Defining Design and Optimization Method: Dynamic Simulation Model Produces Integrated BHA Solutions for Efficient Wellbore Delivery

Chen, Wei; Shen, Ying; Harmer, Richard; Rawlins, Sheldon Andre; Dong, Yinan; Chen, Rongbing

doi:10.2118/173008-ms

Cited by 18 publications

(1 citation statement)

References 10 publications

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“…The simulation modeled the interaction between the cutting structure and formation drilled using rock mechanics derived in the lab. The simulation results are the drilling behavior of the whole drill string components, including the vibrations, stress, torque, and even ROP prediction [6].…”

Section: Advanced Drilling Dynamic Simulation Overviewmentioning

confidence: 99%

The Effects of PDC Cutter Geometries to the Drilling Dynamics in Various Geothermal Rocks: A Comprehensive Study Using Advanced Drilling Dynamics Simulation

Mardiana¹,

Pasaribu²

2022

IOP Conf. Ser.: Earth Environ. Sci.

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Polycrystalline Diamond Compact (PDC) bit has been used widely in drilling operations since a long time ago. However, the utilization of this bit in Indonesia’s geothermal drilling has just recently started in 2016, thanks to the rapid development of PDC cutter grades and shapes in the last decade. Prior to that, the geothermal drilling operation relied on Tungsten Carbide Insert (TCI) bit to drill the hard formations. The crushing action of the insert bit is very durable to remove the rocks. However, the seal and bearing limit the life of these bit types, causing multiple bit runs in a long drilling section. PDC bit offers longer drilling periods if the cutters are still in good condition. However, the nature of geothermal formation usually consists of hard rocks with fractures that can reduce the durability of the conventional flat PDC cutters. To overcome this weakness and optimize drilling operation,. Instead of having a flat surface, new PDC cutters have different 3D shapes. Each has different benefits: improving cutter strength against impact, increasing aggressiveness and depth of cut, or enhancing wear resistance towards abrasive formations. Advance drilling dynamics simulation helps analyze which cutter types will be more suitable for different geothermal rocks characteristics. The simulation is based on 4D Finite Element Analysis, which models the interaction between the cutting structures and the drilled formation. The result shows the dynamic drilling response of each cutter on different rocks, including the generated vibration, the cutter’s depth of cut distribution on the bit face, and the potential wear pattern on the bit. This paper then discusses which cutter and PDC bit type will be more beneficial for geothermal drilling based on the bit aggressiveness and durability to optimize the drilling operation.

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Section: Advanced Drilling Dynamic Simulation Overviewmentioning

confidence: 99%

The Effects of PDC Cutter Geometries to the Drilling Dynamics in Various Geothermal Rocks: A Comprehensive Study Using Advanced Drilling Dynamics Simulation

Mardiana¹,

Pasaribu²

2022

IOP Conf. Ser.: Earth Environ. Sci.

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Integrated Efforts to Understand and Solve Challenges in 26-in Salt Drilling, Gulf of Mexico

