CN-121997421-A - Well body structure design method of U-shaped butt joint well

CN121997421ACN 121997421 ACN121997421 ACN 121997421ACN-121997421-A

Abstract

The invention discloses a U-shaped butt-joint well structure design method which comprises the steps of firstly obtaining geological, geophysical and engineering monitoring data of a target work area, building a three-dimensional geomechanical model, accessing measurement while drilling data during drilling, updating in real time through a model self-learning module, obtaining a dynamic geomechanical model, secondly generating a preliminary well track based on the model, calculating the risk probability of the well track, generating a risk probability distribution cloud image, generating a basic well structure scheme and a standby well structure scheme by using a multi-objective optimization algorithm, setting a three-dimensional virtual target area at the upper stream of a horizontal section entering target point, dynamically adjusting the position and the form of the target area and correcting the build rate, calculating a three-dimensional dynamic safe drilling window, finally inputting the scheme, the track and the window into an integrated design platform for coupling simulation, outputting an optimal scheme, feeding real drilling data back to the steps, and starting the next round of model updating optimization.

Inventors

ZOU YANRONG
GAO XIAORONG
LIU BIN
WANG PENGTAO
SUN CAIXIA
LU XINGCHEN
ZHAO YUXUAN
REN XIAOQING
LU CHAOPENG

Assignees

中石化绿源地热能(陕西)开发有限公司

Dates

Publication Date: 20260508
Application Date: 20260123

Claims (9)

1. The method for designing the structure of the U-shaped butt joint well body is characterized by comprising the following steps of: S1, obtaining geological exploration data, geophysical measurement data and engineering monitoring data of a target work area, establishing a three-dimensional geomechanical model capable of quantitatively representing a stratum mechanical environment, accessing measurement while drilling data in a drilling process, and updating the three-dimensional geomechanical model in real time through a model self-learning module to obtain a dynamic geomechanical model; S2, generating a preliminary well track based on the dynamic geomechanical model, and calculating a well wall instability risk probability, a pressure abnormality risk probability and a butt joint failure risk probability along the preliminary well track to generate a risk probability distribution cloud picture; s3, setting a three-dimensional virtual target area at the upstream of an entry target point of the horizontal section of the butt joint well, dynamically adjusting the space position and the geometric form of the three-dimensional virtual target area based on the dynamic geomechanical model and real-time measurement while drilling data, and correcting the slope of the well track according to the space position and the geometric form; S4, calculating a three-dimensional dynamic safety drilling window which is coupled with the current borehole track and has a non-circular cross section based on the updated dynamic geomechanical model; And S5, inputting the basic well structure scheme, the standby well structure scheme, the corrected well track and the three-dimensional dynamic safe drilling window into an integrated design platform for coupling simulation, outputting an optimal well structure design scheme based on a simulation result, and feeding real drilling data back to the step S1 to start model updating and optimization of the next round.
2. The method for designing the well body structure of the U-shaped butt joint well according to claim 1, wherein the working method of the model self-learning module is as follows: and comparing the geological parameters and engineering parameters in the measurement while drilling data with model predicted values, and automatically correcting the stratum pressure, the ground stress direction and the rock mechanical parameters in the dynamic geomechanical model through a preset algorithm.
3. The method for designing the well structure of the U-shaped butt joint well according to claim 2, wherein the preset algorithm is a back propagation algorithm in machine learning or an ensemble learning algorithm.
4. The method for designing the well structure of the U-shaped butt joint well according to claim 1, wherein the well wall instability risk probability is calculated based on joint probability distribution of a concentration coefficient and a rock strength parameter of the well Zhou Yingli, the pressure anomaly risk probability is calculated based on statistical characteristics of formation pressure monitoring data, and the butt joint failure risk probability is calculated by simulating spatial relation between a real drilling track ellipsoid and a target area.
5. The method for designing the well structure of the U-shaped butt joint well according to claim 1, wherein the optimization targets of the multi-target optimization algorithm comprise the total cost, the estimated drilling period and the comprehensive risk probability of the well structure, and the decision variables comprise the running depth of each layer of casing and the drilling fluid density window.
6. The method of claim 1, wherein in step S3, the logic for dynamically adjusting the three-dimensional virtual target area comprises: when the drilling of the high-plasticity rock stratum is identified, the longitudinal length of the three-dimensional virtual target area is increased; when the drilling fault is identified, the cross section of the three-dimensional virtual target area is adjusted to be an ellipse along the fault trend; And when the detected change of the direction of the ground stress exceeds a preset threshold value, pre-correcting the central line azimuth of the three-dimensional virtual target area.
7. The method according to claim 1, wherein in step S4, the non-circular cross section of the three-dimensional dynamic safety drilling window is elliptical or racetrack, and the boundary is determined by the fracture pressure, collapse pressure and real-time calculated well cleaning requirement of the stratum.
8. The method of claim 7, wherein the upper limit of the drilling fluid density of the three-dimensional dynamic safety drilling window is determined by subtracting a predetermined safety margin from the formation fracture pressure equivalent density; The lower limit value of the drilling fluid density of the three-dimensional dynamic safe drilling window is determined by comparing the two values, namely, the equivalent density of the formation collapse pressure plus a preset safety margin, and the minimum equivalent density required by well cleaning is calculated according to the real-time well inclination angle, and the larger value of the two values is finally taken.
9. The method of claim 1, wherein in step S5, the parameters of the coupling simulation include casing string strength, borehole trajectory curvature, drilling fluid performance, completion string running feasibility, tubing fluid carrying capacity in production phase, and thermal stress effects.

