CN-122021372-A - Pressure while drilling monitoring method for stratum with different lithology

Abstract

The invention discloses a pressure while drilling monitoring method for different lithology strata, which utilizes three stratum pressure calculation methods applicable to different lithology strata to calculate stratum pressures of a target well and an adjacent well respectively, obtains weighting coefficients of the three calculation methods according to the measured stratum pressures of the adjacent well and the calculated stratum pressures of the adjacent well, and utilizes the weighting coefficients to carry out weighted calculation on the stratum pressures of the target well obtained by the three calculation methods to obtain the stratum pressure while drilling of the target well. The method can monitor the formation pressure with different lithologies in the process of drilling, can achieve higher accuracy in monitoring the formation pressure with different lithologies, improves the applicability and accuracy of monitoring the formation pressure while drilling, and solves the problems that the monitoring of the pressure while drilling or the monitoring accuracy is too low for complex lithologies can not be realized. In the while-drilling process, if the stratum pressure is abnormal, early warning can be performed in time, so that the well control risk is reduced, and sufficient safety guarantee is provided for high-speed drilling.

Inventors

• YAN WEIJUN
• JIANG HAI
• LI WEN
• Wen Zhanhe
• WANG XIANZHENG
• ZHAO DAYONG
• ZHAO BO
• Dai Zhanjun
• TIAN WEIZHI
• YAN CHANGQING
• GUAN YUXIN
• WU YAN
• ZHU GUANGYU
• ZHU YONGHUAN
• FU SHAOSHUAI
• ZHANG NING

Assignees

• 中国石油集团长城钻探工程有限公司
• 中国石油天然气集团有限公司

Dates

Publication Date

20260512

Application Date

20241108

Claims (10)

