CN110566177A

CN110566177A - Well spacing method for industrial drilling

Info

Publication number: CN110566177A
Application number: CN201910780022.7A
Authority: CN
Inventors: 张卫东; 周晨; 陈志勇; 薄和秋; 刘全江; 王富华
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2019-08-22
Filing date: 2019-08-22
Publication date: 2019-12-13

Abstract

The invention provides a well arrangement method for industrial drilling, which adopts the following technical scheme: firstly, a target block to be mined is subjected to partition design on the basis of comprehensive geological survey, and the area, the position and the number of drilled wells are formulated. Secondly, two well sites which are separated by 100-400 meters in the direction parallel to the horizontal section and 300-600 meters in the direction vertical to the horizontal section are arranged in each planned drilling area to form a matching group. 3-5 well positions with the spacing distance of 6-15 meters are arranged in each well site, and each well position is designed into a horizontal well. The horizontal section of the horizontal well in one well field extends towards the direction of the other well field of the matching group, so that the comprehensive coverage of the oil and gas reservoir below each well field is realized, and the effective utilization rate of resources in the process of exploitation is improved.

Description

Well spacing method for industrial drilling

Technical Field

The invention relates to the field of oil and gas reservoir development, in particular to unconventional oil and gas reservoir development of shale gas and the like, and particularly relates to a well arrangement method for industrial drilling, which is adopted for improving the resource utilization rate and reducing the resource waste.

Background

Along with the reduction of international oil prices, development cost of oil and gas reservoirs needs to be gradually reduced, and particularly, cost reduction is urgently needed for the development of unconventional oil and gas reservoirs with severe mining environments, low permeability of the oil and gas reservoirs and the like. In the process of developing the oil and gas reservoir, factory operation is a novel oil and gas reservoir exploitation method which is proposed in recent years, and relates to the stages of drilling, well cementing and completion, fracturing, exploitation and the like, so that the construction time can be obviously shortened, the development cost of the oil and gas reservoir can be effectively reduced, and the cost reduction and the efficiency improvement are more obvious particularly in the development of unconventional energy.

In the factory drilling process, the well arrangement mode is an important part in the construction design. In the well arrangement mode, the oil and gas reservoir below a drilling well site in the exploitation process is often in a place where the oil and gas reservoir cannot be exploited, and the area is large, so that the effective recovery rate is reduced. If the drilling construction of the vertical well or the directional well is separately carried out for exploiting the oil and gas reservoir resources below the well site, the cost is high and the drilling construction is not laid out. Therefore, a well placement method is needed to solve the problem that the resources of the oil and gas reservoir below the well site cannot be used in the industrial drilling.

Disclosure of Invention

in view of the defects existing when the conventional well spacing mode is applied to industrial drilling, the invention provides a well spacing method for industrial drilling. The method can effectively exploit resources of the oil and gas reservoir below a well site on the premise of easier construction and cost reduction, and realizes more effective coverage of the drilling well pattern on the oil and gas reservoir, thereby improving the effective recovery ratio of resources. In order to achieve the purpose, the invention provides a well arrangement method for industrial drilling, which adopts the following technical scheme:

A well arrangement method for industrial drilling comprises the steps of firstly carrying out partition design on a target block to be mined on the basis of comprehensive geological survey, and formulating a scheme of drilling area positions and quantity. And secondly, in each manufactured well area, two well sites are arranged at the central position thereof to form a matched group, and the two well sites are separated by a certain distance in the transverse direction and the longitudinal direction (the distance in the direction parallel to the horizontal section is 100-400 meters, and the distance in the direction vertical to the horizontal section is 300-600 meters), wherein the distance is determined according to the build rate of the well track and the distance between the horizontal sections of the horizontal well. Then, a plurality of well positions (3-5) are arranged in each well site, the number of the well positions is not more than 5 in general in consideration of the length of a well hole and the construction difficulty, the well positions are separated by a certain distance, and the distance meets the anti-collision requirement according to the requirements of the existing anti-collision process technology. And each well site is drilled into a horizontal well, and in two well sites in one drilling area, the horizontal section of the horizontal well in one well site extends towards the other well site, namely the horizontal sections of the horizontal wells in the two well sites of the matched group extend in opposite directions. The horizontal sections of the horizontal wells in each well field are consistent and parallel in extension direction, and the horizontal sections are longer in extension distance, so that the purposes of reducing the number of drilled wells and improving the effective utilization rate of resources are achieved.

In summary, the invention has the following beneficial effects: aiming at industrial drilling, the well distribution mode has small drilling construction difficulty and low cost. The well arrangement method can meet the requirements of industrial drilling, can avoid the problem that resources of the oil and gas reservoir below a well field cannot be used, effectively improves the utilization rate of the resources of the oil and gas reservoir, and reduces resource waste.

Drawings

FIG. 1 is a diagram of a factory drill site, wellsite placement, according to one embodiment of the present invention.

FIG. 2 is a three-dimensional view of a factory-drilled wellbore trajectory according to one embodiment performed in accordance with the present invention.

FIG. 3 is a top plan view of a factory drilled wellbore trajectory according to one embodiment performed in accordance with the present invention.

FIG. 4 is an elevation view of a factory drilled wellbore trajectory according to one embodiment performed in accordance with the present invention.

Detailed Description

The following detailed description of specific embodiments of the present invention is made with reference to the accompanying drawings and examples.

