A shale oil reservoir oil content evaluation system

Abstract

The present invention discloses a shale oil reservoir oil content evaluation system, belonging to the field of oil exploration technology, comprising a drilling unit, a coring unit, a grouting unit, and a detection unit. A well is drilled using an exploration drill bit, a core is extracted using a grinding drill bit, grouting is performed in the well, a crushing tank is centrifugally crushed on the core, a collection bottle is vacuumed using an air pump, an external pipe is connected to a gas nozzle, the collection bottle is opened to suck out the gas inside the crushing tank, the crushing tank is heated using a heating wire, oil is obtained by distillation, the oil, slag, and concrete blocks are weighed, and gas concentrations are measured. By using two drill rods during drilling sampling, one drill rod remains stationary after drilling the required core, and grouting is performed on the bottom of the well, the drill rod is used to ensure that the kerogen in the sample core does not leak out from the side, and by pouring concrete, the kerogen in the sample core can be promptly ensured not to leak out from the bottom, and the crude oil at the bottom can be prevented from surging.

Description

Technical Field

[0001] The present invention belongs to the technical field of petroleum exploration, and in particular relates to a shale oil reservoir oil content evaluation system. Background Art

[0002] Shale oil refers to the petroleum resources contained in shale formations dominated by shale, including the oil in the pores and cracks of mudstone, as well as the oil resources in the adjacent layers and interlayers of dense carbonate or clastic rocks in the mudstone formation. Among them, the use of rock samples for oil and gas analysis is one of the basic tasks of comprehensive evaluation research. The oil and gas evaluation of oil shale mainly includes liquid hydrocarbons and gaseous hydrocarbons.

[0003] Since kerogen in rocks has outstanding fluidity and diffusion properties, it is easy to cause kerogen to seep out during core drilling, resulting in a decrease in the kerogen content in the sample, which is not up to standard during testing and will lead to incorrect judgment of the fluidity and recoverability of shale oil in the formation represented by the rock sample. Summary of the Invention

[0004] In view of the problem that existing samples are prone to kerogen seepage during drilling, the present invention provides a shale oil reservoir oil content evaluation system, which uses a double hollow drill bit for exploration drilling, uses a large drill bit to ensure that the kerogen on the side of the sample will not be lost, and performs grouting and sealing on the bottom of the well, thereby ensuring the kerogen content inside the sample.

[0005] To solve the above problems, the present invention adopts the following technical solutions.

[0006] A shale oil reservoir oil content evaluation system includes a drilling unit, a coring unit, a grouting unit, and a detection unit. The drilling unit uses an exploration drill bit to drill into a target area to obtain a core sample of kerogen-containing shale. The coring unit uses a small grinding drill bit inserted into the exploration drill bit to crush and extract the core sample. The grouting unit uses a grouting device to inject concrete into the bottom of the well when the exploration drill bit drills to a specified depth, thereby sealing the bottom of the well with concrete blocks to prevent crude oil from upwelling and kerogen from infiltrating the core sample. When the core sample is completely extracted, the well is quickly grouted, and the exploration drill bit is lifted during the grouting. The detection unit crushes the core to obtain kerogen, slag, and natural gas. The kerogen and slag are weighed separately and the natural gas concentration is detected. The concrete block is then extracted and weighed. The porosity of the shale is obtained by comparing the weight of the concrete block with the weight of the core, and the oil content of the pores is obtained based on the kerogen.

[0007] Preferably, the exploration drill bit used in the drilling unit is a hollow drill bit, and the exploration drill bit is provided with wall holes to facilitate grouting and sealing of the well bottom, and the outer diameter of the grinding drill bit used in the coring unit is smaller than the inner diameter of the exploration drill bit.

[0008] Preferably, the grouting unit is poured with C concrete. The entire grouting unit is divided into two parts. The first part is grouting after the exploration drill bit reaches a predetermined depth. Its main function is to seal the bottom of the mine to prevent the kerogen in the ore core from penetrating and the bottom kerogen from rising. The well wall will not penetrate due to the squeezing of the exploration drill bit. The secondary grouting is carried out after the ore core is brought out. First, it can prevent mine collapse. Second, it can effectively prevent crude oil around the mine from entering the mine, causing crude oil at other sampling points to leak from the oil shale. Finally, the underground concrete block can be brought out and compared with the quality of the ore core. It should be noted that when extracting the concrete block, a casing needs to be added to prevent mine collapse.

