A density logging method

Abstract

The present invention relates to the field of well logging technology, and discloses a density logging method. The density logging method comprises: step S1, a gravity eccentric is installed on a density probe of a density logging instrument through an adapter assembly; step S2, the density probe is pre-attached to the well wall, the center of gravity of the gravity eccentric deviates from the axis of the density probe toward the well wall by a preset distance, and the gravity of the gravity eccentric produces a torque on the density probe, so that the density probe is closely attached to the well wall; step S3, the density of the liquid to be measured in the well is detected by the density probe. In the density logging method provided by the present invention, during measurement, the density probe is pre-attached to the well wall, because the gravity eccentric is installed on the density probe through the adapter assembly, the center of gravity of the gravity eccentric deviates from the axis of the density probe toward the well wall by a preset distance, and the gravity of the gravity eccentric produces a torque on the density probe, so that the density probe is closely attached to the well wall, thereby improving the accuracy of the density probe logging result, being easy to operate, and saving time and effort.

Description

Technical Field

[0001] The present invention relates to the field of well logging technology, and in particular to a density well logging method. Background Art

[0002] There are mainly three kinds of fluids in production wells: oil, gas and water. These three kinds of fluids have obvious differences in density. Fluid density measurement is to use density logging instruments to measure the density of fluids in production wells. By measuring the fluid density, the purpose of identifying the fluid type and dividing the fluid interface can be achieved. When measuring, the density probe of the density logging instrument needs to be close to the well wall to make the measured data more accurate and effective.

[0003] However, when measuring horizontal wells, since the density probe itself is relatively heavy, the pushing force of the density logging instrument's pusher on the density probe is relatively small, resulting in the density probe being unable to adhere closely to the well wall, thus affecting the measurement results. Summary of the invention

[0004] Based on the above problems, the object of the present invention is to provide a density logging method, which can achieve close contact between the density probe and the well wall.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A density logging method, comprising:

[0007] Step S1, the gravity eccentric piece is installed on the density probe of the density logging tool through the adapter assembly;

[0008] Step S2, the density probe is pre-attached to the well wall, the center of gravity of the gravity eccentric piece deviates from the axis of the density probe by a preset distance toward the well wall, and the gravity of the gravity eccentric piece generates a torque on the density probe, so that the density probe is closely attached to the well wall;

[0009] Step S3: Detecting the density of the liquid to be tested in the well by using the density probe.

[0010] As a preferred solution of the density logging method of the present invention, the step S1 includes step S11: the adapter assembly includes an adapter, one end of the adapter is connected to the density probe, and the other end is connected to the gravity eccentric member.

[0011] As a preferred embodiment of the density logging method of the present invention, the step S11 includes step S111: the adapter assembly also includes a pressure block, which is arranged in the adapter, one end of the pressure block is abutted against the density probe, and the other end is abutted against the gravity eccentric member.

[0012] As a preferred embodiment of the density logging method of the present invention, the step S111 includes step S1111: a first anti-rotation key is provided at one end of the pressure block facing the density probe, and a first anti-rotation groove cooperating with the first anti-rotation key is provided on the density probe.

[0013] As a preferred embodiment of the density logging method of the present invention, the step S1111 includes step S11111: a second anti-rotation key is provided at one end of the pressure block facing the gravity eccentric member, and a second anti-rotation groove cooperating with the second anti-rotation key is provided on the gravity eccentric member.

[0014] As a preferred solution of the density logging method of the present invention, the step S111 further includes a step S1112: an O-ring is sleeved on the pressure block, and the O-ring is clamped between the adapter and the pressure block.

[0015] As a preferred embodiment of the density logging method of the present invention, the step S111 also includes step S1113: the adapter assembly also includes a hole retaining ring, the hole retaining ring is arranged in the adapter and clamped between the pressure block and the gravity eccentric member.

