Well killing method used for eliminating gravity displacement of horizontal well

Abstract

The invention discloses a well killing method used for eliminating the gravity displacement of a horizontal well. The method includes: determining the closing pressure of an annular preventer; openinga ram preventer; hoisting a drilling tool at the speed of 0.3m / s, closing a semi-sealing ram preventer consistent with the drilling tool in the well in size when the length of the hoisted drilling tool reaches the length of a horizontal section in a well bottom, and then opening the annular preventer; starting a drilling fluid pump and opening a throttle valve, regulating the throttle valve to allow casing pressure to be equal to well closing casing pressure before the overflow discharge of the drilling fluid pump, regulating the pump speed of the drilling fluid pump to well killing pump speed, keeping the pump speed unchanged, and reading standpipe pressure at the moment; keeping the pressure of a circulating standpipe unchanged until formation fluid is discharged out of the ground; measuring the well closing casing pressure and the well closing standpipe pressure during pump shutdown and well closing, and judging the well closing casing pressure and the well closing standpipe pressure. The method has the advantages that gravity displacement is eliminated, and one large technical difficulty of the well killing of the horizontal well is solved.

Description

technical field

[0001] The invention relates to a method for killing a horizontal well to eliminate gravity displacement, and belongs to the technical field of petroleum exploitation Background technique

[0002] There are horizontal wells in all oilfields in my country, but the well killing of horizontal wells is not mentioned in domestic and foreign textbooks. Since the horizontal section of the horizontal well is usually at the level of the oil and gas layer (target layer), gravity displacement always exists. In this way, there is always oil and gas at the wellhead during circulation, and there is still oil and gas at the wellhead when the drilling fluid density is increased.

[0003] And the existing well killing method is to adopt the primary well killing technique or the secondary well killing technique. The one-shot well killing technique is to pump the configured killing drilling fluid directly into the well after the well is shut in due to overflow, and discharge ...