TECHNICAL PAPERS

IADC/SPE-208747-MS New-Generation Geothermal Wells – How the Upstream Oil and Gas IndustryCan Bring Its Experience to Bear

2022 SPE/IADC Drilling Conference and Exhibition, Galveston, Texas, USA

As renewables are forecast to take a larger and larger slice of the energy mix going forward, the upstreamoil and gas industry needs to look at whether and how it can be involved with these new sources of energy in order to maintain its share of the energy mix. Providers of services and technology to the industry should be thinking about how they might be able to apply their skills and capabilities in other, adjacent industries and should begin to think of themselves as energy service companies and not oilfield service and oilfield equipment supply companies.

As the world searches for and attempts to bring on alternative sources of energy, the “holy grail” is a renewable energy source that can provide 24/7 baseload power without releasing greenhouse gases. Wind and solar both have issues with intermittency and therefore with capacity, and will require additional storage capacity – for example, batteries – in order to be able to deliver baseload. More traditional energy sources suffer from significant greenhouse gas emissions. Geothermal is currently the only source of energy which has the potential to provide clean power at scale and in a way that can provide uninterrupted baseload for an electrical grid – without the requirement for storage and the unnecessary consumption of resources this would entail. Serendipitously, geothermal drilling also has many similarities with drilling for oil and gas.The paper will review how geothermal installations are evolving beyond traditional hydrothermal wells and how they will include closed loop systems which seek to extract heat, and not hot water or steam, from the Earth.

This paper describes the various types of new geothermal systems that have been proposed with some commentary on what has been achieved to date. It identifies both similarities and differences between the various well types required for these “unconventional” geothermal systems and the many different challenges in terms of well design and construction that our industry has developed, and perfected over more than 100 years. The similarities that are identified can be thought of as near-term opportunities for the oil and gas drilling industry to apply its skills, technologies and people to this new and growing sector.

The differences can be thought of as challenges that our industry will have to overcome in order to be a valuable part of the inevitable transition that will take place in the near future. 

SPE-207342-MS Optimizing Directional Drilling While Simultaneously Maximizing the Whole Life Value of the Well

2021 ADIPEC, the Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE.

Increasingly complex wells and longer laterals present new challenges for wellbore placement and wellbore quality. There is a growing understanding of the impact of well placement and wellbore quality on the overall value of the well and on the economics of completions and production. This paper looks at how requirements have evolved and will evolve beyond simply “getting to TD” as quickly as possible and how emerging technologies can help.

There is already an undercurrent of opinion that completions and production are sometimes compromised to maximize rate of penetration, but with some controversy about the exact value and how easy it is to attribute cause. This paper reviews how directional drilling practice has evolved over 100 years, and how the wellbore quality that results from the directional drilling process can be a driver for the overall value of the well. Specifically, it draws on a number of key references to examine how tortuosity doesn’t just have an influence on drilling but also how it can adversely impact completions, reliability of production equipment and even production rates. The paper proposes that we consider the whole-life value of the well as a key performance indicator as we drill. It emphasises that we must cease to focus solely on rate of penetration and the depth-time curve.

The paper shows, with examples, how modern directional drilling systems can address tortuosity and improve wellbore quality. It presents an unbiased view of the industry from an independent viewpoint, exploring how directional drilling has been partially automated over the years and examining the state of the art in current automated directional drilling systems. It proposes the need for a modern directional drilling system not just in terms of drilling parameters but also in terms of automation of geometric and, ultimately, geologic aspects of directional drilling.

The paper is intended to break down the silos that can exist between drilling, completions and production functions, and to help the industry to think about the long-term consequences of performance when specifying future directional drilling equipment.

SPE-203404-MS Innovation in a New Normal – How Can the Upstream Industry Develop New, Fit-For-Purpose Technology?

Presented at the virtual 2020 ADIPEC, the Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, UAE.

The upstream oil and gas industry suffered an unprecedented dual shock in 2020. Suppression of demand caused by the global Covid-19 pandemic combined with oversupply caused by competition for production market share between major suppliers across the globe. Although the world that will emerge in 2021 is hard to predict, it is very likely that it will be different from the past. It is equally likely to change much more quickly, therefore needing new ways of developing and introducing new technology-based products and services. This paper introduces the dichotomies that will emerge. In particular the industry will need to be focused in order to deliver technology on time, at the same time being flexible in response to rapid changes. It can be challenging to meet both of these apparently conflicting requirements. By exploring the principles of innovation theory from a number of perspectives, this paper offers insights and suggestions to help the industry develop the highly efficient technological solutions it will need to thrive in 2021 and beyond in the face of significant restrictions on financial and other resources. It also describes the impact of stakeholder interests, including the pressures arising from environmental, social and governance (ESG) issues, which will not go away despite the shock to the industry that 2020 brought, and suggests how these may be met while developing effective new technology. The paper uses real-world examples, including examples from other industries, to describe strategies for product and service development, and business model adjustment. It concludes with a toolbox of ideas and techniques that should be broadly applicable across the upstream industry.

