235 results about "Clastic rock" patented technology

The invention relates to a determining method for surveying the reserves of hypotonic clastic rock oil-gas reservoir positioned on a clastic rock oil (gas) geological reservoir enrichment boundary, comprising the following steps of: carrying out statistical regression on the daily produced oil-gas data and water data of the traditional testing oil well and the traditional testing gas well and thecorresponding physical data, oil-bearing data and electrical data of an oil layer to determine the physical lower limit value, the oil-bearing lower limit value and the electrical lower limit value of an oil-gas layer, which correspond to industrial oil-gas flows; determining the minimum values of output and a sand body thickness according to the relationship between an effective thickness and test oil output and between the sand body thickness and test production; determining the area boundary of the oil-gas reservoir by using a sandrock thickness isoline method and an effective thickness isoline method; and calculating the reserves of the hypotonic clastic rock oil-gas reservoir. The invention solves the problem that the oil-bearing area of the traditional hypotonic clastic rock oil (gas) reservoir is extrapolated depending on artificial well points, is convenient to apply in the calculation of the reserves, can not only be used for more accurately calculating the reserves of oil (gas) reservoir, but also furthest save the exploration discovery workload and reduce the discovery cost of ton reserves, thereby enhancing the economic benefits of oil-gas exploration and development.

The invention discloses an identification method of the deposition and diagenetic integrated phase of clastic rocks. The method comprises the steps of 1) defining the deposition and diagenetic integrated phase based on a rock core; and 2) identifying the deposition and diagenetic integrated phase by utilizing a logging curve. The invention brings forward the concept of the deposition and diagenetic integrated phase for the first time, and influence of original decomposition and post-stage diagenesis on reservoir physical properties and logging response are taken into consideration; the classification standard of the diagenetic phase in the deposition and diagenetic integrated phase is re-defined, the principle of classifying the diagenetic phase according to the absolute values of compacting, cementing and corroding effects to the reservoir physical properties is provided for the first time, and thus, classification of the diagenetic phase is more accurate; and the logging identification method, in which crossplot identification is carried out on the basis of Bayesian discrimination, of the deposition and diagenetic integrated phase is provided for the first time, and the correct rate of logging identification is obviously improved.

The invention relates to a geophysical oil gas prospecting method which is capable of accurately evaluating targets containing oil gas in clastic rock basin and based on resistivity and induced polarization effect and comprises the specific steps of collecting data from a target area, processing the collected data on time domain and frequency domain, obtaining all-time apparent resistivity and phase curve, drawing a plane anomaly chart of polarization effect, and comparing the chart with the anomaly mode of an oil gas reservoir to determine oil-bearing trap as well as the position border of the oil reservoir and accurately recognize the favorable targets containing oil gas. The invention adopts a high-precision artificial source time frequency deep sounding method for sounding the solid change of electric properties from shallow to deep, including resistivity R and polarizability IP, thus being capable of accurately recognizing the favorable targets containing oil gas and further improving the success ratio of drilling.

The invention discloses a complex lithology natural gas reservoir interval transit time discriminating method, and belongs to the technical field of acoustic logging information application. Formation lithology mineral composition, porosity, water saturation and formation water electrical resistivity factors are utilized to calculate an interval transit time theoretical value curve, the interval transit time theoretical value curve obtained through calculation is compared with an interval transit time curve measured actually, and a natural gas reservoir is discriminated according to the different features of the interval transit time theoretical value curve obtained through the calculation and the interval transit time curve measured actually. The complex lithology natural gas reservoir interval transit time discriminating method is especially suitable for being used in discrimination of natural gas reservoirs of clastic rock, carbonate rock, igneous rock and the like, good in application prospect and capable of improving discriminating effect of the natural gas reservoirs.

The invention discloses an industrial procedure for identifying preferential seepage channels of oil and gas reservoirs of clastic rock. The industrial procedure includes steps of 1), dividing n development phases and dividing wells into n groups according to the development phases of well drilling time; 2), dividing data grids of research areas; 3), interpolating permeability parameters of well points of the well groups 1 to obtain permeability planar distribution grids of the development phases 1; 4), sequentially acquiring permeability planar distribution grids R<1>, R<2>, ..., and R<n> of the n development phases by the aid of a method implemented in the step 3); 5), computing a variation coefficient of a permeability value of each grid point by the aid of results obtained in the step 4) so as to obtain variation coefficient grids P; 6), subtracting the R<1> from the R<n>, assigning values of 1 to the grid points with positive difference values and assigning values of -1 to the grid points with negative difference values to obtain grids T; 7), multiplying the grids P by the grids T to obtain grids Q, drawing contour maps of the grids Q, and utilizing regions larger than 0.3 in the contour maps as the preferential seepage channels. The variation coefficients of the permeability values of the grid points change along with change of the development phases. The industrial procedure has the advantage that oilfield water-flooding development and remaining oil prediction can be guided.

