GB2607465A - Analysis system and method for designing and correcting water curtain system of underground water-sealed oil storage - Google Patents
Analysis system and method for designing and correcting water curtain system of underground water-sealed oil storage Download PDFInfo
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Abstract
An analysis system and method for designing and correcting a water curtain system of an underground water-sealed oil storage, providing a method basis for design, construction and operation of the water curtain system of the underground water-sealed oil storage, combining geological exploration data and existing related research cases, and obtaining related parameter data required by the solution in an indoor test. The specific parameter selection range of the water curtain system is rapidly and accurately reduced by means of a finite element analysis method, the final design and construction solution is determined, accuracy and time saving are achieved, feasibility is high, and the oil leakage rate is low.
Description
ANALYSIS SYSTEM AND METHOD FOR DESIGNING AND CORRECTING WATER CURTAIN SYSTEM OF GROUNDWATER SEALED OIL STORAGE RESERVOIR
TECHNICAL FIELD
The present disclosure belongs to the research field of underground oil storage reservoirs, and relates to an analysis system and method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir.
BACKGROUND
The statements in this section merely provide the background art information related to the present disclosure, and do not necessarily constitute the prior art.
Strategic oil reserve is the first line of defense against the crisis of oil supply shortage, and is an important link to ensure national defense security and economic security in China. In recent years, with the progress of the national oil reserve project, a large number of oil reservoirs have been established one after another. Groundwater sealed oil storage reservoirs are more and more widely used due to the advantages of high safety factor, less floor space, less pollution, less infrastructure investment, low operation and management costs and fast loading and unloading. The groundwater sealed oil storage reservoir refers to the technology of building unlined oil storage caverns in areas with a certain depth below the stable groundwater level and with good rock mass stability, and storing oil products by virtue of the action of water pressure.
A water curtain system is the key to determine the operation of a groundwater sealed cavern reservoir. However, the design concept and method of the water curtain system are still immature, and most of the design is based on the relevant parameters of the foreign completed projects for self-design. Due to the lack of completed reference cases, it is difficult to find similar reference cases in terms of hydrogeological conditions, oil reservoir scale, stores and lithology. After completion, the relevant design parameters still need to be adjusted according to the conditions of trial operation, and effective means and methods are still needed to guide the design.
For the completed projects, how to achieve high-efficiency, low-cost and safe operation is another problem that will be faced in the future. The current application method is to bury seepage pressure sensors at a certain depth underground to monitor the seepage pressure at the corresponding positions in real time for a long term However, in the face of anomalies caused by special weather or changes in surrounding rock properties, it is still difficult to make early warning and remedial measures resulting in higher cost waste and even oil leakage.
SUMMARY
In order to solve the above problems, the present disclosure provides an analysis system and method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir. The present disclosure can effectively solve the problems of poor feasibility of design parameters of water curtain systems and high operation cost, and provides a reference for the design and operation of underground oil storage reservoirs.
According to some embodiments, the following technical solutions are adopted in the present disclosure: An analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir includes: (1) collecting rock samples in a reservoir site area, and performing a triaxial compression test and a shear seepage coupling test on a structural plane, so as to obtain rock mechanical parameters and structural plane related parameters; (2) preliminarily designing the water curtain system according to hydrogeological and engineering geological investigation reports as well as the rock mechanical parameters obtained by tests and calculations by using an engineering analogy method and referring to the reference cases of the completed projects at home and abroad, and giving an approximate parameter range, including a hole distribution mode of water curtain holes, a length of the water curtain holes, a distance between the water curtain holes, a number of the water curtain holes, a height difference between the water curtain holes and an oil storage cavern, and a water curtain pressure; (3) performing finite element analysis, establishing a plurality of multi-physical field coupling simulation models based on the obtained parameter data and geological data as well as the conditions of a pressure seepage field of the reservoir site area, and performing analog calculations of a plurality of proposed design parameters of the water curtain system; (4) judging the feasibility of the calculated water curtain parameters based on the validity judgment basis-vertical hydraulic gradient criterion, where if a certain parameter range is not feasible at all, it means that the selected parameter range has a larger deviation from the actual needs and the previous case cannot be referenced; returning to step (2), and selecting a range again until a final construction scheme is determined; (5) after completion, continuing to monitor the seepage pressure around the oil storage reservoir for a period of time, and collecting time series monitoring values to detect the state of the oil reservoir during an operation period; (6) linearly predicting the collected time series data, establishing a reasonable estimation formula by an exponential smoothing method, predicting the change trend of the seepage pressure in the future, comparing a predicted result with an actual value measured later, and verifying the predicted result; and (7) adjusting the parameters of the water curtain system in real time with reference to the hydrological monitoring data during a construction period and the operation period and the predicted data during the operation period in the future.
