Vibratory Power Losses and Delivery to Rock During Rotary-Vibratory Drilling: Part I: Theory

1980 ◽  
Vol 102 (1) ◽  
pp. 102-109
Author(s):  
D. C. Ohanehi ◽  
L. D. Mitchell
Keyword(s):  
Dynamic Response ◽  
Theoretical Basis ◽  
Drilling Fluid ◽  
Blast Hole ◽  
Drill String ◽  
Power Delivery ◽  
Drilling Process ◽  
Power Losses ◽  
Rotary Drilling ◽  
Drilling Unit

This paper explores a possible theoretical basis for the failure of attempts to develop rotary-vibratory drilling units. With the critical needs in geothermal blast hole excavation and oil exploration, this nation cannot overlook the possibility of accelerating the drilling process by factors of 2 to 20 over the conventional rotary drilling rates. This paper develops the theory for the dynamic response of a vibrating drill string in a viscous drilling fluid with the energy lost to shear work. It develops the relations for power delivery to the rock as well as the total vibratory power to drive the system. Thus vibratory power losses can be computed by a difference. Part II of this paper applied this theory to a typical effort at developing a rotary-vibratory drilling unit. In the case studied, the power delivery was ineffective and at certain frequencies large losses resulted.

Integrated Multidisciplinary Solution for Improving Wellbore Stability and Drilling Efficiency in a Conglomerate Reservoir, a Case Study from North-West China

2021 ◽  
Author(s):  
Yalin Li ◽  
Jiangang Shi ◽  
Fang Zhang ◽  
Shanshan Wang ◽  
David Wiprut ◽  
...  
Keyword(s):  
Multidisciplinary Approach ◽  
Drilling Fluid ◽  
Junggar Basin ◽  
Wellbore Stability ◽  
Drilling Fluids ◽  
Drilling Process ◽  
Rotary Drilling ◽  
North West ◽  
Field Development ◽  
Weight Window

Abstract Drilling long horizontal development wells in a conglomerate reservoir with strong heterogeneity has been challenging in the Junggar Basin, onshore China. To develop the fields economically, rapid and safe drilling with minimal non-productive time (NPT) is required. However, various drilling problems such as stuck pipe, mud losses have been experienced in the build-up section while the horizontal conglomerate section experienced an extremely low rate of penetration (ROP). To overcome the drilling challenges, a thorough understanding of the subsurface characteristics of the formations is critical to develop effective engineering solutions. To improve drilling efficiency, an integrated multidisciplinary approach was applied to derive an effective drilling solution. Drilling experiences from offset wells were reviewed systematically to identify the possible reasons that have caused the drilling problems. This diagnostic approach helped to identify appropriate drilling solutions for mitigating the different drilling risks. Detailed geomechanical models were also constructed to understand the stress state and rock mechanical properties of the conglomerate reservoir and the overburden formations so that proper mud weights can be defined for each section to control both wellbore collapse and mud losses. Mud weight recommendations and failure mechanism diagnosis also provided the basis for drilling fluids designs. Additionally, in order to achieve a better hole quality as well as increase the reservoir contact and ROP, advanced rotary drilling systems were also used with real time monitoring. The latter enabled the tracking of rock property and ECD changes as well as other drilling parameters during the drilling process. This integrated solution was applied in the drilling of several horizontal wells. One typical case is presented in this paper. In this well, the risk of hole instability was very high because the well was targeting a deeper formation with a few shaly intervals in the build-up section which are known to cause serious wellbore stability problems. The safe mud weight window inferred from geomechanical analyses appears to be very narrow, particularly at the casing shoe where the mud weight required to control borehole collapse is very close or even higher than the fracture gradient. To help with drilling the well cost-effectively, drilling fluid was designed to perform three (3) critical functions - 1) maintaining wellbore stability, 2) increasing ROP and 3) broadening the mud weight window to minimize mud losses. The successful drilling of this well broke the drilling record in the same block. The integrated multidisciplinary approach successfully reduced the occurrence of borehole instability related problems and NPT in the study well. Following the same methodology, the drilling efficiency will improve with more experience and understanding obtained from continuous drilling. This continuous learning process will be the key aspect of this project, eventually contributing to the success of the field development.

pH-Sensor Under Consideration for Multi-Sensor-Chip in Downhole Drilling Fluid Monitoring

