Abstract: Method for treating a hydrocarbon containing formation are described herein. Methods may include providing heat to two or more first sections of the formation with one or more first heaters in two or more of the first sections. The provided heat may mobilize first hydrocarbons in two or more of the first sections. At least some of the mobilized first hydrocarbons are produced through production wells located in two or more second sections of the formation. The first sections and the second sections are arranged in a checkerboard pattern. A portion of at least one of the second sections proximate at least one production well is provided some heat from the mobilized first hydrocarbons, but is not conductively heated by heat from the first heaters. Heat may be provided to the second sections with one or more second heaters in the second sections to further heat the second sections.

Abstract: Methods of treating a subsurface formation are described herein. Methods for treating a subsurface treatment area in a formation may include introducing a fluid into the formation from a plurality of wells offset from a treatment area of an in situ heat treatment process to inhibit outward migration of formation fluid from the in situ heat treatment process.

Abstract: A method is provided for in-situ production of oil shale wherein a network of fractures is formed by injecting liquified gases into at least one substantially horizontally disposed fracturing borehole. Heat is thereafter applied to liquify the kerogen so that oil shale oil and/or gases can be recovered from the fractured formations.

Abstract: Methods for forming a barrier around at least a portion of a treatment area in a subsurface formation are described herein. Sulfur may be introduced into one or more wellbores located inside a perimeter of a treatment area in the formation having a permeability of at least 0.1 darcy. At least some of the sulfur is allowed to move towards portions of the formation cooler than the melting point of sulfur to solidify the sulfur in the formation to form the barrier.

Abstract: A method for treating an oil shale formation comprising dawsonite includes assessing a dawsonite composition of one or more zones in the formation. Heat from one or more heaters is provided to the formation such that different amounts of heat are provided to zones with different dawsonite compositions. The provided heat is allowed to transfer from the heaters to the formation. Fluids are produced from the formation.

Abstract: A method for underground treatment of subsurface materials comprises providing an injection pattern and a recovery pattern, the injection pattern and the recovery pattern located proximate to a subsurface treatment zone and at least one of the injection pattern and the recovery pattern comprising a plurality of lateral bores extending from a main bore. A treatment solution is injected through the injection pattern and recovered through the recovery pattern.

Abstract: A method for lowering the temperature of a portion of a subsurface formation is provided. Preferably, the formation is an oil shale formation. The method includes the step of injecting a cooling fluid under pressure into a wellbore, with the wellbore having been completed at or below a depth of the subsurface formation. In one embodiment the wellbore has an elongated tubular member for receiving the cooling fluid and for conveying it downhole to the subsurface formation. The wellbore also has an expansion valve in fluid communication with the tubular member through which the cooling fluid flows. The method then includes the steps of injecting a cooling fluid under pressure into the wellbore, and expanding the cooling fluid across the first expansion valve. In this way, the temperature of the cooling fluid is reduced. The temperature of the surrounding formation is likewise reduced through thermal conduction and convection. In another embodiment, a partially frozen slurry is used as the cooling fluid.

Abstract: A method for spacing heater wells for an in situ conversion process is provided. The method includes the steps of determining a direction along which thermal energy will travel most efficiently through a subsurface formation, and completing a plurality of heater wells in the subsurface formation, with the heater wells being spaced farther apart in the determined direction than in a direction transverse to the determined direction. In one aspect, the step of determining a direction along which thermal energy will travel most efficiently is performed based upon a review of geological data pertaining to the subsurface formation. The geological data may comprise the direction of least horizontal principal stress in the subsurface formation. Alternatively, the geological data may comprise the direction of bedding in the subsurface formation, the tilt of the subsurface formation relative to the surface topography, the organic carbon content of the kerogen, the initial formation permeability, and other factors.

Abstract: According to one embodiment, a system for accessing a subterranean zone from the surface includes a well bore extending from the surface to the subterranean zone, and a well bore pattern connected to the junction and operable to drain fluid from a region of the subterranean zone to the junction.

