CN110872948B - System for actively detecting lost circulation by utilizing radioactive indicator - Google Patents
System for actively detecting lost circulation by utilizing radioactive indicator Download PDFInfo
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- CN110872948B CN110872948B CN201911403339.5A CN201911403339A CN110872948B CN 110872948 B CN110872948 B CN 110872948B CN 201911403339 A CN201911403339 A CN 201911403339A CN 110872948 B CN110872948 B CN 110872948B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/01—Devices for supporting measuring instruments on drill bits, pipes, rods or wirelines; Protecting measuring instruments in boreholes against heat, shock, pressure or the like
Abstract
The invention provides a system for actively detecting lost circulation by utilizing radioactive indicators, which comprises a detector and a calculation and judgment unit, wherein the detector is arranged on a drilling tool close to a drill bit, the detector comprises a far-end probe and a near-end probe which are sequentially arranged along a drilling direction, and the near-end probe and the far-end probe can sequentially pass through the depth of a well to be detected at different moments and detect the gamma value of the radioactive indicators at the depth of the well to be detected when the radioactive indicators pass through the depth of the well to be detected; the calculation and judgment unit comprises a first calculation and judgment subunit and a second calculation and judgment subunit which are connected with each other, the first calculation and judgment subunit can judge whether the stratum to be detected has lost circulation, and the second calculation and judgment subunit receives the judgment result of the first calculation and judgment subunit and calculates the drilling fluid loss while drilling position of the stratum with lost circulation. The system can realize the active detection of the position and the leakage strength of the lost circulation, and has high lost circulation finding speed and short delay time.
Description
Technical Field
The invention relates to the technical field of oil and gas exploration, in particular to a system for actively detecting lost circulation by using radioactive indicators.
Background
The phenomenon that drilling fluid is lost into a stratum or other interlayers through an exposed stratum or a damaged casing which is lost in the drilling and completion process is called drilling fluid loss, namely lost circulation.
The problems of borehole instability, collapse due to leakage and blowout caused by the leakage are the main technical bottlenecks which restrict the oil-gas exploration and development speed for a long time, and the occurrence of the leakage not only brings loss to the drilling engineering, but also brings great difficulty to the exploration and development of oil-gas resources. If the leakage is not found in time or the depth of the leakage is not clear, the well kick or blowout is often caused, so that the life and property loss is caused, the drilling construction period is greatly influenced, and the drilling cost is increased. Lost circulation is of great importance for quality and safety control of the drilling process. How to quickly and accurately find the lost circulation has become a focus of industrial attention. However, due to the lack of sophisticated and reliable identification techniques, the discovery and detection of lost circulation has been considered as one of the worldwide problems in drilling engineering.
The traditional well fluid leakage position determining device does not have the capability of accurately and timely positioning the well leakage position, and the difficulty is increased for leaking stoppage. If the position of the lost circulation needs to be determined, a spiral flowmeter, a well temperature measuring device, a resistivity measuring device and the like are adopted, and the devices generally lack timeliness, so that the construction period can be greatly prolonged, and the drilling cost is increased.
Disclosure of Invention
In view of the deficiencies in the prior art, it is an object of the present invention to address one or more of the problems in the prior art as set forth above. For example, one of the objectives of the present invention is to provide a system for actively detecting lost circulation, which can accurately determine the position of lost circulation and find the lost circulation at a high speed.
The invention provides a system for actively detecting lost circulation by utilizing radioactive indicators, which can comprise a detector and a calculation and determination unit, wherein the detector is arranged on a drilling tool close to a drill bit, the detector comprises a far-end probe and a near-end probe which are sequentially arranged along the drilling direction, and the near-end probe and the far-end probe can sequentially pass through the same well depth at different times and detect the gamma value of the radioactive indicators at the well depth; the calculation and determination unit comprises a first calculation and determination subunit and a second calculation and determination subunit which are connected with each other, the first calculation and determination subunit respectively receives detection values obtained by the near-end probe and the far-end probe and determines whether the well depth has the well leakage according to the change conditions of the detection value of the near-end probe and the detection value of the far-end probe, and the second calculation and determination subunit receives the determination result of the first calculation and determination subunit and calculates the drilling fluid leakage while drilling position.
