|Publication number||US4083604 A|
|Application number||US 05/741,820|
|Publication date||Apr 11, 1978|
|Filing date||Nov 15, 1976|
|Priority date||Nov 15, 1976|
|Publication number||05741820, 741820, US 4083604 A, US 4083604A, US-A-4083604, US4083604 A, US4083604A|
|Inventors||Jack R. Bohn, Durk J. Pearson|
|Original Assignee||Trw Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (9), Referenced by (127), Classifications (14)|
|External Links: USPTO, USPTO Assignment, Espacenet|
In-situ processes are governed by the subsurface structure, the process fluid flows, and their interactions. A major problem with in-situ processes has been to establish intimate contact between the process fluids and the deposits, and to establish sufficient porosity or fractures to permit process fluid circulation. It is important that the fracture of the deposit is sufficiently fine so that the process proceeds at a sufficient rate with a high enough efficiency to be economic, but not too fine because fluid flow pressure drop in a packed bed increases by an order of magnitude for a bed particle size reduction of 2, thereby increasing fluid pump or compressor and piping capital and operating costs by a similar amount. There are numerous fracture techniques which are currently in use, among which are explosions, hydrofracture, leaching a soluble phase, electrofracture, abrasive cutting, and acids, to name a few.
Where these fracture techniques were applied to oil shale deposits, explosives were the most commonly used. In this potentially dangerous approach, underground tunnels were carved into the oil shale deposits in a predetermined pattern for the purpose of blasting and rubblizing the deposit. In performing the blasting process, care was required to leave sufficient support so that the entire overburden of the deposit was not collapsed into the tunnel voids. Considerable difficulty was experienced in rubblizing the oil shale deposit to produce rubble of the appropriate size which would support a reasonably uniform flame front for the retorting of the hydrocarbon values in the shale. If the rubble was not reasonably uniform and of proper size, a substantially uniform flame front was not maintained, and process and product gases mixed and reacted which contributed to the quenching of the desired retort flame front and reduced product recovery. Thus, much time and consideration was given to the blasting patterns which were used to rubblize the oil shale deposits, and even then the fracturing patterns produced were frequently by chance.
The present invention relates to an in-place method for the recovery of mineral values from subsurface deposits. More particularly, the present process relates to a method for producing a fracturing pattern in subsurface oil shale deposits.
By properly injecting heat into the subsurface deposits, full control of fracturing can be achieved, i.e. from promotion to inhibition. Where a fracturing pattern is sought for a particular subsurface deposit, a core sample of the deposit is first extracted. The core sample is subjected to a particular heating schedule to induce the proper thermal gradients into the core sample so as to promote measured and controlled strain and fracturing. In general, more extreme thermal gradients will lead to more extensive fracturing and a smaller average particle size. When the thermomechanical characterization of the core sample has been completed, the heating schedule computed from the thermomechanical characterization of the core is applied to the subsurface deposit to produce the desired fracturing pattern.
Non-steady state thermal stresses arise as a result of transient temperature gradients in a body and the corresponding differential thermal expansion which cannot be accommodated by geometrically compatible displacement within the body. These stresses continually adjust themselves in such a way that the internal forces in the body are self-equilibrating and the displacements are compatible. If, in the process, either the stresses or the strains reach some critical value, failure may occur.
In general, either fracture or excessive deformation may be taken as the critical failure mode. The expression "thermal shock" has been defined by materials investigators as catastrophic brittle fracture which occurs as a result of high tensile stresses which are generated at the cooler side of transiently heated bodies. These same tensile forces might instead produce excessive deformation in a body if the material were strong enough to resist fracture, or if it were ductile rather than brittle. Even if the deformation were not excessive during a single heating and cooling cycle, multiple cycling can lead to an accumulated deformation which eventually will become excessive.
One mode of failure for in-situ processing involves both plastic flow and fracture near the heated surface of the body. Regions of checking or cracking have been noted near the heated surface where compressive plastic flow has occurred during heating. It has recently been discovered that the reversal of stress at the hot surface, from compressive to tensile, and the reversal of plastic flow from compressive to tensile, occurs not when the body cools but earlier in the cycle, i.e. as soon as the temperature gradient begins to disappear. This will happen even if the overall temperature of the body is still increasing, as might be the case during sustained heating. Thus, the heated surface material might be put into tension, which would be multiaxial tension in most cases, while it is still very hot to the point of approaching melting, and ductile fracture or hot tearing would very easily take place. Cracking of this nature could also lead to loss of material at the hot surface which might be mistaken for compressive spallation in any post-test evaluation.