Abstract: A modified toe-to-heel waterflooding (TTHW) process is provided for recovering oil from a reservoir in an underground formation. After establishing the conventional TTHW waterflood, the process includes placing a chemical blocking agent at the watered out producing toe portion of the horizontal leg of the production well to create a blockage in the producing toe portion and to create a new producing toe portion in an open portion of the horizontal leg adjacent the blockage through which most of the production takes place. Production is then continued through the new producing toe portion and the open portion of the horizontal leg of the production well. These blocking and producing steps can be continued to progressively block producing toe portions in a direction toward the vertical pilot portion of the production well.

Abstract: In a WAG flood oil is displaced from a subterranean formation by injecting water alternately with gas into a single injection completion per pattern. The ratio of water to gas injected is the WAG ratio. In this invention, two separate injection completions are used in each pattern, with one placed directly above the other. A very low WAG ratio is used for injection into the bottom extremity of the formation. A very high WAG ratio is injected into the upper interval, at as high a rate as can safely be used without fracturing the formation. In the preferred embodiment, two horizontal well bores serve as the two completion intervals. Proper design of this method gives a vertical sweep efficiency of the gas that is several-fold greater than the best of previous WAG flood designs, especially in thin formations.

Abstract: A system comprising a carbon disulfide formulation storage; a mechanism for releasing at least a portion of the carbon disulfide formulation into a formation; and a mechanism for creating a pulse in the carbon disulfide formulation in the formation.

Abstract: A method for modeling fluid depletion in a reservoir is disclosed. A map is divided into cells. For each of the cells a value is stored that is based at least in part on a physical characteristic of the cell. At least one cell that contains a depletion location is identified along with a depletion amount corresponding to that location. An amount of walkers associated with the depletion location is determined. For each walker, a plurality of steps are calculated with each step to an adjacent cell. Each walker starts in the cell containing the depletion location associated with that walker. The visits of all the walkers are recorded by cell. The fluid depletion of each cell is then assessed based at least in part on the number of walker visits for each cell.

Abstract: A method is provided for in-situ gasification of coal wherein a network of fractures is formed by providing a substantially vertically disposed borehole and a plurality of substantially horizontally disposed boreholes in fluid communication with the substantially vertically disposed borehole, at least one substantially horizontally disposed boreholes being a fracturing borehole, at least one substantially horizontally disposed boreholes being an injection borehole and at least one substantially horizontally disposed boreholes being an injection borehole. An initial quantity of liquified gas is introduced into the at least one substantially horizontally disposed fracturing borehole whereby the liquified gas vaporizes forms fractures in the formation.

Abstract: A method for accessing a subterranean zone from the surface includes drilling a substantially vertical well bore from the surface to the subterranean zone and forming a slot cavity in the substantially vertical well bore proximate to the subterranean zone. The slot cavity comprises a substantially non-cylindrical shape. The method also includes drilling an articulated well bore from the surface to the subterranean zone. The articulated well bore is horizontally offset from the substantially vertical well bore at the surface and intersects the substantially vertical well bore at a junction proximate to the subterranean zone. The method may include drilling the articulated well bore to intersect the slot cavity of the substantially vertical well bore and drilling a substantially horizontal drainage pattern from the slot cavity into the subterranean zone. The subterranean zone may comprise a coal seam.

Abstract: A oil shale formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat sources may be used to heat the formation. The heat sources may be positioned within the formation in a selected pattern.

Abstract: A system for accessing a subterranean zone from an entry well including an entry well extending from the surface. The entry well has a substantially vertical portion. A one or more drainage wells extend from the entry well to a subterranean zone. A one or more articulated wells extend from the entry well to the subterranean zone. At least one of the articulated wells intersects at least one of the one or more drainage wells at a junction proximate the subterranean zone. A drainage pattern is formed coupled to the junction and operable to conduct fluids from the subterranean zone to the junction.

Abstract: A method for the storage of hydrogen within a subterranean solid carbonaceous formation such as a coal seam. At least one well extends from the surface of the earth into the formation and a pressure gradient extends from the formation to the well to desorb methane within the formation and flow the methane into the well. Subsequent to recovery of the methane from the formation, gaseous hydrogen is injected into the well and into the formation. The injection of hydrogen is carried out under a pressure sufficient to cause the injected hydrogen to become absorbed within the matrix of the carbonaceous formation. Subsequent to storage of the hydrogen, a pressure gradient is established from the formation to the surface to withdraw previously introduced hydrogen to the surface. At least one common well is used for recovery of methane from the formation and introduction of hydrogen into the formation.