[0016] As a preferred embodiment of the density logging method of the present invention, the step S11 also includes step S112: the adapter assembly also includes a connecting piece, the connecting piece is rotatably mounted on the gravity eccentric piece, and the connecting piece is provided with an external threaded portion threadedly connected to the adapter.

[0017] As a preferred solution of the density logging method of the present invention, the step S112 includes step S1121: a limiting portion is recessed on the outer peripheral wall of the gravity eccentric member, and the connecting member is rotatably sleeved on the limiting portion.

[0018] As a preferred solution of the density logging method of the present invention, the step S1121 includes step S11211: the connecting piece is formed by splicing two half-ring structures.

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

[0020] The density logging method provided by the present invention has the density probe pre-attached to the well wall during measurement. Since the gravity eccentric is installed on the density probe through the adapter assembly, the center of gravity of the gravity eccentric deviates from the axis of the density probe toward the well wall by a preset distance. The gravity of the gravity eccentric produces a torque on the density probe, so that the density probe is closely attached to the well wall, thereby improving the accuracy of the density probe logging results. The operation is convenient, and time and labor are saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0022] Figure 1 It is a schematic flow chart of a density logging method provided in a specific embodiment of the present invention;

[0023] Figure 2 It is a structural schematic diagram of a density logging instrument used in a density logging method provided in a specific embodiment of the present invention;

[0024] Figure 3 It is a schematic diagram of an explosion of a density logging instrument used in a density logging method provided in a specific embodiment of the present invention.

[0025] In the figure:

[0026] 1-density probe; 2-gravity eccentric piece; 3-adapter assembly;

[0027] 11- first anti-rotation groove;

[0028] 21- second anti-rotation groove; 22- limiting portion;

[0029] 31- adapter; 32- pressure block; 33- retaining ring for hole; 34- connecting piece;

[0030] 321-first anti-rotation key; 322-second anti-rotation key; 323-O-ring;

[0031] 341-external threaded portion; 342-semi-ring structure;

[0032] 100-well wall. DETAILED DESCRIPTION

[0033] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] like Figure 1 As shown, this embodiment provides a density logging method, the density logging method adopts Figure 2 and Figure 3 The density logging tool shown in the figure performs density measurement, and the density logging tool comprises a density probe 1, a gravity eccentric 2 and an adapter assembly 3. The density logging method comprises:

[0037] Step S1, the gravity eccentric member 2 is installed on the density probe 1 of the density logging tool through the adapter assembly 3;

[0038] Step S2, the density probe 1 is pre-adhered to the well wall 100, the center of gravity of the gravity eccentric piece 2 is deviated from the axis of the density probe 1 by a preset distance toward the well wall 100, and the gravity of the gravity eccentric piece 2 generates a torque on the density probe 1, so that the density probe 1 is closely attached to the well wall 100;

[0039] Step S3: Detect the density of the liquid to be tested in the well by using the density probe 1.

[0040] It should be noted that the density probe 1 can be a commonly used liquid density sensor on the market, which is a prior art. There are many types of commonly used liquid density sensors, such as vibration liquid density sensors, capacitive liquid density sensors, ray-type liquid density sensors and ultrasonic liquid density sensors. These liquid density sensors have their own characteristics in the measurement field: vibration liquid density sensors and capacitive liquid density sensors are low in cost and are widely used in measurement, but the measurement accuracy is not high and maintenance is more troublesome; ray-type liquid density sensors can perform non-contact measurement, but there is radiation hazard of rays, so they are less used; ultrasonic liquid density sensors have a wide range of applications, are easy to maintain, have high measurement accuracy, and are harmless to the human body. They are the most promising sensors for realizing dynamic measurement of liquid density.

[0041] To facilitate installation of the gravity eccentric member 2 on the density probe 1, optionally, step S1 includes step S11: the adapter assembly 3 includes an adapter 31, one end of the adapter 31 is connected to the density probe 1, and the other end is connected to the gravity eccentric member 2. In this embodiment, the adapter 31 can be threadedly connected to the density probe 1. The adapter 31 is sleeve-shaped, and the interior of the adapter 31 is a multi-section structure with different inner diameters.

