Slurry suspension grouting amount calculation method based on annulus liquid level monitoring

Abstract

The invention relates to the technical field of well leakage prevention and treatment, in particular to a mud hanging and filling amount calculation method based on annulus liquid level monitoring, which comprises the following steps: establishing a relation model of leakage rate and liquid level height in the drilling fluid leakage process, predicting the position of a leakage balance point, and calculating the leakage pressure difference of each measuring point; establishing a relation model of the leakage pressure difference and the leakage rate, and determining a leakage dynamic function; calculating the liquid level height required to be compensated for the drill tool deficit of the lifting drill; calculating a liquid level height required for balancing formation high pressure, and determining a safe liquid level height; and calculating the time from the current liquid level height to the safe liquid level height to obtain the slurry hoisting and filling amount. By means of the liquid level monitoring technology, the reasonable slurry hanging and filling amount is calculated, calculation parameters are easy to obtain, the process is simple and convenient, and important technical guarantee is provided for well control safety and well leakage treatment measure optimization.

Description

Technical Field

[0001] The invention relates to the technical field of well leakage prevention and treatment, and is a method for calculating mud lifting and injection volume based on annular space liquid level monitoring. Background Art

[0002] Under the condition of well leakage, in order to ensure the safety of well control during the drilling operation, the drilling site usually uses the "hanging and grouting" technology to inject a certain amount of mud into the wellbore to maintain the dynamic balance of the well pressure, obtain safe operation time, and prevent leakage and blowout accidents. Determining a reasonable amount of mud lifting and grouting is the key to the "hanging and grouting" operation. If the lifting and grouting amount is insufficient, the pressure of the liquid column in the wellbore cannot balance the high pressure of the formation, which may cause overflow or even blowout accidents; and too much lifting and grouting will cause excessive consumption of drilling fluid and increase drilling costs. At present, the conventional lifting and grouting practice is to grout 1 to 2 cubic meters every 10 minutes in 3 to 5 times when the drill bit is stationary, and to grout 2 to 3 times the volume of the drill bit for each column lifted in the drilling state. This is an empirical estimate. The actual grouting amount needs to be adjusted according to the specific leakage situation, and there is a large uncertainty.

[0003] Liquid level monitoring technology provides a pair of "eyes for observing underground" for mud lifting and grouting operations. It uses the principle of sonar echo detection to measure the position of the wellbore liquid level and accurately determine the change in the liquid level height, so as to determine whether there is overflow in the well and avoid the well control safety risks caused by blind grouting during drilling. However, the existing technology can only provide the liquid level position before and after mud lifting and grouting as a reference for whether the mud lifting and grouting is reasonable or not, without considering the dynamic leakage of drilling fluid during the lifting and grouting process. At the same time, there is a lack of analysis of the leakage-to-spraying factor, and the rationality of the mud lifting and grouting volume has not been effectively solved. Summary of the invention

[0004] The present invention provides a method for calculating the mud lifting and grouting volume based on annular space liquid level monitoring, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problem of quantitative calculation of reasonable grouting volume in existing lifting and grouting operations.

[0005] The technical solution of the present invention is achieved by the following measures: A method for calculating the amount of mud lifting and injection based on annular liquid level monitoring is carried out according to the following steps:

[0006] The first step is to obtain the annular liquid level monitoring data, calculate the drilling fluid loss rate, establish the relationship model between the loss rate and the liquid level during the drilling fluid loss process, predict the position of the loss balance point, and calculate the loss pressure difference at each measuring point;

[0007] The second step is to establish the relationship model between leakage pressure difference and leakage rate and establish the leakage dynamic function;

[0008] The third step is to calculate the liquid level height required to compensate for the drilling tool deficit;

[0009] The fourth step is to calculate the liquid level required to balance the formation high pressure, compare it with the leakage balance position, and determine the safe liquid level according to the liquid level required to compensate for the drilling tool deficit, the liquid level required to balance the formation high pressure and the leakage balance point position;

[0010] The fifth step is to calculate the time from the current liquid level to the safe liquid level, compare it with the required safe operation time, and determine whether lifting and filling is needed;

[0011] The sixth step is to calculate the mud lifting and filling volume by the liquid level height at the beginning of lifting and filling, the liquid level height at the end of lifting and filling and the lifting and filling time when lifting and filling are needed.

