Mobil Oil Corporation

John L Fitch

Malcolm K Strubhar

Lynn D Mullins

W D Lyle

Lloyd G Jones

William L Medlin

A continuous gravimetry survey is carried out with a gravity logging tool having a column of fluid within the tool. First and second pressure sensors are located at spaced-apart axial positions within an upper portion of the fluid column. Third and fourth pressure sensors are located at spaced-apart axial positions within a lower portion of the fluid column. The outputs from the first and second pressure sensors are differenced to produce a first pressure difference signal. The outputs of the third and fourth pressure sensors are also differenced to produce a second pressure difference signal. The difference between these first and second pressure difference signals is related to the gravity gradient along the earth formation adjacent the fluid column. Such a gravity gradient is a continuously moving gradient that is insensitive to acceleration effects from unsteady motions of the logging tool as it traverses the earth formation during the gravimetry survey.

Continuous gravity gradient logging

A method for controlling the vertical growth of hydraulic fractures in subterranean formations. The fracturing gradients of adjacent formations are determined. The fluid density necessary to inhibit the propagation of a hydraulic fracture from one adjacent formation into the other is determined from the fracturing gradients. A fracturing fluid is prepared having the necessary density for inhibiting such hydraulic fracture propagation.

Method for controlling the vertical growth of hydraulic fractures

Oil may be recovered from viscous oil-containing formations including tar sand deposits by providing at least one injection well and at least one spaced-apart production well which extend downwardly from the surface and which extend to, and generally horizontally through, the bottom of the oil-containing formation with fluid communication of the horizontally extending portions of each well with the oil-containing formation. A predetermined amount of solvent, preferably 0.05 to 0.30 pore volume is injected into the bottom of the formation via the injection well and fluids including oil are recovered from the formation via the production well. After the desired amount of solvent has been injected into the formation, production is terminated and both the injection well and production well are shut-in to allow the formation to undergo a soak period for a variable time, preferably for a time between 2 to 20 days per foot of vertical thickness of the oil-containing formation. During the soak period, there is substantial mixing of the heavy oil and the solvent in the formation by gravity-driven convection wherein the viscosity of the heavy oil is reduced, thereby making it easier to produce. A driving fluid such as water is then injected into the formation via the injection well and oil of reduced viscosity is produced until there is an unfavorable amount of driving fluid, preferably at least 90 percent.

Solvent flooding to recover viscous oils

A borehole gravimety system employs a pair of pressure transducers for lowering into a borehole along with a borehole gravity meter. The pressure transducers are spaced apart vertically within a pressure sonde for producing a pressure differential measurement of the wellbore fluid. A pressure differential measurement and a gravity reading is taken for each of a plurality of vertical locations within the borehole as the borehole gravimetry system is advanced through the borehole.

Borehole gravimetry system

A tubular member for a drill string used in the rotary drilling of deviated boreholes, which includes an outer circumferential surface which is contoured and adapted to engage the wall of the borehole so as to produce a longitudinally downward force on the drill bit upon rotation of the drill string. The tubular member may be a drill collar or section of drill pipe, wherein the contoured surface is constituted of a helical thread of a pitch which will impart a longitudinal force towards the drill bit upon rotation of the tubular member.

Tubular drill string member with contoured circumferential surface

A well casing penetrating a plurality of subterranean hydro carbon-bearing formations is perforated adjacent select ones of such hydrocarbon-bearing formations that are expected to exhibit at least a minimum pressure increase during fracturing operations. A fracturing fluid is pumped down the well through the perforations, and into the formations so as to fracture each of the select formations during a single fracturing operation.

Method for fracturing a plurality of subterranean formations

Oil may be recovered from viscous oil-containing formations including tar sand deposits by providing at least one injection well and at least one spaced-apart production well which extend downwardly from the surfaces and which extend to, and generally horizontally through, the bottom of the oil-containing formation with fluid communication of the horizontally extending portions of each well with the oil-containing formation. Solvent is injected into the injection well and fluids including oil are recovered from the production well until the fluid recovered contains an unfavorable amount of solvent, preferably at least 90 percent. After injection of the solvent is terminated, both the injection well and the production well are shut-in and the formation is allowed to undergo a soak period for a predetermined time, preferably for a time of between 2 to 20 days per foot of formation thickness. After the soak period, solvent is injected into the production well and fluids including oil are recovered from the injection well until the fluid recovered contains an unfavorable amount of solvent, preferably at least 90 percent. After injection of the solvent into the production well is terminated, both wells are shut-in and the formation is allowed to undergo a second soak period for a predetermined time, preferably for 2 to 20 days per foot of formation thickness. Thereafter, a driving fluid is injected into the formation via the injection well to effect a fluid drive of the oil through the formation and oil is produced from the production well until the oil being produced contains an unfavorable amount of driving fluid, preferably at least 90 percent.