In one exemplary embodiment of the system of the present invention for actively detecting lost circulation using a radioactive indicator, the radioactive indicator has a coefficient of variation from the formation of greater than 0.2, wherein,
wherein D is g Representing the coefficient of difference, G, of the radioactive indicator from the formation t Represents the natural radioactivity of the radioactive indicator; g d Representing the average of the natural radioactivity of the formation.
Compared with the prior art, the system has the beneficial effects that:
(1) The system can realize the active detection of the position and the leakage strength of the lost circulation, and has high lost circulation finding speed and short delay time;
(2) The system can adjust and replace the type and concentration of the radioactive indicator according to different stratum properties, the detection is accurate and flexible, and the position of the lost circulation is judged directly;
(3) The system can judge the well leakage of the positive drilling layer and the re-leakage of the leaking layer and can determine whether the re-leakage occurs.
Drawings
The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 shows a system schematic of one exemplary embodiment of a system for actively detecting lost circulation using a radioactive indicator of the present invention.
Detailed Description
Hereinafter, a system for actively detecting lost circulation using radioactive indicators according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.
FIG. 1 shows a system schematic of one exemplary embodiment of a system for actively detecting lost circulation with a radioactive indicator of the present invention.
The invention provides a system for actively detecting lost circulation by radioactive indicators, which is particularly suitable for judging the loss condition of drilling fluid while drilling. In one exemplary embodiment of the radioactive indicator active leak detection system of the present invention, as shown in FIG. 1, the system may include a detector and a computational decision unit. Wherein, the first and the second end of the pipe are connected with each other,
the sonde may be located in the drill section near the drill bit. The vertical distance between the detector and the drill bit can be determined according to the actual drilling site condition on site, and can be set in cooperation with the formation property and the drilling speed. The detector is arranged at a position close to the drill bit, so that the lost circulation condition can be judged more quickly, and the judged result can be more accurate. The detector may comprise a distal probe and a proximal probe arranged in sequence along the drilling direction, i.e. a certain distance is provided between the proximal probe and the distal probe. The set distance is related to the background radiation value, the drilling radiation value and the drilling rate of the stratum rock and can be set according to the actual situation on site. The proximal probe is positioned closer to the drill bit than the distal probe. For a certain well depth to be measured, the detector can move along with the drilling process in the drilling process, and the near-end probe is closer to the drill bit, so that the near-end probe can reach the well depth to be measured firstly and contact the radioactive indicator at the deep well to be measured firstly, and the gamma value of the radioactive indicator at the deep well to be measured is effectively detected at the moment. Along with the drilling, the far-end probe reaches the well depth to be detected and effectively detects the gamma value of the radioactive indicator at the well depth to be detected. If the leakage exists, the stratum and the drilling fluid can be subjected to fluid exchange, the concentration of the radioactive indicator in the drilling fluid is influenced, whether the leakage exists at the well depth can be judged according to the change condition between the gamma detection value of the near-end probe and the gamma detection value of the far-end probe, and the condition whether the leakage exists in the stratum to be detected can be determined.
The calculation and decision unit may be connected to the detector. The calculation determination unit may include a first calculation determination subunit and a second calculation determination subunit connected to each other. The first calculation judging subunit can judge whether the formation to be detected has lost circulation or not. The second calculation determination subunit is capable of determining the location of the lost circulation for the formation in which the lost circulation is present. In the stratum to be detected, a plurality of well depths in the stratum can be detected to judge whether the well leakage exists. The first calculation judgment subunit can respectively receive gamma detection values obtained by the near-end probe and the far-end probe, and judges whether the stratum to be detected has lost circulation or not according to the near-end probe detection value, the far-end probe detection value and the average speed of drilling fluid loss to the stratum. The second calculation judgment subunit may receive a judgment result of the first calculation judgment subunit, and calculate a drilling fluid loss position where a lost circulation formation exists.
