Pore pressure prediction method and device based on three-dimensional fine crustal stress field

Abstract

The invention relates to the technical field of well logging, in particular to a pore pressure prediction method and device based on a three-dimensional fine crustal stress field, and the method comprises the steps: interpreting and constructing a geological structure model of a block where a target well is located through three-dimensional seismic wave data; a three-dimensional fine crustal stress field numerical solution is obtained based on finite element analysis in combination with the geological structure model of the block where the target well is located; and predicting a pore pressure curve and a safe drilling mud density window of the target well based on the seismic wave data and the three-dimensional fine crustal stress field numerical solution. According to the method, the pore pressure and the safe drilling mud density window of the target well are predicted by integrating three-dimensional fine ground stress and single-well geomechanics, and the pore pressure and the safe drilling mud density window of the target well do not need to be predicted by using logging data of a drilled well adjacent to the target well; compared with an existing mode of completing target well pore pressure and safe drilling mud density window prediction only based on well logging data of a drilled well adjacent to the target well, the method can be effectively applied to a target reservoir scene of a new block deep stratum.

Description

Technical Field

[0001] The invention relates to the technical field of well logging, and is a method and a device for predicting pore pressure based on a three-dimensional fine geostress field. Background Art

[0002] At present, the development target layers of the gas reservoirs in the oil and gas fields developed earlier are mainly located at a vertical depth of 7,000 to 8,000 meters. The drilling projects in this layer have no drilling and logging information from adjacent wells for reference. Compared with wells with drilled data for reference, the prediction of pore pressure and mud window is difficult.

[0003] Well logging data such as sonic logging and resistivity logging are currently the conventional methods for predicting and calculating formation pore pressure. Such calculations require reference data from nearby wells near the target well. For target reservoirs located in deep formations of new blocks, conventional methods cannot accurately predict pore pressure or accurately calculate the safe mud density window because there is no well logging data to refer to.

[0004] The accuracy and calculation precision of overburden pressure are important factors affecting the accuracy of pore pressure prediction. In the Eaton acoustic wave method for pore pressure prediction, the overburden pressure and the power function of the acoustic wave duration jointly determine the magnitude of the pore pressure gradient. An accurate analytical solution of the overburden pressure is an important guarantee for the accuracy of the pore pressure prediction results. The commonly used method for calculating overburden pressure when predicting the pore pressure gradient is the density integration method, that is, according to the distribution of the rock density of the formation and the vertical depth, from the ground to the target layer, the overburden pressure is calculated by integrating the density with the depth. The advantage of this method is that it is fast and efficient, and the disadvantage is that in strata with local structures such as anticlines, the arched structure of the anticline has a significant impact on the local stress distribution. The vertical stress values ​​at the top and bottom of the anticline vary with the depth position, and their values ​​are sometimes significantly different from the overburden pressure values ​​obtained by density integration. This makes it necessary to use a three-dimensional geostress numerical solution to predict pore pressure.

[0005] The necessity of using three-dimensional geostress numerical solution to predict mud density window lies in: first, the exploratory wells in the newly developed blocks have no logging data for the undrilled strata, so it is impossible to perform geomechanical analysis based on single well logging data and further mud window calculation. Only the numerical calculation results of three-dimensional geostress field can be used for relevant analysis and calculation; second, when the "normal fault stress state" appears, the upper limit of the mud density window is determined by the minimum horizontal principal stress value, and when the "reverse fault stress state" appears, the upper limit of the mud density window is determined by the pressure value of the overlying rock formation. In the oil and gas field blocks on the southern edge of the Junggar Basin, due to the large stratum fluctuations, at different depths of the same well location, the "normal fault stress state" and the "reverse fault stress state" may exist simultaneously, that is, the upper part is the normal fault stress state, the middle part is the reverse fault stress state, and the lower part returns to the normal fault stress state. This makes the mud density window analysis results obtained by the single well analysis method inaccurate. Summary of the invention

[0006] The present invention provides a pore pressure prediction method and device based on a three-dimensional fine geostress field, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problem that the pore pressure of a target well cannot be predicted based on single well logging data when there is no logging data in the undrilled formation part.

