一、主要进展

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反渔朱
5 years ago
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1 Research Prospect of Risk Assessment Technology of Exploration Drilling in High Sulfur Gas Field DONG Yao FAN Jian-chun

Problems of Exploration Drilling in High-sulfur Gas Field 1.high and steep structure prevails 2.hard lithology, strong abrasiveness and bad drillability 3.easy to collapse 4.

2 Problems of Exploration Drilling in High-sulfur Gas Field 1.high and steep structure prevails 2.hard lithology, strong abrasiveness and bad drillability 3.easy to collapse 4. narrow safety window and severe loss circulation Formation dip Sand-shale + thin-shale Easy to collapse Fault, crack, cava development 5.Several pressure systems coexist 6.bad well conditions 7.long open hole, small clearance, much leakage, difficult to cement extremely high risk 油气安全工程技术研究中心

3 Features of Exploration Drilling in High-sulfur Gas Field time-varying uncertain strata structure shaft integrity condition well structure formation fluid formation pressure strata structure High measure adjusting frequency Drilling system of high sulfur gas wells is a strong time-varying and uncertain system

4 Research Status Because normal risk assessment methods are only suitable for steady state systems, it is of great difficulty to real-timely master the safety status of the drilling system to further guide drilling operation. The main technical contents of risk assessment method aiming at offshore drilling platform in China are as follows:

1 Using preliminary hazard analysis (PHA) to

various accidents, using emergency model to analyze the

accident conditions 油气安全工程技术研究中心 3 Analyzing the safety

5 1 Using preliminary hazard analysis (PHA) to systematically identify various risk sources in the drilling operations. 2 Simulating and calculating the influence scopes of various accidents, using emergency model to analyze the key points of risk of operating personnel under various accident conditions 油气安全工程技术研究中心 3 Analyzing the safety control mode of drilling operation and bringing forward corresponding measures and suggestions according to the key points of risk

6 Geological data Drilling data Logging data Data correction Schlumberger dynamic risk Fault top Elastic coefficient Drillable profile Pore profile management of drilling pressure Stress profile Stress direction Stratum model Operation analysis and forecast Drilling Risk Profile Risk forecast & countermeasu re of drilling Drilling and geological liability scheme Yes Plan matche s reality Data check & analysis Risk countermeas ures in the next day Task and liability in 24hr No Accident report Rede sign Damage Reality reflection Liability report No damage Recent impleme ntation report General rig & Geological condition Drilling Team

7 Risk Assessment Method of Drilling Process Index to be assessed of drilling parameters Drilling parameter Drilling fluid density Hydraulic parameter Lifting velocity Hydraulic horsepower Bit hydraulic horsepower Jet velocity Impact force Annular pressure drop Bit pressure drop Standpipe pressure displacement speed Bit pressure 油气安全工程技术研究中心

8 Selection of risk assessment method Because the drilling parameter system has the features of multiple purposes, multiple index and the coexistence of certainty and uncertainty, the set pair analysis theory can be applied to the risk assessment of drilling parameter system.

9 Brief Introduction of the Set Pair Analysis Theory The formula of the set pair analysis theory μ=a+bi+cj a, b and c respectively represents the identical degree, the neutral degree and the opposite degree. i and j are respectively the mark symbol or corresponding coefficient of the neutral degree and the opposite degree.

10 Determination of quantitative index Risk grading standard Actual data Set pair Delphi method Calculation of connection degree of each of the index to each of the risk grades Determination of the weight of the index Calculation of the total connection degree Determination of the risk grade Set Pair Analysis Countermeasure

11 Mathematical model (1) If the smaller the index value S is, the safer the system is, when the risk assessment index is in the 1st grade (I) μi1= 1 x [0, Si(1)] 1+ x [Si(1),S i(2)] -1 x [Si(2), + ]

12 Mathematical model (2) When the risk assessment index is in the 2nd grade (II) μi2= 1 x [Si(1),S i(2)] 1+ x [Si(2),S i(3)] -1 x [Si(3), + ] 1 x [0, Si(1)]

13 Mathematical model (3)When the risk assessment index is in the 3rd grade (III) μi3= 1 x [Si(2),S i(3)] 1+ x [Si(3),S i(4)] 1+ x [Si(1),S i(2)] -1 x [-,S i(1)] or x [Si(4), + ]

14 Mathematical model (4)When the risk assessment index is in the 4th grade (IV) μi4= 1 x [Si(2),S i(3)] 1+ x [Si(3),S i(4)] 1+ x [Si(1),S i(2)] -1 x [-,S i(1)] or x [Si(4), + ]

15 Mathematical model (5) When the risk assessment index is in the 5th grade (V) μi5= 1 x [Si(4),S i(5)] 1+ x [Si(3),S i(4)] -1 x [-,S i(3)]

16 Nature The nature of the risk assessment of the drilling parameter system based on the set pair analysis theory is making the realtime monitoring data and the risk grading standard of each of the index compose a set pair, then the risk grade of the drilling parameter system can be obtained.

17 Index Optimization The deviation value of the index monitoring value from the index optimal value which is suitable for formation pressure system can be regarded as the assessment index for the mathematical model.

18 Application Example Supposing that the drilling fluid density in the first spud in section of a certain well is 1.14~1.16g/cm3, while the optimum drilling fluid density for this well section is g/cm3, the speed in this section is 61~69r/min, while the optimum speed for this well section is 63 r/min.

19 And supposing the risk grading standard and the weight of the drilling fluid density and the speed for this first spun in section of this well are as follows: under the condition of only considering the drilling fluid density and the speed, the results are as follows:

20 Risk Grading Standard for Deviation Value of Drilling Parameter System Index Risk grade Deviation value of drilling fluid density (g/cm3) Deviation value of speed (r/min) I safe II relatively safe III generally safe IV unsafe V extremely unsafe

21 Monitoring Value of Drilling Parameter System Index Index Deviation value of the minimal design value of drilling fluid density (g/cm3) Deviation value of the maximum design value of drilling fluid density (g/cm3) Deviation limit of speed (r/min) value

22 Weight of Risk Assessment Index of Drilling Parameter System Index Deviation limit of drilling fluid density Deviation limit of speed value

23 General Connection Degree of Every Risk Grade of the Phenomena that the Formation is fractured Connection degree I I I I I I I V V μj The risk grade of the phenomena that the formation is fractured during the drilling process in this section is grade I. 油气安全工程技术研究中心

24 General Connection Degree of Every Risk Grade of the Phenomena that the Formation Fluid Invades the Shaft Connection degree I I I I I I I V V μj The risk grade of the phenomena that the formation is fractured during the drilling process in this section is grade II.

25 Difficulty The emphasis and the difficulty of assuring the correctness of the risk assessment result is assuring the scientific and the accuracy of the index weight and the risk grading standard of every index.

26 Conclusion The set pair analysis method can be applied to the risk assessment of drilling process. The assessment result can provide preference for real-timely guiding drilling process.

27 The set pair analysis method is an effectively way to analyze uncertain multiple-objective decision making problems.

28 The end Thank you!

Thesis for the Master degree in Engineering Research on Negative Pressure Wave Simulation and Signal Processing of Fluid-Conveying Pipeline Leak Candi

U17 10220 UDC624 Thesis for the Master degree in Engineering Research on Negative Pressure Wave Simulation and Signal Processing of Fluid-Conveying Pipeline Leak Candidate:Chen Hao Tutor: Xue Jinghong