In this embodiment, the first calculation determination subunit is capable of determining whether there is a lost circulation in the well depth according to the following formula:
according to the formula
Comparison D e With a threshold value delta, if D e If D is less than or equal to delta, judging that no leakage exists in the well depth, and if D is less than or equal to delta e If the well depth is larger than delta, the well leakage exists at the well depth, wherein GR 1 For the first gamma detection point at the well depth, GR 2 For the second gamma valueAnd (4) detecting the detection value of the measuring point at the well depth, wherein the threshold value delta is a given value. The threshold δ may be related to a volume conversion coefficient α of the radioactive indicator drilling fluid gamma value. The threshold value δ may be confirmed in experimentally determining the volume conversion coefficient α. For example, the threshold δ may be chosen, empirically, between 0.2 and 0.5.
In this embodiment, the determining, by the first calculating and determining subunit, whether the lost circulation exists in the formation to be detected includes:
at a certain well depth in the stratum to be detected, the first calculation and judgment subunit compares the detection value obtained by the near-end probe with the detection value obtained by the far-end probe, and if the detection value of the near-end probe is equal or approximately equal to the detection value of the far-end probe, the first calculation and judgment unit judges that no well leakage occurs at the well depth;
and if the detection value of the far-end probe is larger than that of the near-end probe, the first calculation judgment subunit judges that the well leakage is suspected to occur at the well depth. And the first calculation judgment subunit further calculates the speed of the drilling fluid lost to the stratum at the well depth. And comparing the speed with a standard for judging the well leakage in the industry, and if the speed is greater than a well leakage standard value, judging that the well leakage occurs at the well depth by the first calculation judging subunit. As described above, the second detection value being approximately equal to the first detection value may be a detection value in which the first detection value and the second detection value differ by a range of 2% or less.
For example, at a certain well depth the proximal probe reaches the well depth and detects the well depth with a detection value x j . The far-end probe reaches the well depth and the detection value of the well depth detection is x y . The vertical distance between the proximal probe and the distal probe is L.
(1) For the case of normal drilling without lost circulation at the well depth, x j ＝x y 。
(2) During drilling, well leakage occurs at the deep part of the well for the first time; if there is x at this time j ＜x i And judging that the well leakage is suspected to occur at the well depth.
For the well depth which is judged to be suspected of lost circulation, whether the well depth finally has lost circulation or not can be judged by further determining whether the suspected lost circulation occurrence part meets the standards of lost circulation or not.
If the well leakage occurs at a certain well depth of the stratum, when the near-end probe reaches the well depth to be detected, a first detection value detected by the near-end probe is recorded as GR 1 When the far-end probe reaches the well leak point, the second detection value detected by the far-end probe is recorded as GR 2 Then, there are:
GR 1 ＝GR 2 -b；
where b is a constant representing the difference between the second detection value and the first detection value.
The rate at which the well depth drilling fluid is lost to the formation can be calculated by the following formula:
wherein Q is the speed of the drilling fluid lost to the stratum at the well depth; GR 1 Representing a first detection value; GR 2 Indicating a second detected value; alpha is a volume conversion coefficient containing the gamma value of the current concentration radioactive indicator drilling fluid, and the alpha value can be determined by experiments; t represents the time elapsed from the proximal probe to the distal probe to reach the depth of the well. The alpha value is the conversion relation between the gamma value corresponding to the radioactive indicator of the drilling fluid with different concentrations and volumes of the indicator and the actual volume of the drilling fluid, and the conversion coefficients corresponding to the radioactive indicators with different concentrations and volumes are different. For those skilled in the art, a gamma value is recorded as a function of the indicator concentration and the volume of drilling fluid to obtain an alpha value.