Shi

Durairajan

Harmer

et al. 2016

Day 1 Wed, September 14, 2016

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Operators of Gulf of Mexico (GOM) wells frequently reported overtorque issue of bottomhole assembly (BHA) connections when drilling the 26-in. section through salt. Such overtorque often leads to costly tool damage beyond repair (DBR), additional trips, and high nonproductive time (NPT). The average DBR cost per BHA can be as high as USD 1 million. Combined with a complete BHA roundtrip, it can easily cost more than USD 3 million for operators if such failure happens. This has been a problem for several years and has caused significant damage: In 2014, of 15 26-in. PDC bit runs in salt, 40% had overtorque connections and 20% led to DBR. This paper discusses how an integrated multidisciplinary team identified the root cause of and the solution to the overtorque problem. Torsional vibration was believed to be the cause of such failure. Comprehensive drilling dynamics simulation software that is based on empirical bit design knowledge was used to design a new bit to reduce the vibration. A newly developed high frequency downhole recording tool used in the 26-in. section recorded high-frequency torque, acceleration, and RPM fluctuation downhole. This dataset became the key to understanding the downhole vibration in detail because it provided information that cannot be acquired by a traditional MWD tool. Field-recorded data were fed into drilling dynamics simulations to accurately calibrate the drilling dynamics model. The simulations resembled downhole drilling conditions and clearly identified the root cause. The simulations precisely predicted the torque along the entire drillstring and identified why overtorque is present in only a certain part of the drillstring. The calibrated model was used to compare old and new bit designs. The newly designed bit showed much lower torque amplitude with similar torsional vibration frequencies. The simulation indicated that the newly designed bit can significantly alleviate the overtorque issue. Implementation of the new bit mitigated the overtorque issue immediately. As of May 2016, there have been 18 runs with the new bit. Only one run had a slight overtorque issue whereas the rest showed no sign of overtorque connections. DBR and NPT related to overtorque were eliminated. As a byproduct, the average on-bottom rate of penetration increased by 9%. This case demonstrates the effectiveness of the integrated approach to solving drilling challenges.

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Continuous High Frequency Measurement Improves Understanding of High Frequency Torsional Oscillation in North America Land Drilling

Zhang

Shen

Chen

et al. 2017

Day 2 Tue, October 10, 2017

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Bit and bottom hole assembly (BHA) rotational speed oscillation is often encountered in North America land drilling applications. One common type of rotational speed oscillation is the well-known stick-slip, with speed variation at a frequency that is close or lower than the fundamental torsional natural frequency of the drillstring (usually less than 1Hz). Another commonly encountered rotational speed oscillation confirmed by the authors' recent studies is the high frequency torsional oscillation (HFTO), with a frequency ranging from 10's to over 100 Hz. This paper will discuss new findings on HFTO. Most of the commercially available downhole measurement tools have no difficulty picking up the low frequency stick-slip, but lack bandwidth to detect HFTO. Also it is rarely observed from the surface instruments because high frequency torsional wave can be dampened quickly when it is transferred along the drillstring. Hence, HFTO could be misinterpreted as smooth drilling until tool failure or damage occur. To understand the mechanism of HFTO, a series of downhole tests were conducted in North America land with different BHA setups and applications. An advanced downhole measurement tool was placed in the BHA to continuously record tri-axial acceleration and rotational speed at 1024 Hz sampling rate. After extensive analysis performed on the downhole high frequency data, we present in this paper many interesting findings. HFTO shifts frequency depending on different downhole conditions. There is a strong correlation between the surface parameters (RPM and SWOB) and the occurrence of HFTO. The excitation of HFTO is also related to the formation. 3D transient drilling dynamics simulation confirms the factors that increase the risk of HFTO. Based on this study, we provide recommendations to downhole measurements for capturing HFTO. With real-time HFTO detection, drilling parameters can be adjusted to reduce the chance of HFTO to avoid premature tool failures. We also provide insights for new tool development to obtain better tool life by eliminating weak spots and perform more robust measurements by selecting better sensor locations, etc. With the help of 3D transient dynamic modeling, we can gain better understanding of HFTO mechanisms through numerical simulation, making it possible to plan the BHA effectively and select drilling parameters to avoid HFTO.

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Defining Design and Optimization Method: Dynamic Simulation Model Produces Integrated BHA Solutions for Efficient Wellbore Delivery

Cited by 18 publications

References 10 publications

The Effects of PDC Cutter Geometries to the Drilling Dynamics in Various Geothermal Rocks: A Comprehensive Study Using Advanced Drilling Dynamics Simulation

The Effects of PDC Cutter Geometries to the Drilling Dynamics in Various Geothermal Rocks: A Comprehensive Study Using Advanced Drilling Dynamics Simulation

Integrated Efforts to Understand and Solve Challenges in 26-in Salt Drilling, Gulf of Mexico

Continuous High Frequency Measurement Improves Understanding of High Frequency Torsional Oscillation in North America Land Drilling

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