[0042] To ensure that the gravity eccentric piece 2 is tightly connected to the density probe 1, optionally, step S11 includes step S111: the adapter assembly 3 also includes a pressure block 32, which is arranged in the adapter 31, and one end of the pressure block 32 is in contact with the density probe 1, and the other end of the pressure block 32 is in contact with the gravity eccentric piece 2. When the gravity eccentric piece 2 is tightly connected to the density probe 1, the pressure block 32 bears the extrusion force between the gravity eccentric piece 2 and the density probe 1, thereby preventing damage to the density probe 1.

[0043] To prevent the pressure block 32 and the density probe 1 from rotating relative to each other, optionally, step S111 includes step S1111: a first anti-rotation key 321 is provided at one end of the pressure block 32 facing the density probe 1 , and a first anti-rotation groove 11 cooperating with the first anti-rotation key 321 is provided on the density probe 1 .

[0044] To prevent the pressure block 32 from rotating relative to the gravity eccentric member 2, optionally, step S1111 includes step S11111: a second anti-rotation key 322 is provided at one end of the pressure block 32 facing the gravity eccentric member 2, and a second anti-rotation groove 21 cooperating with the second anti-rotation key 322 is provided on the gravity eccentric member 2. Through the cooperation of the first anti-rotation key 321 and the first anti-rotation groove 11, and the cooperation of the second anti-rotation key 322 and the second anti-rotation groove 21, it can be ensured that the center of gravity of the gravity eccentric member 2 is always located on the same side of the axis of the density probe 1 as the contact surface of the density probe 1 and the well wall 100, so as to ensure that the gravity of the gravity eccentric member 2 produces a torque on the density probe 1, so that the density probe 1 is closely contacted with the well wall 100.

[0045] Optionally, step S111 further includes step S1112: an O-ring 323 is sleeved on the pressure block 32, and the O-ring 323 is sandwiched between the adapter 31 and the pressure block 32. The pressure block 32 achieves an interference fit with the adapter 31 through the O-ring 323, thereby enhancing the connection strength between the pressure block 32 and the adapter 31.

[0046] Optionally, step S111 further includes step S1113: the adapter assembly 3 further includes a hole retaining ring 33, which is disposed in the adapter 31 and clamped between the pressure block 32 and the gravity eccentric member 2. The assembly error between the pressure block 32 and the gravity eccentric member 2 can be compensated by adjusting the number of the hole retaining rings 33.

[0047] To facilitate the connection between the gravity eccentric member 2 and the adapter 31, optionally, step S11 further includes step S112: the adapter assembly 3 further includes a connecting member 34, the connecting member 34 is rotatably sleeved on the gravity eccentric member 2, and the connecting member 34 is provided with an external thread portion 341 threadedly connected to the adapter 31. An internal thread is provided on the inner wall of the adapter 31, and the connecting member 34 on the gravity eccentric member 2 is rotated to screw the connecting member 34 into the adapter 31, and the gravity eccentric member 2 is connected to the adapter 31 through the threaded connection of the external thread portion 341 and the internal thread of the adapter 31, thereby realizing the connection between the gravity eccentric member 2 and the adapter 31.

[0048] To prevent the connecting member 34 from axial movement, optionally, step S112 includes step S1121: a limit portion 22 is recessed on the outer peripheral wall of the gravity eccentric member 2, and the connecting member 34 is rotatably sleeved on the limit portion 22. To facilitate assembly, optionally, step S1121 includes step S11211: the connecting member 34 is spliced ​​by two semi-ring structures 342. The two semi-ring structures 342 can be connected by bolts and nuts.