In this embodiment, the system further comprises a lost circulation determination unit. The lost circulation section determination unit may be connected to the first calculation and determination subunit. The lost circulation section determining unit can receive a judgment result of whether lost circulation exists in each well depth or not by the first calculation judgment subunit. If the first calculation and determination subunit determines that the lost circulation exists at a plurality of continuous well depths, the lost circulation section determination unit can determine that the plurality of well depths form a lost circulation section. And calculating the length of the lost circulation section according to the set distance between the adjacent well depths. For example, in the logging-while-drilling process, 1m is used as the interval of each detection point, then the lost circulation determination is performed every 1m, after the determination of multiple detection points, there may be a plurality of detection points all determined as lost circulation, then the length of the lost circulation section is the product of the number of the detection points and 1m, and the length of the lost circulation section can be finally calculated.
Further, the system may further include a drop-out strength determination unit. The leakage strength determination unit can compare the average speed of the drilling fluid leaked to the stratum in the lost circulation section with a standard value of the lost circulation strength to determine the leakage strength, and the leakage strength determination unit calculates the average speed of the drilling fluid leaked to the stratum according to the following formula:
wherein the content of the first and second substances,
the average speed of the drilling fluid in the lost circulation section leaking to the stratum is obtained;
the average value of the detection values of the second gamma value detection points at each well depth in the lost circulation section is obtained;
the average value of the detection values of the first gamma value detection points at each well depth in the lost circulation section is obtained; alpha is the volume conversion coefficient of the gamma value of the drilling fluid containing the radioactive indicator of the current concentration. For T, for example, when it is determined that lost circulation exists at the first well depth, the second well depth, the third well depth, and the fourth well depth which are continuous and increasing in depth. The lost circulation segment is the location from the first well depth to the fourth well depth. The time T from the first gamma value detection point reaching the first well depth of the lost circulation section to the second gamma value detection point reaching the first well depth of the lost circulation section 1 The time T from the first gamma value detection point reaching the second well depth of the well leakage section to the second gamma value detection point reaching the second well depth of the well leakage section 2 First, aThe time T from the gamma value detection point reaching the third well depth of the lost circulation section to the second gamma value detection point reaching the third well depth of the lost circulation section 3 And the time T from the first gamma value detection point reaching the fourth well depth of the lost circulation section to the second gamma value detection point reaching the fourth well depth of the lost circulation section 4 . T is time T 1 、T 2 、T 3 And T 4 Average value of (T) 1 、T 2 、T 3 And T 4 Divided by 4).
The resulting average rate of loss of drilling fluid to the formation was compared to the standard values in the table below to determine the loss strength, wherein the loss strength rating table is shown in table 1.
TABLE 1 leakage intensity grading Table
| Level of drop-out | First level | Second order | Three-stage | Four stages | Five stages |
| Leakage velocity/(m) 3 /h) | ≤5 | 5～15 | 15～30 | 30～60 | ≥60 |
| Description of the degree | Micro-leakage | Small leak | Middle leakage | Large leak | Severe loss of fluid |
In this embodiment, the second calculation and determination subunit can calculate the drilling fluid loss while drilling position according to the following formula:
H k ＝P-L，
wherein H k Determining the well depth with the well leakage for the first time; p is the well depth of the drill bit when the far-end probe detects the abnormal well leakage; and L is the distance from the drill bit to the far point probe.
In this embodiment, as shown in fig. 1, the system may further include a concentration adjusting unit. The concentration adjustment unit may be connected to a detector. The concentration adjustment unit may include a concentration monitor, the concentration adjustment unit being capable of adjusting the concentration of the radioactive indicator in the drilling fluid to ensure that the indicator concentration in the drilling fluid is at or above a minimum value at which the detector is capable of detecting the indicator concentration. During the drilling process, the drilling fluid may be affected by lost circulation, surface manifold deposition, downhole drilling tool adhesion, and open channel loss caused by the flow of the drilling fluid, such as a vibrating screen, etc., and the radioactive indicator added in the drilling fluid may be lost, thereby reducing the detected effect and possibly affecting the data analysis and application of the subsequent steps. Thus, the indicator concentration in the drilling fluid is detected and replenished during or after drilling to ensure that the indicator concentration in the drilling fluid reaches the minimum concentration value detectable at the detection point. And, in order to make the detection more accurate, to different stratum, concentration adjustment unit can adjust the radioactive indicator concentration in the drilling fluid.
