A drilling fluid density measuring device and method

Abstract

The application discloses a kind of drilling fluid density measuring device and measuring method, wherein the measuring device includes: measuring tube component, including main measuring tube, counterweight column and plug head, the main measuring tube has the accommodation cavity of columnar and top opening in it, the counterweight column is slidably arranged at the bottom of accommodation cavity, the plug head is located at the top of main measuring tube and is inserted in accommodation cavity, the outside wall of main measuring tube has scale structure;Slowly descending mechanism is connected with a supporting table, and can drive supporting table to move up and down, main measuring tube is worn in slowly descending mechanism, and the bottom of main measuring tube abuts supporting table.By slowly descending mechanism can be guided to main measuring tube, to ensure that it moves vertically, and by controlling slowly descending mechanism can drive supporting table to descend more slowly, so that it can avoid main measuring tube to jump in drilling fluid, avoid the position that the surface of main measuring tube corresponds to the position above the liquid level of drilling fluid is contaminated with drilling fluid, ensure that personnel can accurate reading, so that it can improve measurement accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drilling fluid density measurement, in particular to a drilling fluid density measurement device and a measurement method. BACKGROUND

[0002] In geological exploration drilling construction, the basic functions of drilling fluid mainly include drilling slag discharge, hole wall protection, cooling and lubrication, and ground pressure balance. In order to achieve the above purposes, drilling construction technical personnel need to master the drilling fluid density and other related parameters.

[0003] The traditional drilling fluid density measurement tool is composed of a balance, a measuring cup and a measuring spoon. Professional technical personnel are often required to implement the drilling fluid density measurement, which is usually measured once every several tens of minutes to several hours, consuming a large amount of manpower, and cannot provide continuous recording data of mud density. It is also inconvenient to dynamically master the change of mud density during drilling. Using pressure sensor principle to calculate mud density requires high professional technology and large economic cost, which is difficult for machine site personnel to complete. As one of the core parameter indexes of drilling fluid, the machine urgently needs simple and intuitive measuring instruments to timely master the drilling fluid density parameters in the drilling process of the machine, to realize dynamic control of drilling fluid quality, and to improve drilling construction efficiency.

[0004] In addition, for the measurement of liquid density, a structure of a buoyancy type liquid level meter is also used (such as CN87215185 buoyancy density meter and CN213714989U a counterweight adjustable density meter). Specifically, the float tube is placed into the liquid by hand, and after the float tube is stable, the density of the liquid to be measured can be obtained by reading the scale corresponding to the liquid surface of the float tube. However, when applied to drilling fluid density measurement, the speed of placing the float tube by hand is relatively fast, and it is difficult for the hand to place the float tube vertically. The float tube needs to jump up and down several times in the drilling fluid to stabilize due to the need for a balance process of gravity and buoyancy. After the float tube is stable, the surface of the float tube above the position corresponding to the liquid surface of the drilling fluid will also be contaminated with the drilling fluid. For the drilling fluid, since its color is deep, the adhesion to the surface of the float tube above the position corresponding to the liquid surface of the drilling fluid can easily affect the reading, thereby resulting in low measurement accuracy. SUMMARY

[0005] The purpose of the present application is to provide a drilling fluid density measurement device which can reduce the influence of drilling fluid adhesion on reading and improve measurement accuracy.

[0006] The present application also provides a drilling fluid density measurement method based on the above measurement device.

[0007] According to the first aspect of the present application, a drilling fluid density measurement device is provided, which comprises:

[0008] The measuring tube assembly comprises a main measuring tube, a weight column and a plug, the main measuring tube has a cylindrical accommodating cavity with an open top inside, the weight column is slidably arranged at the bottom of the accommodating cavity, and the plug is arranged at the top of the main measuring tube and inserted into the accommodating cavity; the outer sidewall of the main measuring tube has a scale structure.

[0009] The slow descent mechanism is connected with a supporting table and can drive the supporting table to move up and down, the main measuring tube is arranged in the slow descent mechanism, and the bottom of the main measuring tube abuts against the supporting table.

