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Method of extracting hydrocarbonsRelated Patent Categories: Wells, Processes, Specific Propping Feature (epo)Method of extracting hydrocarbons description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070131423, Method of extracting hydrocarbons. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED APPLICATION [0001] This application claims priority to and is a continuation-in-part of U.S. Provisional Patent Application 60/750,265 filed Dec. 14, 2005. The complete disclosure of this related application is hereby incorporated by reference for all purposes. BACKGROUND OF THE INVENTION [0002] Field: This invention relates to methods of extracting hydrocarbons (e.g., oil and gas) from a well by fracturing the underground formation, and more particularly to methods of enhancing the extraction of hydrocarbons by inserting a liquefied gas and solvent mixture as the fracturing fluid to effect the fracture without contaminating the underground structure. [0003] The Relevant Technology: To enhance the extraction of available hydrocarbons such as oil and gas from a well, fracturing the underground formation has been an accepted practice to create pathways for the hydrocarbons to more easily migrate toward the bore. Fracturing may be accomplished by use of an explosive, by use of a gas generator which is some times called a gas gun, and hydraulically. [0004] Hydraulic fracturing or "fracing" generally involves pumping a fluid into a well through the bore at a high enough pressure and at a high enough rate to overcome leak-off of the fluid into the formation. When the pressure of the fluid being injected reaches the parting pressure of stratas in the formation, the formation will fracture. While the precise nature of the fracture will vary based on the nature of the formation, the pressures reached, and other variables, it is generally believed that the fracture has a vertically oriented primary axis and is sometimes likened to a thin wing-like structure so that the fracture may be referred to as a bi-wing fracture because it has two such wings generally opposite each other extending away from the bore. [0005] Once a fracture is induced, it is believed that the fracture will continue to propagate or extend so long as the fracturing fluid continues to be injected at a rate that exceeds the leak-off rate. That is, the formation is obviously porous so that the fracturing fluid can migrate away from the injection site at a rate (leak-off rate) that will increase as the fracture size increases allowing the fracturing fluid to be presented to an ever increasing volume/surface area. Of course, if the pumping is stopped, the injected fluid will continue to leak off into the formation, eventually allowing the induced fracture to close. [0006] In order to prevent the induced fracture from closing as the fracturing fluid dissipates into the formation, and keep the fracture pathway open for migration of hydrocarbons (e.g., oil and gas) toward the bore, a propping agent also known as a proppant is inserted into the facture to keep the fracture from closing. Proppants are typically small hard particles that can be suspended in an injecting medium and injected into the well. The proppants are quite small and come in sizes that vary from around 50 mesh to perhaps as much as 1000 mesh. The small particles are hard and thus are difficult to crush. In turn when injected into a well and forced to migrate into the cracks formed in the strata in a fracture, they prevent the strata from coming together and in turn prevent at least some portions of the fracture from closing. In effect, proppants "prop" the fracture open. Known proppants include grains of sand and manufactured aluminum oxide particles. Of course there are many other types and kinds. The proppants are generally heavier than water and will sink when mixed into a low viscosity fracturing fluid such as water. [0007] To be effective, the proppants need to be distributed throughout the fracture in the formation. Water and fracturing fluids of similar density or viscosity are not very effective in transporting the proppant throughout the entire fracture. Additives can be mixed into the low viscosity fracturing fluid to increase the viscosity and increase the ability of the mixture of fracturing fluid and the additive to retain the proppant in suspension as it moves toward the outer reaches of the fracture. Such additives include long chain polymers and materials such as guar. Cross linking of the chain can increase the viscosity and the transport properties of the mixture. See U.S. Pat. No. 7,036,597 (O'Brien, et al.) in which an alkaline crosslinked fluid is used as a second fluid in an hydraulic fracturing process. [0008] While the additives help with the transportation of the proppant, they are also believed to lodge as residue in the pores of the porous formation. In turn, the oil and gas migration may not be enhanced as much as is desired or as much as is possible. [0009] To reduce the clogging effect of the additives, a chemical breaker may be added after the proppant is injected with the higher viscosity mixture to break up the cross-linked bond and/or long hydrocarbon chains of the additives