In order to apply the theoretical considerations previously set forth, a core sample from the deposit which is to be extracted is subjected to a heating schedule to determine the thermomechanical characteristics of the deposit material. Geneally, more extreme thermal gradients will lead to more extensive fracture and a smaller average particle size, while larger average particle sizes will result from more gradual thermal gradients.
These thermomechanical fractures will occur in three principle modes. In one mode, the hot retort wall (or surface of a boulder or rock) is put into compression compared to the cooler surrounding strata, and failure occurs in compression by buckling or spallation. In another mode, the hot inside wall is put into compression compared to the cooler surrounding strata which then fail in tension. In the third mode, the hot inside wall is put into compression and undergoes plastic flow during the period when the thermal gradient is relative high. As the heat spreads outward and the thermal gradient becomes less steep, a more distant material heats up, expands, and causes a tensile hot tearing failure at the hot inner wall.
It should be noted that with the proper temperature versus time cycles that it is possible to preferentially comminute large boulders, blocks, and the cavity walls while exercising a lesser size reduction effect on smaller pieces of rubble. This is because the surface area to volume ratio of the former is smaller than that of the latter. Because of this, the former rocks can be subjected to larger thermal gradients for longer periods of time than is the case with smaller rubble which heats up in its interior relatively rapidly. As a result, the proper temperature versus time cycles can yield a more uniform rubble bed with fewer hugh blocks which are wasted resource because of inefficient extraction, and fewer fines which greatly decrease bed permeability, hence greatly increase the process system's capital and operating costs.
Thermomechanical control of fracture can be applied to oil shale deposits to effect proper rubblization of the deposits so that mineral and hydrocarbon value extraction may be optimized. One particular area which has rich oil shale deposits as well as rich mineral deposits, is the Piceance Creek Basin in northwestern Colorado. This area contains recoverable oil shale, nahcolite, and dawsonite which lends itself to an integrated in-place process that first extracts nahcolite and is followed by shale oil recovery, alumina recovery, and finally residual fuel values recovery. In order for as much as possible of the mineral and hydrocarbon values to be recovered, the process must be conducted in a sequence of specific steps. In the first step, a core hole is drilled into the shale deposit, and the core is extracted. The core sample is then subjected to controlled heating combined with strain measurements and computation to determine the thermomechanical characteristics of the minerals and hydrocarbon values in the deposit. When the thermomechanical characteristics of a particular portion of the deposit has been determined, an injection well and producer wells are sunk into the deposit. These may be coaxial, i.e. in the same hole, such as a reamed out bore hole. Steam is injected into the shale deposit to fracture the deposit according to the fracturing parameters of temperature versus time determined by the core sample tests and calculations and to remove the nahcolite mineral by leaching. The nahcolite leach, together with the thermomechanical fracturing, will produce a rubblization of the shale deposit which will render the deposit permeable and porous.
Upon completion of the nahcolite removal, the resulting gas-tight chamber may be tested to determine if sufficient rubblization has occurred. If further rubblization is required, the chamber may be exposed to further thermal cycling so as to produce the desired particle size which will result from the further fracture of the rubble. By continual monitoring of the rubble in the chamber, close control may be exercised over the chamber conditions.
After creating porosity in the formation by leaching the water soluble nahcolite from the shale zone, and by inducing thermomechanical fracture, the chamber is pumped dry and in-situ retorting of the oil shale can be accomplished by the circulation of a hot, pressurized, non-oxidizing fluid, such as heated low molecular weight hydrocarbon gas, steam, heated retort off-gas, comprising H2, CO, N2, CO2, and mixtures thereof from the injection well through the permeable shale bed and out the producing well. During the retorting process, heat is transferred from the hot fluid to the shale, causing the kerogen and dawsonite to decompose according to the following idealized reactions:
kerogen → bitumen → oil + gas + residue (1)
2NaAl(OH)2 CO3 → Na2 CO3 + Al2 O3 + 2H2 O + CO2 (2)
naAl(OH)2 CO3 → NaAlO2 + CO2 + H2 O(3)
neither reaction (2) nor (3) represents the sole mechanism for dawsonite decomposition, although it is known that reaction (3) is the predominant one at the higher temperatures and reaction (2) is almost non-existent at temperatures above 650° F.