[0010] When the main measuring tube and the supporting table are inserted into the drilling fluid and move downwards, the main measuring tube is driven to move upwards relative to the supporting table by buoyancy, so that the main measuring tube is separated from the abutment with the supporting table.

[0011] According to the drilling fluid density measuring device, the bottom of the main measuring tube is arranged in a semispherical shape.

[0012] According to the drilling fluid density measuring device, the main measuring tube is made of acrylic material, and the weight column is made of stainless steel.

[0013] According to the drilling fluid density measuring device, the scale structure comprises a first scale and a second scale, the first scale is used for indicating the drilling fluid density, and the second scale is used for indicating the length of the main measuring tube exposed to air or the draught of the main measuring tube in the drilling fluid.

[0014] According to the drilling fluid density measuring device, the slow descent mechanism comprises a support, a vertical support rod slidably arranged in the support, a rack arranged on one side of the support rod, the supporting table arranged at the bottom of the support rod, a gear arranged inside the support and engaged with the rack, a knob rotatably arranged in the support and connected with the gear, a guide cylinder arranged in the support and having a plurality of balls and a first guide groove arranged inside, the balls arranged above the first guide groove, the main measuring tube arranged in the guide cylinder and in contact with the balls, the first guide groove arranged in two or more than two and arranged around the main measuring tube and inclined to the main measuring tube, a scraping block slidably arranged in each first guide groove and having an arc-shaped rubber scraping strip arranged inside, a push plate slidably sleeved on the support rod and extending below the scraping block, and a spring member sleeved on the support rod and connected between the push plate and the supporting table; the support rod has a mark position, and when the bottom of the main measuring tube abuts against the supporting table, the mark position is flush with the top edge of the plug.

[0015] According to the drilling fluid density measuring device, the balls are arranged in a plurality of groups arranged above and below, each group has at least three balls arranged around the main measuring tube.

[0016] According to the drilling fluid density measuring device, the second guide groove is provided with a limiting piece, and the limiting piece is slidable in the second guide groove and is inserted into the rack.

[0017] According to the drilling fluid density measuring device, the first magnetic block is arranged at one end of the second guide groove away from the support rod, the second magnetic block is arranged on the side of the limiting piece away from the support rod, the third magnetic block is arranged in the second guide groove, the magnetic pole directions of the first magnetic block and the second magnetic block are arranged along the second guide groove, and the magnetic pole direction of the third magnetic block is inclined to the first magnetic block.

[0018] When the limiting piece is slid to make the third magnetic block located between the first magnetic block and the second magnetic block, the second magnetic block and the third magnetic block can repel each other; and when the limiting piece is slid to make the second magnetic block located between the first magnetic block and the third magnetic block, the second magnetic block and the first magnetic block can attract each other.

[0019] According to a second aspect of the present application, a drilling fluid density measuring method is provided, which is based on the drilling fluid density measuring device and comprises the following steps.

[0020] S1, detection preparation: the measuring device is assembled, the support is installed in the mud pool containing the drilling fluid, the support rod and the main measuring tube are adjusted, so that the bottom of the main measuring tube abuts against the supporting table, the mark position is flush with the top edge of the plug, the push plate is not in contact with the scraping block, and the bottom of the main measuring tube is located at a first standby position higher than the liquid level;

[0021] S2, lowering the support rod: the knob is forwardly rotated, the support rod is driven to move downward through the meshing transmission of the gear and the rack, and after the supporting table contacts the liquid level of the drilling fluid, the downward movement speed of the support rod is controlled to be not more than 5 mm / s;

[0022] S3, detection reading: after the mark position starts to be lower than the top edge of the plug, the support rod is continuously moved downward to make the height difference between the top edge of the plug and the mark position be at least 20 mm, after the main measuring tube is stable, the position of the liquid level on the scale structure is observed, and the scale structure is read;

[0023] S4, dynamic observation: every interval of a set time, the position of the liquid level on the scale structure is observed, and the scale structure is read;

[0024] S5, upward movement and cleaning: the knob is reversely rotated, the supporting table and the main measuring tube are moved upward, the push plate first contacts the scraping block and drives the scraping block to move upward, the rubber scraping strip is attached to the outer side wall of the main measuring tube, the bottom of the main measuring tube is moved to a second standby position, the knob is forwardly rotated, and the rotation of the knob is stopped after the supporting table is separated from the bottom of the main measuring tube, the limiting piece is moved to be inserted into the rack, and the liquid on the part of the main measuring tube below the rubber scraping strip and the liquid at the bottom of the rubber scraping strip are wiped off.