The invention provides a dessert reservoir forecasting method and forecasting device. The method includes the steps: delineating the distribution range of a favorable sedimentary facies belt of a target layer based on ancient landform restoration technology of seismic sequence stratigraphic interpretation; forecasting the spreading range of main channel sand within the distribution range of the favorable sedimentary facies belt based on seismic attribute quantitative analysis technology of forward modeling; forecasting reservoir physical property distribution within the spreading range of the main channel sand based on CRP (common reflection point) gather optimization pre-stack elastic impedance inversion technology. Multiplicity caused by directly forecasting reservoir physical properties by the aid of three-dimensional seismic data in the prior art is reduced, so that low-permeability clastic rock reservoir forecasting accuracy is improved.

Well core data descriptions are received as input digital data for computer lithofacies modeling. Digital templates are established for carbonate and clastic core description based on reservoir rock formation analysis. Description criteria of the template for carbonate rock can include texture, mineral composition, grain size, and pore type. For clastic rock, the criteria in the template can include grain size, sedimentary structure, lithology, and visual porosity. The data and observations regarding these criteria are entered into a computer 3D geological modeling system directly. Wireline log data are integrated to calibrate with well core description to derive lithofacies. The lithofacies are exported in digital format to be entered into the 3D geological modeling system. A geologically realistic model of the reservoir can be established.

The invention discloses a low-permeability clastic rock reservoir effectiveness evaluation method based on a development permeability lower limit, and belongs to the technical field of exploration and development of petroleum and natural gas. The method comprises the following steps: A, calculating an effective development permeability lower limit under the constraints of economic limit primary oil and a development thickness; B, performing evaluation parameter optimization and single scoring based on a permeability difference value; C, computing a weight coefficient and a comprehensive score based on grey correlation analysis; D, performing low-permeability reservoir effectiveness classified evaluation based on an economic primary liquid amount. By adopting the method disclosed by the invention, the key problems of inaccurate computation of a physical property lower limit, difficulty in determining a rational evaluation parameter, uncertainty in a practical classification standard and the like in low-permeability reservoir effectiveness classified evaluation are solved, and the accuracy and practicability of effectiveness classified evaluation of a low-permeability clastic rock reservoir are improved.

The invention relates to a method for using X-ray fluorescence to analyze the extent of porosity of terrigenous clasolite in oil drilling; the method comprises the following steps of: adopting an energy dispersion-typed X-ray fluorescence analyzer to carry out continuous analysis to the chemical elements in the rock core and rock debris in the oil drilling field with the drilling depth; obtaining the analysis data of the X-ray fluorescence changing with the depth; selecting silicon and ferrum elements which have obvious positive and negative relationship with the reservoir property of the rock; using the data of the silicon and ferrum elements to carry out 0-1 normalization data calculation; then calculating the extent of porosity; finally mapping the curve of the extent of porosity; and evaluating the reservoir property according to the curve of the extent of porosity and the value of the extent of porosity. The method of the invention can carry out X-ray fluorescence analysis and the analysis of the extent of porosity of the terrigenous clasolite in real time, use the data of the extent of porosity in real time to carry out quantitative evaluation to the reservoir property of the rock, form a geology explanation and evaluation method with the drilling based on the analysis of the X-ray fluorescence and guide exploration and development practice of oil and natural gas accurately and effectively.

The invention relates to a treatment process of oilfield produced water. The treatment process using two-stage oil-water hydrocyclone separation with backflow as a main part is adopted. The treatment process comprises the steps as follows: firstly, adding a demulsifier to perform demulsification pretreatment; next, carrying out two-stage oil-water hydrocyclone separation; and finally carrying out a deep treatment by combination of air floatation and fiber filtration. After the treatment process provided by the invention is carried out, oil in the oilfield produced water can be recycled, and the produced water meets the Recommended Standard of Water Quality of Hidden Water Injection of Clastic Rocks (SY / T5329-1994) and can be used for water injection in oilfields. The treatment process provided by the invention not only reduces the influence of the oilfield produced water on environment, but also recycles resources.

