A detection method for wellbore circulation pressure loss in formation drilling with narrow safe density window
A technology of cycle pressure loss and detection method, which is applied in wellbore/well components, measurement, earthwork drilling and production, etc. It can solve the problems of inability to measure while drilling and pressure control in the detection process, so as to avoid a large amount of leakage and formation pressure effect of cracking and improving accuracy
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Embodiment 1
[0026] A method for detecting circulating pressure loss of wellbore drilling in a narrow safe density window formation, comprising the following steps:
[0027] 1) Stop the pump, quickly close several throttle valves to increase the casing pressure value Pc, and stop closing the throttle valves when the casing pressure value reaches the design casing pressure value Pcmax, where the design casing pressure value design casing pressure value Pcmax=P fm +P CD +△P,P fm is the estimated circulation loss value during drilling fluid circulation, P CD Casing pressure value during normal drilling; △P is the estimated circulation loss value error and an additional value for safety when considering drilling fluid circulation, 0.1≤△P≤7Mpa;
[0028] At this time, the bottom hole pressure BHP=P H +P C , and BHP>P L , then Pcmax+P H >P L , the wellbore fluid leaks into the formation, and the casing pressure Pc gradually decreases. When the bottom hole pressure BHP=the formation leakage...
Embodiment 2
[0035] On the basis of Embodiment 1, in step 1), according to the adjacent well data, the error compensation value ΔP is increased or decreased for the estimated circulation loss during drilling fluid circulation.
[0036] Correct the estimated circulation loss during drilling fluid circulation, improve the accuracy of the estimated circulation loss value, and correspondingly improve the accuracy of the design casing pressure value Pcmax, so as to facilitate accurate control of the casing pressure value and avoid a large amount of drilling fluid leakage or In the event of a safety hazard.
Embodiment 3
[0038] On the basis of Embodiment 1 or Embodiment 2, the design casing pressure value Pcmax<10.05Mpa.
[0039] The design casing pressure value Pcmax<10.05Mpa ensures safety and avoids formation fracturing, massive drilling fluid loss, and potential safety hazards.
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