In this embodiment, the system may further include a radioactive indicator storage unit and a radioactive indicator switching unit. Wherein the radioactive indicator storage unit may be connected to a concentration adjustment unit. The radioactive indicator storage unit is capable of storing a plurality of types of radioactive indicators. The radioactive indicator storage unit can add the radioactive indicator to the drilling fluid before detecting the lost circulation, and can add the radioactive indicator to the drilling fluid according to the feedback condition of the concentration adjusting unit. And if the concentration in the drilling fluid needs to be adjusted to be high due to the fact that the concentration in the drilling fluid is fed back to the concentration adjusting unit to be low, the radioactive indicator is added into the drilling fluid. The radioactive indication switching unit is connected with the radioactive indicator storage unit. The radioactive indicator switching unit can switch the type of the indicator added to the radioactive indicator storage unit according to the formation property.
In the above, the type of the radioactive indicator can be determined according to the property of the formation to be detected, and can be adjusted according to different formation properties. Different types of indicators can be optionally added into the drilling fluid to realize switching according to different strata in the process of detecting lost circulation. The radioactive indicator may be a radioactive hydrogen series element. Of course, the kind of the radioactive indicator of the present invention is not limited thereto.
The amount of radioactive indicator added is related to the nature of the formation being tested and may be adjusted according to the particular formation being tested. The radioactive indicator storage unit can determine the minimum adding amount of the radioactive indicator according to the minimum concentration value detected by the detector, the total volume of the downhole circulation and the drilling fluid to be pumped on the ground. For example, the minimum added dose of the radioactive indicator can be determined by:
through simulation experiments, namely in saturated drilling fluid which is closed at the earth surface and is not influenced by environmental radioactivity and electromagnetism, the detector can detect the volume percentage concentration M of the lowest dosage of the added radioactive indicator gg . Setting the total volume of the part to be pumped at the surface and circulated in the well bore to be pumped as U (the total volume of the drilling fluid to be pumped at the surface and circulated in the well bore), the minimum adding dosage M of the radioactive indicator g Can be as follows:
M g ＝M gg ·U。
if quantitative dosing of the indicator additive is required without test and detection conditions, the dosage of the additive per liter of drilling fluid can be determined by testing. According to the difference requirement of the radioactive indicator and the stratum to be measured, the adding amount of the radioactive indicator can be determined according to the stratum characteristics, the additive difference condition and the well bore volume condition in the drilling process. If a radioactive indicator with a mass concentration of 100Mg/L is required to be added, the total mass of Mg =100 XU =100U Mg resident in the well bore, wherein U is the total volume of the drilling fluid circulated in the well and pumped on the surface.
In this embodiment, in order to better detect the change of the radioactive indicator in the drilling fluid, the difference coefficient between the radioactive indicator and the formation to be detected needs to be greater than 0.2, and the difference coefficient is:
wherein D is g Representing the coefficient of difference, G, of the radioactive indicator from the formation t Represents the natural radioactivity of the radioactive indicator; g d Representing the average number of natural radioactivity in the formation.
In this embodiment, the volume percentage concentration of the radioactive indicator is detected, and the concentration adjustment unit can adjust the concentration of the radioactive indicator in the drilling fluid if the concentration is not detected by the detector: (1) at the completion of 30 or about 30 cycles; (2) before and after the drilling fluid is treated; (3) deviation of more than 20% occurs between the instrument reading and manual counting; (4) Situations occur where a large scale oil and gas water leak display occurs, including drilling fluid lost circulation.
In this embodiment, the detection range of the detector may be the outer annular space between the outside of the drilling tool and the cutting surface of the formation exposed after being fractured by the drill bit, and the content of the indicating additive changes within a range of the formation with a depth of 30 cm (e.g., 20 cm) (radioactive).
