Abstract: A method for evaluating a downhole working condition of a PDC bit includes: performing an indoor test, including performing a drilling test in different full-sized cores by using the PDC bit with different degrees of abrasion and balling under condition of given WOB and rotational speed, to acquire change characteristics of a WOB, a rotational speed, a torque, a ROP and a bit vibration of the PDC bit in different time domains; improving and perfecting an existing prediction model and evaluation method for the downhole working condition through data obtained by the test to obtain the method; reading parameters of the WOB, the rotational speed, the torque and the ROP in real time during drilling; determining the downhole working condition of the PDC bit by using the method in the improving and perfecting.

Abstract: The present invention relates to the field of petroleum industry phase oilfield chemistry, and specifically relates to a bionic and dual-phobic drilling fluid. The drilling fluid contains a bionic wall-fixing agent, a bionic lubricant, a super dual-phobic agent, a scrap-carrying agent and a bionic shale inhibitor. The present invention uses the theory of bionics and the theory of a downhole rock surface being double phobic as a basis. By means of using the bionic wall-fixing agent, the bionic lubricant, the super dual-phobic agent, the scrap-carrying agent and the bionic shale inhibitor, which have special properties of imitating animals and plants in nature, and using a series of bionic treatment agents, a set of bionic and dual-phobic drilling fluid systems, which corresponds to an unconventional, complex oil and gas well, is formed.

Abstract: A 4D quantitative and intelligent diagnosis method for spatio-temporal evolution of oil-gas reservoir damage types and extent includes: determining a characteristic parameter characterizing reservoir damage by each of a plurality of factors based on a spatio-temporal evolution simulation equation of reservoir damage by each of the plurality of factors; and determining an effective characteristic parameter characterizing the damage extent of the reservoir based on the characteristic parameter characterizing reservoir damage by each of the plurality of factors. The method quantitatively simulate the characteristic parameters of reservoir damage caused by the various factors and a total characteristic parameter of the reservoir damage.

Abstract: The present invention relates to the field of petroleum industry phase oilfield chemistry, and specifically relates to a bionic and dual-phobic drilling fluid. The drilling fluid contains a bionic wall-fixing agent, a bionic lubricant, a super dual-phobic agent, a scrap-carrying agent and a bionic shale inhibitor. The present invention uses the theory of bionics and the theory of a downhole rock surface being double phobic as a basis. By means of using the bionic wall-fixing agent, the bionic lubricant, the super dual-phobic agent, the scrap-carrying agent and the bionic shale inhibitor, which have special properties of imitating animals and plants in nature, and using a series of bionic treatment agents, a set of bionic and dual-phobic drilling fluid systems, which corresponds to an unconventional, complex oil and gas well, is formed.

Abstract: The invention provides a high temperature resistant Portland cement slurry and a production method thereof. The high temperature resistant Portland cement slurry comprises the following components by weight: 100 parts of an oil well Portland cement, 60-85 parts of a high temperature reinforcing material, 68-80 parts of fresh water, 1-200 parts of a density adjuster, 0.1-1.5 parts of a suspension stabilizer, 0.8-1.5 parts of a dispersant, 3-4 parts of a fluid loss agent, 0-3 parts of a retarder and 0.2-0.8 part of a defoamer. The high temperature resistant Portland cement slurry has a good sedimentation stability at normal temperature, and develops strength rapidly at a low temperature. The compressive strength is up to 40 MPa or more at a high temperature of 350° C., and the long-term high-temperature compressive strength develops stably without degradation.

Abstract: The invention relates to the technical field of oilfield exploration, and discloses a 4D quantitative and intelligent diagnosis method and system for spatio-temporal evolution of oil-gas reservoir damage types and extent. The method includes: determining a characteristic parameter characterizing reservoir damage by each of a plurality of factors based on a spatio-temporal evolution simulation equation of reservoir damage by each of the plurality of factors; and determining an effective characteristic parameter characterizing the damage extent of the reservoir based on the characteristic parameter characterizing reservoir damage rby each of the plurality of factors. The invention can quantitatively simulate the characteristic parameters of reservoir damage caused by the various factors and a total characteristic parameter of the reservoir damage.

Abstract: Disclosed are an expansion tool assembly, comprising: an expandable tubular; a guide shoe partially inserted into and connected to the lower end of the expandable tubular; a sealing sleeve arranged in the expandable tubular and connected to the upper end of the guide shoe; an expansion assembly comprising an expansion cone and expansion seat disposed inside the expandable tubular, wherein the lower end of the expansion seat is connected with hooks, which can be rested on the upper end of the sealing sleeve; an upper joint that is connected to the upper end of the expansion seat and can be connected to a drill string. A force transfer path can be established via connection between the expansion seat and sealing sleeve, so that expandable tubular weight is borne on the drill string. Unintentional expansion of the expandable tubular, caused by interaction between expandable tubular and expansion cone, can be avoided.

Abstract: Disclosed are an expansion tool assembly, comprising: an expandable tubular; a guide shoe partially inserted into and connected to the lower end of the expandable tubular; a sealing sleeve arranged in the expandable tubular and connected to the upper end of the guide shoe; an expansion assembly comprising an expansion cone and expansion seat disposed inside the expandable tubular, wherein the lower end of the expansion seat is connected with hooks, which can be rested on the upper end of the sealing sleeve; an upper joint that is connected to the upper end of the expansion seat and can be connected to a drill string. A force transfer path can be established via connection between the expansion seat and sealing sleeve, so that expandable tubular weight is borne on the drill string. Unintentional expansion of the expandable tubular, caused by interaction between expandable tubular and expansion cone, can be avoided.

Abstract: 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 are described. The filtrate reducer contains structural units represented by formulas (1), (2), and (3) herein. The water-based drilling fluid contains the filtrate reducer, and exhibits good inhibitive, rheological, filtrate reducing, and reservoir protection performance when it is applied in the drilling process in a high-temperature high-calcium deep salt-gypsum formation.

Abstract: A temperature-resistant calcium-resistant water-based drilling fluid for oil and gas reservoir protection and a use thereof is provided. 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: 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 invention discloses an expandable liner hanger system comprising a central pipe and an expandable pipe, with an expansion cone provided therebetween the central pipe and expandable pipe in a way that the expansion cone is movable along the central pipe, so that the expandable pipe is expanded; wherein, the expansion cone comprises an expansion cone seat move along the central pipe, and an expansion cone sleeve fitted over the expansion cone seat, the connection between the expansion cone seat and the expansion cone sleeve is configured in a way that the expansion cone sleeve can move upward together with the expansion cone seat along the central pipe so that the expandable pipe is expanded, and the central pipe can drive the expansion cone seat to disengage from the expansion cone sleeve.

Abstract: The present invention discloses an expandable liner hanger system comprising a central pipe and an expandable pipe, with an expansion cone provided therebetween the central pipe and expandable pipe in a way that the expansion cone is movable along the central pipe, so that the expandable pipe is expanded; wherein, the expansion cone comprises an expansion cone seat move along the central pipe, and an expansion cone sleeve fitted over the expansion cone seat, the connection between the expansion cone seat and the expansion cone sleeve is configured in a way that the expansion cone sleeve can move upward together with the expansion cone seat along the central pipe so that the expandable pipe is expanded, and the central pipe can drive the expansion cone seat to disengage from the expansion cone sleeve.

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 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: 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 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.