scholarly journals Parameter substantiation of supra bit jet pump for productive formation opening

2021 ◽  
Vol 44 (4) ◽  
pp. 433-440
Author(s):  
A. P. Melnikov ◽  
N. A. Buglov

The purpose of the study is to develop a supra bit jet pump taking into account the unsteadiness of low-speed drilling for crushing the cuttings injected from the annular space under productive formation opening. The article proposes a device for drill string bottom assembly intended for the initial opening of the productive formation. The device includes a supra bit jet pump and a colmatator. The jet pump creates an additional circulation loop of the drilling fluid above the well bottom, crushes the cuttings injected from the annular space in the mixing chamber and delivers it to the colmatator. An additional circulation loop above the well bottom creates a local drawdown of the formation while maintaining the hydrostatic pressure in the well. Crushing of cuttings in the mixing chamber of the jet pump occurs due to the creation of cross flows in the jet pump. The cross flows are provided due to the angular and eccentric displacement of the working nozzle of the jet pump relative to the mixing chamber. The colmatator creates an impermeable screen on the borehole wall for temporary isolation of the productive formation under initial opening. The conducted study allowed the authors to propose head characteristics of the jet pump taking into account the angular, eccentric displacement of the working nozzle. The head characteristic of the jet pump has been developed for the unsteady operation of the jet pump in the drill string bottom assembly. The head characteristics take into account the roughness of the flow path of the jet pump. Using the head characteristics, the permissible displacements of the working nozzle of the jet pump have been determined. Recommendations for the design of jet pumps for drill string bottom assemblies are proposed.

Author(s):  
Tarek Meakhail ◽  
Ibrahim Teaima

The slurry jet pump with scouring nozzle system can be used in dredging of sites, which are difficult to access or need handling of equipments that are used for the intake of pumping stations under bridges and concrete water channels. This system is suitable for sand, silt, sludge, mud, and other organic materials. The aim of this study is to investigate the performance of water and slurry jet pumps. The effects of the pump-operating conditions and geometries on its performance were investigated. The experimental rig was constructed in such a way that the driving nozzle diameter can be changed. In this study, three different diameters of driving nozzles, 10, 12.7, and 16 mm, have been used with one mixing chamber of 25.4 mm diameter (i.e. three different area ratios of R = 0.155, 0.25, and 0.4). Also, the effect of driving pressure has been investigated. The results show that increasing the area ratio decreases the maximum mass flow ratio. The results of computational fluid dynamics were found to agree well with actual values obtained from the experimental water and slurry jet pump.


2021 ◽  
Vol 2(73) (2) ◽  
pp. 22-32
Author(s):  
Denis Panevnyk ◽  

This article analyzes the possibility of increasing the efficiency of using downhole jet pumps by swirling the injected flow. To analyze the peculiarities of the local swirling of injected flow, design and technological parameters in the form of the inclination angle of guiding elements, the diameter of the helical trajectory described by the fluid particles, and the flow rates of the swirling flow are studied. Based on the application of the conservation law of fluid momentum in adjacent jets with a parabolic pressure distribution, equations to determine the pressure characteristic of a jet pump are obtained, taking into account the additional dynamic pressure made by swirling the injected flow. In the process of analyzing the obtained relations, has been set the dependence of the relative pressure growth and the efficiency of the ejection system under the conditions of injected flow swirling on the relative flow rate of a jet pump, and an inversely proportional dependence of the above parameters on its main geometric parameter in the form of the ratio of cross-sectional areas of the mixing chamber and the nozzle.


Author(s):  
Ye. I. Kryzhanivskyy ◽  
D. O. Panevnyk

Insufficient energy performance of ejection equipment and a high probability of non-operating modes of its operation reduce the efficiency of downhole jet pumps. The method of determining the design and operating parameters of the well ejection system, which provide the maximum efficiency of the jet pump, is presented.  The proposed algorithm for determining the optimal values of the geometric dimensions of the flowing part of the jet pump involves the construction of a series of pressure characteristics for different values of its geometric parameter, the calculation of the efficiency and the determination of the injection ratio and the relative pressure corresponding to its maximum values.  During the studies, the main geometric parameter of the jet pump varied in the range from 2 to 6, given that these geometric dimensions are used in jet devices common in the oil industry. The optimal dimensions of the current part of the jet pump are obtained in the process of studying its pressure characteristics, and the optimal dimensions of the washing system of the bit - in the process of studying the characteristics of the hydraulic system. The design of an at-bit ejection system, which allows to increase the mechanical drilling speed, the passage of the bit, to stabilize the moment on the bit, to reduce its level of vibration and to control the antiaircraft angles of the well is considered. The efficiency of using at-bit jet pumps is in the following: an increase in the mechanical drilling speed up to 18.7%, the passage of the bit up to 50.8%. The research established the optimal diameters of the working nozzle, mixing chamber and bit nozzles, the distance between the working nozzle and the mixing chamber, the injection ratio and the relative pressure of the at-bit jet pump. The obtained values ​​of design and mode parameters exclude the occurrence of cavitation modes of operation of the ejection system and allow the operation of jet pumps with maximum efficiency.