[0012] The following are further optimizations and / or improvements to the above technical solutions:

[0013] In the first step above, the annular liquid level monitoring data is the wellbore annular liquid level height measured in real time by the liquid level monitor under well leakage return conditions. The number of measuring points is 10 to 25, and the measuring points cover high, medium and low leakage rate areas.

[0014] In the first step above, according to the relationship model between the leakage rate and the liquid level during the drilling fluid leakage process, when the drilling fluid leakage rate is zero, the leakage balance point position H0 is calculated.

[0015] In the first step above, the drilling fluid loss rate is obtained by multiplying the change in liquid level per unit time by the cross-sectional area of ​​the annulus. The calculation formula is:

[0016]

[0017] Where Q is the drilling fluid loss rate, m 3 / h; D is the inner diameter of the wellbore, m; d is the outer diameter of the drill string, m; ΔH is the change in the liquid level between two adjacent measuring points, m; Δt is the time difference between two adjacent measuring points, h.

[0018] In the first step above, the leakage pressure difference at each measuring point is calculated using the liquid level difference between the measuring point and the leakage balance point. The calculation formula is:

[0019] ΔP=ρg(H0-H) Formula 2

[0020] Where ΔP is the leakage pressure difference, MPa; ρ is the drilling fluid density, g / cm 3 ; H is the liquid level height at the measuring point, m; H0 is the liquid level height at the leakage equilibrium point, m; g is the gravitational acceleration.

[0021] In the second step above, the relationship between the leakage pressure difference and the leakage rate is characterized by the leakage dynamic function, and the fitting function expression of the leakage dynamic function is:

[0022] Q=A+B*exp(C*ΔP) Formula 3

[0023] Where Q is the drilling fluid loss rate, m 3 / h; ΔP is the leakage pressure difference, MPa; A, B, C are correlation coefficients.

[0024] In the third step above, the calculation formula for the liquid level required to compensate for the drilling tool deficit is:

[0025]

[0026] In the formula, H c is the height of the drilling tool deficit compensation liquid level, m; S is the cross-sectional area of ​​the drill pipe, m 2 ; r is the inner diameter of the drill pipe, m; L is the drill lifting length, m.

[0027] In the fourth step above, the calculation formula for the liquid level required to balance the formation high pressure, that is, the liquid level required to balance the highest pressure point in the open hole section (adding a safety pressure coefficient for well control safety) is:

[0028]

[0029] In the formula, H p Liquid level required to balance formation high pressure, m; H v is the vertical depth of the high-pressure point of the formation, m; k is the formation pressure coefficient, dimensionless; α is the additional safety factor, dimensionless, with values ​​ranging from 0.05 to 0.1 for oil wells and 0.07 to 0.15 for gas wells.

[0030] In the fourth step above, the safe liquid level height H s The value conditions are:

[0031]

[0032] In the fifth step above, based on the fact that the mud loss is equal to the amount of mud reduction in the wellbore annulus, the calculation formula for the time it takes for the wellbore liquid level to leak from the current liquid level to the safe liquid level is:

[0033]

[0034] Where, T L H is the time from the current liquid level leakage to the safe liquid level height, h; m is the current measured liquid level, m; H s is the safe liquid level height, m; ρ is the drilling fluid density, g / cm 3 ; A, B, C are correlation coefficients;

[0035] If T L If it is less than the required safe working time, lifting and pouring is required, otherwise it is not required.

[0036] In the sixth step above, the calculation expression of mud lifting and injection volume is:

[0037]

[0038] Where, T m T is the time from the start of lifting filling to the current liquid level measurement point, h; s is the safe operation time, h; T0 is the lifting time, h; H1 is the liquid level at the beginning of lifting, m; H2 is the liquid level at the end of lifting, m; H m is the current measured liquid level, m; H s is the safe liquid level height, m; q is the suspension filling flow, m 3 / h; V is the mud lifting and filling volume, m 3 .

