Directional well drilling technology paper I
Analysis of drilling trajectory control technology for directional wells
Abstract: The key technology of directional drilling is well trajectory control technology. Based on the analysis of the optimal design technology of directional well trajectory profile, the control technology of drilling well trajectory is discussed.
[Keywords] Directional well; Drilling trajectory; key technology
China Library Classification Number: TG998 Document Identification Number: A Document Number:1009-914x (2015) 08-0056-01.
With the increase of exploration and development of oil and gas resources in China, more and more attention has been paid to the exploration and development of complex oil and gas reservoirs, such as ground obstacles, complex geological conditions and structural obstacles such as faults, and drilling accidents requiring sidetracking. These oil and gas reservoirs generally need directional drilling technology to develop, so as to increase the exposed area of oil and gas reservoirs, improve oil and gas recovery and reduce drilling costs. However, it is difficult to control the well trajectory of directional well drilling, so it is necessary to optimize the well trajectory design, and adopt different drilling trajectory control technologies in vertical section, inclined section and stable inclined section to effectively ensure the well trajectory of directional well. Exploring these technical measures has become the key to improve the drilling level of directional wells.
1. Scientifically design the trajectory and orbit of directional wells.
1, optimization design technology of directional well trajectory
Wellbore trajectory profile design is the basis of directional drilling construction. Only by constantly optimizing and perfecting the well trajectory design and ensuring the scientificity and rationality of the well trajectory design can we ensure the expected goal of directional drilling. In the optimization design of directional well trajectory profile, we must adhere to certain principles: to achieve the geological goal of directional well drilling. There are many geological objectives of directional well drilling, including crossing multiple oil-bearing strata to improve the exploration and development effect, avoiding geological structures such as faults in strata to realize the effective exploitation of underground remaining oil and gas reservoirs, and realizing the large-scale extension of oil well trajectory in the target layer of oil and gas reservoirs to increase the exposed area of oil and gas reservoirs. At the same time, directional wells can be used to sidetrack oil and gas reservoirs for oil wells that cannot be normally exploited due to accidents during drilling or oil and gas exploitation, and for drilling and exploitation in areas where normal drilling is not possible due to ground obstacles. In order to save the drilling cost, the area occupied by the well site can also be saved by developing directional wells on the cluster platform. We should take the high-quality and safe drilling construction in colleges and universities as the purpose of on-site construction. When designing the trajectory profile of directional wells, it is necessary to combine the design with the geological characteristics of this area, and choose a position with stable strata and moderate hardness for deflecting. The kick-off point should try to avoid the stratum prone to collapse, shrinkage or leakage and abnormal pressure, and the inclination angle of the kick-off section should be controlled at 15? -45? On the other hand, if the inclination angle is too large, it will increase the construction difficulty and easily lead to drilling accidents, while if the inclination angle is too small, it will lead to unstable drilling orientation and increase the number of adjustments. In addition, in the selection of the build-up rate, we should comprehensively consider the geological conditions of the formation where the oil well is located and the actual build-up rate of drilling tools, and try our best to reduce the build-up rate and shorten the length of the build-up rate section on the premise of meeting the drilling objectives of directional wells, so as to achieve the purpose of rapid drilling. We should try our best to meet the requirements of oil production and completion technology in the later stage. On the premise of meeting the drilling requirements of directional wells, the borehole curvature should be reduced as much as possible, which is convenient for running sucker rod and oil casing in the later period, and at the same time, the eccentric wear between them should be reduced, which is convenient for the later reconstruction of safe oil pump and other underground operations.
2. Design of drilling trajectory for directional wells.
According to the different purposes and uses of fixed drilling, directional wells can be divided into conventional directional wells, cluster wells and extended reach wells for design. The horizontal displacement of conventional directional wells is generally less than 1km, and the vertical depth is less than 3km. Cluster wells can reduce the well site area. The trajectory of extended reach directional well generally adopts catenary trajectory, and the trajectory of borehole adopts high stable dip angle and low build-up rate. What are the profile trajectories of directional wells in China? Straight increase and stability? Three-stage system? Straight up and down? Four sections and? Straight-increasing-stabilizing-decreasing-straight? There are three types of five-section profile, which are optimized according to the different geological characteristics of the local strata in the specific design. The three kinds of well trajectory have their own advantages and disadvantages: the deflection section of the three-section well trajectory is short, which is convenient for design and construction operation, and the three-section well trajectory profile can be used when there are no other special requirements; During the tripping operation of the fourth-level borehole trajectory profile, it is easy to hit the keyway to increase the tripping friction, which is easy to cause sticking accidents and the formation of cuttings bed. It is generally not used and is only used under special circumstances. The trajectory profile of the five-stage borehole is vertical in the target oil and gas reservoir, which is beneficial to the safe operation of the oil recovery pump and the realization of the later oil recovery technology.