The invention discloses a reservoir layer evaluation method by utilizing nuclear magnetic resonance logging interpretation parameters, relating to the geology logging interpretation evaluation technology field of petroleum geological exploration; oil saturation So and mobile fluid saturation BVM parameters are chosen, a formula M1=BVM*So is utilized to obtain the M1 parameter which reflects the oil characteristics of the reservoir layer and the total energy; by utilizing the formula SMo=BVM-SMw, the mobile oil saturation SMo parameter is calculated, and then the formula M2=SMO*phi is utilized to obtain the M2 parameter which reflects the recoverable oil volume of the recoverable oil volume, and then the fluid type is determined according to the numeric range of the M1 and M2 values; by adopting the method, different oil grades of the reservoir layer can be effectively and quantitatively divided in a refining way, the undetermined factors of the interpretation parameters caused by block, horizon and oil-containing characteristics are eliminated, and the reservoir layer evaluation method has general applicability to a clastic rock oil-containing bed series.

The invention relates to a Triassic clastic rock petroleum reservoir identification method, which comprises the following steps of: extracting the seismic amplitude of a test object by utilizing seismic data; and performing petroleum-gas prediction on the test object based on the quantitative standard of seismic-amplitude-based petroleum reservoir identification and a seismic amplitude anomaly grading standard by utilizing the seismic amplitude. By the identification method, a productivity ratio can be increased.

The invention discloses underground anti-cracking and impermeable concrete with strength grade no more than C50. The underground anti-cracking and impermeable concrete is mainly prepared from a binding material, clastic rock, sand water and admixture, wherein the binding material is cement, mineral powder and coal ash; the admixture is a water reducer or an anti-cracking and impermeable agent and a water reducer. According to the underground anti-cracking and impermeable concrete prepared by the preparation method, green high-performance concrete is prepared from a lot of mineral powder and coal ashes in a compounding manner; the dosage of the cement for C30-C50 anti-cracking and impermeable concrete is reduced by 30-50% in comparison with that of common concrete, the production cost of the concrete is reduced, and the underground anti-cracking and impermeable concrete plays a protective role on the environment, and has significant economic benefits and social benefits.

The invention provides a method for judging the formation time of fragmental rock based on structural thermal evolution history, which comprises the steps of: firstly, testing a fragmental rock sample by means of fission track to obtain the date of apatite and zircon in the sample; ensuring an analog thermal history route search time region and selecting an analog annealing mode according to the statistics detection probability P (*2) of apatite and zircon; respectively inputting the apatite data, the thermal history route search maximum time region and the annealing mode into thermal history analog software; setting each boundary point in the thermal history route search time region according to the tested track age of the apatite and the zircon and a region construction thermal event; selecting a monte carlo hermal history analog numerical value method; selecting 10000 analog thermal history routes; repeating the analog for 5-8 times; selecting an optimal thermal history route with larger detection values such as GOF and K-S; and analyzing the selected thermal history route to judge the formation time of the sample. The method has low use requirement and wide use range.

The invention discloses a method for evaluating a reservoir stratum with a nuclear magnetic resonance logging interpretation chart, relating to the technical field of evaluation of petroleum geology exploration geological logging interpretation. The method comprises the steps of: selecting two parameters such as an oil saturation So and a movable fluid saturation BVM; obtaining a parameter M1 with the formulation M1=BVM*So; building Phi-M1 interpretation chart; computing the movable oil saturation Smo parameter with the formulation Smo=BVM-Smw; obtaining a parameter M2 with the formulation M2=Smo*phi; building So-M2 interpretation chart; and visually evaluating the classification of the reservoir stratum liquid with the two interpretation charts. The method can solve the problem for evaluating whether the reservoir stratum can generate liquid and the character of the fluid, can solve the problem for evaluating the oil content of the reservoir stratum and the oil capacity, removes uncertain factors of interpretation parameters caused by factors such as block, stratum position and oil content character, and the like, and has universal applicability in oil-containing bed series of clastic rocks.