[0007] One of the technical solutions of the present invention is achieved by the following measures: a pore pressure prediction method based on a three-dimensional fine geostress field, comprising: The geological structure model of the block where the target well is located is constructed by interpreting the 3D seismic wave data; Combined with the geological structure model of the target well block, a three-dimensional fine-grained numerical solution of the geostress field is obtained based on finite element analysis; Based on seismic wave data and three-dimensional fine-grained numerical solution of geostress field, the pore pressure curve and safe drilling mud density window of the target well are predicted.

[0008] The following are further optimizations and / or improvements to the above technical solutions: The above-mentioned geological structure model of the block where the target well is located is combined with the finite element analysis to obtain the three-dimensional fine stress field numerical solution, including: Construct a corresponding finite element model based on the geological structure model of the block where the target well is located; Various loads and boundary conditions are applied to the finite element model to obtain the three-dimensional precise numerical solution of the geostress field.

[0009] The above-mentioned prediction of the pore pressure curve and safe drilling mud density window of the target well based on seismic wave data and three-dimensional fine stress field numerical solution includes: Extracting sound wave duration data based on seismic wave data; Extract overburden pressure based on three-dimensional precise geostress field numerical solution; Combining the acoustic wave duration data and the overburden formation pressure, the pore pressure at each point on the target well trajectory is obtained to form the pore pressure curve of the target well; The numerical solution of the three-dimensional fine stress field is analyzed, and the minimum horizontal principal stress component is selected as the upper limit of the mud density window; The maximum horizontal principal stress component and the minimum horizontal principal stress component are selected, and the collapse pressure is obtained based on the Moore-Coulomb law in combination with the pore pressure curve, the internal friction angle curve, and the bonding strength of the rock, as the lower limit of the mud density window.

[0010] The above also includes determining mud density, which is the sum of the lower limit of the mud window and the set parameters.

[0011] The second technical solution of the present invention is achieved by the following measures: a pore pressure prediction device based on a three-dimensional fine geostress field, comprising: Initial structural unit, the geological structural model of the block where the target well is located is constructed by interpreting the 3D seismic wave data; The first analysis unit combines the geological structure model of the block where the target well is located and obtains the three-dimensional fine stress field numerical solution based on finite element analysis; The second analysis unit predicts the pore pressure curve and safe drilling mud density window of the target well based on seismic wave data and three-dimensional fine stress field numerical solution.

[0012] The following are further optimizations and / or improvements to the above technical solutions: The first analysis unit comprises: Model conversion module, which constructs the corresponding finite element model according to the geological structure model of the block where the target well is located; The analysis and solution module determines the rock mechanical property parameter values ​​and horizontal tectonic stress coefficients, applies various loads and boundary conditions to the finite element model, and obtains a three-dimensional precise numerical solution of the geostress field.

[0013] The second analysis unit comprises: The pore pressure prediction module extracts the acoustic wave duration data based on the seismic wave data; extracts the overburden formation pressure based on the three-dimensional fine geostress field numerical solution; combines the acoustic wave duration data and the overburden formation pressure to obtain the pore pressure of each point on the target well trajectory and form the pore pressure curve of the target well; The mud window selection module analyzes the numerical solution of the three-dimensional fine stress field and selects the minimum horizontal principal stress component as the upper limit of the mud density window; the maximum horizontal principal stress component and the minimum horizontal principal stress component are selected, and the collapse pressure is obtained based on the Moore-Coulomb law in combination with the pore pressure curve, the internal friction angle curve, and the bonding strength of the rock as the lower limit of the mud density window.

[0014] The present invention integrates three-dimensional fine geostress and single-well geomechanics to predict the pore pressure and safe drilling mud density window of the target well. It is not necessary to use the logging data of the target well adjacent to the drilled well to predict the pore pressure and safe drilling mud density window of the target well. Compared with the existing method that can only complete the prediction of the pore pressure and safe drilling mud density window of the target well based on the logging data of the target well adjacent to the drilled well, the method disclosed in this embodiment can be effectively applied to the target reservoir scene of the deep formation of the new block. Further, the present invention uses a three-dimensional fine geostress field numerical solution to calculate the mud density window. Compared with the method of obtaining the mud density window based on single-well logging data, the calculation of the mud density window is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attached Figure 1 The figure is a flow chart of a prediction method of the present invention.

