SY/T 5181-2000 Recommended Practice for Open Hole Gravel Packing and Sand Control
Some standard content:
ICS 75.020
Registration No.: 6822—2000
Petroleum and Natural Gas Industry Standard of the People's Republic of China SY/T 5181--2000
Recommended practice for gravel pack of sand controlofthenakedhole
2000-03-10 Issued
State Administration of Petroleum and Chemical Industry
2000-10-01 Implementation
SY/T5181—2000
Scope·…
References
Preparation and requirements for gravel packing construction
Preparation and requirements for special tools for gravel packing
Gravel packing design
Construction procedures and practices for gravel packing in open hole7
Commissioning work
Implementation quality requirements
10 Construction safety and environmental protection requirements
Appendix A (Standard Appendix)
Appendix B (Suggestive Appendix)
Gravel packing calculation formula
Format of gravel packing design training book for open hole
SY/T 5181—2000
This standard is a revision of SY/I5181—87 "Recommended Practice for Openhole Gravel Packing and Sand Control". The main contents of this standard to SY/I5181—87 are as follows: According to the requirements of GB/I1.1-1993, the foreword, scope, and referenced standards of this standard are added, and the chapter numbers are adjusted. At the same time, the additional instructions of the original standard are deleted, and necessary supplements are made to safety, environmental protection and other aspects, and the expression of the standard is standardized; the scope of application of the original standard is expanded; according to the progress of tools and process technology, the process classification, on-site operation, and technical parameters in the original standard are partially revised. This standard will replace SY/I5181—87 from the date of entry into force. Appendix A of this standard is the appendix of the standard. Appendix B of this standard is the appendix of the reminder. This standard is proposed by China National Petroleum Corporation. This standard is drafted by the Oil and Gas Production Professional Standardization Committee and the drafting unit is the Technical Engineering Department of Liaohe Petroleum Exploration Bureau. The main drafters of this standard are Liu Xicheng, Han Shubai, Zhang Jianjun, Lv Yan, Ye Dongmei, and Li Dan. This standard was first issued in December 1987, and this is the first revision. VWww.bzxZ.net
1 Scope
Petroleum and Natural Gas Industry Standard of the People's Republic of China Recommended practice for gravel pack of sand controlof the naked hole
Recommended practice for gravel pack of sand controlof the naked hole
SY/T5181—2000
Replaces 5Y/T5181-87
This standard specifies the technical parameters and construction parameters of tools, gravel and working fluid required for gravel packing of open hole, and specifies the design methods and principles of gravel packing engineering, as well as the construction procedures and technical requirements. This standard applies to the on-site construction of gravel packing and sand control in the open hole section below the 177.8rmm (7in) casing of sand control wells. 2 Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. SY/T5110-2000 Casing scraper
SY/T5182—87 Welded stainless steel screen pipe
SY/T5183—2000 Evaluation method for sand control effect in oil wellsSY/T5184—1997 Quartz sand for sand control operations in oil, gas and water wellsSY/T5185—87 Recommended method for performance evaluation of gravel packing sand control water-based sand-carrying fluidSY/T5587.16—93 Conventional well repair for oil and water wells Operation procedures for well-drilling and casing scraping SY/T6283-1997 Guidelines for health, safety and environmental management systems for oil and gas drilling SY6321-1997 Safety regulations for shallow-water oil production and underground operations SY6345-1998 Safety qualifications for shallow-water oil workers SY/I6362-1998 Guidelines for health, safety and environmental management systems for underground operations in oil and gas wells 3 Definitions
This standard adopts the following definitions.
3.1 Gravel-acking fluid Gravel of a certain specification is mixed with sand in a specified proportion to form a uniform gravel mixture required for filling soil. 3.2 Gravel-to-liquid ratio Ratio of gravel to packing fluid The ratio of the apparent volume of gravel (i.e. the natural accumulation volume of gravel) to the volume of sand-carrying fluid in the gravel-packing fluid. See formula (A1) in Appendix A (Appendix to the standard).
