A method of wellbore analysis using TM01 and TE01 modes of radar waveforms can include transmitting, at a first time, a radar waveform from a wellhead into a tubing disposed in a wellbore positioned in a reservoir. The radar waveform is either a TM01 mode or a TE01 mode waveform. The tubing includes a fluid, and the surface of the wellbore includes the wellhead. At a second time, a reflected waveform generated by reflecting the transmitted radar waveform on a fluid surface of the fluid is received at the wellhead. A fluid level of the fluid is determined based on the time difference between the first time and the second time, and on a transmission speed of the radar waveform from the wellhead to the fluid surface. The fluid level is a distance between the wellhead and the fluid surface of the fluid.

A method of estimating a depth of a hydrocarbon-water contact of a hydrocarbon reservoir in a structure. The method may include the steps of analysing one or more samples obtained from the structure to generate a relationship relating resistivity to hydrocarbon-water contact depth, obtaining a resistivity measurement of the hydrocarbon reservoir, and estimating the hydrocarbon-water contact depth from the relationship relating resistivity to hydrocarbon-water contact depth and the resistivity measurement of the hydrocarbon reservoir.

A method of estimating a depth of a hydrocarbon-water contact of a hydrocarbon reservoir in a structure. The method may include the steps of analysing one or more samples obtained from the structure to generate a relationship relating resistivity to hydrocarbon-water contact depth, obtaining a resistivity measurement of the hydrocarbon reservoir, and estimating the hydrocarbon-water contact depth from the relationship relating resistivity to hydrocarbon-water contact depth and the resistivity measurement of the hydrocarbon reservoir.

A system for monitoring an annular fluid level may include a floating element disposed on a surface of a drilling fluid within an annulus of the well, during mud cap drilling operations. The system may also include an antenna disposed above the floating element. The antenna may be configured to transmit a first signal to the floating element, and to receive a second signal from the floating element in response to the first signal. The system may also include a processor configured to determine a time value that measures a time between a transmittal, by the antenna, of the first signal and a receipt, by the antenna, of the second signal. The processor may also determine a state of a drilling fluid level within the annulus based on the time value, and update a drilling program for the well based on the state of the drilling fluid level.

A system for monitoring an annular fluid level may include a floating element disposed on a surface of a drilling fluid within an annulus of the well, during mud cap drilling operations. The system may also include an antenna disposed above the floating element. The antenna may be configured to transmit a first signal to the floating element, and to receive a second signal from the floating element in response to the first signal. The system may also include a processor configured to determine a time value that measures a time between a transmittal, by the antenna, of the first signal and a receipt, by the antenna, of the second signal. The processor may also determine a state of a drilling fluid level within the annulus based on the time value, and update a drilling program for the well based on the state of the drilling fluid level.

A system can determine a temperature profile based on a prior production temperature profile and a reference start point pressure for a well. The system can virtually divide the well into a plurality of sections including uphill sections and downhill sections. The system can determine a gas-oil interface depth for each section of the plurality of sections from a water-oil ratio and a gas-oil ratio based on the temperature profile and the reference start point pressure. The system can determine an oil-water interface depth for each section of the plurality of sections from the gas-oil ratio and the water-oil ratio based on the temperature profile and the reference start point pressure.

A system can determine a temperature profile based on a prior production temperature profile and a reference start point pressure for a well. The system can virtually divide the well into a plurality of sections including uphill sections and downhill sections. The system can determine a gas-oil interface depth for each section of the plurality of sections from a water-oil ratio and a gas-oil ratio based on the temperature profile and the reference start point pressure. The system can determine an oil-water interface depth for each section of the plurality of sections from the gas-oil ratio and the water-oil ratio based on the temperature profile and the reference start point pressure.

A fluid level sensor system is disclosed for sensing a fluid level in a well. The system has a main body and an inlet housing coupled to the main body. The inlet housing has an internal chamber in communication with an ambient environment within the well. A bellows within the main body communicates with the internal chamber of the inlet housing. A movable element is responsive to movement of the bellows. A sensor detects when the movable element moves from a first position, indicating a first fluid level in the well, to a second position indicating a second fluid level within the well. An indicator is operably associated with the movable element and moves into a position to be viewable when the sensing element is moved to the second position, to provide a visual indication that the second fluid level has been reached.

A fluid level sensor system is disclosed for sensing a fluid level in a well. The system has a main body and an inlet housing coupled to the main body. The inlet housing has an internal chamber in communication with an ambient environment within the well. A bellows within the main body communicates with the internal chamber of the inlet housing. A movable element is responsive to movement of the bellows. A sensor detects when the movable element moves from a first position, indicating a first fluid level in the well, to a second position indicating a second fluid level within the well. An indicator is operably associated with the movable element and moves into a position to be viewable when the sensing element is moved to the second position, to provide a visual indication that the second fluid level has been reached.

An extraction well system is disclosed that allows for isolation of electrical cables from underground mine atmosphere. The extraction well system provides for a well casing that extends downwardly proximate to an existing mine cavity and an extension casing that extends downwardly below the mine roof. In one embodiment the extension casing is external to the well casing and is attached to the well casing mechanically such as with a dual thread reducer. The extension runs from above the mine roof to below the mine floor and is perforated in the area of the mine cavity to allow liquid to drain into the bottom of the extension well. In a second embodiment, the extension casing is interior to the well casing and is attached for example by an internal liner hanger. In this embodiment, the extension casing runs from above the mine roof to below the desired minimum liquid level and it is the well casing that extends downwardly in the extension well and which is perforated to allow liquids to flow into the well.