The invention provides a plugging agent for a clastic rock oil reservoir horizontal well, a preparation method and a water plugging method. The plugging agent comprises the following compositions in parts by weight: 100 parts of crude oil, 0.5-1.5 parts of non-ionic emulsifier, 2-4 parts of anionic surfactant, and 0-40 parts of water, preferably, 20-40 parts of water. The plugging agent provided by the invention is applicable to the clastic rock oil reservoir horizontal well with the formation temperature being less than 120 DEG C and formation water salinity being less than 240000 mg / L. The plugging agent can meet the special shaft condition that ordinary tools cannot be placed and realize water plugging on high water content oil well with special well tracks, and further, the problem that water and oil flow out together in multiple segments of the horizontal well is solved.

The invention relates to a three-dimension fracturing design method for a horizontal well in a compact sandstone reservoir, and belongs to the technical field of oil-gas exploration. The size of an improved sand body of the horizontal well is calculated in combination with sand body distribution in an oil-gas reservoir, three-dimensional earthquake prediction, horizontal well segment oil-gas display, adjacent well physical property parameters and a well network layout, and the length of each segment of the horizontal well, fracture half-length of fracturing and designed sand adding amount in fracturing are determined to achieve the effect that different fracturing design parameters are adopted for different horizontal segments of different types. The pertinence of the fracturing design for the horizontal well is improved, and the whole horizontal segments are improved evenly, so that single well controlled reserves of the horizontal well and the single well yield of an oil-gas well are maximum. The three-dimension fracturing design method is not only suitable for the fracturing design of the unconventional compact sandstone reservoir horizontal well, but also can be used in fracturing design of horizontal well improving in conventional clastic rock reservoir, carbonate reservoir, shale reservoir, volcanic reservoir and the like.

The invention discloses a quantitative prediction method of the clastic rock aquifer water yield property of a working seam roof and floor. The method comprises the following steps of: (1) determining main control factors of the clastic rock aquifer water yield property; (2) determining roof and floor rock stratum disturbance ranges caused by coal seam exploitation; (3) evaluating deposition characteristics of a researched area; (4) carrying out quantitative evaluation on the geological construction complexity degree of the researched area; (5) construction a lithological structure-geological construction prediction model, and comprehensively evaluating the clastic rock aquifer water yield property; and (6) carrying out scientific division and quantitative evaluation on the clastic rock aquifer water yield property. The method provided by the invention overcomes the defect that former people fail to effectively evaluates the clastic rock aquifer water yield property under the condition of deficient hydrogeology data.

The invention discloses a method for sedimentary microfacies logging recognition based on a support vector machine and relates to the technical field of exploration and development. The novel method which is based on an SVM (support vector machine) algorithm and applies logging materials to conduct sedimentary microfacies quantitative recognition is characterized in that each sedimentary microfacies can be represented by a group of logging curve characteristic parameters, samples of a microfacies type are mapped into a higher-dimensional space through nonlinear conversion, and optimal classification faces between each microfacies are sought in the high-dimensional characteristic space; and finally, a decision making function is constructed, so that microfacies types of unknown samples can be determined, and the sedimentary microfacies judgment can be achieved. According to the invention, an SEA technology (sedimentary microfacies automatic recognition method) is used for sedimentary microfacies automatic recognition of a clastic rock reservoir, and judgment accuracy is high; and a reliable judgment basis is provided for optimal selection of beneficial target reservoirs in oil-gas exploration and development, so exploration cost is reduced, and values of application and promotion are high.

The invention relates to a high-resolution exploration method for high-porosity clastic rock sedimentary pile based on transverse wave velocity in geophysical exploration. The method adopts the following steps: the longitudinal wave velocity and the transverse wave velocity of a logged well are intersected with the natural gamma-logging curve of the logged well; the high natural gamma value section and the low natural gamma value section are determined; straight lines are distributed at the intersection point of the high natural gamma value section and the low natural gamma value section, and according to the intercept and the gradient of the straight lines and the intersection points and the inclination angles between the straight lines and the coordinate axis, the relational expression between the longitudinal wave velocity and the transverse wave velocity of the sandstone section and the relational expression between the longitudinal wave velocity and the transverse wave velocity of the mudstone section are obtained; the transverse wave velocity of the high and the low natural gamma value sections is calculated, and the initial model of the longitudinal wave velocity and the initial model of the transverse wave velocity of the seismic working area are built; and wave impedance inversion is performed to the seismic working area by using the initial model of the longitudinal wave velocity and the initial model of the transverse wave velocity and by adopting a conventional method, so as to obtain the ratio of the longitudinal wave velocity to the transverse wave velocity of the seismic working area and to divide the lithologic characters.