As an optional implementation, in step (I), the selected rock mechanical parameters include hardness, density, surface roughness, elastic modulus, Poisson's ratio, joint shear stiffness and hydraulic opening; the mechanical parameters are obtained by testing random-shaped rock blocks excavated by a blasting method, where the hardness is quickly measured by a Schmidt rebound apparatus; the density is quickly calculated according to the mass and volume of the rock blocks; the surface roughness is obtained by measuring cylindrical samples prepared from the rock samples by a roughness meter; the elastic modulus and the Poisson's ratio are obtained by a rock indoor triaxial test carried out by an RLW-500 type rock triaxial apparatus; and the joint shear stiffness and the hydraulic opening are calculated by a shear seepage coupling test on an indoor stntctural plane.
As an optional implementation, in step (1), the triaxial compression test and the test of each of the rock mechanical parameters are performed according to the national standard GB/T 50266-2013.
As an optional implementation, in step (3), the finite element analysis needs to consider boundary conditions and initial conditions, and finally determine the distribution of water heads by solving differential equations; the analog calculation of a seepage field refers to 1 0(p+ yuz) v = k Darcy-Weisbach Formula. where k represents a medium permeability coefficient; y represents a weight density of water; p represents a pore water pressure; vi represents a flow rate of groundwater seepage; z represents a vertical coordinate; and xr represents a distance along an x direction.
As an optional implementation, in step (3), the sizes of the established multi-physical field coupling simulation models are all based on the construction design, and medium parameters and physical field applications are set according to the investigation reports; the surrounding rock in the reservoir site area is regarded as a porous medium, and a fundamental °I)a + v k V(p + 7,r)
equation of the seepage field is: , where
represents a medium storage coefficient; Qs represents a volume source term; (.1) represents a porosity of a rock medium; t represents a time; p represents a groundwater velocity vector; the permeability coefficient of the rock medium is nonlinear, and the relationship -A 3 between the porosity and the permeability coefficient meets k=k, 00, where k, represents an initial permeability coefficient tensor of the medium and the initial hydrostatic P = pgh pressure distribution of the model s ° , and the oil pressure distribution when a main cavern is filled with oil during the operation period is P = As an optional implementation, in step (4), the sealing validity judgment basis adopts the vertical hydraulic gradient criterion, and as long as a vertical hydraulic gradient (10) is greater than 1, that is, the pore water pressure is greater than the self-weight stress of the rock, the sealing of a storage chamber can be ensured.
As an optional implementation, in step (4), construction procedures of the groundwater sealed oil storage reservoir are performed according to the national standard GB 50455-2008 As an optional implementation, in step (5), for monitoring the seepage pressure for a long time, a specific method is to install and bury a plurality of osmometers at different elevations in pressure measuring holes before the completion and operation, that is, to bury osmometers in layers and sections.
As an optional implementation, in step (6), a fundamental formula of the exponential smoothing method is: Sr(x) = aYtn-1(x) + (1 -a),511_1(x) , where St represents a smoothing value at a time t, and a represents a smoothing factor (0<a< 1) which reflects a proportion of data in different time channels in an exponential smoothing process; a determination formula [in(1-a)%)] (0 represents a percentage of the is: a = 1 -expl n I, where weight of the previous data; n represents a moving step size; Yt represents an observation value at the time t, and St_, represents a smoothing value at a time t-1. and different exponents n (1, 2, 3) respectively correspond to one-time exponentially-weighted smoothing, two-times exponentially-weighted smoothing and three-times exponentially-weighted smoothing.