[0025] The second standby position is higher than the first standby position.

[0026] In S5, when the supporting table is out of contact with the bottom of the main measuring tube, the spring member is in a compressed state.

[0027] Advantages:

[0028] 1. The main measuring tube is arranged in the slow descent mechanism, and the main measuring tube can be guided by the slow descent mechanism to ensure vertical movement, and the supporting table can be driven to slowly descend by controlling the slow descent mechanism, so that the main measuring tube can be prevented from jumping in the drilling fluid, the surface of the main measuring tube corresponding to the position above the liquid level of the drilling fluid can be prevented from being contaminated with drilling fluid, and personnel can accurately read the data, thereby improving the measurement accuracy; the plug can prevent liquid and other impurities from entering the main measuring tube.

[0029] 2. By floating the measuring tube assembly in the drilling fluid, the density change of the drilling fluid can be understood in time, and the reading can be performed in time to obtain the dynamic density data of the drilling fluid.

[0030] 3. The slow descent mechanism can clean the liquid adhered to the part of the main measuring tube above the liquid level, facilitating reading.

[0031] Additional aspects and advantages of the application will be described in part below, will become apparent from the following description, or will be learned by practicing the application. BRIEF DESCRIPTION OF DRAWINGS

[0032] The application will be further described below in combination with the drawings and examples.

[0033] Figure 1 It is a structural view of the measuring tube assembly.

[0034] Figure 2 It is a sectional view of the measuring tube assembly.

[0035] Figure 3 It is a sectional view of the drilling fluid density measuring device in the first working state.

[0036] Figure 4 It is a sectional view of the drilling fluid density measuring device in the second working state.

[0037] Figure 5 It is a sectional view of the drilling fluid density measuring device in the third working state.

[0038] Figure 6 It is a sectional view of the drilling fluid density measuring device in the fourth working state.

[0039] Figure 7 It is a sectional view of the drilling fluid density measuring device in the fourth working state. Figure 6 It is an enlarged view of part A shown in the figure.

[0040] Figure 8 is an enlarged view of the B part shown in FIG. 1; Figure 6 is an enlarged view of the B part shown in FIG. 1;

[0041] Figure 9 is a sectional view of the support rod;

[0042] Figure 10 is a first sectional view of the second guide groove and the limiting member;

[0043] Figure 11 is a second sectional view of the second guide groove and the limiting member. DETAILED DESCRIPTION

[0044] This part will describe the specific embodiments of the present application in detail, the preferred embodiments of the present application are shown in the drawings, the role of the drawings is to supplement the description of the text part with graphics, so that people can intuitively and visually understand each technical feature and the overall technical solution of the present application, but it cannot be understood as a limitation on the protection scope of the present application.

[0045] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the present application.

[0046] In the description of the present application, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the sequence of technical features indicated.

[0047] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be understood broadly, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0048] Referring to Figures 1-11The application discloses a drilling fluid density measuring device which comprises a measuring pipe assembly 10 and a slow descent mechanism 20, the measuring pipe assembly 10 comprises a main measuring pipe 11, a weight column 12 and a plug 13, the main measuring pipe 11 is internally provided with a columnar accommodating cavity 14 which is open at the top, the weight column 12 is slidably arranged at the bottom of the accommodating cavity 14, the plug 13 is arranged at the top of the main measuring pipe 11 and is inserted into the accommodating cavity 14, and the outer side wall of the main measuring pipe 11 is provided with a scale structure. The slow descent mechanism 20 is connected with a supporting table 30, the slow descent mechanism 20 can drive the supporting table 30 to move up and down, the main measuring pipe 11 is arranged in the slow descent mechanism 20, and the bottom of the main measuring pipe 11 abuts against the supporting table 30. The accommodating cavity 14 and the weight column 12 are both arranged in a cylindrical shape, so that the weight of the measuring pipe assembly 10 is uniformly distributed.