The in-situ retorting process should be carried out in the temperature range of 660° to 930° F, and preferably between 800° and 850° F. These temperature ranges will permit rapid completion of the oil evolution from the raw shale, and the decomposition of dawsonite to chi-alumina which occurs about 660° F. In addition, co-occurring with the dawsonite is the nordstrandite which forms difficult to leach gamma-alumina at temperatures above 930° F. The retorting of oil shale at temperatures in the range of 800° to 850° F leads to a quality shale oil product with a typical pour point about 25° F, and API gravity of about 28° and a nitrogen content of less than 0.8 weight percent according to Hill and Dougan in The Characteristics of a Low-Temperature In-Situ Shale Oil, Quarterly of the Colorado School of Mines, Volume 62, No. 3, July 1967. In contrast, the shale oil from high temperature retorting can have a pour point of as high as 90° F and API gravity of about 20° and a nitrogen content of approximately 4 weight percent. Thus, the shale oil product from the low-temperature process may be readily transported to refineries by a pipeline, and on-site upgrading becomes optional.
If the recovery of hydrocarbon values are not as great as estimated, thermal cycling may be performed using the retorting gas as the medium. Constant monitoring of the permeability of the shale bed should be conducted to note changes in pressure versus flow relation. Excessive comminuation with its accompanying high pressure drop should be avoided.
Pressures for the in-situ retorting process will depend upon the permeability of the shale bed, the height and density of the overburden, and the heat capacity and circulation rate of the hot fluid. A higher pressure minimizes the volume of recirculating hot fluid required, but this could lead to a considerable drop in the yield of shale oil according to Bae, Some Effects of Pressure in Oil Shale Retorting, Society Petroleum Engineers Journal, No. 9, Page 243.
Oil vapor from the decomposition of kerogen is cooled by the formation ahead of the retorting front and condenses and drains into a pocket from which it can be pumped along with some water from dawsonite decomposition. The off-gas produced by the kerogen in the retorting process includes four components comprising the hot fluid used for retorting, the hydrocarbon gas from the kerogen decomposition, hydrocarbon oil vapors, and the carbon dioxide and water vapor from the dawsonite decomposition. If the gas from kerogen decomposition is used as the heat carrier for retorting, the resulting off-gas will have a medium heating value after the removal of the water and CO2.
In the retorting of each shale member, the recirculating fluid has only to be externally heated during the first part of the retorting period. After approximately half of the shale bed chamber has been retorted, cooler fluid can be injected into the formation and heated by the hot, retorted shale bed. Thus, waste heat can be recovered from the first half of the retorted shale bed and used for retorting of the remaining portion of the shale.
After the retorting step has been completed, alumina which was formed from dawsonite and nordstrandite can be extracted. This light base extractable alumina which was created when the oil shale was retorted at moderate temperatures, was formed by dawsonite when it was heated to 350° C according to the following reaction as reported by Smith and Young in Dawsonite: Its Geochemistry, Thermal Behavior, and Extraction from Green River Oil Shale, paper presented at the Eighth Oil Symposium, Colorado School of Mines, Golden, Colo., April 17-18, 1975:
2NaAl(OH)2 CO3 → Na2 CO3 + Al2 O3 + 2H2 O + CO2 (2)
this alumina which includes values from nordstrandite, can be extracted from the retorted oil shale by solution of 1 N sodium carbonate and a nonionic or suitable surfactant such as:
polyoxyalkylene oxide block copolymers
ethoxylated aliphatic alcohols
alkyl benzene sulfonates
alkanol amide sulfates
The solution equation is represented as:
Al2 O3 + 2CO3 = + H2 O → 2HCO3 - + 2AlO2 - (4)
as this leach liquor fills the cavity, it creates a water drive to mobilize unrecovered shale oil and float it to the top of the cavity. This oil and pregnant solution can then be removed to the surface.
The alumina recovery facility first transports the recovered liquids to a liquid/liquid separator. The oil then goes to the oil recovery plant, and the aqueous solution is then sent to a clarifier to remove shale fines. Subsequently the liquid is passed through a series of carbon dioxide bubblers where the solution pH is progressively lowered from 11 to 9 causing the alumina to precipitate from solution. The solid is then washed, filtered, and calcined to produce alumina.