SPE-194170-MS A Paradigm in Rotary Steerable Drilling – Market Demands Drive a New Solution

2019 SPE/IADC Drilling Conference and Exhibition, The Hague, Netherlands

This paper reviews how the Rotary Steerable System (RSS) market has changed over the last two decades. It explores current market forces; specifically the shift in RSS philosophy resulting from ever-improving motor steerable technology. It describes how the need for longer laterals with minimal tortuosity, maximum drilling efficiency, reduced risk of unplanned events, and elimination of AFE overspend, along with the paradigm shift in the directional drilling market seen since 2014, drove the specification for a new-generation RSS tool. The paper describes the development of a new RSS with a topology and control concept that allows full proportional control of bias from a fully rotating, push-the-bit tool, with the ability to “turn off” any bias during operations where side force is undesirable and to minimize potential tortuosity. It describes how the design team focused on modular design and rapid turn around of tools, in order to maximize utilization and efficiency. Field-test results are included, which demonstrate build and turn at up to 10°/100 ft. and the ability to drill accurate lateral sections. Field results also include the use of ultrasonic imaging while drilling to investigate hole quality.

SPE-156961-MS Departure From the Norm in Polycrystalline Diamond Bit Design Allows Significant Performance Gains in Highly Erosive and Abrasive Formations

2012 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA

PDC drill bits have grown from niche to mainstream products by gradual, subtle evolutions in design and materials technology. Occasionally, there have been more dramatic step changes in design or materials that have launched PDC bits into new applications. This paper will talk about such a step change: the design, manufacture and application of a contiguous blade of polycrystalline diamond. Rather than blades made up from individual cutters, as with a conventional PDC bit design, this bit has full-length, contiguous polycrystalline diamond coverage, without gaps between cutters on each blade. The advantages of this arrangement are many. Most obvious is the ability to drill erosive and/or abrasive formations without erosion. Often PDC bits, especially lighter set bits, can lose steel or matrix body material between the cutters due to erosion or abrasion, and this can be life-limiting. With no gaps between the cutters, this ceases to be a problem. Other possibilities include: bits for more conventional formations where a contiguous blade can be used instead of backup cutters, enhancing ROP and stability (Maw 2012). This represents a step change in bit design with the potential to redefine bit design across the applications spectrum.

This paper details some of the problems with the currently accepted PDC design paradigm, and proposes a novel solution to them by changing it. The hurdles in the way of making the concept a reality and their solutions are described, relating to new concepts in bit design, cutter selection, and new manufacturing process. The testing methodology used to prove the concept in the oil sands in northern Alberta, Canada, as well as the test results are presented. Finally, future planned developments based on the apparent advantages of the invention are forecast.

SPE-157777-MS Paradigm Shift in Polycrystalline Diamond Bit Design for Canadian Heavy Oil Sands

2012 SPE Heavy Oil Conference, Calgary, Alberta, Canada

PDC drill bits have grown from niche to mainstream products by gradual, subtle evolutions in design and materials technology. Occasionally, there have been more dramatic step changes in design or materials that have launched PDC bits into new applications. This paper will talk about such a step change: the design, manufacture and application of a contiguous blade of polycrystalline diamond. Rather than blades made up from individual cutters, as with a conventional PDC bit design, this bit has full-length, contiguous polycrystalline diamond coverage, without gaps between cutters on each blade. The advantages of this arrangement are many. Most obvious is the ability to drill erosive and/or abrasive formations without erosion. Often PDC bits, especially lighter set bits, can lose steel or matrix body material between the cutters due to erosion or abrasion, and this can be life-limiting. With no gaps between the cutters, this ceases to be a problem. Other possibilities include: bits for more conventional formations where a contiguous blade can be used instead of backup cutters, enhancing ROP and stability. The paper describes how various challenges were overcome: bit design; materials selection; polycrystalline diamond blade manufacture. It will also discuss applications of this technology in bits specially designed for the oil sands in northern Alberta, Canada, focusing on:

• Dull condition enhancement as a result of avoiding cross-blade erosion and abrasion
• Polycrystalline diamond blade durability
• The effect of a smaller number of contiguous blades on ROP and PDC bit economics.