[0016] Attached Figure 2 This is another flow chart of the prediction method of the present invention.

[0017] Attached Figure 3 This is a plan view of the relative positions of the target well and existing wells in the Tugulu anticline block in Example 3 of the present invention.

[0018] Attached Figure 4 This is the profile and structural diagram of the main survey line TG201103 of the Tugulu anticline in Example 3 of the present invention.

[0019] Attached Figure 5 This is a schematic diagram of the geological structure model of the Tugulu anticline block in Example 3 of the present invention.

[0020] Attached Figure 6-a This is a model network diagram of the Abaqus finite element model of the Tugulu anticline block in Example 3 of the present invention.

[0021] Attached Figure 6-b This is a model network diagram of the Abaqus finite element model of the Tugulu anticline block in Example 3 of the present invention.

[0022] Attached Figure 7 It is a three-dimensional view and a plane projection view of the maximum horizontal principal stress distribution diagram of the J3q formation in the lower target layer of the LeTan 1 well in Example 3 of the present invention.

[0023] Attached Figure 8 This is a graph showing the variation of the values ​​of the three principal stress components of the three-dimensional fine geostress field numerical solution at the Le Tan 1 well with depth in Example 3 of the present invention.

[0024] Attached Fig. 9 This is a schematic diagram of the pore pressure and mud window prediction results of the LeTan 1 well in Example 3 of the present invention.

[0025] Attached Fig.10 The figure is a schematic diagram of the structure of a device of the present invention.

[0026] Attached Fig.11 This is a schematic diagram of another device structure of the present invention. DETAILED DESCRIPTION

[0027] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0028] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As attached Figure 1 As shown, the embodiment of the present invention discloses a pore pressure prediction method based on a three-dimensional fine geostress field, comprising: Step S110, constructing a geological structure model of the block where the target well is located by interpreting the three-dimensional seismic wave data; Step S120, combining the geological structure model of the block where the target well is located, and obtaining a three-dimensional fine geostress field numerical solution based on finite element analysis; Step S130, predicting the pore pressure curve and safe drilling mud density window of the target well based on the seismic wave data and the three-dimensional fine geostress field numerical solution.

[0029] The embodiment of the present invention discloses a pore pressure prediction method based on a three-dimensional fine geostress field, which integrates three-dimensional fine geostress and single-well geomechanics to predict the pore pressure and safe drilling mud density window of a target well. There is no need to use the logging data of the wells drilled adjacent to the target well to predict the pore pressure and safe drilling mud density window of the target well. Compared with the existing method of only being able to complete the prediction of the pore pressure and safe drilling mud density window of the target well based on the logging data of the wells drilled adjacent to the target well, the method disclosed in this embodiment can be effectively applied to the target reservoir scenario of the deep formation of the new block.

[0030] Embodiment 2: As attached Figure 2 As shown, the embodiment of the present invention discloses a pore pressure prediction method based on a three-dimensional fine geostress field, comprising: Step S210, constructing a geological structure model of the block where the target well is located by interpreting the three-dimensional seismic wave data.

[0031] In the above step S210, the seismic wave data of the block where the target well is located can be obtained in advance to understand the corresponding seismic profile and the distribution of major faults, geological stratification and lithology description, and then three-dimensional seismic wave data interpretation is performed. Finally, a geological structure model of the block where the target well is located is constructed based on the three-dimensional seismic wave data interpretation.

[0032] Step S220: construct a corresponding finite element model according to the geological structure model of the block where the target well is located.

[0033] In the above step S210, a corresponding finite element model, namely, an Abaqus finite element model, is constructed according to the geological structure model of the block where the target well is located by using existing software.

[0034] Step S230, applying various loads and boundary conditions to the finite element model to obtain a three-dimensional precise numerical solution of the geostress field.