Description

Well body structure design method of U-shaped butt joint well Technical Field The invention relates to the technical field of directional drilling, in particular to a method for designing a well body structure of a U-shaped butt joint well. Background Along with the promotion of shale gas/coal bed gas development to deep and complex stratum and the improvement of accurate communication demand of underground gas storage well pattern, the U-shaped butt joint well becomes the key technology in the field of underground engineering because of being capable of realizing well cross-well shaft communication and optimizing resource development efficiency. However, the conventional U-shaped butt joint well structure design method is limited by technical concepts and tools, and is difficult to adapt to complex stratum conditions. The traditional design method relies on a static three-dimensional geological model constructed before the construction of the real drill, dynamic changes of stratum conditions (such as unknown faults, high-pressure abnormal strata and high-plasticity strata during the drilling process) are not considered, the model cannot be accessed into measurement while drilling (MWD/LWD) data in real time for correction, so that the ground stress parameters, the rock mechanical properties and the real drill stratum deviate obviously, further borehole track deviation is caused, the butting precision is reduced, the generation scheme is single, and the scheme fault tolerance is poor. Therefore, it is necessary to provide a method for designing the well structure of the U-shaped docking well to solve the above-mentioned problems in the prior art. Disclosure of Invention In order to achieve the above purpose, the invention provides a method for designing a well body structure of a U-shaped butt joint well, which comprises the following steps: S1, obtaining geological exploration data, geophysical measurement data and engineering monitoring data of a target work area, establishing a three-dimensional geomechanical model capable of quantitatively representing a stratum mechanical environment, accessing measurement while drilling data in a drilling process, and updating the three-dimensional geomechanical model in real time through a model self-learning module to obtain a dynamic geomechanical model; S2, generating a preliminary well track based on the dynamic geomechanical model, and calculating a well wall instability risk probability, a pressure abnormality risk probability and a butt joint failure risk probability along the preliminary well track to generate a risk probability distribution cloud picture; s3, setting a three-dimensional virtual target area at the upstream of an entry target point of the horizontal section of the butt joint well, dynamically adjusting the space position and the geometric form of the three-dimensional virtual target area based on the dynamic geomechanical model and real-time measurement while drilling data, and correcting the slope of the well track according to the space position and the geometric form; S4, calculating a three-dimensional dynamic safety drilling window which is coupled with the current borehole track and has a non-circular cross section based on the updated dynamic geomechanical model; And S5, inputting the basic well structure scheme, the standby well structure scheme, the corrected well track and the three-dimensional dynamic safe drilling window into an integrated design platform for coupling simulation, outputting an optimal well structure design scheme based on a simulation result, and feeding real drilling data back to the step S1 to start model updating and optimization of the next round. Preferably, the working method of the model self-learning module is as follows: and comparing the geological parameters and engineering parameters in the measurement while drilling data with model predicted values, and automatically correcting the stratum pressure, the ground stress direction and the rock mechanical parameters in the dynamic geomechanical model through a preset algorithm. Preferably, the preset algorithm is a back propagation algorithm in machine learning or an ensemble learning algorithm. The well wall instability risk probability is calculated based on joint probability distribution of a well Zhou Yingli concentration coefficient and a rock strength parameter, the pressure abnormality risk probability is calculated based on statistical characteristics of formation pressure monitoring data, and the butt joint failure risk probability is calculated by simulating a spatial relationship between a real drilling track ellipsoid and a target area. Preferably, the optimization objectives of the multi-objective optimization algorithm include total cost of the well structure, estimated drilling period, and comprehensive risk probability, and the decision variables include running depth of each layer of casing and drilling fluid density window. Preferably, in