US 3756076 A
A hydraulically controlled device to transit measurements taken at the bottom of a well to the surface, by means of pressure impulses created by periodical restrictions on the passage of the drilling fluid, consisting of means to control these restrictions, operated by electrical impulses, a hydraulic fluid circuit to operate the means restricting the passage of the drilling fluid, a turbine driven by the drilling fluid and a hydraulic fluid pump fixed on the same shaft, characterized by the fact that the said pump is placed in a hydraulic fluid circuit containing passages to discharge the fluid on either side of a double-action hydraulic jack, to which said restricting means is mechanically connected, and an accumulator is mounted in said circuit in parallel with said jack.
Description (OCR text may contain errors)
1Jted States Patent 1 -Quichaud et a1. 1 1 Sept. 4, 1973  DEVICE WITH INDEPENDENT HYDRAULIC 3,302,457 2/1967 Ma es 73/152 CONTROL TO TRANSMIT MEASUREMENTS TAKEN AT THE BOTTOM OF A WELL Primary ExammerJerry W. Myracle Att0rney1-Iolcombe, Wetherill & Brisebois  Inventors: Claude Quichaud, Pau-Billere;
Jean-Pierre Le, Peuvedic, Pau, both of France  Assignee: Societe Anonyme dite: Societe  ABSTRACT Nationale Des Petroles, DAquitaine, Courbevoie, France A hydraulically controlled device to transit measurements taken at the bottom of a well to the surface, by Filed; y 14, 1971 means of pressure impulses created by periodical re-  Appl No 162,558 strictions on the passage of the drilling fluid, consisting of means to control these restrictions, operated by electrical impulses, a hydraulic fluid circuit to operate the  Apphcatlo Pnonty Data means restricting the passage of the drilling fluid, a tur- July 16, 1970 France 7026213 bine driven by the drilling fluid and a hydraulic fluid pump fixed on the same shaft, characterized by the fact  US. Cl. 73/151 that the said pump is placed in a hydraulic fluid circuit  Int. Cl E2lb 47/12 containing passages to discharge the fluid on either side  Field of Search 73/155, 151, 152; of a double-action hydraulic jack, to which said re- 175/48 stricting means is mechanically connected, and an accumulator is mounted in said circuit in parallel with  References Cited said jack.
UNITED STATES PATENTS 2,964,116 12/1960 Peterson 175/48 5 Claims, 2 Drawing Figures 57- l 22 Z %22 GS 3 Patented Sept. 4, 1973 1 H H 3 mm M W 4 8 7 ////7/////// 7 7/ 7////2//Z%//////Z/% 7/ 7 7//////// 47/ M B 6 w 1 DEVICE WlITll-KINDEENDENT HYDRAULIC CONTRQL T TRANSMKT MEASUREMENTS TAKEN AT THE BOTTOM OF A WELL The present invention concerns a device with independent hydraulic control, used to transmit signals representing measurements taken at the bottom of a well to the surface.
During the drilling of a well, it is very useful to know numerous variables such as the resistivity of the layers being traversed, the hardness of the rock, wear or deviation in the drilling tool, the moment and weight to which it is subject, and its rotating velocity, without interrupting drilling operations. Such information can be used to examine and adjust drilling conditions. lProcesses already exist for automating drilling by the measured use of data picked up during drilling by sensing devices which convert the physical quantity measured into an electrical signal.
Transmission of such information from the bottom of the well to the surface presents difficulties. The use of electrical cables to convey the electrical signals resulting from conversion of the data picked up by the sensors or inclinometer is incompatible with rotary drilling, because of the considerable difficulty of installing a continuous cable in a sectional drilling column, and the complications it involves in the operations needed to replace worn tools.
On the other hand, the flow of drilling fluid normally discharged inside the collars carrying the tool can form a suitable fluid medium for transmission of signals, by means of pressure variations created at the bottom of the well, without disturbing ordinary drilling operations.
Up till now research has been concentrated on designing more or less complex devices intended to produce series of hydraulic impulses in the drilling fluid representing a physical measurement taken at the bottom of the well during drilling. A common feature of all these inventions is the lack of power in the well-bottom transmitting device, which generally makes it hard to distinguish the signals on the surface, against the background noise of the pumps, and which has prevented most of them from being developed commercially.
