阅读说明：本技术 一种清除长水平段岩屑床的方法 (Method for removing long horizontal section detritus bed ) 是由 王清臣 张建卿 胡祖彪 谭学斌 李录科 王伟良 李德波 韩成福 侍德益 柳伟荣 于 2020-07-06 设计创作，主要内容包括：本发明属于石油钻井技术领域,具体涉及一种清除长水平段岩屑床的方法,具体步骤如下：1)钻进时,在水平段井内钻具的钻杆上套接多个圆柱；2)钻具每钻进规定距离,将钻具起出水平段井,同时转动钻具和圆柱,钻具进行倒划眼使井壁钻屑运移到地面；3)步骤2)钻具每钻进设定距离,用洗井液清洗一次井筒；解决了现有超长水平段井中钻进过程中易形成岩屑床以及岩屑床难以消除,增大了钻具和井壁的摩擦面积和摩擦系数,导致钻具摩阻较大,完井风险大的问题,具有水力和机械双作用阻止岩屑床的形成,并能够更好地清除和破坏已形成的岩屑床。(The invention belongs to the technical field of petroleum drilling, and particularly relates to a method for removing a long horizontal section detritus bed, which comprises the following steps: 1) during drilling, a plurality of cylinders are sleeved on a drill rod of a drilling tool in a horizontal section of a well; 2) when the drilling tool drills a specified distance, the drilling tool is lifted out of the horizontal section well, the drilling tool and the cylinder are rotated at the same time, and the drilling tool performs back reaming to enable drill cuttings on the well wall to be moved to the ground; 3) step 2), cleaning a shaft once by using a well flushing fluid every time the drilling tool drills a set distance; the problems that in the existing drilling process of an ultra-long horizontal section well, a detritus bed is easy to form and is difficult to eliminate, the friction area and the friction coefficient of a drilling tool and a well wall are increased, the friction resistance of the drilling tool is large, and the well completion risk is high are solved, the formation of the detritus bed is prevented by the aid of the hydraulic and mechanical double functions, and the formed detritus bed can be better removed and damaged.)

1. A method of removing a bed of cuttings from a long horizontal section, comprising: the method comprises the following specific steps:

1) during drilling, a plurality of cylinders (2) are sleeved on a drill rod (1) of a drilling tool in a horizontal section well;

2) when the drilling tool drills a specified distance, the drilling tool is lifted out of the horizontal section well, the pump is started to rotate the drilling tool and the column (2), and the drilling tool performs back reaming to enable drill cuttings in the well wall to be moved to the ground;

3) and 2) cleaning the shaft once by using the well flushing fluid every time the drilling tool drills for a set distance.

2. The method of removing a bed of long horizontal cuttings of rock defined in claim 1, wherein: the outer diameter of the cylinder (2) is 98.6-99% of the borehole diameter.

3. The method of removing a bed of long horizontal cuttings of rock defined in claim 1, wherein: the length of the cylinder (2) is 50-100 cm.

4. The method of removing a bed of long horizontal cuttings of rock defined in claim 1, wherein: the outer surface of the cylinder (2) is provided with a plurality of bulges (3) which are uniformly distributed.

5. The method of removing a bed of long horizontal cuttings of rock defined in claim 1, wherein: the distance between two adjacent cylinders (2) is 300-500 m.

6. The method of removing a bed of long horizontal cuttings of rock defined in claim 1, wherein: the specified distance of the step 2) is 500-1000 meters.

7. The method of removing a bed of long horizontal cuttings of rock defined in claim 1, wherein: and 2) the low shear rate shear force of the drilling fluid in the horizontal section well in the step 2) is greater than 4 Pa.

8. The method of removing a bed of long horizontal cuttings of rock defined in claim 1, wherein: the set distance of the step 3) is 500 meters, and the dosage of the well-flushing liquid is 80-120m³。

9. The method of removing a bed of long horizontal cuttings of rock defined in claim 1, wherein: the Reynolds number of the well-flushing fluid is larger than 2100.

Technical Field

The invention belongs to the technical field of petroleum drilling, and particularly relates to a method for removing a long horizontal section detritus bed.

Background

During the drilling process of the horizontal section, drilling fluid continuously carries drill cuttings to the ground so as to ensure the cleanness of a shaft and the normal drilling construction. However, due to the action of gravity, the drill cuttings in the horizontal section are easy to sink and deposit on the lower well wall to form a rock cuttings bed, so that the normal drilling construction is hindered. The successful construction of a well with an ultra-long horizontal section (the horizontal section exceeds 3000 meters) is a key factor to prevent the formation of a drilling cutting bed or eliminate the drilling cutting bed in time.

