CN-117569795-B - Intensity-homogenizing high-extrusion-resistance oil sleeve and design and manufacturing method thereof

CN117569795BCN 117569795 BCN117569795 BCN 117569795BCN-117569795-B

Abstract

The invention discloses a high-extrusion-resistance oil sleeve with uniform strength and a design and manufacturing method thereof. A design method of a high-extrusion-resistance casing with uniform strength comprises the following steps of S100, analysis and verification of an extrusion mechanism of the casing, S110-130, preparation of a casing sample, S111-113, S111 and geometric dimension detection, wherein the sample is taken from the existing casing specification meeting the API extrusion-resistance requirement, the length of the sample is more than 8 times of the nominal outer diameter, and the middle section of the length of the sample is taken as a reference. Compared with the prior art, the invention produces the high-extrusion-resistance oil jacket pipe on the basis of the extrusion mechanism research, and the equal-strength high-extrusion-resistance jacket pipe test is verified that the geometric dimension control and the residual stress are obviously changed to be larger than the control values required by the conventional high-extrusion-resistance jacket pipe.

Inventors

LI JINGMIN
XIAO YONGZHONG
TANG YI
ZHAO MING
WANG JIANDONG

Assignees

林州凤宝管业有限公司

Dates

Publication Date: 20260512
Application Date: 20231116

Claims (3)

