How to prevent sticking accidents during drilling

Introduction

Sticking accidents refer to the phenomenon of sticking and sticking during drilling construction. Due to the mud cake effect on the wellbore, the downhole drilling tools are obstructed, which can easily lead to stuck accidents. Therefore, it is necessary to take effective preventive measures, allocate relevant equipment reasonably, implement prevention measures, prevent sticking accidents, improve the safety of drilling construction, achieve the expected drilling construction goals, and meet the needs of oilfield exploration and development.

Drilling construction sticking accident

Sticking and sticking accidents are the most common sticking accidents during drilling construction. When the drill collar is stuck, the drilling tool cannot move, affecting the smooth progress of drilling construction. The drilling tool is stuck on the wellbore for a long time, and it adsorbs with the mud cake on the wellbore, forming an adsorption stuck drill.

If the performance of the drilling fluid does not meet the design requirements, it will inevitably lead to pressure difference sticking accidents. If the initial sticking accidents are not handled in a timely manner, it will make the sticking accidents more serious, increase the time for handling the accidents, prolong the drilling construction time, and affect the efficiency of drilling construction.

Reasons for sticking

The internal cause of sticking and sticking accidents is the attachment of mud cakes on the wellbore wall. Due to the pressure difference between the formation pores and the liquid column pressure of the drilling fluid, a sticking accident is formed under the action of the pressure difference, which is an external cause. Both sandstone and mudstone can produce filter cakes, causing sticking accidents. During drilling construction, improper combination of drilling tools, performance of mud that does not meet design requirements, or unreasonable control of drilling parameters can all cause sticking accidents.

Sticking and sticking can occur when the drill string is stationary, and the position of the sticking point cannot be the drill bit, but the part of the drill pipe or drill collar. Before or after the sticking accident, the circulation of drilling fluid is normal, and the pump pressure is also normal, without any special abnormal display. After sticking occurs, if the activity is not carried out in a timely manner, the sticking point may move upwards or reach the position of the casing shoe.

Accident handling measures

Timely handle sticking accidents and restore normal operation of drilling construction. By using the method of forceful movement, in the initial stage of a sticking accident, the drill pipe and drill collar can be vigorously moved to relieve the sticking accident. If a serious sticking accident occurs, using the method of active card release cannot achieve the effect of card release.

The treatment measures for shock jamming are to use a shock absorber to implement mechanical shock, explosive shock jamming, hydraulic pulse, and other methods to relieve sticking accidents. Restore the normal drilling construction status of the wellbore and achieve the expected drilling construction effect. Choose the best unblocking agent to reduce the soaking time on the wellbore and achieve the best unblocking effect. Be careful not to inject too much releasing agent, otherwise it will cause the collapse of the wellbore and also affect the normal progress of drilling construction.

Preventive measure

Like dealing with all accidents, prevention in advance is much better than remedial measures afterwards. Take effective technical measures to prevent sticking accidents, improve the efficiency of drilling construction, and meet the technical requirements of drilling construction.

Analyze the internal and external causes of sticking, optimize the wellbore trajectory, maintain cleanliness and hygiene, and use the optimal drilling fluid system to meet the technical requirements of efficient drilling construction and avoid sticking accidents. Optimize the drilling fluid system, maintain good lubricity, good filtration, suitable viscosity and shear force, and be able to circulate normally, carrying rock cuttings from the well to the surface. Strengthen the control of solid phase in drilling fluid, separate solid particles in real time, and prevent the occurrence of sticking accidents due to the presence of solid particles. When weighting the drilling fluid, high-quality weighting agents are selected to enhance the performance requirements of the drilling fluid. After sufficient stirring, they are added to the mud system.

Design a reasonable drill string structure, optimize the form of drilling tool assembly, apply screw drilling tool assembly, and use the inverted drilling tool form of directional drilling to achieve the expected efficiency of drilling construction. If the drill bit cannot rotate at the bottom of the well, minimize the contact area between the drill bit and the mud cake as much as possible to avoid sticking accidents.

During normal drilling construction, if the water hose malfunctions, it is not allowed to sit the square drill pipe at the wellhead for maintenance. If there is a sticking accident, the drill string cannot be rotated. The weight indicator, pump pressure gauge, and torque gauge must be flexible and reliable to ensure the smooth progress of drilling construction. Maintain good wellbore quality, avoid excessive mud cake formation on the wellbore, and prevent sticking accidents when the drill string approaches the wellbore.

During the process of moving the drilling tool, do not stop as much as possible. After conducting static inclination measurement, it is highly likely to cause sticking accidents. Reasonably control the drilling construction parameters to ensure that the performance of the drilling fluid meets the design standards. Real time control of drilling construction progress, optimization of mechanical drilling speed, prevention of sticking accidents, and improvement of drilling safety.

Summary

This article studies the measures to prevent sticking accidents in drilling construction, adopts the best drilling construction technical measures, prevents sticking accidents, improves mechanical drilling speed, ensures the smooth progress of drilling construction, and achieves the expected efficiency of drilling construction. Analyze the causes of sticking and sticking in the wellbore, take corresponding technical measures to solve the problem, restore the normal drilling construction status of the wellbore, and drill high-quality wellbore to meet the technical requirements of oilfield development.