[0035] The above step S230 implements finite element analysis. The basic steps of finite element analysis for solving problems include: 1. Apply load and solve (1) Define constraints (i.e., boundary conditions). The defined constraints include the upper limit of material deformation and fracture, etc. In this example, boundary conditions can be set from the four bottom edges and the upper and lower sides.

[0036] (2) Applied load, i.e., applied external stress conditions. Applied loads include vertical stress, horizontal stress, gravity load, etc. The initial load is gravity load, and the initial geostress field and gravity load form a balanced initial geostress field. The application of the initial geostress field is achieved by directly assigning values ​​to the stress points of each unit through Abaqus software and then performing elastic mechanical equilibrium iteration.

[0037] Here, when applying the load, the rock mechanical property parameter values ​​can be determined according to the rock sample test data and other existing data for the initial ground stress field, and the horizontal tectonic stress coefficient can be determined according to the characteristics of the tectonic movement. When the stratum fluctuations are large, the minimum horizontal principal stress coefficient corresponding to the reverse fault is generally greater than 1, that is, the overburden pressure is less than the minimum horizontal principal stress, while the stress overburden pressure corresponding to the normal fault is greater than the maximum horizontal principal stress.

[0038] (3) Solution: When the boundary conditions are determined, the solution is obtained through finite element analysis. If the boundary conditions cause material rupture, the calculation is interrupted and the boundary conditions are adjusted to continue the calculation.

[0039] (II) Post-processing (1) Plot the results, such as the vector diagram of the stress field distribution direction, the contour diagram of the maximum principal stress, the vector diagram of the maximum principal strain, etc. (2) Analyze the results. Analyze the rationality of the boundary conditions by analyzing the graph of the drawn results.

[0040] Step S240, extracting sound wave duration data based on the seismic wave data.

[0041] Step S250, extracting the overburden pressure based on the three-dimensional fine geostress field numerical solution.

[0042] Step S260, combining the acoustic wave duration data and the overburden formation pressure, obtains the pore pressure of each point on the target well trajectory, and forms a pore pressure curve of the target well.

[0043] Step S270, analyzing the three-dimensional fine geostress field numerical solution, and selecting the minimum horizontal principal stress component as the upper limit of the mud density window.

[0044] Step S280, select the maximum horizontal principal stress component and the minimum horizontal principal stress component, and combine the pore pressure curve, the internal friction angle curve, and the bonding strength of the rock to obtain the collapse pressure based on the Moore-Coulomb law as the lower limit of the mud density window.

[0045] Step S290, determine the mud density, which is the sum of the lower limit of the mud window and the set parameter. The set parameter in this step can be 0.2.

[0046] The above steps S260 to S290 can all be completed in Drillworks.

[0047] In the above embodiment, a three-dimensional fine geostress field numerical solution is used to calculate the pore pressure and mud density window of the target well. Compared with the method of obtaining the pore pressure and mud density window of the target well based on single well logging data, the calculated mud density window is more accurate and more suitable for target wells with large formation fluctuations in the block.

[0048] Example 3: Taking the Tugulu anticline block as an example, the method disclosed in the above embodiment is applied to predict the pore pressure curve and safe drilling mud density window of the target well, specifically including: 1. Overview of the Tugulu anticline block The Tugulu anticline block includes several wells such as Tu-1 that have been drilled with the upper reservoir as the target layer. Figure 3 The figure shows the plan view of the Tugulu anticline block, which shows the relative position of the target well Le Tan 1. The length and width of the block model are 20.5 km and 15.5 km respectively, the maximum depth is 12 km, and the plane grid size is 500*500 meters. Figure 3 It can be seen that among the strata passed by the trajectory of Le Tan 1 Well, the upper strata are strata that have experienced a significant uplift. This part of the strata has experienced a movement of first compaction and then uplift. The calculation of the normal compaction curve of the strata requires special attention; the lower strata are in-situ normal compaction, and have a different slope from the normal compaction trend curve of the upper strata. The specific situation needs to be analyzed in combination with the pore pressure data of the upper wells.

