Non-conductive slurry performance adjusting short section, well logging device and method

Abstract

The invention provides a non-conductive slurry performance adjusting short section, a well logging device and a well logging method, and belongs to the technical field of reservoir well logging collection. The adjusting short section comprises a storage bin used for storing a conductive additive, a first short section body, a premixing module, a releasing module, a conductive performance monitoring assembly and the like. Based on the technical thought that a conductive additive is mixed into non-conductive slurry (such as oil-based slurry), the conductive additive and the non-conductive slurry in a shaft are premixed in the premixing module to form premixed slurry, and the premixed slurry is pumped out of the first short section body and then mixed with the slurry in the shaft to form mixed slurry with improved conductivity; and the real-time resistivity of the mixed slurry is monitored through the conductivity monitoring component, so that the conductivity of the mixed slurry meets the requirements of a resistivity logging instrument, and high-quality acquisition of resistivity logging information in an oil-based drilling fluid environment is further realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of reservoir logging acquisition, especially reservoir logging acquisition in the environment of oil-based drilling fluid, and particularly relates to a non-conductive mud property adjustment sub-section, a logging device and a method. Background Art

[0002] Oil-based drilling fluid refers to a drilling fluid with oil as the continuous phase. Compared with water-based drilling fluid, oil-based drilling fluid has many advantages such as high temperature resistance, salt and calcium invasion resistance, beneficial to wellbore stability, good lubricity and less damage to oil and gas layers. At present, it has become an important means for drilling high-difficulty high-temperature deep wells, large-angle directional wells, horizontal wells and various complex formations, and can also be widely used as a pipe sticking release fluid, a perforating completion fluid, a workover fluid and a displacement fluid, etc. At the same time, oil-based drilling fluid also brings great challenges to logging acquisition, especially for resistivity logging. In order to enable the current to flow out and return to the instrument receiving electrode, logging tools such as dual laterolog and micro-resistivity scanning imaging require at least a certain conductivity of the drilling fluid in the wellbore. In water-based drilling fluid, the filtrate conductivity is usually 10 S / m, while in oil-based drilling fluid, the conductivity is generally 10 μS / m. The current cannot break through the high-resistance oil-based drilling fluid into the formation, resulting in the inability to measure resistivity logging tools such as dual laterolog and micro-resistivity scanning imaging, and making the traditional resistivity logging method ineffective. Therefore, it is necessary to carry out research work on logging tools applicable to high-resistivity oil-based mud.

[0003] To adapt to the oil-based drilling fluid environment, technicians at home and abroad have proposed many solutions in recent years. Among them, the more effective one is the targeted development of induction logging series instruments. For example, the literature named "Research on the Technology of Directional Resistivity Logging While Drilling in Oil-Based Drilling Fluid" carried out the application research on the method of directional resistivity logging while drilling in oil-based drilling fluid. The technical core of this published literature is the combination of capacitive coupling non-contact conductivity measurement technology and inductive coupling principle. On the one hand, the introduction of C4D technology can overcome the influence of the electrical insulation of oil-based drilling fluid and construct an effective AC measurement path. On the other hand, based on the inductive coupling principle, a stable induced voltage can be generated as the excitation source of the AC measurement path. Another example is the patent literature with the application number CN201810825997.2, which discloses a non-conductive mud resistivity imaging measurement device while drilling. The technical core of this published literature is to detect the resistivity of the formation to be analyzed based on the principle of capacitive coupling, mainly including multiple signal transmitting parts, signal measuring parts and control circuits. This device transmits high-frequency electromagnetic wave excitation through inductive coupling through non-conductive mud to the formation, equivalent the non-conductive mud and the formation to a circuit formed by a capacitance and a resistor, and then separate the formation resistivity after detecting the result, so as to achieve accurate resistivity measurement. The provided non-conductive mud resistivity imaging measurement device while drilling can be applied to the detection of formation resistivity under conditions with poor conductivity such as oil-based mud, and it can provide high-definition images of the wellbore for geological steering and later development. However, due to the limitations of the measurement principle of induction logging itself, induction logging series instruments are only applicable to low-resistivity formations. Under high-resistivity formation conditions, the measurement error of the instrument increases sharply, and it is impossible to reflect the true resistivity of the formation.

[0004] In addition, an oil-based mud imaging logging tool has been developed specifically. The oil-based mud imaging logging tool is a new generation of electrical imaging logging tool applicable to non-conductive mud open-hole wells. Through high-resolution array microelectrode scanning, the change in the resistivity of the wellbore formation caused by formation physical property changes such as fractures, pores, and bedding is converted into an image, which can visually display the geological characteristics of the wellbore formation. Through fine processing by software, various geological analysis applications such as sedimentary structure analysis, fracture identification and attitude analysis, reservoir sorting evaluation, and in-situ stress direction judgment can also be carried out. However, compared with water-based mud imaging logging, the current oil-based mud imaging logging still has defects such as low measurement accuracy, strong multi-solutionity in data interpretation, and high measurement cost, and it is difficult to meet the requirements of oil and gas exploration and evaluation.