1. A design method of a high-extrusion-resistance casing pipe with uniform strength is characterized by comprising the following steps: s100, analyzing and verifying an oil sleeve collapse mechanism, wherein the method comprises the steps of S110-130; S110, preparing an oil sleeve sample, which comprises the following steps of S111-113: S111, geometric dimension detection, namely taking a sample from the existing oil casing specification designed to meet the API anti-extrusion requirement, wherein the length of the sample is more than 8 times of the nominal outer diameter, detecting the geometric dimension of the pipe body at equal intervals by taking the diameter D of the pipe body as a detection interval to two ends respectively by taking the middle section of the length of the sample as a reference, and detecting at least 5 sections, wherein each section is at least 4 diameters and 8 wall thickness points; Analyzing the geometric dimension after detection, wherein the ovality and the uneven wall thickness of each section are shown in the formulas 1 and 2; OV=100 (Dmax-Dmin)/Dave (formula 1) Wherein, OV is ovality of each section with the unit of; dmax, maximum value of measured diameter per section; dmax, minimum value of measured diameter per section; dave, average value of measured diameter of each section; ec=100 (tcmax-tcmin)/tcave (formula 2) EC, the wall thickness unevenness of each section is expressed in units of; tcmax maximum values of wall thickness per section measurement; tcmin minimum measured wall thickness per section; tcave average wall thickness per section; s112, detecting residual stress of a plurality of pipe bodies, namely detecting macroscopic residual stress of the pipe bodies by adopting a circular cutting method, taking the pipe bodies with the length being more than 2.5 times of the diameter, measuring 3 diameter positions and 6 wall thickness points on the pipe bodies, and detecting the geometric dimensions of the pipe bodies according to the following residual stress calculation method; ; Wherein, the The average outer diameter of the oil sleeve after cutting; The average outer diameter of the oil sleeve before cutting; sigma, residual stress of the pipe body; E, material elastic modulus; t, average measuring point wall thickness; μ, poisson's ratio of material; d1, D2 and D3, measuring the diameter of the point; S113, detecting mechanical properties of a pipe body material, namely taking a plate-shaped tensile sample from four quadrants on the pipe body, detecting the mechanical properties of the material, and detecting the tensile yield strength, the tensile strength and the elongation of the material, wherein the mechanical properties of the pipe body material change in the production rolling, heat treatment and straightening processes can be reflected through the mechanical properties of the material in the four quadrants; s120, a pipe body real object extrusion test comprises the steps of S121-122; s121, an external extrusion destroying test, namely placing the pipe body into an external extrusion destroying container, adding external pressure until the pipe body is extruded and deformed, and recording a pressure test curve; s122, geometric dimension detection after an external extrusion destroying test, namely detecting the outer diameter and the wall thickness of a test sample after the extrusion destroying failure; The detection result shows that the middle position of the tube body is subjected to the most serious extrusion failure deformation, and simultaneously shows that the extrusion is firstly subjected to plastic deformation under external pressure from the middle position of the sample tube body until the extrusion is completely failed; S130, analyzing an oil sleeve extrusion mechanism, wherein the analysis comprises the steps of S131-133; S131, finite element modeling, namely modeling the geometric dimension according to the original outer diameter and the wall thickness of the maximum deformation position of the extruded sample in a physical test, dividing the model into four quadrants, and endowing the mechanical property of the material according to the mechanical property of the material in the actually measured four quadrants; modeling, namely considering pipe end clamping and fixing effects according to the four-quadrant actual measurement stress-strain curve, the geometric dimension and the length of the oil casing material by more than 10 times of the outer diameter of the pipe body; S132, a finite element simulation external extrusion destroying process, namely applying the residual hoop stress actually measured by the sample in the step S112 to the pipe body, then externally pressing until the extrusion deformation of the pipe body is consistent with the actually measured maximum deformation size after full-size physical test extrusion, comparing the relative error of the external extrusion load and the physical test extrusion load with the finite element calculation, and verifying whether the finite element calculation method is accurate and reliable; The finite element analysis result of the oil casing extrusion process simulates extrusion morphology and compares with actual test extrusion morphology, namely, the extrusion morphology of the calculation analysis is consistent with the extrusion morphology of a real object, the calculated external pressure change curve of the extrusion process is compared with the actual extrusion process curve, the external pressure change trend of the extrusion process is consistent, and the relative error between the calculated value of the maximum external pressure value of the extrusion process and the test value is 0.07 percent, which indicates that the calculation of the simulated oil casing extrusion process is accurate and reliable; S133, analysis of a squeeze leading factor, namely, analysis of a mechanism in a squeeze process of the oil casing shows that when the anti-squeeze bearing external pressure of the oil casing reaches the maximum value: 1) The inner wall of quadrant 1 with the minimum yield strength yields first; 2) Quadrant 2 has the greatest plastic strain where the wall thickness is small; 3) Firstly, the diameter position where the inner wall yields has the maximum outer diameter, and the ovality is increased by 2.14 times compared with the original value, and the wall thickness unevenness is unchanged compared with the original value; 4) After the oil sleeve is finally subjected to severe extrusion plastic deformation, the materials at the major axis position and the minor axis position with the largest ellipse yield, and the severe plastic deformation exceeding the material yield strength measured by the materials exceeds the material yield plastic strain point by 0.65%; the rest positions are not subjected to yielding and obvious plastic deformation; s200, design of high-extrusion-resistance oil sleeve Based on the analysis, the extrusion resistance can be obviously improved by improving the yield strength of the material of the oil sleeve along the circumference, and the extrusion resistance can also be improved by controlling the uniformity of the strength of the material of the oil sleeve along the circumference, so that the high extrusion resistance oil sleeve is designed according to the analysis, and specifically, the method comprises the following steps: Controlling the ovality of geometric dimension to be less than or equal to 0.8%, the uneven wall thickness to be less than or equal to 10%, the residual compressive stress to be less than or equal to 200MPa, and the minimum wall thickness to be more than 90% of the specified nominal wall thickness; s300, verifying and evaluating high-oil-squeezing-resistance sleeve On the basis of the extrusion mechanism research, a high-extrusion-resistance sleeve is produced, and the equal-strength high-extrusion-resistance sleeve test is carried out to verify that the geometric dimension control and the residual stress are all obviously changed and are larger than the control value required by the conventional high-extrusion-resistance sleeve.
2. A manufacturing method of the high-extrusion-resistance oil casing pipe with uniform strength is characterized in that the design method of the high-extrusion-resistance oil casing pipe with uniform strength is used, product parameters obtained by the method are used as requirements, in manufacturing, a pipe body material is uniform along the circumferential mechanical property by controlling a heat treatment process, the extrusion-resistance strength of the pipe body is improved, and the high-extrusion-resistance performance of the oil casing pipe can be realized by controlling the material strength uniformity.
3. A high-strength-uniformity high-extrusion-resistance sleeve, characterized in that the sleeve is manufactured by the manufacturing method of the high-strength-uniformity high-extrusion-resistance sleeve as claimed in claim 2.