[0049] like Figure 4Shown is the seismic profile and main fault distribution map of Well Letan 1. The vertical coordinate value is the data information in the time domain. The fault forms in the block are mainly reverse faults and thrust faults, which means that the horizontal stress component in the block will have a higher value.

[0050] The target well analyzed in this study is Le Tan 1 Well, and its target layer is mainly the lower "source oil and gas layer - reservoir oil and gas layer - cap rock" combination below 6000 meters, including the Kalaza Formation, Sangonghe Formation, and the Jurassic Badaowan Formation below. The target layers of the upper wells such as Tu 1 Well that have been drilled are the Kalaza Formation and Ziniquanzi Formation, as shown in Table 1. Table 1 shows the geological stratification and lithology description table of Le Tan 1 Well obtained based on the analysis of seismic information. The results obtained based on the analysis of seismic wave information indicate that the upper reservoir is the Paleogene Ziniquanzi Formation, the middle reservoir is the Cretaceous Qingshuihe Formation, and the lower reservoir is the Jurassic Kalaza Formation. These three reservoirs have oil and gas shows to varying degrees. It is predicted that the Ziniquanzi Formation show section is 1497m~2052m, the Qingshuihe Formation show section is 6500m~6660m, and the Jurassic Kalaza Formation show section is 6660m~6920m.

[0051] 2. Description of the 3D geostress field in the Tugulu anticline The plane position and stratigraphic information of the Tugulu anticline block and several wells in the block have been Figure 3 and Figure 4 and are given in Table 1. Therefore, the geological structure model of the block where the target well is located is as follows Figure 5 As shown. Figure 5 It can be seen that there are many faults in the block, and they are reverse faults or thrust faults, indicating that the maximum horizontal ground stress in the block is high. The block is cut by several thrust faults, and the anticline structure formed is obvious. During the orogenic movement, the fault site is the location of displacement discontinuity, and the tangential displacement on both sides of the fault is discontinuous and the normal displacement is continuous. After hundreds of millions of years of geological period, the current stress state is mainly determined by local structures such as gravity and anticlines. The influence of tectonic stress is still there, but after hundreds of millions of years of geological period, the magnitude of tectonic stress has been significantly weakened.

[0052] Figure 6-a and Figure 6-b The given finite element model fully inherits Figure 5 The Abaqus finite element model includes 370,000 nodes and about 90,000 C3D20R-20 high-precision elements. Figure 6-aThe boundaries of the finite element Abaqus model are: the bottom surface and the four normal zero displacement boundaries; the top surface is the ground, a free boundary. The initial load is the gravity load. The initial geostress field and the gravity load form a balanced initial geostress field. The application of the initial geostress field is achieved by directly assigning values ​​to the stress points of each unit through Abaqus software and then performing elastic mechanical equilibrium iterations.

[0053] When simulating faults, this model is simplified: only the changes in material properties on both sides of the fault are considered, and the simulation of the fault plane itself is not considered, that is, the fault plane is not regarded as a fracture plane. Since there is only gravity load in the model, and the model is used to calculate the static current geostress field. There is no relative movement on both sides of the fault during this calculation process, so this simplification is reasonable. The initial value of the geostress field of the block model comes from the single-well geostress field analysis results of Tugu 1 well. When inputting, the lateral pressure coefficient (that is, the ratio of the two horizontal principal stress components to the overburden pressure) is directly converted from the single-well geostress field analysis results.

[0054] Figure 7 The maximum horizontal principal stress component distribution diagram of the J3q formation of the target layer of Le Tan 1 well obtained by three-dimensional fine geostress field analysis is given. Figure 7 Including three-dimensional distribution diagram and two-dimensional plane distribution diagram. This maximum horizontal principal stress is the maximum horizontal principal stress at the location of Le Tan 1 well. It is not horizontal at other locations except the top of the anticline. In the three-dimensional stress principal stress space, it is actually the middle principal stress component Smid.

