CN-122020987-A - Method for optimizing directional perforation point positions of horizontal well of crushed soft coal seam gas roof

CN122020987ACN 122020987 ACN122020987 ACN 122020987ACN-122020987-A

Abstract

The application relates to a method for optimizing directional perforation points of a horizontal well of a crushed soft coal layer gas roof, which belongs to the field of coal bed gas exploitation and comprises the steps of obtaining coal bed gas roof rock mechanical property data and coal rock property data of a known area, constructing a three-dimensional geomechanical model of the target area according to roof and floor of the target area, coal bed test well data, three-dimensional seismic structure data, coal bed gas roof rock mechanical property data and coal rock property data, obtaining drilling test data, determining candidate perforation intervals according to the drilling test data, determining a plurality of candidate perforation points in the candidate perforation intervals, and screening the candidate perforation points to obtain the optimized perforation points. According to the application, through the optimized selection of the perforation point positions, the problem of perforation through the casing coupling in the perforation construction process is effectively avoided, the occurrence of perforation accident rate is reduced, and the single well productivity is effectively improved.

Inventors

ZHANG TONG
ZHANG JIE
LI PENG
YANG ZHE
HU XINPENG

Assignees

中煤科工西安研究院(集团)有限公司

Dates

Publication Date: 20260512
Application Date: 20260107

Claims (9)

1. The method for optimizing the directional perforation point positions of the horizontal well of the crushed soft coal seam gas roof is characterized by comprising the following steps of: acquiring the rock mechanical property data of a coalbed methane roof and the rock property data of the coalbed methane roof in a known area; Constructing a three-dimensional geomechanical model of the target area according to the top and bottom plates of the target area, the coal seam well test data, the three-dimensional seismic structure data, the rock mechanical property data of the coal seam gas top plate and the coal rock property data; Drilling test data are acquired, wherein the drilling test data comprise horizontal well directional drilling guide track data, coalbed methane content data, drilling time data, casing setting data and well cementation data of a target area; The vertical distance between each candidate perforation point and the top boundary of the coal seam is calculated based on the three-dimensional geomechanical model of the target area; determining the distance between each perforation point after primary screening and a fault, and screening the perforation points after primary screening according to the distance to obtain a plurality of perforation points after secondary screening; performing crack extension simulation on each secondarily screened perforation point to obtain a crack extension distance; screening the perforation points after secondary screening according to the crack extension distance to obtain a plurality of perforation points after tertiary screening; And determining the minimum principal stress gradient difference of each perforation point after three times of screening, and screening the perforation point after each three times of screening according to the minimum principal stress gradient difference to obtain a plurality of optimized perforation points.
2. The method of claim 1, wherein the vertical distance of each candidate perforation point from the top boundary of the coal seam is calculated based on a three-dimensional geomechanical model of the target area using the following formula: Wherein, the In order to be a vertical distance from each other, As a safety factor, the safety factor of the device, Is the Young's modulus of the top plate, Is the minimum principal stress of the top plate, Is the minimum principal stress of the coal seam, As the weight coefficient of the tensile strength, For the tensile strength of the top plate, As a reference value for the tensile strength, Is the weight coefficient of the interface cementation, Is the coefficient of the coal-rock interface, As a reference value for the coefficient of cementing, As a basis for the amount of the offset, In order to maximize the breaking load, Is the diameter of the core, Is the thickness of the top plate.
3. The method of claim 1, wherein screening each candidate perforation point based on the vertical distance to obtain a plurality of screened perforation points comprises: And if the vertical distance is larger than the thickness of the top plate corresponding to the candidate perforation point, the candidate perforation point is reserved, otherwise, the candidate perforation point is removed.
4. The method of claim 1, wherein screening each of the first screened perforation points based on the distance to obtain a plurality of second screened perforation points comprises: If the distance is larger than a first set value, the perforation points after the primary screening are reserved, otherwise, the perforation points after the primary screening are removed.
5. The method of claim 1, wherein screening each of the secondarily screened perforation points based on the fracture propagation distance to obtain a plurality of tertiary screened perforation points comprises: and if the crack extension distance is greater than or equal to 85% of the coal seam thickness, retaining the perforation points after the secondary screening, otherwise, removing the perforation points after the secondary screening.
6. The method of claim 1, wherein screening each of the three screened perforation points according to the minimum principal stress gradient difference to obtain a plurality of optimized perforation points comprises: And if the minimum principal stress gradient difference is larger than a second set value, reserving the perforation points after the third screening, otherwise, removing the perforation points after the third screening.
7. The utility model provides a garrulous soft coal seam gas roof horizontal well directional perforation point position optimizing apparatus which characterized in that includes: The data acquisition module is used for acquiring the rock mechanical property data of the coalbed methane roof in the known area and the rock property data of the coalbed methane roof; The model construction module is used for constructing a three-dimensional geomechanical model of the target area according to the top and bottom plates of the target area, the coal seam well test data, the three-dimensional seismic construction data, the rock mechanical property data of the coal seam gas top plate and the coal rock property data; The system comprises a candidate perforation point position determining module, a candidate perforation interval determining module and a drilling and testing module, wherein the candidate perforation point position determining module is used for acquiring drilling and testing data, and the drilling and testing data comprises horizontal well directional drilling guide track data, coal bed gas content data, drilling time data, casing pipe setting data and well cementation data of a target area; The first screening module is used for calculating the vertical distance between each candidate perforation point and the top boundary of the coal seam based on the three-dimensional geomechanical model of the target area, screening each candidate perforation point according to the vertical distance, and obtaining a plurality of perforation points after primary screening; The second screening module is used for determining the distance between each perforation point after primary screening and the fault, and screening the perforation points after primary screening according to the distance to obtain a plurality of perforation points after secondary screening; The third screening module is used for carrying out crack extension simulation on each perforation point after secondary screening to obtain crack extension distance; screening the perforation points after secondary screening according to the crack extension distance to obtain a plurality of perforation points after tertiary screening; And the fourth screening module is used for determining the minimum principal stress gradient difference of the perforation points after each third screening, and screening the perforation points after each third screening according to the minimum principal stress gradient difference to obtain a plurality of optimized perforation points.
8. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program which, when executed by a processor, implements the method for optimizing the directional perforation point location of a crushed soft coal seam gas roof horizontal well according to any one of claims 1 to 6.
9. A computer program product comprising computer programs/instructions which, when executed by a processor, implement the method of optimizing the point location of oriented perforation of a horizontal well of a crushed soft coal seam gas roof as claimed in any one of claims 1 to 6.