Abstract: A method for treating a hydrocarbon containing formation is provided. In one embodiment, heat from one or more heaters may be provided to at least a portion of the formation. Heat may be allowed to transfer from the one or more heaters to at least a part of the formation. In certain embodiments, the heat from the one or more heaters may pyrolyze at least some hydrocarbons in the formation. In an embodiment, a first fluid may be introduced into at least a portion of the formation. The portion may have previously undergone an in situ conversion process. A mixture of the first fluid and a second fluid may be produced from the formation. Such mixture may, in some embodiments, be treated or burned.

Abstract: An in situ process for treating a diatomite formation is provided. The process may include providing heat from one or more heaters to at least a portion of the formation. The heat may be allowed to transfer from the one or more heaters to a part of the formation such that heat from the one or more heat sources pyrolyzes at least some hydrocarbons within the part. Hydrocarbons may be produced from the formation.

Abstract: The present invention relates generally to subterranean well construction, and more particularly, to improved methods for producing gas from subterranean formations that include coal seams. The method according to the present invention includes the steps of drilling at least one substantially vertical well bore intersecting the coal seam, drilling at least one substantially horizontal well bore disposed substantially within the coal seam and exiting from the at least one substantially vertical well bore, and fracturing the coal seam along the at least one substantially horizontal well bore using a hydrajetting tool to produce a plurality of fractures. The plurality of fractures is spaced to maximize interference between the fractures and enhances the production of gas from the coal seam of the subterranean formation. A plurality of substantially horizontal well bores can also be drilled.

Abstract: A method for treating a hydrocarbon containing formation is provided. In one embodiment, heat from one or more heaters may be provided to at least a portion of the formation. Heat may be allowed to transfer from the one or more heaters to at least a part of the formation. In certain embodiments, the heat from the one or more heaters may pyrolyze at least some hydrocarbons within the formation. In an embodiment, a first fluid may be introduced into at least a portion of the formation. The portion may have previously undergone an in situ conversion process. A mixture of the first fluid and a second fluid (or a second compound) may be produced from the formation. In some embodiments, a first fluid may be provided to the formation prior to pyrolyzing hydrocarbons in the formation, and a second fluid (or a second compound) may be produced prior to pyrolyzing hydrocarbons in the formation.

Abstract: A well system includes at least two well bores extending from a surface to a subterranean zone. Each of the two well bores is used to form a well bore pattern for the subterranean zone that intersects the other well bore and transports fluid from the subterranean zone to the other well bore for production to the surface. In addition, each of the two well bores is operable to collect fluids transported to the well bore by the well bore pattern formed through the other well bore for production to the surface.

Abstract: A method for treating a relatively permeable formation containing heavy hydrocarbons in situ may include providing heat from one or more heat sources to a portion of the formation. The heat may be allowed to transfer from the heat sources to a selected section of the formation. The transferred heat may pyrolyze at least some hydrocarbons within the selected section. A mixture of hydrocarbons may be produced from the selected section. In some embodiments, pressure may be controlled to produce a desired property in the produced mixture.

Abstract: A coal containing formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat sources within a relatively thin layer of coal may be positioned in a staggered pattern near to edges of the layer so that superposition of heat from the heat sources allows a large percentage of the layer to reach a desired temperature.

Abstract: In accordance with one embodiment of the present invention, a method is provided for accessing a plurality of subterranean zones from the surface. The method includes forming an entry well from the surface. Two or more exterior drainage wells from the entry well through the plurality of subterranean zones are formed. At least one exterior drainage well is operable to drain fluid from the plurality of subterranean zones.

Abstract: A hydrocarbon containing formation may be treated using an in situ thermal process. Hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat sources may be positioned within open wellbores in the formation.

Abstract: A method is described for inhibiting migration of fluids into and/or out of a treatment area undergoing an in situ conversion process. Barriers in the formation proximate a treatment area may be used to inhibit migration of fluids. Inhibition of migration of fluids may occur before, during, and/or after an in situ treatment process. For example, migration of fluids may be inhibited while heat is provided from heaters to at least a portion of the treatment area. Barriers may include naturally occurring portions (e.g., overburden, and/or underburden) and/or installed portions.