The present invention is designed to provide a solution to this drawback, by making appropriate use of the amount of power available in the hydraulic fluid. More specifically, it concerns a device with independent hydraulic control, designed to transmit to the surface signals representing measurements taken at the bottom of the well, in the form of pressure impulses created by regular restrictions on the passage of the drilling fluid, consisting of an appliance controlling the regular restrictions of the passage of the drilling fluid, operated by the electrical impulses connected with the measurement signals, a hydraulic fluid circuit being used to operate, through the said hydraulic control, a doubleaction hydraulic jack connected mechanically to means of restricting periodically the passage of the drilling fluid, a turbine driven by the drilling fluid and a hydraulic fluid pressure pump attached to the same shaft, characterized by the fact that the said pump is placed in a hydraulic fluid circuit containing passages to discharge the fluid on either side of a double-action hydraulic jack, to which is mechanically connected an appliance to restrict the passage of the drilling fluid.
The invention is more specifically characterized by the hydraulic fluid circuit including the said pump discharging fluid under pressure, by means of a control appliance such as a slide-valve or electro-valve on either side of the piston of a double-action hydraulic jack connected mechanically to an appliance to restrict the passage of the drilling fluid.
The advantages of the present invention lie in the combination of an axial turbine and a hydraulic fluid pressure-pump, and also in the particular lay-out of the hydraulic fluid circuit.
The turbine supplies a large amount of mechanical power from the drilling fluid and is compatible with the equipment generally used in drilling wells. A hydraulic oil-pressure pump is a light, compact, powerful hydraulic generator, perfectly suited to the requirements of drilling equipment, and also used in aeronautical construction, under unfavourable environmental conditions The energy transmitted by such a pump is used to control the restriction appliance, ensuring perfect reliability of functioning, and with high efficiency, in combination with a double-action jack.
The application of the double-action jack makes the operation of the restriction appliance more reliable than is the case in earlier systems, since the energy required to operate it comes entirely from the hydraulic fluid pressure pump, so that it is more or less independent of constraints occurring when the mud energy is used directly in the hydraulic fluid control circuit, notably because of pressure and compositional variations.
The lay-out of the hydraulic fluid circuit operating the double-action jack allows the fluid under pressure to be discharged, depending on the position of the control appliance such as an electro-valve, either on the upward or downward side of the jack controlling the means of restricting the passage of the drilling fluid.
According to one recommended embodiment, the pressure pump is connected, in shunt, to an accumulator of hydraulic fluid under pressure, consisting of one or more pistons housed in cylinders and receiving, on one side, the fluid discharged by the pump, and with the other side communicating with the suction inlet of the pump and simultaneously pushed back by one or more prestressed springs.
This embodiment may include a fluid-pressure limiter, consisting of a valve-needle closing an aperture connecting the pump discharge and pump intake points, subject to the discharge pressure of the pump and pushed in the opposite direction by the thrust from a spring with adjustable calibration; when pressure is too high, this limiter allows the oil to pass directly from the discharge side of the pump to the intake side.
The intake pressure of the pump may be transmitted to a mobile surface, in the form of a compensating piston, for instance, the other side of which is subjected to the pressure of the drilling fluid, so as to allow the oil to expand and to compensate the apparent variation in total volume resulting from displacement of the jack rod operating the passage-restriction appliance.
The device according to the present invention is illustrated by, without being confined to, the example of its embodiment shown in the accompanying figures.
FIG. 1 shows a special ballast-rod containing the well-bottom hydraulic installation with the turbine supplying the energy. This collar possesses end threads in conformity with API standards, and can be assembled easily at any point on the drilling line, preferably immediately next to the drilling tool.
FIG. 2 represents the hydraulic power circuits needed to operate the components such as flap-, clackor other valves or needle-valves producing restrictions on the circulation of the drilling mud.
The special collar containing the bottom hydraulic installation shown in FIG. 1 contains ends(2)which have standardized threads for assembly in the drilling line, a wide bore compatible with these threads and designed to hold the internal fittings, and a shoulder (11) to support these fittings.