As a further limitation, in step (7), the distribution rules of the seepage field in the underground oil storage reservoir can be found through the monitoring data and predicted data, and once there is abnormal monitoring or abnormal predicted data, the water curtain pressure or the number of water curtain holes in a working state is changed.
An analysis system for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir includes: a parameter acquisition module, configured to preliminarily design the water curtain system according to hydrogeol ogi cal and engineering geological investigation reports as well as the rock mechanical parameters obtained by tests and calculations by using an engineering analogy method and referring to the reference cases of the completed projects at home and abroad, and give an approximate parameter range, including a hole distribution mode of water curtain holes, a length of the water curtain holes, a distance between the water curtain holes, a number of the water curtain holes, a height difference between the water curtain holes and an oil storage cavern, and a water curtain pressure; a finite element analysis module, configured to perform finite element analysis, establish a plurality of multi-physical field coupling simulation models based on the obtained parameter data and geological data as well as the conditions of a pressure seepage field of a reservoir site area, and perform analog calculations of a plurality of proposed design parameters of the water curtain system; a judgment module, configured to judge the feasibility of the calculated water curtain parameters based on the validity judgment basis-vertical hydraulic gradient criterion, where if a certain parameter range is not feasible at all, it means that the selected parameter range has a larger deviation from the actual needs and the previous case cannot be referenced, and then, a range is selected again until a final construction scheme is determined; a monitoring module, configured to monitor the seepage pressure around the oil storage reservoir for a period of time, and collect time series monitoring values to detect the state of the oil reservoir during an operation period; a prediction module, configured to linearly predict the collected time series data, establish a reasonable estimation formula by an exponential smoothing method, predict the change trend of the seepage pressure in the future, compare a predicted result with an actual value measured later, and verify the predicted result; and an adjusting module, configured to adjust the parameters of the water curtain system in real time with reference to the hydrological monitoring data during a constniction period and the operation period and the predicted data during the operation period in the future.
Compared with the prior art, the present disclosure has the following beneficial effects: The present disclosure provides a method basis for three stages of design, construction and operation of the water curtain system of the groundwater sealed oil storage reservoir, and obtains the relevant parameter data required by a scheme in indoor tests with reference to geological investigation data and existing relevant research cases. A selection range of specific parameters of the water curtain system can be quickly and accurately reduced by a finite element analysis method, the determination of a final design and construction scheme is accurate and time-saving, the feasibility is high, and the oil leakage rate is low.
Through the real-time monitoring of the seepage pressure during the operation stage, the state of the oil reservoir can be known at all times so as to avoid untimely measures in emergencies One-time exponentially-weighted smoothing can be used for quickly predicting the change trend of the seepage pressure, which is enough to predict and respond to the conditions that may occur in a certain period of time in the future, thereby effectively reducing the water inflow and reducing the operation cost. The present disclosure has simple principle and strong practicability, provides a method guidance and a reference basis for the design and construction of water sealed oil reservoirs in the future, and solves the problems of lacking design standard and poor operation effect of water curtain systems of underground oil storage reservoirs
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings constituting a part of the present disclosure are used to provide further understanding of the present disclosure. Exemplary embodiments of the present disclosure and descriptions thereof are used to explain the present disclosure, and do not constitute an improper limitation to the present disclosure.
FIG. 1 is aflowchart of implementation steps.
DETAILED DESCRIPTION
The present disclosure is further described below with reference to the accompanying drawings and embodiments.
It should be pointed out that the following detailed descriptions are all illustrative and are intended to provide further descriptions of the present disclosure. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the present disclosure belongs.
