Abstract: Methods and systems for enhanced capture and recovery of core samples from unconsolidated or friable formations are provided using drilling fluids that permit increased overpressures to preserve the ability to cut core samples and to strengthen the core samples obtained. Drilling fluids used during capture and recovery of core samples may comprise a solid particulate loss prevention material having a size range from about 150 microns to about 1,000 microns. The solid particulate loss prevention material prevents fracture initiation and propagation in the subterranean formation to allow the use of higher overpressures than would otherwise be possible. Thus, by circulating drilling fluid in the borehole while drilling a core sample, higher overpressures may be achieved, which have been found to be beneficial during core capture and recovery by maintaining core integrity and avoiding core loss. In this way, core sample integrity is improved, yielding more accurate representations of the subsurface.

Abstract: This invention relates to drilling a well, particularly an oil or gas well, where casing or liner will be installed to stabilize the wellbore. The present invention is intended to permit more drilling and longer lengths of casing or liner to be installed at one time. The present invention includes a combination of a smear tool and specially sized granular lost circulation material solids in the drilling mud which work together to close and seal leaking formations and fractures whether pre-existing or induced by drilling. By the natural collection of the inventive solids along with the conventional particles in the drilling mud to form a filter cake at the problem areas along the wall of the wellbore and the smear tool arranged to compress the filter cake into the problem areas, lost circulation is minimized Maintaining circulation naturally allows for longer drilling cycles and potentially fewer liner joints in the well.

Abstract: This invention relates to drilling a well, particularly an oil or gas well, where casing or liner will be installed to stabilize the wellbore. The present invention is intended to permit more drilling and longer lengths of casing or liner to be installed at one time. The present invention includes a combination of a smear tool and specially sized granular lost circulation material solids in the drilling mud which work together to close and seal leaking formations and fractures whether pre-existing or induced by drilling. By the natural collection of the inventive solids along with the conventional particles in the drilling mud to form a filter cake at the problem areas along the wall of the wellbore and the smear tool arranged to compress the filter cake into the problem areas, lost circulation is minimized. Maintaining circulation naturally allows for longer drilling cycles and potentially fewer liner joints in the well.

Abstract: Methods and systems for enhanced capture and recovery of core samples from unconsolidated or friable formations are provided using drilling fluids that permit increased overpressures to preserve the ability to cut core samples and to strengthen the core samples obtained. Drilling fluids used during capture and recovery of core samples may comprise a solid particulate loss prevention material having a size range from about 150 microns to about 1,000 microns. The solid particulate loss prevention material prevents fracture initiation and propagation in the subterranean formation to allow the use of higher overpressures than would otherwise be possible. Thus, by circulating drilling fluid in the borehole while drilling a core sample, higher overpressures may be achieved, which have been found to be beneficial during core capture and recovery by maintaining core integrity and avoiding core loss. In this way, core sample integrity is improved, yielding more accurate representations of the subsurface.

Abstract: This invention relates to drilling a well, particularly an oil or gas well, where casing or liner will be installed to stabilize the wellbore. The present invention is intended to permit more drilling and longer lengths of casing or liner to be installed at one time. The present invention includes a combination of a smear tool and specially sized granular lost circulation material solids in the drilling mud which work together to close and seal leaking formations and fractures whether pre-existing or induced by drilling. By the natural collection of the inventive solids along with the conventional particles in the drilling mud to form a filter cake at the problem areas along the wall of the wellbore and the smear tool arranged to compress the filter cake into the problem areas, lost circulation is minimized. Maintaining circulation naturally allows for longer drilling cycles and potentially fewer liner joints in the well.

Abstract: Improved methods of correcting the vertical permeability contrast of a subterranean formation to improve the sweep efficiency of waterflooding operations carried out therein wherein the subterranean formation contains at least one high permeability zone lying adjacent and in fluid communication with at least one low permeability zone are provided. In accordance with the methods, a near well bore portion of the high permeability zone is plugged and a crosslinked gel is formed at least at the boundary between the low permeability zone and the high permeability zone whereby fluid communication between the zones is reduced.

Abstract: A steam generator for burning a normally-solid fuel which produces non-combustible solid residues, including, an elongated combustion chamber, a fuel introduction means to introduce fuel adjacent the axis of the combustion chamber as a centrally-disposed stream moving in a downstream direction, a combustion-supporting gas introduction means for introducing the gas as an annular, rotating stream about the fuel stream and which, together with the fuel introduction means forms a rotating, toroidal vortex of the fuel and the combustion-supporting gas moving in a downstream direction. The combustion chamber has a volume sufficient to burn all of the fuel and, together with the fuel introduction means and the combustion-supporting gas introduction means, cause the vortex to collapse and form plug flow thereafter. Water introduction means introduces water into the flue gas at the downstream end of the combustion chamber as a plurality of peripherally-arranged jets.

Abstract: A method for generating steam by a high pressure, high intensity, or high heat release method of combustion in an elongated combustion zone having upstream and downstream ends and an intermediate location and utilizing a normally-solid fuel which produces non-combustible solid residues in which the fuel is introduced axially and a volume of air, at least equal to the stoichiometric amount, is introduced as an annular, rotating stream to produce a rotating vortex of fuel and air, such introduction and flow through the combustion zone being carried out in a manner to collapse the vortex and create plug flow at the intermediate location, burning the fuel and air to produce flue gas at a heat release rate of at least 7 MM Btu/hr, abruptly terminating combustion by the introduction of water, vaporizing the water to produce a mixture of flue gas and steam, and separating solid residues therefrom.

Abstract: NO.sub.x emissions are reduced in the combustion of fuels by carrying out the combustion in at least four serially connected combustion zones, including at least three fuel-rich zones followed by a fuel-lean zone. In accordance with another aspect of the present invention, SO.sub.x emissions are reduced in the burning of a normally solid fuel, containing significant amounts of SO.sub.x precursors, by adding a sulfur scavenger to the fuel and thereafter burning the fuel in at least four serially connected combustion zones, including at least three fuel-rich zones followed by a last fuel-lean zone, and carrying out the combustion of the fuel in at least four combustion zones.

Abstract: NO.sub.x emissions are reduced in the combustion of a fuel, containing significant amounts of NO.sub.x precursors, by carrying out the combustion in at least three, serially connected combustion zones in open communication with one another, including at least two fuel-rich zones and a last fuel-lean zone and in the presence of a combustion catalyst added to the fuel adjacent the upstream end of the first of the fuel-rich zones. SO.sub.x emissions are also reduced when burning a fuel, containing significant amounts of SO.sub.x precursors, by additionally adding a sulfur scavenger to the fuel adjacent the upstream end of the first fuel-rich zone.