scholarly journals THE APPLICATION FEATURES OF DIRECTIONAL BHAS WHILE DRILLING DIRECTIONAL WELLS

2019 ◽  
pp. 17-24
Author(s):  
I.I. Chudyk ◽  
A.M. Livinskyi ◽  
Akhmed Al Tanakchi ◽  
A.M. Pastuch
Keyword(s):  
Design Feature ◽  
Axial Displacement ◽  
Energy Costs ◽  
Assembly Design ◽  
Bottom Hole ◽  
Drilling Method ◽  
Bottom Hole Assembly ◽  
Energy Consuming ◽  
Analytical Research ◽  
Physical And Mechanical Characteristics

The article presents a scientific and practical approach to assessing the energy efficiency of directional bottom hole assembly on the basis of the mud motor. The main design feature of these assemblies is the presence of a bent angle in the spindle section of the mud motor. The conditions of operation of such assemblies are considered for a combined drilling method with a various number of stabilizers. Particular attention is paid to determining the causes of unproductive energy costs on the work of the directional bottomhole assemblies in the borehole.The mathematical model improved by the authors includes the geometric features of the assembly design, the bent angle of the spindle of the mud motor as to its body, the number of the stabilizers and the location of their installation, the borehole inclination angle, the physical and mechanical characteristics of the subsurface rock that forms it. The authors calculated the energy consumption for rotation and the axial displacement of the assemblies in the directional well taking into account the deflection forces on the bit and the reaction on the stabilizers. The researchers suggest the use of the indicator of specific energy costs to overcome the forces and moments of the environment resistance during the work of the directional assemblies using the method of combined drilling.Using the results of analytical research and the developed approach the authors study energy costs for thework of the directional bottom hole assemblies with a various number of the stabilizers. The study is conducted for the slick assemblies, as well as for assemblies with one- and two-stabilizers. It is established that directional assemblies with one stabilizer are characterized by the highest values of the forces of resistance of axial displacement and rotation in the directional well. As they are high-torque, energy-consuming and the most energy-intensive systems, their practical use is limited. The main factors in the formation of energy costs for the work of directional assemblies while applying the combined drilling method are the number of the stabilizers and the inclination range.

Bottom Hole Assembly Design Enhancement Successfully Eliminate Hole Problems and Reduce Significant Drilling Time : South S Field Case Study

2020 ◽  
Author(s):  
Y. D. Mulia
Keyword(s):  
Contact Area ◽  
Cost Savings ◽  
Assembly Design ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Unconsolidated Sand ◽  
Bottom Hole Assembly ◽  
Drilling Parameter ◽  
Drilling Time

For S-15 and S-14 wells at South S Field, drilling of the 12-1/4” hole section became the longest tangent hole section interval of both wells. There were several challenges identified where hole problems can occur. The hole problems often occur in the unconsolidated sand layers and porous limestone formation sections of the hole during tripping in/out operations. Most of the hole problems are closely related to the design of the Bottom Hole Assembly (BHA). In many instances, hole problems resulted in significant additional drilling time. As an effort to resolve this issue, a new BHA setup was then designed to enhance the BHA drilling performance and eventually eliminate hole problems while drilling. The basic idea of the enhanced BHA is to provide more annulus clearance and limber BHA. The purpose is to reduce the Equivalent Circulating Density (ECD,) less contact area with formation, and reduce packoff risk while drilling through an unconsolidated section of the rocks. Engineering simulations were conducted to ensure that the enhanced BHA were able to deliver a good drilling performance. As a results, improved drilling performance can be seen on S-14 well which applied the enhanced BHA design. The enhanced BHA was able to drill the 12-1/4” tangent hole section to total depth (TD) with certain drilling parameter. Hole problems were no longer an issue during tripping out/in operation. This improvement led to significant rig time and cost savings of intermediate hole section drilling compared to S-15 well. The new enhanced BHA design has become one of the company’s benchmarks for drilling directional wells in South S Field.