1. 1. A method for monitoring pressure while drilling in different lithologic formations, comprising the steps of: S1, collecting the overburden formation pressure, the hydrostatic formation pressure and the drilling fluid density of the area where the target well is located; s2, calculating a dc index, a dc index trend, a sigma index trend, a compensation adjustment coefficient, an MSE trend and an Eton index correction value of the target well; S3, calculating to obtain the dc index formation pressure of the target well according to the overburden formation pressure, the formation hydrostatic pressure, the dc index and the dc index trend of the target well, calculating to obtain the sigma index formation pressure of the target well according to the drilling fluid density, the sigma index trend and the compensation adjustment coefficient of the target well, and calculating to obtain the MSE formation pressure of the target well according to the overburden formation pressure, the formation hydrostatic pressure, the MSE trend and the Eton index correction value of the target well; s4, collecting the overburden formation pressure, the hydrostatic formation pressure and the drilling fluid density of the area where the adjacent well of the target well is located; s5, calculating the dc index, the dc index trend, the sigma index trend, the compensation adjustment coefficient, the MSE trend and the Eton index correction value of the adjacent well; S6, calculating to obtain the dc index formation pressure of the adjacent well according to the overburden formation pressure, the formation hydrostatic pressure, the dc index and the dc index trend of the adjacent well, calculating to obtain the sigma index formation pressure of the adjacent well according to the drilling fluid density, the sigma index trend and the compensation adjustment coefficient of the adjacent well, and calculating to obtain the MSE formation pressure of the adjacent well according to the overburden formation pressure, the formation hydrostatic pressure, the MSE trend and the Eton index correction value of the adjacent well; S7, calculating to obtain a weighting coefficient of the dc index formation pressure of the adjacent well according to the dc index formation pressure of the adjacent well and the measured formation pressure of the adjacent well, calculating to obtain a weighting coefficient of the sigma index formation pressure of the adjacent well according to the sigma index formation pressure of the adjacent well and the measured formation pressure of the adjacent well, and calculating to obtain a weighting coefficient of the MSE formation pressure of the adjacent well according to the MSE formation pressure of the adjacent well and the measured formation pressure of the adjacent well; And S8, carrying out weighted calculation on the dc index formation pressure of the target well, the sigma index formation pressure of the target well and the MSE formation pressure of the target well according to the dc index formation pressure weighted coefficient of the adjacent well, the sigma index formation pressure weighted coefficient of the adjacent well and the MSE formation pressure weighted coefficient of the adjacent well, and calculating to obtain the formation pressure while drilling of the target well.
2. 2. The method of monitoring pressure while drilling for use in different lithologic formations of claim 1, wherein in step S3, the dc-index formation pressure of the target well is calculated from the overburden formation pressure, the hydrostatic formation pressure, the dc index and the dc-index trend of the target well, specifically by the following formula: The method comprises the steps of obtaining a target well, wherein PP dc represents the dc index stratum pressure of the target well, the unit is g/cm 3 , OBG represents the overburden stratum pressure of the target well, the unit is g/cm 3 ;PP N represents the stratum hydrostatic pressure of the target well, the unit is g/cm 3 , dc represents the dc index of the target well and has no dimension, and dcn represents the dc index trend value of the target well and has no dimension.
3. 3. The method for monitoring pressure while drilling for different lithologic formations according to claim 2, wherein in step S3, the sigma index formation pressure of the target well is calculated according to the drilling fluid density, the sigma index trend and the compensation adjustment coefficient of the target well, specifically by the following formula: The method comprises the steps of obtaining a target well, wherein PP sigma represents sigma index stratum pressure of the target well, the unit of g/cm 3 ;ρ Drilling fluid represents drilling fluid density of the target well, the unit of g/cm 3 , sigma represents sigma index of the target well, dimensionless, sigma' represents sigma index trend value of the target well, dimensionless, h represents well depth, the unit of m, and n represents compensation adjustment coefficient of the target well.
4. 4. The method of monitoring pressure while drilling for different lithologic formations of claim 3, wherein in step S3, the MSE formation pressure of the target well is calculated according to the overburden formation pressure, the hydrostatic formation pressure, the MSE trend, and the eaton index correction value of the target well, specifically by the following formula: PP MSE ＝OBG-(OBG-PP N )(MSE/MSEN) X (4) The MSE of the target well is expressed by PP MSE , the unit is g/cm 3 , the unit is MPa, the unit is MSE trend of the target well is expressed by MSEN, the unit is MPa, and the X is the Eton index correction value of the target well and is dimensionless.
