90 results about "Residual oil saturation" patented technology

The invention discloses a method for quantitatively evaluating influence of water injection on distribution of pore throats. The method comprises the following steps: taking rock core for experiment, scrubbing oil and drying, measuring porosity and gasometry permeability of the rock core and calculating pore volume; preparing formation water salinity of simulated formation water for experiment; preparing oil field crude oil viscosity of experiment simulated oil; saturating the rock core and simulating the formation water, and measuring a nuclear magnetic resonance T2 spectrum; displacing the rock core of the saturated and simulated formation water by using prepared and simulated oil and recording original oiliness saturation and recording initial oil saturation; selecting a simulated formation water displacing speed according to the rock core permeability, simulating formation temperature and pressure, displacing the rock core of the saturated oil by using the simulated formation water and enabling the rock core to achieve residual oil saturation; scrubbing oil and drying the rock core, then saturating the simulated formation water and measuring a nuclear magnetic resonance T '2 spectrum; respectively drawing a distribution curve graph of the nuclear magnetic resonance spectrums before and after driving water, quantifying to obtain the degrees of influence of different water drives on the distribution of the pore throats. The method is capable of testing online, thereby realizing the quantitative evaluation on the degree of influence of water injection on the distribution of the pore throats.

The invention relates to a method for predicting the water cut increasing rate of a water-drive oil field. The method includes the following steps that cylindrical rock samples are taken from a natural rock core of the oil field, a rock core displacement experiment is performed, and a series of parameters such as water saturation Sw, oil phase relative permeability Kro and water phase relative permeability Krw are obtained; irreducible water saturation Swi and residual oil saturation Sor are obtained, and the oil and water viscosity ratio mur is obtained through measurement; the relations between the oil and water relative permeability ratio and the water saturation, the reflected relational expression between the water content and the recovery percentage, and the relational expression between the water cut increasing rate and the recovery percentage are obtained with a power method. According to the method, oil and water relative permeability materials are utilized, a power type mathematical processing method is adopted, the water content and the water cut increasing rate of the oil field are described, the development effect and the development degree of the oil field are analyzed and evaluated, development measures are planned according to the method, the yield of the oil field is reasonably planned and deployed, and more effective guidance can be provided for development of the oil field.

The invention is a method for multi-well cyclic steam stimulation thickened oil recovery by thermal recovery-steam injection technique, selecting: oil-layer depth in oil reservoir<1800m, residual oil saturation > 0.40, total oil-layer thickness > 5.0m, net-total thickness ratio >0.4, oil-layer porosity >0.15, and permeation rate variation coefficient <0.8; placing adjacent steam channeling wells and steam channeled wells (above two) together in the same group, simultaneously making steam injection in the well drainage sequence or block cluster well sequence, where steam injection strength of single well is 50-200 cu m/m and the well-bottom dryness fraction is greater than 50%, then stewing them, and finally opening them for production in the same sequence as above-mentioned. It can prevent steam channeling and interference between wells, effectively supplements pressure energy to oil layers and helps enlarge the steam spread range, and can increase the oil-layer pressure by about 2MPa as compared with single well steam stimulation method. It can both increase single-well output and prolong the life of steam stimulation.

The invention relates to a method for improving recovery rate of a thick massive viscous oil reservoir by controlling burning gas injection speed, which mainly comprises the following steps of: determining the thickness and residual oil saturation of an oil layer at the burning front edge by stages according to the condition and rule of fire-flooding live wire wave by combining fine research results of double analogs in a massive oil reservoir chamber; then determining planar residual oil saturation and residual oil at different positions apart from a gas injection well, and predicting the burned section area of the burning front edge, the non-homogeneity of the reservoir and the optimal configuration relationship between the residual oil and the gas injection speed; and finally, dynamically adjusting the single-well gas injection speed by stages, and selecting a variable and lower burning gas injection speed to maintain stable and normal burning on the premise of ensuring combustion. The method can fulfill the purposes of improving the burning wave and volume of the massive oil reservoir, the development effect of the burning oil layer and the final recovery rate.