Description

Intensity-homogenizing high-extrusion-resistance oil sleeve and design and manufacturing method thereof Technical Field The invention belongs to the technical field of petroleum and natural gas exploitation, and particularly relates to a high-extrusion-resistance sleeve with uniform strength and a design method thereof. Background Deep wells and ultra-deep wells in the petroleum industry are increasingly increased, and the greater the external pressure of a ground layer is along with the increase of the well depth, the higher the external pressure bearing capacity of a well shaft is required, namely the higher the extrusion resistance of an oil casing is required. The typical representation of the oil casing extrusion strength design method is an extrusion strength calculation formula proposed by API5C3 at present, and the extrusion strength of the pipe body is determined according to the nominal yield strength corresponding to the steel grade of the oil casing pipe material and the ratio of the nominal outer diameter of the pipe body to the wall thickness, and is called as the API extrusion strength. The anti-extrusion strength of the pipe body is improved by researching and controlling the parameters of influencing factors, and the anti-extrusion strength of the pipe body, which is higher than the specified value of the API, is called as a high anti-extrusion oil sleeve. The main factors of impact on the extrusion resistance of the oil casing given in appendix F of API5C3 are the ovality of the casing, the uneven wall thickness, the residual compressive stress and the straightening process of the oil casing. The existing high-extrusion-resistance sleeve design method has the following problems: 1) According to the API extrusion strength calculation method, in order to improve the extrusion strength of the pipe body, the main measures are to improve the yield strength of materials and the wall thickness of the pipe body, reduce the ratio of the outer diameter to the wall thickness, and cause the increase of the dead weight of the oil sleeve and the increase of the steel grade, thereby increasing the use cost. 2) The factor affecting the extrusion strength of the API 5C3 annex F is a KT extrusion strength calculation formula based on the regression of the statistical result of the actual extrusion test data of the oil sleeve, and the factors are based on ovality, uneven wall thickness, residual compressive stress and oil sleeve straightening process of the geometric dimension of the pipe body, so that the rejection rate in actual production is improved and the production and manufacturing cost is remarkably improved due to the strict control of the geometric dimension of the pipe body. The extrusion mechanism analysis of the oil casings with different outer diameters and wall thicknesses is not carried out, specific targeted measures are not carried out, the statistical formula cannot reflect the irregularity of the geometric dimension of the section of the oil casing, the oil casing is treated as an ideal ellipse, and the actual production of the oil casing cannot be guided. 3) The invention relates to a rare earth-containing low-cost high-collapse-resistance petroleum casing pipe and a manufacturing method thereof, and the petroleum casing pipe has the characteristics of low production cost, high strength and toughness performance matching, uniform and fine tissue, low residual stress and high collapse resistance. The mechanism of high extrusion resistance of the oil casing is not disclosed, but the chemical composition of the oil casing is changed, and the extrusion resistance of the oil casing is not verified by a real object. 4) Patent application number CN201910222980, a corrosion-resistant high-extrusion-resistant petroleum casing pipe and a preparation method thereof. The oil casing is characterized in that the external diameter ovality of the oil casing is less than or equal to 0.5 percent D, the wall thickness unevenness is less than or equal to 15 percent t, and the residual stress of the pipe body is less than or equal to 100MPa, wherein D is the nominal diameter of the oil casing, the unit is mm, and t is the nominal wall thickness of the oil casing, and the unit is mm. The extrusion resistance is improved by controlling the geometric dimension precision and the residual stress based on the extrusion resistance influencing factors proposed by the standard, so that the production cost is remarkably improved, and the method has no innovation and contribution to the high extrusion resistance design method. According to the analysis, the existing high-extrusion-resistance oil casing design method is characterized in that 1 the high-extrusion-resistance oil casing is designed based on the influence factors and the extrusion-resistance calculation formula proposed by the API standard, and 2 the chemical components of the oil casing material are controlled, so that the production cost is reduced. In t