[0005] To address the above problems, in an environment such as oil-based drilling fluid, improving the conductivity of non-conductive mud is a feasible auxiliary means for resistivity logging. Based on this, a device for assisting in changing the conductivity of non-conductive mud is urgently needed. Summary of the Invention

[0006] The objective of the embodiments of the present invention is to provide a non-conductive mud property adjustment sub, a logging device, and a method, so as to overcome the technical problems such as the inability to measure the resistivity or the low measurement accuracy caused by the non-conductivity of the mud in an oil-based drilling fluid environment.

[0007] To achieve the above objective, a first aspect of the embodiments of the present invention provides a non-conductive mud property adjustment sub, and the adjustment sub includes:

[0008] A first sub body, which is used to be placed in the wellbore;

[0009] A storage bin, which is arranged in the first sub body and is used to store conductive additives;

[0010] A premixing module, which is arranged in the first sub body and is used to premix the conductive additives pumped from the storage bin and the mud pumped from the wellbore to obtain a premixed slurry;

[0011] A release module, which is arranged in the first sub body and is used to pump the premixed slurry into the wellbore;

[0012] A conductivity monitoring component, which is used to measure the resistivity of the mixed slurry obtained after mixing the premixed slurry pumped out by the release module and the mud in the wellbore, obtain the real-time resistivity of the mixed slurry, and adjust the flow rate of the conductive additives pumped into the premixing module, and / or the flow rate of the mud pumped into the premixing module, and / or the pumping flow rate of the premixed slurry according to the resistivity, so that the resistivity of the mixed slurry is within the range required by the resistivity logging instrument.

[0013] Optionally, the conductivity monitoring component includes:

[0014] A first resistivity monitoring module, which is used to monitor the resistivity of the premixed slurry and adjust the flow rates of the conductive additives and the mud pumped into the premixing module according to the resistivity, so that the resistivity of the premixed slurry is within a first preset range;

[0015] A second resistivity monitoring module, which is used to measure the resistivity of the mixed slurry obtained after mixing the premixed slurry pumped out by the release module and the mud in the wellbore, and obtain the real-time resistivity of the mixed slurry;

[0016] A flow rate control module, which is used to control the pumping flow rate of the premixed slurry and change the pumping flow rate of the premixed slurry according to the real-time resistivity of the mixed slurry, so that the resistivity of the mixed slurry is within the range required by the resistivity logging instrument.

[0017] Optionally, the adjustment sub further includes a wellbore mixing module, and the wellbore mixing module is used to uniformly mix the premixed slurry pumped out by the release module and the mud in the wellbore.

[0018] Optionally, the wellbore mixing module adopts one or more of a turbine mixing method, a vortex mixing method, and an ultrasonic mixing method.

[0019] Optionally, when the mud in the wellbore is oil-based mud, the material type of the conductive additive includes one or more of a liquid-phase conductive fluid, conductive fibers, and a surfactant.

[0020] Optionally, the liquid-phase conductive fluid is an electrolytic salt fluid, and the electrolytic salt fluid is a miscible combination of an oily fluid, a water-soluble alcohol, and an electrolytic salt. The oily fluid is an oil-soluble ethylene glycol or a mixture composed of an oil-soluble ethylene glycol, a mineral oil, a vegetable oil, and a synthetic oil. The water-soluble alcohol is a water-soluble ethylene glycol or an ethylene glycol ether. The electrolytic salt is an inorganic salt or an organic salt.

[0021] Optionally, the surfactant is a mixture of a polar base oil and a complementary fatty acid surfactant.

[0022] Optionally, the premixing module includes a plurality of premixing units arranged in cascade. The premixing unit at the first stage premixes the conductive additive pumped from the storage bin and the mud pumped from the wellbore to obtain a premixed slurry. The premixing units at other stages all pump the premixed slurry from the upper-stage premixing unit connected to themselves, and premix the premixed slurry and the mud pumped from the wellbore. The release module is used to pump the premixed slurry generated by the last-stage premixing unit out to the wellbore;

[0023] The first resistivity monitoring module includes a plurality of first resistivity monitoring units;

[0024] Each premixing unit corresponds to each first resistivity monitoring unit one by one;

[0025] The first resistivity monitoring unit corresponding to the first-stage premixing unit is used to monitor the resistivity of the premixed slurry in the first-stage premixing unit, and adjust the flow rates of the conductive additive and the mud pumped into this premixing unit according to this resistivity, so that the resistivity of the premixed slurry in this premixing unit is within a first preset range;

[0026] The first resistivity monitoring units corresponding to the premixing units at other stages are used to monitor the resistivity of the premixed slurry in the corresponding premixing units, and adjust the flow rates of the premixed slurry and the mud pumped into this premixing unit according to this resistivity, so that the resistivity of the premixed slurry in this premixing unit is within a first preset range.

[0027] Optionally, the mud in the wellbore is pumped into the premixing module after passing through the filter holes opened on the body of the first short joint.

[0028] Optionally, the release module pumps the premixed slurry out to the wellbore through a release hole, and the release hole is opened along the circumferential direction of the body of the first short joint.

[0029] Optionally, the flow rate control module includes a plurality of flow rate control units, and each flow rate control unit is used to adjust the flow rate of the premixed slurry pumped out of each release hole one by one.