Even with good yields from the primary and secondary recovery processes, residual fuel value will remain in the retort bed in the form of unmobilized oil and carbonaceous residue. Although this residue has little direct commercial value, it may yield sufficient fuel value to supply heat for the production of steam for the leach phase, the heating of retorting gas for hot gas retorting in another chamber, and substantial amounts of CO, H2 and liquid and vapor hydrocarbons. In view of this, a tertiary recovery step is effected which comprises removing water of the previous stem from the retort chamber and instituting a flame front to combust the residue. After combustion of the residue has begun, water vapor is injected down the well hole. The water vapor reacts with the residue to hydrogenate the remaining unsaturated hydrocarbon values so that polymerization does not occur. By preventing polymerization of the hydrocarbon values during pyrolysis, the residue is fluid and readily flows in advance of the flame front. In addition, the presence of steam facilitates fossile fuel energy mobilization by means of the water gas reaction:
H2 O + C → CO + H2
when all practical hydrocarbon and mineral values have been removed from the retort chamber, the chamber is backfilled with water, solutions, or slurries to prevent subsidence of the soil and collapse of the underground structures. Aqueous solutions suitable for this purpose may comprise some of the excess minerals which were removed in some of the previous recovery processes. Thus, if more sodium bicarbonate is being removed than can be disposed of economically, the solutions or slurries of these materials may be pumped back into the ground for storage and later removal. Subsidence of the soil must be controlled to prevent process interruption and to minimize environmental damage. The vertical component of the stress field is governed by unit weight of the rock and the vertical depth in the opening. The reaction to this stress and size of the opening which can be tolerated without collapse will be governed by the strength of the rock immediately above the opening. The chamber roof may be thermomechanically strengthened by processing which introduces residual stresses in the roof which oppose the gravitational stresses.
To minimize soil subsidence, extraction operation must leave pillars of undisturbed shale to support the overburden This technique is commonly used in room and pillar mining. Thus, to reduce the possibility of earth subsidence which follows an initial roof collapse that causes stress and disruption of strata all the way to the earth's surface, back-filling with pressurized water or aqueous solutions or slurries should be considered.
After the chamber has been back-filled, the pipe may be plugged to seal the chamber. When the next level of mining has been determined, the pipe is perforated at that level and the process is repeated.
Each step of the process is integrated and interdependent upon obtaining the inputs of process fuels, chemicals, or working fluids which are supplied as outputs by some other process stage. Thus, it would be impractical to pump large quantities of a basic surfactant into a borehole to recover alumina values unless the chamber had been leached and retorted previously. Likewise, recovery of hydrocarbon values from the oil shale would be difficult and expensive unless the chamber was first made porous and permeable by the nahcolite leach. Therefore, in order to carry out the process in a logical and economic manner, the process steps must be followed in the sequence set forth previously.
Although there may be numerous modifications and alternatives apparent to those skilled in the art, it is intended that the minor deviations from the spirit of the invention be included within the scope of the appended claims, and that these claims recite the only limitations to be applied to the present invention.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2661066 *||Jun 26, 1948||Dec 1, 1953||Pure Oil Co||Increasing permeability of sands in oil, gas, and injection wells by forming solids in the strata|