Drilling control technology of directional well trajectory profile in the second and third sections
Based on the advantages and disadvantages of three different types of trajectory profiles, three-section and five-section wellbore trajectory profiles are often used in directional drilling design in reality, of which three-section wellbore trajectory profile is the most commonly used. This paper studies the drilling control technology of three-section directional borehole trajectory.
1 and wellbore trajectory control technology in vertical interval
The vertical well trajectory control technology is mainly to prevent deviation and straighten, which is the basis of directional well trajectory control. Due to geological, engineering and borehole enlargement, borehole deviation will occur when drilling in vertical intervals, and geological factors are uncontrollable. Technical measures can be taken in the construction to enlarge the borehole and control the drilling trajectory in the vertical section. The key is to select the combination of eyeful drilling tool and pendulum drilling tool to drill in vertical section. The former can prevent the inclination during drilling and make the centralizer as close as possible to the borehole wall. The working principle of pendulum drilling tool is that it will produce restoring force after exceeding a certain angle, which can correct the well deviation problem. However, it is necessary to ensure proper WOB, because too large WOB will reduce the swinging force, increase the tilting force and hinder the rectification effect.
2. Well trajectory control technology in the deflecting section.
In directional well drilling, the drilling of deflecting section is the key link. Kick-off is the process of making the bit deviate from the vertical line of the wellhead from the designed kick-off point. The key is to make the bit deviate from the vertical line and start oblique drilling. According to the designed borehole trajectory, the build-up slope is calculated by integrating angle of inclination and azimuth deviation, so as to guide the build-up drilling construction. By adding drill collars and other measures, the proportion of sliding drilling and compound drilling is adjusted, so that the bit can drill according to the designed borehole trajectory and guide the completion of the deflecting section.
3. Control technology of borehole trajectory in inclined section of stable well.
After the completion of the oblique section, the drilling construction of the stable section is needed. In the process of drilling in the stable section, wireless logging while drilling instrument should be selected to dynamically track the working process of the bit, monitor the actual inclination and azimuth deviation of the bit in real time, and compare it with the design value to ensure that the bit hits the target. In the absence of wireless logging-while-drilling tools, it is necessary to drill through the inclinometer assembly and use single-point and multi-point inclinometers to conduct fixed-point inclinometers to ensure the target in drilling and improve the drilling quality.
Three. conclusion
To sum up, directional well is an effective means to exploit complex oil and gas reservoirs, and conventional oil wells can exploit them. However, in order to successfully realize directional well drilling, it is necessary to design well trajectory profile, select appropriate trajectory type according to geological characteristics, and adopt corresponding well trajectory control technology for different intervals to ensure drilling according to the designed well trajectory and improve the oil and gas resources exploitation effect.
refer to
[1] Wang Huiyun. Analysis of technical difficulties in directional well logging [J]. Development and Economy of Science and Technology Information, 2009( 10).
Lu Gang, Wang Gang, Xing Yude, Sun Zhongguo, Zhang Fangfang. Two Problems in Calculation of Spatial Circular Orbit of Directional Well Drilling [J]. Petroleum Geology and Engineering, 2006(06).
Wang Xuejian. Continuous control drilling technology for shallow directional wells [J]. Petroleum drilling technology, 2004(05).
Cui Jianying, He Changhua. Development of directional well information query system [J]. Digital Chemical Industry, 2005(07).
Directional well drilling technology paper II
Discussion on directional drilling technology of coalbed methane in Shouyang block
This paper introduces the present situation and characteristics of coalbed methane development in Shouyang, and analyzes the application of directional well drilling technology in the construction process, which has a certain guiding role for directional wells in Shouyang block in the future.
Keywords: Shouyang block; Directional well; Oblique section; Inclined stable section
This paper introduces the development status and characteristics of coalbed methane in Shouyang, and analyzes the application of directional drilling technology in the construction process, which has a certain guiding role for the construction of directional wells in Shouyang block.