The invention discloses a purification method for oilfield reinjection water. According to the method, at least one level of membrane filtration treatment is carried out on oilfield produced water through a cellular carrier type inorganic carbon membrane component so as to prepare the reinjection water suitable for low permeability and extra-low permeability oil reservoirs, wherein the filter precision of the membrane component for membrane filtration treatment is 0.001-100mu m. The purification method has high filtration accuracy, the membrane flux of the compound carbon membrane carrier is large, the capacity of the membrane in resisting oil contamination is strong, the integration level of the structure of the membrane core is high, the quality of the prepared reinjection water is stable, and fine filtrated oilfield reinjection water meets the requirement of the reinjection water for the oil reservoirs in low permeability and extra-low permeability block, and meets the A-grade standard of 'recommended index and analysis method for quality of oil reservoir injection water of clastic rock' (SY / T 5329-94).

The invention provides a method and a system for predicting formation pressure of an exploratory well. The method comprises the following steps: calculating a rock density curve which is not tested bya shallow well logging, splicing the density curve obtained by the well logging and obtaining a density curve rho (d) from a surface to a deep reservoir; Calculating an overlying formation pressure SV (d) and a hydrostatic pressure Phy (d); Calculating formation pressure of shallow clastic rock formation; Calculating formation pressure of gas-bearing shale reservoir; Calculating formation pressure of carbonate reservoir; Based on the results calculated in the above steps, a final pressure predicted logging profile is obtained. By using different pressure prediction models for different lithology, the prediction accuracy of well logging formation pressure can be effectively improved.

The invention provides a seismic attribute guidance horizontal-well-steering method and device. The method comprises the steps that the horizontal-well-steering data for well logging during drilling are obtained; the seismic attributes of the stipulated number of sampling points are extracted longitudinally by taking each point of the track of a horizontal well as the center along each point of the track of the horizontal well, weighted stacking is conducted on the seismic attributes, and the weighted stacking result is used as the seismic attribute of the point; a plurality of seismic attributes sensitive to gamma data are selected preferably combined with the existing horizontal-well-geology-oriented data for well logging during drilling; the gamma data in the data for well logging during drilling and the seismic attributes are used for building a statistics model, and prediction of the gamma data along the track of the horizontal well through the seismic attributes is achieved finally; the lithological characters along the track of the well are judged through the gamma attributes, and guidance for the horizontal well orientation is provided. The seismic attribute guidance horizontal-well-oriented method provides better seismic technology support for geology orientation, improves the drilling catching ratio of the lithological characters of a drilling object, and has good application prospects for horizontal-well-geology-orientation for clastic rocks.

The invention discloses a treating method and process flow for wastewater from an oilfield. Wastewater from oilfield is subjected to pretreatment with an improved three-stage settling tank at first, then to secondary treatment with a three-phase hydrocyclone separation tank, a pressure dissolved air floatation tank and a water purification unit and finally to deep treatment with a filtering unit so as to meet water quality requirements on reinjection water. The process flow can overcome the problem that wastewater from the oilfield is high in oil content, sulfur content, iron content, bacteria content and mineralization, enables treated wastewater to meet standard requirements on water quality prescribed in Indexes and Analysis Methods for the Quality of Injection Water for Clastic Rock Reservoirs, and has the characteristics of stable water treatment, high recovery rate of oilfield water, environmental protection and accordance with standards.

The invention relates to an oil extraction sewage depth-processing method, and relates to a sewage processing process. The invention resolves the problems of the multi-level precise-filter method in the prior art that the produced water quality is unstable, the flux of the pure hyper-filtration method film is rather low, the cleaning is frequent and the sewage processing cost is high. The method comprises the following steps: pre-treating, micro-filtration treating and cycling hyper-filtration film depth treating. The invention adopts the method integrating the conventional craftwork and the integrated film craftwork to effectively improve the flux of the hyper-filtration film, to prolong the film running period and to reduce the sewage processing cost. The sewage after being processed with the method can reach the A1-level water-injection standard in Recommended Index and Analysis Method for the Water Quality Injected in Clastic Rock Reservoirs (SY / T5329-94).