2017 ◽  
Author(s):  
Jonathan Kühne ◽  
Frederic Güth ◽  
Heike Strauß ◽  
Yvonne Joseph ◽  
Pál Árki
Keyword(s):  
Optical Sensors ◽  
Drilling Fluid ◽  
Drill String ◽  
Glass Electrode ◽  
Drilling Fluids ◽  
Drilling Process ◽  
Ph Sensing ◽  
Drilling Mud ◽  
Ph Sensors ◽  
Drilling Muds

Modern drill strings for the exploration of oil and gas are equipped with a variety of sensor carrying devices such as Measurement While Drilling (MWD), Logging While Drilling (LWD), and Formation Testing While Drilling (FTWD). These devices generate a large amount of downhole data, such as the orientation of the well, drilling parameters e.g. weight on bit and torque, and formation properties. Appropriate telemetry systems are included in the drill string to transfer relevant downhole data in real time to the surface. Other data is stored in memories downhole for subsequent evaluation. However, drilling fluid properties are still monitored at the surface and their behavior under borehole conditions is predicted with hydraulic models. Commercial solutions for a direct downhole measurement of various drilling fluid parameters are rare, though they would increase drilling process safety and the knowledge about the behavior of drilling fluids under real bottomhole conditions. The pH has a significant influence on the properties of water-based muds and plays a role in the chemistry of oil-based muds as the water cut in the emulsion increases. Commercial pH-sensing devices, such as the glass electrode, and optical sensors are not appropriate for the pH measurement under bottomhole conditions. Fragility, the insufficient degree of miniaturization, the low temperature and pressure resistance due to the liquid reference electrolyte, and phenomena such as the alkaline error are certain drawbacks of glass electrodes. Often optical sensors often will not capture the whole pH scale and require the medium to be at least slightly transparent for light. The usage of pH-sensors based on EIS (electrolyte-isolator-semiconductor) structures is a possible application of chemical sensors for drilling fluid monitoring under in situ borehole conditions. This paper presents results from a study on the behavior of an EIS structure as a pH sensitive electrode measured vs. a commercial Ag/AgCl reference electrode in comparison with a commercial glass electrode. EIS structures are capacitive pH sensors where the sensing layer is generally a metal oxide on a semiconductor substrate. Measurements in basic drilling muds were conducted under constant temperature and atmospheric pressure while the drilling mud was steadily stirred. The mud was titrated from alkaline to acidic conditions with hydrochloric acid and the pH was measured after potential equilibration at the electrodes. The results show a general feasibility for the usage of the proposed sensor. There are still certain challenges to be overcome in the development of a robust and reliable pH-sensing device for complex fluids, such as drilling muds under high pressure/high temperature (HP/HT) conditions.

Vibratory Power Losses and Delivery to Rock During Rotary-Vibratory Drilling: Part II, Application

1980 ◽  
Vol 102 (1) ◽  
pp. 110-114
Author(s):  
L. D. Mitchell ◽  
D. C. Ohanehi
Keyword(s):  
System Design ◽  
Theoretical Solution ◽  
Power Delivery ◽  
Power Losses ◽  
Design Changes ◽  
Drilling Unit ◽  
Improved Performance

This paper applies the theoretical solution developed in Part 1 of this paper to a rotary-vibratory drilling unit. The theory developed and applied in these papers explains possible causes for the failures of such devices to perform properly in the vertical vibratory mode. This paper predicts improved performance based upon system design changes. Power delivery as a function of depth is studied. Power delivery problems at great depths are uncovered. Further system redesign is suggested. The redesign implementation in the model results in recovery of the power delivery capability to the rock.

Analysis of Hydraulic Jarring Dynamics and Calculation of Impact Force

2014 ◽  
Vol 577 ◽  
pp. 129-134
Author(s):  
Hu Yin ◽  
Neng Luo ◽  
Qian Li
Keyword(s):  
Impact Force ◽  
Drilling Fluid ◽  
Maximum Velocity ◽  
Drill String ◽  
Acceleration Process ◽  
Drilling Process ◽  
Actual Process ◽  
Conservation Of Energy ◽  
Force Calculation ◽  
The Impact

Drilling jar is widely used to solve the stuck pipe incidents in the drilling process. Impact force which is being made during the jarring operation is acting on stuck point to achieve unfreezing effect. Conventional hydraulic dynamic load calculation method is not considering the impact of friction force on stress wave spreading in drill string. In actual process, friction and viscous resistance caused by the movement of drill string in drilling fluid, making drill string acceleration process exhibiting damped vibration characteristics. Therefore, with the drill string damping vibration theory, analysis of dynamics of acceleration process can be made, and displacement and velocity equation in longitudinal acceleration process can be deduced. Thus the maximum velocity of drill string before collision has been calculated, and impact force acting on the stuck point has been deduced with the law of conservation of energy and momentum. The model of impact force calculation is more satisfied with actual environment in the wellbore during jarring operation.

