51 results about "Deepwater drilling" patented technology

The invention discloses a deepwater well drilling overflow early warning device and method, and relates to the technical field of petroleum engineering, the deepwater well drilling overflow early warning device comprises a data acquisition module, an environment compensation module, a data processing module, a data processing module and a data processing module, the data acquisition module is used for acquiring data during well drilling, and the data comprises underground bottom hole pressure, temperature, acoustic logging data, gamma logging data, underwater gas content data and overwater well fluid flow data; the environment monitoring module is used for monitoring environment changes and dynamically correcting data acquired by the data acquisition module by applying a real-time correction algorithm based on a neural network, and the data processing and analyzing module is used for cleaning the data of the data acquisition module, extracting features and transmitting the features to the early warning system module. Accurate environment data are obtained through the environment compensation module, the data are processed through a real-time correction algorithm, the influence of external interference such as water flow fluctuation and temperature change on sensor reading can be eliminated, and therefore the accuracy and reliability of the data are improved.

The invention relates to a preparation method and application of an inner-rigid outer-soft core-shell structure silicon dioxide blocking agent for marine drilling fluid, and belongs to the field of deepwater oil and gas drilling. N-vinyl-2-pyrrolidone, dimethyl diallyl ammonium chloride, acrylamide and 2-acrylamide-2-methylpropanesulfonic acid are polymerized and grafted on the surface of nano silicon dioxide to form the silicon dioxide blocking agent with a core-shell structure and a rigid inside and a soft outside; by means of rigid plugging of a nano material and deformation filling flexible plugging of a high-molecular polymer, shale micro-nano pores are efficiently plugged with rigid inside and flexible outside, so that the stability of a well wall is maintained, meanwhile, secondary generation of hydrates is effectively inhibited, and the safety and efficiency of deepwater drilling are improved; the plugging agent provided by the invention reduces the demand on a large number of thermodynamic inhibitors, not only saves the cost, but also has the characteristic of environmental protection.

The invention belongs to the technical field of deepwater oil and gas field drilling gas cut monitoring, and particularly relates to a deepwater drilling ultrasonic Doppler gas cut monitoring device and a transducer arrangement method thereof. According to the ultrasonic Doppler gas cut monitoring device, a brand-new ultrasonic Doppler transducer and transducer tool structure is designed, and the sound wave transmissivity between the ultrasonic Doppler transducer and the marine riser is improved, so that the ultrasonic Doppler gas cut monitoring device is more suitable for implementation working conditions of deepwater drilling seabed, more convenient to install and use and higher in monitoring efficiency. The deepwater drilling ultrasonic Doppler gas cut monitoring device comprises a transducer tool and a plurality of ultrasonic Doppler transducers, the transducer tool is composed of two annular straps; wherein the two annular strap bodies are both semicircular and are connected through bolts to form an integrated structure; a plurality of round holes are formed in the annular strap at equal intervals, and positioning pieces are welded in the round holes; a pressing piece is arranged at the positioning piece in a matched mode. The ultrasonic Doppler transducer is composed of a shell, a piezoelectric wafer, a backing layer and an oblique incidence acoustic wedge.

The invention provides a deepwater drilling method for inhibiting bottom stratum erosion of a multi-wellhead suction pile and the suction pile. The drilling method comprises the steps that guide pipes and pre-inclined casing pipes are prefabricated and installed at a plurality of wellheads at the top of a pile cylinder to form the suction pile, the pre-inclined casing pipes and the guide pipes at the same wellhead are sequentially arranged in a sleeving mode from inside to outside, and the pre-inclined casing pipes and the guide pipes are arranged at the same wellhead in a sleeving mode from inside to outside; the shaft sleeve is coaxial with the wellhead; the suction pile is conveyed to a water entry position opposite to the drilling position; the suction pile is put down and penetrates into the set position of the stratum; a first well hole with the preset depth is drilled downwards in each pre-inclined casing pipe, and a first casing pipe is placed downwards in each first well hole; cement is injected into the first casing pipe for well cementation, so that the preset pressure intensity is achieved, and stratum erosion is restrained; and a second well hole with the preset depth is drilled downwards in the first casing pipe, a second casing pipe is placed downwards in the second well hole, well drilling is completed, erosion of the bottom stratum of the pile barrel can be restrained, and stage well drilling operation can be completed safely and efficiently.