Abstract: An in situ process for treating an oil containing formation is provided. The process may include providing heat from one or more heaters to at least a portion of the formation. The heat may be allowed to transfer from the one or more heaters to a part of the formation such that heat from the one or more heat sources pyrolyzes at least some hydrocarbons within the part. Hydrocarbons may be produced from the formation.

Abstract: A method for treating a hydrocarbon containing formation is described. The method for treating a hydrocarbon containing formation may include heating a first volume of the formation using a first set of heaters. A second volume of the formation may be heated using a second set of heaters. The first volume may be spaced apart from the second volume by a third volume of the formation. The first volume, second volume, and/or third volume may be sized, shaped, and/or located to inhibit deformation of subsurface equipment caused by geomechanical motion of the formation during heating.

Abstract: Hydrocarbons are recovered from a subterranean reservoir by drilling an injection well bore having an outlet in the reservoir and drilling a production well bore spaced apart from the injection well bore and having an inlet in the reservoir. A permeable zone having a first patterned web of channels radiating outwardly from the outlet of the injection well and connecting to a second patterned web of channels radiating outwardly from the inlet of the production well is formed in the reservoir. Heated fluid is passed from the outlet into the permeable zone to mobilize hydrocarbons in the subterranean reservoir so that the mobilized hydrocarbons flow toward the inlet. The permeable zone fans out from the wells to cover an extended area of the reservoir to enhance hydrocarbon recovery by heating hydrocarbons from an expanded area of a reservoir and gravity draining the hydrocarbons.

Abstract: An in situ process for treating a tar sands formation is provided. The process may include providing heat from one or more heaters to at least a portion of the formation. The heat may be allowed to transfer from the one or more heaters to a part of the formation such that heat from the one or more heat sources pyrolyzes at least some hydrocarbons within the part. Hydrocarbons may be produced from the formation.

Abstract: A method and apparatus for exploiting oilfields involving the installation of a well network in the form of an open or non-open ring that is generally non-circular. Horizontal well sections (3) are drilled from vertical injection (1) or producing (2) wells that already exist, to interlink them. The vertical wells that are located in the same line are used as injection wells, thereby promoting oil sweeping in the reservoir (R) towards the ring-shaped producing wells (P1) or (P2). In another embodiment, vertical service wells are drilled for monitoring the characteristics of the reservoir (R). From these wells, horizontal wells are drilled in a ring-shaped form to obtain concentric well rings from the periphery to the central region of the reservoir (R). The outermost horizontal well is used as injection well and the innermost annular horizontal wells are used as producing wells.

Abstract: A method for treating a relatively permeable formation containing heavy hydrocarbons in situ may include providing heat from one or more heat sources to a portion of the formation. The heat may be allowed to transfer from the heat sources to a selected section of the formation. The transferred heat may pyrolyze at least some hydrocarbons within the selected section. A mixture may be produced from the selected section. A quality of the produced mixture may be controlled by varying a location for producing the mixture.

Abstract: An oil shale formation may be treated using an in situ thermal process. Heat may be provided to the treatment area from one or more heat sources. A heat source may be positioned in an uncased wellbore. Heat may be allowed to transfer from the heat source to a section of the formation. Subsequently, hydrocarbons, H2, and/or other formation fluids may be produced from the formation.

Abstract: A system for accessing a subterranean zone from the surface includes an entry well bore extending down from the surface. A plurality of slanted well bores extend from the entry well bore to the subterranean zone. Drainage patterns extend from the slanted well bores into the subterranean zone.

Abstract: A method for treating a relatively low permeability formation containing heavy hydrocarbons in situ may include providing heat from one or more heat sources to a portion of the formation. The heat may be allowed to transfer from the heat sources to a selected section of the formation. The transferred heat may pyrolyze at least some hydrocarbons within the selected section. A mixture of hydrocarbons may be produced from the selected section. In certain embodiments, one or more heat sources may be placed in an uncased wellbore.