It should be noted that the terms used herein are merely used for describing specific implementations, and are not intended to limit exemplary implementations of the present disclosure. As used herein, the singular form is also intended to include the plural form unless the context clearly dictates otherwise. In addition, it should further be understood that, terms "comprise" and/or "include" used in this specification indicate that there are features, steps, operations, devices, components, and/or combinations thereof According to on-site engineering geological and hydrogeological investigation reports and referring to the completed projects at home and abroad, an engineering analogy method is performed to preliminarily determine a parameter range of a water curtain system of a groundwater sealed oil storage reservoir. Multi-physical field coupling simulation models (COMSOL) are established by finite element analysis with reference to the data obtained by indoor tests, and the given parameter range of the water curtain system is accurately evaluated according to the judgment basis of the vertical hydraulic gradient criterion. If the parameter range does not meet the judgment basis, the parameters are unreasonable and are discarded. If the parameter range meets the judgment basis, the parameters meet the water sealability requirement. The water curtain parameters that meet the water sealability and cannot cause a larger water inflow are selected as a feasible scheme to be constructed. After completion, the seepage pressure is still monitored in real time, and osmometers are buried at different elevations around a cavern for periodic measurement, so as to obtain time series data for evaluating the operation effect and predicting the trend of the seepage pressure in the future (exponential smoothing method), and obtain information for comprehensively evaluating the efficiency of the water curtain system and providing feedback and correction opinions to guide the operation.
As shown in FIG. 1, an analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir includes: (1) Rock samples in a reservoir site area are collected, and an indoor triaxial compression test and a shear seepage coupling test on a structural plane are performed, so as to obtain rock mechanical parameters and structural plane related parameters. Relevant mechanical parameters (rock density, hardness, surface roughness, etc.) can be quickly obtained by traditional test methods, or relevant mechanical parameters (elastic modulus, Poisson's ratio, joint shear stiffness, hydraulic opening, etc.) can be obtained by calculations.
(2) The water curtain system is preliminarily designed according to hydrogeological and engineering geological investigation reports as well as the rock mechanical parameters obtained by indoor tests and calculations by using an engineering analogy method and referring to the reference cases (Pyongtaek in Korea, U-2 in Korea, Kuji in Japan, etc.) of the completed projects at home and abroad, and an approximate parameter range is given, including a hole distribution mode of water curtain holes (horizontal hole distribution, vertical hole distribution, or inclined hole distribution), a length of the water curtain holes, a distance between the water curtain holes, a number of the water curtain holes, a height difference between the water curtain holes and an oil storage cavern (a distance difference between the water curtain holes in vertical hole distribution and the cavern, and a position relationship between the water curtain holes in inclined hole distribution and the cavern), a water curtain pressure, etc. (3) Finite element analysis is performed, a plurality of multi-physical field coupling simulation models are established based on the obtained parameter data and geological data as well as the conditions of a pressure seepage field of the reservoir site area, and analog calculations are performed on a plurality of proposed design parameters of the water curtain system.
(4) The validity judgment basis-vertical hydraulic gradient criterion is proposed, and the water curtain parameters that can meet the judgment basis are considered to be theoretically feasible. Since the surrounding rock grade is good and the stability can be met, economic benefits are considered. In order to reduce the cost of water pumping and drainage, the water curtain parameters that cause a larger water inflow in the cavern are excluded, and feasible schemes are retained. If a certain parameter range is not feasible at all (sealing failure), it means that the selected parameter range has a larger deviation from the actual needs, the previous case cannot be referenced, and a range needs to be selected again in (2) until a final con structi on scheme is determined.
(5) After completion, the seepage pressure around the oil storage reservoir is still monitored for a long time, and time series monitoring values are collected to observe and evaluate the state of the oil reservoir during an operation period, thereby knowing the operation state of the water curtain system at any time.
(6) The collected time series data is linearly predicted, a reasonable estimation formula is established by an exponential smoothing method, the change trend of the seepage pressure in the future is predicted, a predicted result is compared with an actual value measured later, and the predicted result is verified. The key to exponential smoothing prediction is the selection of a smoothing factor a. However, the smoothing factor a is easily affected by subjective factors, so a large number of predictions are required to verify the desirable range of the selected a.