[0049] In use, the slow descent mechanism 20 is fixedly arranged in a mud pool containing drilling fluid, the supporting table 30 is slowly lowered by using a driving mechanism, and the main measuring pipe 11 also follows the lowering under the action of gravity; when the main measuring pipe 11 and the supporting table 30 are inserted into the drilling fluid, the main measuring pipe 11 is driven to move upwards relative to the supporting table 30 by using buoyancy, so that the main measuring pipe 11 is separated from the abutment with the supporting table 30, the measuring pipe assembly 10 floats in the drilling fluid, and the density of the drilling fluid can be obtained by observing the position of the liquid surface in the scale structure. The main measuring pipe 11 is arranged in the slow descent mechanism 20, the slow descent mechanism 20 can guide the main measuring pipe 11, so that the vertical movement of the main measuring pipe 11 is ensured, the slow descent mechanism 20 can drive the supporting table 30 to slowly descend, so that the main measuring pipe 11 can not jump in the drilling fluid, the surface of the main measuring pipe 11 corresponding to the position above the liquid surface of the drilling fluid can not be contaminated by the drilling fluid, the personnel can accurately read the data, and the measurement accuracy can be improved. In addition, the plug 13 can prevent liquid and other sundries from entering the main measuring pipe 11.

[0050] The bottom of the main measuring pipe 11 is arranged in a semispherical shape, the main measuring pipe 11 is made of acrylic material, and the weight column 12 is made of stainless steel. The acrylic material has good corrosion resistance and smoothness, the bottom of the main measuring pipe 11 is semispherical and tangent to the outer side wall, and the influence of the viscosity of the drilling fluid on the measurement accuracy is reduced. The weight column 12 made of stainless steel with large density is arranged in the accommodating cavity 14, the measuring pipe assembly 10 is light at the top and heavy at the bottom, and the bottom is automatically guided to be perpendicular to the drilling fluid.

[0051] In the embodiment, the scale structure comprises a first scale 151 and a second scale 152, the first scale 151 is used for indicating the density of the drilling fluid, and the second scale 152 is used for indicating the length of the main measuring pipe 11 exposed to air or the draught of the main measuring pipe 11 in the drilling fluid.

[0052] The calibration of the first scale 151 and the second scale 152 is as follows.

[0053] Initial formula:

[0054]

[0055] Conversion formula:

[0056] Wherein, T1 is the weight of the main measuring tube 11, T2 is the weight of the plug 13, T3 is the weight of the counterweight column 12, V is the displacement of the main measuring tube 11 when it is stabilized in the drilling fluid, r is the outer diameter of the main measuring tube 11, and H is the draught of the main measuring tube 11 when it is stabilized in the drilling fluid (i.e. the height difference between the bottom edge of the main measuring tube 11 and the liquid surface of the drilling fluid). Based on the above formula, the first scale 151 and the second scale 152 can be calibrated.

[0057] For example, the diameter of the main measuring tube 11 is 40 mm, the total length is 640 mm, the accommodating cavity has a diameter of 30 mm and a length of 60 mm, the density is 1.19 g / cm 3 , the length of the counterweight column is 45 mm, the diameter is 28 mm, the density is 7.93 g / cm 3 , the weight of the plug is 8 g, and π is 3.14159. After unit conversion, the relationship between H and ρ is shown in the following table based on the calculation.

[0058] Table 1 Relationship between H and ρ

[0059]

[0060]

[0061] The parameter settings of the measuring tube assembly 10 need to consider the three elements of carrying, the depth of the drilling fluid in the conventional mud pit, and visual observation. As can be seen from the table, using the above parameters, the reading scale calibration section has a total length of 25.5 cm for measuring the drilling fluid with a density in the range of 0.90 g / cm 3 ~ 1.60 g / cm 3 , and the scale interval is 2.1 mm ~ 6.4 mm for every 0.01 g / cm 3 increase in the density of the drilling fluid, the scale interval is 3.7 mm ~ 5.3 mm for every 0.01 g / cm 3 change in the high-frequency use section (drilling fluid density 1.00 g / cm 3 ~ 1.20 g / cm 3 ), which ensures the accuracy of direct observation in the field. The field drilling technicians can observe it with the naked eye, and the accuracy can reach 0.01 g / cm 3 , which can meet the requirements of dynamic monitoring and management of the drilling fluid density during the drilling construction process.

