506 results about "Stockwork" patented technology

The invention provides a measuring method for an isothermal adsorption / desorption curve of coaly shale. The measuring method mainly comprises the following steps of: placing a coaly shale specimen into a true triaxial core clamping system; setting an initial measuring state of the specimen according to the actual stratigraphic condition; carrying out an adsorption / desorption experiment on the specimen after the volume of a free pore is calibrated; respectively measuring and recording a cumulative flow value of gas at an inlet end or outlet end and a balanced system pressure value according to a high-precise gas mass flow meter at the inlet end or outlet end and a system pressure sensor; calculating to obtain the volume of the absorbed gas; and then, drawing the isothermal adsorption / desorption curve of the coaly shale specimen. By using the measuring method, influences of a strain field, a temperature field and the like to the adsorption / desorption of gas on the surface of the coaly shale can be truly reflected, experiments carried out under the influence of single factor and experiments carried out under the coupled action of multiple factors can be achieved, and the measured adsorption / desorption curve can be used for truly representing the adsorption / desorption characteristic for gas in an actual coaly shale reservoir.

The invention relates to a debris-core-borehole-reservoir multiscale shale reservoir three-dimensional fracturing evaluation method. The method comprises the steps of: (S1) calculating mineral content brittleness indexes in a shale coring position; (S2) building relations among an internal friction angle, I type and II type fracture toughness and rock mechanical parameters; (S3) building shale fracturing evaluation models comprehensively considering a mineral content, elastic parameters, the internal friction angle, a critical strain energy release rate and the rapture toughness; (S4) applying a support vector machine algorithm to obtain a cluster analysis mode between a reservoir fracturing performance and the elastic parameters; and (S5) applying the cluster analysis mode and a reservoir three-dimensional elastic parameter data body to obtain a debris-core-borehole-reservoir multiscale shale reservoir three-dimensional fracturing model. The method can be applied to obtain the fracturing performance of any space position in a shale reservoir, so that the well position selection blindness is prevented, and the fracturing modification effect and the after-pressing yield are improved.

A method of determining a parameter of interest of reservoir rock formation is described using the steps of measuring an x-ray attenuation or absorption distribution of a sample of said rock formation, identifying the mineral phase part of said distribution, and subdividing the mineral phase part of said distribution to derive classification or rock type information of said sample.

The present invention incorporates the use of geophysical, geological and formation evaluation data to develop synthetic stratigraphic columns based on depositional rules and sedimentary stacking patterns. The present invention utilizes dynamic assignment and matching whereby the synthetic columns can be easily conformed throughout the reservation characterization process as geological data becomes available.

The invention relates to a fast and fine geological orientation method for a shale gas horizontal well. Materials are collected, an orientation comparing standard well and a reference well are determined, and an orientation sign layer and a target spot predicting scheme are determined; a well zone two-dimensional geological orientation model and a well zone three-dimensional geological orientation model are built and regulated, and a two-dimensional vertical section and the three-dimensional geological orientation model of a well to be oriented are amended in time; by means of the characteristics of lithological characters, well deflection, while-drilling gamma and the like of the well to be oriented, the standard well and the reference well, stratum comparing is conducted; the position where a drill is located is judged through three figures, one table and the like; whether the position where the drill is located is in a high-quality shale gas layer section or not is evaluated while drilling; whether an initial geological model is applicable or not is judged; through an equal-thickness comparing method a target spot A is determined and regulated, a target spot B is predicted, and a track of a borehole in a horizontal section is controlled; and the pass-through rate of a high-quality shale gas layer is calculated according to the statistic drilling-meeting thicknesses of a shale reservoir and a high-quality shale reservoir, whether the track is controlled to reach the target spot B or not is judged, and the fast geological orientation effect is evaluated. Fast orientation is achieved, the application range is wide, and application and popularization are easy.

The invention discloses a method used for evaluating shale gas adsorption capacity of shale, and belongs to the field of petroleum, geological and mining exploration and development technologies. The method is capable of calculating the shale gas adsorption capacity of shale reservoirs under the formation temperature, and solving a problem that the cost of existing on-site core analysis technology and adsorption isothermal experiment is high. The method comprises following steps: the contents of organic matter, clay mineral and other minerals of samples collected from different depth of a same shale reservoir are determined; adsorption isothermal experiments of the samples are performed so as to determine the Langmuir volumes of the samples under the formation temperature; an equation set is established based on the contents and the Langmuir volumes of the organic matter, the clay mineral and the other minerals of the shale samples so as to determine the shale gas adsorption capacities of the organic matter, the clay mineral and the other minerals under the formation temperature; and the Langmuir volume of a related depth point is calculated based on the contents of the organic matter, the clay mineral and the other minerals of other depth points.

