An adaptive well wall device

Abstract

The present invention relates to the field of petroleum well logging, and in particular to an adaptive well wall sticking device for lithologic density logging, which can be used in horizontal well logging instruments to solve the problem of density instruments sticking to the well wall. The device mainly comprises an upper joint, an upper connector, a density probe, a lower connector, a main body, and a lower joint. The two ends of the main body are respectively connected to the upper joint and the lower joint. The main body is provided with a receiving portion, and the density probe is hinged to the receiving portion through the upper and lower connectors. One end of the lower connector is hinged to the receiving portion through a pin and a pin hole. The pin hole is a long hole that slides with the pin. When the density probe, the upper connector, and the lower connector are connected in a straight line, the overall maximum diameter of the main body, the density probe, the upper connector, and the lower connector is less than or equal to the minimum diameter of the upper and lower connectors. The density probe can be pushed against the well wall without power supply. The device is applicable to horizontal wells, inclined wells, etc., effectively improving the logging accuracy and meeting the requirements of storage logging.

Description

Technical Field

[0001] The present invention relates to the field of petroleum well logging, in particular to an adaptive well wall sticking device for lithologic density logging, which can be applied in horizontal well logging instruments and solves the problem of density instruments sticking to the well wall. Background Art

[0002] Density logging, also known as gamma-ray logging, utilizes Cs-137 as a gamma source, emitting gamma rays with an energy of 0.66 MeV. It is an important logging method for determining lithology and rock density. Combined with sonic logging and neutron logging, it forms a lithologic-porosity logging suite.

[0003] The fluids in production wells primarily include oil, gas, and water, which have significant differences in density. Fluid density measurement involves using a densitometer to measure fluid density, thereby distinguishing the properties of the production fluid profile.

[0004] Instruments for measuring fluid density primarily include differential pressure densitometers and gamma densitometers. Fluid density data obtained from these instruments can be used to qualitatively analyze the type of fluid entering the wellbore, delineate fluid interfaces, and quantitatively determine liquid holdup in two-phase flow.

[0005] When using a logging instrument to perform density logging, in order to make the logging results more accurate, it is usually necessary to make the instrument probe close to the well wall, or close to the mud cake on the well wall, before density logging can be carried out.

[0006] The density probe is usually installed on a density nipple and then transported downhole for density logging.

[0007] The existing density nipple adopts the cable logging method and the motor-pump-hydraulic driven pushing method, which requires a power supply to power a high-power motor to drive the actuator to make the probe close to the well wall, and cannot meet the requirements of storage logging.

[0008] According to the structural design requirements of the ultra-high temperature storage logging system, the adaptive fitting of the density probe and the well wall is achieved.

[0009] Since the storage logging system is battery-powered, the instrument cannot have any form of high-power pushing mechanism, so the density probe cannot be attached to the well wall by relying on a power pushing mechanism.

[0010] The new density push-pull method adopts a power-free and non-active push-pull method, and is designed with a multi-degree-of-freedom linkage mechanism. The probe's own weight is used to separate it from the main body and adapt to the shape of the well wall.

[0011] In order to solve this problem, it is necessary to design a pushing device that can adaptively ensure that the density instrument is reliably close to the well wall.

[0012] Adaptive alignment of the density probe to the wellbore wall is achieved according to the structural design requirements of the ultra-high-temperature storage logging system. Because the storage logging system is battery-powered, it cannot have any high-powered push mechanisms, making it impossible for the density probe to adhere to the wellbore wall.

[0013] The new density push-pull method adopts a power-free and non-active push-pull method, and is designed with a multi-degree-of-freedom linkage mechanism. The probe's own weight is used to separate it from the main body and adapt to the shape of the well wall. Summary of the Invention

[0014] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an adaptive well wall sticking device.

[0015] The technical solution is as follows:

[0016] A self-adaptive well wall-adhering device mainly consists of an upper joint, an upper connector, a density probe, a lower connector, a main body, and a lower joint. The two ends of the main body are respectively connected to the upper joint and the lower joint. The main body is provided with a receiving portion, and the density probe is hinged to the receiving portion through the upper and lower connectors; one end of the lower connector is hinged to the receiving portion through a pin shaft and a pin hole, and the pin hole is a long hole, and the long hole slides with the pin shaft; when the density probe, the upper connector, and the lower connector are connected in a straight line, the overall maximum diameter of the main body, the density probe, the upper connector, and the lower connector is less than or equal to the minimum diameter of the upper and lower joints.