[0030] Optionally, the second resistivity monitoring module includes a plurality of first electrodes, each of which is disposed at a different azimuth in the wellbore. The different azimuths are circumferential azimuths concentric with the central axis of the first short joint body. Each first electrode is used to measure the resistivity of the mixed mud at its corresponding azimuth. The corresponding flow rate control unit adjusts the flow rate of the premixed mud pumped out from the release hole at the same azimuth as the first electrode according to the resistivity measured by the first electrode. The corresponding flow rate control unit is the flow rate control unit corresponding to the release hole at the same azimuth as the first electrode.

[0031] In a second aspect of the embodiments of the present invention, a logging device is provided. The logging device includes a non-conductive mud property adjusting short joint and a resistivity logging instrument according to the first aspect of the embodiments of the present invention. The non-conductive mud property adjusting short joint is connected to the resistivity logging short joint in the resistivity logging instrument.

[0032] During upward logging, the non-conductive mud property adjusting short joint and the resistivity logging short joint are placed in the wellbore, and the non-conductive mud property adjusting short joint is connected above the resistivity logging short joint.

[0033] During downward logging, the non-conductive mud property adjusting short joint and the resistivity logging short joint are placed in the wellbore, and the non-conductive mud property adjusting short joint is connected below the resistivity logging short joint.

[0034] In a third aspect of the embodiments of the present invention, a logging method is provided. The method includes the following implementation steps:

[0035] S100. Combine and connect the non-conductive mud property adjusting short joint and the resistivity logging short joint, and then lower them into the wellbore.

[0036] S200. Start the non-conductive mud property adjusting short joint and the resistivity logging short joint. The preset mode of the resistivity measurement short joint is the measurement mode.

[0037] S300. The non-conductive mud property adjusting short joint and the resistivity logging short joint perform logging movement at a predetermined speed. Every time a target measurement point is reached, the non-conductive mud property adjusting short joint releases premixed mud, and the premixed mud is mixed with the mud in the wellbore, so that the conductivity of the mud in the wellbore changes.

[0038] S400. When the resistivity of the mixed mud meets the required range of the resistivity logging short joint, the resistivity logging short joint performs formation parameter measurement at this target measurement point.

[0039] The above technical solution is based on the technical idea of mixing conductive additives into non-conductive mud (such as oil-based mud, etc.). By premixing the conductive additives with the non-conductive mud in the wellbore in a premixing module to form a premixed slurry, the premixed slurry is pumped out of the first short joint body and then mixed with the mud in the wellbore to form a mixed slurry with improved conductivity. The real-time resistivity of the mixed slurry is monitored by a conductivity monitoring component, so that the conductivity of the mixed slurry meets the requirements of the resistivity logging instrument.

[0040] By improving the conductivity of the mud in the wellbore, resistivity logging instruments such as dual laterolog and micro-resistivity scanning imaging can carry out resistivity logging normally in an environment such as oil-based drilling fluid, so as to realize the high-quality acquisition of resistivity logging data in a non-conductive mud environment, which is of great significance for reservoir evaluation.

[0041] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. They are used together with the following specific implementation to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0043] Figure 1 It is a schematic structural diagram of a non-conductive mud property adjustment short joint;

[0044] Figure 2 It is a schematic diagram of multi-stage premixing;

[0045] Figure 3 It is a schematic diagram of non-uniform mixing of the premixed slurry and the mud in the wellbore;

[0046] Figure 4 It is a schematic diagram of uniform mixing;

[0047] Figure 5 It is a schematic diagram of a logging device.

[0048] DESCRIPTION OF THE REFERENCE NUMERALS

[0049] In the figure, 1, the first short joint body; 2, the storage bin; 3, the premixing module; 4, the non-conductive mud property adjustment short joint; 5, the release hole; 6, the filtering hole; 7, the wellbore mixing module; 8, the first electrode; 9, the resistivity logging short joint; 10, the logging device; 11, the premixed slurry; 12, the non-uniform mixed slurry; 13, the uniform mixed slurry; 14, the formation; 15, the wellbore. DETAILED DESCRIPTION OF THE INVENTION

[0050] The following will describe in detail the specific implementation manners of the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only for explaining and interpreting the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0051] Meanwhile, in the following description, for the purpose of explanation, many specific details are set forth to provide a thorough understanding of the embodiments of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without these specific details or in the specific manners described herein.

[0052] While drilling the well, logging while drilling will collect formation information, process data and transmit the data to the surface in real time or near real time, thereby helping to analyze the downhole formation conditions in a timely manner, adjust the drilling parameters, optimize the drilling operation, and further enabling the geological steering drilling to achieve the maximum reservoir encounter rate, and increasing the production by greatly increasing the contact area between the wellbore and the formation.

[0053] During the drilling process, drilling fluid (mud) is used. The main functions of the drilling fluid (mud) mainly include:

[0054] (1) Cooling the drill bit;

[0055] (2) Keeping the pressure in the well slightly greater than the formation pressure to prevent blowout;

[0056] (3) Bringing the rock debris crushed by the drill bit back to the surface through the space between the drill string and the formation, etc.

[0057] According to conductivity, the commonly used muds at the present stage can be divided into two types: water-based mud and oil-based mud. Under certain conditions, especially in unconventional shale gas reservoirs, since the main formation of the shale gas layer is mudstone, and the clay substances in the mudstone are sensitive to water (swell when encountering water), if water-based mud is used, it will cause changes in the wellbore size, and further pose a threat to drilling safety. Therefore, for shale gas reservoirs, oil-based mud must be used for drilling operations.