The invention discloses a method for evaluating the sealing capacity of an oil and gas field reservoir serving as a CO2 storage body at the middle and later periods of oil and gas field exploitation. According to the method, to overcome the defects of the prior art and solve the problems existing in the prior art, based on deep geological research of the storage body, the difference between the reservoir and an overlying strata is considered, a geology evaluating mark set is established and corresponds to log response characteristics, and then the problems existing in CO2 storage evaluation are solved within the oil field spreading range. The method for evaluating the CO2 geological storage body is based on geology evaluating marks and the log response characteristics and comprises the steps of (1) researching various geology evaluating mark parameters of the reservoir and the overlying strata of the geological storage body, (2) establishing the corresponding relation between the geology evaluating marks and the log response characteristics, (3) analyzing the main difference between the reservoir and the overlying strata on lithology and physical property and the cause of the difference, and (4) establishing the technological standard and method for evaluating the CO2 geological storage body of a certain oil field.

The invention relates to the field of geothermal exploitation and provides a single-well fracture gravity self-circulation dry-hot-rock geotherm mining method. According to the method, perforation holes of different depths are utilized, the fracture size of a dry-hot-rock reservoir is increased through a water jet technology and a size fracture technology, and accordingly the upper area and the lower area of the reservoir communicate efficiently through fracture cracks; low-temperature heat-carrying fluid flows to the dry-hot-rock reservoir along the perforation holes in the upper portion after being injected in an annular mode, and then flows to the fracture cracks of the lower area under the actions of displacement pressure and gravity caused by the potential-energy difference of the fracture cracks of the upper portion and the lower portion; and finally, under the action of a ground suction pump, the heated heat-carrying fluid flows back to the ground along the perforation holes in the lower portion via a heat insulating oil pipe. According to the single-well fracture gravity self-circulation dry-hot-rock geotherm mining method, geothermal exploitation is carried out by annular cyclic injection and production of the heat-carrying fluid through the single-well oil pipe, and the expenses for drilling two injection and production wells in the conventional dry-hot-rock geotherm mining process is greatly reduced; and meanwhile, through use of the highly heat insulating oil pipe, the heat loss caused when the heat-carrying fluid is mined out of the oil pipe is reduced, and the heat collection capacity of the heat-carrying fluid is greatly improved.

Systems and methods for improving production from wellbores include providing optimal fracture design parameters based on geomechanical analyses combined with geological, geophysical, and / or petrophysical knowledge. In at least one embodiment, the systems and methods include defining a well direction, defining a fracture spacing, selecting a fracturing fluid system and optimizing a fracture design, such as a complex multi-stage hydraulic fracture design. Such systems and methods can help minimize a learning curve associated with a wellbore or subterranean formation and optimize the hydraulic fracturing operation for a hydrocarbon reservoir.

The invention relates to the field of geothermal exploitation and provides a leakage-proofing process for exploiting a hot-dry-rock geothermal resource by injecting CO2 ( supercritical carbon dioxide). According to the leakage-proofing process, four inorganic salt precipitation generating mechanisms including (1) mixing a high-concentration salt solution with a precipitation inducer; (2) mixing a high-concentration inorganic salt solution with weak-acid / weak-base gas; (3) mixing a high-concentration inorganic salt solution with another high-concentration inorganic salt solution; (4) evaporating and carrying residual stratum water in surrounding rocks by the supercritical CO2 when the supercritical CO2 flows are adopted, the supercritical CO2 is injected into front slugs / rear slugs of a hot-dry-rock reservoir stratum alternatively, the slugs are displaced by the supercritical CO2 till to the position close to surrounding rocks in a leaking area, the solutions in the slugs are mixed to generate certain physical-chemical reactions so as to generate precipitation, and the generated precipitation is used to block off rock pore cracks. By the aid of combination of evaporating and carrying functions of the supercritical CO2, the rock pore cracks are further blocked off by the precipitation. The leakage-proofing process for exploiting the hot-dry-rock geothermal resource by injecting the supercritical CO2 is good in effect after being verified by experiments.