The invention provides a method for representing an oil-water relative permeability curve under the condition of different driving displacement pressure gradients, and belongs to the technical field of reservoir engineering in oil development. The method comprises the following steps that (1) different driving displacement pressure gradients are exerted on a group of rock cores with identical or similar permeability to obtain the relative permeability experiment data of each rock core, then, a permeability curve corresponding to each rock core is made according to the relative permeability experiment data, and next, the relative permeability curve corresponding to each rock core is subjected to normalization processing to obtain an oil-water relative permeability curve corresponding to each rock core; (2) the statistical laws on the water phase maximum relative permeability, the oil displacement efficiency and the pressure gradient are fit out according to the relative permeability experiment data, and the water phase maximum relative permeability and the residue oil saturation degree under different pressure gradients can be solved; (3) a characteristic curve equation of the relative permeability curve corresponding to each rock core is solved.

The exploration and development of unconventional oil-gas reservoirs, especially the dense gas-oil reservoir, has become a bright spot of the oil exploration and development in recent years and a mainbattlefield of the future oil exploration and development. The wettability is one of important parameters for knowing dense oil-gas reservoir characteristics, and an operation of effectively determining the rock wettability has important significance for researching recovery percent of the oil reservoir, an oil-water ratio after water channeling, recovery ratio improvement and residual oil saturation. The invention discloses a new method for dense rock wettability determination, the disadvantages that the traditional self-absorption metering is inaccurate and nuclear magnetic resonance oil-water signals are hard to distinguish are overcome, a nuclear magnetic signal of the water is shielded by effectively utilizing manganese chloride, the self-water-absorbing oil discharge amount, water-driving oil amount, self-oil-absorbing water discharge amount and oil-driving water amount are accurately acquired by combining T2 spectral curve of the rock and weighing and weight change characteristics thereof, and the effective determination of the dense rock wettability is realized. The new method disclosed by the invention has the advantages of being small in current personal factor influence, high in data reliability, and simple and convenient.

The invention investigates the effects of reservoir heterogeneity on IPR curves for horizontal wells drilled in heterogeneous solution gas drive reservoirs. To achieve the desired objective, a commercial simulator Eclipse is utilized to develop IPRs for horizontal wells producing oil from solution gas drive reservoirs. Firstly, a simulation model is developed where a base case is considered with typical rock, fluid and reservoir properties using a black oil model. Dimensionless IPR curves are generated by obtaining a set of points relating to flowing bottom-hole pressures to oil production rates. The effects of several reservoir and fluid properties such as bubblepoint pressure, oil gravity, residual oil saturation, critical gas saturation, initial water saturation, porosity and absolute permeabilities on the calculated curves are investigated.

Reservoir heterogeneity is included in the simulation model by incorporating a semi-variogram function. Finally, a new single empirical IPR model is obtained for horizontal wells producing oil from heterogeneous solution gas drive reservoirs suitable for systems with different reservoir permeability. The new empirical IPR model is then compared to published correlations and is found to have a small and acceptable average absolute error of less than 2%. Furthermore, the invention also shows that bubble point pressure has significant effect on dimensionless IPR curves. However, plots for other properties indicate that although the curves are not identical, they are similar in shape and demonstrate much less variance than the bubble point pressure plot. Therefore, these properties have only a minor effect on calculated, dimensionless IPR curves.

The invention provides a method for determining residual oil saturation of a non-uniform water flooded layer, and belongs to the technical field of geophysical logging evaluation of reservoir saturation. A non-uniform water flooded layer saturation equivalent model diagram is established by an equivalent area method, and a method for determining residual oil saturation by production profile data is corrected to obtain the method for determining the residual oil saturation of the non-uniform water flooded layer; the obtained residual oil saturation of the non-uniform water flooded layer better reflects the overall residual oil saturation of the water flooded layer, and is more consistent with the actual situation of a reservoir, thus achieving accurate knowledge of the regional residual oil saturation distribution law, and providing a scientific basis for reasonable and efficient development of the reservoir.