The invention relates to a deepwater drilling overflow leakage detection method and device, a medium and equipment. The method comprises the steps that a fluid mechanics model of deepwater drilling shaft-stratum-marine riser pressurization pipeline coupling flow is established; inputting related parameters of a shaft and a stratum and basic parameters of a drilling fluid into the model, calculating a flow resistance parameter between a reservoir and the shaft, a circulating pressure consumption parameter of the shaft and an annulus fluid inertia coefficient of the shaft, and establishing a nonlinear state and an observation equation; performing linearization processing on the nonlinear state and the observation equation; discretizing a linear state and an observation equation, constructing a state and observation matrix discrete equation at the current moment, and establishing a Kalman filtering correction prediction model at the current moment; and calculating a linear state and a state and observation coefficient matrix of the observation equation, inputting real-time drilling data and the state and observation coefficient matrix into the Kalman filtering correction prediction model, and finally obtaining a well kick and well leakage prediction result.

The invention discloses a drilling tool for underwater installation and recovery of a top locking assembly and a construction method.The tool comprises a mandrel, an outer body, a release ring and a recovery ring, the outer body is in threaded connection with the mandrel through one corresponding step face, and the other step face of the mandrel is sleeved with the release ring in a threaded mode; a C-shaped recycling ring is arranged in the first containing groove, the recycling ring is bounced off or compressed through vertical movement of the release ring, and the recycling ring is clamped to the top locking assembly to recycle the top locking assembly when bounced off. The mandrel is provided with a first transmission block and a second transmission block which both protrude out of the mandrel, and the first transmission block and the second transmission block are correspondingly arranged in the grooves of the top locking assembly in a matched mode. The top locking assembly can be lowered, installed, adjusted in clearance and locked through one-time drilling, and at least one-time drilling is saved; and the underwater unlocking and recycling function of the top locking assembly is integrated, additional special tool allocation is reduced, tool allocation is optimized, the deepwater drilling operation cost is saved, and the operation efficiency is improved.

The invention belongs to the technical field of deepwater drilling, and discloses a deepwater drilling system and a deepwater drilling method. The deepwater drilling system comprises a drilling ship, a waterproof unit, a regulation and control device, a blowout prevention device and a drilling device. The upper end of the waterproof unit is connected with a drilling ship and provided with a first penetrating channel. The regulation and control device is arranged at the lower end of the waterproof unit and provided with a plurality of connecting channels. The connecting channel has an open state and a closed state, and in the open state, the first penetrating channel communicates with the outside through the connecting channel. And the blowout preventer is arranged at the wellhead and is connected with the waterproof unit. And the first penetrating channel can be communicated with a second penetrating channel of the blowout preventer. The drilling device is arranged on the drilling ship and penetrates through the first penetrating channel, the second penetrating channel and the well mouth. The well drilling device is provided with a conveying channel, and drilling fluid can be conveyed to the lower end of the well drilling device through the conveying channel. When the system is used for drilling operation, the pressure borne by a stratum at a wellhead can be effectively reduced, and stratum fracturing is avoided.

The present application relates to the technical fields of deepwater drilling and workover technology of offshore oil engineering, and particularly relates to a joint for emergency release of a deepwater light drilling and workover underwater riser and an operating method thereof. The emergency release joint comprises an upper joint body and a lower joint body which are mutually butted. A locking assembly composed of a clamp and a support ring is arranged on the periphery of the butt joint, and an electromagnetic drive assembly is correspondingly arranged. Upper and lower blowout preventer modules are arranged on both sides of the butt joint along the fluid passage in axial opposition. The electromagnetic drive assembly is used to drive the support ring to move between two working positions, so as to control the locking or releasing of the clamp on the butt joint. In operation, the upper and lower blowout preventer modules are first controlled to be closed, and then the mechanical locking is released to realize the release of the joint. After reconnection, the mechanical locking is restored and the fluid passage is opened. The scheme is suitable for emergency release and subsequent reconnection of the deepwater riser under abnormal working conditions.