Description

Method for optimizing directional perforation point positions of horizontal well of crushed soft coal seam gas roof Technical Field The application relates to the field of coal bed gas exploitation, in particular to a method for optimizing a directional perforation point position of a horizontal well of a crushed soft coal bed gas roof. Background Coalbed methane is an important unconventional natural gas resource, and efficient development thereof relies on establishing an effective communication channel between a well bore and a coal bed. Perforation technology plays a critical role in this process as one of the core links in completion engineering. The core purpose is to accurately penetrate the perforations in the casing (or open hole wall) and cement sheath, forming a diversion path for fluids (gas and water) from the coal seam matrix and fracture system into the wellbore. Compared with the conventional sandstone or carbonate reservoir, the coal bed has remarkable specificity, and provides unique requirements and challenges for the jet hole technology, namely relatively loose coal and rock texture, strong brittleness, low mechanical strength and easy breaking. The conventional high-hole density and deep-penetration perforation mode can cause a large amount of coal dust to be generated in a near-wellbore zone, plug pore throats and wellbores and seriously damage productivity, and a natural cutting torch (surface cutting torch and end cutting torch) network in a coal bed is extremely developed and is a main seepage channel. Perforation design requires full consideration of how to effectively communicate or extend these natural fracture systems rather than simply pursuing "hole" in tight rock. Coal rock is highly sensitive to stress changes, and improper perforation processes (such as excessive negative pressure differences or positive pressure differences) can cause instability, collapse or exacerbate stress sensitivity effects of the coal body structure, resulting in dramatic reduction of permeability and reduction of yield. Along with development of coal bed methane development technology, most coal bed methane development blocks are mainly developed at present by compounding large-scale hydraulic fracturing with long-distance horizontal wells, most coal bed methane wells are required to be subjected to hydraulic fracturing transformation (fracturing) to obtain economic productivity, and traditional coal bed methane horizontal well perforation is in direct contact with coal bed perforation, but the coal bed has low mechanical strength and strong heterogeneity, and is easy to cause out of control of crack height, sand blockage and low communication efficiency. The conventional coalbed methane roof horizontal well communicates a shaft and a coal bed channel through a conventional perforation technology, but conventional perforation point location selection often does not accord with an actual stratum structure due to high control accuracy of drilling tracks, high fluctuation of the long-distance horizontal well coal bed roof and high roof thickness non-uniformity, and a systematic point location selection standard is lacking, so that the roof and the coal bed cannot be effectively communicated, and subsequent fracturing effect fluctuation is high. Disclosure of Invention In order to overcome at least one defect in the prior art, the application provides a method for optimizing the directional perforation point positions of a horizontal well of a crushed soft coal layer gas roof. In a first aspect, a method for optimizing a directional perforation point location of a horizontal well of a crushed soft coal seam gas roof is provided, which comprises the following steps: acquiring the rock mechanical property data of a coalbed methane roof and the rock property data of the coalbed methane roof in a known area; Constructing a three-dimensional geomechanical model of the target area according to the top and bottom plates of the target area, the coal seam well test data, the three-dimensional seismic structure data, the rock mechanical property data of the coal seam gas top plate and the coal rock property data; The method comprises the steps of obtaining drilling test data, wherein the drilling test data comprise horizontal well directional drilling guide track data, coalbed methane content data, drilling time data, casing setting data and well cementation data of a target area; The vertical distance between each candidate perforation point and the top boundary of the coal seam is calculated based on the three-dimensional geomechanical model of the target area; Determining the distance between each perforation point after primary screening and the fault, and screening the perforation points after primary screening according to the distance to obtain a plurality of perforation points after secondary screening; Performing crack extension simulation on each secondarily screened perforation point to obtain a crack