Keywords: Shouyang block; Directional well; Oblique section; Stable inclined section
China library classification number: P634.5
1. Overview
Shouyang Block is located in the middle of Shanxi Province and at the northern end of Qinshui Basin. It is one of the large coal-bearing basins in China and is rich in coalbed methane resources. According to the data obtained from the parameter wells and directional production wells built by Far East Energy (Bermuda) Co., Ltd. in the south of Qinshui Basin, it shows that this area has a good development prospect.
Shouyang block 1. 1 exploration and development history and present situation
From 65438 to 0995, the United Nations Development Programme (UNDP) conducted an evaluation study on the development of coalbed methane resources in Yangquan mining area (including production area, Pingxi area and Shouyang area) by using the project of "Development of coalbed methane resources in China" funded by the Global Environment Facility and the special scientific research report of "Evaluation of coalbed methane resources in Yangquan mining area" undertaken by xi Branch of the General Institute of Coal Science.
China General Bureau of Coalfield Geology has constructed a number of coalbed methane exploration parameter wells in Han Zhuang minefield 1996 to 1997, and obtained the relevant coal reservoir parameters in this area, and carried out fracturing reconstruction and drainage test on the main coal seam of Well HG6, and obtained a complete set of data on the combined layer drainage of this well. During the period of 1997 ~ 1998, Zhonglian Company constructed 4 coalbed methane production wells in Shouyang block, including exploratory wells 1 well and 3 production test wells, and obtained valuable coal reservoir parameters and production data in this area. 1998, four 2D seismic exploration lines were completed, with a total length of 167km, and rich geological results were obtained. In 2005, Far East Company built three pinnate horizontal wells in this area, of which two wells had a footage of more than 3,000 meters in the coal seam section, and all three wells were in production.
In 2007, Far East Energy (Bermuda) Co., Ltd. thought that the 15# coal seam in this area was very stable and the reservoir parameters were favorable, which was a favorable block for coalbed methane development. It is decided to deploy several directional wells and parameter wells in Zhu Zhen, south extension of Shouyang County, in order to obtain the reservoir parameters such as buried depth and thickness of 15# coal seam in this area.
Geological background of Shouyang 1.2 block
The northern end of Qinshui Basin is located in the west of Taihang Mountain Uplift, the third uplift of Xinhua Xia, the east of Fenhe Graben and the south wing of Yuxian banded structural belt in Yangqu. The overall shape is monoclinic structure with east-west strike and south inclination. The structure in the area is simple, the stratum is gentle, and the dip angle is generally 10? About. During the Yanshan movement and Himalayan movement, the background value of geothermal flow increased due to large-scale magma intrusion. On the basis of the original plutonic metamorphism, the Carboniferous and Permian coal seams in this area are superimposed by regional magmatic thermal metamorphism, which greatly deepens the coalification and forms high metamorphic lean coal, lean coal and a small amount of anthracite in this area.
The strata drilled in this area are Quaternary (Q), Liujiagou Formation of Lower Triassic (T 1l), Shiqianfeng Formation of Upper Permian (P2sh), Upper Shihezi Formation of Upper Permian (P2x), Lower Shihezi Formation of Lower Permian (P 1x) and Shanxi Formation of Lower Permian.
Characteristics of Coal Reservoir in Shouyang 1.3 Block
The main coal-bearing strata are Taiyuan Formation of Upper Carboniferous and Shanxi Formation of Lower Permian, with coal-bearing layers of 10, of which 3#, 9# and 15# are the main coal seams.
3# coal seam: commonly known as Qichi coal, the coal seam in the whole area is 0 ~ 3.78 m thick and relatively stable. The coal seams in the western Shouyang mining area and Yangquan No.3 mining area are thick, while those in other areas are thin or even pointed out. Simple structure, sometimes containing a layer of dirt band, with mudstone, sandy mudstone and siltstone at the top and bottom, and carbonaceous mudstone and fine sandstone locally.
9# coal seam: the thickness of coal seams in the whole region is different, and the coal seams are relatively stable. The structure is simple, the roof and floor are mudstone, sandy mudstone and siltstone, and some are carbonaceous mudstone and fine sandstone.
15# coal seam: the thickness of coal seam is 0.27 ~ 6.48 m, which is the main coal seam for coalbed methane development in Shouyang block. 15# coal contains 1 ~ 3 layers of gangue, with medium structure, K2 limestone on the roof and floor, mudstone and sandy mudstone on the floor, and carbonaceous mudstone and fine sandstone locally.
