Abstract: The present disclosure relates to a cementing plug comprising a first plug body (bottom plug), a second plug body (top plug), and a plurality of cleaning portions. The first plug body comprises: a first body provided therein with a chamber opening towards a lower end thereof, and an upper end of the first body being provided with a pressure portion; and an anti-rotation portion provided on an inner wall of the first body, and capable of being connected to slurry entering the chamber to limit a rotation of the first plug body. The second plug body comprises a second body. The plurality of cleaning portions is provided on outer sidewalls of the first body and the second body along a length direction thereof, for scraping off residuals (mud cake) on an inner wall of a casing.

Abstract: The present invention relates to the technical field of well drilling, and discloses a plugging agent for temperature-resistant calcium-resistant water-based drilling fluid used in oil and gas reservoir protection, a drilling fluid, and uses of the plugging agent and the drilling fluid. The plugging agent for temperature-resistant calcium-resistant water-based drilling fluid used in oil and gas reservoir protection contains acrylamide-diallyldimethylammonium chloride copolymer modified graphene, wherein in the acrylamide-diallyldimethylammonium chloride copolymer, a molar ratio of structural units provided by acrylamide to structural units provided by diallyldimethylammonium chloride is 1:5-15, and the number-average molecular weight of the acrylamide-diallyldimethylammonium chloride copolymer is 15,000-30,000.

Abstract: A mechanical and hydraulic dual-effect expansion device for well drilling with expandable tubular technology includes an anchor having a lower end connected to an upper end of an insertion connection tube via a coupling, a hydraulic cylinder assembly comprising a hydraulic cylinder and a piston tube movably disposed within an inner cavity of the hydraulic cylinder, and a variable-diameter expansion cone assembly comprising a sealing cone portion and a variable-diameter expansion cone portion, wherein the sealing cone portion has an upper end connected to a lower end of the piston tube and a lower end connected to an upper end of the variable-diameter expansion cone portion. The mechanical and hydraulic dual-effect expansion device can facilitate completion of construction operations of an expandable tubular in a casing and an openhole system.

Abstract: The present invention relates to the technical field of well drilling, and discloses a plugging agent for temperature-resistant calcium-resistant water-based drilling fluid used in oil and gas reservoir protection, a drilling fluid, and uses of the plugging agent and the drilling fluid. The plugging agent for temperature-resistant calcium-resistant water-based drilling fluid used in oil and gas reservoir protection contains acrylamide-diallyldimethylammonium chloride copolymer modified graphene, wherein in the acrylamide-diallyldimethylammonium chloride copolymer, a molar ratio of structural units provided by acrylamide to structural units provided by diallyldimethylammonium chloride is 1:5-15, and the number-average molecular weight of the acrylamide-diallyldimethylammonium chloride copolymer is 15,000-30,000.

Abstract: The present invention relates to the technical field of well drilling, and discloses a temperature-resistant calcium-resistant water-based drilling fluid for oil and gas reservoir protection and a use thereof. The water-based drilling fluid contains a filtrate reducer and a plugging agent, wherein the filtrate reducer is a copolymer that contains structural units represented by formula (1), structural units represented by formula (2), and structural units represented by formula (3), wherein, the mass ratio of the structural units represented by formula (1) to the structural units represented by formula (2) to the structural units represented by formula (3) is (0.1-0.2):1:(0.05-0.1), and the number-average molecular weight of the copolymer is 10,000-100,000, the plugging agent is acrylamide-diallyldimethylammonium chloride copolymer modified graphene.

Abstract: The present invention relates to the technical field of petroleum and natural gas well drilling, and discloses a filtrate reducer for temperature-resistant calcium-resistant water-based drilling fluid used in oil and gas reservoir protection, a drilling fluid, and uses of the filtrate reducer and the drilling fluid. The filtrate reducer for temperature-resistant calcium-resistant water-based drilling fluid used in oil and gas reservoir protection contains structural units represented by formula (1), structural units represented by formula (2), and structural units represented by formula (3), wherein the mass ratio of the structural units represented by formula (1) to the structural units represented by formula (2) to the structural units represented by formula (3) is (0.1-0.2):1:(0.05-0.1), and the number-average molecular weight of the filtrate reducer is 10,000-100,000.

Abstract: A well cementation working solution prepared from red mud, slag and waste drilling fluids. The working solution is prepared from the following components in parts by weight: 100 parts of waste drilling fluids, 50-100 parts of slag, 5-50 parts of red mud, 4-7 parts of a suspension stabilizer, 1-7 parts of an activating aid, 0.5-5 parts of an anti-pollution agent and 0.4-3.5 parts of a diluent. The waste drilling fluids are waste waterborne drilling fluids. The slag is blast furnace slag or vanadium-titanium slag. The suspension stabilizer is sodium bentonite, carboxymethyl cellulose or a mixture of sodium bentonite and carboxymethyl cellulose. The activating aid is sodium metasilicate nonahydrate, sodium carbonate or a mixture of sodium metasilicate nonahydrate and sodium carbonate. The anti-pollution agent is sodium salicylate, potassium citrate or a mixture of sodium salicylate and potassium citrate. The diluent is sodium lignin sulfonate.

Abstract: A method for evaluating the breakage strength of first and second cemented surfaces of well cementation under a dynamic load, includes: producing a rock-set cement-casing composite structure sample; clamping the sample between an incident rod and an output rod of a Hopkinson rod, hitting the incident rod with a conical punch to generate incident waves, enabling the incident waves to pass through the sample to generate reflected waves and projected waves, recording dynamic strain signals of incident waves, reflected waves and projected waves, and converting the dynamic strain signals into electrical signals and transmitting the electrical signals to a computer; recording the process and the corresponding time point from breakage starting to a complete breakage of the first and second cemented surfaces by a photographic instrument; obtaining a strain rate time travel curve and a stress-strain curve, and obtaining the corresponding breakage strength by analyzing the curve peak points.

Abstract: The present disclosure provides a casing windowing method and tool using coiled tubing; the windowing method comprises the steps of: a) preparing a borehole, including drifting a casing, and scraping an inner wall of the casing; b) hanging a positioning assembly in the casing, including seating the positioning assembly at a wellhead of the borehole, and after the positioning assembly is put down to a predetermined position in the casing, hanging a hanger of the positioning assembly at the inner wall of the casing; c) fixing a whipstock at a down-hole of the borehole, including seating the whipstock at the wellhead, and inserting a guiding assembly of the whipstock into the hanger so that an orientation of a window inclined plane of the guiding assembly meets a requirement of window orientation; and d) windowing the casing, including seating a tapered windowing mill at the wellhead, and after the tapered windowing mill is put down to the window inclined plane of the guiding assembly, starting the tapered windo