Method for inverting borehole expanding rate based on standpipe pressure change of gas drilling

Abstract

The invention discloses a method for inverting a borehole expanding rate based on standpipe pressure change of gas drilling. The method comprises the following steps: (1) in a normal drilling process, acquiring a standpipe pressure value of a borehole under a normal condition through a standpipe pressure meter, and reading a standpipe pressure value of an expanded borehole according to the standpipe pressure meter after the borehole is expanded in order to calculate a change value of the standpipe pressure before and after expanding; (2) calculating the accumulation thickness of rock debris at the bottom of a well through the change value of the standpipe pressure before and after expanding; (3) measuring the inner diameter of a casing and the outer diameter of a drilling rod through the known accumulation thickness of the rock debris to obtain the volume of the rock debris at the bottom of the well, namely, the expanding volume of an expanding segment; (4) calculating the volume of an original borehole according to the known mechanical drilling speed, drilling time and borehole radius of a drilling bit in a drilling process; (5) calculating the expanding rate of the borehole. By adopting the method, when the borehole of gas drilling is expanded, relevant information can be acquired immediately, so that specific measures can be taken, the drilling risk is lowered effectively, and loss is reduced.

Description

technical field [0001] The invention relates to a method for retrieving the borehole diameter expansion rate by standing pressure in gas drilling in the process of oil and natural gas development. Background technique [0002] Gas drilling is a drilling method in which compressed air or nitrogen is used as a circulating medium, and a gas compressor is used to inject compressed gas into the well, relying on the energy of the surrounding air to bring cuttings from the bottom of the well to the surface. With its advantages of fast drilling speed, low engineering cost and little damage to oil and gas layers, it can solve the problems of deep well depth, slow drilling speed, long cycle and high cost in the exploration and development of deep oil and gas resources. However, gas drilling is different from conventional liquid drilling, the wellbore pressure is low, and the phenomenon of well diameter expansion is serious. [0003] The expansion of the wellbore diameter will affect ...

AI Technical Summary

Problems solved by technology

However, gas drilling is different from conventional liquid drilling, the wellbore pressure is low, and the phenomenon of well diameter expansion is serious

[0003] The expansion of the diameter of the wellbore will affect the distribution of the flow field in the wellbore, change the actual working conditions in the wellbore, and increase the risk of drilling

During the drilling process of gas drilling, the diameter expansion of the wellbore leads to the change of the flow field in the wellbore, which in turn causes the dynamic suspension and retention of cuttings particles at the bottom of the wellbore. The cuttings in the expanding annulus fall back to the bottom of the well, causing the wellbore to be blocked, resulting in downhole complexity and serious damage to the drilling process

Images