No special detritus bed eliminating process is adopted in construction of two 3000-meter horizontal section wells in Changqing oil fields in 2018, the formed detritus bed is serious, the friction area and the friction coefficient of a drilling tool and a well wall are increased, the friction resistance of the drilling tool is large, the downward falling friction resistance of the drilling tool reaches 60-90 tons when drilling is finished, and the well completion risk is very high.

Disclosure of Invention

The invention provides a method for removing a long horizontal section rock debris bed, and aims to solve the problems that in the prior art, the rock debris bed is easy to form and difficult to remove in the drilling process of an ultra-long horizontal section well, the friction area and the friction coefficient of a drilling tool and a well wall are increased, the friction resistance of the drilling tool is larger, and the well completion risk is high.

Therefore, the invention provides a method for removing a long horizontal section detritus bed, which comprises the following specific steps:

1) during drilling, a plurality of cylinders are sleeved on a drill rod of a drilling tool in a horizontal section of a well;

2) when the drilling tool drills a specified distance, the drilling tool is lifted out of the horizontal section well, the drilling tool and the cylinder are rotated at the same time, and the drilling tool performs back reaming to enable drill cuttings on the well wall to be moved to the ground;

3) and 2) cleaning the shaft once by using the well flushing fluid every time the drilling tool drills for a set distance.

The outer diameter of the cylinder is 98.6-99% of the borehole diameter.

The length of the cylinder is 50-100 cm.

The outer surface of the cylinder is provided with a plurality of bulges which are uniformly distributed.

The distance between the two adjacent cylinders is 300-500 m.

The specified distance of the step 2) is 500-1000 meters.

And 2) the low shear rate shear force of the drilling fluid in the horizontal section well in the step 2) is greater than 4 Pa.

The set distance of the step 3) is 500 meters, and the dosage of the well-flushing liquid is 80-120m 3.

The Reynolds number of the well-flushing fluid is larger than 2100.

The invention has the beneficial effects that: according to the method for removing the detritus bed in the long horizontal section, during drilling, a plurality of cylinders are sleeved on a drill rod of a drilling tool in a horizontal section well, the outer diameter of each cylinder is 98.6-99% of the diameter of a well hole, the outer diameter of each cylinder is larger than the outer diameter of the drill rod in the well hole, so that the cylinders cannot be blocked when rotating in the horizontal well, drill cuttings formed by the wall of the well hole are stirred to the maximum extent, the length of each cylinder is 50-100cm, bulges are distributed on the surface of each cylinder, the drilling tool and the rigid cylinders can be rotated by starting a pump, better stirring and removing effects can be achieved on the drill cuttings formed by the wall of the well hole, one cylinder is arranged at intervals of 300 meters, the drill cuttings which are not collected on the wall of the well hole; when the drilling is carried out for a specified distance (500-; the low shear rate shear force of the horizontal section drilling fluid is greater than 4Pa, so that the drilling fluid not only has better sand carrying performance in a pump-on circulation state, but also has better rock debris suspension capacity in a pump-off state, and drill cuttings are difficult to sink to the well wall; every drilling time the set distance (500 m) is used, 80-120m³The well-flushing liquid cleans the primary shaft, and the Reynolds number of the cleaning liquid is larger than 2100, so that the well-flushing liquid is in a turbulent state when the shaft is cleaned, and the lower well wall debris bed can be better damaged; the method has the advantages of strong process operability, less equipment requirement, good effect of eliminating the detritus bed in the drilling process of the overlong horizontal section well, reduction of the friction area and the friction coefficient of the drilling tool and the well wall, reduction of the friction resistance of the drilling tool and guarantee of the underground safety.

Drawings

The present invention will be described in further detail below with reference to the accompanying drawings.

FIG. 1 is a schematic view of the structural connection of the drill pipe and the cylinder of a horizontal section of a borehole drilling tool;

FIG. 2 is a schematic view of the lowering friction of the drilling tool in the horizontal section of the three long horizontal section well.

Description of reference numerals: 1. a drill stem; 2. a cylinder; 3. a protrusion; 4. HuaH 16-1; 5. ning H7-2; 6. HuaH 50-7.

Detailed Description