[0039] The present invention solves the empirical grouting problem existing in the existing "hanging grouting" technology. With the help of liquid level monitoring technology, a dynamic analysis model of wellbore leakage is established to calculate a reasonable mud hanging grouting volume. The calculation parameters required by this method are easy to obtain and the calculation process is simple, which provides important technical guarantee for the optimization of well control safety and well leakage treatment measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Attached Figure 1 This is a curve diagram of the leakage dynamic function model in Example 12 of the present invention. DETAILED DESCRIPTION

[0041] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0042] The present invention will be further described below in conjunction with embodiments:

[0043] Example 1: The method for calculating the amount of mud lifting and injection based on annular liquid level monitoring is carried out according to the following steps:

[0044] The first step is to obtain the annular liquid level monitoring data, calculate the drilling fluid loss rate, establish the relationship model between the loss rate and the liquid level during the drilling fluid loss process, predict the position of the loss balance point, and calculate the loss pressure difference at each measuring point;

[0045] The second step is to establish the relationship model between leakage pressure difference and leakage rate and establish the leakage dynamic function;

[0046] The third step is to calculate the liquid level height required to compensate for the drilling tool deficit;

[0047] The fourth step is to calculate the liquid level required to balance the formation high pressure, compare it with the leakage balance position, and determine the safe liquid level according to the liquid level required to compensate for the drilling tool deficit, the liquid level required to balance the formation high pressure and the leakage balance point position;

[0048] The fifth step is to calculate the time from the current liquid level to the safe liquid level, compare it with the required safe operation time, and determine whether lifting and filling is needed;

[0049] The sixth step is to calculate the mud lifting and filling volume by the liquid level height at the beginning of lifting and filling, the liquid level height at the end of lifting and filling and the lifting and filling time when lifting and filling are needed.

[0050] Embodiment 2: As an optimization of the above embodiment, in the first step, the annular liquid level monitoring data is the wellbore annular liquid level height measured in real time by the liquid level monitor under the condition of well leakage return, and the number of measuring points is 10 to 25, and the measuring points cover high, medium and low leakage rate areas. In the present invention, the number of measuring points needs to be more than 10, and multiple measuring points and comprehensive leakage point coverage can improve the model fitting accuracy.

[0051] Embodiment 3: As an optimization of the above embodiment, in the first step, according to the relationship model between the leakage rate and the liquid level during the leakage of drilling fluid, when the leakage rate of drilling fluid is zero, the leakage balance point position H0 is calculated.

[0052] Embodiment 4: As an optimization of the above embodiment, in the first step, the drilling fluid loss rate is obtained by multiplying the change in liquid level per unit time by the cross-sectional area of ​​the annulus, and the calculation formula is:

[0053]

[0054] Where Q is the drilling fluid loss rate, m 3 / h; D is the inner diameter of the wellbore, m; d is the outer diameter of the drill string, m; ΔH is the change in the liquid level between two adjacent measuring points, m; Δt is the time difference between two adjacent measuring points, h.

[0055] Embodiment 5: As an optimization of the above embodiment, in the first step, the leakage pressure difference of each measuring point is calculated by using the liquid level difference between the measuring point and the leakage balance point, and the calculation formula is:

[0056] ΔP=ρg(H0-H) Formula 2

[0057] Where ΔP is the leakage pressure difference, MPa; ρ is the drilling fluid density, g / cm 3 ; H is the liquid level height at the measuring point, m; H0 is the liquid level height at the leakage equilibrium point, m; g is the gravitational acceleration.

[0058] Embodiment 6: As an optimization of the above embodiment, in the second step, the relationship between the leakage pressure difference and the leakage rate is characterized by a leakage dynamic function, and the fitting function expression of the leakage dynamic function is:

[0059] Q=A+B*exp(C*ΔP) Formula 3

[0060] Where Q is the drilling fluid loss rate, m 3 / h; ΔP is the leakage pressure difference, MPa; A, B, C are correlation coefficients.