3.3 Gravel packing effectiveness The ratio of the actual amount of gravel filled in a gravel-filled sand prevention well (i.e. the apparent volume of gravel filled) to the theoretical volume of the filled well section. See formulas (A10) and (A11) in Appendix A (Standard Appendix). 3.4 Gravel settling effect The phenomenon that the accumulated volume of the filled gravel gradually returns to the compacted state due to the de-gelling and dilution of the sand-carrying fluid and the compaction of the formation in a gravel packing layer containing viscous sand-carrying fluid.
3.5 Gravel solubility Approved by the State Administration of Petroleum and Chemical Industry on March 2000 and implemented on October 1, 2000
SY/T5181—2000
The solubility of gravel in a certain acid (or alkaline) liquid (gas) solution. 3.6 Gravel shattering rate Rate of gravel shattering The content of fine sand crushed by gravel samples after the anti-shattering test (in a standard test tube with an inner diameter of 50.8 mm, under a pressure of 14.0 MPa, for 2 minutes).
3.7 High-density gravel pack technique Gravel filling technology with a sand-to-liquid ratio of gravel filling liquid greater than 0.50 and a sand-carrying liquid viscosity greater than 200 mPa*s. 3.8 Medium-density gravel pack technique Gravel filling technology with a sand-to-liquid ratio of gravel filling liquid of 0.15-0.50 and a sand-carrying liquid viscosity of 50200 mPa*s. 3.9 Low-density gravel pack technique Gravel filling technology with a sand-to-liquid ratio of gravel filling liquid less than 0.15 and a sand-carrying liquid viscosity less than 50 mPa*s. 4 Preparation and requirements for gravel packing construction
4.1 Preparation and requirements for drilling
4.1.1 Before the gravel packing device is installed, the casing wall must be thoroughly cleaned with a casing scraper. 4.1.2 The wellbore wall of the open hole section should be stable, and the well inclination angle, the change rate of the full angle of inclination, the wellbore expansion coefficient, and the horizontal displacement of the middle part of the oil layer must meet the design requirements.
4.2 Completion fluid requirements
According to the main physical and chemical properties of the oil layer lithology and fluid and the reservoir pressure characteristics, select the appropriate completion fluid and correctly formulate the various performance indicators of the completion fluid. When the formation pressure allows, try to make it free of solid phase, or the solid phase content should be less than 0.2%, and it does not contain bentonite components.
4.3 Requirements for sand-carrying fluid
4.3.1 The sand-carrying fluid should be filtered and have good compatibility with the oil layer. The additives contained in the sand-carrying fluid should be selected from materials that do not harm the oil layer.
4.3.2 When mixing gravel filling fluid, the sand-carrying fluid should have good sand suspension ability, good lubricity and fluidity, and be able to break the gel in time.
4.3.3 In addition to meeting the safety requirements of gravel filling operations, the sand-carrying fluid should also have stable chemical properties (including thermal stability), non-toxic, non-corrosive and other properties:
4.3.4 The performance measurement of the sand-carrying fluid shall be carried out in accordance with the provisions of SY/T5185. 4.4 Gravel filling quality
The quality of gravel filling shall comply with the provisions of SY/T5184. 5 Preparation and requirements of special tools for gravel filling
5.1 Reaming drill bit
5.1.1 Selection of reaming drill bit specifications:
In the closed state, the reaming drill bit should be able to pass freely through the upper casing and section: In the open and locked state, the opening size of the reaming drill bit cone arm should be approximately twice the diameter of the sand screen. 5.1.2 It is recommended to use KSB type 152rm×$305mm (6KSB6SB12T) hydraulic expansion drill bit, the structure of which is shown in Figure 1.
5.1.2.1 Locking diameter of cone arm when open: $305mm; Diameter of drill bit after cone arm is closed: 152mm. Dimensional tolerance shall meet design requirements.
5.1.2.2 Minimum pressure required to open cone arm is 1.0MPa. Minimum pressure required for hole expansion operation is 3.4MPac5.1.2.3 Safety sealing difference between square drill rod and sealing sleeve of hole expansion drill bit is 6.8MPa. 5.1.2.4 Cone and cone arm can be renewed after wear, and main body of hole expansion drill bit can be reused. 2
5.2 Gravel filling device
5.2.1 Composition of gravel filling device
The structure of gravel filling device is shown in Figure 2.