[0058] Embodiment 1

[0059] The present invention provides a non-conductive mud property adjusting sub-section 4 for adjusting the resistivity of the non-conductive mud in the wellbore 15 during resistivity logging, and the non-conductive mud is oil-based mud, etc.

[0060] Specifically referring to Figures 1-4 , the non-conductive mud property adjusting sub-section 4 includes a first sub-section body 1. When assisting the resistivity logging instrument to log, the first sub-section body 1 will be combined and connected with the resistivity logging sub-section 9 and placed in the wellbore 15. For example, Figures 4-5 as shown, the first sub-section body 1 and the resistivity logging sub-section 9 are sleeved on the same support shaft.

[0061] A storage bin 2, a premixing module 3, and a release module are provided inside the first short section body 1.

[0062] The storage bin 2 is used to store conductive additives.

[0063] The premixing module 3 is used to premix the conductive additives pumped from the storage bin 2 and the mud pumped from the wellbore 15 to obtain a premixed slurry 11. Preferably, the mud can enter the premixing module 3 through the filter holes 6 opened on the first short section body 1, and the filter holes 6 filter out rock debris while pumping in the mud.

[0064] The release module is used to pump the premixed slurry 11 out to the wellbore 15. Specifically, a motor can drive a lead screw to push the premixed slurry 11 into the high-pressure wellbore 15. Preferably, the premixed slurry 11 can be pumped out through the release holes 5 opened on the first short section body 1.

[0065] The non-conductive mud property adjustment short section 4 further includes a conductivity monitoring component. The conductivity monitoring component is used to measure the resistivity of the mixed slurry obtained after the premixed slurry 11 pumped out by the release module is mixed with the mud in the wellbore 15, obtain the real-time resistivity of the mixed slurry, and adjust the flow rate of the conductive additives pumped into the premixing module 3, and / or the flow rate of the mud pumped into the premixing module 3, and / or the pumping flow rate of the premixed slurry 11 according to the resistivity, so that the resistivity of the mixed slurry is within the range required by the resistivity logging instrument, that is, the conduction of the current by the mud enables the electrode of the resistivity logging instrument to output current to reach the formation 14 smoothly through the mud.

[0066] To enable the conductivity of the non-conductive mud to be improved after adding conductive additives, in oil and gas exploitation, it is known to those skilled in the art what specific materials or material miscibility are used to obtain the conductive additives.

[0067] Exemplarily, in one embodiment, the conductivity monitoring component is composed of a first resistivity monitoring module, a second resistivity monitoring module, and a flow rate control module.

[0068] Among them, the first resistivity monitoring module is connected to the premixing module 3 and is used to monitor the resistivity of the premixed slurry 11, and adjust the flow rates of the conductive additives and the mud pumped into the premixing module 3 according to the resistivity, so that the resistivity of the premixed slurry 11 is within a first preset range. It is known that the first preset range can be determined according to the specific type of conductive additives selected, the volume of the mud in the wellbore 15, the addition amount of the conductive additives, the dilution multiple set by the premixing module 3, etc. Here, the connection means that: for example, when the first resistivity monitoring module uses electrodes to measure the resistivity of the fluid, the electrodes are in contact with the premixed slurry 11 in the premixing module 3.

[0069] The second resistivity monitoring module is used to measure the resistivity of the mixed mud obtained by mixing the premixed mud 11 pumped out by the release module and the mud in the wellbore 15, so as to obtain the real-time resistivity of the mixed mud. After the premixed mud 11 is pumped out of the release module to the first short joint body 1, it will be mixed with the mud in the wellbore 15. The second resistivity monitoring module can select electrodes to measure the resistivity of the mixed mud at this time, and the electrodes are in contact with the mixed mud in the wellbore 15.

[0070] The flow rate regulation module is connected to the release module and is used to control the pumping flow rate of the premixed mud 11, and change the pumping flow rate of the premixed mud 11 according to the real-time resistivity of the mixed mud measured by the second resistivity monitoring module, so that the resistivity of the mixed mud is within the range required by the resistivity logging instrument. Here, the connection means that, for example, the flow rate regulation module selects an electric control valve body and changes the flow rate of the premixed mud 11 flowing through the electric control valve body according to the real-time resistivity of the mixed mud.

[0071] After controlling the resistivity of the premixed mud 11 within the first preset range through the first resistivity monitoring module, and then monitoring the resistivity of the finally formed mixed mud through the second resistivity monitoring module, this kind of step-by-step monitoring compared with single-stage monitoring lays a foundation for the refined regulation of the electrical conductivity of the mud in the wellbore 15, and can also avoid changing the pumping flow rate of the premixed mud 11 multiple times, with stronger timeliness, and thus can improve the resistivity logging efficiency.

[0072] Exemplarily, in one embodiment, the non-conductive mud property adjustment short joint 4 further includes a wellbore mixing module 7, and the wellbore mixing module 7 evenly mixes the premixed mud 11 pumped out by the release module and the mud in the wellbore 15. The wellbore mixing module 7 can be sleeved or hung on the outer wall of the first short joint body 1.

