CN-121993033-A - Real-time determination method for coal gangue in horizontal section of coalbed methane

CN121993033ACN 121993033 ACN121993033 ACN 121993033ACN-121993033-A

Abstract

The invention belongs to the field of coal gangue exploitation, and relates to a real-time judgment method for coal gangue at a horizontal section of coal bed methane, which comprises the steps of 100, lowering a horizontal section drilling tool to obtain azimuth gamma data of the horizontal section of the coal bed methane, 200, generating an azimuth gamma curve according to the azimuth gamma data and corresponding well depth data, 300, observing inflection points of the azimuth gamma curve, prejudging the coal gangue when drilling is carried out, 400, judging the coal gangue when the torque is observed at a wellhead, 500, determining that a drilling track is positioned in the horizontal section of the coal bed methane, adjusting the drilling track, and continuing drilling, 600, and repeating 300-500. And the horizontal section drilling tool is used for drilling in the target coal layer, the azimuth gamma detection tool in the horizontal section drilling tool is used for detecting whether the drilling meets coal gangue in real time, and the drilling parameters are timely adjusted after the drilling meets the coal gangue is judged, so that the underground collapse degree is reduced, and the safe drilling of the horizontal section is ensured.

Inventors

NIU TAO
ZHU MINRONG
LIU KEQIANG
CHEN CAIZHENG
YANG BIN
LIANG HONGWEI
JIANG SHENGHUI
DU SONGTAO
HAN CHAOHUI
LI XINDI

Assignees

中国石油天然气集团有限公司
中国石油集团川庆钻探工程有限公司

Dates

Publication Date: 20260508
Application Date: 20241107

Claims (8)

1. The method for judging the coal gangue in the horizontal section of the coalbed methane in real time is characterized by comprising the following steps of: step 100, a horizontal section drilling tool is lowered, and azimuth gamma data of a coal bed gas horizontal section are obtained; step 200, generating an azimuth gamma curve according to the azimuth gamma data and the corresponding well depth data; Step 300, observing inflection points of the azimuth gamma curve, and pre-judging coal gangue; Step 400, judging that the drill meets coal gangue when the torque and the drill are observed at a wellhead; step 500, determining that the drilling track is positioned in the coalbed methane horizontal section, adjusting the drilling track, and continuing drilling; step 600, repeat steps 300-500.
2. The method for judging coal gangue in horizontal section of coal bed gas in real time according to claim 1, wherein the horizontal section drilling tool consists of a drill bit, a single-bending screw, a short section, a non-magnetic drill collar and a drill rod which are connected in sequence; the non-magnetic drill collar is provided with an azimuth gamma detection tool for acquiring azimuth gamma data.
3. The method for determining the coal gangue in the horizontal section of the coalbed methane in real time according to claim 2, wherein the horizontal section drilling tool drills through a target coalbed of the horizontal section of the coalbed methane, and the target coalbed is mixed with the coal gangue; the upper part of the target coal seam is a target coal seam upper interface, and the top layer of the target coal seam upper interface is a roof; the lower part of the target coal seam is a target coal seam lower interface, and the bottom layer of the target coal seam lower interface is a bottom plate.
4. The method of claim 3, wherein the step 300 of observing the inflection point of the azimuth gamma curve, pre-judging drilling coal gangue comprises: And observing the inflection point of the azimuth gamma curve, if the inflection point of the azimuth gamma curve is 1-2m away from the upper interface of the target coal seam or the lower interface of the target coal seam, pre-judging that drilling meets coal gangue, and simultaneously observing the change of torque and drilling time at a wellhead.
5. The method of claim 1 or 4, wherein step 400, when observing torque and drilling at a wellhead, determines that drilling meets gangue, comprises: when the torque and the drilling are observed at the wellhead, if the torque is increased and the drilling time is prolonged, the length is adjusted to be increased by 2-8m so that the torque and the drilling time are normal, the drilling fluid circulates normally, and the drilling is judged to meet the coal gangue.
6. The method of claim 3 or 4, wherein determining that the drilling path is located in the coalbed methane horizontal segment in step 500 means: And in the drilling process of the horizontal section drilling tool, if the torque of a wellhead is increased and the drilling time is prolonged, and meanwhile, the inflection point of the azimuth gamma curve is 2-3m away from the upper interface of the target coal seam or the lower interface of the target coal seam, the drilling tool is pre-judged to meet coal gangue, and the drilling track is determined to be positioned in the coal seam gas horizontal section.
7. A method for determining coal gangue in a horizontal section of coal bed methane in real time as claimed in claim 3, further comprising: And if the drilling track is judged not to be in the coalbed methane horizontal section, reducing the rotation speed of the wellhead, and performing short tripping operation to keep the well wall stable.
8. The method of claim 7, wherein the drill path is not within the horizontal section of coal seam gas is characterized by the drill bit of the horizontal section drilling tool drilling the target coal seam; the method for judging that the drilling track is not in the coalbed methane horizontal section comprises the following steps: If the upper gamma value of the azimuth gamma curve is firstly increased along with the increase of the well depth, the lower gamma value is then increased, and then the upper gamma value and the lower gamma value are overlapped together and are higher than the average gamma value, the drill bit of the horizontal section drilling tool is drilled out from a top plate, and the drilling track is further indicated not to be in the coal bed gas horizontal section; And if the lower gamma value of the azimuth gamma curve is firstly increased along with the increase of the well depth, the upper gamma value is then increased, and then the upper gamma value and the lower gamma value are overlapped, so that the drill bit of the horizontal section drilling tool is drilled out from the bottom plate, and the drilling track is not in the coal bed gas horizontal section.