Force rod
One cone
Closed state
Open state
Figure 1: Schematic diagram of the structure of the reaming drill
5.2.1.1 Specifications and structure of the inner pipe string
a) High-density filling process:
SY/T 5181-2000
Joint top moment joint
Phosphine technology straightener
Bare casing
Elastic straightener
Sealing joint
Bottom helper
Outer pipe shoe
Connect and send into the pipe string
Magnetic filling process
Inverted joint
—Single vegetable valve
Adjustable length and short joint
Flushing and discharging
One music Differential valve
One adjustable length short joint
Insert light pipe
Inner pipe column
Figure 2 Schematic diagram of gravel packing device structure
The connection sequence from bottom to top is: 60mm insert light pipe+60mm adjustable length short joint+60m differential pressure valve (two) 160m×$73mm variable buckle joint+$73mm flushing (return) pipe+*73mm adjustable length short joint+*73mm single flow 173m reversed suppression joint.
b) Medium and low density filling process:
The connection sequence from bottom to top is: 73mm flushing (return) pipe+473mm single flow valve+$73mm reversed buckle joint. c) The 73r check valve of the inner pipe string can be moved to the delivery pipe string at the top of the inner pipe string, and designed into a check valve matching the 89mm drill pipe, and placed between the filling tool and the inverted (discarded) joint. d) In order to improve the filling rate of gravel, a rotating vibration inner pipe string structure can also be used. 5.2.1.2 Specifications and structure of the outer pipe string
a) High-density filling technology:
The connection sequence from bottom to top is: 127mm pipe plug + Φ127mm bottom screen + $127mm×60mm sealing joint + $127mm screen pipe + $127mm smooth sleeve + $127mm joint short section. 3
b) Medium and low density filling technology:
SY/T 5181-2000
The connection sequence from bottom to top is: Φ127mm pipe plug + 127mm screen pipe + 127mm bare casing + 127mm joint short joint.
5.2.1.3 External pipe string accessories
In the overlapping section of the casing, a set of rigid centralizers is welded 300mm below each bare pipe coupling. In the open hole section, elastic centralizers are installed on the screen pipe column. The spacing of the centralizers depends on the well inclination (for wells with an inclination angle less than 30, the spacing is 8-10m; for wells with an inclination angle of 30° to 45°, the spacing is 4 to 5m; for wells with an inclination angle greater than 45°, the spacing is 2 to 3m). 5.2.1.4 Rubber Cup Positive Circulation Filling Tool
It is recommended to use the ZT-120 rubber cup positive circulation filling tool and connect an inverted (lost) joint at the bottom. 5.2.2 Use and technical requirements of the main tools of the gravel filling device 5.2.2.1 Rubber Cup Positive Circulation Filling Tool
a) Applicable scope: 4177.8mmtm (wall thickness 8.05~10.86mm) casing (rubber cup packer has two specifications: Φ166mm, $161mm).
b) Rubber hardness of rubber cup packer: HS65~70. c) Maximum working pressure: 24.5MPa.
d) The filling tool should be tested for pressure before going down the well. The pressure in the test device is 24.5MPa, and the bed force decreases less than 0.5MPa within 30 minutes to be qualified.
e) The filling tool should be stored in a normal temperature warehouse and maintained regularly. 5.2.2.2 Welded stainless steel sand screen pipe
a) Welded stainless steel wire screen pipe:
The quality and technical specifications should meet the requirements of SY/T5182. b) Assembly of sand screen pipe: The technical requirements for assembly of sand screen pipe are shown in Table 1. Table 1 Technical requirements for assembly of sand screen pipe Conventional (ordinary) The stainless steel wire screen is fixed to the base pipe with electric welding points at both ends of the screen. The upper end of the screen slides freely, and the lower end is installed with a traction seal between the two ends of the stainless steel wire screen and the base pipe. Ordinary oil-resistant and water-resistant sealing packing is used. High temperature resistant (350℃), strong alkali resistant (pH>11) and oil-resistant and resistant are used. Two safety shear pins are installed, which can shear! The strength is 2/3 of the tensile strength of the screen
5.2.2.3 Special sealing packing for sealing joints and inserted light pipes
immersion
Maximum sliding movement of the screen
According to the maximum expansion margin of the outer pipe column, the maximum sliding movement of the screen is determined
When installing the screen, the position of the screen on the base pipe and the length and position of the drilling section of the base pipe body are determined according to the sliding movement
The inserted light pipe can freely enter and exit the sealing joint, and any part of it that contacts the sealing joint should be able to withstand a pressure difference greater than 2.9MIPa.