Firstly, according to the previous geological survey research, a reasonable number of drilling exploitation areas are designed in a target oil and gas reservoir area. The well site is prepared and leveled prior to drilling and two drilling sites are positioned in the area, shown as well site 1 and well site 2 in FIG. 1. Each well site is provided with 4 horizontal wells, wherein the well site 1 is provided with a well 1, a well 2, a well 3 and a well 4, and the well site 2 is provided with a well 5, a well 6, a well 7 and a well 8. The distance between the wellheads of all the wellsites in the same wellsite is 10 meters. The horizontal sections of well 1, well 2, well 3 and well 4 in well site 1 extend in the direction of well site 2 over a distance of 1000 meters. The horizontal sections of wells 5, 6, 7 and 8 at well site 2 extend in the direction of well site 1 over a distance of 1000 meters. The horizontal segments are parallel to each other and the distance between them is set to 400 meters.

By the well arrangement method, 4 horizontal wells in the well site 1 can extend to the position under the well site 2, and the wells 1 and 8 in the well sites 1 and 2 are in the same straight line, so that oil and gas reservoir resources under the well sites can be effectively exploited, the condition that the oil and gas reservoir cannot be used is avoided, and the recovery ratio of the oil and gas reservoir is improved.

The distance and location of the wellsites may vary depending on the nature of the reservoir, the drilling environment at the surface, etc., and in one embodiment, as shown in FIG. 1, wellsite 1 and wellsite 2 are spaced apart by 300 meters, which may reduce the length of the horizontal segments and increase the number of wellsites if horizontal drilling is difficult due to the greater reservoir depth. So that the oil and gas reservoir can be effectively developed at lower cost.

In one embodiment, well 2 employs a straight-plus-steady-plus-flat five-section wellbore profile and wells 1, 3 and 4 employ a straight-plus-steady-twisted-flat five-section wellbore profile in accordance with the present invention, as shown in fig. 2. Effective collision prevention between the boreholes can be realized by using the borehole profile. And at a deflecting position, deflecting can be completed by using a deflecting rate of 9 degrees/30 m, and if well site adjustment is carried out and the distance is increased, the deflecting rate can be further reduced, so that the construction difficulty is lower.

In one embodiment, as shown in FIG. 1, the number of well sites at a single wellsite is 4, and if the reservoir is hard and drilling is difficult, the number of well sites at a single wellsite can be adjusted to 3.

In one embodiment, as shown in fig. 1, the wellhead distance of each well location is 10 meters, considering that the prior drilling technology can easily realize inter-well collision prevention, if the collision prevention technology of the drilling team is mature and has rich experience, the distance between the wellheads can be properly reduced to 8 meters or less.

In one embodiment, as shown in FIG. 1, it is necessary to place fractures for each horizontal segment to perform the fracturing operation. The interval between the horizontal well sections is 400 meters, and considering that the existing fracturing technology can fracture the crack to 180 meters, the crack of the two horizontal sections can fully cover the oil and gas reservoir, so that the recovery ratio of the oil and gas reservoir is improved. If the later period of exploitation is reached, the well arrangement mode can also carry out water injection development with high efficiency, and the effect is obvious theoretically.

The well site and well position arrangement designed by the well arrangement method realizes comprehensive coverage of underground resources, greatly improves the effective utilization rate of oil and gas reservoir resources, and is particularly suitable for unconventional oil and gas reservoirs with compactness.

Claims

1. A well spacing method for industrial drilling is characterized by comprising the following steps:

Two well sites are arranged in each well drilling area at intervals (100-400 meters apart in the direction parallel to the horizontal section and 300-600 meters apart in the direction perpendicular to the horizontal section) to form a matched group, horizontal wells are arranged in the two well sites, and the horizontal section of the horizontal well in one well site extends towards the other well site for a longer distance, so that complete coverage in the well drilling area is realized.

2. The well placement method for industrial drilling according to claim 1, wherein in each drilling area where the target block is placed, two well sites matched with each other are placed at a distance (100-400 m apart in a direction parallel to the horizontal section and 300-600 m apart in a direction perpendicular to the horizontal section) to form a group. 3-5 well positions with the spacing distance of 6-15 meters are arranged in each well site, and the distance can meet the anti-collision requirement of the prior construction technology. The well pattern of each well site is a large-displacement horizontal well, and the horizontal section of the horizontal well in one well site extends towards the direction of the other well site, so that the horizontal wells arranged by two mutually matched well sites can completely cover the drilling area.

3. The well spacing method for industrial drilling according to claim 2, wherein the projections of the horizontal wells arranged in the two wellsites in the vertical plane are parallel in the vertical well section, the steady inclined section is V-shaped, and the horizontal sections are straight lines.

4. The method of any one of claims 1 to 3, wherein the kick-off points of each adjacent well at each well site are offset by at least 30m above each other to prevent cross-over between the wells and magnetic interference.

5. the well control system of any one of claims 1-4, wherein each wellsite horizontal well has a five-stage control of straight-augmented-steady-augmented-flat for one well and straight-augmented-steady-twisted-flat for the other wells.

6. The well spacing method for industrial drilling according to claim 2, wherein the distance between horizontal wells drilled on the same straight line at two matched well sites is 100-200 m.

7. The method of claim 2, wherein the pre-target displacement of each horizontal well is greater than the distance between corresponding horizontal wells drilled at two matching well sites.

8. The well spacing method for industrial drilling according to claim 2, wherein the wellbore trajectory of the horizontal well has a slope of 6 °/30m to 9 °/30m in a deviated section.

9. The well spacing method for industrial drilling according to claim 2, wherein the horizontal well has a horizontal section length of 500-2000 m, and the horizontal wells in each well site are separated by a distance of 400-600 m.