5. 5. The method of monitoring pressure while drilling for use in different lithologic formations according to claim 1, wherein in step S6, the dc index formation pressure of the adjacent well is calculated according to the overburden formation pressure, the hydrostatic formation pressure, the dc index and the dc index trend of the adjacent well, specifically by the following formula: The method comprises the steps of obtaining a PP dc Adjacent well , wherein the PP dc Adjacent well represents the dc index stratum pressure of an adjacent well, the unit is g/cm 3 ;OBG Adjacent well represents the overburden stratum pressure of the adjacent well, the unit is g/cm 3 ;PP N Adjacent well represents the stratum hydrostatic pressure of the adjacent well, the unit is g/cm 3 ;dc Adjacent well represents the dc index of the adjacent well and has no dimension, and the dcn Adjacent well represents the dc index trend value of the adjacent well and has no dimension.
6. 6. The method for monitoring pressure while drilling for different lithologic formations according to claim 5, wherein in step S6, the sigma index formation pressure of the adjacent well is calculated according to the drilling fluid density, the sigma index trend and the compensation adjustment coefficient of the adjacent well, specifically by the following formula: The method comprises the steps of obtaining a standard value of a drilling fluid, wherein PP sigma Adjacent well represents the sigma index formation pressure of an adjacent well, the unit of g/cm 3 ;ρ Drilling fluid for adjacent well represents the drilling fluid density of the adjacent well, the unit of g/cm 3 ;sigma Adjacent well represents the sigma index of the adjacent well, the standard value is dimensionless, sigma' Adjacent well represents the sigma index trend value of the adjacent well, the standard value is dimensionless, h Adjacent well represents the well depth, the unit of m is Adjacent well represents the compensation adjustment coefficient of the adjacent well, and the standard value is dimensionless.
7. 7. The method of monitoring pressure while drilling for use in different lithologic formations of claim 6, wherein in step S6, the MSE formation pressure of the adjacent well is calculated from the overburden formation pressure, the hydrostatic formation pressure, the MSE trend, and the eaton index correction value of the adjacent well, specifically by the following formula: The MSE stratum pressure of the adjacent well is represented by PP MSE Adjacent well , the unit is g/cm 3 ;MSE Adjacent well , the unit is MPa, the MSEN Adjacent well represents the MSE trend of the adjacent well, the unit is MPa, and the X Adjacent well represents the Eton index correction value of the adjacent well, and the MSE stratum pressure is dimensionless.
8. 8. The method of monitoring pressure while drilling of different lithology strata according to claim 7, wherein in step S7, a dc index stratum pressure weighting coefficient of the adjacent well is calculated according to the dc index stratum pressure of the adjacent well and the measured stratum pressure of the adjacent well, a sigma index stratum pressure weighting coefficient of the adjacent well is calculated according to the sigma index stratum pressure of the adjacent well and the measured stratum pressure of the adjacent well, and a MSE stratum pressure weighting coefficient of the adjacent well is calculated according to the MSE stratum pressure of the adjacent well and the measured stratum pressure of the adjacent well, specifically by the following formula: The method comprises the steps of (a) representing a dc index stratum pressure weighting coefficient of an adjacent well, wherein the dc index stratum pressure weighting coefficient of the adjacent well is dimensionless, b representing a sigma index stratum pressure weighting coefficient of the adjacent well, c representing an MSE stratum pressure weighting coefficient of the adjacent well, wherein the MSE stratum pressure weighting coefficient of the adjacent well is dimensionless, N representing the number of the adjacent wells, which is a positive integer and dimensionless, PP Actual measurement i representing the measured stratum pressure of the adjacent well i, wherein the unit of the measured stratum pressure is g/cm 3 ,i＝1,2,…,N;PP dc Adjacent well i representing the dc index stratum pressure of the adjacent well i, the unit of the measured stratum pressure is g/cm 3 ,i＝1,2,…,N;PP sigma Adjacent well i representing the sigma index stratum pressure of the adjacent well i, the unit of the measured stratum pressure is g/cm 3 ,i＝1,2,…,N;PP MSE Adjacent well i representing the MSE stratum pressure of the adjacent well i, the unit of the measured stratum pressure is g/cm 3 , i=1, 2, and the number of the measured stratum pressures of the adjacent well i.
9. 9. The method for monitoring pressure while drilling for different lithologic formations according to claim 4 or 8, wherein step S8, according to the dc index formation pressure weighting coefficient of the adjacent well, the sigma index formation pressure weighting coefficient of the adjacent well and the MSE formation pressure weighting coefficient of the adjacent well, the dc index formation pressure of the target well, the sigma index formation pressure of the target well and the MSE formation pressure of the target well are weighted and calculated to obtain the formation pressure while drilling of the target well, specifically by the following formula: The method comprises the steps of obtaining a target well, wherein PP represents formation pressure while drilling of the target well, the unit of PP represents g/cm 3 ;PP dc represents dc index formation pressure of the target well, the unit of G/cm 3 ;PP sigma represents sigma index formation pressure of the target well, the unit of G/cm 3 ;PP MSE represents MSE formation pressure of the target well, the unit of g/cm 3 , a represents dc index formation pressure weighting coefficients of adjacent wells, dimensionless, b represents sigma index formation pressure weighting coefficients of the adjacent wells, dimensionless, and c represents MSE formation pressure weighting coefficients of the adjacent wells.
10. 10. The method for pressure while drilling monitoring under a different lithologic formation of any one of claims 1-8, wherein the modification value of the eaton index is greater than 0, less than or equal to 2.