|US3465826 *||Oct 19, 1967||Sep 9, 1969||Gulf Research Development Co||High-temperature water injection|
|US3502372 *||Oct 23, 1968||Mar 24, 1970||Shell Oil Co||Process of recovering oil and dawsonite from oil shale|
|US3539221 *||Nov 17, 1967||Nov 10, 1970||Kettaneh Anthony||Treatment of solid materials|
|US3753594 *||Sep 24, 1970||Aug 21, 1973||Shell Oil Co||Method of producing hydrocarbons from an oil shale formation containing halite|
|US3759328 *||May 11, 1972||Sep 18, 1973||Shell Oil Co||Laterally expanding oil shale permeabilization|
|US3759574 *||Sep 24, 1970||Sep 18, 1973||Shell Oil Co||Method of producing hydrocarbons from an oil shale formation|
|US3779601 *||Sep 24, 1970||Dec 18, 1973||Shell Oil Co||Method of producing hydrocarbons from an oil shale formation containing nahcolite|
|US3957306 *||Jun 12, 1975||May 18, 1976||Shell Oil Company||Explosive-aided oil shale cavity formation|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4744245 *||Aug 12, 1986||May 17, 1988||Atlantic Richfield Company||Acoustic measurements in rock formations for determining fracture orientation|
|US7644765||Oct 19, 2007||Jan 12, 2010||Shell Oil Company||Heating tar sands formations while controlling pressure|
|US7673681||Oct 19, 2007||Mar 9, 2010||Shell Oil Company||Treating tar sands formations with karsted zones|
|US7673786||Apr 20, 2007||Mar 9, 2010||Shell Oil Company||Welding shield for coupling heaters|
|US7677310||Oct 19, 2007||Mar 16, 2010||Shell Oil Company||Creating and maintaining a gas cap in tar sands formations|
|US7677314||Oct 19, 2007||Mar 16, 2010||Shell Oil Company||Method of condensing vaporized water in situ to treat tar sands formations|
|US7681647||Mar 23, 2010||Shell Oil Company||Method of producing drive fluid in situ in tar sands formations|
|US7683296||Mar 23, 2010||Shell Oil Company||Adjusting alloy compositions for selected properties in temperature limited heaters|
|US7703513||Oct 19, 2007||Apr 27, 2010||Shell Oil Company||Wax barrier for use with in situ processes for treating formations|
|US7717171||Oct 19, 2007||May 18, 2010||Shell Oil Company||Moving hydrocarbons through portions of tar sands formations with a fluid|
|US7730945||Oct 19, 2007||Jun 8, 2010||Shell Oil Company||Using geothermal energy to heat a portion of a formation for an in situ heat treatment process|
|US7730946||Oct 19, 2007||Jun 8, 2010||Shell Oil Company||Treating tar sands formations with dolomite|
|US7730947||Oct 19, 2007||Jun 8, 2010||Shell Oil Company||Creating fluid injectivity in tar sands formations|
|US7785427||Apr 20, 2007||Aug 31, 2010||Shell Oil Company||High strength alloys|
|US7793722||Apr 20, 2007||Sep 14, 2010||Shell Oil Company||Non-ferromagnetic overburden casing|
|US7798220||Apr 18, 2008||Sep 21, 2010||Shell Oil Company||In situ heat treatment of a tar sands formation after drive process treatment|
|US7798221||Sep 21, 2010||Shell Oil Company||In situ recovery from a hydrocarbon containing formation|
|US7831133||Apr 21, 2006||Nov 9, 2010||Shell Oil Company||Insulated conductor temperature limited heater for subsurface heating coupled in a three-phase WYE configuration|
|US7831134||Apr 21, 2006||Nov 9, 2010||Shell Oil Company||Grouped exposed metal heaters|
|US7832484||Apr 18, 2008||Nov 16, 2010||Shell Oil Company||Molten salt as a heat transfer fluid for heating a subsurface formation|
|US7841401||Oct 19, 2007||Nov 30, 2010||Shell Oil Company||Gas injection to inhibit migration during an in situ heat treatment process|
|US7841408||Apr 18, 2008||Nov 30, 2010||Shell Oil Company||In situ heat treatment from multiple layers of a tar sands formation|
|US7841425||Nov 30, 2010||Shell Oil Company||Drilling subsurface wellbores with cutting structures|
|US7845411||Dec 7, 2010||Shell Oil Company||In situ heat treatment process utilizing a closed loop heating system|
|US7849922||Dec 14, 2010||Shell Oil Company||In situ recovery from residually heated sections in a hydrocarbon containing formation|
|US7860377||Apr 21, 2006||Dec 28, 2010||Shell Oil Company||Subsurface connection methods for subsurface heaters|