[0061] Embodiment 7: As an optimization of the above embodiment, in the third step, the liquid level height required to compensate for the drilling tool deficit is calculated as follows:

[0062]

[0063] In the formula, H c is the height of the drilling tool deficit compensation liquid level, m; S is the cross-sectional area of ​​the drill pipe, m 2 ; r is the inner diameter of the drill pipe, m; L is the length of the drill lifting, m. The influence of the volume change of the drill pipe joint is ignored in the calculation process of the liquid level height required to compensate for the deficit of the drill tool during the drill lifting.

[0064] Embodiment 8: As an optimization of the above embodiment, in the fourth step, the liquid level required to balance the formation high pressure, that is, the liquid level required to balance the highest pressure point of the open hole section (adding a safety pressure coefficient for well control safety) is calculated as follows:

[0065]

[0066] In the formula, H p Liquid level required to balance formation high pressure, m; H v is the vertical depth of the high-pressure point of the formation, m; k is the formation pressure coefficient, dimensionless; α is the additional safety factor, dimensionless, with values ​​ranging from 0.05 to 0.1 for oil wells and 0.07 to 0.15 for gas wells.

[0067] Embodiment 9: As an optimization of the above embodiment, in the fourth step, the safety liquid level height H s The value conditions are:

[0068]

[0069] Embodiment 10: As an optimization of the above embodiment, in the fifth step, according to the mud loss being equal to the mud reduction in the wellbore annulus, the calculation formula for the time it takes for the wellbore liquid level to leak from the current liquid level to the safe liquid level is:

[0070]

[0071] Where, T L H is the time from the current liquid level leakage to the safe liquid level height, h; m is the current measured liquid level, m; H s is the safe liquid level height, m; ρ is the drilling fluid density, g / cm 3 ; A, B, C are correlation coefficients.

[0072] If T LIf it is less than the required safe working time, lifting and pouring is required, otherwise it is not required.

[0073] Embodiment 11: As an optimization of the above embodiment, in the sixth step, the calculation expression of the mud lifting and pouring amount is:

[0074]

[0075] Transforming the above formula, we can get:

[0076]

[0077] Where, T m T is the time from the start of lifting filling to the current liquid level measurement point, h; s is the safe operation time, h; T0 is the lifting time, h; H1 is the liquid level at the beginning of lifting, m; H2 is the liquid level at the end of lifting, m; H m is the current measured liquid level, m; H s is the safe liquid level height, m; q is the suspension filling flow, m 3 / h; V is the mud lifting and filling volume, m 3 .

[0078] Example 12: Application of the mud lifting and injection volume calculation method based on annular liquid level monitoring in the MH1 well in the Mahu X well area includes the following steps:

[0079] The first step is to use the liquid level monitor to obtain the liquid level monitoring data of the MH1 well leakage. Since the outer diameter D of the casing is 244.48 mm, the wall thickness is 11.05 mm, and the outer diameter d of the drill pipe is 127 mm, the cross-sectional area of ​​the annulus can be calculated to be 0.0262 m 2 The drilling fluid loss rate is calculated by the change of the liquid level at adjacent measuring points, and the relationship model between the loss rate and the liquid level during the drilling fluid loss process is established by using the curve fitting method:

[0080] Q=-2.86+23.85e -0.003H , correlation coefficient R 2 =0.99.

[0081] When the drilling fluid loss rate is zero, the liquid level is calculated to be 706.99m, which is the position of the loss balance point. The calculation formula for the loss pressure difference is: ΔP = 1.54 × 0.00981 × (706.99-H) = 10.68-0.015H. The calculation results of each measuring point are shown in Table 1.

[0082] The second step is to establish a leakage dynamic function model that characterizes the relationship between leakage rate and leakage pressure difference by using curve fitting method (see Figure 1 )for:

[0083] Q=-2.9+2.25e0.221ΔP , correlation coefficient R 2 =0.99.