[0017] Furthermore, both the upper and lower joints are sleeved with eccentrics, with the heavier side of the eccentrics facing the main body. The eccentrics are eccentric sleeve structures, with the lighter side having a longitudinal opening. The upper and lower connectors are H-shaped connectors. The accommodating portion is a U-shaped recess, with the opening of the U-shaped recess facing the well wall. A pad assembly groove is provided at the bottom of the U-shaped recess.

[0018] Furthermore, the device further includes a backing plate having an inserting portion and a supporting portion. The inserting portion engages with the backing plate mounting slot, and the supporting portion extends out of the backing plate mounting slot and supports the density probe. The length of the elongated hole satisfies the travel requirement of the density probe from the housing. When the density probe is extended from the housing, it can contact the wellbore wall. The upper and lower joints are each connected to an elliptical lifting lug.

[0019] The beneficial effects of the present invention are:

[0020] The density probe can be pushed against each other without power supply. The whole system adopts mechanical connection, which has high working reliability. It is applicable to horizontal wells, inclined wells, etc., effectively improving the logging accuracy and meeting the requirements of storage logging. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the overall structure of the adaptive well wall device;

[0022] Figure 2 Schematic diagram of the probe retracted into the main body when the wellbore is regular;

[0023] Figure 3 Schematic diagram of the probe automatically sliding out when the wellbore is irregular;

[0024] Figure 4 Schematic diagram of implementation in vertical well conditions;

[0025] Figure 5 Schematic diagram of the eccentric structure;

[0026] Figure 6 Schematic diagram of eccentric installation;

[0027] Figure 7 Axial projection of the eccentric;

[0028] Figure 8 Force analysis of eccentric contacting well wall at any point;

[0029] In the figure: 1, upper connector, 2, hose, 3, upper connector, 4, density probe, 5, main body, 6, lower connector, 7, lower connector, 8, eccentric. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is described in detail below with reference to the embodiments.

[0031] Example 1:

[0032] A self-adaptive well wall-adhering device mainly consists of an upper joint, an upper connector, a density probe, a lower connector, a main body, and a lower joint. The two ends of the main body are respectively connected to the upper joint and the lower joint. The main body is provided with a receiving portion, and the density probe is hinged to the receiving portion through the upper and lower connectors; one end of the lower connector is hinged to the receiving portion through a pin shaft and a pin hole, and the pin hole is a long hole, and the long hole slides with the pin shaft; when the density probe, the upper connector, and the lower connector are connected in a straight line, the overall maximum diameter of the main body, the density probe, the upper connector, and the lower connector is less than or equal to the minimum diameter of the upper and lower joints.

[0033] Both the upper and lower joints are fitted with eccentrics, with the heavier side of the eccentric facing the main body. The eccentrics are eccentric sleeves, with the lighter side having a longitudinal opening. The upper and lower connectors are H-shaped connectors. The accommodating portion is a U-shaped recess, with the opening facing the wellbore wall. A gasket mounting groove is provided at the bottom of the U-shaped recess.

[0034] The device also includes a backing plate, which is provided with an inserting portion and a supporting portion. The inserting portion plugs into the backing plate's mounting slot, and the supporting portion extends out of the backing plate's mounting slot to support the density probe. The length of the elongated hole meets the travel requirements of the density probe from the housing. When the density probe is extended from the housing, it can be in contact with the wellbore wall. The upper and lower joints are respectively connected to lifting lugs. Each lifting lug is elliptical in shape.

[0035] Example 2:

[0036] An adaptive fitting device consists of an upper connector, a hose, an upper connector, a main body, a lower connector, and other components. The upper and lower connectors, the main body, the probe connector, and the density probe form the four arms of a hinged four-bar mechanism. A waist-shaped hole beneath the lower connector adds a degree of freedom to the mechanism, allowing the density probe to more flexibly fit the wellbore wall.

[0037] When the well condition is good, the mechanism is passively retracted and the density probe is retracted into the main body. At this time, the density probe fits well with the well wall due to its own weight. Figure 2 shown.