[0062] In order to further enhance the convenience of observation, the scale lines of the scale structure are marked by using corrosion-resistant golden yellow material, and the golden yellow material marking scale lines increases the color contrast with the drilling fluid, so as to facilitate personnel to read. In order to be able to observe the drilling fluid density of multiple parts such as mud pool and circulating pool at the same time, six groups of measuring devices can be matched as a box, and a conventional handheld magnifying glass is arranged in each box to increase the accuracy of field observation.

[0063] The measuring range of the above-mentioned measuring tube assembly is large, and when 1mm scale interval is taken as the minimum value for field observation, the measurable range is 0.90g / cm 3 ~2.35g / cm 3 When the drilling fluid density is 2.35g / cm 3 , the draft depth of the main measuring tube 11 is 20.3Cm, and the counting scale interval is 1mm, and theoretically the value can be observed by naked eye in the field.

[0064] The slow descending mechanism 20 includes a support 21, a support rod 22, a gear 23, a guide cylinder 24, a scraping block 25, a push plate 26 and a spring member 27. The support rod 22 is vertically arranged and slidably penetrates the support 21, one side of the support rod 22 is embedded with a gear rack 221, a supporting table 30 is arranged at the bottom of the support rod 22, the gear 23 is located on the inner side of the support 21 and is engaged with the gear rack 221, and the gear 23 is connected with a knob 231 rotatably arranged on the support 21, the guide cylinder 24 is arranged on the support 21, and the inner side of the guide cylinder 24 has a plurality of rolling balls 241 and a first guide groove 242, the rolling balls 241 are located above the first guide groove 242, the main measuring tube 11 penetrates the inner side of the guide cylinder 24 and is in contact with the rolling balls 241, the first guide groove 242 is arranged in two or more and around the main measuring tube 11, and each first guide groove 242 is inclined to the main measuring tube 11. Each first guide groove 242 is slidably provided with a scraping block 25, and the inner side of the scraping block 25 is provided with an arc-shaped rubber scraping strip 251. The push plate 26 is slidably sleeved on the support rod 22 and extends below the scraping block 25, the spring member 27 is sleeved on the support rod 22, the spring member 27 is located between the push plate 26 and the supporting table 30, and the spring member 27 is connected with the push plate 26 and the supporting table 30 respectively. The support rod 22 has a mark position 222, when the bottom of the main measuring tube 11 abuts against the supporting table 30, the mark position 222 is flush with the top edge of the plug 13.

[0065] Specifically, the rolling balls 241 are arranged in multiple and divided into two guide groups arranged in an up-down manner, each guide group has at least three rolling balls 241 arranged around the main measuring tube 11. The rolling balls 241 are guided by contacting the main measuring tube 11, the rolling balls 241 can roll relative to the guide cylinder 24, and they are in point contact with the main measuring tube 11, which can reduce the moving resistance of the main measuring tube 11 and improve the measuring accuracy.

[0066] The second guide groove 211 is provided with a limiting piece 28, the limiting piece 28 can slide in the second guide groove 211 and is inserted into the rack 221, so as to limit the movement of the support rod 22.

[0067] Further, the first end of the second guide groove 211 away from the support rod 22 is provided with a first magnetic block 41, the side of the limiting piece 28 away from the support rod 22 is provided with a second magnetic block 42 opposite to the first magnetic block 41, the second guide groove 211 is provided with a third magnetic block 43, the magnetic pole directions of the first magnetic block 41 and the second magnetic block 42 are arranged along the second guide groove 211, and the magnetic pole direction of the third magnetic block 43 is inclined to the first magnetic block 41. When the support rod 22 needs to be locked, the limiting piece 28 is pushed to slide and is inserted into the rack 221, at this time, the third magnetic block 43 is located between the first magnetic block 41 and the second magnetic block 42, and the second magnetic block 42 and the third magnetic block 43 can repel each other, so as to position the limiting piece 28 and avoid the unlocking of the support rod 22 caused by the sliding of the limiting piece 28; when the support rod 22 needs to be moved, the limiting piece 28 is pushed to slide and is separated from the rack 221, when the second magnetic block 42 is located between the first magnetic block 41 and the third magnetic block 43, the second magnetic block 42 and the first magnetic block 41 can attract each other, so as to position the limiting piece 28 and avoid the locking of the support rod 22 caused by the sliding of the limiting piece 28.