In the embodiment, the system is suitable for judging the well leakage condition of the drilling stratum and actively detecting the condition that drilling fluid leaks into the stratum while drilling.
In this embodiment, the time of the occurrence of the lost circulation at the well depth to be detected should be later than the time of the near-end probe reaching the well depth to be detected.
In this embodiment, if the clay content of the formation to be detected is abnormally increased, the rising slope of the curve drawn by the detection values of the detection points in the whole detection process is smooth, and the data detected by the far-end probe is consistent with the change slope of the curve of the data detected by the near-end probe.
In this embodiment, the system may further include a total drilling fluid amount monitoring unit and a loss type determination unit. The total drilling fluid amount monitoring unit can monitor the total volume of the drilling fluid which circulates underground and is to be pumped on the ground. The leakage type determining unit can be respectively connected with the drilling fluid total amount monitoring unit and the first calculation judging subunit, and can judge whether the drilling fluid total amount volume changes or the leaking layer leaks again according to the well leakage condition of the well depth to be detected. If the well depth to be detected judges that the well leakage exists, the well leakage occurs on the drilling layer; if the well depth to be detected judges that no well leakage exists but the drilling fluid is abnormally reduced, the occurrence of the leakage layer re-leakage can be judged.
In conclusion, the system can realize the active detection of the position and the leakage intensity of the lost circulation, and has high lost circulation finding speed and short delay time; the type and the concentration of the radioactive indicator can be adjusted and replaced according to different stratum properties, the detection is accurate and flexible, and the position of the lost circulation is judged directly; the well leakage of the positive drill floor and the re-leakage of the leaking floor can be judged, and whether the re-leakage occurs can be determined.
Although the present invention has been described above in connection with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (9)
1. A system for active detection of lost circulation using radioactive indicators, characterized in that the system comprises a detector and a computational decision unit, wherein,
the detector is arranged on the drilling tool close to the drill bit and comprises a near-end probe and a far-end probe which are sequentially arranged in the opposite drilling direction, and the near-end probe and the far-end probe can sequentially pass through the same well depth at different moments and detect the gamma value of the radioactive indicator at the well depth;
the calculation judging unit comprises a first calculation judging subunit and a second calculation judging subunit which are connected with each other, the first calculation judging subunit respectively receives the detection values obtained by the near-end probe and the far-end probe and judges whether the well depth has the lost circulation according to the change conditions of the detection value of the near-end probe and the detection value of the far-end probe, and the second calculation judging subunit receives the judgment result of the first calculation judging subunit and calculates the drilling fluid loss while drilling under the condition that the lost circulation is judged to exist;
the first calculation judgment subunit calculates the speed of the drilling fluid lost to the stratum at the well depth according to the following formula:
wherein Q is the speed of the drilling fluid lost to the stratum at the well depth; GR 1 Representing a first detection value; GR 2 Indicating a second detected value; t represents the time elapsed from the proximal probe to the distal probe to reach the well depth; alpha is the volume conversion coefficient of the gamma value of the radioactive indicator drilling fluid containing the current concentration;
the first detection value and the second detection value sequentially reach the well depth through a first gamma value detection point of the near-end probe and a second gamma value detection point of the far-end probe, and the gamma value of the radioactive indicator at the well depth is detected.
2. The system for radioactive indicator active detection of lost circulation according to claim 1, wherein said second calculation determination subunit is capable of calculating the location of drilling fluid loss while drilling according to the following formula:
H k ＝P-L，
wherein H k Determining the well depth with the well leakage for the first time; p is the well depth of the drill bit when the remote probe detects the abnormal well leakage; and L is the distance from the drill bit to the far point probe.
3. The system for radioactive indicator active detection of lost circulation according to claim 1, wherein said first calculation determination subunit is capable of determining whether there is lost circulation at the well depth according to the following formula:
comparison D e With a threshold value delta, if D e If the well depth is less than or equal to delta, judging that no well leakage exists in the well depth,
if D is e If the well depth is larger than delta, determining that the well leakage exists at the well depth, wherein GR 1 For the first gamma detection point at the well depth, GR 2 The detection value of the second gamma value detection point at the well depth is shown, and the threshold value delta is a given value.