[0038] When the well condition is bad, the mechanism opens passively under the action of the density probe's own gravity, and the density probe slides out from the main rod. Figure 3 As shown, it can adapt to severe well conditions within the movement range of the mechanism itself.

[0039] When measuring horizontal wells and highly deviated wells, in order to prevent the wear of the probe, the force against the well wall is the probe's own weight. When the instrument is in a vertical state, the outer busbar of the probe is on the outer circle of the instrument. In order to keep the probe close to the well wall when measuring in vertical wells, the device adopts the method of adding a pad to make the outer busbar of the probe protrude 1~2cm from the instrument. When the instrument is pushed on the back side of the probe, it can ensure that the probe is close to the well wall. The pad assembly groove under the main body allows the pad to be assembled and disassembled without disassembling the probe. The schematic diagram is as follows Figure 4 shown.

[0040] The eccentrics are installed at both ends of the device, so that the density probe is deflected and pressed against the well wall under the action of gravity, thus improving the quality of the density logging curve. Figure 5 , after installing the instrument, such as Figure 6 .

[0041] The deflection principle of the eccentric is as follows: Figure 7It can be seen that the circle formed by the axial projection of the eccentric (center O') is eccentric to the outer diameter circle of the instrument (center O), and the eccentricity is h. Since the instrument is heavy, the existence of the eccentric hardly affects the change of the center of gravity of the entire instrument. Therefore, no matter how the instrument deflects, the center of gravity remains at point O. Therefore, only when the instrument contacts the well wall at point A or point B, the instrument gravity has no eccentric torque. However, at point A, the center of gravity of the instrument is high and the potential energy is large. It is difficult to maintain balance during the drilling process. When any point N on the fin line contacts the well wall, as shown in the following example: Figure 4 , gravity will produce a deflection torque, causing the contact point to return to point B. Therefore, the center of gravity of the tool is stable at point B. At this time, the density probe is close to the well wall. Figure 8 shown.

[0042] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. An adaptive well wall-adhering device, comprising an upper joint, an upper connector, a density probe, a lower connector, a main body, and a lower joint, wherein the upper joint and the lower joint are connected at both ends of the main body respectively, and a receiving portion is provided on the main body, and the density probe is hinged to the receiving portion through the upper connector and the lower connector; one end of the lower connector is hinged to the receiving portion through a pin shaft and a pin hole, and the upper connector and the lower connector are H-shaped connectors; the receiving portion is a U-shaped recess, the opening of the U-shaped recess faces the well wall, and a pad assembly groove is provided at the bottom of the U-shaped recess; the pin hole is a long hole, and the long hole is slidably matched with the pin shaft; when the density probe, the upper connector, and the lower connector are connected in a straight line, the overall maximum diameter of the main body, the density probe, the upper connector, and the lower connector is less than or equal to the minimum diameter of the upper joint and the lower joint; When the well condition is good, the adaptive well wall-adhering device is passively retracted, and the density probe is retracted into the main body. At this time, the density probe fits well with the well wall due to its own weight. When the well condition is bad, the adaptive well wall-adhering device is passively opened under the action of the density probe's own gravity, and the density probe slides out from the main body to adapt to the harsh well condition within the movement range of the adaptive well wall-adhering device.

2. The adaptive well wall-adhering device according to claim 1, characterized in that: The upper joint and the lower joint are both sleeved with eccentrics, and the heavier side of the eccentrics faces the main body.

3. The adaptive well wall-adhering device according to claim 2, characterized in that: The eccentric is an eccentric sleeve structure, and a longitudinal opening is provided on a side with a light center of gravity.

4. The adaptive well wall-adhering device according to claim 1, characterized in that: It also includes a pad, which is provided with an inserting portion and a supporting portion. The inserting portion is plugged into the pad assembly slot, and the supporting portion extends out of the pad assembly slot to support the density probe.

5. The adaptive well wall-adhering device according to claim 4, characterized in that: The length of the long hole meets the travel requirement of the density probe protruding from the accommodating portion, and when the density probe protrudes from the accommodating portion, it can fit against the well wall.

6. The adaptive well wall-adhering device according to claim 5, characterized in that: The upper and lower joints are respectively connected with lifting ears.

7. The adaptive well wall-adhering device according to claim 6, characterized in that: The lifting ear is oval in shape.

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