Abstract:
Multiple sensors in a wellbore can be utilized in a high density sweep analysis. In particular, annular pressures, recorded by the multiple sensors as the sweep is circulated, can be utilized to analyze the performance of a high density sweep. The high density sweep analysis can be used to create a prediction of the impact of circulating a high density sweep. The high density sweep analysis can calculate the position of the high density sweep in the well during the circulation by utilizing the multiple sensors and derive information about the presence of solids in the well, their likely location and whether or not the wellbore is clean prior to tripping out of the well.
Abstract:
The invention provides a pump comprising a pump inlet, a pump outlet, at least two threaded rotors and a pressure controlled valve, the pressure controlled valve being capable of controlling re-circulation of fluid from the pump outlet to the pump inlet. The pressure controlled valve can be a control valve. The invention also provides a multiple stage pump assembly comprising at least two pumps arranged in series, wherein at least one of the pumps is the aforementioned pump.
Abstract:
A low frequency sound source has a radiating piston (3) of the order of a few meters across backed by a gas spring (13, 15) containing a fixed mass of gas. The gas pressure in the spring is kept at levels for which the natural frequency of the piston (3) loaded by the fluid (41) lies in the seismic band and may be as low as 0.5 Hz. The piston (3) is given an initial displacement and begins to oscillate. Its oscillations are sustained by an actuator (27, 29) whose drive signal is derived from the velocity of the piston (5) via a velocity or displacement sensor. The sound source is caused to perform a frequency sweep by gradually compressing the gas in the gas spring (13, 15) so that the spring becomes stiffer both because of the rising pressure and because of the reducing length of the gas spring spaces (13, 15). This double effect allows large changes in stiffness to be produced and hence allows the source to operate over at least three octaves of frequency.
Abstract:
Process for converting synthesis gas to hydrocarbons in a slurry reactor in the presence of a Fischer-Tropsch catalyst comprising cobalt and zinc oxide. The process is carried out by a) activating the Fischer-Tropsch catalyst with a reducing gas consisting of hydrogen and an inert gas at a temperature between 330 and 400° C., and b) contacting the activated Fischer-Tropsch catalyst from step a) with synthesis gas in the slurry reactor in order to convert the synthesis gas into hydrocarbons.
Abstract:
A subsea pressure relief valve includes a water-filled nozzle fluidly connected to a hydrocarbon distribution manifold. A valve body is connected to the distribution manifold, with an outlet of the nozzle coincident with an interior water-filled chamber of the valve body. A first seal element is removably seated against the nozzle outlet and an arm is hinged to the body and configured to apply a force along a seal axis and bias the first seal element into sealing engagement with the nozzle outlet until hydrocarbon pressure exceeds a sealing pressure of the applied force and unseats the first seal element from the nozzle outlet such that excess hydrocarbons exit through an outlet of the valve body. A weight is disposed on the arm at a distance from the seal axis.
Abstract:
Load bearing assembly for suspending a load from a wellhead assembly, having a connector for suspending jointed production tubing therefrom and a fluid-to-air connector seals around an electrical conductor extending therethrough. The assembly has a jointed production tubing section with a first connector for connecting the tubing to the wellhead assembly connector. The assembly has a second connector for connecting the jointed production tubing section to a load bearing part of an electrical conduction section of the assembly. The load bearing part suspends the weight of the electrical conduction section and a load in a well from the second connector. The electrical conduction section includes an electrical conductor part for supplying electrical power to the load. The electrical conductor part is connected to an electrical cable which extends outside and along the jointed production tubing section away from the second connector and towards the well head in use.
Abstract:
Physical models of wells are used to determine rate and phase composition for fluid produced from or injected into the wells on a near real time and continuous basis. The method can be used to alert operators or others of conditions in a well or field to permit more immediate response. The method can be more tolerant of sensor faults, sensor drift, anomalous data or other occurrences which could otherwise lead to incorrect output. More than one model can be used to permit a hierarchy of calculation such that the rate and phase determination is more tolerant of anomalous data. The calculated rate and phase values from one or more wells can be reconciled against facility data.
Abstract:
Hydrocarbons are recovered from subterranean formations by waterflooding. The method comprises passing an aqueous displacement fluid via an injection well through a porous and permeable sandstone formation to release oil and recovering said released oil from a production well spaced from said injection well, wherein (a) the sandstone formation comprises at least one mineral having a negative zeta potential under the formation conditions; (b) oil and connate water are present in the pores of the formation; and (c) the fraction of the divalent cation content of the said aqueous displacement fluid to the divalent cation content of said connate water is less than 1.
Abstract:
Methods of jarring include communicating between a surface command device and jars in a drill string, the drill string composed of spaced apart jars positioned in a corresponding plurality of wired and/or wireless pipe sections. The methods include selectively controlling charging, firing, amount of force, and/or direction of force of the jars using digitally-controlled surface command devices. One method includes firing a sub-set or all of the jars in a controlled manner and determining depth of a stuck drill string section through analysis of behavior or performance of the fired jars. Other methods include subsequently firing one or more of the jars again below the stuck drill string section. Other methods include selectively firing, using digital signals from the surface command device, jars sequenced in time so that their forces meet in a constructive or destructive manner at a preselected point in the drill string.
Abstract:
The present invention provides a process for the production of olefins wherein a synthetic naphtha is passed to a steam cracker. The synthetic naphtha is derived from the fractionation of a Fischer-Tropsch product stream. The Fischer-Tropsch product stream may be separated into a lighter fraction and a heavy fraction and the heavy fraction may be hydrotreated prior to fractionation. Optionally the synthetic naphtha may be hydrogenated to produce a saturated synthetic naphtha which can then be subsequently passed to the steam cracker.