Wells – Processes – With indicating – testing – measuring or locating
Reexamination Certificate
1998-08-07
2002-10-15
Neuder, William (Department: 3672)
Wells
Processes
With indicating, testing, measuring or locating
C166S066000, C166S066600
Reexamination Certificate
active
06464004
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed generally to well data monitoring and control systems for acquiring downhole well data such as pressure, temperature, fluid flow rate, etc. of the fluid that is located within a well and for controlling various downhole well operations, particularly operations concerned with production of fluid from the well and displaying such data or otherwise controlling the well in response to such data. More particularly, this invention concerns the provision of a mandrel(s) or tubing carried well tool holder run into a well on a tubing string and which is provided with a plurality of internal, bottom entry, instrument or tool side pockets which are electrically inter-connected for power/control purposes to thus enable electronic well data sensors, instrument electric power equipment, well controller instruments and the like to be installed and retrieved, such as by use of a wireline running tool run inside the tubing while the tubing string and mandrel remain undisturbed within the well. This invention also concerns bottom entry, multiple pocket, tubing installed, mandrel(s) that can be adapted for housing instruments for controlling gas-lift valves or the like and other artificial lift devises such as submersible pumps and which instrument can also be installed and retrieved by wireline operations.
Each of the possibly multiple side pockets of such mandrel(s) are equipped with electrical connection means enabling circuit completion upon installation of an instrument or other electronic interconnection of apparatus located within the various pockets of the mandrel(s). The present invention is also directed generally to electrically operable gas-lift valves which can be operated from surface located controls via an electric wireline extending from the surface to the downhole gas-lift valve mandrel(s) or which alternatively can be operated by a programmed on-board electronic controller and power system. The present invention is further directed to the acquisition of well data such as pressure, temperature, fluid flow, etc. and also such monitoring and acquisition equipment incorporating a remotely operable valve for changing valve positioning for gas-lift operations and a downhole controller processor that can be programmed or reprogrammed according to the production capability of the well.
Description of the Prior Art
When wells are drilled and completed for the production of petroleum products the hydrocarbon bearing subsurface formations being encountered, unless the formation has been produced by other wells, typically has sufficient formation pressure via natural gas pressure in the formation fluid to produce fluid from the well by forcing it from the subsurface zone to the well bore and thence upwardly from the formation depth to the surface through a production tubing string that is suspended within the well casing. After the well has been produced for a period of time, determined by the character, volume and other parameters of the subsurface oil bearing formation, the natural gas pressure or drive will diminish to the point that efficient hydrocarbon production will cease. To continue well production, other artificial lift production systems, such as pumps, gas-lift systems, waterflood systems and the like can be employed. When the decision is made to change the well completion for different well fluid production parameters, it is typically necessary to bring a work-over rig to the well site, pull the production tubing string from the well and replace it with a production tubing string of the character desired, i.e. pump, gas-lift, etc. Considerable well down time, work-over costs end equipment costs are routinely required for well work-over of this nature. It is desirable therefore to minimize the expense of a work-over rig and its personnel for converting wells from formation pressure induced oil production to production by gas-lift or other artificial lifting means.
It is known in the gas-lift oil production art to provide a production tubing string having a plurality of spaced gas-lift mandrels with a gas lift valve pocket in each of the mandrels. To temporarily isolate the interior of the valve pockets from casing annulus pressure and from the fluid that may be present therein, dummy valve elements may be inserted into the valve pockets to seal and protect the interior polished seal sections of the pocket and thereby to isolate the production tubing from the casing annulus pressure that is present at the gas inlet port of the valve pocket. One of the problems with the use of such dummy valves is that retrieval of a dummy valve by a retrieval tool leaves the valve pocket open and in unchecked fluid communication with the production tubing until such later time as a gas-lift valve is subsequently run through the tubing string and installed within the pocket. This unchecked fluid communication can result in sufficient gas pressure change or pressure drop to stop flow or kill the well so that other expensive and time consuming operations are required to restore the well to active production. It is desirable therefore to provide a well control system that can produce a well efficiently by means of natural formation pressure and which can be efficiently controlled in the downhole environment to produce the well by gas-lift or other artificial lift operations without risking potential killing of the well or damaging its productive capacity during the conversion process.
When a well is in reservoir pressure production or gas-lift production it is often desirable to acquire downhole well fluid parameter measurements on a reasonably continuous basis so that the well and others wells producing the formation can be produced in a manner that enhances the long term production of the formation. By monitoring production tubing pressure and/or casing annulus pressure at various well depths and by providing for a wide range of fluid flow or fluid production control, the production system for the well can be efficiently tuned for the precise flow parameters that achieve maximum long term production from the well and the field. For this reason and others, various types of downhole data sensors and recorders have been developed which are positionable within the sensor pocket of a downhole mandrel and are powered by a surface-to-sensor circuit as shown by U.S. Pat. No. 4,624,309 of Schnatzmeyer. Such sensors may also be monitored by an on-board, self contained programmable data recorder as shown in U.S. Pat. No. 5,130,705 of Allen et al. A retrievable electronic well data recorder is also shown by U.S. Pat. No. 5,327,971 of Garbutt et al.
Mechanically or electrically operated gas-lift valves that are variable in the downhole environment have generally not been available. For the most part, prior art gas-lift valves have only two positions, open or closed, whether they are mechanically or electrically operated. Adjustment of lift gas injection by electrically operated on/off valves has been achieved by controlling electrically operated valves from the surface, such adjustment being accomplished by adjusting the time sequence of valve operation. In the case of pressure responsive mechanical gas-lift valves, the rate of gas injection flow into the production tubing from the casing/tubing annulus of the valves is typically governed by the orifice dimension of each valve. To change the rate of gas flow it is typically necessary to retrieve the valve and adjust its flow rate by manually changing the orifice size. If the valve is of the pressure operated or responsive type, it is also necessary to change the charging pressure of the internal pressure chamber. It is desirable therefore, to provide an electrically operated gas-lift valve having a wide range of adjustable gas injection flow capability by orifice opening control and also having adjustable valve timing, both being adjustable in the downhole environment by programmable processor or from the surface via a surface control unit via wireline.
Electrically operated gas-lift valves have also been de
Crawford Mark S.
Jermigan Kerry D.
Sizer Phillip S.
Moser, Patterson & Sheridan L.L.P.
Neuder William
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