[0049] When the gravity eccentric piece 2 is installed on the density probe 1 of the density logging instrument through the adapter assembly 3, first, the adapter 31 is tightened with the density probe 1, and the pressure block 32 with the O-ring 323 is inserted into the adapter 31 to ensure that the first anti-rotation key 321 of the pressure block 32 is embedded in the first anti-rotation groove 11 of the density probe 1 to complete the radial positioning of the pressure block 32, and the hole retaining ring 33 is installed in the adapter 31 to complete the axial positioning of the pressure block 32; then, the two semi-ring structures 342 are spliced ​​together. The limiting part 22 of the gravity eccentric piece 2 is placed on the connecting piece 34 formed by the two semi-ring structures 342, and it is ensured that the connecting piece 34 formed by the two semi-ring structures 342 can rotate on the gravity eccentric piece 2; finally, the second anti-rotation groove 21 of the gravity eccentric piece 2 is aligned with the second anti-rotation key 322 of the adapter 31, and the gravity eccentric piece 2 is installed into the adapter 31. By rotating the connecting piece 34, the external threaded portion 341 of the connecting piece 34 is screwed into the internal thread in the adapter 31, thereby connecting the gravity eccentric piece 2 and the density probe 1 into one body, and the installation is completed.

[0050] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A density logging method, characterized in that: include: Step S1, the gravity eccentric member (2) is installed on the density probe (1) of the density logging instrument through the adapter assembly (3); Step S2, the density probe (1) is pre-adhered to the well wall (100), the center of gravity of the gravity eccentric piece (2) is deviated from the axis of the density probe (1) by a preset distance toward the well wall (100), and the gravity of the gravity eccentric piece (2) generates a torque on the density probe (1), so that the density probe (1) is closely adhered to the well wall (100); Step S3, detecting the density of the liquid to be tested in the well by means of the density probe (1); The step S1 comprises a step S11: the adapter assembly (3) comprises an adapter (31), one end of the adapter (31) is connected to the density probe (1), and the other end of the adapter (31) is connected to the gravity eccentric member (2); The step S11 comprises a step S111: the adapter assembly (3) further comprises a pressure-bearing block (32), the pressure-bearing block (32) being arranged in the adapter (31), one end of the pressure-bearing block (32) being in contact with the density probe (1), and the other end of the pressure-bearing block (32) being in contact with the gravity eccentric member (2); The step S111 comprises step S1111: a first anti-rotation key (321) is provided at one end of the pressure block (32) facing the density probe (1), and a first anti-rotation groove (11) matched with the first anti-rotation key (321) is provided on the density probe (1); The step S1111 comprises step S11111: a second anti-rotation key (322) is provided at one end of the pressure block (32) facing the gravity eccentric member (2), and a second anti-rotation groove (21) cooperating with the second anti-rotation key (322) is provided on the gravity eccentric member (2); The step S111 further includes a step S1113: the adapter assembly (3) further includes a hole retaining ring (33), the hole retaining ring (33) is arranged in the adapter (31), and is clamped between the pressure block (32) and the gravity eccentric member (2); The step S11 also includes a step S112: the adapter assembly (3) also includes a connecting piece (34), the connecting piece (34) is rotatably sleeved on the gravity eccentric piece (2), and the connecting piece (34) is provided with an external threaded portion (341) threadedly connected to the adapter (31).

2. The density logging method according to claim 1, characterized in that: The step S111 further comprises a step S1112: an O-ring (323) is sleeved on the pressure-bearing block (32), and the O-ring (323) is clamped between the adapter (31) and the pressure-bearing block (32).

3. The density logging method according to claim 1, characterized in that: The step S112 comprises a step S1121: a limiting portion (22) is recessed on the outer peripheral wall of the gravity eccentric member (2), and the connecting member (34) is rotatably sleeved on the limiting portion (22).

4. The density logging method according to claim 3, characterized in that: The step S1121 includes step S11211: the connecting piece (34) is formed by splicing two half-ring structures (342).

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