On the Importance of the Coupling Between Transient Mechanical, Hydraulic and Thermal Effects for the Modelling of Real-Time Drilling Operations

2019 ◽  
Author(s):  
Erik Wolden Dvergsnes ◽  
Eric Cayeux
Keyword(s):  
Real Time ◽  
Drilling Fluid ◽  
Mass Density ◽  
Thermal Conditions ◽  
Time Discretization ◽  
Drill String ◽  
Drilling Process ◽  
Drilling Operation ◽  
Improved Performance ◽  
Transient Models

Abstract Because of the increased importance for the drilling industry to deliver drilling automation solutions, model-based applications for the analysis and control of the drilling process, have become an attractive approach towards improved performance and increased safety. A critical characteristic for such applications is its ability to perform accurate simulations of the drilling operation in real-time, based on a detailed description of the wellbore. In a real-time context, the boundary conditions of the drilling system are seldom constant, therefore reinforcing the importance of utilizing transient models of the drilling process instead of steady state ones. Typical domains that require modelling are related to the mechanical, hydraulic and heat transfer aspects of a drilling operation. The time constants of the force-, momentum-, mass- and energy-conservation equations are sufficiently different to allow for solving each of these equations with different time discretization schemes. Yet, side effects influence the results from each other’s and therefore a time coupling shall nevertheless be accounted for. For instance, for a drilling operation conducted on a floater, the heave induced movement at the top of the string propagates along the drill-string, therefore causing a displacement that induces swab and surge pressure variations, which themselves generate counter-acting forces on the drill-string. In such conditions, both the mechanical and hydraulic frictions generate heat that changes the in situ thermal conditions and therefore the drilling fluid mass density and its rheological behavior. Consequently, heat exchange caused by the drill-string and fluid movements also influences the hydraulic response of the system. Furthermore, thermal expansion will also apply to the drill-string. In this paper, we discuss recent advances related to the coupling between transient mechanical, hydraulic and thermal models, where a key criterion is that the combined drilling model shall be capable of running in real-time on a standard computer. Incorporating these transient models is considered a necessary step towards improved accuracy of simulations, especially on floaters, where heave effects become important. We illustrate various effects by presenting and discussing several simulations results in detail.

scholarly journals Drill rig with a down-the-hole hammer for regulating the drilling rate by changing the air flow

2021 ◽  
Vol 326 ◽  
pp. 00018
Author(s):  
D Yungmeister ◽  
E Gasimov
Keyword(s):  
Mechanical Properties ◽  
Air Flow ◽  
Physical And Mechanical Properties ◽  
Drill String ◽  
Drilling Process ◽  
Drilling Rate ◽  
Rotary Drilling ◽  
Adjustable Valve ◽  
The Cost ◽  
The Impact

At present, a lack of efficiency of the rotary drilling intensification can be observed at mining enterprises that employ drill rigs. Due to this, we propose to enhance the rotary drilling using shock loads by installing a down-the-hole (DTH) hammer into the drill string of the rig for roller drilling, for instance, SBSh-250. The paper discusses the issue related to an increase in the drilling rate using a drill rig with DTH hammer and adjustable valve that regulates the air flow. The paper considers different types of drilling in engineering and geological surveys. Rocks were sampled for various types of drilling. The physical and mechanical properties of rocks, which affect the drilling process, were considered. The study focuses on a significant increase in the drilling rate through an increase in the impact power. As part of the study, an improved drill rig with a down-the-hole hammer controlled by a radio receiver was developed. When analyzing the physical and mechanical properties, it was shown that the control of DTH hammer operation enables fast drilling of complex rocks without reducing the drilling rate. An increase in the drilling rate of self-propelled equipment using DTH hammers installed above the drill bit will reduce the cost of drilling and extend the service life of the working tool.