[0073] Optionally, the wellbore mixing module 7 can adopt one or more of the turbine mixing method, the vortex mixing method and the ultrasonic mixing method. Among them, the turbine mixing method stirs through the turbine blades to make the premixed mud 11 and the mud in the wellbore 15 fully and evenly mixed; the vortex mixing method uses eccentric rotation to generate a vortex in the mud in the wellbore 15, so that the premixed mud 11 and the mud in the wellbore 15 are fully and evenly mixed; the ultrasonic mixing method generates radial vibration in the wellbore 15 through the transducer, so that the premixed mud 11 and the mud in the wellbore 15 are fully and evenly mixed.

[0074] When the wellbore mixing module 7 is not provided, the highly conductive premixed mud 11 pumped out by the release hole 5 is in a non-uniform mixing state with the mud in the wellbore 15 (that is: forming non-uniform mixed mud 12), and at this time, the electrical uniformity of the mud is poor. After the wellbore mixing module 7 is provided, the mud in the wellbore 15 and the premixed mud 11 pumped out by the release hole 5 are quickly mixed, and the mixed mud shows electrical uniformity (that is: forming uniform mixed mud 13). At this time, the current output by the resistivity logging short joint 9 enters the formation 14 after passing through the uniform mixed mud 13. For details, please refer toFigures 3-4 In Figure 4 the wellbore mixing module 7 is hung on the outer wall of the first short joint body 1.

[0075] Exemplarily, in an oil-based drilling fluid environment, the conductive additive stored in the storage bin 2 can be selected from one or more of a liquid-phase conductive fluid, conductive fibers, and surfactants.

[0076] For example, the liquid-phase conductive fluid can be an electrolytic salt or brine. The electrolytic salt can be a miscible combination of an oily fluid, a water-soluble alcohol, and an electrolytic salt. To make the resistivity of the mixed mud within the range required by the resistivity logging tool, the concentration of the electrolytic salt or brine can be reasonably selected. The oily fluid can preferably be an oil-soluble ethylene glycol or a mixture composed of mineral oil, vegetable oil, and synthetic oil. The water-soluble alcohol can preferably be a water-soluble ethylene glycol or ethylene glycol ether, such as ethylene glycol, diethylene glycol, propylene glycol, etc. The electrolytic salt or brine can be an inorganic salt or an organic salt, such as sodium chloride, sodium bromide, potassium chloride, ammonium chloride, magnesium chloride, calcium chloride, etc.

[0077] The conductive fibers can be carbon nanotubes, etc.

[0078] The surfactant can be a mixture or combination of a polar base oil and a complementary fatty acid surfactant, such that the polar base oil and the surfactant contain the oil layer of an inverse emulsion. The surfactant forms micelles and is arranged alternately in the barrier layer of the oil-based drilling fluid, and the density is higher than that of any surfactant formed alone, so that the mixed mud has sufficient conductivity.

[0079] When the conductive additive is selected from one or more of a liquid-phase conductive fluid, conductive fibers, and surfactants, the conductive additive has high performance, can realize the instant conductivity of non-conductive mud in an oil-based drilling fluid environment, quickly meet the conductivity requirement of the resistivity logging tool for the conductive fluid, and further can realize fast logging in this environment.

[0080] When the conductive additive is selected from one or more of a liquid-phase conductive fluid, conductive fibers, and surfactants, the conductive additive has high performance. At this time, according to the volume of the oil-based mud in the wellbore 15, the addition amount of the conductive additive is determined. The addition ratio is generally less than 1:1000, that is: in every 1 L of oil-based mud, the addition amount of the conductive additive is less than 1 mL, which can meet the requirement of the resistivity logging tool for the conductive performance of the mud. It can be seen that when this type of conductive additive is applied, it needs to be precisely released in a small volume through the release module.

[0081] Therefore, in one embodiment, a multi-stage premixing and release method is further proposed. Correspondingly, the premixing module 3 is further improved.

[0082] Specifically, as Figure 2As shown, the premixing module 3 includes a plurality of premixing units arranged in cascade, such as the first-stage premixing unit to the Nth-stage premixing unit shown in the figure. The number of premixing units can be reasonably allocated according to the dilution ratio. The premixing unit at the first stage premixes the conductive additive pumped from the storage bin 2 and the mud pumped from the wellbore to obtain the premixed slurry 11. The premixing units at other stages all pump in the premixed slurry 11 from the upper-stage premixing unit connected to themselves, and premix the premixed slurry 11 and the mud pumped from the wellbore 15. The release module is used to pump out the premixed slurry 11 generated by the last-stage premixing unit to the wellbore 15.

[0083] Correspondingly, at this time, the first resistivity monitoring module is composed of a plurality of first resistivity monitoring units. The number of first resistivity monitoring units is the same as the number of premixing units, and each stage of premixing unit corresponds to each first resistivity monitoring unit one by one.

[0084] The first resistivity monitoring unit corresponding to the first-stage premixing unit is used to monitor the resistivity of the premixed slurry 11 in the first-stage premixing unit, and adjust the flow rates of the conductive additive and the mud pumped into this premixing unit according to this resistivity, so that the resistivity of the premixed slurry 11 in this premixing unit is within the first preset range.

[0085] The first resistivity monitoring units corresponding to the premixing units at other stages are used to monitor the resistivity of the premixed slurry 11 in the corresponding premixing units, and adjust the flow rates of the premixed slurry 11 and the mud pumped into this premixing unit according to this resistivity, so that the resistivity of the premixed slurry 11 in this premixing unit is within the first preset range.