The invention relates to a calibration method for an oil-water relative permeability curve and an oil displacing efficiency. The calibration method comprises the following steps: 1), performing an indoor oil-water relative permeability experiment, combining basic parameters of the experiment so as to obtain experimental data of a water ratio, cumulative oil yield, cumulative water yield and the like at different sampling times, and drawing an oil-water relative permeability curve before calibration; 2), fitting the cumulative oil yield and the cumulative water yield by adopting a Zhang type water driving curve with wide adaptability, and solving recoverable reserves; 3), plugging the recoverable reserves and the basic parameters of the experiment into an expression of residual oil saturation, and solving the residual oil saturation; 4), according to the residual oil saturation and an exponential expression of a water phase relative permeability curve in the straight line form, solving water phase relative permeability corresponding to the residual oil saturation; 5), replacing the residual oil saturation and the water phase relative permeability corresponding to the residual oil saturation in the oil-water relative permeability curve before the calibration with the solved residual oil saturation and the solved water phase relative permeability corresponding to the solved residual oil saturation, so that an oil-water relative permeability curve after calibration is obtained; and 6), calibrating the oil displacing efficiency according to the solved residual oil saturation.

The invention provides a method for increasing the recovery ratio of thick oil. The method comprises the following specific steps of: injecting a steam injection string; connecting a ground steam injection pipeline with a subcritical steam-water two-phase flow meter, scanning the steam injection pipeline, testing the pressure of a well mouth and judging the pressure to be qualified if no pressure leaks after three minutes; inversely injecting a casing pipe; injecting steam into an oil pipe; after the steam is injected, mounting a temperature-resistant pressure gauge at the well mouth and starting to soak the well; and spraying by using an oil nozzle. Due to the utilization of gas, chemical and heat energy and actions of three substances, the mixed mass transfer action of the three substances in the longitudinal and transverse actions of an oil layer are exerted, the production pressure difference is reduced, the flowability of crude oil is improved, the oil-displacement power is increased, steam waves and the radius are increased, the saturation of residual oil is reduced and the aims of increasing the recovery ratio and improving the development effect are finally achieved.

The invention provides a method for determining the productivity of new wells in an old area of an offshore oilfield based on multiple factors. The method includes the steps that the new well production effective thickness is designed; according to the residual oil saturation and the water content in production of corresponding layers of adjacent old wells in combination with the relation between the water content in the initial stage of production of new wells of an adjusted block and the water content of the surrounding old wells with similar oil reservoir conditions, the water content in the initial stage of production of the new wells of the block is determined; according to oil reservoir oil-water phase permeability data, the changing curve of the non-dimensional oil production index along with the water content is calculated, and the oil production index under the water content is calculated; the initial-stage production pressure difference of the new wells is determined; the theoretical daily oil productivity of the new wells is calculated; the relation between the actual yield and the theoretical calculated yield is summarized to determine the actual daily oil productivity in production of the new wells of the block. By means of the method for determining the productivity of the new wells in the old area of the offshore oilfield based on multiple factors, the purpose of improving the accuracy of prediction of the productivity of the new wells in the old area of the offshore oilfield is achieved, and meanwhile a basis is provided for offshore productivity planning and smooth new well drilling.

The invention discloses electromagnetic drive underground high-power resonant wave displacement device and method. The displacement device comprises a ground vibration source, an artificial well bottom and an underground vibrator, wherein the ground vibration source is distributed at the right upper part of a well opening of a vibration source well; the artificial well bottom is distributed at the well bottom of the vibration source well; the underground vibrator is vertically inserted into the vibration source well from top to bottom; the ground vibration source is an electromagnetic vibrator which drives the underground vibrator to vibrate up and down; and a front rope end of a steel rope is fixed to the upper end part of the underground vibrator after penetrating through a central through hole of the ground vibration source from top to bottom, and the steel rope is tightly connected with the ground vibration source. The displacement method comprises the following steps of: 1. selecting the vibration source well; 2. positioning equipment; 3. adjusting a working parameter of the ground vibration source; and 4. carrying out underground vibration displacement by adopting a resonantwave. The invention has the advantages of reasonable design and good construction effect, is convenient for installation and distribution and simple and convenient for use and operation, directly converts electric energy into vibration mechanical energy with stable frequency and stable energy by utilizing an electromagnetic device and greatly improves crude oil yield when reducing the saturation of residual oil.