The coal reservoir in the northern end of Qinshui Basin has a large thickness and a moderate buried depth. The coal has a high degree of thermalization and has entered the peak of gas generation, and the roof and floor of the coal seam are well sealed and have high gas content; The fractures of coal reservoir are developed, and the pores are mainly small holes and micropores, with good permeability. Coal has strong adsorption performance, but its gas saturation is low.
2. Equipment selection
2. 1 rig selection
The depth of directional production wells in Shouyang Block is generally within1000m, and the horizontal section is not more than 500m. According to the existing equipment of our drilling team, TSJ-2000 and GZ-2000 rigs are selected. The lifting and rotating ability of drilling rig can meet the needs of directional production well construction of coalbed methane.
2.2 Equipment configuration
Water pumps: TBW-850 (vertical), 3NB- 1000, F-500; The displacement is 0 ~ 42l/s and the pressure is 5 ~ 32mpa.
Power: PZ 12V- 190, PZ8V- 190,12v135; Power 120 ~ 800 HP.
Rig: 27.5m/tower (750kN).
Drilling tools:? 127mm drill pipe. 203 drill collar, 178 drill collar+? 159 drill collar.
2.3 Directional drilling tools
? 172( 1.5? ) screws,? 165( 1.5? ) screw
? 172MWD directional sub,? 165MWD directional sub
? 165mm 、? 159mm short drill tappet
? 2 14mm centralizer,? 48MWD
? 165mm nonmagnetic drill collar, 172 nonmagnetic drill tappet.
3 drilling technology
3. 1 wellbore structure
Wellbore structure is in the most basic position in drilling engineering, which embodies the purpose of drilling and is also one of the important factors that determine whether this purpose can be realized smoothly. Wellbore structure design takes drilling purpose as the goal, and unifies the goal and process according to the actual drilling engineering and geological conditions.
First adoption? 3 1 1mm bit is drilled to the stable bedrock, and the hydrology shows normal. Run in? 244.5mm surface casing, cementing and setting for 48 hours.
Second adoption? 2 15.9mm bit is drilled to completion, and then run in after the drilling purpose is achieved? 139.7mm production casing and cementing.
3.2 bit selection
HJ537G bit is used to select suitable rocks in the second spudding.
3.3 Selection of power drilling tools
In order to adapt to soft and medium soft strata, a medium-speed and medium-torque motor is selected.
3.4 Selection of drilling fluid
Coal reservoir protection is the key to the construction of coalbed methane wells. In coal seam drilling, clean water drilling is mainly used to strictly control the solid content and specific gravity of drilling fluid. When there is a large amount of rock powder in the well, high viscosity pollution-free drilling fluid can be used to discharge rock powder, which can not only ensure the safety in the hole, but also prevent reservoir pollution.
4. Directional drilling components and drilling treatment measures
Directional well construction is mainly divided into three sections: vertical section, deflecting section and stable section. It is necessary to effectively select the three-stage drilling tool assembly according to different formations, different well depths and different displacement. Realizing the designed borehole trajectory is the key to construction.
4. 1 drilling technology in vertical interval
Deviation prevention in vertical section is an important guarantee for directional well construction. Generally, the deviation is required to be less than 100m. . The assembly of drilling tools in vertical well section is related to the difficulty of directional deflecting section in directional well.
(1) BHA: BHA tower is adopted in the first spudding. 3 1 1 bit+？ 203 drill collar+? 178 drill collar+? 159 drill collar+? 127 drill pipe.
Two open:? 2 15.9 bit+？ 178 drill collar+? 159 drill collar+? 127 drill pipe.
(2) drilling parameters: WOB 10 ~ 80 kN displacement 12 L/s pump pressure 0.5 ~ 2 MPa.
Drilling fluid performance: density1.02 ~1.10g/cm3 viscosity 21s.
(3) When encountering bedrock, gently press and turn slowly to prevent well deviation.
(4) When changing the diameter of the vertical interval, it must be hung, and the deviation should be recorded before replacing the directional drilling tool.
4.2 Drilling technology in deflecting section
After the kick-off section is lowered to the bottom, EMWD instrument starts non-interference directional drilling; 1.5 is adopted for construction? Single bending screw, the actual erection slope is 9? /30m。 In the process of orientation, sliding drilling and compound drilling are used alternately to ensure that the dog leg meets the requirements.
