Search

CN-121993043-A - Casing running method and effect evaluation method based on casing thread safety

CN121993043ACN 121993043 ACN121993043 ACN 121993043ACN-121993043-A

Abstract

The invention relates to the technical field of oil and gas well drilling and completion engineering construction design, in particular to a casing running method and an effect evaluation method based on casing thread safety, comprising the steps of predicting the maximum friction of casing running, the bending position of the casing and the bending degree of the casing, and determining the hanging weight of the casing at a wellhead; the method comprises the steps of determining the relation between the bending degree of a wellhead casing and an applied axial force, determining the maximum impact value which can be generated when the wellhead casing is quickly lowered when meeting resistance, determining the safe maximum speed value of the casing lowering, lowering the wellhead casing at a speed which is not greater than the safe maximum speed value until the wellhead casing cannot be lowered continuously when meeting resistance, lifting the wellhead casing 20m at a speed which is not greater than the safe maximum speed value v, lowering the casing for 3-5m, starting a pump at the ground, enabling high-pressure circulating drilling fluid to enter the casing to be lowered, continuing lowering the wellhead casing at a speed which is not greater than the safe maximum speed value v until the wellhead casing is lowered for 8-10m, stopping the pump at the ground, and continuing lowering the wellhead casing. By the running method and the effect evaluation method, the running safety of the sleeve is ensured.

Inventors

  • YANG XIAOFENG
  • WANG PEIFENG
  • GAO YONGWEI
  • XU CHAOYANG
  • LI YANZE
  • CHEN CAIZHENG
  • LI XIAOLI
  • ZHAO WENZHUANG
  • GUO BAILI
  • SHI CHONGDONG

Assignees

  • 中国石油天然气集团有限公司
  • 中国石油集团川庆钻探工程有限公司

Dates

Publication Date
20260508
Application Date
20241105

Claims (10)

  1. 1. A casing running method based on casing thread safety is characterized by comprising the following steps: s 1 , predicting the maximum friction of the casing, the bending position of the casing and the corresponding bending degree of the casing by collecting field data, and determining the hanging weight m of the wellhead casing; S 2 , selecting a corresponding wellhead sleeve to perform a simulation experiment of bending thread seal fatigue failure in a horizontal well environment sleeve, and determining the relation between the bending degree of the wellhead sleeve and the applied axial force; S 3 , determining an applied axial force F according to the predicted sleeve bending degree, and determining a maximum impulse value E which can be generated when the wellhead sleeve is quickly lowered when meeting resistance; s 4 , determining a safe maximum speed value v of casing running: S 5 , smearing sleeve thread sealing grease according to requirements, and screwing the sleeve thread on a wellhead according to required torque, wherein the wellhead sleeve is put in at a speed not greater than a safe maximum speed value v until the wellhead sleeve can not be put in continuously when meeting resistance, S 6 , lifting the sleeve 20m at the wellhead, and putting in the sleeve at a speed not greater than the safe maximum speed value v for 3-5m; S 7 , starting a pump on the ground, and enabling high-pressure circulating drilling fluid to enter a sleeve to descend; S 8 , continuing to run in the wellhead casing at a speed not greater than a safe maximum speed value v until the wellhead casing is run in for 8-10m, and stopping the pump on the ground; S 9 , circulating hydraulic force disappears, and the wellhead casing continues to descend; S 10 , if the wellhead casing cannot continue to be lowered when meeting the blockage, repeating S 7 ～S 9 until the casing is completely lowered.
  2. 2. The method for setting a sleeve based on the safety of the sleeve thread according to claim 1, wherein the method for determining the maximum impulse value E is as follows: E=F*α Where F is the applied axial force and α is the scale factor.
  3. 3. A casing running method based on casing thread safety according to claim 2, wherein the casing running speed is 0.5-0.6m/s.
  4. 4. A casing running method based on casing thread safety as claimed in claim 3, wherein the wellhead casing sling weight m is greater than the predicted maximum casing running friction.
  5. 5. A casing running method based on casing thread safety according to claim 3, wherein the maximum friction of running the casing, the bending position of the casing and the bending degree of the casing are predicted by finite element analysis in step S 1 .
  6. 6. The method of casing running based on casing thread safety as claimed in claim 3, wherein the field data in step S 1 includes the real drilling track of the well bore, the formation, the reduced diameter section, the expansion rate of the well bore, and the distribution of the well-dredging section.
  7. 7. The method for setting a sleeve based on the thread safety of the sleeve as recited in claim 3, wherein the step S 2 is further used for determining the maximum bending number of the sleeve, and the lifting and setting number of the same position of the sleeve is controlled to be smaller than the maximum bending number of the sleeve in the setting process.
  8. 8. The method for running a casing based on casing thread safety according to claim 2, wherein the scale factor alpha has a value of 85%.
  9. 9. The method for evaluating the effect of the casing running method based on casing thread safety according to any one of claims 1 to 8 is characterized in that well cementation pressure test is carried out, and if the pressure drop is smaller than a rated value within 30 minutes, the casing thread seal is proved to be qualified.
  10. 10. The method for evaluating the effect of the casing running method based on casing thread safety according to claim 9, wherein the rated value is 0.5MPa if the well cementation pressure test is 35 MPa.