[0068] Specifically, the second guide groove 211 is provided as an inverted T-shaped groove, the limiting piece 28 is slidably fitted in the upper part of the second guide groove 211, the bottom of the limiting piece 28 extends to the bottom inner cavity of the second guide groove 211, and the width of the bottom inner cavity of the second guide groove 211 is greater than the width of the bottom of the limiting piece 28, that is, there is a spacing between the bottom side wall of the limiting piece 28 and the bottom side wall of the second guide groove 211, and the third magnetic block 43 is installed on the bottom side wall of the second guide groove 211.

[0069] In the present application, the clamp 50 is arranged at the bottom of the support 21, so as to clamp and position the support 21 on the sidewall of the mud pit.

[0070] In addition, other components (such as a flange plate, a first base provided with a counterweight or a second base provided with an electromagnet) can also be arranged according to the structure of the mud pit to replace the clamp 50 and install the support 21 on the mud pit.

[0071] The present application provides a drilling fluid density measuring method based on the drilling fluid density measuring device, and the method comprises the following steps:

[0072] S1, detection preparation: assemble the measuring device, and install the support 21 on the mud pool containing drilling fluid, adjust the support rod 22 and the main measuring tube 11, so that the bottom of the main measuring tube 11 abuts against the supporting table 30, the mark position 222 is flush with the top edge of the plug 13, and the push plate 26 does not contact the scraping block 25, the bottom of the main measuring tube 11 stays at the first standby position higher than the liquid level, and the limiting piece 28 is arranged at a position spaced from the rack 221; the state of the measuring device is as shown in Figure 3 ;

[0073] S2, lower the support rod 22: rotate the knob 231 forward, drive the support rod 22 to move downward through the meshing transmission of the gear 23 and the rack 221, and control the downward movement speed of the support rod 22 to be not more than 5 mm / s after the supporting table 30 contacts the liquid level of the drilling fluid;

[0074] S3, detection reading: after the mark position 222 starts to be lower than the top edge of the plug 13, continue to lower the support rod 22 so that the height difference between the top edge of the plug and the mark position is at least 20 mm, wait for the main measuring tube 11 to be stable, as shown in Figure 4 , then observe the position of the liquid level in the scale structure and read the scale structure;

[0075] S4, dynamic observation: every interval of a set time, observe the position of the liquid level in the scale structure and read the scale structure;

[0076] S5, upward movement and cleaning: rotate the knob 231 reversely, drive the support rod 22 to move upward through the meshing transmission of the gear 23 and the rack 221, and then move the supporting table 30 and the main measuring tube 11 upward, the push plate 26 first contacts the scraping block 25 and pushes the scraping block 25 upward, and the rubber scraping strip 251 is attached to the outer side wall of the main measuring tube 11, as shown in Figure 5 ; continue to move the bottom of the main measuring tube 11 to the second standby position, rotate the knob 231 forward, and stop rotating the knob 231 when the supporting table 30 is out of contact with the bottom of the main measuring tube 11, as shown in Figure 6 ; push the limiting piece 28 to be inserted into the rack 221, and manually wipe the liquid below the part of the main measuring tube 11 below the rubber scraping strip 251 and the liquid at the bottom of the rubber scraping strip 251;

[0077] Wherein, the second standby position is higher than the first standby position, at the first standby position, the spring piece 27 is in a natural stretching state, the scraping block 25 moves downward along the first guide groove 242 under the action of its own gravity, and the rubber scraping strip 251 is arranged in a spaced manner with the main measuring tube 11; at the second standby position and when the knob 231 is stopped rotating after the supporting table 30 is out of contact with the bottom of the main measuring tube 11, the spring piece 27 is in a compressed state, the scraping block 25 moves upward along the first guide groove 242 under the pushing action of the push plate 26, the rubber scraping strip 251 is in close contact with the main measuring tube 11, and the main measuring tube 11 is kept positioned by using the friction force provided by the rubber scraping strip 251.

