354 results about "Tight oil" patented technology

The invention discloses a method for optimizing tight oil horizontal well crack network parameters through the transformation volume, and belongs to the field of tight oil horizontal well reservoirs. According to the method, according to a tight reservoir, firstly, the geologic feature of the reservoir is evaluated, the specific reservoir condition for volume fracture to form a volume crack network system is explicated, then, the influences of different transformation volumes and crack arrangement modes of horizontal well volume fracture on capacity are studied, and the specific crack network parameters are optimized. The method at least includes the steps that firstly, a basic crack network feature comprehensive evaluation method for tight reservoir volume fracture is established; secondly, a capacity prediction and simulation model method for tight oil volume fracture is established. The tight oil layer horizontal well fracture crack network parameters are optimized through the transformation volume formed in the fracture process, the transformation volume is formed in a tight oil layer, a matrix seeps towards a crack at the shortest distance, the driving pressure of effective flow is greatly reduced, and flow under the extremely-low permeability condition is achieved; the single well capacity can be greatly improved.

Embodiments of the invention provide methods and composition for stimulating a hydrocarbon-bearing, heavy oil containing formation, a deep oil reservoir, or a tight oil reservoir, whereby exothermic reactants are utilized to generate in-situ steam and nitrogen gas downhole in the formation or the reservoir as an enhanced oil recovery process. An oil well stimulation method is provided, which includes injecting, into the one of the formation and the reservoir, an aqueous composition including an ammonium containing compound and a nitrite containing compound. The method further includes injecting, into the one of the formation and the reservoir, an activator. The activator initiates a reaction between the ammonium containing compound and the nitrite containing compound, such that the reaction generates steam and nitrogen gas, increasing localized pressure and improving oil mobility, in the one of the formation and the reservoir, thereby enhancing oil recovery from the one of the formation and the reservoir.

The invention relates to a tight oil flow simulation and permeability prediction method based on a pore network model. The method includes the following steps: (1) scanning a tight core to obtain a two-dimensional electron microscope image and obtain spatial geometric information of porous medium pores; (2) reconstructing a digital core to obtain a geometric data file of the digital core; (3) extracting the pore network model of the digital core to obtain a data file of the pore network model of the tight core; (4) obtaining the pressure at each pore and the volume flow rate at each pore throat position to further obtain the flowing condition of a fluid in the nano-scale pore network model; (5) obtaining the volume flow rate Q of the fluid at the outlet end of the pore network model and calculating the apparent permeability of the pore network model according to the Darcy law. The newly developed pore network model overcomes the shortcoming that the traditional pore network model cannot consider the boundary slip and the change of the effective viscosity of the fluid when the fluid flows in the nanopores.

The invention discloses a method for evaluating hydrocarbon potential key parameters of high-quality hydrocarbon-source rock, and belongs to the technical field of oil and gas resource evaluation. The method includes the key steps of firstly, determining an immature and low-mature oil hydrocarbon expelling threshold, a normal hydrocarbon threshold and a normal hydrocarbon expelling threshold of high-quality hydrocarbon-source rock according to geochemistry data of hydrocarbon-source rock; secondly, establishing the hydrocarbon-source rock hydrocarbon amount and a hydrocarbon rate evaluating model; thirdly, establishing the hydrocarbon-source rock hydrocarbon expelling amount and a hydrocarbon expelling evaluating model, and evaluating the target level hydrocarbon-source rock hydrocarbon expelling amount and hydrocarbon expelling rate key parameters; fourthly, establishing a high-quality hydrocarbon-source rock organic carbon recovery coefficient evaluating model, and evaluating a target level hydrocarbon-source rock organic carbon recovery coefficient; fifthly, evaluating a research area target level high-quality hydrocarbon-source rock hydrocarbon potential plane graph, and analyzing the relation between the plane graph and tight oil hydrocarbon contribution. Immature and low-mature stage hydrocarbon potential key parameters of high-quality hydrocarbon-source rock are subjectively and accurately evaluated, and the blank, weakened by people in the past, of immature and low-mature stage hydrocarbon of high-quality hydrocarbon-source rock is filled in.