(7) The parameters of the water curtain system are adjusted in real time with reference to the hydrological monitoring data during a construction period and the operation period and the predicted data during the operation period in the future, so that the risks existing in the operation are reduced, the operation cost is saved, and the excessive water inflow in the cavern is avoided. The water curtain system is comprehensively evaluated, and correction opinions are proposed to guide the subsequent works.
As a further limitation, in step (1), the selected rock mechanical parameters include hardness, density, surface roughness, elastic modulus, Poisson's ratio, joint shear stiffness and hydraulic opening; the mechanical parameters are obtained by testing random-shaped rock blocks excavated by a blasting method, where the hardness is quickly measured by a Schmidt rebound apparatus; the density is quickly calculated according to the mass and volume of the rock blocks; the surface roughness is obtained by measuring cylindrical samples prepared from the rock samples by a roughness meter; the elastic modulus and the Poisson's ratio are obtained by a rock indoor triaxial test carried out by an RLW-500 type rock triaxial apparatus; and the joint shear stiffness and the hydraulic opening are calculated by a shear seepage coupling test on an indoor structural plane.
As a further limitation, in step (I), the triaxial compression test and the test of each of the rock mechanical parameters are performed according to the national standard GB/T 50266-2013.
As a further limitation, in step (2), the reference cases, such as Pyongtaek in Korea, U-2 in Korea and Kuji in Japan, of the completed projects at home and abroad in the engineering analogy method are all completed projects and can be found in literatures.
As a further limitation, in step (3), the finite element analysis needs to consider boundary conditions and initial conditions, and finally determine the distribution of water heads by solving differential equations. The analog calculation of a seepage field refers to = 1 k Darcy-Wei sb ach Formula: 7 8X,, where k represents a medium permeability coefficient, y represents a weight density of water, p represents a pore water pressure; v, represents a flow rate of groundwater seepage; z represents a vertical coordinate; and x, represents a distance along an x direction.
As a further limitation, in step (3), the sizes of the established multi-physical field coupling simulation models are all based on the construction design, and medium parameters and physical field applications are set according to the investigation reports. The surrounding rock in the reservoir site area is regarded as a porous medium, and a fundamental equation of s +v -at -V1P+7"ni=g,-0 where So represents a
the seepage field is:
medium storage coefficient; Qs represents a volume source term, (1) represents a porosity of a rock medium; t represents a time; and x represents a groundwater velocity vector, The permeability coefficient of the rock medium is nonlinear, and the relationship between the A.3 k =k" porosity and the permeability coefficient meets: ',0c: , where ko represents an initial permeability coefficient tensor of the medium. The initial hydrostatic pressure distribution of the model is P° = Pg and the oil pressure distribution when a main cavern is filled with oil during the operation period is = As a further limitation, in step (4), the sealing validity judgment basis adopts the vertical hydraulic gradient criterion proposed by ABERG in 1977, and it is considered that as long as a vertical hydraulic gradient (Jo) is greater than 1, that is, the pore water pressure is greater than the self-weight stress of the rock, the sealing of a storage chamber can be ensured.
As a further limitation, in step (4), construction procedures of the groundwater sealed oil storage reservoir are performed according to the national standard GB 50455-2008.
As a further limitation, in step (5), for monitoring the seepage pressure for a long time, a specific method is to install and bury 5 osmometers at different elevations in pressure measuring holes before the completion and operation, that is, to bury osmometers in layers and sections. The osmometer adopts vibrating wire type water pressure. The working principle is that the water pressure in the soil is transmitted to a thin-plate elastic element, and the deformation of the elastic element causes the change of the steel string tension, so that a water pressure value is measured according to the change of the steel string frequency. The relevant indicators of the osmometer are: ranee: 1.0 NIT'a; accuracy: +0.1% F.S.; sensitivity: 0.025% ES,; working temperature: -20-60°C; waterproof pressure resistance: 1.0 N4Pa; 25% over range should be able to work normally.