4. The active radioactive indicator lost circulation system according to claim 1, wherein the first calculation determining subunit determines whether a lost circulation exists in the formation to be examined comprises:
the first calculation judgment subunit compares the near-end probe detection value with the far-end probe detection value, and if the near-end probe detection value and the far-end probe detection value are equal or approximately equal at the same well depth, the first calculation judgment subunit judges that the well depth does not generate well leakage;
if the detection value of the far-end probe is larger than that of the near-end probe, the first calculation judgment subunit judges that the well depth is suspected to generate the well leakage, the first calculation judgment subunit calculates the speed of the well depth drilling fluid leaking to the stratum, and if the speed is larger than a well leakage standard value, the well leakage is judged to occur.
5. The system for actively detecting lost circulation by using radioactive indicators as claimed in claim 1, further comprising a lost circulation section determining unit, wherein said lost circulation section determining unit is connected to said first calculating and judging subunit, and is configured to receive the judgment result of whether lost circulation exists at each well depth from said first calculating and judging subunit, and determine that lost circulation exists at a plurality of well depths according to the judgment result, if the plurality of well depths continuously exist, and determine that the plurality of well depths constitute a lost circulation section.
6. The active radioactive indicator lost circulation system according to claim 5, further comprising a lost circulation strength determination unit capable of determining a lost circulation strength by comparing an average rate of drilling fluid loss to the formation in the lost circulation section with a lost circulation strength standard value, wherein the lost circulation strength determination unit calculates the average rate of drilling fluid loss to the formation according to the following formula:
wherein, the first and the second end of the pipe are connected with each other,
the average speed of the drilling fluid in the lost circulation section leaking to the stratum is obtained;
the average value of the detection values of the second gamma value detection points at each well depth in the lost circulation section is obtained;
the average value of the detection values of the first gamma value detection points at each well depth in the lost circulation section is obtained;
indicating wellThe average value of the time from the first gamma value detection point to the second gamma value detection point of each well depth in the leakage section to the well depth; alpha is the volume conversion coefficient of the gamma value of the radioactive indicator drilling fluid containing the current concentration.
7. The system for radioactive indicator active detection of lost circulation according to claim 1, further comprising a concentration adjustment unit connected to said detector, said concentration adjustment unit comprising a concentration monitor, said concentration adjustment unit for adjusting the radioactive indicator concentration in the drilling fluid to ensure that the gamma value of the radioactive indicator in the drilling fluid is above a minimum gamma value detectable by the detector and to enable adjustment of the radioactive indicator concentration according to the formation properties.
8. The active radioactive indicator lost circulation system according to claim 7, further comprising a radioactive indicator storage unit and a radioactive indicator switching unit, wherein,
the radioactive indicator storage unit is connected with the concentration adjusting unit, can store various types of radioactive indicators and can add the radioactive indicators into the drilling fluid before the well leakage is detected and according to the feedback condition of the concentration adjusting unit;
the radioactive indicator switching unit is connected with the radioactive indicator storage unit and can switch the type of the radioactive indicator added into the radioactive indicator storage unit according to the stratum properties.
9. The system for radioactive indicator active detection of lost circulation of wellbore of claim 8, wherein the radioactive indicator storage unit is capable of determining an initial radioactive indicator loading based on a minimum concentration value that can be monitored by the concentration monitor, as well as downhole circulation and total volume of drilling fluid to be pumped at surface.