[0009] Preferably, the detection unit includes two units: extraction and weighing. The extraction unit includes crushing the ore core and collecting the gas in the ore core. The weighing unit includes weighing the extracted material and slag while weighing the concrete blocks in the mine.

[0010] Preferably, the extraction unit in the detection unit needs to use a centrifugal crushing device for crushing the ore core. The centrifugal crushing device includes a crushing tank and an equipment box, and a fixed frame is integrally connected to the equipment box. At the same time, a bracket is rotatably connected to the fixed frame, and the crushing tank is fixedly connected in the bracket.

[0011] Preferably, a heating wire is installed at the bottom of the crushing tank, and a protective plate is provided outside the heating wire. A screen is provided inside the crushing tank and above the protective plate. At the same time, short plates are welded at both ends of the inner wall of the crushing tank and connected to the screen pins. An air nozzle is installed at the port of the crushing tank.

[0012] Preferably, a drive is installed inside the equipment box, and a belt is sleeved on the drive. A rotating shaft is connected to the outer wall of the equipment box close to the crushing tank, and the other end of the belt is sleeved on the rotating shaft. The rotating shaft is connected to one end of the bracket, and the other end of the bracket is connected to a handwheel.

[0013] Preferably, the equipment box is also equipped with an air pump, and the air pump input end is connected to a collection bottle, and an air inlet pipe and a pressure gauge are installed at the end of the collection bottle, and the air inlet pipe is connected to the air inlet nozzle through an external pipe.

[0014] A shale oil reservoir oil content evaluation system includes the following steps:

[0015] Drilling out the mine using an exploration drill bit

[0016] Extracting ore cores using abrasive drill bits

[0017] Grouting in mines

[0018] Centrifugal crushing of ore cores using crushing tanks

[0019] Use the air pump to vacuum the collection bottle, connect it to the air nozzle through the external pipe, open the collection bottle to suck out the gas inside the crushing tank

[0020] Use heating wire to heat the crushing tank

[0021] Obtaining petroleum by distillation

[0022] Weigh oil, slag, and concrete blocks and measure gas concentrations.

[0023] Preferably, the gas content per unit mass in the rock sample is calculated based on the fixed capacity of the crushing tank and the gas concentration, and the ratio of the gas content per unit mass to the oil content per unit mass is determined; and the ratio is projected onto a reservoir oil and gas evaluation chart to determine the fluidity and recoverability of the shale oil in the formation represented by the rock sample.

[0024] Beneficial effects

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) In the present invention, two drill rods are used when drilling and sampling. After one of the drill rods drills out the required ore core, it remains stationary and grouting is performed on the bottom of the mine. The drill rod is used to ensure that the kerogen in the sample ore core will not flow out from the side. At the same time, by pouring concrete, the kerogen in the sample ore core can be ensured not to flow out from the bottom in time, and the crude oil at the bottom can be prevented from surging, thereby preventing misjudgment of the oil content in the later stage. The sample ore core is then drilled by another drill rod, so that a relatively full sample can be taken out, which is conducive to the later calculation of the oil content.

[0027] (2) In the present invention, since oil shale usually contains gaseous hydrocarbons, the concentration detection of gaseous hydrocarbons is also one of the evaluation criteria for the recoverability of shale oil. The sample core is crushed by a centrifugal crushing device, which can completely release the gas in the sample core and improve the extraction rate when extracting oil in the later stage. The specific method is: adding steel balls and other materials that can hit the sample core in the crushing tank, and driving the bracket connected to the crushing tank to rotate through the driver and belt. In the initial stage, it performs a semi-circular reciprocating motion so that the steel balls hit the sample core to complete the crushing. In the later stage, it performs a unidirectional circular rotation to use centrifugal force to promote the rapid precipitation of gas.