The present invention relates to an oil-base imitating drilling fluid with characteristics of strong inhibition, strong blocking and high lubricity. In the prior art, the existing amine compound-containing water-base drilling fluid provides the weak blocking capability for the mud shale micro-crack, and the lubricity can not completely meet the construction requirement. With the oil-base imitating drilling fluid of the present invention, the problems in the prior art are mainly solved. The oil-base imitating drilling fluid comprises, by weight, 100 parts of water, 1-5 parts of bentonite, 1-3 parts of an ammonium salt filtrate reducer, 1-2 parts of a resin filtrate reducer, 1-2 parts of an oligomer shale inhibitor, 2-3 parts of an alcohol shale inhibitor, 0.2-0.4 part of a coating agent, 1-2 parts of an asphalt blocking agent, 1-2 parts of ultra-fine calcium carbonate, 0.1-0.5 part of a flow type adjusting agent, 0.01-0.04 part of a pH value adjusting agent, and 1-4 parts of a lubricant. According to the present invention, the oil-base imitating drilling fluid of the present invention is the water-base drilling fluid having the performance equivalent to the oil-base drilling fluid, the safe, rapid and efficient drilling construction in the mud shale stratum and the unconventional dense oil reservoir is ensured, and the new technical support is provided for the effective development of the oil and gas reservoir.

The invention discloses a method for evaluating the volume transformation capacity of a vertical well of a fractured tight oil reservoir. The method comprises the following steps: forming a transformation fracture network near a well bore, wherein the transformation region is divided into two parts, namely an inner area and an outer area, the inner area is an artificial main fracture transformation region, and the flow conductivity of an artificial main fracture is much higher than external supply, so that the region is assumed to have limited artificial main factures during a model derivation process, the attribute parameters of all factures are consistent, and the seepage of the fluid in a main fracture is linear seepage and follows the Darcy law; under the combined action of artificial fracture extending and reservoir rock brittle shear, the artificial fractures, shear fractures and natural fractures are criss-cross, so that the seepage mode of the region is changed into fracture conductivity primarily; a semi-analytical two-region comprehensive mathematical model which can be used for evaluating the volume transformation capacity of the vertical well is established. The method is applicable to evaluating multi-fracturing of the vertical well of a closed boundary fractured reservoir and the volume transformation of the vertical well of the fractured tight oil reservoir; reference is provided for reasonable development of the tight oil reservoir.

The invention provides a hydraulic fracturing treatment method of an unconventional reservoir oil and gas well. The hydraulic fracturing treatment method comprises the following steps: injecting a material liquid into existing fractures of a reservoir; enabling a temporary plugging material in the material liquid to form bridge blinding at the seams of the fractures; performing hydraulic fracturing construction to force the fractures to turn; and injecting an active liquid to activate microfractures of the reservoir, and the steps are performed at least once. By the adoption of the hydraulic fracturing treatment method of the unconventional reservoir oil and gas well, not only can a plurality of man-made fractures be formed, the microfractures of the reservoir can be activated, the drainage area is enlarged, and the single-well yield and the economic benefits are improved. The hydraulic fracturing treatment method provided by the invention is not only suitable for unconventional oil and gas reservoirs such as shale gas, coal bed gas and tight oil and gas but also applied to low-permeability and superlow-permeability conventional oil and gas reservoirs; and meanwhile, the method can be used for straight-well capacity increasing revamp construction and can also be used for capacity increasing revamp construction of horizontal wells, deviated wells and the like.

The invention discloses a multi-level evaluation method of horizontal-well volume fracturing effect influence factors. The method sequentially includes the following steps: 1) establishing an evaluation index database, which includes a sample set, a fracturing effect influence factor set and an evaluation index main-factor set; 2) establishing a multi-level evaluation system according to the evaluation index database; 3) utilizing a grey correlation analysis method to calculate all influence factor weight coefficients in the multi-level evaluation system, sorting the same to clarify primary-secondary relationships, and evaluating a fracturing effect; and 4) calculating a comprehensive reservoir evaluation factor, classifying reservoirs where all fracturing wells are located, and evaluatingthe fracturing effect. According to the method, the factors of volume-fracturing horizontal-well reservoir physical-properties, fracturing construction and production dynamics and the like are comprehensively considered, a purpose of multi-level evaluation on the horizontal-well volume fracturing effect influence factors is achieved through calculating the weight coefficients of all the influencefactors of different levels and the comprehensive reservoir evaluation factor, and an important guiding role is played on horizontal-well volume fracturing optimization design and development of tight oil reservoirs.