|US7866385||Apr 20, 2007||Jan 11, 2011||Shell Oil Company||Power systems utilizing the heat of produced formation fluid|
|US7866386||Oct 13, 2008||Jan 11, 2011||Shell Oil Company||In situ oxidation of subsurface formations|
|US7866388||Jan 11, 2011||Shell Oil Company||High temperature methods for forming oxidizer fuel|
|US7912358||Apr 20, 2007||Mar 22, 2011||Shell Oil Company||Alternate energy source usage for in situ heat treatment processes|
|US7931086||Apr 18, 2008||Apr 26, 2011||Shell Oil Company||Heating systems for heating subsurface formations|
|US7942197||Apr 21, 2006||May 17, 2011||Shell Oil Company||Methods and systems for producing fluid from an in situ conversion process|
|US7942203||May 17, 2011||Shell Oil Company||Thermal processes for subsurface formations|
|US7950453||Apr 18, 2008||May 31, 2011||Shell Oil Company||Downhole burner systems and methods for heating subsurface formations|
|US7986869||Apr 21, 2006||Jul 26, 2011||Shell Oil Company||Varying properties along lengths of temperature limited heaters|
|US8011451||Sep 6, 2011||Shell Oil Company||Ranging methods for developing wellbores in subsurface formations|
|US8027571||Sep 27, 2011||Shell Oil Company||In situ conversion process systems utilizing wellbores in at least two regions of a formation|
|US8042610||Oct 25, 2011||Shell Oil Company||Parallel heater system for subsurface formations|
|US8070840||Apr 21, 2006||Dec 6, 2011||Shell Oil Company||Treatment of gas from an in situ conversion process|
|US8083813||Dec 27, 2011||Shell Oil Company||Methods of producing transportation fuel|
|US8113272||Oct 13, 2008||Feb 14, 2012||Shell Oil Company||Three-phase heaters with common overburden sections for heating subsurface formations|
|US8146661||Oct 13, 2008||Apr 3, 2012||Shell Oil Company||Cryogenic treatment of gas|
|US8146669||Oct 13, 2008||Apr 3, 2012||Shell Oil Company||Multi-step heater deployment in a subsurface formation|
|US8151880||Dec 9, 2010||Apr 10, 2012||Shell Oil Company||Methods of making transportation fuel|
|US8151907||Apr 10, 2009||Apr 10, 2012||Shell Oil Company||Dual motor systems and non-rotating sensors for use in developing wellbores in subsurface formations|
|US8162059||Apr 24, 2012||Shell Oil Company||Induction heaters used to heat subsurface formations|
|US8162405||Apr 24, 2012||Shell Oil Company||Using tunnels for treating subsurface hydrocarbon containing formations|
|US8172335||May 8, 2012||Shell Oil Company||Electrical current flow between tunnels for use in heating subsurface hydrocarbon containing formations|
|US8177305||Apr 10, 2009||May 15, 2012||Shell Oil Company||Heater connections in mines and tunnels for use in treating subsurface hydrocarbon containing formations|
|US8191630||Apr 28, 2010||Jun 5, 2012||Shell Oil Company||Creating fluid injectivity in tar sands formations|
|US8192682||Apr 26, 2010||Jun 5, 2012||Shell Oil Company||High strength alloys|
|US8196658||Jun 12, 2012||Shell Oil Company||Irregular spacing of heat sources for treating hydrocarbon containing formations|
|US8205674||Jun 26, 2012||Mountain West Energy Inc.||Apparatus, system, and method for in-situ extraction of hydrocarbons|
|US8220539||Jul 17, 2012||Shell Oil Company||Controlling hydrogen pressure in self-regulating nuclear reactors used to treat a subsurface formation|
|US8224165||Jul 17, 2012||Shell Oil Company||Temperature limited heater utilizing non-ferromagnetic conductor|
|US8225866||Jul 21, 2010||Jul 24, 2012||Shell Oil Company||In situ recovery from a hydrocarbon containing formation|
|US8230927||May 16, 2011||Jul 31, 2012||Shell Oil Company||Methods and systems for producing fluid from an in situ conversion process|
|US8233782||Jul 31, 2012||Shell Oil Company||Grouped exposed metal heaters|
|US8240774||Aug 14, 2012||Shell Oil Company||Solution mining and in situ treatment of nahcolite beds|
|US8256512||Oct 9, 2009||Sep 4, 2012||Shell Oil Company||Movable heaters for treating subsurface hydrocarbon containing formations|
|US8261832||Sep 11, 2012||Shell Oil Company||Heating subsurface formations with fluids|
|US8267170||Sep 18, 2012||Shell Oil Company||Offset barrier wells in subsurface formations|