5.2.2.4 Differential pressure (guide) valve
The shear pressure (difference) of the safety shear pin of the JF differential valve is 10~1,2MPa, and the assembled differential pressure valve is tested at 0,8MPa. It is qualified if there is no leakage within 5min4
.
5.3 Lead Seal Smashing Device
5.3.1 Composition of Lead Seal Smashing Device
SY/T 5181--2000
The Lead Seal Smashing Device is composed of a sealing tool and a sealing joint. Its structure is shown in Figure 3. Upper joint
Kelly
Thrust bearing
Directional screw
Shear pin
Press-in joint
Lead seal press-in joint
Smashing tool
Undercut joint
Lower coupling
Figure 3 Schematic diagram of the structure of the Lead Seal Smashing Device
5.3.1.1 The sealing tool is mainly composed of an upper joint, a Kelly, a rolling undercut mechanism (composed of a lock ring, a thrust bearing, and a flat ring), an undercut (discarding) joint, and a lower coupling. 5.3.1.2 The lead seal joint is mainly composed of the main body, inner sleeve, self-locking ball, lead seal and press-fit joint. 5.3.2 Technical requirements for the use of lead seal smashing device 5.3.2.1 Smashing seal tool
The axial clearance value of the thrust bearing of the smashing seal tool should be adjusted to (1 ± 0.5) mm. During the smashing seal operation, the range of movement of the pipe string shall not exceed the maximum stroke of the square drill pipe of the smashing seal tool. The smashing seal tool must be cleaned after use; the threads of the rolling back mechanism and the reverse joint should be greased. 5.3.2.2 Lead seal joint
When the lead seal is in a 177.8mm casing and is subjected to a pressure of 90 to 110kN, its deformation and the sealing pressure difference generated by the casing should reach 10MPa.
The lead seal used in thermal wells should meet the requirements of long-term exposure to high temperature (350℃), strong alkali (pH>11) and resistance to oil immersion, water immersion, steam, oil flow erosion and other complex environmental conditions. The function of the self-locking ball is to prevent the sealing state formed by the deformation of the lead seal from changing. 5.4177.8mm casing scraper
SY/T 51812000
There are six blades evenly distributed on the scraper body, and each blade is equipped with four compression springs. Applicable pipe diameter: 4151--169mm;
Joint buckle type: 3'/,REG;
Blade hardness: HRC40--45
Other quality and technical specifications shall be implemented in accordance with the provisions of SY/T5110, 6 Gravel filling design
6.1 Gravel packing process classification and main parameter selection Gravel packing process is mainly classified by the amount of gravel contained in the gravel packing fluid (the main factor determining density) and the viscosity of the sand-carrying fluid, see Table 2.
Table 2 Gravel packing process classification parameters and applicable conditions Process type
Gravel packing fluid sand-to-liquid ratio, L/
Sand-carrying fluid viscosity, mPas
Filling displacement, L/min
Termination pressure, MPa
Well washing displacement, L/min
Application range
High density
200～300
Serious formation sanding, open hole wellbore| |tt||Unstable and with a well inclination angle less than 45°
Note: The viscosity of the sand-carrying fluid is measured at a shear rate of 100s-1 and room temperature. 6.2 Gravel and screen specification design
6.2.1 Gravel specification
Medium density
0.15~0.50
50~200
300～400
Highly deviated wells
Low density
400 500
Wells with relatively stable open hole walls and no formation loss
The selection range of filling gravel specifications is 48 times the median sieve particle size of the formation sand in the sand control layer section. From the industrial gravel specification series, find out those close to 5 times the median sieve particle size as the filling gravel specifications. 6.2.2 Screen Specifications
6.2.2.1 Selection of Screen Slot Size
The screen slot should be smaller than the minimum size of the gravel packing. Thermal recovery wells must consider the dissolution of the gravel packing by the hydrothermal flow, so the screen slot size should be 1/3~2/3 of the minimum gravel packing size.