and to, in turn, allow the broken-up polymers to flow back to the bore and make way for the movement of the desired hydrocarbons toward the bore. See U.S. Pat. No. 7,036,597 (O'Brien, et al.). [0010] Liquefied gas such as carbon dioxide (CO.sub.2) and non liquefied gas like nitrogen (N.sub.2) may be separately or jointly mixed with the fracing fluid to control the viscosity of the fracturing fluid and reduce the clogging effects of the additives. [0011] Inasmuch as water is widely used as a fracturing fluid and also as a base fluid, efforts have been made to substitute methanol and add the CO.sub.2 along with polymer gels to enhance fracing and reduce water damage. That is, the water can mix with clays and other materials in the formation to again inhibit the movement of the hydrocarbons. However, such mixtures have been unsuccessful because they are not good for transporting the proppant. Further, higher viscosity fracturing fluids are believed to create a shorter and wider fracture limiting to some extent the viability of the fracturing process. [0012] To avoid the higher cost of higher viscosity fracing fluids, water has continued to be used in many processes particularly in formations that have a lower permeability. Of course, as stated, water does not transport proppant very well. In turn, the induced fracture may close resulting in a smaller effective fracture than desired. [0013] Hybrid water fractures or "fracs" are now known. That is, fluids are injected in stages. First water or other low viscosity fluid is pumped into the well to create the fracture. A second stage follows in which gel is used to distribute proppants. [0014] Both water fracs and hybrid water fracs are not producing the desired increased movement of hydrocarbons toward the bore, particularly for the formations which have a low or lower permeability. In the low permeability formations, it is believed that the water acts as a block by filling all the pores and inhibiting the migration of the hydrocarbons. In higher permeable formations, the adverse consequences of water and the clogging effect of the fluid to transport the proppant leads to disappointing results. In other circumstances, the water can mix with the clays and other materials leading to additional blockage. [0015] A fracing process is needed to increase the promulgation of the fracture and to enhance the flow of hydrocarbons, but at the same time reducing the effect of water and not inhibiting the flow rate of hydrocarbons in the formation after fracture. BRIEF SUMMARY OF THE INVENTION [0016] A hydrocarbon well (e.g., an oil and/or gas well) is formed with a bore. The bore extends from the surface into a subterranean formation. The hydrocarbons are extracted from the well (production) using a variety of known methods. To enhance or extend production from the well, a new and novel method is used to fracture the subterranean formation to enhance the flow of hydrocarbons. [0017] A reservoir means such as a tank is configured to retain a fracturing fluid. A fracturing fluid is formed by first obtaining a liquefied gas and a solvent, and mixing them to form the fracturing fluid. The fracturing fluid is positioned in the reservoir. [0018] Conduit means extends from the reservoir to the bore to communicate the fracturing fluid from the reservoir to the bore. Injecting means is provided for injecting the fracturing fluid through the conduit and into the bore. Thereafter the injecting means is operated to inject the fracturing fluid into the bore at a pressure and in a volume sufficient to induce a fracture in the subterranean formation. [0019] In a preferred method, a polymer is provided along with a proppant. The polymer is then mixed with the proppant and the resulting mixture is then positioned in the reservoir means. After the fracturing fluid has been injected in sufficiently to induce a desired fracture, the injecting means is then operated to inject the polymer-proppant mixture through the conduit means and into the bore at a pressure and in a volume sufficient to transport the polymer-proppant mixture into the fracture. [0020] In a more preferred method, the injecting means is a well-head pump and may even be a piston type positive displacement pump. In a highly preferred method, the liquefied gas is carbon dioxide. In a more preferred method the solvent is methanol. In a more highly preferred method, the fracturing fluid is comprised of from about 20 percent methanol to about 80 percent methanol with the other material being liquid carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS Continue reading about Method of extracting hydrocarbons... Full patent description for Method of extracting hydrocarbons Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method of extracting hydrocarbons patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Method of extracting hydrocarbons or other areas of interest. ### Previous Patent Application: Multiple entrance shunt Next Patent Application: Sand aggregating reagents, modified sands, and methods for making and using same Industry Class: Wells ### FreshPatents.com Support Thank you for viewing the Method of extracting hydrocarbons patent info. 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