CN102392634A - Measuring device and measuring method for well-cementing annular weight loss of cement slurry - Google Patents

Abstract

The present invention relates to a cementing annular cement slurry weight loss measurement device and a measurement method. The device is mainly composed of a base, a control panel, a vertical pillar, a slurry cylinder and a computer. The vertical pillar is connected to the slurry cylinder through a support shaft, and the The shaft is connected to the control panel; the slurry cylinder has a pressure hole, an inner cylinder, an outer cylinder and an annulus between the inner cylinder and the outer cylinder. The slurry cylinder is composed of sections, and each section has a temperature sensor, a pressure sensor and The cooling jacket is heated, and the slurry cylinder controls the eccentricity of the inner cylinder through the eccentric cover, and there are three pressure sensors at its lower part, and the temperature sensor and the pressure sensor transmit data to the computer respectively. The invention can simulate the different temperature differences that exist in the downhole temperature as the well depth changes. The acquisition and control is controlled by a computer, and the operation is simple and convenient. The eccentric cover is used to control the eccentricity of the casing, which is safe, stable and reliable. It is suitable for oil and natural gas cementing, Squeeze cement, cement and other operations.

Description

Cementing Annulus Cement Slurry Weight Loss Measurement Device and Measurement Method

technical field

The invention relates to a weightless measuring device and a measuring method for simulating the coagulation process of annular cement slurry under the conditions of different well depths, different annular space gaps and different well inclination angles, and is suitable for annular cement slurry in oil and natural gas well cementing operations after cementing Research on the law of weightlessness and gas channeling.

Background technique

During oil and natural gas exploration and development drilling, when the drill bit reaches a certain depth, the drill bit needs to be pulled out from the well, and a hollow steel pipe string called a casing is inserted into the well, and then inserted between the wellbore and the casing. Cement slurry is injected into the annular space of the well, and the well wall is consolidated after static solidification, which is referred to as cement injection. When the cement injection is just completed, the cement slurry is still in a liquid state. At this time, the pressure of the liquid in the annular space on the formation is the sum of the hydrostatic pressures of the slurry columns above the action point; because the density of the cement slurry is generally greater than that of the drilling fluid, it can play a role. To suppress the formation of the role. However, due to certain reasons, the cement slurry column will gradually reduce the pressure on its lower part or formation during the setting process, as if it has lost a part of its mass. This phenomenon is called the weight loss of cement slurry during the setting process (referred to as weight loss). During the coagulation process of oil well cement slurry, due to the transformation of cement slurry from a liquid state to a plastic state, its physical and chemical properties change significantly, resulting in a decrease in the effective liquid column pressure of the cement slurry acting on the bottom of the well. When the pressure drops below the formation pressure, oil, gas, and water will invade the annular space and rush to the wellhead, causing oil and gas to leak from the wellhead, or even uncontrollable blowout, which not only causes waste of oil and gas resources, but also seriously damages the environment. Come havoc. In the U.S. Gulf of Mexico, the cost of repairing gas channeling zones to kill wells is as high as $1 million per well per year. In my country's Sichuan Longgang, Xinjiang Tarim Basin, and Daqing Qingshen gas field, many wells have gas channeling and pressure phenomenon every year, which has not been solved well so far. The essential reason is that the understanding of the law of weightlessness is not clear. The root cause is that the existing devices have not been able to better simulate the underground working conditions for the test of the law of weightlessness. Not obvious.

Domestic related patents include utility model patents, such as oil well cement weight loss and gas-liquid channeling simulation test device (zl200720149001) and cementing slurry weight loss measurement device (ZL01251865.4). The current oil well cement slurry weight loss test device tests the weight loss state under actual working conditions such as wide and narrow gaps in the annular space, temperature difference, and well deviation.

Contents of the invention

The object of the present invention is to provide a cementing annulus cement slurry weight loss measurement device, which can more realistically simulate the weight loss law in the downhole state and lay the foundation for the research on anti-channeling measures.

Another object of the present invention is to provide a method for measuring the loss of cement slurry annular space by using the above-mentioned device. Downhole conditions and weightlessness in high pressure environments.

In well cementing, the cement slurry is in different temperature, pressure and annulus conditions downhole, and different wellbore structures and downhole conditions lead to different weight loss laws of the cement slurry. In order to obtain the weight loss law of different consolidation processes of oil well cement slurry in the downhole environment, the present invention adopts the following technical scheme:

1. Well depth simulation. The kettle body height of the measuring instrument of the present invention is 1 meter, and the maximum pressure is 10 MPa, which can simulate the pressure generated by a 1000-meter water column.