6.2.2.2 Selection of Screen Diameter
The screen diameter of an open-hole sand prevention well is mainly determined by the wellbore size (including technical casing and open-hole section), the radial width of the gravel packing layer, and the oil production process. The radial width of the open-hole sand prevention gravel packing layer is generally in the range of 50~76mm. For an open-hole well with a 177.8mm casing on the upper part of the well body and a 305mm casing on the lower part, it is recommended to use a ±127--140mm screen. 6.3 Design of filling pipe string
6.3.1 Outer pipe string (sand control pipe string)
The length of the screen pipe section should be about 1.5m above the top and bottom of the oil-producing layer, and the smooth pipe section should overlap with the technical casing by 20-30m. Under normal circumstances, the outer pipe should be placed in a vertical position and the screen should not enter the technical casing. In addition to the required smooth pipe length on the screen pipe string, the length of the screen pipe section should be increased as much as possible.
The specifications of the outer pipe fence should match those of the screen pipe (see 5.2.2.2 and 6.2.2.2). 6.3.2 Inner pipe string (construction pipe string)
SYT 5181--2000
It is advisable to insert the smooth pipe into the sealing joint 2/3 to 1/2, and the differential valve should be about 4.5m higher than the sealing joint. The above requirements are all achieved by adjusting the length and short section of the inner pipe string up and down.
6.3.2.1 The diameter of the inner pipe string should be increased as much as possible to reduce the gap between the inner and outer pipe strings, increase the flow resistance, force the mortar to flow to the lower part of the screen with low resistance, realize the gravel filling from bottom to top, and ensure the filling quality. The recommended ratio of the outer diameter of the inner pipe string to the inner diameter of the screen is 0.70.8.
6.3.2.2 To ensure the safety and quality of the gravel filling operation, the length of the inner pipe string should be 3m-4m shorter than the outer pipe string. 6.4 Calculation of gravel filling volume (apparent volume of gravel) The theoretical filling volume is calculated according to formula (A2) in Appendix A (Appendix of the standard). The gravel filling volume is increased by 20% to 50% on the basis of the theoretical filling volume.
6.5 Calculation of sand-carrying fluid content
The sand-carrying fluid content of the gravel filling fluid is calculated according to formula (A3) in Appendix A (Appendix of the standard). The sand-carrying fluid for filling operation is calculated according to the gravel filling volume and the designed sand-liquid ratio calculated in accordance with Article 6.4 and substituted into formula (A3). 6.6 Gravel filling operation procedure and technical parameter design 6.6.1 Gravel filling operation procedure and downhole process 6.6.1.1 Gravel filling operation is carried out according to the following procedures (liquid flow path is shown in Figure 4): Send down the filling device
Circulate filling gravel
Pull out tools and inner pipe
Put in wrong sealing joint
Figure 4 Schematic diagram of gravel filling operation procedure and lifting process a) Lower gravel filling device b) Connect and clean the surface manifold, and test the pressure according to the designed maximum pump pressure; d) Inject pre-fluid; d) Inject gravel filling fluid; d) After filling the estimated gravel volume, replace it; the filling is completed; g) Determine the filling liquid arrival position and the filling situation in the well according to the pumping volume and the pressure change rate, and decide the next step: g) Backwash; h) Invert, pull out the filling tool and inner tube; i) Lower the lead seal and seal device; j) Install the lead seal joint: k) Pull out the seal tool. SY/T5181—2000 6.6.1.2 A combined gravel filling device can also be used to complete all the operations of gravel filling and lead sealing in one downhole process. 6.6.2 Design of technical parameters for gravel packing operation 6.6.2.1 Pre-flushing liquid injection
Under the premise of not damaging the stratum, use a flushing liquid with good flow performance and stable wall-joining effect (add a certain amount of anti-swelling agent, etc.) as the pre-flushing liquid. The injection volume of the pre-flushing liquid is generally half of the filling volume, and the pump injection displacement is 300-400L/min. 6.6.2.2 Gravel filling liquid injection
The filling displacement of the gravel filling liquid shall meet the design requirements of Table 2. The injection volume of the gravel filling liquid shall be calculated according to the relevant formulas (A7) to (A9) in Appendix A (Standard Appendix). 6.6.2.3 Displacement