The invention provides a method for forming multiple fractures by forced planar diverting of a fracture opening being temporarily plugged. The method includes: allowing temporary plugging diverting material fluid to a position near the fracture opening in a reservoir so as to form a bridge plug and force the fracture to divert, forming multiple fractures, activating micro-fractures of the reservoir with active liquid or acid liquid, and forming a multi-fracture mesh. The method according to the technical scheme has the advantages that artificial fractures in unconventional oil-gas reservoirs, such as low-permeability and ultralow-permeability oil-gas reservoirs, tight oil reservoirs and shale oil-gas reservoirs, are forced to divert in the plane, forming multiple artificial fractures having guiding ability, chances to connect reservoir bodies are increased, drainage area is enlarged, cleaning diverting material is of degradability and can fully degrade after construction, all the fractures can be utilized, and yield increase is more obvious.

The invention provides a method for improving recovery efficiency through huff and puffoil recovery of a tight oil fractured horizontal well. When reservoir pressure is reduced to a certain optimized pressure, the horizontal well is subjected to sand washing out and well flushing, water is injected into the reservoir at the specified daily water-injection rate, water injection is stopped when pressure at the end of injection life is maintained to be 100%, and then the accumulated water-injection rate is equal to accumulated fluid withdrawal rate in the previous production stage of the well; after water injection is ended, the horizontal well is closed and enters a closing-in stage to depend on imbibition replacement and other effects, so that crude reservoir oil enters a high-permeability channel; and during oil extraction, when formation pressure in the control area of the horizontal well is reduced to rated pressure, the well is closed, and second round of huff and puff oil recovery is performed. According to the method for improving recovery efficiency through the huff and puffoil recovery of the tight oil fractured horizontal well disclosed by the invention, crude oil in dense reservoir rock matrix pores developed in natural fracture is further extracted, the single well yield of an oil well is improved by comprehensively utilizing formation energy rising, injected water and crude reservoir oil imbibition replacement and other principles, and a new approach is developed for increasing the crude oil recovery rate of the dense oil reservoir.

Novel nanoparticle catalysts comprising alumina nanoparticles doped with silicon, nanofluids containing the nanoparticle catalysts, processes for their preparation, as well as methods of their use in treating light tight oil wells having fractures and the oils produced by the wells post are disclosed. The novel nanocatalysts are useful, inter alia, improving well production, extending the time between fracturings, reducing well treatment costs associated with improving well production and or reducing equipment down time.

The invention provides a staggered well arranging method for ultra-low permeability tight oil reservoir volume fracturing horizontal well quasi-natural energy exploitation. The method comprises the steps of 1) firstly carrying out comprehensive geological research, selecting a horizontal well network deployment area preferably, carrying out reservoir classification evaluation, and determining a main contribution interval; 2) optimizing the horizontal segment length; 3) optimizing the well spacing; 4) optimizing the segment distance between fracturing fractures; 5) determining the array distance. The method can utilize the natural energy oil drainage function of horizontal well volume fracturing fracture networks to the greatest degree and avoids the risk of water breakthrough in water flooding exploitation; volume fracturing retention fluid achieves the effects of replenishing energy at an early stage.

The invention provides a method for determining the nuclear magnetic resonance T2 cutoff value and the fluid saturation of tight oil, and an apparatus thereof. The method comprises the following steps: determining the carbon content of a sample to be measured to generate a carbon content determination result; determining the lower limit value of the pore throat radius of the sample to be measured according to the carbon content determination result; and determining the corresponding T2 cutoff value according to the lower limit value of the pore throat radius and the core relaxation rate of the sample to be measured. The T2 cutoff value is calculated by using the lower limit value of the pore throat radius of the tight oil movable fluid of the practical sample in the above scheme, and the lower limit value of the pore throat radius of the tight oil movable fluid of the practical sample is determined by adopting a course to fine pore throat carbon content gradual approximation technology, so the T2 cutoff value obtained in the invention is true.