|US8267185||Sep 18, 2012||Shell Oil Company||Circulated heated transfer fluid systems used to treat a subsurface formation|
|US8272455||Sep 25, 2012||Shell Oil Company||Methods for forming wellbores in heated formations|
|US8276661||Oct 2, 2012||Shell Oil Company||Heating subsurface formations by oxidizing fuel on a fuel carrier|
|US8281861||Oct 9, 2012||Shell Oil Company||Circulated heated transfer fluid heating of subsurface hydrocarbon formations|
|US8327681||Dec 11, 2012||Shell Oil Company||Wellbore manufacturing processes for in situ heat treatment processes|
|US8327932||Apr 9, 2010||Dec 11, 2012||Shell Oil Company||Recovering energy from a subsurface formation|
|US8353347||Oct 9, 2009||Jan 15, 2013||Shell Oil Company||Deployment of insulated conductors for treating subsurface formations|
|US8381815||Apr 18, 2008||Feb 26, 2013||Shell Oil Company||Production from multiple zones of a tar sands formation|
|US8434555||Apr 9, 2010||May 7, 2013||Shell Oil Company||Irregular pattern treatment of a subsurface formation|
|US8448707||May 28, 2013||Shell Oil Company||Non-conducting heater casings|
|US8459359||Apr 18, 2008||Jun 11, 2013||Shell Oil Company||Treating nahcolite containing formations and saline zones|
|US8485252||Jul 11, 2012||Jul 16, 2013||Shell Oil Company||In situ recovery from a hydrocarbon containing formation|
|US8536497||Oct 13, 2008||Sep 17, 2013||Shell Oil Company||Methods for forming long subsurface heaters|
|US8555971||May 31, 2012||Oct 15, 2013||Shell Oil Company||Treating tar sands formations with dolomite|
|US8562078||Nov 25, 2009||Oct 22, 2013||Shell Oil Company||Hydrocarbon production from mines and tunnels used in treating subsurface hydrocarbon containing formations|
|US8579031||May 17, 2011||Nov 12, 2013||Shell Oil Company||Thermal processes for subsurface formations|
|US8606091||Oct 20, 2006||Dec 10, 2013||Shell Oil Company||Subsurface heaters with low sulfidation rates|
|US8608249||Apr 26, 2010||Dec 17, 2013||Shell Oil Company||In situ thermal processing of an oil shale formation|
|US8627887||Dec 8, 2008||Jan 14, 2014||Shell Oil Company||In situ recovery from a hydrocarbon containing formation|
|US8631866||Apr 8, 2011||Jan 21, 2014||Shell Oil Company||Leak detection in circulated fluid systems for heating subsurface formations|
|US8636323||Nov 25, 2009||Jan 28, 2014||Shell Oil Company||Mines and tunnels for use in treating subsurface hydrocarbon containing formations|
|US8662175||Apr 18, 2008||Mar 4, 2014||Shell Oil Company||Varying properties of in situ heat treatment of a tar sands formation based on assessed viscosities|
|US8672027||Oct 25, 2012||Mar 18, 2014||Eog Resources Inc.||In situ fluid reservoir stimulation process|
|US8701768||Apr 8, 2011||Apr 22, 2014||Shell Oil Company||Methods for treating hydrocarbon formations|
|US8701769||Apr 8, 2011||Apr 22, 2014||Shell Oil Company||Methods for treating hydrocarbon formations based on geology|
|US8701788||Dec 22, 2011||Apr 22, 2014||Chevron U.S.A. Inc.||Preconditioning a subsurface shale formation by removing extractible organics|
|US8739874||Apr 8, 2011||Jun 3, 2014||Shell Oil Company||Methods for heating with slots in hydrocarbon formations|
|US8752904||Apr 10, 2009||Jun 17, 2014||Shell Oil Company||Heated fluid flow in mines and tunnels used in heating subsurface hydrocarbon containing formations|
|US8789586||Jul 12, 2013||Jul 29, 2014||Shell Oil Company||In situ recovery from a hydrocarbon containing formation|
|US8791396||Apr 18, 2008||Jul 29, 2014||Shell Oil Company||Floating insulated conductors for heating subsurface formations|
|US8820406||Apr 8, 2011||Sep 2, 2014||Shell Oil Company||Electrodes for electrical current flow heating of subsurface formations with conductive material in wellbore|
|US8833453||Apr 8, 2011||Sep 16, 2014||Shell Oil Company||Electrodes for electrical current flow heating of subsurface formations with tapered copper thickness|
|US8839860||Dec 22, 2011||Sep 23, 2014||Chevron U.S.A. Inc.||In-situ Kerogen conversion and product isolation|
|US8851170||Apr 9, 2010||Oct 7, 2014||Shell Oil Company||Heater assisted fluid treatment of a subsurface formation|