2. Change control of cement slurry column temperature. In the cementing process of oil and gas wells, after the cement slurry is replaced in place, the temperature of the formation and the temperature of the cement slurry column are also different due to different depths, and the temperature difference of the cement slurry column will be large as the depth increases. During the cement slurry consolidation process, the temperature has a great influence on the cement stone strength. At different temperatures, the compressive strength of the cement slurry is very different. Therefore, it is necessary to simulate the temperature difference of the cement slurry column. The present invention adopts multiple heating and cooling jackets to realize the continuous gradient change of cement slurry column temperature from bottom to top, and according to the ground temperature gradient of 2°C/100m, a temperature difference of 20°C is generated in a well section of about 1000m.

3. Casing eccentric control. During the process of running the casing before the cementing of oil and gas wells, due to well conditions, geology and other reasons, after the casing is run into the formation, the casing is not centered and deviates and cannot be remedied. Only when the casing is eccentric is the cementing done. The present invention adopts the upper and lower eccentric covers to control the eccentricity of the casing, and simulates being in different positions of the shaft (the eccentricities are 0, 0.2, and 0.6) by making covers with different eccentric degrees. Eccentricity = (distance between inner and outer cylinder centers) / (difference in radius of inner and outer cylinders).

4. Casing tilt control. In the cementing of deviated wells, extended-reach wells, and horizontal wells, the wellbore and the casing have a certain degree of relative inclination. The invention adjusts the inclination degree of the whole wellbore through the outer support of the outer cylinder, and realizes the angle conversion of 0 to 90 degrees.

5. Pressure acquisition. There are three pressure sensors at the bottom of the measuring instrument of the present invention to measure different pressure changes.

6. Annular space simulation. The annular gap and the actual annular gap are equal. The annulus is made of different sizes of inner cylinders based on geometric similarity, and the annulus gap can be changed.

The cementing annular cement slurry weight loss measurement device is mainly composed of a base, a control panel, a vertical pillar, a slurry cylinder, and a computer. It is characterized in that the measuring device is located on the base, and the vertical pillar is connected to the slurry cylinder through a support shaft. , and is connected with the control panel through the rotating shaft, which can realize the rotation from 0° to 90°; the slurry cylinder has a pressure hole, an inner cylinder, an outer cylinder and an annular space between the inner cylinder and the outer cylinder, and the slurry cylinder It is a combination of sections, each section has a temperature sensor, a pressure sensor and a heating and cooling jacket. The slurry cylinder controls the eccentricity of the inner cylinder through an eccentric cover. The upper eccentric cover is the upper top cover, and the lower eccentric cover is the lower bottom cover. There are three pressure sensors at the bottom of the slurry cylinder. The control panel controls the temperature of each section of the slurry cylinder and monitors the pressure of each section of the slurry cylinder. The temperature sensor and the pressure sensor transmit data through the temperature sensor data interface and the pressure sensor data interface respectively. to the computer, the computer automatically records and displays the temperature and pressure changes of the cement slurry, and draws the temperature and pressure change curves.

The control panel of the present invention controls the temperature of the cement slurry column from the bottom to the top to realize a continuous gradient change through the heating and cooling jacket and the temperature sensor of each section of the slurry cylinder, thereby simulating the different changes of the downhole temperature with the well depth. The eccentric cover controls the eccentricity of the inner cylinder, and multiple eccentric covers with different eccentricities can simulate various downhole casing eccentric conditions. The three pressure sensors at the bottom measure the pressure in all directions when eccentric. The vertical pillar is connected with the control panel through the rotating shaft, which can realize the rotation of the whole slurry cylinder from 0° to 90°.

Utilize above-mentioned device to measure the method for cement slurry annular weight loss, comprise the following steps successively:

(1) To prepare oil well cement slurry, open the upper top cover of the slurry cylinder, pour the cement slurry into the annular space between the inner cylinder and the outer cylinder, and seal it with a cover;

(2) Connect the pressure source through the pressure hole, and increase the pressure to the pressure required for the experiment;

(3) The control panel controls the temperature of the cement slurry column from the bottom to the top through the heating and cooling jacket to achieve a continuous gradient change to reach the temperature required for the experiment;

(4) The temperature sensor and the pressure sensor transmit the data to the computer, and the computer displays the temperature and pressure changes of the cement slurry;

(5) According to the temperature and pressure change curves drawn by the computer, determine the law of weight loss of the cement slurry during the downhole condensation process.

Compared with the prior art, the present invention has the following beneficial effects: (1) It can simulate the different temperature differences of the downhole temperature as the well depth changes, and adopts multiple heating and cooling jackets and temperature sensors to control the temperature difference of the slurry column in real time to achieve the design The required temperature difference is collected and controlled by computer, and the operation is simple and convenient, which solves the problem of downhole temperature change. (2) The present invention uses the eccentric cover to control the eccentricity of the bushing, which is safe, stable and reliable. (3) According to the fact that the annular gap is equal to the actual annular gap, various annular gaps can be realized. (4) Three pressure sensors are installed at the bottom to measure pressure changes in different directions.