As a further limitation, in step (6), a fundamental formula of the exponential smoothing method is: SP(x) = aYri(x) + (1 -a)Sr_1(x), where St represents a smoothing value at a time t, and a represents a smoothing factor (0<a<1) which reflects a proportion of data in different time channels in an exponential smoothing process; a determination formula is: a = 11.(1-0...%)1 1 -expt i, where a represents a percentage of the weight of the previous data; n represents a moving step size; if, represents an observation value at the time t, and St_i represents a smoothing value at a time t-1; and different exponents n (1, 2, 3) respectively correspond to one-time exponentially-weighted smoothing, two-times exponentially-weighted smoothing and three-times exponentially-weighted smoothing. Since the one-time exponentially-weighted smoothing is suitable for a time series without obvious rules, this technical solution adopts the one-time exponentially-weighted smoothing to linearly predict the seepage pressure.
As a further limitation, in step (7), the efficiency of the water curtain system can be comprehensively evaluated through the data obtained through this technical solution, and the distribution rules of the seepage field in the underground oil storage reservoir can be found through the monitoring data and predicted data. Once there is abnormal monitoring or abnormal predicted data, corresponding remedial measures can be taken in time. In the event of the excessive water inflow in the cavern or the arrival of abnormal weather, risks can be reduced by changing the water curtain pressure or the number of water curtain holes in a working state, and the cost can be saved.
A person skilled in the art should understand that the embodiments of the present disclosure may be provided as a method, a system, or a computer program product. Therefore, the present disclosure may use a form of hardware-only embodiments, software-only embodiments, or embodiments combining software and hardware. In addition, the present disclosure may use a form of a computer program product that is implemented on one or more computer-usable storage media (Including but not limited to a disk memory, a CD-ROM, an optical memory, and the like) that include computer-usable program code.
The present disclosure is described with reference to flowcharts and/or block diagrams of the method, device (system), and computer program product in the embodiments of the present disclosure. It is to be understood that computer program instructions can implement each procedure and/or block in the flowcharts and/or block diagrams and a combination of procedures and/or blocks in the flowcharts and/or block diagrams. These computer program instmctions may be provided for a general-purpose computer, a dedicated computer, an embedded processor, or a processor of any other programmable data processing device to generate a machine, so that the instructions executed by a computer or a processor of any other programmable data processing device generate an apparatus for implementing a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.
These computer program instructions may also be stored in a computer readable memory that can instruct the computer or any other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory generate an artifact that includes an instruction apparatus. The instruction apparatus implements a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.
These computer program instructions may also be loaded onto a computer or another programmable data processing device, so that a series of operations and steps are performed on the computer or the another programmable device, thereby generating computer-implemented processing. Therefore, the instructions executed on the computer or the another programmable device provide steps for implementing a specific function in one or more processes in the flowcharts and/or in one or more blocks in the block diagrams.
The foregoing descriptions are exemplary embodiments of the present disclosure but are not intended to limit the present disclosure. The present disclosure may include various modifications and changes for a person skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure.
The specific implementations of the present disclosure are described above with reference to the accompanying drawings, but are not intended to limit the protection scope of the present disclosure. A person skilled in the art should understand that various modifications or deformations may be made without creative efforts based on the technical solutions of the present disclosure, and such modifications or deformations shall fall within the protection scope of the present disclosure.
