A method for testing formation pressure bearing capacity before cementing

Abstract

The invention discloses a method for checking stratum loading capacity before well cementation. The method includes transferring drill pipes to the place of casing shoes after drilling is finished, setting well mouth pressurizing value according to maximum annular dynamic equal yield density in well cementation, pressurizing to the well mouth gradually, stopping checking when pressure at pumping pressure inflection point or at the well mouth reaches the set value, recording final pressure data, calculating stratum loading capacity at casing shoes, and performing Step 2 open hole stratum weak stratum loading capacity checking, if the stratum loading capacity meets requirements. With the method, weak stratum loading capacity can be accurately acquired, defects that stratum at upper casing shoe layer is easy to be omitted by traditional stratum loading capacity static checking methods are overcome, and blindness to confirm aggravated drilling fluid density and circulation discharge capacity by traditional stratum loading capacity static checking methods is avoided, and field operability is strong.

Description

technical field [0001] The invention relates to the technical field of petroleum and natural gas engineering, in particular to a method for testing formation pressure bearing capacity before well cementing. Background technique [0002] For pressure-sensitive formations with low pore pressure and easy leakage, accurately determining the pressure bearing capacity of the formation is helpful to scientifically design construction parameters and effectively prevent lost circulation, which is the key to ensuring cementing quality. At present, the formation pressure test methods used in well cementing at home and abroad mainly include two types: the static test method of the formation pressure capacity and the dynamic test method of the formation pressure capacity. [0003] The static test method of formation pressure bearing capacity is to test the formation pressure bearing capacity by means of wellhead pressurization. The specific steps are as follows: after running the drill ...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are as follows: Since the rheological properties of cement slurry with the same density are not the same as those of drilling fluid, empirical methods are used to estimate the density of aggravated drilling fluid and the design of cementing construction displacement, so that the pressure bearing capacity of the formation cannot be accurately judged, and it cannot be accurately guided. Cementing Construction Parameter Design

[0005] To sum up, the static test method of formation pressure bearing capacity and the dynamic test method of formation pressure bearing capacity currently adopted have deficiencies, which cannot accurately judge the pressure bearing capacity of the formation, cannot accurately guide the design of cementing construction parameters, and are difficult to meet the requirements of cementing construction

[0006] After searching, it has not been found to apply for a patent or publish a paper on the method of testing the pressure bearing capacity of the formation.