[0028] (3) In the present invention, the gas in the crushing tank is extracted by a gas extraction device composed of an air pump and a collecting bottle. Since the volume capacity of the crushing tank is fixed, the unit mass gas content in the rock sample is calculated based on the fixed capacity of the crushing tank and the gas concentration. The oil obtained by extraction is a more intuitive evaluation standard for judging the recoverability of shale oil. The ratio is projected onto the reservoir oil and gas evaluation plate to judge the fluidity and recoverability of the shale oil in the stratum represented by the rock sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the structure of a shale oil reservoir oil content evaluation system in the present invention;

[0030] Figure 2 This is a schematic structural diagram of the core separation system of the present invention;

[0031] Figure 3 Schematic diagram of the structure of the centrifugal crushing device in the present invention;

[0032] Figure 4 This is a schematic diagram of the internal structure of the crushing tank in the present invention;

[0033] Figure 5 This is a structural diagram of the equipment box in the present invention.

[0034] The correspondence between the labels and component names in the figure is as follows: 1. Equipment box; 2. Bracket; 3. Crushing tank; 4. Handwheel; 5. Fixing frame; 6. Screen; 7. Heating wire; 8. Guard plate; 9. Air nozzle; 10. Pressure gauge; 11. Collecting bottle; 12. Rotating shaft; 13. Belt; 14. Drive; 15. Air pump. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with specific embodiments.

[0036] In the show Figure 1 A shale oil reservoir oil content evaluation system provided in the present invention includes a drilling unit, a coring unit, a grouting unit and a detection unit.

[0037] Drilling unit: Use an exploration drill bit to drill the target area to obtain core samples of oil shale containing kerogen. The exploration drill bit used in the drilling unit is a hollow drill bit with wall holes to facilitate grouting and plugging at the bottom of the well;

[0038] Coring unit: A small grinding drill bit is inserted into the exploration drill bit to crush and extract the core sample. The exploration drill bit is used to ensure that the kerogen in the sample core does not leak out from the side. The outer diameter of the grinding drill bit is smaller than the inner diameter of the exploration drill bit, making it easier to insert;

[0039] Grouting unit: When the exploration drill bit reaches the specified depth, concrete is first injected into the bottom of the well through the grouting equipment, thereby sealing the bottom of the mine with concrete blocks to prevent crude oil from rising and kerogen from penetrating the core sample. When the core sample is completely extracted, the mine is quickly grouted, and the exploration drill bit is lifted during the grouting process;

[0040] Detection unit: After the ore core is crushed, kerogen, slag and natural gas are obtained. The kerogen and slag are weighed separately and the natural gas concentration is tested. The concrete block is then extracted and weighed. The porosity of the shale is obtained by comparing the weight of the concrete block and the weight of the ore core, and the oil content in the pores is obtained based on the kerogen.

[0041] exist Figure 1 and 2 In the process, the grouting unit is poured with C30 concrete. The whole grouting unit is divided into two parts. The first part is grouting after the exploration drill bit reaches the predetermined depth. Its main function is to seal the bottom of the mine to prevent the infiltration of kerogen in the ore core and the upwelling of the bottom kerogen. The well wall will not seep due to the squeezing of the exploration drill bit. The secondary grouting is carried out after the ore core is brought out. First, it can prevent mine collapse. Second, it can effectively prevent the crude oil around the mine from entering the mine, causing the crude oil at other sampling points to leak from the oil shale. Finally, the underground concrete block can be brought out and compared with the quality of the ore core. It should be noted that when extracting the concrete block, a casing needs to be added to prevent mine collapse. The detection unit includes two units, extraction and weighing. The extraction unit includes crushing the ore core and collecting the gas in the ore core. The weighing unit includes weighing the extracted material and slag while weighing the concrete blocks in the mine.

[0042] exist Figure 3 In the extraction unit of the detection unit, a centrifugal crushing device is required for crushing the ore core. The centrifugal crushing device includes a crushing tank 3 for crushing the sample ore core and an equipment box 1, and a fixed frame 5 is integrally connected to the equipment box 1. At the same time, a bracket 2 is rotatably connected to the fixed frame 5, and the crushing tank 3 is fixedly connected in the bracket 2.