Claims (10)
- CLAIMSWhat is claimed is: 1. An analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir, comprising: (1) collecting rock samples in a reservoir site area, and performing a triaxial compression test and a shear seepage coupling test on a structural plane, so as to obtain rock mechanical parameters and structural plane related parameters; (2) preliminarily designing the water curtain system according to hydrogeological and engineering geological investigation reports as well as the rock mechanical parameters obtained by tests and calculations by using an engineering analogy method and referring to the reference cases of the completed projects at home and abroad, and giving an approximate parameter range, comprising a hole distribution mode of water curtain holes, a length of the water curtain holes, a distance between the water curtain holes, a number of the water curtain holes, a height difference between the water curtain holes and an oil storage cavern, and a water curtain pressure; (3) performing finite element analysis, establishing a plurality of multi-physical field coupling simulation models based on the obtained parameter data and geological data as well as the conditions of a pressure seepage field of the reservoir site area, and performing analog calculations of a plurality of proposed design parameters of the water curtain system; (4) judging the feasibility of the calculated water curtain parameters based on the validity judgment basis-vertical hydraulic gradient criterion, wherein if a certain parameter range is not feasible at all, it means that the selected parameter range has a larger deviation from the actual needs and the previous case cannot be referenced; returning to step (2), and selecting a range again until a final construction scheme is determined; (5) after completion, continuing to monitor the seepage pressure around the oil storage reservoir for a period of time, and collecting time series monitoring values to detect the state of the oil reservoir during an operation period, (6) linearly predicting the collected time series data, establishing a reasonable estimation formula by an exponential smoothing method, predicting the change trend of the seepage pressure in the future, comparing a predicted result with an actual value measured later, and verifying the predicted result; and (7) adjusting the parameters of the water curtain system in real time with reference to the hydrological monitoring data during a construction period and the operation period and the predicted data during the operation period in the future, wherein in step (6), a fundamental formula of the exponential smoothing method is: Sr (x) = ayriz (x) + (1 -a).572_1(x), wherein St represents a smoothing value at a time t, and a represents a smoothing factor (0<a<1) which reflects a proportion of data in different time channels in an exponential smoothing process; a determination formula is: a = 1 -iin(1-o%)] expl n I, wherein zo represents a percentage of the weight of the previous data; n represents a moving step size; Yt represents an observation value at the time t, and St_1 represents a smoothing value at a time t-1; and different exponents n (1, 2, 3) respectively correspond to one-time exponentially-weighted smoothing, two-times exponentially-weighted smoothing and three-times exponentially-weighted smoothing.
- 2. The analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir according to claim 1, wherein in step (1), the selected rock mechanical parameters comprise hardness, density, surface roughness, elastic modulus, Poisson's ratio, joint shear stiffness and hydraulic opening; the mechanical parameters are obtained by testing random-shaped rock blocks excavated by a blasting method, wherein the hardness is quickly measured by a Schmidt rebound apparatus; the density is quickly calculated according to the mass and volume of the rock blocks; the surface roughness is obtained by measuring cylindrical samples prepared from the rock samples by a roughness meter; the elastic modulus and the Poisson's ratio are obtained by a rock indoor triaxial test carried out by an RLW-500 type rock triaxial apparatus; and the joint shear stiffness and the hydraulic opening are calculated by a shear seepage coupling test on an indoor structural plane.
- 3. The analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir according to claim 1, wherein in step (1), the triaxial compression test and the test of each of the rock mechanical parameters are performed according to the national standard GB/T 50266-2013.
- 4. The analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir according to claim 1, wherein in step (4), construction procedures of the groundwater sealed oil storage reservoir are performed according to the national standard GB 50455-2008.
- 5. The analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir according to claim 1, wherein in step (3), the finite element analysis needs to consider boundary conditions and initial conditions, and finally determine the distribution of water heads by solving differential equations; the analog v, - I calculation of a seepage field refers to Darcy-Weisbach Formula: 7,,DXI wherein k represents a medium permeability coefficient; 7 represents a weight density of water; P represents a pore water pressure; represents a flow rate of groundwater seepage; z represents a vertical coordinate; and x1 represents a distance along an x direction.