[0084] In the third step, it is planned to raise the drill by 3 columns, with a lifting length of 27.16m. Therefore, the drilling tool deficit compensation liquid level height is:

[0085]

[0086] Step 4: The formation pressure coefficient k of the abnormally high pressure oil layer at 4595.32 m in the same open hole section is 1.34, and the additional safety pressure coefficient α is 0.05. Therefore, the liquid level required to balance the formation high pressure is:

[0087]

[0088] Since the leakage balance liquid level is greater than the liquid level required to balance the high pressure, the safe liquid level is:

[0089] H s =447.60-3.63=443.97m.

[0090] Step 5: Current wellbore liquid level H m The liquid level is 411.6m, and the time it takes to reach the safe liquid level is:

[0091]

[0092] Since the safe working time required for this drilling operation is 0.42h, which is longer than the time it takes for the current liquid level to leak to the safe liquid level height, lifting and filling are required.

[0093] Step 6: Start grouting with original density after 0.23h from the liquid level of 411.6m. First, calculate the liquid level height at the beginning of hanging grouting:

[0094]

[0095] Calculation shows that H1=436.87m.

[0096] Then calculate the liquid level at the end of the lifting and filling (the safe operation time is 0.42h):

[0097]

[0098] Calculation shows that H2=396.84m.

[0099] Then calculate the lifting and filling time (the lifting and filling flow is calculated at 20L / s):

[0100]

[0101] Finally, the mud lifting and injection volume is calculated:

[0102]

[0103] The present invention provides a technical solution for quantitatively calculating the mud lifting and injection volume, deeply explores the value of annular space liquid level monitoring data, establishes a leakage dynamic function model, comprehensively considers the influencing factors such as drilling tool deficit and formation high pressure, constructs a mud lifting and injection volume calculation model, realizes the quantitative calculation of the reasonable mud lifting and injection volume, and provides a modeling, quantitative and scientific evaluation method for the prevention and treatment of lost return well leakage.

[0104] To sum up, the mud lifting and injection volume calculation method based on annulus liquid level monitoring of the present invention, with the help of annulus liquid level monitoring technology, provides a scientific and effective quantitative evaluation means for the calculation of mud lifting and injection volume under well leakage and return conditions, ensures the rationality of the lifting and injection mud, reduces the drilling fluid cost, ensures the safety of well control, provides technical support for well leakage treatment and prevention, is conducive to the promotion and application of well leakage on site, and has a good application scenario.

[0105] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

[0106] Table 1

[0107]

Claims

1. A method for calculating the amount of mud lifting and injection based on annular liquid level monitoring, characterized in that Follow these steps: The first step is to obtain the annular liquid level monitoring data, calculate the drilling fluid loss rate, establish the relationship model between the loss rate and the liquid level during the drilling fluid loss process, predict the position of the loss balance point, and calculate the loss pressure difference at each measuring point; The second step is to establish the relationship model between leakage pressure difference and leakage rate and establish the leakage dynamic function; The third step is to calculate the liquid level height required to compensate for the drilling tool deficit; The fourth step is to calculate the liquid level required to balance the formation high pressure, compare it with the leakage balance position, and determine the safe liquid level according to the liquid level required to compensate for the drilling tool deficit, the liquid level required to balance the formation high pressure and the leakage balance point position; The fifth step is to calculate the time from the current liquid level to the safe liquid level, compare it with the required safe operation time, and determine whether lifting and filling is needed; The sixth step is to calculate the mud lifting and filling volume by the liquid level height at the beginning of lifting and filling, the liquid level height at the end of lifting and filling and the lifting and filling time when lifting and filling are needed.

2. The method for calculating the amount of mud lifting and injection based on annular liquid level monitoring according to claim 1 is characterized in that In the first step, the annular liquid level monitoring data is the wellbore annular liquid level height measured in real time by the liquid level monitor under the well leakage return condition, the number of measuring points is 10 to 25, and the measuring points cover high, medium and low leakage rate areas; or / and, in the first step, according to the relationship model between the leakage rate and the liquid level height during the drilling fluid leakage process, when the drilling fluid leakage rate is zero, the leakage balance point position H0 is calculated.

