Determination method for drilling fluid density in managed pressure drilling

Abstract

The invention provides a determination method for a drilling fluid density in managed pressure drilling. The determination method comprises the following steps: acquiring a formation pressure Pp, a collapse pressure Pb, a cracking pressure Pf, an allowable value Sb of a suction pressure, an allowable value Sg of a surge pressure, an allowable value Sk of a well kick adjusting pressure, a formationfracture safe added value Sf, a pressure difference allowable value deltaPn, a wellhead back pressure P and circular pressure consumption deltaP; determining the minimum density value rho2min of a drilling fluid in a stationary state, determining the maximum density value rho2max of the drilling fluid in the stationary state and determining the maximum density value rho4max of the drilling fluidin a circulating state; and determining the range of the density rho of the drilling fluid: rho is greater than or equal to Max(rho2min, rho4min) but smaller than or equal to (rho2max, rho4max). The determination method can determine the value range of density of the drilling fluid in managed pressure drilling effectively, so that the operating time of managed pressure drilling site operation is shortened, the operating cost is reduced, a well wall is maintained stable, various drilling accidents and complex conditions are avoided, and a reservoir can be also prevented from being polluted.

Description

technical field [0001] The invention relates to the field of oil and natural gas drilling, in particular to a method for determining the density of drilling fluid in managed pressure drilling. Background technique [0002] With the increasing demand for oil and gas and the development of oil and gas exploration and development, the drilling technology has gradually developed. In the process of conventional drilling, the choice of drilling fluid density often only considers the three pressure profiles, and the range of drilling fluid density is relatively small, and the value is relatively small. Large, it is very easy to cause greater pollution to the formation. Compared with conventional drilling, managed pressure drilling can adjust the wellhead back pressure, so as to control the ECD of the entire annular space, effectively control the bottom hole pressure, and solve the problem of safe drilling. Due to the increase of wellhead back pressure in managed pressure drilling,...

AI Technical Summary

Problems solved by technology

[0002]With the increasing demand for oil and gas and the development of oil and gas exploration and development, the drilling technology has gradually developed. In the conventional drilling process, the choice of drilling fluid density often only considers the three pressure profiles, Moreover, the range of drilling fluid density is relatively small and the value is relatively large, which is very easy to cause great pollution to the formation

Images