- 6. The analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir according to claim 1, wherein in step (3), the sizes of the established multi-physical field coupling simulation models are all based on the construction design, and medium parameters and physical field applications are set according to the investigation reports; the surrounding rock in the reservoir site area is regarded as a porous medium, and a fundamental equation of the seepage field is: s e31) + v. a at -V(p +7".7) = -0 ot (v.u) wherein represents a medium storage coefficient; Q3 represents a volume source term; 0 represents a porosity of a rock medium; t represents a time, P represents a groundwater velocity vector; z represents a vertical coordinate; P represents a pore water pressure; the permeability coefficient of the rock medium is nonlinear, and the relationship th k =k" between the porosity and the permeability coefficient meets: ', 00, wherein k° represents an initial permeability coefficient tensor of the medium and the initial hydrostatic pressure distribution of the model is P° =Pigh, and the oil pressure distribution when a main cavern is filled with oil during the operation period is P P.
- 7. The analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir according to claim 1, wherein in step (4), the sealing validity judgment basis adopts the vertical hydraulic gradient criterion, and as long as a vertical hydraulic gradient (Jo) is greater than 1, that is, the pore water pressure is greater than the self-weight stress of the rock, the sealing of a storage chamber can be ensured.
- 8. The analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir according to claim 1, wherein in step (5), for monitoring the seepage pressure for a long time, a specific method is to install and bury a plurality of osmometers at different elevations in pressure measuring holes before the completion and operation, that is, to bury osmometers in layers and sections.
- 9. The analysis method for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir according to claim 1, wherein in step (7), the distribution rules of the seepage field in the underground oil storage reservoir can be found through the monitoring data and predicted data, and once there is abnormal monitoring or abnormal predicted data, the water curtain pressure or the number of water curtain holes in a working state is changed.
- 10. An analysis system for designing and correcting a water curtain system of a groundwater sealed oil storage reservoir, comprising: a parameter acquisition module, configured to preliminarily design the water curtain system according to hydrogeological and engineering geological investigation reports as well as the rock mechanical parameters obtained by tests and calculations by using an engineering analogy method and referring to the reference cases of the completed projects at home and abroad, and give an approximate parameter range, comprising a hole distribution mode of water curtain holes, a length of the water curtain holes, a distance between the water curtain holes, a number of the water curtain holes, a height difference between the water curtain holes and an oil storage cavern, and a water curtain pressure; a finite element analysis module, configured to perform finite element analysis, establish a plurality of multi-physical field coupling simulation models based on the obtained parameter data and geological data as well as the conditions of a pressure seepage field of a reservoir site area, and perform analog calculations of a plurality of proposed design parameters of the water curtain system; a judgment module, configured to judge the feasibility of the calculated water curtain parameters based on the validity judgment basis-vertical hydraulic gradient criterion, wherein if a certain parameter range is not feasible at all, it means that the selected parameter range has a larger deviation from the actual needs and the previous case cannot be referenced, and then, a range is selected again until a final construction scheme is determined; a monitoring module, configured to monitor the seepage pressure around the oil storage reservoir for a period of time, and collect time series monitoring values to detect the state of the oil reservoir during an operation period; a prediction module, configured to linearly predict the collected time series data, establish a reasonable estimation formula by an exponential smoothing method, predict the change trend of the seepage pressure in the future, compare a predicted result with an actual value measured later, and verify the predicted result; and an adjusting module, configured to adjust the parameters of the water curtain system in real time with reference to the hydrological monitoring data during a construction period and the operation period and the predicted data during the operation period in the tliture.
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| PCT/CN2020/139206 WO2021136077A1 (en) | 2020-01-03 | 2020-12-25 | Analysis system and method for designing and correcting water curtain system of underground water-sealed oil storage |
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| CN112464552B (en) * | 2020-10-28 | 2022-10-25 | 山东大学 | Method and system suitable for predicting seepage field time sequence of underground water-sealed oil storage |
| CN113849880B (en) * | 2021-08-16 | 2024-06-25 | 长沙理工大学 | Roadbed non-uniform humidity field determination method considering wet-force coupling effect |
| CN114184531B (en) * | 2021-11-18 | 2023-05-12 | 中煤科工集团西安研究院有限公司 | Test device and test method for optimizing position and evaluating effect of water interception curtain |
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