The pre-displacement liquid uses clean water, and the displacement volume is 1.2 times the volume of the delivery string and the ground connection manifold. When the pressure does not rise after the liquid displacement is completed, a certain amount of gravel should be prepared to be filled again. Relationship between displacement fluid volume and displacement:
When the gravel packing fluid passes through the filling tool conversion hole, the displacement displacement should be reduced to less than 150L/min; when the displacement fluid passes through the gravel packing layer, the displacement displacement should be increased to more than 400L/min. 6.6.2.4 Backwash
Backwashing uses up the liquid. The backwashing fluid volume is generally 15 times the volume of the input string. If the construction is abnormal, the backwashing mouse can be increased to the annulus volume between the wellbore and the input string. The backwashing displacement is 500~900L/minc6.7 Open hole gravel packing design
Fill in the "Open hole gravel packing design" according to the requirements of Appendix B (suggested appendix) and submit it to each construction unit in time. 7 Open hole gravel packing construction procedures and practices 7.1 Drilling pilot holes
7.1.1 Preparations before drilling into the oil layer
The construction team should be equipped with a well washing fluid purification circulation system that meets the requirements, a full set of drilling tools and tools for construction, and a completion fluid that meets the design requirements: make a gravel packing construction design; and carry out technical training for the construction team. 7.1.2 Drilling pilot holes and completion electrical testing
7.1.2.1 Use a drill bit of Φ152mm~155mm to drill the pilot hole. Use clean water to drill the cement base, and replace the completion fluid before entering the oil layer. 7.1.2.2 To ensure that the various performance indicators of the completion fluid meet the design requirements, a full set of performance tests must be performed twice per shift, and maintenance and treatment must be carried out in a timely manner.
7.1.2.3 After drilling the design and depth, clean and raise the bottom, and adjust the completion fluid performance: start drilling, and conduct completion electrical testing. 7.2 Hole expansion and electric well logging
7.2.1 Inspection of the reamer bit before lowering into the well
7.2.1.1 Measure the length and outer diameter of the reamer bit in the closed state. 7.2..2 Push the kelly drill rod of the reamer bit manually (or stand it on the ground) to expand the cone arm to the locked position. Measure the maximum diameter of the drill bit palm opening, the opening radius of each cone, and the distance from the cone to the threaded step of the kelly drill rod. 7.2.1.3 Comprehensively inspect the wear of the drill bit body, the fixing of the cone arm shaft pin, the shaking of the cone, and the flexibility of rotation. 7.2.1.4 Connect the reamer bit under the kelly drill rod and lower it to the wellhead. Start the pump and pay attention to the pump pressure when the drill bit kelly arm is opened. 7.2.1.5 During the process of starting and stopping the pump, pay attention to observe whether there is puncture leakage in the sealing part of the drill bit body, whether there is obstruction when the cone arm is opened or closed, etc. 7.2.2 Requirements for the use of reaming drill bits
7.2.2.1 When replacing the drill bit, the tongs must not be engaged at the sealing part between the drill body and the square drill rod. 8
SY/T 5181—2000
7.2.2.2 Before drilling, install a core or core plug in the water hole of the center rail blocker as needed. 7.2.2.3 When the downhole situation is abnormal, the reaming drill bit must not be lowered. If there is resistance during drilling, do not press violently. It is strictly forbidden to use the reaming drill bit as a reaming tool.
7.2.2.4 Strictly reaming according to the specified reaming drilling speed, the drill should be evenly hooked to prevent the appearance of spiral barrels and irregular well walls. 7.2.2.5 Do not lift the reaming drill bit when the pump is turned on to prevent accidents caused by the opening of the locked cone arm and the encounter with the casing shoe or small borehole rain. 7.2.2.6 It is strictly forbidden to slip the drill or drill slowly when reaming, and pay attention to the changes in the downhole conditions to prevent the cone from falling. 7.2.2.7 After the reaming is completed, flush the well with a large displacement and adjust the performance indicators of the completion fluid. The drill can only be started when the performance of the exit completion fluid meets the design requirements.