The present invention discloses a subsea wellhead simulation test device and a test method for deep - water offshore drilling. The device includes: a kettle body, the chamber of which is used to fill with soil layers; earth pressure gauges, which are used to be distributed in the soil layers; a surface conductor, the bottom end of which is located in the soil layer and the top end is located above the soil layer; a subsea wellhead device, which is installed at the top end of the surface conductor; a riser, which is connected above the surface conductor through the subsea wellhead device; a tensioner, which is connected to the top end of the riser; a platform device, which is arranged on the tensioner; an experimental frame, which is erected around the kettle body; a push - pull motion device, which is used to simulate the marine environmental loads and the motion of the platform device; a height - adjusting mechanism, which is used to change the height position of the push - pull motion device; and a controller, which is electrically connected to the earth pressure gauges, the subsea wellhead device and the tensioner. The present invention can simulate the influence of the marine environmental loads on the subsea wellhead in deep water to reveal the variation law of the interaction between the deep - water surface conductor and the soil body.

The present application relates to a kind of pressure shell for riser monitoring and its fixing device, which mainly includes pressure shell, first fixed support, second fixed support, throat hoop steel band. Wherein the reliability of pressure shell is improved by triple sealing of pressure shell. The design of core plate fixed by screw through sleeve and lower bottom surface of sleeve, clamping snap ring is fixed by buckle, and secondary fixing is guaranteed, so that the monitoring error of pressure sealing shell will not be increased due to relative motion between structures during monitoring operation. First fixed support is disassembled with second fixed support by the contraction of internal spring of stop pin, which is simple in structure, easy to operate, and enhances the quick convenience of installation and disassembly. Throat hoop steel band passes through the V-shaped plate of second fixed support, and the support is fixed on the riser before being lowered, which improves the flexibility and versatility of device installation. The present application can be widely applied in pressure shell and its fixing device for deepwater drilling riser monitoring.

The present invention relates to a deepwater drilling blowout emergency treatment device and method, belonging to the field of marine oil and gas deepwater drilling well control. Downhole throttling nipple and wellhead data collection nipple collect temperature, pressure and flow data in real time, and the collected data is transmitted to the emergency treatment center in real time; the treatment center performs real-time analysis based on the collected data, and then controls the throttling valve opening to generate throttling pressure drop to block the annulus; by controlling the power of the well-killing fluid injection pump, the upper part of the downhole throttling nipple is filled with well-killing fluid, and well-killing fluid is injected into the bottom of the well while the throttle valve is opened to release gas, thereby realizing efficient treatment of deepwater drilling blowout. The present invention coordinately ensures safe and efficient treatment after deepwater drilling blowout through downhole throttling cooling and plugging and well-killing fluid wellbore pressure control, can quickly control the blowout problem in the deepwater drilling process, and avoid the problem of wellbore scrapping after a blowout in a deepwater drilling well, providing theoretical and technical support for safe deepwater oil and gas drilling.

The invention relates to a deepwater drilling riser vibration monitoring device and method, and the device is characterized in that the device comprises a pressure-resistant housing, a circuit module, and a battery module; the pressure-resistant shell is installed on the marine riser, an inflation one-way valve and an exhaust connector are arranged on the pressure-resistant shell, an inflation one-way valve plug is arranged on the inflation one-way valve, and the inflation one-way valve is used for taking down the inflation one-way valve plug to inflate inert gas into the pressure-resistant shell when needed; the exhaust connector is used for replacing conventional air containing water vapor in the pressure-resistant shell when inert gas is filled; a circuit module and a battery module are arranged in the pressure-resistant shell, the circuit module comprises a vibration monitoring board, a CPU board and a power board, and the vibration monitoring board is used for monitoring six-axis vibration data of the marine riser in real time; according to the marine riser monitoring system, the marine riser can be accurately monitored, and the marine riser monitoring system can be widely applied to the technical field of marine deepwater drilling.

