Some Factors of Formation Leakage in Water Well Drill Pipe Analysis

Classification:

Industry dynamics

Release time:

2020-06-19

【Summary Description】 Water well drill pipe analysis of some factors of formation leakage, first of all, what are the prerequisite factors of formation leakage?
water well drill pipeAnalysis of some of the factors of formation leakage, first of all, what are the prerequisite factors of formation leakage?
① There are pores, cracks or faults and karst caves in the stratum, and they are connected with each other, so that the mud has flow channels.
② Mud column pressure is greater than the pressure of liquid and gas in the formation.
③ Mud column pressure and its lateral pressure are greater than the fracture pressure of the formation itself, fracturing the formation, resulting in lost circulation.
水井钻杆
human factors
Misoperation of 1. causes lost circulation
(1) The well wall falls off and collapses, blocking the outer ring of the drill pipe, and holding back the formation when the pump is started.
⑵ The well is not clean, there are too many cuttings and lumps, the mud circulation is not smooth, the pump pressure is too high, and the formation is leaked.
⑶ The mud has large specific gravity, high viscosity and high shear force. The mud pressure is greater than the formation pore pressure, and lost circulation occurs. In this case, the mud specific gravity, viscosity and shear force will be reduced, and the lost circulation will stop.
(4) Mud packing of drill bit or centralizer leads to increased pump pressure and formation leakage.
5. The quiescent time of mud in the well is more than 24 hours, forming a strong network structure strength. When drilling, the mud does not circulate in sections, but goes straight to the bottom of the well, resulting in higher pump pressure when the pump is started, and finally the formation leaks.
The displacement of mud pump can not keep up, the amount of cuttings in the well is large, the pump pressure rises, and the pressure leaks the formation.
(7)water well drill pipeThe tripping speed is too fast, resulting in too high excitation pressure and pressure leakage formation.
Well leakage and blowout originally occurred in the well, but when the mud is weighted, the mud weight is too high, and the well leakage occurs again.
2. there are pumping wells around the well pad, the groundwater level drops, the pore pressure drops, forming a large negative pressure, and large leakage will occur after drilling through the formation.
In the process of exploitation of 3. oil and gas layer, the underground water level is raised, the pore pressure is reduced, and a large negative pressure is formed, and a large leakage will occur after drilling through the formation.
4. fracturing and acidizing increase the formation fissures, and water injection cleaning increases the formation pore pressure, which will lead to lost circulation.

Key words:

weilida drill