiments of a downhole drilling assembly generally include a rotatable lower drilling assembly, a rotatable upper drilling assembly, and a drill bit, wherein the upper drilling assembly contains a mud motor adapted for clockwise rotation of its stator and counter-clockwise rotation of its rotor, whereby the lower drilling assembly is rotatable in the opposite direction of the upper drilling assembly or maintainable in a non-rotating state. The apparatus further includes sensors adapted to continuously measure physical properties and/or drilling parameters and a mechanism for continuously transmitting information relating thereto to the surface.

Embodiments of a method for operating a downhole drilling assembly generally include continuously measuring physical properties and/or drilling parameters proximate the drill bit, continuously transmitting information relating thereto to the surface, and controlling rotation of a lower drilling assembly in a non-rotating state or in the opposite direction of an upper drilling assembly by varying drill string rotation.