The invention discloses a tight oil productivity prediction method considering stress interference and fracturing fluid filtration loss and a tight oil productivity prediction system thereof. The tight oil productivity prediction method comprises the steps that basic parameters are acquired; influence data of inducted stress generated by each stage of fracturing crack on ground stress in tight oil horizontal well multistage fracturing are calculated; the influence data of fracturing fluid in a reservoir matrix on reservoir matrix pore pressure are calculated after fracturing construction; the influence data of stress interference and filtration loss on the artificial crack size are calculated; the influence data of stress interference and filtration loss on artificial crack permeability are calculated; and a tight oil productivity prediction model is constructed and a tight oil productivity prediction result is acquired.

The invention discloses an evaluation method for tight oil well reserves, and relates to the technical field of oil and gas exploration and development. The problem that the prediction precision of the tight oil well reserves is low is mainly solved. Geological factors of a tight oil well region and the exploration states of tight oil wells are utilized for grading different tight oil wells to obtain the abundance of each tight oil well in each grade of tight oil wells, through calculating the abundance planar distribution, the economic coefficient of each tight oil well in each grade of tight oil wells is obtained, then through the economic coefficients, all the grades of tight oil wells are divided into different types, and on the basis of the area of each type tight oil well in each grade of tight oil wells and the abundance of each type tight oil well in each grade of tight oil wells, the reserves of all the types of tight oil wells in all the grades of tight oil wells are finally obtained. The evaluation method for the tight oil well reserves effectively improves the prediction precision of the tight oil reserves.

The invention provides a method for testing the tight oil occurrence state of a reservoir stratum through CT quantitative and three-dimensional visualization. The method comprises the following steps of providing fresh rock core samples in the reservoir stratum; performing CT scan on rock cores so as to obtain two-dimensional slicing images; differentiating out tight oil, water, rock particles and holes by grey scales, and performing digital reconstruction on the two-dimensional slicing images so as to obtain three-dimensional images; and dividing the tight oil into different occurrence states, performing statistics on the volume of the tight oil in each occurrence state, and analyzing the volume or the mass of the tight oil in each occurrence state. Through the adoption of the method, the microcosmic occurrence state of the impact oil in a micro nanometer pore throat can be quantitatively analyzed.

The invention discloses a multifunctional multi-field coupled seepage experiment device. The multifunctional multi-field coupled seepage experiment device comprises a device body, a stress field control system, a temperature field control system, a fluid loading control system and a fluid seepage measurement system. The invention further discloses seepage experiments performed on tight gas, shale gas, tight oil, shale oil, natural gas hydrate and geothermal heat in a multi-field coupled state of a temperature field, a stress field, a pore pressure field and a seepage field. The invention has the beneficial effects: the temperature and pressure needs of the tight gas, the shale gas, the tight oil and the shale oil are met, and more importantly, it meets the high temperature need of geothermal heat exploitation can be met while the low temperature need of a natural gas hydrate flow test is met; a real stratum environment is simulated, and the exploitation seepage experiments of unconventional energy resources such as the tight gas, the shale gas, the tight oil, the shale oil, the natural gas hydrate, a dry hot rock and the like can be completed respectively by using the same equipment.