[0043] exist Figure 4 A heating wire 7 for heating the crushed sample core is installed at the bottom of the crushing tank 3, and a guard plate 8 for protecting the heating wire 7 is covered on the outside of the crushing tank 3. A screen 6 for intercepting large particles of sample core to prevent damage to the heating wire 7 is provided inside the crushing tank 3 and above the guard plate 8. At the same time, short plates are welded at both ends of the inner wall of the crushing tank 3 and pinned to the screen 6 for easy later cleaning. An air nozzle 9 is installed at the port of the crushing tank 3 to extract the oil in the core by heating the inside of the crushing tank 3.

[0044] exist Figure 5In the embodiment, a driver 14 is installed inside the equipment box 1, and a belt 13 is sleeved on the driver 14. A rotating shaft 12 is connected to the outer wall of the equipment box 1 near the crushing tank 3, and the other end of the belt 13 is sleeved on the rotating shaft 12. The rotating shaft 12 is connected to one end of the bracket 2, and the other end of the bracket 2 is connected to the handwheel 4. An air pump 15 is also installed in the equipment box 1, and the input end of the air pump 15 is connected to the collecting bottle 11. An air inlet pipe and a pressure gauge 10 are installed at the end of the collecting bottle 11, and the air inlet pipe is connected to the air nozzle 9 through an external pipe. Since oil shale usually contains gaseous hydrocarbons, The concentration detection of gaseous hydrocarbons is also one of the evaluation criteria for the recoverability of shale oil. The sample core is crushed by a centrifugal crushing device. On the one hand, the gas in the sample core can be completely released, and on the other hand, the extraction rate can be improved when the oil is extracted in the later stage. The specific method is: steel balls and other materials that can hit the sample core are added to the crushing tank 3, and the bracket 2 connected to the crushing tank 3 is driven to rotate by the driver 14, belt 13 and shaft 12. In the initial stage, a semi-circular reciprocating motion is performed to make the steel balls hit the sample core to complete the crushing. In the later stage, a unidirectional circular rotation is performed to use centrifugal force to promote the rapid precipitation of gas.

[0045] A shale oil reservoir oil content evaluation system includes the following steps:

[0046] Use the exploration drill bit to drill out the mine and obtain the sample core. At this time, the exploration drill bit remains stationary to form a side protection;

[0047] Extraction of ore cores using abrasive drill bits;

[0048] Grouting is used to seal the mine, mainly to prevent oil from seeping into the area around the mine and causing kerogen precipitation in the oil shale at other exploration sites;

[0049] The ore core is centrifugally crushed using the crushing tank 3;

[0050] Use the air pump 15 to evacuate the collecting bottle 11, connect it to the air inlet 9 through an external pipe, open the collecting bottle 11 and suck out the gas inside the crushing tank 3;

[0051] The crushing tank 3 is heated by a heating wire;

[0052] Petroleum is obtained by distillation;

[0053] Weigh oil, slag, and concrete blocks and measure gas concentrations.

[0054] The gas content per unit mass in the rock sample is calculated based on the fixed capacity of the crushing tank 3 and the gas concentration, and the ratio of the gas content per unit mass to the oil content per unit mass is determined; and the ratio is projected onto a reservoir oil and gas evaluation chart to determine the fluidity and recoverability of the shale oil in the formation represented by the rock sample.

[0055] The above content is a further detailed description of the present invention in conjunction with specific implementation methods. It cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as falling within the scope of protection determined by the claims submitted for the present invention.