The invention discloses an experimental method of organic acid generation and an erosion effect of the organic acid on a tight oil reservoir. The experimental contents include (1) a hot simulation experiment for proportioning kerogen and a clay mineral to form a sample and generating an organic acid; (2) a hot simulation experiment for generating the organic acid by virtue of thermal evolution of shale; (3) a hot simulation experiment for the erosion effect of the organic acid on tight sandstone and monomineral; and (4) a hot simulation experiment for artificially proportioning the sample. The mechanism and influence factors of the development of the tight reservoir, especially erosion pores of the shale reservoir can be clarified by analyzing the experimental data, and a dynamics model of the organic acid generation and a thermodynamic model of the decarboxylation and erosion reaction of the organic acid can be established; the geological application can be realized by combining the models with the sedimentary and burial history, thermal history and mineral association characteristics of the reservoir in a research area, the development situation of a secondary erosion pore in different geologic periods can be quantitatively evaluated, and a foundation can be set for predicting a tight oil exploration sweet spot area.

The invention discloses a single-layer multi-seam fracturing technology based on a stereoscopic staggered oriented perforating technology, and belongs to the field of oil extraction in low-permeability oilfields. The fracturing technology at least includes the following steps: (1), shaft optimization; (2) optimization of perforation parameters; (3) optimization of oriented perforating manner and construction scale; (4), fracturing construction. According to the invention, the perforation parameters are optimized to guarantee that a single sand body with the reservoir thickness of 30 m is divided into more than four sections after fracturing of separate layers; the stereoscopic staggered oriented perforating construction manner enables the orientations of perforations on adjacent two sections to be different, crack initiation and expansion of cracks at each section are at different orientations, communication of cracks is avoided, construction scale such as sand quantity, discharge and liquid quantity, and fracture scale are improved, and the reservoir reformation volume is increased, so that the discharge volume is enlarged, and well yield is increased; more than four layers of immovable string tools for fracturing of separate layers are adopted for construction, so that fracture of more than four sections can be completed by the pipe column in one trip, and the construction efficiency is improved.

The invention relates to a method for exploiting a geological reservoir which may be a reservoir storing gas (for example CO2). The exploitation (EX) of the geological reservoir is carried out according to an exploitation scheme (SE) defined on the basis of a reservoir model (MR) with the reservoir model being matched (CAL) in relation to dynamic data (DD). According to the invention, the reservoir model (MR) is made representative by a multiple-scale parameterization, with at least two reservoir models (MR1, MR2) that have a different number of mesh cells.

The invention discloses a controllable track lateral drilling tool and method. The controllable track lateral drilling tool comprises a high-passing-ability lateral drilling section and a drilling power transmission section, wherein the high-passing-ability lateral drilling section can achieve drilling of an extending well section of a short-extremely-short-radius well section through the short-extremely-short-radius well section extending from the lateral direction of a main borehole. According to the designed controllable track lateral drilling tool, the borehole can be obliquely drilled at the tail end or any position in the middle of an original borehole track in a short-extremely-radius mode and then extends and is drilled in the lateral direction; and meanwhile, the controllable track lateral drilling tool has engineering feasibility and practical value on thin reservoir development, remaining oil potential tapping, under-salt reservoir horizontal well development, multi-layer system merging development, coal bed gas development, coal mine underground gasification development, unconventional oil and gas development, shallow horizontal well drilling, seabed shallow horizontal well drilling and development of other kinds of minerals.

The invention discloses a deep coal bed gas and dry hot rock type terrestrial heat combined mining method, and belongs to the technical field of geological new energy development. A CO2 injection well is a single-branch horizontal well, a horizontal well section is located in a hot dry rock geothermal reservoir, and 8-10 geothermal exploitation vertical wells are constructed on the ground on the two sides of the horizontal well section; and the CO2 injection well horizontal well section is subjected to staged fracturing and is synchronously fractured with the geothermal exploitation vertical well, so that an artificial fracture channel is formed between the CO2 injection well and the geothermal exploitation well. Lateral drilling of a branch horizontal well is carried out on a straight well section of the CO2 injection well, the lateral drilling horizontal well section is located in the deep coal reservoir, and after drilling is completed, a screen pipe is put down for well completion; and 8-10 coalbed methane mining vertical wells are constructed on the ground on the two sides of the lateral drilling horizontal well section, and a deep coal reservoir is transformed in a fracturing mode after perforation well completion. CO2 is injected into a well for continuous gas injection, the recovery ratio of deep coal bed gas is increased through the replacement and displacement effects of CO2 on CH4, meanwhile, the geothermal energy in the hot dry rock is extracted with supercritical CO2 as a circulating working medium, and the geothermal energy is converted into electric energy through a supercritical CO2 generator.