This represents a step change in bit design with the potential to redefine bit design across the applications spectrum.

SPE-118298-MS True Matching of Bit and Multidiameter String Tools Delivers Optimized Drilling Performance

2009 SPE/IADC Drilling Conference and Exhibition, Amsterdam, Netherlands

The increased use of hole opening tools remote from the drill bit has led to a critical need to understand the interaction between the drill bit and the hole opening tool itself. Problems that can result from improper matching include vibration, inability to open hole, mechanical damage to string tools or to the bit, and sub-optimal drilling performance.

This paper explores the theoretical relationship between bit and reamer and modeling the relative agressivity and stability of both tools, building on already established indices for predicting and comparing the performance of bits. It also considers stabilization of the hole opening tool using both concentric and eccentric devices. It describes theoretical modeling of the vibration behavior of the assembly. It then describes field validation of the above using a unique downhole data recording device, located at various key points in the BHA and drill string.

Finally, the paper will review a number of case studies and demonstrate a linkage between the theoretical analysis, the measured validation, and actual field results. These relate to a variety of directional applications including vertical rotary, directional motor and rotary steerable, and demonstrate reduced vibration, improved hole quality and hole opening performance, superior penetration rates, and overall significantly reduced drilling costs.

SPE-116173-MS Testing of New PDC Cutter Edge Geometry Doubles Penetration Rate and Reduces Torque

2008 SPE Annual Technical Conference and Exhibition, Denver, Colorado, USA

A new edge preparation of Polycrystalline Diamond Compact (PDC) cutters has been developed to target applications where either weight or torque is limited. This paper describes the geometry, which differs considerably from existing thermostable product.

Initial testing at atmospheric conditions in a drilling laboratory shows a 30% reduction in torque and a 100% increase in penetration rate when compared to conventional cutter geometry. Secondary testing was conducted with drill bit designs at a non-commercial test facility. In this controlled environment, designs with new cutter edge geometry were compared directly to those with conventional cutters. By using the same drill bit cutting structure and parameters, any difference in torque and penetration rate was solely dependent upon the cutter geometry. Additionally, to quantify any effects caused by torsional or lateral vibration, a downhole dynamics recorder was used to gather data at a high frequency sample rate.

Performance studies are presented for a variety of applications from around the world but focusing on applications within the US Rockies. They compare direct offset runs against conventional geometry cutter designs. Results demonstrate that the new geometry delivers footage and ROP equal or greater than the best field offsets.

The increased penetration rate and reduced torque provided by this geometry result from more efficient failure of the rock. This provides reduced Mechanical Specific Energy and improved drilling efficiency, thus reducing drilling costs for the operator. This is a significant step change in PDC cutter technology, dramatically increasing fixed cutter drill bit performance.

SPE-108248-MS PDC Bit Designed for High Lateral and Torsion Stability Significantly Improves Rotary Steerable Performance in the Middle East

2007 SPE Middle East Drilling Conference, Cairo, Egypt

Historic performance in slim hole rotary steerable (RS) applications in the Middle East was held back by severe torsional and lateral vibration issues. A new family of slim hole polycrystalline diamond compact (PDC) bit designs, specifically matched to the rotary steerable systems (RSS) used, has resulted in a dramatic improvement in performance.

The use of mathematically modeled bit performance indices has resulted in a significant improvement in RSS and bit performance while drilling harsh environments in the Middle East where lateral and torsional vibration events are severe. The bit design in question was further optimized by including design characteristics specifically targeted at reducing torsional events. Further, bit hydraulics have been optimized to minimize erosion and maximize borehole quality while matching system operation requirements.

Case studies are presented clearly demonstrating runs with superior performance in the Kingdom of Saudi Arabia (KSA). The field trials clearly demonstrated that significant reduction in torsional vibration and improved side cutting led to superior dogleg achievement. Improvement in lateral stability and resultant bore hole quality led to extended bit and tool life, thus notably improving penetration rate.

The paper concludes that significant performance increases can be achieved by matching the bit design to the RSS, the well geology and the well trajectory. This has resulted in advances in slim hole drilling.

SPE-102287-MS Improved Optimisation of Bit Selection Using Mathematically Modelled Bit-Performance Indices

2006 IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition, Bangkok, Thailand

Despite the development of models describing Polycrystalline Diamond Compact (PDC) bit performance, bit selection is often made on the basis of visible, geometric features.