Method of cyclic solvent flooding to recover viscous oils

Oil may be recovered from viscous oil-containing formations including tar sand deposits by first establishing a fluid communication path in the lower portion of the formation intermediate at least one injection well and a production well. A hydrocarbon solvent having a density less than oil contained in the formation and a viscosity not greater than 1/100 the viscosity of the oil contained in the formation under formation conditions is injected into the communication path and fluids including oil are recovered from the production well until the fluid recovered contains an unfavorable ratio of oil to solvent. The production well is shut-in and an additional quantity of the hydrocarbon solvent is injected into the fluid communication path, preferably until a total amount of between 0.05 to 0.30 pore volume. The injection well is then shut-in along with the production well to permit the formation to undergo a soak period for a variable time, preferably for a time of between 2 to 20 days per vertical thickness in feet of oil-containing formation. A driving fluid such as water is then injected into the formation via the injection well and the oil is produced until there is an unfavorable ratio of oil to driving fluid. During the fluid drive recovery phase, the injection well and production well may be completed to be in fluid communication with the entire portion of the formation to obtain a more uniform displacement of the upgraded formation oil by the driving fluid.

Method of solvent flooding to recover viscous oils

Disclosed is a method of producing viscous hydrocarbons from a viscous petroleum-containing subsurface formation. At least an injection well and a production well are provided to extend from the surface of the earth into the subsurface formations. A high mobility, brine-filled channel is established through the lower portion of the subsurface formation to communicate with the injection and production well. After the high mobility channel is established, a solvent for the petroleum is injected into the high mobility channel. The injection of the solvent is continued until breakthrough of the solvent at the production well and thereafter until the ratio of petroleum to solvent produced from the production well becomes unfavorable. Thereafter, gas is injected into the high mobility channel to displace the solvent and petroleum from the formation to the production well.

Solvent convection technique for recovering viscous petroleum

A method of transporting particulate solid material through a pipeline in the form of a stable foam slurry. There is formed a pumpable slurry of the particulate solid material in a stable foam carrier medium and the slurry is flowed through the pipeline to a receiving point.

Pipelining particulate solid material as stable foam slurry

This specification discloses a method of recovering thermal energy from a coal formation having a preferred vertical fracture orientation. An injection well and a production well are provided to extend into the coal formation and a vertical fracture is formed by hydraulic fracturing techniques and propagated into the coal formation to communicate with both the wells. The vertical fracture is propped in the lower portion only. A combustion-supporting gas is injected into the propped portion of the fracture and the coal is ignited. Injection of the combustion-supporting gas is continued to propagate a combustion zone along the propped portion of the fracture and hot product gases generated at the combustion zone are produced to recover the heat or thermal energy of the coal. Water may also be injected into the fracture to transport the heat resulting from the combustion of the coal to the production well for recovery.

Thermal energy production by in situ combustion of coal

This specification discloses a method of completing a well that penetrates a subterranean formation. The formation is vertically fractured and a lower portion of the fracture is propped by hydraulic fracturing techniques leaving an overlying unpropped portion of the fracture. The well is treated to block the communication of the unpropped portion of the fracture with the well.

Well completion method for controlling sand production

This specification discloses a method of completing a cased well that penetrates a subterranean formation to control the production of sand from the formation. The well is provided with perforation tunnels that extend through the casing and communicate with the formation. Removable plugs are formed in the perforation tunnels and thereafter a gravel pack is formed and consolidated in the well within the casing adjacent the perforation tunnels. Thereafter the removable plugs are removed from the perforation tunnels to provide unobstructed tunnels for the flow of fluids from the formation into the well. The formation adjacent the perforation tunnels may also be consolidated to mitigate the movement of sand from the formation into the perforation tunnels.

Well completion technique for sand control

This specification discloses a method of providing an ice structure at a desired offshore, frigid location. The structure is constructed at a first offshore location by accumulating ice on a base of naturally occurring ice. The existing extreme temperature is utilized to quickly freeze water sprayed or flooded on the base to form the accumulating ice. The base sinks under the weight of the accumulated ice to form the structure having a desired thickness. A cavity is then formed, preferably by melting, in the interior of the structure to provide the structure with sufficient buoyancy to float the structure and allow it to be towed to its desired location. There the cavity is filled with a material dense enough to again cause the structure to sink and become grounded at said desired location.

Growing community of inventors

Dallas, TX, United States of America

John L Fitch