The invention provides a method and device for quantitatively characterizing wettability of rocks in a shale reservoir. The method comprises the following steps: obtaining shale in the shale reservoir, and preparing a shale sample; performing a spontaneous infiltration experiment on the shale sample to obtain a self-priming slope; calculating a wettability index WI by using WI=(P1-T1)-(P2-T2); performing quantitative characterization evaluation on the wettability performance of the shale sample: the wettability index is within the range of -0.5 to 0; if the wettablity index is closer to -0.5,the water dampness behavior is stronger, otherwise, the shale sample is closer to blended water dampness; when the wettability index is 0, the shale reservoir is in blended dampness; the wettability index is within the range of 0 to 0.5; if the wettability index is closer to 0.5, the oil dampness behavior is stronger, otherwise, the shale sample is closer to blended oil dampness. According to themethod, by introduction of a new wettability index, the wettability of the shale reservoir can be accurately and quantitatively characterized; the method has important significance for designing an effective yield increase technology and estimating the ultimate recovery factor.

Methods and an alarming system for long-term carbon dioxide sequestration in a geologic reservoir are described. The geologic reservoir may be a water filled sandstone reservoir or a carbonate reservoir. A reservoir model is constructed to show the effects of varying injection pressures, the number of injection wells, the arrangement of injection wells, the boundary conditions and sizes of the reservoir on caprock uplift, fracture formation and fracture reactivation. The alarming system generates an alarm when caprock uplift that surpasses a threshold is detected. The injection pressures and the number of injection wells operating may be varied in response to the alarm.

Four or more seismic attributes are integrated or merged into imaging formats and displayed for geological interpretation via extended quantization. Multi-attribute integration and classification improves the ability to identify geologic facies, and reservoir properties such as thickness, fluid type, or fracture intensity and orientation. The extended quantization groups up to eight attributes as a single attribute for geophysical data classification. Data group reduction criteria are provided to reveal common geological targets in the data, while preserving small variations or thin layers often found in hydrocarbon reservoirs. By combining multiple attributes, image quality is enhanced while providing analysts the ability to observe channels that might not be visible in any single attribute.

The invention discloses a rock mechanics and reservoir engineering parameter evaluation method, and belongs to the technical field of rock mechanics. The rock mechanics and reservoir engineering parameter evaluation method comprises the following steps: performing X-ray diffraction on rock debris to obtain mineral components and contents of the rock debris; performing CT scanning on the rock debris, performing observation under a microscope, and obtaining the microstructure characteristics of all mineral particles of the rock debris; carrying out a micro / nano indentation test on the rock debris, and determining the micromechanical parameters of each mineral component of the rock debris; constructing a three-dimensional calculation model according to the rock debris microcosmic characteristic gene, and taking a representative volume unit to obtain rock macromechanics parameters; and evaluating the engineering parameters of the field requirements according to the rock macromechanics parameters and the engineering parameter evaluation model. The rock mechanics and reservoir engineering parameter evaluation method can effectively and accurately obtain engineering parameters required onsite and is of great significance to design and optimization of on-site drilling and fracturing engineering.

Methods for thermalsiphoning supercritical CO2 within a geothermal formation includes providing a geothermal energy system that includes an underground hot rock reservoir, a production well, and an injection well that together form a fluid path suitable for circulating supercritical CO2. The supercritical CO2 flows by thermosiphoning. Thermosiphoning is maximized by maintaining a pressure between 1400-4000 psia, an injection temperature in a range from 50-200 C and a production temperature in a range from 150-600 where injection temperature and the production temperature differ by at least 50° C.