The invention discloses a method for determining reservoir water saturation, which comprises the following steps of: obtaining the porosity and permeability of a rock core, and establishing a porosity-permeability calculation model by combining acoustic logging data; Obtaining a saturation index n value, and establishing a reservoir resistivity calculation model when the water content is 100%; Respectively establishing a calculation model of irreducible water saturation and residual oil saturation; Determining the resistivity of the original formation water and the resistivity of the slurry filtrate of the oil reservoir by utilizing test analysis, and determining the resistivity of a pure oil layer by irreducible water saturation, residual oil saturation, resistivity of a flushing zone anda saturation index; And establishing a new reservoir water saturation calculation model, and calculating the reservoir water saturation through the reservoir measurement resistivity, the reservoir resistivity when the water content is 100%, the pure oil layer resistivity and the irreducible water saturation. According to the method, the water saturation of the reservoir stratum is solved point bypoint through logging data without depending on an alpha formula under the condition that formation water resistivity of different stratum sections of the stratum is unknown, and a new method is provided for accurately solving the water saturation of the reservoir stratum.

The invention relates to the technical field of rock core oil washing effect evaluation, and in particular relates to a method for quantitatively evaluating the oil washing effect of a rock core by using a nuclear magnetic resonance (NMR) technology. The method comprises the following steps: (1) volatilizing an oil washing solvent and drying; (2) measuring gas porosity and gas void volume; (3) measuring the NMR T2 spectrum of the rock core and the NMR T2 spectrum of a standard sample; (4) obtaining residual oil volume; (5) obtaining residual oil porosity; and (6) obtaining residual oil saturation, thereby evaluating the oil washing effect of the rock core. According to the method, the time of a measurement process is short, and the efficiency of measurement is effectively improved; during measurement, the measurement is non-contact and non-destructive measurement, no damage to the rock core can be caused, and the measured rock core cannot affect the subsequent experiment measurement of the rock core; meanwhile, quantitative parameters, such as the porosity of the rock core, the residual oil volume, the residual oil porosity, the residual oil saturation and the NMR T2 spectrum of residual oil, can be simultaneously obtained, so that the applicable range is wide.

The invention discloses a water displacing oil relative permeability time varying rule representation method based on ternary dynamic parameters. The water displacing oil relative permeability time varying rule representation method comprises the following steps: a stable production stage is divided; the stage is subjected to progressively-decreasing analysis; an endpoint value and a shape of a relative permeability curve are determined; the relationship between the saturability of residual oil and the accumulated water displacing intensity under different instantaneous water displacing intensity is regressed; the relationship between the water phase relative permeability and the instantaneous water displacing intensity under the residual oil is regressed; the relationship between an oil phase index m and the accumulated water displacing intensity, the relationship between the oil phase index m and the instantaneous water displacing intensity, the relationship between a water phase index n and the accumulated water displacing intensity, as well as the relationship between the water phase index n and the instantaneous water displacing intensity are regressed; and a ternary dynamic parameter water displacing oil relative permeability time varying rule representation general formula based on the effective wetting phase saturability, the accumulated water displacing intensity and the instantaneous water displacing intensity is obtained in a simultaneous mode. Through actual production effect inspection, it is proved that through the water displacing oil relative permeability time varying rule representation method, the development history fitting precision of medium and high seepage water displacing sandstone oil reservoirs and the residual oil saturability distribution prediction precision can be improved significantly, thus the prediction accuracy of a production dynamic indicator change trend is improved, and high universality is achieved.

The invention relates to a method for simulating and evaluating an oil production scheme by adopting a digital rock core. The method comprises the following steps: scanning a rock core sample so as to obtain two-dimensional images of cross sections of the rock core sample; performing three-dimensional reconstruction on the two-dimensional images of the cross sections of the rock core sample, and reading parameters characterizing the porous media of a rock core; setting initial conditions according to the parameters characterizing the porous media of the rock core, and performing numerical simulation of an oil production rock core displacement experiment by adopting a Boltzmann lattice method according to the initial conditions, wherein displacement liquid is injected into the porous media of the rock core; and calculating the oil production and water production according to the numerical simulation, and simulating a curve of the saturation degree of residual oil along the change of the injection volume of the displacement liquid, and selecting the oil production scheme according to the oil production, water production and curve. The oil production effect can be accurately and fast quantitatively evaluated by using the method for simulating and evaluating the oil production scheme by adopting the digital rock core.