Claims

1. A shale oil reservoir oil content evaluation system, comprising a drilling unit, a coring unit, a grouting unit, and a detection unit, characterized in that: The drilling unit is used to drill the target area using an exploration drill bit to obtain a core sample of the oil shale containing kerogen; Coring unit: Use a small grinding drill bit to extend into the exploration drill bit to crush and extract the core sample; Grouting unit: When the exploration drill bit reaches the specified depth, concrete is first injected into the bottom of the borehole through the grouting equipment, thereby sealing the bottom of the mine with concrete blocks to prevent crude oil from rising and kerogen in the core sample from penetrating. When the core sample is completely extracted, the mine is quickly grouting, and the exploration drill bit is lifted during grouting. The grouting unit uses C30 concrete for pouring. The entire grouting unit is divided into two parts. The first part is grouting after the exploration drill bit reaches the predetermined depth. The second grouting is carried out after the core is extracted. The extracted concrete blocks are compared with the core quality. Detection unit: After the ore core is crushed, kerogen, slag and natural gas are obtained. The kerogen and slag are weighed separately and the natural gas concentration is tested. The concrete block is then extracted and weighed. The porosity of the shale is obtained by comparing the weight of the concrete block and the weight of the ore core, and the oil content in the pores is obtained based on the kerogen.

2. The shale oil reservoir oil content evaluation system according to claim 1, characterized in that: The exploration drill bit used in the drilling unit is a hollow drill bit, and the exploration drill bit is provided with wall holes to facilitate grouting and sealing of the well bottom. The outer diameter of the grinding drill bit used in the coring unit is smaller than the inner diameter of the exploration drill bit.

3. The shale oil reservoir oil content evaluation system according to claim 1, characterized in that: The detection unit includes two units: extraction and weighing. The extraction unit includes crushing the ore core and collecting the gas in the ore core, and the weighing unit includes weighing the extracted material and slag while weighing the concrete blocks in the mine.

4. The shale oil reservoir oil content evaluation system according to claim 1, characterized in that: The extraction unit in the detection unit requires a centrifugal crushing device for crushing the ore core. The centrifugal crushing device includes a crushing tank (3) and an equipment box (1). A fixing frame (5) is integrally connected to the equipment box (1). A bracket (2) is rotatably connected to the fixing frame (5). The crushing tank (3) is fixedly connected to the bracket (2).

5. The shale oil reservoir oil content evaluation system according to claim 4, characterized in that: A heating wire (7) is installed at the bottom of the crushing tank (3), and a protective plate (8) is covered on the outside of the heating wire (7). A screen (6) is provided inside the crushing tank (3) and above the protective plate (8). Short plates are welded at both ends of the inner wall of the crushing tank (3) and pin-connected to the screen (6). An air nozzle (9) is installed at the port of the crushing tank (3).

6. The shale oil reservoir oil content evaluation system according to claim 4, characterized in that: A driver (14) is installed inside the equipment box (1), and a belt (13) is sleeved on the driver (14). A rotating shaft (12) is connected to the outer wall of the equipment box (1) on the side close to the crushing tank (3), and the other end of the belt (13) is sleeved on the rotating shaft (12). The rotating shaft (12) is connected to one end of the bracket (2), and the other end of the bracket (2) is connected to a handwheel (4).

7. The shale oil reservoir oil content evaluation system according to claim 4, characterized in that: The equipment box (1) is also equipped with an air pump (15), and the input end of the air pump (15) is connected to a collecting bottle (11). An air inlet pipe and a pressure gauge (10) are installed at the end of the collecting bottle (11), and the air inlet pipe is connected to the air nozzle (9) through an external pipe.

8. The shale oil reservoir oil content evaluation system according to claim 1, characterized in that: The steps include: Drilling out the mine using an exploration drill bit; Extraction of ore cores using abrasive drill bits; Grouting of mine shafts; Centrifugal crushing of the ore core is performed using a crushing tank (3); The collecting bottle (11) is vacuumed by using an air pump (15), and the collecting bottle (11) is connected to the air inlet nozzle (9) by using an external pipe. The collecting bottle (11) is opened to suck out the gas inside the crushing tank (3); Heating the crushing tank (3) using a heating wire; Petroleum is obtained by distillation; Weigh oil, slag, and concrete blocks and measure gas concentrations.

9. The shale oil reservoir oil content evaluation system according to claim 8, characterized in that: The gas content per unit mass in the rock sample is calculated based on the fixed capacity of the crushing tank (3) and the gas concentration, and the ratio of the gas content per unit mass to the oil content per unit mass is determined; and the ratio is projected onto a reservoir oil and gas evaluation chart to determine the fluidity and recoverability of the shale oil in the formation represented by the rock sample.

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