The internal fittings are contained in a watertight tube (3) linking the turbine (4) with the restriction appliance or valve (5). The annular space left free between the bore in the collar (1) and watertight tube (3) allows the drilling fluid to pass from the valve (5) to the turbine (4).
The fixed blades ('7) and mobile blades (8) of turbine (4), which is of standard type, are held by the nuts 9 and 10 respectively in the casing of the turbine (4) on the shaft (6), which has a suitable shoulder.
The drilling fluid penetrates into the fixed blades through a series of apertures situated at the top of the casing (4), and comes out axially at the bottom of the turbine, providing the standard irrigation of the drilling tool.
The shaft (6) of the turbine, held by the thrust-block (13) directly drives the shaft (24) of the controlling fluid pump at the lower end of the hydraulic circuit, through a watertight passage (12), and in certain cases also drives an independent electricity supply apparatus, such as a small alternator (14).
The central part of the tube (3), shown in detail in FIG. 2, contains the well-bottom hydraulic installation, from which emerges the driving rod (57) of the needlevalve (16), acting with the seat to produce restrictions on the passage of the mud column. The invention is not confined to the use of a needle-valve acting with a seat, since hydraulic operation of the jack-rod(57) allows other methods of restriction to be used, such as dome-valves or balanced valves with multiple seats.
FIG. 2 shows one embodiment of the hydraulic power device to operate the restriction valve. This figure clearly shows how the device operates. The watertight tube (3) contains all the hydraulic components, held between an upper shoulder (65) and the upper end (61) of the turbine casing (4), which is screwed into the tube (3). From bottom to top are the hydraulic pump (25), the limiter casing (30) containing the free piston (31), the accumulator casing (41), the base (53) of the slide-valve or electro-valve shown here diagrammatically (50), the cover (54) and the jack (55). All these components are cylindrical in form, so as to fit perfectly inside the tube (3), and possess, on their plane end surfaces, communication openings equipped with sealing devices such as O-rings. This lay-out allows use to be made of single-piece cylindrical units which can withstand all drilling impacts and vibration, and which are small enough in diameter to be compatible with normal well-bottom equipment. In order to reduce vibration forces, these components are preferably made from aluminium-based light alloys, which have the advantage of being small in mass and with a good heat-transfer coefficient. The machining of housings for various parts and drilling of pipes are carried out in the mass of the components, the outside apertures of the passages used for this work being blocked subsequently with plugs (33), if the hydraulic circuit requires this.
The pump (25) is of the gear type (28), carried on bearings (27) and with a sealing device (26) on the shaft (24), but the invention is of course not confined to the use of this type of pump. It sucks in the driving fluid, for instance the oil in the reservoir (34) of the limiter casing (30), directly connected with the reservoir (47) of the accumulator casing (41) by the pipe (64). The reservoir (34) contains a free piston in the form of a compensating piston (31), the other side of which is in communication with the drilling fluid under pressure, through the opening (35). The purpose of this free piston is to allow the oil or other driving fluid to expand, and to compensate the apparent reduction in total volume resulting from the movement of the jackrod (57).
Immediately above the reservoir (34) is the adjustable pressure-limiting device. The pump (25) discharges the fluid under pressure into the passage (32) and into the seat (36), closed by the needle (37) of this limiter. When pressure reaches a pre-set level, the force on the needle (37) balances the force of the spring (38) wound up by the screw (39). The needle then tends to open, to allow part of this pressure fluid to return to the reservoir (34). An increase in the flow of the pump (25), resulting for instance from an increase in the velocity of the turbine, does not produce any increase in pressure, because of this diversion of the flow by the limiter.
The fluid under pressure discharged into the passage 32 next passes through the filter 40, which retains any impurities that could affect the functioning of the slidevalve (50).
The filtered fluid is directed into a pressure reservoir (48), through the passage 44. This reservoir is contained in the accumulator, which is constructed in the form of a cylindrical block and is in contact with one or more pistons (42) sliding inside a cylinder-block (41) and subject on one side to the discharge pressure of the pump and on the other to the intake pressure of the pump, increased by the force of one or more prestressed springs (43). The upper end of the reservoir (43) is closed by a plug (45). The accumulator unit is constructed in the same way as the limiter. In particular, the pressure fluid channels (44) and fluid return channels (46), and the cylinders and accompanying channels, are machined directly in a block of metal, which may be a light aluminium alloy.