The invention provides a method for selecting a refracturing target well of a tight oil and gas reservoir. The method comprises the following steps of: determining a well completion efficiency of a well to be screened; determining the unit reservoir quality of the well to be screened; using the unit reservoir quality as a horizontal ordinate and the well completion efficiency as a longitudinal ordinate to draw a scatter diagram of the well completion efficiency and the unit reservoir quality; using transverse and longitudinal division lines for dividing the scatter diagram of the well completion efficiency and the unit reservoir quality into four parts to form an intersection diagnosis diagram, wherein the left upper part of the intersection diagnosis diagram is a re-examination development necessity region; the right upper part of the intersection diagnosis diagram is a high-productivity well high-refracturing-risk region; the left lower part of the intersection diagnosis diagram is a current stage non-considering region; the right lower part of the intersection diagnosis diagram is an optimum refracturing well region; the transverse division lines select straight lines with the well completion efficiency being 50 percent; and the longitudinal division lines are selected according to economic benefits; performing judgment on the basis of the intersection diagnosis diagram; and completing the selection of the refracturing target well of the tight oil and gas reservoir. The method has the advantage that the refracturing target well can be fast and effectively selected.

The embodiment of the invention provides a method and device for predicting the recoverable reserve of tight oil in a to-be-valuated region. According to the method provided by the embodiment of the invention, the single-well recoverable reserve of the tight oil is reasonably predicted by utilizing production situations of producing wells already put into operation in the adjacent regions of the to-be-valuated region and by combining with the change of geological factors simultaneously and main controlling factors of the to-be-valuated region are optimally selected by utilizing correlation analysis to ensure that the inapplicability problem of using same geological parameters to predict the single-well EUR (Estimated Ultimate Recovery) of the tight oil in previous geological prediction models is avoided; moreover, the coefficients of the geological parameters in the EUR prediction models are confirmed by utilizing a multiple regression method to ensure that the defect of large error of artificially and subjectively confirming the similarity coefficient is overcome; and therefore, the method has the advantages that the evaluation result is more accurate and more reliable and basis is provided for the later economic evaluation of the tight oil block.

The invention discloses a device and method for simulating the hole diameter variation state of a rock core in a tight oil depletion development process. The device comprises a rock core pressure loading unit (1), a rock core holder (2), a rock core data acquisition unit (3) and a nuclear magnetic resonance apparatus (4). According to the invention, by putting the tight oil rock core under the original triaxial stress condition, hole diameter variations caused by changing an effective stress are evaluated jointly on the basis of the nuclear magnetic resonance apparatus and a radial displacement sensor, thereby realizing hole diameter variation measurement based on combined result analysis of a radial displacement test and a nuclear magnetic resonance test; the device and method have the characteristics of high measurement accuracy, strong representativeness, strong operability and the like, and are suitable for popularization and application; and the device and method have important practical meanings for improving the tight oil depletion development level and the oil extraction rate.

Methods are provided to prepare a low sulfur fuel from hydrocarbon sources, such as light tight oil and high sulfur fuel oil, often less desired by conventional refiners, who split crude into a wide range of differing products and may prefer presence of wide ranges (C3 or C5 to C20 or higher) of hydrocarbons. These fuels can be produced by separating feeds into untreated and treated streams, and then recombining them. Such fuels can also be formulated by combinations of light, middle and heavy range constituents in a selected manner as claimed. Not only low in sulfur, the fuels of this invention are also low in nitrogen and essentially metals free. Fuel use applications include on-board large marine transport vessels but also on-shore for large land based combustion gas turbines, boilers, fired heaters and transport vehicles and trains.

The present invention relates to a nano liquid for decompression and augmented injection of tight oil water-flooding, and a preparation method and application thereof. The nano liquid for decompression and augmented injection is composed of 0.1-1% of hydrophobic nano-silica, 0.3-3% of a dispersant, 0.2-1% of a dispersing aid and the balance of water. The hydrophobic nano-silica has particle size between 12-22 nm, and median diameter between 16-18 nm; and the hydrophobic nano-silica is prepared from fumed nano silica and an organic silicon compound by a wet modification method. The dispersant is octylphenyl polyoxyethylene ether, polyethylene glycol 400, polyethylene glycol 600 or glycerin. The dispersing aid is NaOH, Na2SiO3 or n-butanol. The nano liquid for decompression and augmented injection employs water base dispersion and has the advantages of environment-friendliness, simple preparation and good stability. Under the action of stratum water salt ions, the hydrophobic nano-silica is adsorbed on the surface of the rock, so that wetting conversion generates on the rock surface to produce hydrophobic slip effect and reduce flow resistance and injection pressure.