Optimizing Bottom Hole Assembly Design Criteria to Improve Mechanical Performance in Slim Hole Drilling Environment

2021 ◽  
Author(s):  
Stephen Fleming ◽  
Roberto Ucero ◽  
Yuliya Poltavchenko
Keyword(s):  
Mechanical Performance ◽  
State Of The Art ◽  
Hole Drilling ◽  
Force Analysis ◽  
Software Suite ◽  
Assembly Design ◽  
Positive Displacement ◽  
Drilling Performance ◽  
Bottom Hole ◽  
Bottom Hole Assembly

Abstract After analyzing the historical data of neighboring wells adjacent to the drilling site, 11 bit trips were required due to the low mechanical performance of the bottom hole assembly elements. This observation is based on maximum circulation hours and low helical bucking values that make it uneconomic to drill the sections with a positive displacement motor drive system. A redesign the bottom hole assembly was proposed to achieve an improved mechanical performance which allowed the section to be drilled with a single assembly. With a focus on increasing the mechanical limitations of the downhole elements, the use of 4 ¾" equipment is considered instead of the 3 ½" standard equipment used in this hole size. One of the biggest challenges was modifying the 4 ¾" positive displacement motor (PDM) to fit into the 5 ½" hole given that the mud motor has a maximum unmodified diameter of 5 ½". Using the force analysis module of a State-of-the-art BHA modelling software suite, multiple iterations were performed to simulate and validate an alternative PDM design and accompanying directional assembly. This new design featured modifications to an existing 4 ¾" PDM deploying a long gauge bit in combination with a fit for purpose measurement while drilling system. After numerous runs using this assembly design, it was found that there was no additional or unexpected wear of the modified Mud Motor components or associated elements of the downhole equipment. These observations act to validate the pre-job engineering force analysis. With the improved mechanical specifications of the 4 ¾" Bottom Hole Assembly (BHA) components, circulating hours were increased from 100 hours to 250+ hours in a stepwise process. This enabled drilling of the entire 5 ½" section with a single BHA, comparing favorably to the legacy approach with an average of eleven bit runs. The modified 4 ¾" PDM coupled with long gauge bit technology enabled a reduction in the oriented to rotate drilling ratio and an associated increase in the overall rate of penetration (ROP). It can be concluded that the substitution of 4 ¾" drilling equipment for 3 ½" in the 5 ½" hole section, increased the drilling efficiency between 30-50% according to field data obtained in Ukraine. The modified 4 ¾" PDM combined with long gauge bit technology has the potential to improve 5 ½" hole drilling performance in other locations. Following a structured planning process using State-of-the-art BHA modelling software suite enabling the evaluation of the significant forces that act in the drilling assembly and so significantly reducing the risks associated with exceeding the original design limits of the assembly. By improving the mechanical performance of the drilling assembly in a 5 ½" hole, new territory for drilling engineers and design engineers is now available to increase the drilling performance in slim wellbores.

HORIZONTAL DRILLING IN AUSTRALIA: THREE CASE HISTORIES

1991 ◽  
Vol 31 (1) ◽  
pp. 354
Author(s):  
Russell McNicoll
Keyword(s):  
Oil And Gas ◽  
Design Parameters ◽  
Horizontal Drilling ◽  
Assembly Design ◽  
Oil And Gas Fields ◽  
Bottom Hole ◽  
Directional Control ◽  
Bottom Hole Assembly ◽  
Gas Fields ◽  
Drilling Time

Three horizontal wells with horizontal sections of up to 331 m were drilled successfully during the development of the marginal North Herald and South Pepper oil and gas fields, which have relatively thin oil columns (6 to 12 m) at a depth of some 1200 m sub-sea. A steerable motor system was used to maintain directional control within the design parameters. This system proved to be successful from the start and no major changes to the bottom hole assembly design were required to drill all the wells. Average drilling time including running and setting the seven inch liner amounted to 12 days. The wells were tested with rates up to 7500 BOPD through a one inch choke.

Vibrations Increase Available Power at the Bit

1985 ◽  
Vol 107 (1) ◽  
pp. 138-141 ◽  
Author(s):  
D. W. Dareing
Keyword(s):  
Penetration Rate ◽  
Fatigue Loading ◽  
Vibration Energy ◽  
Assembly Design ◽  
Positive Side ◽  
Drilling Equipment ◽  
Bottom Hole ◽  
Dynamic Forces ◽  
Bottom Hole Assembly ◽  
Rotary Speed

Drillstring vibrations are generally considered to be detrimental to downhole drilling equipment because they produce cyclic or fatigue loading. Tool joint failures, tubular washouts, and bit breakage are often fatigue related. On the positive side, dynamic forces applied to roller cone rock bits have the potential to increase penetration rate. This paper quantifies the available vibration energy at the bit and shows how to control the level of energy through bottom hole assembly design and rotary speed.