The invention discloses a method for identifying lithological characters of sedimentary rocks by utilizing element logging. The method consists of the following steps: a, processing element logging data and converting the element logging data into percentage content; b, by utilizing percentage of content of a clastic sensitive element and a carbonate sensitive element, distinguishing two types of rocks of a carbonate rock and a clastic rock; c, in the carbonate rock type, calculating calcium sulfate content, magnesium calcium carbonate content and calcium carbonate content; d, in the clastic rock type, calculating sand content and shale content; e, carrying out normalization processing on the calculated content of calcium sulfate, magnesium calcium carbonate, calcium carbonate, sand and shale to respectively calculate content of gypsum, dolomite, lime, sand and shale so as to determine the lithological characters according to the content of gypsum, dolomite, lime, sand and shale. According to the method disclosed by the invention, the element logging measured data is used as parameters, and a set of lithological character identification model is established by analyzing chemical ingredients and rock forming principles of various lithological characters, so that the effect of distinguishing the lithological characters while drilling of element logging is realized.

The invention discloses a drainage construction method for a tunnel passing through a clastic rock steeply inclined reverse thrust water-rich fault. The drainage construction method is characterized in that a construction tunnel main cave is divided into a rear side tunnel section, a front side tunnel section and a middle portion tunnel section passing through the clastic rock steeply inclined reverse thrust water-rich fault, wherein a by-pass pilot tunnel and a drain cavern are formed in the same side of the construction tunnel main cave. When drainage construction is carried out in the construction tunnel main cave, the drainage construction method comprises the steps of: 1, carrying out preliminary excavation construction on the rear side tunnel section; 2, synchronously carrying out excavation construction on the rear side tunnel section and a drainage hole body of the drain cavern; 3, synchronously carrying out excavation construction on the rear side tunnel section, the drainagehole body of the drain cavern and a rear side by-pass pilot tunnel section; 4, and carrying out construction on the front portion drainage hole body, and synchronously carrying out construction on theby-pass pilot tunnel and the tunnel main cave. The drainage construction method provides a new construction working plane by means of the by-pass pilot tunnel, improves the working efficiency, provides the high-altitude drainage hole between the tunnel main cave and the by-pass pilot tunnel, can drain water embedded in the fault to the greatest extent, reduces water pressure in the fault in frontof a tunnel face, ensures safety construction of each tunnel face and can shorten the construction period.

The invention relates to a method for determining a relative content of a clay mineral in a clastic rock and a filling. The method comprises the following steps: firstly, identifying the clay mineral and plastic rock debris among sandstones according to a rock slice identification standard of the petroleum and natural gas industry standard SY / T5368-2000; analyzing the relative percentage contents of various clay minerals according to the relative content of the clay mineral in sedimentary rock in the standard SY / T5163-1995; respectively obtaining absolute percentage contents of the clay mineral in the clastic rock, the filling and a mud matrix, obtaining the absolute contents of the plastic rock debris and the mud matrix kaolinite in the clastic rock, and respectively obtaining the total weight of kaolinite in the rock clay mineral and the relative content of the kaolinite in the filling; finally, obtaining the relative content of the clay mineral of the clastic rock above that of the filling. The method can help accurately determine the relative content of the clay mineral in the clastic rock and the filling, and correctly evaluate sensitivity property of reservoir beds.

The invention specifically relates to a temporarily plugging / shielding protection agent and a preparation method thereof, belonging to the field of temporary plugging agents for energy exploitation. The temporarily plugging / shielding protection agent is prepared by successively coating organic acid solid particles with ethyl cellulose, which is mixed with a pore-foaming agent, at first and then with a protective agent next. The temporarily plugging / shielding protection agent provided by the invention is applied to the development of oil and natural gas in tight clastic rock reservoirs, and ismainly used for reservoir protection during fracturing completion. The temporarily plugging / shielding protection agent is used in the process of fracturing to form a temporarily plugging / shielding zone under the action of pressure difference so as to reduce fracturing fluid loss and prevent fracturing fluids from entering strata; in a later phase, a coated material is slowly dissolved and releasedthrough micropores, which is beneficial for gel breaking and flowing back of fracturing fluids; after the coated material, i.e., a gel breaker, is dissolved and released, a flexible coating becomes ahollow flexible shell, so the flexible coating is not supportive and is thus peeled off from a temporarily plugged surface and discharged back together with the gel-broken fracturing fluid; and aftercompletion of construction, no residue is left in the strata, so reservoir damage is reduced.