Description

Casing running method and effect evaluation method based on casing thread safety Technical Field The invention relates to the technical field of oil and gas well drilling and completion engineering construction design, in particular to a casing running method and an effect evaluation method based on casing thread safety. Background With the development of well drilling technology with a complex structure, the difficulty of a conventional casing running mode is high due to the fact that well inclination angle and azimuth angle change along with well depth, the casing running difficulty can be effectively solved by the aid of the rotary casing running technology, engineering difficulty is related to friction resistance in the process of rotating casing running, and the friction resistance is related to surface roughness of the casing, roughness of a well wall, bending conditions in the well, borehole track change and casing running speed. In the existing horizontal well, the horizontal section is often long, so that the abrasion resistance of the casing is large, and the potential safety hazard of the casing is present. At present, a floating casing running technology is adopted, namely when a wellhead runs a casing, two special joints are connected between casing strings of the horizontal section, so that slurry is not filled in the casing between the two joints, and only air is inside, so that the casing of the horizontal section is in the running process, and the casing of the horizontal section is easy to run because no slurry is inside the casing of the horizontal section only air, so that the weight is reduced, and the abrasion resistance is reduced. However, the floating casing running technology has higher cost, and in use, when the floating coupling circulation treatment must be opened due to the continuous accumulation of sand beds in the horizontal section shaft, the horizontal section casing loses the effect of continuous floating along with the discharge of air in the casing, and the friction of the continuous casing running is obviously increased, so that the continuous running difficulty is higher. And the floating coupling nipple joint is frequently prevented from opening on site, so that production is affected. Aiming at the field safety casing, firstly, aiming at the complex geological structure of the region and the large formation occurrence variation range, the borehole track is complex, the water-to-vertical ratio is large and the borehole cleanliness is poor, so that the efficient casing production of the ultra-long horizontal section horizontal well faces great technical challenges. Secondly, aiming at analyzing the influence of factors such as borehole track change, borehole cleaning control, borehole wall stability, centralizer and the like on the safe running of the ultra-deep long horizontal well casing, and establishing a downhole friction real-time monitoring model by combining comprehensive logging data. And thirdly, combining actual measurement data based on the block shale gas horizontal well casing running site, comprehensively utilizing a corrected three-dimensional soft rod tubular column friction resistance calculation model and a data statistics analysis method, and analyzing key factors such as a centralizer, borehole curvature, well deviation, well diameter, friction resistance coefficient and the like. The research result shows that ① accumulated borehole curvature can more intuitively reflect the influence degree of casing running friction compared with borehole curvature, when the accumulated borehole curvature is larger than 3.7 degrees/30 m, casing running friction begins to increase rapidly, so that frequent adjustment of borehole tracks is needed to be avoided for horizontal wells with larger borehole curvature, casing running difficulty is reduced, ② borehole diameter variation coefficient can accurately describe the variation amplitude of the borehole diameter along the horizontal borehole direction, and for horizontal wells with complicated geological conditions and serious borehole diameter shrinkage and collapse, prediction accuracy can be effectively improved by evaluating the influence of casing running friction through statistical analysis of the borehole diameter variation coefficient, the borehole diameter variation coefficient is smaller than 2%, the casing running friction influence is smaller, the borehole diameter variation coefficient is larger than or equal to 2%, and the casing running friction influence is larger. And fourthly, starting from the actual stress of the sleeve at the bending section, obtaining a calculation model of the maximum borehole curvature allowed by the sleeve under various tension conditions based on the effective stress. And analyzing various working conditions in the casing running process, wherein the analysis result considers that the casing is lifted to be the most dangerous working condition, and the maximum borehole