The invention belongs to the technical field of deepwater oil and gas field drilling gas cut monitoring, and particularly relates to a deepwater drilling gas cut monitoring method. According to the monitoring method, nonlinear dynamic characteristics of ultrasonic signals are extracted through multi-scale fuzzy divergence entropy, and a gas content value is obtained based on inversion of a support vector machine model subjected to sample training, so that quantitative monitoring and early warning of tiny changes of the gas content are realized; compared with an existing deepwater drilling gas cut monitoring method, the method has the remarkable advantages in the aspects of monitoring precision, dynamic response characteristics, noise interference resistance and the like, and accurate recognition and real-time quantitative monitoring of early weak gas cut signals can be achieved. A deepwater drilling gas cut monitoring method comprises the following steps that ultrasonic echo signals of gas-liquid two-phase flow are collected; extracting a multi-scale fuzzy divergence entropy value in the ultrasonic echo signal; and inputting a feature vector in the multi-scale fuzzy divergence entropy into the trained support vector machine classification model to obtain a gas content recognition result.

The application relates to a deep-water drilling chamber indoor vibration experiment device and an experiment method. The device comprises a derrick, a flexible drill string, a rigid drill string, a rock sample clamping mechanism, an air wave generator, a torque dynamometer and a sensor group. The actual marine environment is simulated through the air wave generator, and the dynamic characteristic parameters of the drill string system are collected through the torque dynamometer and the sensor, so that the problem that the actual marine environment load cannot be simulated, and the dynamic characteristic parameters of the drill string system cannot be accurately and comprehensively obtained in the prior art is solved.

The utility model discloses a continuous drilling tool for ocean deepwater drilling. The continuous drilling tool comprises a main body, a sleeve, a mandrel, a locking block, a locking block and a release ring, the inner surface of the body is provided with threads and screwed with the threads on the outer surface of the sleeve, a plurality of first through holes are distributed in the circumferential direction of the body, the locking blocks are located in the first through holes, a first containing groove is formed between the body and the sleeve, and the outer wall of the sleeve is provided with a wedge-shaped conical face with a downward inclined face. The mandrel is sleeved with the sleeve, a second containing groove is formed between the mandrel and the sleeve, a plurality of second through holes are distributed in the sleeve in the circumferential direction, the locking block is located in the second through holes, the release ring is located at the upper end of the locking block, and when the mandrel is locked, the front end of the locking block is located in the second containing groove. According to the utility model, the low-pressure conduit head can be tripped in once drilling and the drilling operation of the next borehole can be continued, so that the tripping times are reduced, the cost is saved, and the efficiency is improved.

This invention discloses an integrated logging-while-drilling (LOD) and measurement drill string assembly, relating to the field of oil and gas drilling engineering technology. It provides a series connection scheme for core protective drill string components, offering two switchable configurations: one with a mud motor and one without. Both configurations consist of an azimuth density neutron logging sub, a bidirectional communication power supply sub, an acoustic logging sub, a resistivity logging sub, an upper connecting sub, a flexible sub, a lower connecting sub, an azimuth gamma logging sub, and a steering actuator connected in series according to a fixed logic. The configuration with a mud motor only requires adding a mud motor at a designated location to complete the structural switch, without changing the series connection of the remaining subs. This assembly scheme is applicable to various drilling scenarios such as offshore exploration and development, deepwater drilling, complex directional wells, highly deviated wells, and horizontal wells. It enables integrated operations of geological steering, formation evaluation, and wellbore stability analysis during drilling, effectively improving drilling efficiency and reducing operational risks.

The present application belongs to the technical field of gas invasion monitoring of deepwater oil and gas field drilling, and particularly relates to a deepwater drilling gas invasion monitoring method. The monitoring method extracts the nonlinear dynamic characteristics of ultrasonic signals through multi-scale fuzzy divergence entropy, and obtains the gas holdup value based on the support vector machine model trained by samples, thereby realizing quantitative monitoring and early warning of the small change of gas holdup. Compared with the existing deepwater drilling gas invasion monitoring method, the present method has significant advantages in monitoring accuracy, dynamic response characteristics and anti-noise interference performance, and can realize accurate identification and real-time quantitative monitoring of early weak gas invasion signal. A deepwater drilling gas invasion monitoring method comprises the following steps: collecting ultrasonic echo signals of gas-liquid two-phase flow; extracting multi-scale fuzzy divergence entropy values in the ultrasonic echo signals; inputting the feature vectors in the multi-scale fuzzy divergence entropy values into the trained support vector machine classification model to obtain the gas holdup recognition result.