[0086] The adoption of the above multi-stage premixing and release method brings the following advantages:

[0087] 1) Precise dilution of the conductive additive is achieved through multi-stage premixing, effectively reducing the requirement for the precision control of the release amount of the conductive additive;

[0088] 2) Monitoring the resistivity of the premixed slurry 11 by each first resistivity monitoring unit lays a foundation for the refined regulation of the conductive performance of the mud in the wellbore 15;

[0089] 3) Through multi-stage premixing, the conductive performance of the premixed slurry 11 is greatly reduced compared with the conductive performance of the original conductive additive, laying a foundation for the rapid mixing of the mud in the subsequent wellbore 15;

[0090] 4) Enables the conductivity of the mud in the wellbore 15 to quickly meet the requirements of the resistivity logging for the current-conducting fluid, further enhancing the instant conductive effect.

[0091] Exemplarily, in one embodiment, the release holes 5 are arranged along the circumferential direction of the first short joint body 1, that is, the release holes 5 are arranged in a 360° circumferential arrangement. The 360° circumferential arrangement is more conducive to the rapid mixing of the mud in the subsequent wellbore 15.

[0092] Exemplarily, in one embodiment, the flow rate regulation module includes a plurality of flow rate regulation units, and each flow rate regulation unit is used to regulate the flow rate of the premixed slurry 11 pumped out of each discharge hole 5 in a one-to-one correspondence.

[0093] Exemplarily, in one embodiment, in order to achieve precise control of the flow rate of the premixed slurry 11 discharged from the discharge holes 5 in all directions, when the second resistivity detection module measures the resistivity of the mixed slurry, multi-directional measurement is adopted.

[0094] Specifically, as shown in Figure 1 After defining the electrodes in the second resistivity detection module as the first electrodes 8, the number of the first electrodes 8 is multiple, and each first electrode 8 is arranged at different positions in the wellbore 15 in a one-to-one correspondence. The different positions are the circumferential positions concentric with the central axis of the first short joint body 1. Each first electrode 8 is used to measure the resistivity of the mixed slurry at its corresponding position. After the first electrode 8 measures the resistivity of the mixed slurry at its corresponding position, the flow rate regulation unit corresponding to the discharge hole 5 at the same position adjusts the flow rate of the premixed slurry 11 pumped out of the discharge hole 5 at the same position. For example: if the resistivity of the mixed slurry at a certain position is too high, it is fed back to the corresponding flow rate regulation unit, and the flow rate regulation unit increases the discharge flow rate of the premixed slurry 11 at the corresponding position, otherwise it reduces the discharge flow rate of the premixed slurry 11 at the corresponding position.

[0095] It should be noted that Figure 1 This is a structural example of the non-conductive mud property adjustment short joint 4 implemented in this embodiment. In the figure, the first electrode 8 is arranged at one end of the first short joint body 1 close to the resistivity logging short joint 9, the filter holes 6 are opened near the other end of the first short joint body 1, the discharge holes 5 are located on the right side of the wellbore mixing module 7, the storage bin 2 is arranged on the left side of the internal space of the first short joint body 1, and the premixing module 3 is arranged on the right side of the internal space of the first short joint body 1.

[0096] For those skilled in the art, it should be understood that in specific applications, the specific setting positions of the various components in the non-conductive mud property adjustment short joint 4 can be set according to actual needs, and the structural connection methods between the various components in the non-conductive mud property adjustment short joint can also be designed accordingly according to actual needs. For example, corresponding support members, connecting members, etc. are designed. The specific structural connection method is not the innovation point of the present invention, so this embodiment does not describe this part of the content in detail.

[0097] Embodiment 2

[0098] Please refer to Figure 5, the present invention also provides a logging device. The logging device 10 includes the non-conductive mud property adjusting sub-section 4 implemented in the first embodiment and a resistivity logging instrument. The non-conductive mud property adjusting sub-section 4 is connected to the resistivity logging sub-section 9 inside the resistivity logging instrument.

[0099] During upward logging, the non-conductive mud property adjusting sub-section 4 and the resistivity logging sub-section 9 are placed in the wellbore 15, and the non-conductive mud property adjusting sub-section 4 is connected above the resistivity logging sub-section 9. Figure 5 It is a schematic diagram of the logging device 10 during upward logging.

[0100] During downward logging, the non-conductive mud property adjusting sub-section 4 and the resistivity logging sub-section 9 are placed in the wellbore 15, and the non-conductive mud property adjusting sub-section 4 is connected below the resistivity logging sub-section 9.

[0101] By using this logging device 10, the conductivity of the non-conductive mud can be adjusted in real time during the logging process, which has the advantages of high convenience, high efficiency of data acquisition, and low cost.

[0102] Embodiment Three

[0103] The present invention also provides a logging method using the aforementioned logging device 10. The method specifically includes the following implementation steps:

[0104] S100. Combine and connect the non-conductive mud property adjusting sub-section 4 and the resistivity logging sub-section 9 and lower them into the wellbore 15.

[0105] S200. Start the non-conductive mud property adjusting sub-section 4 and the resistivity logging sub-section 9. The preset mode of the resistivity measurement sub-section is the measurement mode.

