Estimation method of deep well surface layer well cementing slurry return height

Abstract

The invention discloses an estimation method of deep well surface layer well cementing slurry return height. The method includes the steps of firstly, putting a guide pipe string of corresponding sizeinto a 600-1200mm borehole formed by jet drilling, locking the wellhead, and allowing the guide pipe string to sit on an anti-settling plate; secondly, rotatably drilling a 480-720mm borehole, and putting a 420-380mm casing string into the borehole; thirdly, reversing a valve, feeding water to test pressure, and pumping into a disclosing solution with the volume being 0.02-0.04 fold of the annular volume of a 508mm casing; fourthly, sequentially pumping into spacer fluid and first cement slurry according to field conditions; fifthly, using an ROV to observe reversing out conditions, and performing back calculation when disclosing solution reversing out is observed to obtain the hole diameter enlargement rate of the 480-720mm borehole in the second step; sixthly, pumping into tail cement slurry according to the hole diameter enlargement rate, wherein the pumping quantity of the tail cement slurry is equal to spacer fluid volume*(1+hole diameter enlargement rate); seventhly, displacingseawater, relieving pressure, checking reflux, moving to the next step if the reflux is normal, and building pressure and waiting on cement setting if the reflux is abnormal. By the method widely applicable to the field of petroleum deep water well drilling, the cement slurry can be distributed in the whole surface annulus, the well cementing quality of the surface casing can be increased favorably, and field operation safety can be increased.

Description

technical field [0001] The invention belongs to the field of well drilling engineering for resources such as oil and natural gas, in particular to a method for returning high cement slurry to the surface layer of a deep water well. Background technique [0002] Deep-sea drilling and mining technology mainly refers to the positioning, installation, and control technology of underwater wellhead facilities in waters below 300 meters, the stability design, construction, and control technology of underwater structures in waters below 300 meters, and the safety of deep-water drilling and mining technologies. property analysis and risk control; drilling and completion technologies mainly refer to underbalanced drilling and completion technologies in offshore oil and gas fields; logging technologies refer to nuclear magnetic resonance logging technologies. [0003] During offshore deepwater drilling operations, due to the influence of factors such as ocean currents, wind waves, and ...