Above the accumulator under pressure is a base (53), to which is attached the distributor component shown diagrammatically here (50), and which may be a slide-valve or electro-valve.
The controljack for the restriction appliance consists ofa cylinder (55) and piston (56) operating a rod (57). The piston (56) can move either upwards or downwards, depending on whether the fluid pressure is conveyedbelow or above the piston. The passages 51 and 52 connect the two sides of the piston with the distributor, providing this possibility.
The distributor is a component controlled by an electrical signal which can act on two separate windings. When one of these windings is excited, it provides communication between the fluid under pressure and one side of the jack piston, on the one hand, and between the fluid sucked in by the pump and the other side of the piston, on the other hand. If the other winding is excited, communications are reversed, and the piston can move in the other direction. if neither winding is excited, there is no communication, and the piston cannot move.
The discharge from the pump (25), driven continuously by the turbine, driven in turn by the drilling fluid, keeps the reservoir (48) filled with driving fluid under pressure, which, in the event of exceeding of the pressure threshhold, circulates through a diversion, by means of the pressure limiter (37), the adjustable calibrated spring of which allows the threshhold to be regulated.
Data, concerning the rock hardness, for instance, are collected with sensing devices, not shown here, situated near the drilling tool, and converted into electrical signals representing the measured quantities.
These signals are processed or coded in electronic circuits contained in watertight enclosures (22), and supplied with electrical energy by low-powered independent means such as a small alternator (14), also driven by'the turbine (4). This processing or coding produces low-powered electrical impulses which can operate the hydraulic fluid control appliance. To create a hydraulic impulse in the form of a momentary increase in the pressure of the drilling fluid, the circuits contained in the enclosures (22) deliver a brief electrical impulse applied to the distributor winding (50), controlling displacement of the jack to the position which causes a sharp restriction, followed after a moment by a second electrical impulse, also brief in duration, which is applied to the other distributor winding and causes the jack to return to the position where it causes no restriction. These electrical impulses, coded or uncoded, are transmitted along wires (58), which traverse the cylinder block (55) to the hydraulicfluid controlling appliance, such as the windings of the distributor (50). This opens up access in turn for the fluid to each side of the piston (56) of the jack (55). The movement of the piston causes the needle (16), fixed to the piston, to close and open in turn. Because of the effect of the spring (43), which stores up the energy supplied by the pump (25), the piston (56) is operated forcefully and rapidly in both directions, causing a sharp, momentary restriction on'the flow of drilling fluid circulating inside the drilling line, in the form of a pressure impulse, which is transmitted to the surface, where it is detected.
What is claimed is:
ll. A device for transmitting to the surface signals representing measurements supplied as electrical impulses by a measuring instrument located within a well, said signals consisting of pulses in the pressure of a drilling fluid in said well, which pulses are created by temporary restrictions in the flow of said fluid, said device comprising:
means for restricting the flow of said fluid,
a double-acting hydraulic jack connected to operate said restricting means,
a turbine driven by said drilling fluid,
a fluid pressure pump driven by said turbine,
a hydraulic fluid circuit supplied by said pump and connected to apply the pressure produced by said pump to either side of said jack,
means in said fluid circuit responsive to said electrical impulses for controlling the side of said jack to which pressure is applied, and
a pressure accumulator comprising a spring-biassed piston connected in said hydraulic circuit in parallel with both said jack and pump.
2. A device according to claim 1, comprising a fluid pressure limiter consisting of a needle-valve closing an aperture which connects the pump discharge and intake, said needle valve being subject to pressure loading in one direction by the discharge pressure of the pump and biassed in the opposite direction by spring means.
3. A device according to claim 2 comprising means for adjusting the pressure exerted on said needle valve by said spring means.
4. A device according to claim 1, in which the intake pressure of the hydraulic fluid pump is transmitted to one side of a movable piston, the other side of which is subject to the pressure of the drilling fluid.
5. A device according to claim 1, in which the means restricting the flow of thefluid is a needle-valve attached to the piston of said jack and cooperating with a suitable seat in the flow path of said fluid.