The invention relates to a test bed for controlling gas cut monitoring parameters, which comprises an experiment system main body module, a gas supply module and a monitoring and control module, and is characterized in that the experiment system main body module comprises an experiment rack, a transparent pipe and a simulation drill rod, the transparent pipe and the simulation drill rod are both mounted on the experiment rack, and the transparent pipe sleeves the simulation drill rod; a through hole is formed in the bottom surface of the experiment rack; a one-way valve is mounted at the bottom of the through hole; the gas supply module is connected with the through hole through a gas pipe; the monitoring and control module is connected with the gas supply module and used for controlling the gas supply amount of the gas supply module; the gas cut identification can be timely and effectively realized, so that the overflow phenomenon can be early warned, and the safety of deepwater drilling operation can be guaranteed.

The invention relates to the technical field of oil and gas development drilling engineering, in particular to an overflow and leakage coexistence experiment device for simulating coupling of a stratum and a wellbore and a using method thereof.The overflow and leakage coexistence experiment device comprises a wellbore simulation unit, a drilling fluid circulation unit and a simulation medium injection unit, and the wellbore simulation unit comprises the wellbore and a drill column. The experimental device is mainly used for simulating the rule of influence of overflow leakage parameters, drilling fluid physical property parameters and the like on wellbore fluid flow parameters and the like when overflow and leakage coexistence occurs in a fractured stratum and a permeable stratum, and the experimental device can help deep water drilling and research of a well control method when overflow and leakage coexistence occurs. Compared with the existing experimental equipment, the actual coupling condition of the stratum and the shaft in the drilling process and the overflow or leakage working conditions of different types of stratums can be simulated, so that the simulation of abnormal working conditions under various stratum conditions can be realized; and the experiment result is more in line with the change rule of the shaft fluid under the actual working condition.

The utility model relates to the technical field of deepwater drilling, and discloses a connecting structure, a second connecting piece is sleeved on a first connecting piece, in order to enhance the connecting strength between the second connecting piece and the first connecting piece, a detachable locking piece is arranged on the second connecting piece, the locking piece comprises a locking part and an inserting part, the locking part is integrally in a sector ring shape, and the inserting part is arranged between the locking part and the first connecting piece. When the locking piece is located at the second position, the meshing teeth are clamped into the tooth grooves, the first connecting piece and the second connecting piece are connected through the locking piece, the contact face between the first connecting piece and the locking piece is a sector-ring-like contact face defined by the tooth faces of the meshing teeth, and the contact area of the first connecting piece and the locking piece is large. And the joint can bear larger load. The inserting part penetrates through the second connecting piece, the limiting piece can be connected with the inserting part and lock the locking piece at the second position, displacement of the locking piece after the first connecting piece and the second connecting piece are connected is avoided, and the connection reliability of the first connecting piece and the second connecting piece is guaranteed.

The invention discloses an ultra-deepwater drilling well leakage double-leakage layer positioning method, which comprises the following steps: acquiring the basis of each well section, calculating hydraulic parameters such as the flow velocity of drilling fluid in an annulus, calculating the Reynolds number of the drilling fluid in the annulus, judging the flow state, and selecting a corresponding annulus friction resistance coefficient formula according to the flow state; judging whether well leakage is returned or not according to whether drilling fluid returns from a well mouth, and selecting a model to calculate the depth of the double-leakage layer according to whether the well leakage is returned or not; determining the maximum value Kmax of the annulus pressure consumption distribution coefficient according to the fact that the first leakage layer depth is smaller than the second leakage layer depth, and enabling the annulus pressure consumption distribution coefficient to circulate within the range of (0, Kmax); and substituting the obtained first leakage layer depth and the second leakage layer depth into a post-well-leakage circulating vertical pressure expression to calculate post-well-leakage circulating vertical pressure, and when the post-well-leakage circulating vertical pressure is close to a post-well-leakage actually-measured vertical pressure value and the relation between the leakage layer depth and the length of the drill column meets the model requirement, ending the circulation. And obtaining a final double-leakage-layer leakage horizon calculation result.