The invention belongs to the technical field of petroleum exploration and development, in particular to an oil and gas reservoir recognition method applied to qualitatively analyzing existence of oil reservoirs through detection data, and provides a method of judging a low-resistivity annulus formed in a formation. The method includes: acquiring core data and determining irreducible water saturation Swb and residual oil saturation Sor of a core; acquiring a ratio of drilling fluid resistivity Rmf and formation water resistivity Rw according to the irreducible water saturation Swb and residual oil saturation Sor of the core; detecting a target formation to acquire the formation water resistivity Rw and the drilling fluid resistivity Rmf; if an actual physical value is larger than a calculated value, determining the low-resistivity annulus is formed. Through the application of the method in low-resistivity oil and gas fields, efficiency of exploiting low-resistivity oil and gas reservoirs can be improved effectively, the low-resistivity oil and gas reservoirs are recognized visually and quickly, exploration cost is reduced, and economic benefit is increased. As China possesses many low-resistivity oil and gas reservoirs, the method has promising application prospect.

The invention discloses a method and a system for calculating the saturation of residual oil corresponding to a water flooding level water flooding layer. According to the method, ion exchange rate parameters are introduced according to different ion exchange amounts of injection water at different water injection stages and undisturbed formation water; and meanwhile, the water saturation, water yield, oil phase relative permeability and water phase relative permeability at different moments are calculated from initial conditions, and a new water flooding layer interpretation model is deducedand can adapt to the residual oil saturation calculation of water flooding layers of different water flooding levels. By means of the method and the system, the problem of residual oil saturation evaluation at different water flooding levels can be solved, the residual oil saturation can be accurately calculated, and scientific basis is provided for oil field development scheme adjusting, water control and oil stabilizing, as well as old well excavation. The method and the system have high popularization value and economic benefit.

The invention provides a chelating augmented injection agent for a water injection well and a preparation method of the chelating augmented injection agent. The chelating augmented injection agent isprepared from the following raw materials in percentage by mass: 26%-35% of an amino cartankylic acid chelating agent, 10%-14% of a penetrating agent, 12%-16% of an ampholytic surfactant, 14%-18% of anonionic surfactant, 18%-22% of a mutual solvent and the balance of water. The chelating augmented injection agent for the water injection well can be used for treating water injection wells with poor injection water quality, stratum scaling and high residual oil saturation and water injection wells with long-term produced water reinjection, resulting in high water injection pressure and seriousunder-injection of the water injection wells or long-term water injection under-injection wells. The crude oil stripped from the rock surface is dispersed into small oil drops under the action of thesurfactant, and the flowing capacity of the crude oil passing through the throat is improved, so that the reservoir permeability is improved, the stratum is dredged, the oil well liquid supply capacity is recovered, and normal water injection of a water well is realized.

The water displaced steam injecting hot masout exploiting method is used for further explitation of water displaced masout deposit to raise the exploiting rate. The water displaced masout deposit is converted into hot steam soak and hot steam displacement through the steps of: selecting masout deposit with oil layer depth smaller than 3000 m, residual oil saturation degree greater than 0.30, oil depth thickness greater than 5.0 m, net total thickness ratio greater than 0.3, oil layer porosity greater than 0.15 and permedbility variation coefficient smaller than 0.8; selecting reversed nine-point well network and drilling new steam injecting well apart from production well by 150-300 m for steam injecting hot exploitation; and converting into steam displacement of simultaneous steam injection and continuous production with single well steam injection speed of 1.0-3.0 cu m/d. ha m, well bottom steam quality greater than 30 % and injection-production ratio manufactured over 1.0. The present invention raises recovery ratio by over 10 %.

A method for measuring the saturability of residual petroleum with single oil well chemical tracer includes such steps as injecting the first original tracer as segment blocking solution in oil bearing stratum, injecting methanol or butanol to displace tracer to form the segment blocking of stratum salt's aqueous solution, injecting the second original tracer to form the second segment blocking, driving the first segment blocking to the oil bearing stratum far from oil well, closing the well and stop flowing, recovering oil, recording the relation curve between the concentration of tracer and output liquid scaling the stay volume in well, scaling the effective injected volumes for both injection, finding the recovering cross-section of the first tracer, and calculating the saturability of residual oil.