Description of drawings

Fig. 1 is a structural schematic diagram of the cementing annular cement slurry weight loss measuring device of the present invention.

Figure 2 shows the changes in the pressure of the cement slurry column when the temperature is 30°C with grade G cement + 2% microsilicon + 1% dispersant + 1% coagulant, and the pressure is normal pressure.

Figure 3 shows the changes in the pressure of the cement slurry column when the temperature is 50°C with grade G cement + 2% microsilicon + 1% dispersant + 1% coagulant, and the pressure is normal pressure.

Figure 4 shows the changes in the pressure of the cement slurry column when the bottom temperature is 30°C and the temperature rises gradually, and the top temperature is 50°C. pressure.

Detailed ways

Further illustrate the present invention according to accompanying drawing and embodiment below.

Referring to Fig. 1, the cementing annular cement slurry weight loss measurement device is mainly composed of a base 16, a control panel 14, a vertical pillar 12, a slurry cylinder, and a computer 9. It is characterized in that the measurement device is located on the base, and the vertical The pillar is connected with the pulp cylinder through the support shaft 15, and connected with the control panel through the rotating shaft 13, which can realize the rotation from 0 to 90 degrees; the pulp cylinder has a pressure hole 1, an inner cylinder 3, an outer cylinder 4 and an inner The annular space between the cylinder and the outer cylinder, the slurry cylinder is composed of sections, each section has a temperature sensor 5, a pressure sensor 6 and a heating and cooling jacket 7, and the slurry cylinder has an upper top cover 2 and a lower bottom cover 8, There are three pressure sensors 17 in the lower part of the slurry cylinder. The temperature sensor 5, pressure sensors 6 and 17 transmit data to the computer 9 through the temperature sensor data interface 10 and the pressure sensor data interface 11 respectively.

The method of measuring the weight loss of the cement slurry annular space by using the cementing annular cement slurry weight loss measurement device is to prepare the same oil well cement slurry according to the API standard (see Table 1), according to the vertical well, the casing is centered, the small annular space gap, and according to different test conditions experimenting. The experimental results of Example 1, Example 2, and Example 3 in Table 1 correspond to Figure 2, Figure 3, and Figure 4, respectively.

It can be seen from the curve in the figure that the formation of a certain structure by the cement slurry hydration reaction is not weightless from the beginning. The cement slurry is liquid at the beginning and will generate pressure on the bottom in the form of a liquid column. With the cement slurry hydration reaction, a certain structure will be formed. , the pressure of the cement slurry liquid column will be gradually distributed into these structures, and the pressure on the bottom will gradually decrease. As the cement slurry solidifies, this part of the pressure will eventually decrease to zero. Due to the difference in temperature, the hydration exothermic reaction solution is different. The higher the temperature, the faster the hydration reaction, the shorter the time for the cement slurry to form the structure, and the shorter the weight loss time.

Table 1 Test results of cementing annular cement slurry weight loss measurement device

Claims (2)

1. well cementation annular space cement paste weightless measurement device; Mainly form by base (16), control panel (14), upright support post (12), slurry tube, computer (9); It is characterized in that this device is positioned on the base, said upright support post is connected with the slurry tube through back shaft (15); Be connected with control panel through axis of rotation (13) again, can realize spending to the rotation of 90 degree from 0; Said slurry tube has the annular space between pressurization hole (1), inner core (3), urceolus (4) and the inner core urceolus; Said slurry tube is the segmentation combination; Each section all has temperature pick up (5), pressure sensor (6) and heating coolant jacket (7); Said slurry tube has top top cover (2) and bottom bottom (8); A said slurry tube bottom also has three pressure sensors (17), and said temperature pick up (5), pressure sensor (6) arrive computer (9) through temperature pick up data-interface (10), pressure sensor data interface (11) with transfer of data respectively with (17).

2. the method for utilizing measurement mechanism as claimed in claim 1 that well cementation annular space cement paste weightlessness is measured may further comprise the steps successively:

(1) cementing slurry for well that makes up oil is opened the top top cover of slurry tube, cement paste is poured in the annular space between inner core and the urceolus, and sealed;

(2) connect pressure source through the pressurization hole, pressure is added to the required pressure of experiment;

(3) control panel is realized successional change of gradient from top to bottom through the temperature of heating coolant jacket control cement paste post, and it is temperature required to reach experiment;

(4) to computer, computer shows the temperature, pressure situation of change of cement paste with transfer of data for temperature pick up, pressure sensor;

(5), confirm the weightless rule of cement paste in the condensation process of down-hole according to the temperature and pressure change curve of computer drawing.

Images