7.2.2.8 When the reaming drill bit is raised to the casing shoe, it should be raised slowly. If the drill bit is stuck at the casing shoe and cannot be lifted suddenly, the drill bit can be lowered to the bottom of the well, the pump can be turned on, and the hole can be reamed for 3-~5 minutes; or the displacement can be increased to flush (and the completion fluid performance can be adjusted), or the drill bit can be rotated at a higher speed (within the safety range) to close the cone arm. 7.2.2.9 When replacing the cone and cone arm, they should be installed according to their serial numbers. At the same time, check whether the axis pin of the cone arm is worn or deformed. If abnormal, replace it in time.
7.2.2.10 The weight of the drill chain for hole expansion should be twice the maximum drilling pressure. 7.2.3 Hole expansion
7.2.3.1 Lower the hole expansion drill bit to the original casing cement wall position, start the pump to ream the hole, and remove the cement ring remaining on the casing wall. 7.2.3.2 Create a hole expansion "transition zone";
When the drill bit enters the designed hole expansion well depth (generally within 0.5~1.0m below the casing shoe), start the pump and rotate it in place at the depth of the well for 3~5min to form a step on the wall. Then, gradually apply a drilling pressure of 5.0~10.0kN, slowly expand the hole downward, and stop the pump after about 0.5m of penetration. Lift the drill tool to the original step depth position, and repeat the original operation 2 to 3 times. 7.2.3.3 Determine whether the cone arm is open and in the standard locking working state: When the drill bit can add a certain amount of drilling pressure on the created "transition zone" and it shows that it has been opened and locked, stop recording and continue to expand the hole for 2 to 3 minutes. If the actual drilling pressure can be added, it means that the drill bit has been opened and locked, and you can continue to expand the hole downward. If it fails, you need to lift the drill tool to the original step depth position and create the "transition zone" repeatedly. If you suspect that the lower wellbore is too large or the well wall has been damaged, you can pump it gradually downward (without rotating the drill tool) until you can add drilling pressure! And start expanding the hole from the depth of the well where you encounter resistance.
7.2.3.4 Expanding drilling speed:
During the expansion process, it is required to send the drill evenly, keep the drilling pressure constant, and do not allow to release it in one second. The footage shall not exceed 0.30m for every 100r rotation of the drill bit. 7.2.3.5 Technical parameters for hole expansion:
a) Drilling pressure: 20.0~40.0kV. The drilling pressure of the hole expansion drill bit is determined by the type of cone, the lithology of the formation and the width of the hole expansion step;
b) Speed: 60~80r/min. The speed of the hole expansion drill bit is half of the speed of the ordinary cone drill bit with the same size of the drill bit body; c) Displacement: 900~1440L/min. The displacement should be able to remove the cuttings after hole expansion in time; d) Pump pressure: 3.4~6.8MPa. The pump pressure required for hole expansion should take into account the influence of the lithology of the formation on the hole expansion speed. 7.2.4 Connecting single root
7.2.4,1 Before connecting the first single root, a square margin of 0.30m should be left to effectively handle the jam of the hole expansion drill bit near the casing shoe.
7.2.4.2 Before each single connection, the following should be done carefully: reaming twice (reaming speed 1-2m/min). Then start the pump and slowly lower it from the original reaming depth to check whether there is any resistance to the wall. If resistance is found, re-reaming should be done. 7.2.4.3 After connecting a single root, start recording and re-reaming slowly; when the drill bit is 0.5-1.0m away from the reaming step, the drill bit is gradually lowered without rotating until it hits the "bottom" of the reaming hole again; then it is slightly lifted up to make the cone leave the "bottom" of the hole, drive the turntable, and gradually increase the drilling pressure to reame. If the drill bit fails to hit the "bottom" of the reaming support, the reaming drill bit should be lifted to the large wellbore to take measures such as inserting a pressure ball or increasing the pump circulation displacement to open the cone arm again.
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