[0106] S300. The non-conductive mud property adjusting sub-section 4 and the resistivity logging sub-section 9 perform logging movement at a predetermined speed. Every time a target measurement point is reached, the non-conductive mud property adjusting sub-section 4 releases the premixed mud 11. The premixed mud 11 is mixed with the mud in the wellbore 15, so that the conductivity of the mud in the wellbore 15 changes.

[0107] S400. When the resistivity of the mixed mud meets the required range of the resistivity logging sub-section 9, the resistivity logging sub-section 9 performs resistivity logging data acquisition at this target measurement point.

[0108] In a non-conductive mud environment such as oil-based mud, resistivity logging instruments such as dual laterolog and micro-resistivity scanning imaging cannot conduct tests normally. During logging operations, a traditional practice is to displace the mud in the entire wellbore, which is costly and has low logging efficiency, making the implementation of logging very inconvenient. The above logging method adjusts the conductivity of the mud in real time during logging, avoiding the above defects of traditional logging operations and achieving high-quality acquisition of resistivity logging data. In addition, compared with induction logging series and oil-based mud imaging logging, the accuracy of the resistivity logging data collected is higher.

[0109] Taking the above logging as an example, a specific implementation process of the above logging method is as follows:

[0110] A01. Device preparation: Conduct performance tests on the measurement device 10 to ensure it can work properly.

[0111] A02. Start the logging device 10 and prepare for logging: Lower the logging device 10 into the well through cable or drill string pushing. The surface acquisition system monitors whether the logging device 10 reaches the target formation for logging according to the depth information. When reaching the target layer, the surface acquisition system starts the logging device 10 and raises the logging device 10 to start logging. From this moment on, the logging device 10 and other downhole instruments start to move upward at a predetermined speed. During the upward movement, the resistivity logging sub-section 9 operates according to the instrument measurement mode.

[0112] A03. Arrive at the first target measurement point, and each premixing unit operates. Pump out the conductive additive from the storage bin 2, and dilute the conductive additive through multi-stage premixing of the multi-stage premixing unit. For example, dilute the conductive additive by 20 to 100 times. Then, through the release hole 5, under the control of the flow rate regulation module, pump out the premixed slurry 11 into the wellbore 15 at a preset flow rate. After the premixed slurry 11 is released, the conductivity distribution of the mud in the wellbore 15 is as Figure 3 shown.

[0113] A04. Through the wellbore mixing module 7, after the premixed slurry 11 is pumped out from the release hole 5, it is uniformly mixed with the mud in the wellbore 15.

[0114] After the premixed slurry 11 pumped out from the premixing bin enters the wellbore 15, it is mainly concentrated near the release hole 5 and cannot be evenly mixed with the mud in the wellbore 15, resulting in poor electrical uniformity of the mud in the wellbore 15 and affecting the quality of resistivity logging. Through the wellbore mixing module 7, by using methods such as turbine, vortex or ultrasonic mixing, the mud and premixed slurry 11 in the wellbore 15 are mixed evenly, ensuring the electrical uniformity of the mud. After mixing, the conductivity distribution of the mud in the wellbore 15 is as Figure 4 shown.

[0115] A05. Monitor and regulate the real-time resistivity of the mixed mud until the conductivity requirement of the current-conducting fluid for the resistivity logging sonde 9 is met.

[0116] A06. The resistivity logging sonde 9 starts to collect the resistivity logging data of the first target measuring point.

[0117] A07. Reach the subsequent target measuring points in sequence and repeat steps A03 - A06 to complete the collection of the resistivity logging data of all target measuring points.

[0118] Based on the above disclosure, those skilled in the art can clearly know the logging process during the downhole logging, and this embodiment will not elaborate on this part of the content.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A non-conductive mud property adjusting sub, characterized in that, The adjusting nipple includes: A first nipple body for being placed in a wellbore; A storage bin provided in the first nipple body and used for storing a conductive additive; A premixing module provided in the first nipple body and used for premixing the conductive additive pumped from the storage bin and the mud pumped from the wellbore to obtain a premixed slurry; A release module provided in the first nipple body and used for pumping the premixed slurry out to the wellbore; A conductive property monitoring component for measuring the resistivity of the mixed slurry obtained after mixing the premixed slurry pumped out by the release module and the mud in the wellbore, obtaining the real-time resistivity of the mixed slurry, and adjusting the flow rate of the conductive additive pumped into the premixing module, and / or the flow rate of the mud pumped into the premixing module, and / or the pumping flow rate of the premixed slurry according to the resistivity, so that the resistivity of the mixed slurry is within the range required by the resistivity logging instrument.

2. The non-conductive mud property adjusting nipple according to claim 1, wherein The conductive property monitoring component includes: A first resistivity monitoring module for monitoring the resistivity of the premixed slurry and adjusting the flow rates of the conductive additive and the mud pumped into the premixing module according to the resistivity, so that the resistivity of the premixed slurry is within a first preset range; A second resistivity monitoring module for measuring the resistivity of the mixed slurry obtained after mixing the premixed slurry pumped out by the release module and the mud in the wellbore, and obtaining the real-time resistivity of the mixed slurry; A flow rate control module for controlling the pumping flow rate of the premixed slurry and changing the pumping flow rate of the premixed slurry according to the real-time resistivity of the mixed slurry, so that the resistivity of the mixed slurry is within the range required by the resistivity logging instrument.