[0078] In S5, the push plate 26 contacts the scraper 25 and pushes the scraper 25 to move upwards, each rubber scraper 251 is tightly attached to the main measuring tube 11 and forms a ring, at this time the position of the ring is higher than the part of the main measuring tube 11 that is in contact with the liquid, when the support table 30 and the main measuring tube 11 continue to move upwards, the ring scrapes the liquid adhered to the main measuring tube 11; when the main measuring tube 11 reaches the second standby position, the knob 231 is rotated in the positive direction to make the support table 30 move downwards, at this time the spring member 27 is still in the compressed state and the rubber scraper 251 is still tightly attached to the main measuring tube 11, so the main measuring tube 11 will not move downwards with the support table 30, thereby the main measuring tube 11 can be kept at the second standby position and the support table 30 can be separated from the bottom of the main measuring tube 11.

[0079] In S4, a shorter setting time (for example, 2 min) can be preset, and the data can be read and recorded every setting time, so that the dynamic density data of the drilling fluid can be obtained. In addition, in S4, if H increases due to the decrease of the density of the drilling fluid, the part of the main measuring tube 11 above the liquid surface will not adhere to the drilling fluid, and the step can be repeated until the measurement is completed, and then S5 is entered; if H decreases due to the increase of the density of the drilling fluid, the part of the main measuring tube 11 above the liquid surface will adhere to the drilling fluid, and if the adhered drilling fluid affects the reading, S5 can be entered, and after the drilling fluid on the main measuring tube 11 and the drilling fluid at the bottom of the rubber scraper are cleaned, the step S2 is returned.

[0080] After the measurement is completed, S5 is entered, and after the step is completed, the measuring device can be stored or kept in this state, waiting for the next time when the density of the drilling fluid is needed to directly enter S2.

[0081] In some embodiments, for the slow descent mechanism 20, a fourth magnetic block can also be arranged at the top of the first guide groove 242, and a fifth magnetic block is arranged on the scraper 25, the fourth magnetic block and the fifth magnetic block repel each other to ensure that the scraper 25 can move downwards smoothly after the push plate 26 is separated from the scraper 25.

[0082] In addition, for the slow descent mechanism 20, a motor can also be arranged on the support 21 instead of the knob 231.

[0083] The embodiments of the application are described in detail above with reference to the drawings, but the application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the application.

Claims

1. A drilling fluid density measuring device, characterized by, The device comprises: a measuring tube assembly, including a main measuring tube, a counterweight column and a plug, the main measuring tube has a receiving cavity in a columnar shape with an open top, the counterweight column is slidably arranged at the bottom of the receiving cavity, and the plug is arranged at the top of the main measuring tube and inserted into the receiving cavity, and the outer wall of the main measuring tube has a scale structure; a slow descent mechanism connected with a support table and capable of driving the support table to move up and down, the main measuring tube is arranged in the slow descent mechanism, and the bottom of the main measuring tube abuts against the support table; when the main measuring tube and the support table are inserted into the drilling fluid and move downward, the main measuring tube is driven to move upward relative to the support table by buoyancy so as to separate the main measuring tube from the support table; the slow descent mechanism comprises: a support; a support rod arranged vertically and slidably arranged in the support, one side of the support rod is embedded with a rack, and the support table is arranged at the bottom of the support rod; a gear arranged inside the support and engaged with the rack, and the gear is connected with a knob rotatably arranged in the support; a guide cylinder arranged in the support and having a plurality of balls and a first guide groove inside, the balls are arranged above the first guide groove, the main measuring tube is arranged inside the guide cylinder and in contact with the balls, and the first guide groove is arranged in two or more than two and around the main measuring tube and is inclined to the main measuring tube; a scraping block, each first guide groove is slidably arranged with the scraping block, and the inner side of the scraping block is arranged with an arc-shaped rubber scraping strip; a push plate slidably arranged on the support rod and extending below the scraping block; a spring member arranged on the support rod and connected between the push plate and the support table; the support rod is provided with a mark position, and when the bottom of the main measuring tube abuts against the support table, the mark position is flush with the top edge of the plug.

