Gas injection pressure-stabilizing drilling method

Abstract

The invention discloses an air-injection stable-pressure well-drilling method, which relates to a well-drilling method for petroleum and natural gas exploration and exploitation, in particular to a well-drilling method overcome the difficulties of fluid formation leakage, blowout and narrow safety window; the invention solves the difficult problems in prior well-drilling technology that: no possible to adapt to leakage, blowout and narrow safety pressure window reservoirs, but easy to result in blowout, leakage or both during the well-drilling process; during the course of drilling fluid circulation, the invention adopts an air-injection method with suitable volume of air to eliminate the auxiliary friction resistance and dynamic pressure in drilling fluid circulation; before stopping thecirculation, coming out of the hole or going into the hole, or in idling await status, repeatedly adopting pressure building, degasification, grouting and releasing high-pressure gas to fulfill balanced killing; before the air-injection stable-pressure well-drilling is executed, utilizing a MWD method to test reservoir parameters, so as to determine whether utilizes the method and how to utilize the method. The invention discloses the well-drilling method to decrease the downhole pressure variation window into a narrow line, so that the window can be completely included in the leakage and blowout safety pressure window; therefore, the invention adapts to well-drilling in exploration and development of oil and natural gas.

Description

technical field [0001] The invention relates to a drilling method for a fluid-containing formation, in particular to a drilling method suitable for a narrow blowout safety window in the process of exploration and exploitation of oil and natural gas. Background technique [0002] During oil and natural gas exploration drilling or production drilling, when drilling into a fluid-containing formation, such as oil, gas, water, etc., the formation has two pressures - pore pressure and leakage pressure. If the pressure of the drilling fluid acting on the bottom of the well is greater than the loss pressure of the formation, lost circulation will occur - the drilling fluid leaks into the formation; if the pressure of the drilling fluid acting on the bottom of the well is less than the pore pressure of the formation, a blowout will occur - the formation fluid enters the formation In the well, gushing to the ground. [0003] Both lost circulation and blowout must be avoided in effici...

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Problems solved by technology

[0015] The purpose of the present invention is to solve the fluid-containing formations where the existing drilling technology cannot adapt to the narrow "blowout safety pressure window", solve the technical problems of blowout, blowout or both blowout and leak in the drilling process of such formations, and provide a Regulating the amount of gas injection to conduct pressure-stabilized drilling to adapt to the drilling method of narrow "safety pressure window for leakage blowout" reservoirs

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