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| CN2019106716291 | 2019-07-24 | ||
| CN201910671629.1A CN110454151A (en) | 2019-07-24 | 2019-07-24 | Enter the active detection method of strata condition with brill drilling fluid leakage |
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| CN201910671629.1A Pending CN110454151A (en) | 2019-07-24 | 2019-07-24 | Enter the active detection method of strata condition with brill drilling fluid leakage |
| CN201911397888.6A Active CN110924938B (en) | 2019-07-24 | 2019-12-30 | Well leakage while drilling active detection system with high accuracy |
| CN201911398164.3A Active CN110905487B (en) | 2019-07-24 | 2019-12-30 | High-accuracy well leakage active comprehensive detection method |
| CN201911398328.2A Active CN110847897B (en) | 2019-07-24 | 2019-12-30 | Method for actively detecting lost circulation by using radioactive indicator |
| CN201911396906.9A Active CN110863820B (en) | 2019-07-24 | 2019-12-30 | System for detecting lost circulation while drilling by adopting conductive indicating additive |
| CN201911398002.XA Active CN110847896B (en) | 2019-07-24 | 2019-12-30 | Active detection method for lost circulation while drilling with high accuracy |
| CN201911397085.0A Active CN110863821B (en) | 2019-07-24 | 2019-12-30 | Method for detecting lost circulation while drilling by using low-conductivity indicating additive |
| CN201911403339.5A Active CN110872948B (en) | 2019-07-24 | 2019-12-30 | System for actively detecting lost circulation by utilizing radioactive indicator |
| CN201911397357.7A Active CN110905486B (en) | 2019-07-24 | 2019-12-30 | Method for detecting lost circulation while drilling by using high-conductivity indicating additive |
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| CN201910671629.1A Pending CN110454151A (en) | 2019-07-24 | 2019-07-24 | Enter the active detection method of strata condition with brill drilling fluid leakage |
| CN201911397888.6A Active CN110924938B (en) | 2019-07-24 | 2019-12-30 | Well leakage while drilling active detection system with high accuracy |
| CN201911398164.3A Active CN110905487B (en) | 2019-07-24 | 2019-12-30 | High-accuracy well leakage active comprehensive detection method |
| CN201911398328.2A Active CN110847897B (en) | 2019-07-24 | 2019-12-30 | Method for actively detecting lost circulation by using radioactive indicator |
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| CN201911398002.XA Active CN110847896B (en) | 2019-07-24 | 2019-12-30 | Active detection method for lost circulation while drilling with high accuracy |
| CN201911397085.0A Active CN110863821B (en) | 2019-07-24 | 2019-12-30 | Method for detecting lost circulation while drilling by using low-conductivity indicating additive |
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| CN112112633A (en) * | 2020-09-30 | 2020-12-22 | 中国石油天然气集团有限公司 | Drilling stratum leak source measuring instrument and judging method |
| CN112211619A (en) * | 2020-11-19 | 2021-01-12 | 中国石油天然气集团有限公司 | Method for rapidly determining lost circulation position in long open hole section |
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| US4861986A (en) * | 1988-03-07 | 1989-08-29 | Halliburton Logging Services, Inc. | Tracer injection method |
| CN1060247C (en) * | 1997-05-07 | 2001-01-03 | 石油大学(北京) | Method and apparatus for measuring position of mud loss |
| US6441618B2 (en) * | 2000-02-04 | 2002-08-27 | Schlumberger Technology Corporation | Method and apparatus for monitoring the advance of seawater into fresh water aquifers near coastal cities |
| US6694262B2 (en) * | 2000-03-31 | 2004-02-17 | Alexander T. Rozak | Method for determining geologic formation fracture porosity using geophysical logs |
| GB2445159B (en) * | 2006-12-23 | 2009-11-18 | Schlumberger Holdings | Methods and systems for determining mud flow velocity from measurement of an amplitude of an artificially induced radiation |
| US8499828B2 (en) * | 2009-12-16 | 2013-08-06 | Schlumberger Technology Corporation | Monitoring fluid movement in a formation |
| US8669516B2 (en) * | 2010-08-20 | 2014-03-11 | Baker Hughes Incorporated | Using LWT service to identify loss circulation areas in a wellbore |
| US20130160998A1 (en) * | 2011-12-23 | 2013-06-27 | Francois M. Auzerais | Lost Circulation Materials and Methods of Using Same |
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