The application discloses an anti-wear repair core for deepwater drilling of the sea, and relates to the technical field of offshore oil drilling and production equipment. The anti-wear repair core for deepwater drilling of the sea comprises a repair core assembly, the repair core assembly comprises a repair core body, a plurality of axial locking units arranged on the inner circumferential wall of the repair core body in a spaced manner and a recovery ring arranged on the top of the inner circumferential wall of the repair core body, the axial locking unit comprises an axial locking pin which can be horizontally moved towards the center of the repair core body, and a plurality of wellhead anti-rotation units for locking the wellhead are arranged on the outer circumferential wall of the repair core body; a retracting and releasing assembly, the retracting and releasing assembly comprises a lowering tool which passes through the repair core body and is used for connecting a drilling tool at the bottom, the lowering tool is externally provided with locking leaves which are equal in number to the axial locking pins and are opposite to the axial locking pins in position, transversely arranged grooves matched with the axial locking pins are formed on the locking leaves, and the top of the locking leaves is provided with a matching surface matched with the bottom of the recovery ring.

The utility model provides a direction adjusting assembly and deepwater drilling completion system integrated testing device, including fixed base and movable base, the upper surface of fixed base is provided with the groove, the groove bottom of groove is rotatablely connected with the turntable, the upper surface of turntable is provided with the connecting seat, the upper surface of connecting seat is embedded with the connecting shaft, and the connecting shaft is connected with the movable base. One end of the connecting shaft away from the connecting seat is connected with the lower surface of the movable base; two inclined blocks are symmetrically arranged on the lower surface of the movable base relative to the connecting shaft, and the two inclined blocks are located in the swinging direction of the connecting shaft; a sliding frame is further arranged on the upper surface of the rotating disc in a sliding mode. According to the utility model, the movable base swings left and right, and then the rotary table is used for driving the connecting seat and the sliding frame to rotate, so that the movable base rotates, the movable base swings obliquely, and the orientation of the movable base is adjusted; finally, multi-angle adjustment of the deepwater drilling and completion system integrated testing device installed on the upper surface of the movable base is achieved.

The invention discloses low-C-high-Mn-Ni-Cu corrosion-resistant L555-grade subsea pipeline steel and a preparation method thereof, belongs to the technical field of subsea pipeline steel manufacturing, and aims to solve the technical problem that existing L555-grade pipeline steel is poor in corrosion resistance and low-temperature toughness. The low-C high-Mn-Ni-Cu corrosion-resistant L555-grade subsea pipeline steel provided by the invention is prepared from the following components in percentage by mass: 0.031 to 0.045 percent of C, 2.00 to 2.10 percent of Mn, 0.15 to 0.22 percent of Si, 0.60 to 0.80 percent of Ni, 0.31 to 0.40 percent of Cu, 0.15 to 0.20 percent of Cr, 0.020 to 0.030 percent of Nb, 0.010 to 0.015 percent of Ti, less than or equal to 0.008 percent of P, less than or equal to 0.002 percent of S, less than or equal to 0.004 percent of N and the balance of Fe and inevitable impurities. The L555-grade subsea pipeline steel provided by the invention has good corrosion resistance and low-temperature toughness, and is suitable for deepwater drilling riser main pipes and other pressure-bearing service components.

The invention discloses a deepwater drilling guide pipe installation depth design method based on a mechanical relationship among operation parameters, which comprises the following steps of: performing preliminary design of deepwater drilling guide pipe installation by utilizing soil parameters of an adjacent well to obtain the bearing capacity and the mud entering depth of the deepwater drilling guide pipe; the deepwater drilling guide pipe is installed through the obtained deepwater drilling guide pipe bearing capacity and the obtained deepwater drilling guide pipe mud entering depth, the deepwater drilling guide pipe real-time bearing capacity is solved through the mechanical relation during deepwater drilling guide pipe installation operation, and therefore the deepwater drilling guide pipe installation depth is corrected in real time till deepwater drilling guide pipe installation is completed; when the deepwater drilling guide pipe is installed, the shearing strength of each area in the installation and descending process of the deepwater drilling guide pipe is obtained through operation parameter analysis, and a basis is provided for follow-up guide pipe depth theoretical design of an adjacent well. The accuracy of the designed depth of the drilling guide pipe can be guaranteed, and a large amount of seabed soil sampling cost can be saved.

