Dec. 1967 J. RAYNAL ETAL
3 ABRASIVE RESISTANT ELEMENTS FOR THE
VENTS OF ROTATABLE DRILLING TOOLS AND METHOD OF MANUFACTURE Filed May 18, 1965
2 Sheets-Sheet 1 0 0.1000000 op o\ 8b l3 49b 15a 4a ATTORNEYS Dec. 19, 1967
RAYNAL ETAL 3,358,783
THE VENT ABRASIVE ISTAN
LEMENTS FOR F ROTATABLE DR ING TOOLS AND METHOD OF MANU TURE Filed May 18, 1965
2 Sheets-Sheet 2 INVENTORS JEAN R4 YNAL SERGE A. GSTALDEB BRUNO Pamela av O 6m
,1! W ATTOgNEYS United States Patent Ofiice 3,358,783 Patented Dec. 19, 1967
3,358,783 ABRASIVE RESISTANT ELEMENTS FOR THE VENTS OF ROTATABLE DRILLING TOOLS
AND METHOD OF MANUFACTURE Jean Raynal, Serge A. Gstalder, and Bruno Renard,
Pau, France, assignors to Societe National des Petroles dAquitaine, Paris,
France Filed May 18, 1965, Ser. No. 456,772 Claims priority, application
France, June 4, 1964, 976,992; Mar. 2, 1965, 7,649 11 Claims. (Cl. 175-393)
ABSTRACT OF THE DISCLOSURE A rotatable drilling tool having fluid blades of the
full body or ring type with a central input conduit for thepassage of drilling
fluid under pressure, a head having areas provided with cutting elements and
areas without cutting elements alternating with said cutting areas, vents for
distributing the drilling fluid opening on to the areas and each being
connected to the central conduit; the vents being constituted by elements whose
resistance to abrasion is greater than that of the matrix of the tool.
The present invention
relates to improvements in rotatable drilling tools having
fluid blades, as well as a method of manufacturing a drilling tool of this
type.
The invention relates
more particularly to rotatable drilling tools having fluid blades of the full
body or ring type, comprising a central input conduit or channel for the
passage of a drilling fluid under pressure, a head having areas provided with
cutting elements, such as diamonds, cutting edges made of tungsten carbide, or
even individual cutting blades, and areas without cutting elements, these areas
alternating, and the areas without cutting elements being generally located in
a rearward position with respect to the areas having the cutting elements,
vents for distributing the drilling fluid arranged in the head perpendicularly
to said areas, and opening out on to said area provided with cutting elements
and/or on the areas without cutting elements, and eachconnected to the central
conduit or channel of the tool.
It is known that the
efliciency of such a tool, ie its speed of advance, which is a function of the
rotation speed of the tool and of its bearing pressure on the ground, in
addition depends on the efficiency of the jet of the drilling fluid which
itself depends upon the speed of the drilling fluid at the output of the vent,
upon the distance between the lower extremity of the vent and the cutting face,
and upon the abrasive properties and the density of the
drilling fluid.
In drilling tools of the
above mentioned type, the vents do not stand up to the abrasive elfects of the
drilling fluid for a suflicient time, so that it is not possible to maintain
the jet of fluid at a speed corresponding to its maximum efliciency. Moreover,
when the vents are situated in the areas having no cutting elements, which
areas are generally rearward of the cutting areas so as to allow the drilling
fluid to evacuate the swarf and cuttings, the distance between the lower
extremity of the vents and the cutting face is sufliciently large so that the
efficiency of the jet is further diminished.
The present invention
obviates or minimizes all the above mentioned disadvantages and has for a
particular object the production of a drilling tool of the above mentioned
type, the vents of which have a resistance which is suflicient to allow the use
of a speed for the vents, maximum density and abrasiveuess of the drilling fluid,
compatible with the drilling