BHA？ 2 15.9 bit+？ 172( 1.5? ) screw+? 172MWD directional nipple+? 172 nonmagnetic * 1+? 178 drill collar * 2+411* 4a10+? 159 drill collar *9+? 127 drill pipe
(2) Drilling parameters: WOB 40 ~ 80 KN, displacement 20 ~ 24 L/s, pump pressure 2 ~ 4 MPa.
Drilling fluid performance: density 1.02 ~ 1.05g/cm3 viscosity 16 s.
(3) Adjust the performance of drilling fluid and adopt three-stage solid control equipment to control the solid content not to exceed the standard.
(4) Measure the well deviation and azimuth in time, and take immediate measures if it is found to be inconsistent with the design.
(5) Maintain mud performance, improve anti-collapse performance and rock carrying capacity, and clean the borehole.
4.3 Drilling Technology for Stable Inclined Section
The following three methods can be used to stabilize the drilling tool assembly in the inclined section of the well in this area, or they can be operated alternately to ensure that the deviation direction meets the requirements, and at the same time, the drilling parameters of the third shift should be maintained to ensure downhole safety.
(1) adopts screw compound drilling, and the inclination angle is stable.
Drilling tool assembly:? 2 15.9 bit+？ 172( 1.5? ) screw+? 172MWD directional nipple+? 172 nonmagnetic * 1+? 178 drill collar * 2+411* 4a10+? 159 drill collar *9+? 127 drill pipe
Drilling parameters: WOB 40 ~ 80 KN, displacement 20 ~ 24 L/s, pump pressure 3 ~ 5 MPa.
Drilling fluid performance: density 1.02 ~ 1.05g/cm3 viscosity 17s.
(2) Stabilize the deviation by using the near-bit centralizer.
Drilling tool assembly:? 2 15.9 bit+？ 2 14 centralizer+? 172MWD directional nipple+? 172 nonmagnetic *1+41* 4a10+? 159 drill collar *9+? 127 drill pipe
Drilling parameters: WOB 40 ~ 80 KN, displacement 20 ~ 24 L/s, pump pressure 2 ~ 4 MPa.
Drilling fluid performance: density 1.02 ~ 1.05g/cm3 viscosity 17s.
(3) Drill holes with smooth drill collars.
Drilling tool assembly:? 2 15.9 bit+？ 172MWD directional nipple+? 172 nonmagnetic *1+41* 4a10+? 159 drill collar *9+? 127 drill pipe
Drilling parameters: WOB 80 ~ 120kn displacement 20 ~ 24 L/s pump pressure 2 ~ 4 MPa.
Drilling fluid performance: density 1.02 ~ 1.05g/cm3 viscosity 16 s.
5. Experience and suggestions
Through the construction of FCC-HZ-23D, FCC-HZ-33D, FCC-HZ- 1 1D, FCC-HZ-47D and FCC-HZ-70D wells in this area, the following experiences have been gained:
(1) Timely inclinometer, accurate calculation and tracing are the keys to ensure borehole trajectory. MWD can accurately grasp the change of borehole trajectory and effectively control the trajectory.
(2) During drilling, observe the changes of torque and pump pressure at any time, and analyze and solve problems in time.
(3) Regularly measure the change of solid content in the mud to ensure that the solid content does not exceed the standard and does not affect the use of the screw. If possible, you can go to the third-level solid control equipment.
4 take it? Rotate+slide? The composite drilling method based on wireless real-time monitoring while drilling can effectively ensure the quality of borehole trajectory and make the construction safe and fast. Used in slope stability process? Rotate+slide? Composite drilling method can effectively reduce friction and torque and reduce construction risk.
(5) In the process of directional deviation building, the actual well deviation is slightly ahead of the designed well deviation, and the deviation building section is ended in advance, so that the actual drilling deviation in the stable deviation section is slightly smaller than the designed well deviation section, and the deviation is slightly increased in the composite drilling to meet the requirements of the design trajectory, so as to achieve the purpose of fast and safety. refer to
[1] Wang. In 2006, the present situation, geological characteristics and prospect analysis of coalbed methane exploration and development in Shouyang block. Beijing: Geological Publishing House.
Dagang oilfield. 1999. Drilling engineering technology. Beijing: Petroleum Industry Press
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