Bits can now be modelled routinely and described in terms of their technical interaction with the drilling assembly and the formation. Selection on the basis of modelling and this interaction is novel and valuable, and will make for more consistent selection and improved performance.

A new set of performance indices is presented for PDC bits. These are derived from a sophisticated mathematical model and describe performance in terms of:
ROP – Rate of Penetration, or how fast the bit will drill for a given Weight on Bit (WOB)
Durability – how resistant the bit is to abrasive wear
Stability – how resistant the bit is to lateral vibration
Steerability – how the bit responds to side forces and therefore how steerable it is on Rotary Steerable Systems.
Once the relative importance of each index is established, the optimal bit for the specific application can be selected.

A specialist interface is presented for Rotary Steerable Systems. Using this, the user can input system type (from the variety of systems available) and well profile, and the software will create a list of bits ranked by decreasing suitability, based on a variety of factors including some aspects of bit geometry but primarily mathematically modelled response.

The paper presents results from pilot studies and demonstrates a scientific and rational approach to bit selection – giving not only improved but also more consistent and reliable results.

SPE-102067-MS Faster and Longer Bit Runs With New-Generation PDC Cutter

2006 SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA

A new process for manufacture of Polycrystalline Diamond Compact (PDC) cutters creates a wrapped thermostable region across the face and around the periphery of the diamond compact. This differs significantly from existing first-generation thermostable product as the treated region has complex geometry in three dimensions. This paper describes the new geometry of the cutters and shows how the thermostable region supports the cutter as it slowly wears. It also shows how the onset of wear into the tungsten carbide substrate behind the diamond layer is delayed significantly.

Laboratory test results show a 270% improvement in abrasion resistance over premium PDC material and field case studies show how the new cutter type has saved money while drilling and allowed PDC bits to drill sections that previously required multiple bit runs.

Case studies are presented from a variety of applications around the world including hard and interbedded formations and abrasive sands. They compare direct offset runs with existing, first-generation thermostable data.

The new-generation thermostable cutter stays sharper, for longer, than either the first-generation thermostable cutter or previous non-thermostable PDC material. It will allow development of lighter set and more aggressive bit designs able to set new standards in speed, steerability and stability without having to sacrifice durability in the design.

New cutting material developments are at the forefront of the ongoing improvement of PDC bits. This is a significant development that shows a step change in cutter and bit performance. It allows for the realization of a new generation, not just of cutters, but also of bit designs.

SPE-29382-MS Steerable Rotary Drilling with an Experimental System

1995 IADC/SPE Drilling Conference, Amsterdam, Netherlands.

Some of the needs in directional drilling of extended reach and horizontal wells are discussed. It is forecast that Steerable Rotary Drilling (SRD) will meet some of these needs, providing economic benefits. Known options for an SRD system are briefly discussed. The system devised uses synchronous polyphase modulation of bias from a mechanism connected to, and rotating with, the drill bit, powered by drilling fluid and controlled by a directional sensor package, the orientation of the latter being independent of BHA rotation, stabilized and controlled. This scheme meets structural requirements while being capable of development for a wide range of hole sizes The concept was proved by drilling an interval of 638m (2092ft) with an experimental SRD system. Deviation, while rotating, was controlled at rates up to 8.50/30m (8.60/100 ft) to change elevation up/down and azimuth left/right. The system was successful with both PDC and roller cone bits and the deviation rate vector was largely independent of bit weight. rotary speed and penetration rate. The drilling trials have provided data for a product aimed particularly at extended reach and horizontal drilling. Economic benefits are expected by saving time and by improving directional control.

SPE-23868-MS An Analysis of the Field Performance of Antiwhirl PDC Bits

1992 IADC/SPE Drilling Conference, New Orleans, Louisiana, USA

“Bit whirl”, the backwards whirling motion of polycrystalline diamond compact (PDC) drill bits, has been identified as a significant contributory factor in the premature failure of PDC bits in the field. Two SPE papers have discussed bit PDC bits in the field. Two SPE papers have discussed bit whirl and the testing of various potential solutions, and one described the field testing of PDC bits modified to produce a “low friction gauge”. This paper describes the design and subsequent testing in the laboratory and then in the field of a PDC bit designed from scratch to resist backwards whirling motion by incorporating various design features including the “low-friction gauge” concept described by Warren et al (described below as an “Antiwhirl bit”). It details the importance of the magnitude of the lateral-component of the resultant cutting force on the bit and the angular extent of the bearing pads that react with this force, and describes and explains the directional behaviour of Antiwhirl bits in the field.