Increasing drilling efficiency and performance are key factors for determining whether or not a new play is viable for drilling. Although several factors affect drilling cost, one key element in reducing cost is reducing drilling time by increasing the rate of penetration. This is accomplished by changing the way a drill bit interacts with the formation and analyzing different ways to overcome the factors that limit drilling performance.New performance drilling tool designs are brining conventional mud motors into the next generation with performance driven technology. This technology features the latest generation of performance elastomers with a new energy distribution system which enhances the rock failing properties of the attached bit. This is achieved by applying both axial and torsional loading to the bit at the same time.Conventional motors are limited by torsional loading which correlates to the differential pressure a power section can hold before it stalls. The interaction between the bit and the rock correlates to this stall pressure of the power section used. The new performance technology takes this torsional load and merges it with the axial load created by the weight of the drill string, which it then oscillates axially. The combination of axial and torsional oscillating movement amplifies the cutting interaction of the bit to help overcome the compressive strength of the formation being drilled.Due to the unique design and different available configurations, this technology is compatible with both roller cone and fixed cutter bit designs. This design allows for constant contact between the bit and formation, reducing any bit bounce or stick slip which could reduce drilling efficiency. Along with increasing bit performance it also helps reduce weight stacking by reducing friction caused from interaction between the BHA and formation. This has proven to help with weight transfer to the bit and to reduce motor stalling, thereby improving directional control.
Drilling the Taoudenni Basin in Mauritania has posed a costly and time consuming challenge for operators looking to develop the basin economically. The formation's compressive strength limits the bit selection to heavyset PDC bits or hard rock roller cone insert bits due to their abrasive composition. One way to increase the effectiveness and drilling efficiency is to add a percussion force, increasing the axial energy, along with a hybrid PDC bit with PDC cutters and impregnated diamond material on the blades and secondary cutting structures.The main similarity between fixed cutter hybrid bits and roller cone bits is that both incorporate a similar means of energy transfer when used with a positive displacement motor. Axial weight from a drilling rig is applied while a hydraulic motor turns the bit at different speeds. A proposed improvement to this drilling system would be a new energy distribution system that induces axial oscillations and percussion force while still applying the same weight and torsional energy as previous systems.The system combines the torsional power of a conventional positive displacement motor with a high frequency axial pulse created by a mechanical action. The torque is still transferred directly to the bit and 100% of the hydraulic flow is utilized by the bit nozzles. The mechanical lifting and falling action creates a rapid variation in weight on bit (WOB), allowing the bit's depth of cut to fluctuate while overcoming different stresses. The percussion force created after each downward stroke, along with weight on bit variations, lead to increased rates of penetration (ROP).This system has already been utilized on two wells in Mauritania, drilling a variety of formations with PDC, hybrid fixed cutter and roller cone insert bits. This paper will focus on the 8½Љ interval, drilling the Atar Group and Jbeliat Teniagouri formations. These formations consist of sandstone, shale interbedded with siltstone, dolerite and pyrite. Confined compressive strengths range from 20 to 30kpsi in top section to 60kpsi in lower intervals where dolerite appears. This new technology increased ROP by more than 52% and interval drilled by over 100% through these intervals.
Drilling efficiency is a key factor in determining the viability of potential hydrocarbon plays throughout the world. Pushing our capabilities for speed and accuracy changes the evaluation of value that not only operators place on emerging and potential plays, but also the evaluation that countries place on the value of their available natural resources. Fundamental drilling challenges such as formation hardness, reactive torque, tortuosity, and abrasive formation types continue to inhibit our ability to seek out less conventional reserves.Reaching our targets faster and at a reduced overall cost allows us to expand the breadth of viable drilling opportunities in all regions while accessing additional value previously out of reach in existing plays. Today we are pushing current technology to the threshold of its capabilities with longer laterals and deeper targets in more complex well profiles. Without a step change in technology, we are nearing our maximum potential.A simple yet revolutionary technology has added new life to existing drilling technologies and is now addressing some of the fundamental drilling dynamics that currently limit our drilling efficiency and restrict our ability to reach for the next level of performance. This technology works in conjunction with existing drilling systems to amplify the vertical forces applied to the bit. By varying this amplification at specific frequencies, more efficient failing of the formation can be achieved. Increased ROP well above 50% has been achieved with consistent results over offset data with reduction in reactive torque and stick slip events. This paper details how by increasing cutting efficiency, a major operator has greatly extended bit life resulting in an increase in interval drilled lengths of as much as 125%.
Drilling the Severnaya Truba Field in Aktobe, Kazahkstan, has proved to be a costly and time consuming challenge for operators trying to maximize profits. The formation is typically drilled with roller cone bits that take multiple runs to complete an interval. To increase effectiveness and drilling efficiency, a hydraulically powered percussion drilling system along with a fixed cutter PDC bit were added.In place of a conventional drilling system, a new energy distribution system was introduced that would induce axial oscillations and percussion impacts while applying the same weight and torsional energy to the bit. In combination with a drilling fluid powered percussion hammer (FPPH), a fit for application polycrystalline diamond compact (PDC) bit with depth of cut (DOC) control features was used to minimize the exposure of the cutting structure and prevent breakage.The system combines the torsional power of a conventional positive displacement motor with a high frequency axial pulse created with each rotation. The torque is transferred directly to the bit and 100% of the hydraulic flow is utilized by the bit nozzles to maintain hole cleaning and keep PDC cutters cool. The mechanical lifting and falling action creates a rapid variation in weight on bit (WOB), allowing the bit's depth of cut to fluctuate while overcoming different stresses. These variations, along with the percussion pulse created with each stroke, lead to increased rates of penetration.This system has been used throughout the world on a variety of formations, using both PDC and roller cone insert bits. This paper will focus on an 8½ in interval drilling operation in the Severnaya Truva field, located 60 km from Zhanazhol field in Kazakhstan. The formations consisted of soft to medium siltstone, red/grey clays, sandstone, hard cemented dolomite, limestone, and very dense clay stone. This new technology proved to increase both ROP and interval drilled, saving seven days of drilling compared to offset wells.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.