Embodiments of the invention disclose an efficient numerical simulation method and device for an urban scale geothermal field group well system. The method comprises the steps of obtaining geologicaldata of a geothermal field to determine a range of a model calculation area, and building a three-dimensional geological numerical model of a research area according to a geological section map; determining water-heat initial conditions of the model; partitioning heat storage parameters, and distinguishing a heat storage layer and a heat coverage layer; determining water-heat boundary conditions of the whole simulated heat storage system; simplifying geothermal wells into one-dimensional linear geometry, and adding the geothermal well linear geometry into the model according to a distributiondiagram and coordinates of the geothermal wells; setting inflow and outflow boundary conditions of temperatures and fluids for the geothermal wells, and considering a heat exchange process of the fluids in the geothermal wells and surrounding rock masses by adopting an equivalent heat exchange coefficient, wherein the influence of a sleeve pipe and a mortar layer is also contained in the equivalent heat exchange coefficient; and setting a time period function for the model and discretizing each year into two time periods including a heating season and a non-heating season. The difficult problems of grid division and calculation speed of three-dimensional simulation of urban scale geothermal fields can be solved.

The invention discloses a ground stress extending, renovating and yield-increasing method for an oil-gas well. The ground stress extending, renovating and yield-increasing method comprises the following steps: S1, performing a field small crack diagnosis test, wherein geo-mechanical properties of an oil deposit are tested, and the geo-mechanical properties comprise three-dimensional main stress, permeability, reservoir pressure and crack fluid efficiency of a reservoir; S2, controlling injecting pressure to be greater than the smallest main stress of the reservoir and smaller than cracking pressure, adopting a circular hydraulic injection and reflow way at an inlet position, and improving ground stress and pore pressure around the well; S3, changing wellhead injection displacement, adopting an injection and reflow way, generating hydraulic shake in the reservoir to increase a pore volume, expanding micro crack and improving a seepage environment around the well; S4, performing low-sand-ratio injection, carrying silt in a low sand ratio, and supporting a hydraulic renovating region near the well; and S5, braising in the well for several days. The method is simple in process, is relatively low in construction cost, is relatively low in field equipment requirement, and is suitable for a compact sandstone reservoir, a shale reservoir and a reservoir with natural cracks.

A hydrocarbon exploration method is disclosed for developing a model of at least one effective material property of a subsurface reservoir as a function of the composition and structure of the reservoir rock. In one embodiment, the method comprises: obtaining a 3D image (102) of a rock sample characteristic of a reservoir of interest (101); segmenting the 3D image into compositional classes (103) based on similarities in mineralogy, structure and spatial distribution; selecting a model (105) that relates an effective material property of interest to the volume fractions of each compositional class; and determining the parameters of the model (106). The model may be used to assess the commercial potential of the subsurface reservoir (107).

The invention discloses a simulation method for a deblocking process of a heavy oil reservoir based on a digital core model, which is based on an original digital core model containing a plurality ofrock mineral components and a reservoir damage digital core model, combines indoor experimental results (the transformation and volume change law of different types of rock minerals) of the deblockingeffect of a chemical blocking remover to rock minerals and asphaltenes under different simulated conditions, and tightly combines the indoor research result and the digital core model based on the method such as model discrete point stability discrimination and corrosion algorithm in morphology, thereby achieving the simulation of the reservoir deblocking process based on the digital core technology; finally, the deblocking mechanism of the chemical blocking remover to reservoir damage under different simulation conditions is obtained through analysis of the digital core model microstructureand hole penetration change before and after deblocking of the chemical deblocking medicament; and the proposition of the method further expands the application of the digital core technology to oil and gas field development and also provides a new means for the study of the reservoir deblocking process.

The invention belongs to the technical field of uranium mine exploration and particularly relates to a method for predicting an ancient valley uranium reservoir by using old seismic data. At present,the main prospecting means and method are drilling, but investment cost is high, the period is long, and a traditional method is difficult to predict the ancient valley uranium reservoir. The method mainly comprises steps of step 1, determining uranium reservoir attributes by utilizing known uranium mine geological drilling data through a construction criterion, a uranium source criterion, a lithology-lithofacies criterion and a rock geochemistry criterion; 2, combining a petroleum two-dimensional seismic section, carrying out fidelity amplitude preservation processing of anterior seismic data, highlighting the shallow seismic reflection information, analyzing an ancient valley seismic facies of a seismic section passing through a known uranium mine hole, carrying out wave impedance inversion according to known well wave impedance and seismic wave spectrum analysis, realizing shallow interpretation and structure identification of a petroleum seismic section, and determining uranium reservoir attributes; and 3, performing combined verification. The method can be used for predicting the ancient valley uranium reservoir.

