Method for evaluating safety drilling probability of ultra-high temperature and high pressure development based on Weibull function

An ultra-high temperature and functional technology, applied in the field of oil drilling and production, can solve the problems of not using actual measured value samples and probability statistical analysis, etc., and achieve the effect of clear and feasible technical route, avoiding high-risk operations, and wide data sources

Pending Publication Date: 2021-02-09
CHINA NATIONAL OFFSHORE OIL (CHINA) CO LTD +1
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Problems solved by technology

In terms of the probability assessment of safe drilling, the existing methods deal with the uncertainty of pore pressure and fracture pressure according to "assuming a normal distribution", which is only a qualitative assumption and does not use measured value samples and probability statistics analysis

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  • Method for evaluating safety drilling probability of ultra-high temperature and high pressure development based on Weibull function
  • Method for evaluating safety drilling probability of ultra-high temperature and high pressure development based on Weibull function
  • Method for evaluating safety drilling probability of ultra-high temperature and high pressure development based on Weibull function

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Embodiment Construction

[0041] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0042] The materials and reagents used in the following examples can be obtained from commercial sources unless otherwise specified.

[0043] The flow chart of the method for evaluating the safe drilling probability of ultra-high temperature and high pressure development based on Weibull function provided by the present invention is as follows figure 1 shown, including the following steps:

[0044] 1) Obtain pore pressure data samples of ultra-high temperature and high pressure formations according to the results of pressure measurement sampling (MDT) and drill pipe formation testing (DST) of ultra-high temperature and high pressure exploration wells;

[0045] 2) According to the ground leakage experimental data of ultra-high temperature and high pressure exploration wells and the calculated value of bottom hole pressure when leakage occurs during drilling, a ...

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Abstract

The invention discloses a method for evaluating the safety drilling probability of ultra-high temperature and high pressure development based on a Weibull function. The method comprises the followingsteps: collecting a pore pressure data sample of an ultrahigh-temperature high-pressure stratum and a vertical well fracture pressure data sample; obtaining probability density distribution of the pore pressure of each section and the fracture pressure of a vertical well according to the occurrence frequency of the pore pressure of each section and the fracture pressure of the vertical well; determining a dual-parameter Weibull function expression of pore pressure and vertical well fracture pressure probability density; integrating to obtain a cumulative probability function expression of thepore pressure and the vertical well fracture pressure; determining a cumulative probability expression of the vertical well safety pressure; determining a cumulative probability expression of the safety pressure of a directional well; and calculating a safe drilling probability value of the ultrahigh-temperature and high-pressure directional well. By means of the method, the safe drilling probability can be evaluated before drilling of a development well, high-risk operation is avoided, cost and safety accidents are reduced, and the method has important significance in development of an ultra-high-temperature and high-pressure oil and gas field.

Description

technical field [0001] The invention relates to a Weibull function-based method for evaluating the safe drilling probability of ultra-high temperature and high pressure development, belonging to the field of petroleum drilling. Background technique [0002] In ultra-high temperature and high pressure oil and gas fields, the deep formation temperature exceeds 180°C, the pore pressure coefficient exceeds 2.20, and the fracture pressure coefficient of vertical wells is generally lower than 2.42. The pressure window is narrow, the accident rate is high, and drilling risks are extremely high. In order to ensure the safe and economical development of ultra-high temperature and high pressure oil and gas fields, it is necessary to quantitatively evaluate the safe drilling probability value of development wells (directional wells) in the pre-drilling stage based on the statistical analysis of drilled wells. [0003] Compared with normal temperature and pressure and general high tempe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/18G06Q10/06G06Q50/02
CPCG06F17/18G06Q10/0635G06Q10/0639G06Q50/02
Inventor 李中袁俊亮谢仁军范白涛幸雪松吴怡徐国贤周长所贾宗文付兴
Owner CHINA NATIONAL OFFSHORE OIL (CHINA) CO LTD
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