2. A drilling fluid density measuring device according to claim 1, wherein, the bottom of the main measuring tube is arranged in a semispherical shape.

3. The drilling fluid density measurement apparatus of claim 1, wherein, the main measuring tube is arranged in a material of acrylic, and the counterweight column is arranged in a material of stainless steel.

4. The drilling fluid density measurement apparatus of claim 1, wherein, the scale structure comprises a first scale and a second scale, the first scale is used for indicating the density of the drilling fluid, and the second scale is used for indicating the length of the main measuring tube exposed to air or the draught of the main measuring tube in the drilling fluid.

5. The drilling fluid density measurement apparatus of claim 1, wherein, the balls are arranged in a plurality of and divided into two guide groups arranged in an up-down manner, each guide group has at least three balls arranged around the main measuring tube.

6. A drilling fluid density measuring device according to claim 5, wherein, a second guide groove perpendicular to the support rod is arranged on the support, a limiting member is arranged in the second guide groove, and the limiting member is slidably arranged in the second guide groove and inserted into the rack.

7. A drilling fluid density measuring device according to claim 6, wherein, one end of the second guide groove away from the support rod is provided with a first magnetic block, one side of the limiting member away from the support rod is provided with a second magnetic block arranged opposite to the first magnetic block, a third magnetic block is arranged in the second guide groove, the magnetic pole directions of the first magnetic block and the second magnetic block are arranged along the second guide groove, and the magnetic pole direction of the third magnetic block is inclined to the first magnetic block. when the limiting member is slidably arranged so that the third magnetic block is located between the first magnetic block and the second magnetic block, the second magnetic block and the third magnetic block can repel each other; and when the limiting member is slidably arranged so that the second magnetic block is located between the first magnetic block and the third magnetic block, the second magnetic block and the first magnetic block can attract each other.

8. A method of measuring the density of a drilling fluid, characterized by, the drilling fluid density measuring device according to claim 7, and comprising the following steps: S1, detection preparation: the measuring device is assembled, and the support is installed in the mud pool containing drilling fluid, the support rod and the main measuring tube are adjusted, so that the bottom of the main measuring tube abuts against the supporting table, the mark position is flush with the top edge of the plug, the push plate does not contact the scraping block, the bottom of the main measuring tube stays at the first standby position higher than the liquid level; S2, the support rod is lowered: the knob is turned forward, the support rod is driven to move downward through the meshing transmission of the gear and the rack, after the supporting table contacts the liquid level of the drilling fluid, the downward speed of the support rod is controlled to be not more than 5mm / s; S3, detection reading: after the mark position starts to be lower than the top edge of the plug, the support rod is continuously lowered to make the height difference between the top edge of the plug and the mark position at least 20mm, after the main measuring tube is stable, the position of the liquid level in the scale structure is observed, and the scale structure is read; S4, dynamic observation: every interval of a set time, the position of the liquid level in the scale structure is observed, and the scale structure is read; S5, upward cleaning: the knob is turned in reverse, the supporting table and the main measuring tube are moved upward, the push plate first contacts the scraping block and pushes the scraping block upward, the rubber scraping strip is attached to the outer side wall of the main measuring tube, the bottom of the main measuring tube is moved to the second standby position, the knob is turned forward, and the rotation of the knob is stopped when the supporting table and the bottom of the main measuring tube are out of contact, the limiting piece is moved to be inserted into the rack, and the liquid on the part of the main measuring tube below the rubber scraping strip and the liquid at the bottom of the rubber scraping strip are wiped off; Wherein, the second standby position is higher than the first standby position; In S5, when the rotation of the knob is stopped after the supporting table and the bottom of the main measuring tube are out of contact, the spring piece is in a compressed state.

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