Abstract: An oil shale formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat may also be applied to the formation to increase a permeability of the formation. In some embodiments, the permeability of a portion of the formation may increase to a relatively high permeability as compared to the initial permeability.

Abstract: An oil shale formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a desired temperature. A heating rate for a selected volume of the formation may be controlled by altering an amount of heating energy per day that is provided to the selected volume.

Abstract: A method for treating a relatively permeable formation containing heavy hydrocarbons in situ may include providing heat from one or more heat sources to a portion of the formation. The heat may be allowed to transfer from the heat sources to a selected section of the formation. The transferred heat may pyrolyze at least some hydrocarbons within the selected section. A mixture of hydrocarbons may be produced from the selected section. In some embodiments, a reducing environment may be maintained in a portion of the formation.

Abstract: A hydrocarbon containing formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. Heat may also uniformly increase a porosity of a treated portion of the formation.

Abstract: A method and system for accessing subterranean resources from a limited surface area includes a first well bore extending from the surface to the target zone. The first well bore includes an angled portion disposed between the target zone and the surface to provide an offset between a surface location of the first well bore and an intersection of the first well bore with the subterranean resource. The system also includes an articulated well bore extending from the surface to the target zone. The articulated well bore is offset from the first well bore at the surface and intersects the first well bore proximate the target zone. The system further includes a well bore pattern extending from the intersection of the first well bore and the articulated well bore in the target zone to provide access to the target zone.

Abstract: An oil shale formation may be treated using an in situ thermal process. Fluid migration into and/or out of a treatment area in the formation may be inhibited. In some embodiments, a barrier may be used to inhibit migration of fluids into and/or out of the treatment area. Heat may be provided to the treatment area and subsequently, hydrocarbons, H2, and/or other formation fluids may be produced from the formation.

Abstract: A drainage system for accessing multiple subterranean zones from the surface includes an entry well extending from the surface. The system also includes two or more exterior drainage wells extending from the entry well through the subterranean zones. The exterior drainage wells each extend outwardly and downwardly from the entry well for a first selected distance and then extend downwardly in a substantially vertical orientation for a second selected distance.

Abstract: A coal formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a synthesis gas production temperature. A synthesis gas producing fluid may be introduced into the formation to generate synthesis gas. Synthesis gas may be produced from the formation in a batch manner or in a substantially continuous manner.

Abstract: In an embodiment, a method of treating a kerogen and liquid hydrocarbon containing formation in situ may include providing heat from one or more heat sources to at least a portion of the formation. Heat may be allowed to transfer from the one or more heat sources to a part of the formation. In some embodiments, at least a portion of liquid hydrocarbons in the part may be mobilized. At least a portion of kerogen in the part may be pyrolyzed. In certain embodiments, a pressure within at least a part of the formation may be controlled. The pressure may be controlled to be at least about 2.0 bars absolute. A mixture may be produced from the formation.

Abstract: An oil shale formation may be treated using an in situ thermal process. Heat may be provided to a portion of the formation from one or more heat sources. Heat may be allowed to transfer from the heat sources to a selection of the formation. Hydrocarbons, H2, and/or other formation fluids may be produced from the formation. A recovery fluid may be provided to the formation to recover one or more components remaining in the portion.

Abstract: A hydrocarbon containing formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. A reducing environment may be maintained within a portion of the formation.

Abstract: An oil shale formation may be treated using an in situ thermal process. Heat may be provided to the treatment area. Fluids may be injected into the formation to remove a component within the formation. Hydrocarbons, H2, and/or other formation fluids may be produced from the formation. In some embodiments, fluids may be injected prior to production of formation fluids. Alternatively, fluids may be injected after production of formation fluids.

Abstract: A hydrocarbon containing formation may be treated using an in situ thermal process. A mixture of hydrocarbons, H2, and/or other formation fluids may be produced from the formation. Heat may be applied to the formation to raise a temperature of a portion of the formation to a pyrolysis temperature. An average temperature and/or pressure within the formation may be controlled to inhibit production of hydrocarbons that have carbon numbers greater than a selected carbon number. In some embodiments, the selected carbon number is 25. A small number of hydrocarbons having carbon numbers greater than the selected carbon number may be entrained in vapor produced from the formation.