The invention discloses a comprehensive evaluation method for a hydration capability of a heterogeneous shale reservoir. The method comprises the following steps: preparing a rock sample according torock of a shale reservoir section, and drying the rock sample to constant weight; measuring porosity and permeability of the rock sample, and obtaining a physical property index of the rock sample according to the porosity and permeability; measuring mineral components of the rock sample, and acquiring a brittleness index of the rock sample according to the mineral components; carrying out a rocksample imbibition experiment test to obtain a hydrophilicity index of the rock sample; and determining a rock sample hydration effect comprehensive index according to the physical property index, thebrittleness index and the hydrophilicity index of the rock sample, and carrying out comprehensive evaluation on a shale rock sample hydration effect capability by adopting the rock sample hydration effect comprehensive index. The method can quantitatively characterize the hydration capability of the shale, the test and application method is simple to operate, a calculation result is more accurate,a large number of mine field experiments are not needed, the economic cost is greatly reduced, and an important scientific basis is provided for optimization of the soaking time of a shale gas well.

The invention provides a dividing method for element phases of a shale section from a five-peak group to a Longmaxi group and a evaluation method for the element phases. The dividing method comprisesthe steps: screening out characteristic elements from shale stratum data in the same block; establishing an element phase division standard according to the relationship between the characteristic elements and the deposition environment; and according to the element phase division standard, carrying out element phase division on each layer section from the five-peak group to the Longmaxi group. The evaluation method can comprise the following steps: carrying out element phase division on each section from the five-peak group to the Longmaxi group by adopting the method, and evaluating reservoir parameters; and according to the evaluation of the reservoir parameters, further realizing the evaluation of the divided element phases. The method has the beneficial effects that the distribution condition of the favorable reservoir can be quickly judged, the quick identification and evaluation work of the shale gas high-quality reservoir can be realized, and the method can play a guiding rolein exploration and development work such as sedimentary paleo-landform recovery, favorable zone optimization, reservoir fracturing transformation and the like.

The invention relates to a rock-like material for simulating reservoir rock heterogeneity and a test piece preparation method, and belongs to the field of rock-like material preparation. The method comprises the following steps: measuring reservoir rock heterogeneity, particle size distribution condition and mechanical parameters; analyzing the influence of the particle size ratio degree on the reservoir rock heterogeneity and the mechanical parameter sensitivity of the rock-like material, and establishing a grading model and a mathematical relationship curve of the rock-like material with different heterogeneity degrees under different particle size ratio conditions by taking the particle size of the quartz sand particles as an index; referring to a fracturing test, and selecting quartz sand particles with corresponding particle sizes to perform aggregate proportioning by using a heterogeneous degree of rock and a rock-like specimen aggregate particle size grading schematic table; preparing a rock-like test piece by taking the quartz sand particles as aggregate, and carrying out maintaining and demolding operation to obtain the rock-like material. The heterogeneous rock-like material provided by the invention can well reflect the control effect of the particle size on the rock heterogeneity, and can accurately describe heterogeneity characteristics of a complex lithologic stratum.

The invention discloses an evaluation method of the mobile oil ratio and the mobile oil source quantity of a low porosity and low permeability sandstone reservoir. The evaluation method comprises thefollowing steps of (A) acquiring oil-gas geology data of a target layer of an evaluation region; (B) performing sampling at different depths of the target layer of the evaluation region to obtain twoor more rock core samples, and determining the porosity and the permeability of each rock core sample; (C) adopting a low porosity and low permeability sandstone reservoir mobile oil ratio evaluationmethod to determine the mobile oil ratio of each rock core sample; (D) according to the porosity, the permeability and the mobile oil ratio of each rock core sample, establishing a relationship formula of the porosity, the permeability and the mobile oil ratio, and calculating the reservoir mobile oil ratio; and (E) calculating the mobile oil source quantity of the target layer of the evaluation region according to the reservoir mobile oil ratio. The mobile oil ratio calculation method provided by the invention does not need to consider a T2 relaxation time cutoff value and is higher in reliability by calculating the mobile oil ratio according to nuclear magnetic resonance T2 spectrum changes of the rock core samples before displacement and after displacement.