3. The method for calculating the amount of mud lifting and injection based on annular liquid level monitoring according to claim 1 or 2, characterized in that In the first step, the drilling fluid loss rate is obtained by multiplying the change in liquid level per unit time by the cross-sectional area of ​​the annulus. The calculation formula is: Where Q is the drilling fluid loss rate, m 3 / h; D is the inner diameter of the wellbore, m; d is the outer diameter of the drill string, m; ΔH is the change in the liquid level between two adjacent measuring points, m; Δt is the time difference between two adjacent measuring points, h.

4. The method for calculating the amount of mud lifting and injection based on annular space liquid level monitoring according to any one of claims 1 to 3, characterized in that In the first step, the leakage pressure difference of each measuring point is calculated by using the liquid level difference between the measuring point and the leakage balance point. The calculation formula is: ΔP=ρg(H0-H) Formula 2 Where ΔP is the leakage pressure difference, MPa; ρ is the drilling fluid density, g / cm 3 ; H is the liquid level height at the measuring point, m; H0 is the liquid level height at the leakage equilibrium point, m; g is the gravitational acceleration.

5. The method for calculating the amount of mud lifting and injection based on annular space liquid level monitoring according to any one of claims 1 to 4, characterized in that In the second step, the relationship between the leakage pressure difference and the leakage rate is characterized by the leakage dynamic function. The fitting function expression of the leakage dynamic function is: Q=A+B*exp(C*ΔP) Formula 3 Where Q is the drilling fluid loss rate, m 3 / h; ΔP is the leakage pressure difference, MPa; A, B, C are correlation coefficients.

6. The method for calculating the amount of mud lifting and injection based on annular liquid level monitoring according to any one of claims 1 to 5, characterized in that In the third step, the liquid level required to compensate for the drilling tool deficit is calculated as follows: In the formula, H c is the height of the drilling tool deficit compensation liquid level, m; S is the cross-sectional area of ​​the drill pipe, m 2 ; r is the inner diameter of the drill pipe, m; L is the drill lifting length, m.

7. The method for calculating the amount of mud lifting and injection based on annular space liquid level monitoring according to any one of claims 1 to 6, characterized in that In the fourth step, the calculation formula for the liquid level required to balance the formation high pressure is: In the formula, H p Liquid level required to balance formation high pressure, m; H v is the vertical depth of the high-pressure point of the formation, m; k is the formation pressure coefficient, dimensionless; α is the additional safety factor, dimensionless, with values ​​ranging from 0.05 to 0.1 for oil wells and 0.07 to 0.15 for gas wells.

8. The method for calculating the amount of mud lifting and injection based on annular space liquid level monitoring according to any one of claims 1 to 7, characterized in that In the fourth step, the safe liquid level height H s The value conditions are:

9. The method for calculating the amount of mud lifting and injection based on annular space liquid level monitoring according to any one of claims 1 to 8, characterized in that In the fifth step, according to the fact that the mud loss is equal to the amount of mud reduction in the wellbore annulus, the calculation formula for the time it takes for the wellbore liquid level to leak from the current liquid level to the safe liquid level is: Where, T L H is the time it takes for the current liquid level to leak to the safe liquid level, h; m is the current measured liquid level, m; H s is the safe liquid level height, m; ρ is the drilling fluid density, g / cm 3 ; A, B, C are correlation coefficients; If T L If it is less than the required safe working time, lifting and pouring is required, otherwise it is not required.

10. The method for calculating the amount of mud lifting and injection based on annular liquid level monitoring according to any one of claims 1 to 9, characterized in that In the sixth step, the calculation expression of mud lifting and filling volume is: Where, T m T is the time from the start of lifting filling to the current liquid level measurement point, h; s is the safe operation time, h; T0 is the lifting time, h; H1 is the liquid level at the beginning of lifting, m; H2 is the liquid level at the end of lifting, m; H m is the current measured liquid level, m; H s is the safe liquid level height, m; q is the suspension filling flow, m 3 / h; V is the mud lifting and filling volume, m 3 .

Images