Single Cutter Testing – A Key for Pdc Bit Development

Zijsling, Djurre

doi:10.2118/16529-ms

Cited by 49 publications

(23 citation statements)

References 5 publications

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] The number of factors hints at the complexity of the bit/rock interaction, something which is compounded by interdependence and nonlinearity in some of these effects. 6,7,11,15,18 Laboratory studies and modeling are however unraveling this complexity.…”

Section: Background To the Methodsmentioning

confidence: 99%

“…In permeable rocks for example, overbalance pressure influences ROP, 1 giving way to a dependence on bottomhole pressure as permeability decreases. [2][3][4] Overbalance pressure effects however are subject to dynamic influences, either via filtration effects on pore pressure in the bit/rock interaction zone, 5 or via stress effects on pore pressure around the wellbore. 6 Bit cleaning effects while drilling hydratable formations in water base drilling fluids ͑''muds''͒ may also override the effects of mechanical drilling parameters, so that rock mineralogy and mud chemistry are obviously significant factors.…”

Section: Background To the Methodsmentioning

confidence: 99%

“…8,10 In summary, rock properties that influence ROP include at least mineralogy, strength, density, porosity, and permeability. 2,3,5,8,9,11,14 Interdependence between mechanical and hydraulic drilling parameter effects may also be significant, meaning for example that the response of ROP to weight on bit ͑WOB͒, rotary speed and flow rate can depend on absolute values of these parameters. 7 Bit design effects are also not simple; differences in bit design effects on ROP with polycrystalline diamond compact ͑PDC͒ bits appear only to become significant when bit cleaning problems occur, or when cutters become worn.…”

Section: Background To the Methodsmentioning

confidence: 99%

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How to Improve Rate of Penetration in Field Operations

Fear

1999

SPE Drilling &Amp; Completion

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A method has been developed to identify which factors are controlling rate of penetration ͑ROP͒ in a particular group of bit runs. The method uses foot-based mud logging data, geological information, and drill bit characteristics, to produce numerical correlations between ROP and applied drilling parameters or other attributes of drilling conditions. These correlations are then used to generate recommendations for maximizing ROP in drilling operations. IntroductionTime spent drilling ahead is usually a significant portion of total well cost. In typical wells drilled by BP Exploration ͑BPX͒, this ''rotating time'' usually accounts for 10% to 30% of well cost. This means that the penetration rate achieved by the drill bit has considerable significance for drilling cost reduction.Despite this, the bit/rock interaction, and the ROP that results, is not well understood in detail. Other drilling phenomena, such as torque/drag modeling or directional behavior, are typically managed with the aid of validated, quantitative models. Such tools are conspicuously absent from planning or analysis of bit performance.Within drilling operations, uncertainty over expected ROP clouds decisions on which bit types and downhole tools to select to maximize ROP. That intuition is prominent in these decisions demonstrates the inability of drilling data or predictive models to provide anything more substantial.Against this background of commercial significance and technical difficulty, BPX is developing engineering methods to raise ROP. This paper describes one such method, and its application and benefits to one drilling operation.

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Section: Background To the Methodsmentioning

confidence: 99%

Section: Background To the Methodsmentioning

confidence: 99%

Section: Background To the Methodsmentioning

confidence: 99%

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How to Improve Rate of Penetration in Field Operations

Fear

1999

SPE Drilling &Amp; Completion

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“…Extensive research into improving the thermal stability of PDC cutters is on-going and focuses on improving the PCD material itself (Gent 2009;Plemons 2010;Sneddon and Hall 1988;Zhang 2012). However, detailed research into non-planar cutters provides an opportunity whereby some mechanisms that affect thermal breakdown can be addressed from a mechanical efficiency standpoint, thus supplementing any material development gains (DiGiovanni 2014;Feenstra 1984;Knowlton 1989;Zijsling 1987).…”

Section: Non-planar Cutter Designmentioning

confidence: 99%

Innovative PDC Drill-Bit Cutter Technology Leads to Performance Improvements in Western Desert, Egypt

Ismail

Stockey

DiGiovanni

et al. 2015

Day 1 Mon, September 14, 2015

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The ongoing drilling campaign for an operator drilling in Egypt's Western desert area involved drilling vertical and directional wells approximately 5,000-to 5,500-m deep. The application involved drilling through very hard and abrasive sandstones, and intercalations of shale, sand, silt and dense dolomite inter-beds of about 25,000 psi unconfined compressive strength (UCS). Historically, poly crystalline diamond compact (PDC) drill-bit showed inconsistent bit performance that included premature bit failure and low rate of penetration (ROP), resulting in costly bit trips to the surface.New and improved bit technology was required to improve the penetration rate and footage to reduce bit trips to the surface and improve the overall drilling performance. An in-depth study of the formation properties, wireline logs, drilling parameters and bit dull analysis was performed. Detailed analysis identified this application can benefit from running cutters with a non-planar cutting face on a field-proven seven-blade PDC bit frame. The bit was run on a Rotary Steerable System (RSS) coupled with a positive displacement motor (PDM) on top of the BHA to further improve the drilling efficiency and overcome any challenges.Upon deployment, the 8½-in bit design with the new 16-mm cutters with non-planar cutting structure combined with optimized depth-of-cut control, stability, hydraulics efficiency and balling prevention features led to improved performance when drilling the complex, hook-shaped well profile (where torque and drag were an issue in the past). Compared to field offsets, the bit drilled very smoothly and aided the operator in placing the well in the correct direction with minimum bit-torque caused from bit and formation interaction. Offset bits fail to achieve the required directional plan in the past because of the severe nature of drilling in the area.This integrated solution resulted in a 15% improvement in the ROP as compared to the offsets and a 57% improvement in footage drilled. This performance replaced six drill bits, which were used to drill the same interval in the offset wells. The new innovative PDC cutter technology saved the operator at least USD 250,000 from the planned authority for expenditure (AFE) cost, as well as set two consecutive footage records. This paper outlines the problems in drilling this challenging area, the thought process behind using the various technologies incorporated in the PDC bit design and the keys to overall success.

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“…They found that K IC increased from 0.93 MN m −3/2 at atmospheric pressure to 4.2 MN m −3/2 at a confining pressure of 62 MPa. Zijsling (1987) found that due to low permeability, cavitation will occur in the crushed zone, even with very small layer thicknesses. The result, combined with narrowing to a box cut, implies that the full width of the cut has to be covered with chisels/pick points.…”

Section: Introductionmentioning

confidence: 99%