scholarly journals Kinematics and dynamics analysis of new rotary-percussive PDM drilling tool

2021 ◽  
pp. 146134842198915
Author(s):  
Jialin Tian ◽  
Xuehua Hu ◽  
Liming Dai ◽  
Lin Yang ◽  
Yi Yang ◽  
...  
Keyword(s):  
Drill String ◽  
Structure Design ◽  
Drilling Process ◽  
Analysis Model ◽  
Drilling Tool ◽  
Stick Slip ◽  
Rate Of Penetration ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Impact

This paper presents a new drilling tool with multidirectional and controllable vibrations for enhancing the drilling rate of penetration and reducing the wellbore friction in complex well structure. Based on the structure design, the working mechanism is analyzed in downhole conditions. Then, combined with the impact theory and the drilling process, the theoretical models including the various impact forces are established. Also, to study the downhole performance, the bottom hole assembly dynamics characteristics in new condition are discussed. Moreover, to study the influence of key parameters on the impact force, the parabolic effect of the tool and the rebound of the drill string were considered, and the kinematics and mechanical properties of the new tool under working conditions were calculated. For the importance of the roller as a vibration generator, the displacement trajectory of the roller under different rotating speed and weight on bit was compared and analyzed. The reliable and accuracy of the theoretical model were verified by comparing the calculation results and experimental test results. The results show that the new design can produce a continuous and stable periodic impact. By adjusting the design parameter matching to the working condition, the bottom hole assembly with the new tool can improve the rate of penetration and reduce the wellbore friction or drilling stick-slip with benign vibration. The analysis model can also be used for a similar method or design just by changing the relative parameters. The research and results can provide references for enhancing drilling efficiency and safe production.

Study of stick–slip suppression and robustness to parametric uncertainty in drill strings containing torsional vibration tool using sliding-mode control

2021 ◽  
pp. 146441932110452
Author(s):  
Jialin Tian ◽  
Jie Wang ◽  
Siqi Zhou ◽  
Yinglin Yang ◽  
Liming Dai
Keyword(s):  
Torsional Vibration ◽  
Complex Dynamics ◽  
Sliding Mode ◽  
Parametric Uncertainty ◽  
Drill String ◽  
Lumped Parameter Model ◽  
Drilling Process ◽  
Drill Bit ◽  
Stick Slip ◽  
Drilling Operations

Excessive stick–slip vibration of drill strings can cause inefficiency and unsafety of drilling operations. To suppress the stick–slip vibration that occurred during the downhole drilling process, a drill string torsional vibration system considering the torsional vibration tool has been proposed on the basis of the 4-degree of freedom lumped-parameter model. In the design of the model, the tool is approximated by a simple torsional pendulum that brings impact torque to the drill bit. Furthermore, two sliding mode controllers, U1 and U2, are used to suppress stick–slip vibrations while enabling the drill bit to track the desired angular velocity. Aiming at parameter uncertainty and system instability in the drilling operations, a parameter adaptation law is added to the sliding mode controller U2. Finally, the suppression effects of stick–slip and robustness of parametric uncertainty about the two proposed controllers are demonstrated and compared by simulation and field test results. This paper provides a reference for the suppression of stick–slip vibration and the further study of the complex dynamics of the drill string.

Pipe stick problems of deep well drilling

2021 ◽  
Vol 66 (05) ◽  
pp. 192-195
Author(s):  
Rövşən Azər oğlu İsmayılov ◽  
Keyword(s):  
Drilling Fluid ◽  
Drill Pipe ◽  
Drill String ◽  
Differential Pressure ◽  
Drilling Mud ◽  
Fluid Circulation ◽  
Well Drilling ◽  
Deep Well ◽  
Pressure Pipe ◽  
Bottomhole Pressure

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

Eccentric String Reamer for ECD Reduction in the Depleted Field of Gulf of Thailand GoT

2021 ◽  
Author(s):  
Nichnita Tortrakul ◽  
Chatwit Pochan ◽  
Nardthida Kananithikorn ◽  
Thanapong Siripan ◽  
Basil Ching ◽  
...  
Keyword(s):  
Drilling Fluid ◽  
Low Cost ◽  
Operating Cost ◽  
Cost Effective ◽  
Operational Reliability ◽  
Drill String ◽  
Fluid Loss ◽  
Gulf Of Thailand ◽  
Drilling Depth ◽  
Annular Clearance

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.

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