3. A non-conductive mud property adjusting nipple according to claim 1, characterized in that, The adjusting nipple further includes a wellbore mixing module for uniformly mixing the premixed slurry pumped out by the release module and the mud in the wellbore.

4. A non-conductive mud property adjusting nipple according to claim 3, characterized in that, The wellbore mixing module adopts one or more of a turbine mixing method, a vortex mixing method, and an ultrasonic mixing method.

5. The non-conductive mud property adjusting nipple according to claim 2, characterized in that, When the mud in the wellbore is oil-based mud, the material type of the conductive additive includes one or more of a liquid-phase conductive fluid, a conductive fiber, and a surfactant.

6. The non-conductive mud property adjusting nipple according to claim 5, characterized in that, The liquid-phase conductive fluid is an electrolytic salt fluid, and the electrolytic salt fluid is a miscible combination of an oily fluid, a water-soluble alcohol, and an electrolytic salt. The oily fluid is an oil-soluble ethylene glycol or a mixture of an oil-soluble ethylene glycol and a mineral oil, a vegetable oil, or a synthetic oil. The water-soluble alcohol is a water-soluble ethylene glycol or an ethylene glycol ether. The electrolytic salt is an inorganic salt or an organic salt.

7. A non-conductive mud property adjusting nipple according to claim 5, characterized in that, The surfactant is a mixture of a polar base oil and a complementary fatty acid surfactant.

8. The non-conductive mud property adjusting nipple according to claim 2 or 5, characterized in that The premixing module includes a plurality of cascaded premixing units. The premixing unit at the first stage premixes the conductive additive pumped from the storage bin and the mud pumped from the wellbore to obtain a premixed slurry. The premixing units at other stages all pump the premixed slurry from the upper-stage premixing unit connected to themselves, and premix the premixed slurry and the mud pumped from the wellbore. The release module is used for pumping the premixed slurry generated by the last-stage premixing unit out to the wellbore; The first resistivity monitoring module includes a plurality of first resistivity monitoring units; Each stage of premixing unit corresponds to each first resistivity monitoring unit one by one; The first resistivity monitoring unit corresponding to the first-stage premixing unit is used to monitor the resistivity of the premixed slurry in the first-stage premixing unit, and adjust the flow rates of the conductive additive and the slurry pumped into the premixing unit according to the resistivity, so that the resistivity of the premixed slurry in the premixing unit is within the first preset range; The first resistivity monitoring unit corresponding to the premixing units of other stages is used to monitor the resistivity of the premixed slurry in the corresponding premixing unit, and adjust the flow rates of the premixed slurry and the slurry pumped into the premixing unit according to the resistivity, so that the resistivity of the premixed slurry in the premixing unit is within the first preset range.

9. A non-conductive mud property adjusting nipple according to claim 1, characterized in that, The slurry in the wellbore is pumped into the premixing module through the filtering holes opened on the body of the first short section.

10. The non-conductive mud property adjusting nipple according to claim 2, characterized in that, The release module pumps the premixed slurry out of the wellbore through the release holes, and the release holes are opened along the circumferential direction of the body of the first short section.

11. A non-conductive mud property adjusting sub according to claim 10, characterized in that, The flow rate control module includes a plurality of flow rate control units, and each flow rate control unit is used to adjust the flow rate of the premixed slurry pumped out of each release hole one by one.

12. A non-conductive mud property adjusting nipple according to claim 11, characterized in that, The second resistivity monitoring module includes a plurality of first electrodes, and each first electrode is arranged at different azimuths in the wellbore one by one. The different azimuths are circumferential azimuths concentric with the axis of the body of the first short section. Each first electrode is used to measure the resistivity of the mixed slurry at its corresponding azimuth. The corresponding flow rate control unit adjusts the flow rate of the premixed slurry pumped out of the release hole at the same azimuth as the first electrode according to the resistivity measured by the first electrode. The corresponding flow rate control unit is the flow rate control unit corresponding to the release hole at the same azimuth as the first electrode.

13. A logging device, characterized in that, It includes a non-conductive mud property adjustment short section and a resistivity logging instrument according to any one of claims 1-12. The non-conductive mud property adjustment short section is connected to the resistivity logging short section in the resistivity logging instrument; During uphole logging, the non-conductive mud property adjustment short section and the resistivity logging short section are placed in the wellbore, and the non-conductive mud property adjustment short section is connected above the resistivity logging short section; During downhole logging, the non-conductive mud property adjustment short section and the resistivity logging short section are placed in the wellbore, and the non-conductive mud property adjustment short section is connected below the resistivity logging short section.

14. A logging method, characterized in that, It includes: S100. Combine and connect the non-conductive mud property adjustment short section and the resistivity logging short section, and then lower them into the wellbore; S200. Start the non-conductive mud property adjustment short section and the resistivity logging short section. The preset mode of the resistivity measurement short section is the measurement mode; S300. The non-conductive mud property adjustment short section and the resistivity logging short section perform logging movement at a predetermined speed. Every time a target measurement point is reached, the non-conductive mud property adjustment short section releases the premixed slurry, and the premixed slurry is mixed with the slurry in the wellbore, so that the conductivity of the slurry in the wellbore changes; S400. When the resistivity of the mixed slurry meets the required range of the resistivity logging short section, the resistivity logging short section performs the formation parameter measurement at this target measurement point.

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