The split type suction pile comprises an upper half part and a lower half part, the top of the upper half part is designed to be sealed, the bottom of the upper half part is designed to be open, a suction pump butt joint opening and an exhaust port are formed in the top of the upper half part, a reserved well opening is formed in the center of the interior of the upper half part, and the top of the lower half part is an open type horn mouth. The bottom of the lower half portion is open, a butt joint step and an anti-rotation structure are arranged in the lower half portion, the bottom of the upper half portion can enter the lower half portion and is clamped through the butt joint step and the anti-rotation structure, and hoisting structures are arranged on the outer wall of the upper half portion and the outer wall of the lower half portion respectively. According to the method, the underwater wellhead with excellent stability can be built on the ultra-deep water soft soil surface layer, and follow-up installation of equipment such as a Christmas tree is facilitated.

The present application relates to the field of oil and gas development drilling engineering, and is an experimental device for simulating overflow and leakage coexistence of formation and wellbore coupling and a use method thereof. The former includes a wellbore simulation unit, a drilling fluid circulation unit and a simulation medium injection unit. The wellbore simulation unit includes a wellbore and a drill string. The present application is mainly used for simulating the influence law of overflow and leakage parameters and drilling fluid physical property parameters on wellbore fluid flow parameters when overflow and leakage coexistence conditions occur in fractured formation and permeable formation. The experimental device can help the research of deepwater drilling and well control methods when overflow and leakage coexistence occurs. Compared with the existing experimental equipment, the present application can simulate the actual formation and wellbore coupling condition in the drilling process and the overflow or leakage condition of different types of formation. Not only can the abnormal conditions under various formation conditions be simulated, but also the experimental results are more in line with the change law of wellbore fluid under actual working conditions.

The present invention provides a pressure control drilling system and a drilling method for deepwater drilling in deep sea areas. The system includes a riser rotation control sub, an MPD hydraulic control sub, a riser annulus sealing device, a riser four-way joint, etc., which are integrated on an independent drilling riser joint. It forms a system with its corresponding key surface equipment: MPD choke manifolds, MPD hydraulic control manifolds, MPD buffer manifolds, MPD filter manifolds, MPD mud-gas separators, etc., and is used in conjunction with equipment such as riser boost pumps, metering tank pumps, rotary tables, mud diverters, riser telescopic joints, riser tension rings, drilling risers, subsea blowout preventer stacks, subsea wellheads, etc. of conventional deepwater drilling equipment. The present invention can be applied to carry out pressure control drilling and related drilling operations on equipment such as semi-submersible drilling platforms and drill ships in deep water (water depth above 300m).

The invention provides a deepwater drilling complex drilling multiphase flow simulation system and method, and the system comprises a drilling multiphase flow simulation database which is used for storing and managing multi-source heterogeneous data in a drilling process; the data service architecture module is used for constructing a data service architecture of drilling multiphase flow analogue simulation; the data standardization and cleaning fusion module is used for processing multi-source heterogeneous data in the drilling process; and the analogue simulation and real-time optimization module is used for carrying out analogue simulation and real-time optimization on drilling multiphase flow. According to the technical scheme, real-time simulation and optimization of multiphase flow in deepwater drilling engineering are achieved.

This invention relates to a method for preparing and applying a core-shell structured silica plugging agent with a rigid inner structure and a flexible outer structure for marine drilling fluids, belonging to the field of deepwater oil and gas drilling. This invention uses N-vinyl-2-pyrrolidone, dimethyl diallyl ammonium chloride, acrylamide, and 2-acrylamide-2-methylpropanesulfonic acid polymerized and grafted onto the surface of nano-silica to form a core-shell structured silica plugging agent with a rigid inner structure and a flexible outer structure. By utilizing the rigid plugging of nanomaterials and the flexible plugging of polymer deformation, this method effectively seals the micro- and nano-pores of shale and mudstone, thereby maintaining wellbore stability. Simultaneously, it effectively inhibits the secondary formation of hydrates, improving the safety and efficiency of deepwater drilling. Furthermore, the plugging agent of this invention reduces the need for large amounts of thermodynamic inhibitors, saving costs and possessing environmentally friendly properties.