|US8851177||Dec 22, 2011||Oct 7, 2014||Chevron U.S.A. Inc.||In-situ kerogen conversion and oxidant regeneration|
|US8857506||May 24, 2013||Oct 14, 2014||Shell Oil Company||Alternate energy source usage methods for in situ heat treatment processes|
|US8881806||Oct 9, 2009||Nov 11, 2014||Shell Oil Company||Systems and methods for treating a subsurface formation with electrical conductors|
|US8936089||Dec 22, 2011||Jan 20, 2015||Chevron U.S.A. Inc.||In-situ kerogen conversion and recovery|
|US8967261 *||Dec 11, 2009||Mar 3, 2015||Peter James Cassidy||Oil shale processing|
|US8992771||May 25, 2012||Mar 31, 2015||Chevron U.S.A. Inc.||Isolating lubricating oils from subsurface shale formations|
|US8997869||Dec 22, 2011||Apr 7, 2015||Chevron U.S.A. Inc.||In-situ kerogen conversion and product upgrading|
|US9016370||Apr 6, 2012||Apr 28, 2015||Shell Oil Company||Partial solution mining of hydrocarbon containing layers prior to in situ heat treatment|
|US9022109||Jan 21, 2014||May 5, 2015||Shell Oil Company||Leak detection in circulated fluid systems for heating subsurface formations|
|US9022118||Oct 9, 2009||May 5, 2015||Shell Oil Company||Double insulated heaters for treating subsurface formations|
|US9033033||Dec 22, 2011||May 19, 2015||Chevron U.S.A. Inc.||Electrokinetic enhanced hydrocarbon recovery from oil shale|
|US9033042||Apr 8, 2011||May 19, 2015||Shell Oil Company||Forming bitumen barriers in subsurface hydrocarbon formations|
|US9051829||Oct 9, 2009||Jun 9, 2015||Shell Oil Company||Perforated electrical conductors for treating subsurface formations|
|US9127523||Apr 8, 2011||Sep 8, 2015||Shell Oil Company||Barrier methods for use in subsurface hydrocarbon formations|
|US9127538||Apr 8, 2011||Sep 8, 2015||Shell Oil Company||Methodologies for treatment of hydrocarbon formations using staged pyrolyzation|
|US9129728||Oct 9, 2009||Sep 8, 2015||Shell Oil Company||Systems and methods of forming subsurface wellbores|
|US9133398||Dec 22, 2011||Sep 15, 2015||Chevron U.S.A. Inc.||In-situ kerogen conversion and recycling|
|US9181467||Dec 22, 2011||Nov 10, 2015||Uchicago Argonne, Llc||Preparation and use of nano-catalysts for in-situ reaction with kerogen|
|US9181780||Apr 18, 2008||Nov 10, 2015||Shell Oil Company||Controlling and assessing pressure conditions during treatment of tar sands formations|
|US9309755||Oct 4, 2012||Apr 12, 2016||Shell Oil Company||Thermal expansion accommodation for circulated fluid systems used to heat subsurface formations|
|US20070056726 *||Sep 13, 2006||Mar 15, 2007||Shurtleff James K||Apparatus, system, and method for in-situ extraction of oil from oil shale|
|US20070209799 *||Jan 23, 2007||Sep 13, 2007||Shell Oil Company||In situ recovery from a hydrocarbon containing formation|
|US20080257552 *||Apr 17, 2008||Oct 23, 2008||Shurtleff J Kevin||Apparatus, system, and method for in-situ extraction of hydrocarbons|
|US20090071647 *||Apr 7, 2008||Mar 19, 2009||Vinegar Harold J||Thermal processes for subsurface formations|
|US20090321071 *||Apr 18, 2008||Dec 31, 2009||Etuan Zhang||Controlling and assessing pressure conditions during treatment of tar sands formations|
|US20100147521 *||Oct 9, 2009||Jun 17, 2010||Xueying Xie||Perforated electrical conductors for treating subsurface formations|
|US20100212904 *||Aug 26, 2010||Eog Resources, Inc.||In situ fluid reservoir stimulation process|
|US20110170843 *||Sep 29, 2010||Jul 14, 2011||Shell Oil Company||Grouped exposed metal heaters|
|US20110186296 *||Dec 11, 2009||Aug 4, 2011||Peter James Cassidy||Oil shale processing|
|CN101566054B||May 27, 2009||Jul 4, 2012||中国石化股份胜利油田分公司孤岛采油厂工艺研究所||Primary gravel packing tool for heat recovery|
|WO2007050476A1 *||Oct 20, 2006||May 3, 2007||Shell Internationale Research Maatschappij B.V.||Systems and methods for producing hydrocarbons from tar sands with heat created drainage paths|
|U.S. Classification||299/4, 166/259|
|International Classification||E21B43/28, E21B43/247, E21B43/26, E21B43/16|
|Cooperative Classification||E21B43/281, E21C41/24, E21B43/16, E21B43/247|
|European Classification||E21C41/24, E21B43/16, E21B43/247, E21B43/28B|