Description

Pressure while drilling monitoring method for stratum with different lithology Technical Field The invention relates to the technical field of petroleum exploration and development, in particular to a pressure while drilling monitoring method for different lithologic strata. Background With the increase of energy demand, the strength of oil and gas resource exploration and development is continuously increased, and exploration targets gradually develop from shallow layers to deep layers, so that the risk of encountering abnormal pressure in the drilling process is increased. As an important basis for guaranteeing the safety of drilling, accurate calculation of formation pore pressure is particularly important. In the drilling operation, proper engineering parameters and drilling fluid density are the precondition guarantee for guaranteeing underground safety and improving drilling efficiency, and accurately mastering the distribution of formation pore pressure is the precondition for carrying out the operation. In recent years, with the continuous deep understanding of formation pressure and continuous refinement of pressure cause analysis, monitoring of formation pressure by rock drillability parameters is realized, however, the use of these methods has a very limited scope, and one monitoring method has higher accuracy for monitoring of formation pressure of a certain lithology and lower accuracy for monitoring of formation pressure of other lithology. However, in the actual drilling process, various lithologies are encountered, and especially for formation lithology complex wells and ultra-deep wells, if the formation pressure of the different lithologies cannot be accurately monitored in real time, the drilling risk is extremely high. Therefore, how to realize a method suitable for monitoring the formation pressure while drilling of different lithologic formations, and the method can achieve higher accuracy for monitoring the formation pressure of different lithologic formations is a problem to be solved by the technicians in the field. Disclosure of Invention In view of the above, the invention provides a method for monitoring the pressure while drilling under different lithologic strata, which is used for carrying out full-coverage monitoring while drilling on the stratum pressure of different lithologic strata, accurately calculating the stratum pressure and reducing the drilling risk and the drilling cost. Therefore, the invention provides a method for monitoring the pressure while drilling in different lithologic formations, which comprises the following steps: S1, collecting the overburden formation pressure, the hydrostatic formation pressure and the drilling fluid density of the area where the target well is located; s2, calculating a dc index, a dc index trend, a sigma index trend, a compensation adjustment coefficient, an MSE trend and an Eton index correction value of the target well; S3, calculating to obtain the dc index formation pressure of the target well according to the overburden formation pressure, the formation hydrostatic pressure, the dc index and the dc index trend of the target well, calculating to obtain the sigma index formation pressure of the target well according to the drilling fluid density, the sigma index trend and the compensation adjustment coefficient of the target well, and calculating to obtain the MSE formation pressure of the target well according to the overburden formation pressure, the formation hydrostatic pressure, the MSE trend and the Eton index correction value of the target well; s4, collecting the overburden formation pressure, the hydrostatic formation pressure and the drilling fluid density of the area where the adjacent well of the target well is located; s5, calculating the dc index, the dc index trend, the sigma index trend, the compensation adjustment coefficient, the MSE trend and the Eton index correction value of the adjacent well; S6, calculating to obtain the dc index formation pressure of the adjacent well according to the overburden formation pressure, the formation hydrostatic pressure, the dc index and the dc index trend of the adjacent well, calculating to obtain the sigma index formation pressure of the adjacent well according to the drilling fluid density, the sigma index trend and the compensation adjustment coefficient of the adjacent well, and calculating to obtain the MSE formation pressure of the adjacent well according to the overburden formation pressure, the formation hydrostatic pressure, the MSE trend and the Eton index correction value of the adjacent well; S7, calculating to obtain a weighting coefficient of the dc index formation pressure of the adjacent well according to the dc index formation pressure of the adjacent well and the measured formation pressure of the adjacent well, calculating to obtain a weighting coefficient of the sigma index formation pressure of the adjacent well according to the sigma index formation