[0055] Due to the influence of formation fluctuation, the maximum horizontal principal stress distribution of the target layer of Le Tan 1 Well changes significantly with the horizontal position. The direction of the maximum horizontal principal stress component at the Le Tan 1 Well position at the top of the anticline is basically distributed in the north-south direction. At this position, the vertical stress component is the minimum principal stress component, and the stress format is the reverse fault stress format.

[0056] Figure 8 The curves showing the variation of the three principal stress components with depth at the Letan 1 well location are given for the numerical solution of the three-dimensional fine geostress field in the block.

[0057] (III) Using the method of the present invention to predict the pore pressure and mud window of Le Tan 1 well Based on the above three-dimensional fine geostress field numerical solution, the stress component value of the geostress field at the target well trajectory point can be extracted and input into the Drillworks single well pore pressure prediction and safe drilling mud density window analysis tool. Then extract the layer velocity data from the seismic wave data. Based on the layer velocity, pore pressure prediction and mud density window calculation based on three-dimensional geostress field and layer velocity can be performed. Table 2 is a table of mud density window values ​​for each formation in Le Tan 1 well. Fig. 9 The pore pressure and mud density window prediction results of Letan 1 well based on the above principle are given. The approximate locations of Shengjinkou Formation, Kalaza Formation, Qigu Formation and other formations are marked in the figure. The details between the upper and lower source-reservoir-caprock combinations are not marked.

[0058] Fig. 9 The left column is the gamma logging data obtained from the latest drilling. The second column on the left is the acoustic duration converted from the longitudinal wave layer velocity. This curve has been corrected by the latest drilling logging data on the upper part. The purple line in the third column on the left is the formation rock density calculated by the Gardener empirical formula method using the acoustic duration in the second column on the left. The rock density has been verified by the rock density parameters obtained from the logging data, which shows that the layer velocity curve in the second column on the left is credible. Due to the geological history of the formation being compacted first and then uplifted, the normal compaction trend line in the second column on the left is not a straight line, but is composed of multiple line segments. The existing actual drilling mud has reached a depth of nearly 5,800 meters. At a vertical depth of nearly 4,000 meters, the wellbore diameter is severely expanded, resulting in poor quality of logging data there. A gas invasion event occurred near 2,300 meters.

[0059] Fig. 9 The right column includes many curves, which are more complicated to analyze. First, this column includes the curves after the numerical solution of the three-dimensional geostress field in the Tugulu anticline block at the Letan 1 well is converted into a stress gradient form, including the normal stress / overburden pressure along the Z-axis-3D_overburden pressure and 3D_minimum horizontal principal stress. The theoretical value of pore pressure calculated based on the acoustic wave duration curve and the overburden pressure 3D_overburden pressure is the light green curve, and the empirical value of pore pressure is the predicted value of pore pressure given on the basis of the theoretical pore pressure curve combined with previous experience and the existing actual drilling information above.

[0060] The collapse pressure SFG obtained based on the acoustic wave curve and the three-dimensional principal stress numerical solution curve is: Fig. 9 The red curve in the right column. In some formations, because the values ​​of the strength parameters such as the friction angle and cohesive strength calculated from the acoustic wave are relatively high, the calculated collapse pressure is less than the pore pressure. The lower limit of the mud density window at such a depth section will be the value of the pore pressure. The upper limit of the mud density window is the smaller of the 3D_minimum horizontal principal stress curve and the 3D_overburden pressure. This shows that the three-dimensional geostress numerical solution can automatically and accurately select the minimum principal stress component as the upper limit of the mud window under different stress states. This is difficult to achieve in single-well geomechanical analysis. This is one of the advantages of using the three-dimensional geostress field numerical solution to calculate the mud density window.

[0061] Fig. 9The trend of the pore pressure curve in the right column is: the top Shawan Formation is normal pressure, and the pressure coefficient increases rapidly to a high pressure of more than 1.8 after entering the Anjihaihe Formation, and then gradually drops to about 1.5 in the Ziniquanzi Formation and Donggou Formation, and then gradually increases to a high pressure of about 2.5 in the Lianmuqin and Shengjinkou Formations. The pressure coefficient decreases in the Hutubihe Formation, increases in the Qingshuihe Formation, and decreases again in the Kalaza Formation, and its value remains between 2.2-2.4. Since the overburden pressure curve in the figure is significantly lower than the value of the actual drilling mud curve, it shows that the overburden pressure of the rock in the depth section below 4400 meters of the well is greatly affected by the local structure. This phenomenon illustrates the necessity and importance of three-dimensional geostress field analysis.