Author(s):  
O. Panevnyk

The method of choosing geometric parameters of the well hole pump which ensures its operation in the mode of maximum efficiency is proposed. According to the algorithm developed, the ratio of the diameters of the working nozzle, the mixing chamber and the diffuser of the jet pump, as well as the distance between the nozzle and the speed equalization chamber and the axial dimensions of the flow part elements are regulated. During the process of establishing the required dimensions of the elements of the ejection system, the nature of the free working jet into the mixing chamber of the jet pump is taken into account, which determines the shape and structure of the estimated ratios governing the axial distance between the working nozzle and the resuscitation chamber of the mixing streams. The relationship between the mixing chamber diameters and the working nozzle and the amount of the jet pump coefficient of ejection which ensures its operation with the maximum possible values of the ejection system efficiency is shown. The analytical nature of the establishment of hydraulic interconnections among the elements of the ejection system is complemented by the experience of the practical use of deep jet pumps in the implementation of certain technological processes of construction, operation and repair of oil wells.


2021 ◽  
Vol 66 (05) ◽  
pp. 192-195
Author(s):  
Rövşən Azər oğlu İsmayılov ◽  

The aricle is about the pipe stick problems of deep well drilling. Pipe stick problem is one of the drilling problems. There are two types of pipe stick problems exist. One of them is differential pressure pipe sticking. Another one of them is mechanical pipe sticking. There are a lot of reasons for pipe stick problems. Indigators of differential pressure sticking are increase in torque and drug forces, inability to reciprocate drill string and uninterrupted drilling fluid circulation. Key words: pipe stick, mecanical pipe stick,difference of pressure, drill pipe, drilling mud, bottomhole pressure, formation pressure


2021 ◽  
Author(s):  
Nichnita Tortrakul ◽  
Chatwit Pochan ◽  
Nardthida Kananithikorn ◽  
Thanapong Siripan ◽  
Basil Ching ◽  
...  

Abstract This paper presents a method of reducing equivalent circulating density (ECD) while drilling using eccentric string reamers (ESR) with adjustable gage stabilizer (AGS) in Gulf of Thailand (GoT). Reduced ECD in slimhole is desirable when drilling depleted reservoirs as reduced borehole pressure can reduce or delay drilling fluid loss events. Delaying losses can allow well depth to be increased with the prospect of penetrating otherwise unrealized pay horizons and increasing reserves capture. Several methods of reducing ECD were considered but most solutions included changing drill string and/or casing design specifications with prohibitive cost. A low-cost, low operational-impact solution was needed. Hole-opening is a method of increasing annular clearance, but well delivery requirements of ~4.5 days per well necessitates a one-trip solution without introducing significant ROP reduction or negatively impact bottomhole assembly (BHA) walking tendencies. Further, the preferred solution must be compatible with a high temperature reservoir drilling environment and must not undermine drilling system operational reliability. A simple but controversial tool for hole opening is ESR. ESR’s are simple in that there are no moving parts or cutter blocks to shift, and operating cost is low. They are controversial due to uncertainty that the tool eccentricity and drilling dynamics will successfully open hole to the desired diameter. Given that the intent of this hole-opening application is limited to creating annular clearance for fluid, not mechanical clearance, the eccentric reamer solution was chosen for field trial and potential development. A tool design challenge was to create a reamer geometry with the desired enlargement ratio (6⅛-in. to 6⅞-in.) while drilling, and reliably drift surface equipment and casing without complications. The ESR design must efficiently drill-out cement and float equipment as well as heterogeneous shale/sand/mudstone interbedded formation layers without significant vibration. If successful, the enlarged hole diameter will increase annular clearance, reduce ECD, improve hole cleaning, and allow drilling depth to be increased to capture additional reserves The plug and play functionality of the ESR required no changes to the existing rig site procedures in handling and making up the tool. The ESR drifts the casing and drills cement and shoe track with normal parameters. The ESR is run with standard measurements-while-drilling (MWD)/logging-while-drilling (LWD) AGS BHA and is able to reduce ECD providing the opportunity to drill deeper and increase barrel of oil equivalent (BOE) per each wellbore. Performance analysis has shown no negative effect on drilling performance and BHA walking tendency. The novelty of this ESR application is its proven ability to assist in increasing reserves capture in highly depleted reservoirs. The ESR is performing very efficiently (high ROP) and reliability is outstanding. In this application, the ESR is a very cost-effective and viable solution for slimhole design.


Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Knud Richard Gyland ◽  
Bjørnar Lund ◽  
Sneha Sayindla ◽  
...  

A laboratory scale flow loop for drilling applications has been used for evaluating the effect of lubricants on skin friction during drilling and completion with oil based or low solids oil based fluids. The flow loop included a 10 meter long test section with 2″ OD free whirling rotating drill string inside a 4″ ID wellbore made of concrete elements positioned inside a steel tubing. A transparent part of the housing was located in the middle of the test section, separating two steel sections of equal length. The entire test section was mounted on a steel frame which can be tilted from horizontal to 30° inclination. The drilling fluids and additives in these experiments were similar to those used in specific fields in NCS. Friction coefficient was calculated from the measured torque for different flow velocities and rotational velocities and the force perpendicular to the surface caused by the buoyed weight of the string. The main objective of the article has been to quantify the effect on mechanical friction when applying different concentrations of an oil-based lubricant into an ordinary oil based drilling fluid and a low solids oil based drilling fluid used in a North Sea drilling and completion operation.


Author(s):  
Ya. M. Kochkodan ◽  
A.I. Vasko

The article presents the main factors affecting the buckling when drilling vertical wells. The authors study analytically the effect of the weight on the bit and the force of the interaction of a drill string with a borehole wall using a uniform-sized arrangement of the bottom-hole assembly and the borehole wall which is located in a deviated wellbore when drilling in isotropic rocks in case the drilling direction coincides with the direction of the force acting on the bit. Differential equations of the elastic axis of the drill string are worked out. The solutions of these equations have given nondimensional dependences between the technological parameters. The authors have obtained the graphical dependences of the distance from the bit to the “drill string - borehole wall” contact point and the normal reaction of the bottom to the bit and the “drill string - borehole wall” clearance. The dependence for identifying the drilling anisotropy index in oblique beds is obtained. An interrelation between the anisotropy drilling index, the zenith angle, the bedding angle, the bottom-hole assembly, the borehole dimensions and the axial weight on the bit has been established. The authors have studied analytically the effect of the weight on the bit and the force of the “drill string - borehole wall” interaction, when installing the centralizer to the bottom-hole assembly. The differential equations of the elastic axis of the drill string with the centralizer in the bottom-hole assembly are obtained. It is established that with the increase in the axial weight on the bit and the “drill collars - borehole wall” clearance, the distance from the bit to the contact point of the borehole wall decreases; whereas with the increase of the deviation angle and the clearance, the pressure force of the column on the walls increases. It has also been established that the anisotropy drilling index reduces the distance from the bit to the point contact both in a slick BHA and in the bottom hole assembly with the centralizer. The presence of a centralizer in the bottom hole assembly increases the distance from the bit to the contact point between the string and the borehole wall, makes it possible to increase the weight on the bit without the risk of increasing a deviation angle.


2019 ◽  
Vol 10 (2) ◽  
pp. 363-371 ◽  
Author(s):  
Chunxu Yang ◽  
Ruihe Wang ◽  
Laiju Han ◽  
Qilong Xue

Abstract. It is well known that the influence of the internal and external drilling fluid on the lateral vibration characteristics of drillstring cannot be ignored. In this paper, experiment apparatus for simulating drillstring vibration was established. Hammering method is used to measure drillstring lateral natural vibration frequency when the internal and external drilling fluid is considered. The test results show that the drilling fluid can decrease the natural frequency of the drillstring. Based on the simulation model, considering the influence of the internal and external drilling fluid, an external drilling fluid additional mass coefficient is derived considering the dynamic pressure effect caused by external drilling fluid. Additional mass coefficient can get the result with high precision, which can meet the needs of the project. the simulation results are in good agreement with the test results, and the error is within 2 %. This work provides a useful attempt and lays the foundation for the dynamics of the drill string in the drilling fluid environment.


2011 ◽  
Vol 130-134 ◽  
pp. 1703-1707 ◽  
Author(s):  
Xiao Chun Dai ◽  
Jian Huo

The aim of the paper is to reveal the flow structure and the mixing process of a steam-jet pump by using a computational fluid dynamics code FLUENT. Discusses the effect on a steam-jet pump’s entrainment ratio when the throat diameter of the primary nozzle as well as the outlet diameter of the primary nozzle is varied. Analyzes the position of shock wave which will bring the steam-jet pump’s performance a great loss. The performances of a steam-jet pump are studied by changing back pressures while the distance between primary nozzle outlet and mixing chamber inlet (DPM) is varied. The entrainment ratios of a steam-jet pump with different values of DPM and different back pressures are calculated.


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