Description

Real-time determination method for coal gangue in horizontal section of coalbed methane Technical Field The invention belongs to the field of coal gangue exploitation, and particularly relates to a real-time judgment method for coal gangue in a horizontal section of coal bed gas. Background The depth of extraction of coalbed methane is typically above 300 meters underground. The coalbed methane horizontal well has the characteristics of small well site occupation area, large single well control storage surface, large single well gas production capacity and the like. However, the horizontal well has the construction difficulties of difficult safe window entering, lower drilling meeting rate, high collapse and blockage prevention risk and the like in the drilling construction process. At present, the position of a drill bit in a coal seam is determined by detecting the gamma value of the stratum in a specific direction in real time by using an azimuth gamma detection tool, so that the drill bit is prevented from drilling the coal seam, the drilling meeting rate of a horizontal coal seam can be improved, the judging efficiency of the horizontal section coal seam drilling meeting coal gangue is low, the well hole collapse is easy to occur, and the safe and rapid drilling of the long horizontal section of the coal seam gas is always plagued. Disclosure of Invention The invention aims to provide a real-time judging method for coal gangue in a horizontal section of coal bed gas, so as to overcome the technical defects. In order to solve the technical problems, the invention provides a method for judging coal gangue in a horizontal section of coal bed gas in real time, which comprises the following steps: step 100, a horizontal section drilling tool is lowered, and azimuth gamma data of a coal bed gas horizontal section are obtained; step 200, generating an azimuth gamma curve according to the azimuth gamma data and the corresponding well depth data; Step 300, observing inflection points of the azimuth gamma curve, and pre-judging coal gangue; Step 400, judging that the drill meets coal gangue when the torque and the drill are observed at a wellhead; step 500, determining that the drilling track is positioned in the coalbed methane horizontal section, adjusting the drilling track, and continuing drilling; step 600, repeat steps 300-500. According to the real-time judging method of the coal gangue of the horizontal section of the coalbed methane, the horizontal section drilling tool consists of a drill bit, a single-bending screw, a short section, a non-magnetic drill collar and a drill rod which are connected in sequence; the non-magnetic drill collar is provided with an azimuth gamma detection tool for acquiring azimuth gamma data. According to the real-time judging method of the coal gangue in the horizontal section of the coal bed gas, the horizontal section drilling tool drills through the target coal bed of the horizontal section of the coal bed gas, and the target coal bed is mixed with the coal gangue; the upper part of the target coal seam is a target coal seam upper interface, and the top layer of the target coal seam upper interface is a roof; the lower part of the target coal seam is a target coal seam lower interface, and the bottom layer of the target coal seam lower interface is a bottom plate. According to the real-time determination method of the coal gangue in the horizontal section of the coalbed methane, the step 300 is to observe the inflection point of the azimuth gamma curve, and the pre-determination method of the coal gangue comprises the following steps: And observing the inflection point of the azimuth gamma curve, if the inflection point of the azimuth gamma curve is 1-2m away from the upper interface of the target coal seam or the lower interface of the target coal seam, pre-judging that drilling meets coal gangue, and simultaneously observing the change of torque and drilling time at a wellhead. According to the method for judging the coal gangue in the horizontal section of the coalbed methane in real time, the step 400 judges that the drilling meets the coal gangue when the torque is observed at a wellhead and the drilling is performed, and the method comprises the following steps: when the torque and the drilling are observed at the wellhead, if the torque is increased and the drilling time is prolonged, the length is adjusted to be increased by 2-8m so that the torque and the drilling time are normal, the drilling fluid circulates normally, and the drilling is judged to meet the coal gangue. According to the method for judging the coal gangue in the horizontal section of the coalbed methane in real time, the step 500 is to determine that the drilling track is positioned in the horizontal section of the coalbed methane, which means that: And in the drilling process of the horizontal section drilling tool, if the torque of a wellhead is increased and the drilling time is prolonged, an