[0062] Figure 8 The black square symbols in the right column represent the actual drilling mud density values ​​to date. In the fault fracture zone at a depth of about 3,200 meters, mud leakage was encountered and pressure plugging was carried out. The entire drilling operation was relatively smooth without encountering serious accidents, indicating that the mud density window selection in this article is correct and the accuracy meets the engineering needs.

[0063] Embodiment 4: As attached Fig.10 As shown, the embodiment of the present invention discloses a pore pressure prediction device based on a three-dimensional fine geostress field, comprising: Initial structural unit, the geological structural model of the block where the target well is located is constructed by interpreting the 3D seismic wave data; The first analysis unit combines the geological structure model of the block where the target well is located and obtains the three-dimensional fine stress field numerical solution based on finite element analysis; The second analysis unit predicts the pore pressure curve and safe drilling mud density window of the target well based on seismic wave data and three-dimensional fine stress field numerical solution.

[0064] Embodiment 5: As attached Fig.11 As shown, the embodiment of the present invention discloses a pore pressure prediction device based on a three-dimensional fine geostress field, comprising: Initial structural unit, the geological structural model of the block where the target well is located is constructed by interpreting the 3D seismic wave data; Model conversion module, which constructs the corresponding finite element model according to the geological structure model of the block where the target well is located; The analysis and solution module determines the rock mechanical property parameter values ​​and horizontal tectonic stress coefficients, applies various loads and boundary conditions to the finite element model, and obtains a three-dimensional precise numerical solution of the geostress field; The pore pressure prediction module extracts the acoustic wave duration data based on the seismic wave data; extracts the overburden formation pressure based on the three-dimensional fine geostress field numerical solution; combines the acoustic wave duration data and the overburden formation pressure to obtain the pore pressure of each point on the target well trajectory and form the pore pressure curve of the target well; The mud window selection module analyzes the numerical solution of the three-dimensional fine stress field and selects the minimum horizontal principal stress component as the upper limit of the mud density window; the maximum horizontal principal stress component and the minimum horizontal principal stress component are selected, and the collapse pressure is obtained based on the Moore-Coulomb law in combination with the pore pressure curve, the internal friction angle curve, and the bonding strength of the rock as the lower limit of the mud density window.

[0065] Embodiment 6: The embodiment of the present invention discloses a storage medium, on which is stored a computer program that can be read by a computer, and the computer program is configured to execute a pore pressure prediction method based on a three-dimensional fine stress field when running.

[0066] The above storage medium may include, but is not limited to: a USB flash drive, a read-only memory, a mobile hard disk, a magnetic disk or an optical disk, and other media that can store computer programs.

[0067] Embodiment 7: The embodiment of the present invention discloses an electronic device, including a processor and a memory, wherein the memory stores a computer program, and the computer program is loaded and executed by the processor to implement a pore pressure prediction method based on a three-dimensional fine stress field.

[0068] The processor may be a central processing unit (CPU), a general purpose processor, a digital signal processor (DSP), an ASIC, an FPGA or other programmable logic device, a transistor logic device, a hardware component or any combination thereof. It may implement or execute various exemplary logic blocks, modules and circuits described in conjunction with the disclosure of this application. It may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and the like. The memory may include, but is not limited to, various media that can store computer programs, such as a USB flash drive, a read-only memory, a mobile hard disk, a magnetic disk or an optical disk.

[0069] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present application may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0070] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0071] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0072] The above technical features constitute the best embodiment of the present invention, which has strong adaptability and best implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A pore pressure prediction method based on three-dimensional fine geostress field, characterized in that: include: The geological structure model of the block where the target well is located is constructed by interpreting the 3D seismic wave data; Combined with the geological structure model of the target well block, a three-dimensional fine-grained numerical solution of the geostress field is obtained based on finite element analysis; Based on seismic wave data and three-dimensional fine-grained numerical solution of geostress field, the pore pressure curve and safe drilling mud density window of the target well are predicted.