Engineered Bottom Hole Assembly Design and Equipment Selection Criteria Prove To Be Key Factors in a Challenging Drilling Environment

2001 ◽  
Author(s):  
Graham R. Stronach ◽  
Gerre S. Voden ◽  
Jeffrey S. Hubbard ◽  
C. Michael Ming ◽  
J. Craig Northcutt
Keyword(s):  
Selection Criteria ◽  
Key Factors ◽  
Equipment Selection ◽  
Assembly Design ◽  
Bottom Hole ◽  
Bottom Hole Assembly

Hydraulic Workover Unit Utilization for New Well Openhole Drilling with Directional Motor and Logging-While-Drilling Bottom-Hole-Assembly in M Area

2021 ◽  
Author(s):  
Buna Rizal Rachman ◽  
Bonar Noviasta ◽  
Timora Wijayanto ◽  
Ramadhan Yoan Mardiana ◽  
Esa Taufik ◽  
...  
Keyword(s):  
High Speed ◽  
Site Preparation ◽  
Hole Drilling ◽  
Drill Bit ◽  
Directional Drilling ◽  
Bottom Hole ◽  
Drilling Method ◽  
Bottom Hole Assembly ◽  
Space Limitation ◽  
Logging While Drilling

Abstract Achieving a number of well targets in M Area is an important objective for MK, one of the oil and gas operators in Indonesia. An economic challenge is present due to marginal gas reservoirs in shallow zone. The conventional swamp rig unit requires significant costs for site preparation work and in some cases no longer fulfils the economic criteria. The objective was to drill the same one-phase well (OPW) architecture as the swamp rig normally drills, but at lower costs using a hydraulic workover unit (HWU). Drilling the 8½-in hole section OPW architecture using HWU was challenging, not only on the equipment rating and capability, but also on the deck space limitation part. The fit-for-purpose directional and logging-while-drilling (LWD) system was utilized in this project consisting of customized low-torque excellent hydraulics drill bit design, a positive displacement motor (PDM) with aggressive bend setting to achieve directional objective (with max 3.8°/30-m dogleg severity), annular-pressure-while-drilling (APWD) measurement to ensure equivalent circulating density (ECD) is maintained, and combined electromagnetic propagation resistivity and sonic slowness measurement coupled with high-speed telemetry measurement-while-drilling (MWD) tool to get an accurate and timely formation evaluation. The HWU deck space limitation was solved by implementing a single combined directional drilling (DD), MWD, mudlogging cabin, in addition to the remote operation control implementation to further reduce carbon footprint. Five wells were drilled safely and successfully in this campaign. Drilling efficiency improved with up to 109% ROP increase as compared to the first well, showing the progressive learning curve and excellent teamwork from all involved parties. The directional bottom hole assembly (BHA) was capable of delivering up to 4–5°/30-m dogleg, not only achieving the directional objective, but also penetrating the reservoir targets with tight tolerances. The drill bit delivered very good ROP, reaching 60.4 m/h (about 66% of average OPW ROP achieved by swamp rig). This campaign also successfully reduced the overall site preparation cost by up to 30%, enabling MK to drill wells that were initially not feasible to be drilled using swamp rig within the time frame and budget. Thanks to the success, this new method is currently under study for industrialization. The HWU drilling campaign provided a valuable learning experience, is considered as a proven drilling method, and served as a benchmark for other operators in Indonesia. HWU drilling has proven to be an efficient drilling method and capable of delivering the one-phase-well. This paper presents a unique case study of new well open hole drilling with the HWU and its applicability in M Area. Most studies in the past were HWU drilling in re-entry or sidetrack cases.

Horizontal Well Casing Design Optimization & Implementation Case Study: Vibrations Management Through Enhanced Bottom Hole Assembly Design

2019 ◽  
Author(s):  
Nikolay Abaltusov ◽  
Anton Ryabov ◽  
Aleksandr Dankov ◽  
Elvir Zaripov ◽  
Dmitriy Grishin ◽  
...  
Keyword(s):  
Design Optimization ◽  
Horizontal Well ◽  
Assembly Design ◽  
Bottom Hole ◽  
Bottom Hole Assembly

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.

scholarly journals The Study of the Interaction of Different Arrangements of the Bottom-Hole Assembly with the Bottomhole and the Borehole Wall

2019 ◽  
pp. 58-68
Author(s):  
Ya. M. Kochkodan ◽  
A.I. Vasko
Keyword(s):  
Differential Equations ◽  
Contact Point ◽  
Point Contact ◽  
Drill String ◽  
Borehole Wall ◽  
Deviation Angle ◽  
Technological Parameters ◽  
Bottom Hole ◽  
Anisotropy Index ◽  
Bottom Hole Assembly

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.

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