2. The pore pressure prediction method based on three-dimensional fine geostress field according to claim 1 is characterized in that: The method combines the geological structure model of the block where the target well is located and obtains a three-dimensional fine geostress field numerical solution based on finite element analysis, including: Construct a corresponding finite element model based on the geological structure model of the block where the target well is located; Various loads and boundary conditions are applied to the finite element model to obtain the three-dimensional precise numerical solution of the geostress field.

3. The pore pressure prediction method based on three-dimensional fine geostress field according to claim 1 or 2, characterized in that: The method of predicting the pore pressure curve and safe drilling mud density window of the target well based on seismic wave data and three-dimensional fine geostress field numerical solution includes: Extracting sound wave duration data based on seismic wave data; Extract overburden pressure based on three-dimensional precise geostress field numerical solution; Combining the acoustic wave duration data and the overburden formation pressure, the pore pressure at each point on the target well trajectory is obtained to form the pore pressure curve of the target well; The numerical solution of the three-dimensional fine stress field is analyzed, and the minimum horizontal principal stress component is selected as the upper limit of the mud density window; The maximum horizontal principal stress component and the minimum horizontal principal stress component are selected, and the collapse pressure is obtained based on the Moore-Coulomb law in combination with the pore pressure curve, the internal friction angle curve, and the bonding strength of the rock, as the lower limit of the mud density window.

4. The pore pressure prediction method based on three-dimensional fine geostress field according to claim 3 is characterized in that: It also includes determining the mud density, which is the sum of the lower limit of the mud window and the set parameters.

5. A pore pressure prediction device based on a three-dimensional fine geostress field according to any one of claims 1 to 4, characterized in that: include: Initial structural unit, the geological structural model of the block where the target well is located is constructed by interpreting the 3D seismic wave data; The first analysis unit combines the geological structure model of the block where the target well is located and obtains the three-dimensional fine stress field numerical solution based on finite element analysis; The second analysis unit predicts the pore pressure curve and safe drilling mud density window of the target well based on seismic wave data and three-dimensional fine stress field numerical solution.

6. The pore pressure prediction device based on three-dimensional fine geostress field according to claim 5 is characterized in that: The first analysis unit comprises: Model conversion module, which constructs the corresponding finite element model according to the geological structure model of the block where the target well is located; The analysis and solution module determines the rock mechanical property parameter values ​​and horizontal tectonic stress coefficients, applies various loads and boundary conditions to the finite element model, and obtains a three-dimensional precise numerical solution of the geostress field.

7. The pore pressure prediction device based on three-dimensional fine geostress field according to claim 5 or 6, characterized in that: The second analysis unit comprises: The pore pressure prediction module extracts the acoustic wave duration data based on the seismic wave data; extracts the overburden formation pressure based on the three-dimensional fine geostress field numerical solution; combines the acoustic wave duration data and the overburden formation pressure to obtain the pore pressure of each point on the target well trajectory and form the pore pressure curve of the target well; The mud window selection module analyzes the numerical solution of the three-dimensional fine stress field and selects the minimum horizontal principal stress component as the upper limit of the mud density window; the maximum horizontal principal stress component and the minimum horizontal principal stress component are selected, and the collapse pressure is obtained based on the Moore-Coulomb law in combination with the pore pressure curve, the internal friction angle curve, and the bonding strength of the rock as the lower limit of the mud density window.

8. A storage medium, characterized in that: The storage medium stores a computer program that can be read by a computer, and the computer program is configured to execute the pore pressure prediction method based on a three-dimensional fine stress field as claimed in any one of claims 1 to 4 when running.

9. An electronic device, characterized in that: It comprises a processor and a memory, wherein a computer program is stored in the memory, and the computer program is loaded and executed by the processor to implement the pore pressure prediction method based on a three-dimensional fine stress field as described in any one of claims 1 to 4.

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