US2655038A

US2655038A - Well formation packer assembly for measuring gas-oil ratios

Info

Publication number: US2655038A
Application number: US97110A
Authority: US
Inventors: Gerald D Barton
Original assignee: Stanolind Oil and Gas Co
Current assignee: Stanolind Oil and Gas Co
Priority date: 1949-06-04
Filing date: 1949-06-04
Publication date: 1953-10-13
Anticipated expiration: 1970-10-13

Description

Oct. 13, 1953 s D. BARTON 2,555,033

WELL FORMATION PACKER ASSEMBLY FOR MEASURING GAS-OIL RATIOS Filed June 4, 1949 INVENTOR. GERALD D. BARTON m'm y llw ATTORNEY Patented Oct. 13, 1953 WELL FORMATION PACKER ASSEMBLY FOR MEASURING GAS-OIL RATIOS Gerald D. Barton, Tulsa, Okla., assignor to Stanclind Oil and Gas Company, Tulsa, Okla., a corporation of Delaware Application June 4, 1949, Serial No. 97,110

(Cl. 'i3155) Claims. 1

The present invention relates to a novel .type of well formation packer assembly. More particularly, it pertains to a novel packer assembly having by-pass and valving means suitable for use in wells such as, for example, oil wells in which the ratio of gas to liquids produced is quite high.

An object of my invention is to provide a packer capable of readily maintaining its original position of setting when employed in wells having a high gas to oil ratio. It is a further object of my invention to provide a packer suitable for use in wells having a high gas to oil ratio wherein the volume of gas escaping from the packed oil zone of the producing formation across the packer can be measured as it passes through the latter. A still further object of my invention is to provide a packer capable of separating in a satisfactory manner oil from gas, both of which are being produced from the same restricted zone,

by allowing the gas to escape from said zone through a conduit communicating with the zone above and the packed ofi zone immediately below the packer, the passageway being capable of opening and closing at a predetermined level of the liquid in the packed off zone.

Packing elements of the type contemplated by my invention are useful in carrying out various operations in the presence or high gas pressures in a well bore. For example, in identifying fluids and their respective rates of production in a restricted zone, such as are described and claimed in copending application U. S. S. N. 97,764, filed June 8, 1949, by Ralph E. Hartline and Joseph D. Eisler, the device or the present invention may be advantageously employed. According to the aforesaid copending application well fluids may be identified and the respective rates at which these fluids flow may be determined by placing a string of vertically spaced electrodes in a packedoff zone in the well bore. The rate oi flow of oil or water is measured by following the movement of the oil-water interface in the zone defined by two packers. The total fluids produced in the particular zone investigated is computed by the aid of a flow meter located in the tubing connecting the packers and which measures only the product from said zone. Production, preferably at a constant rate, is commenced and the rate of rise or fall of the oil-salt water interface is determined by observing the time at which the interface passes the electrodes. It the well fluid in the test zone is principally salt water at the time of setting the packers, the oil-water interface is high in the zone, initially. The lnteriace then moves downward during the test period if oil production occurs, and its rate of fall establishes the oil production rate if the bore hole diameter is known. By determining the total production passing through the flow meter and subtracting the production rate of the oil, as determined above, the production rate of the salt water can be ascertained. Thus, in systems for identifying and determining production rates of well liquids by gravimetric collection between packers in a restricted zone of an oil well, there is placed a differential pressure across the top packer equal to the static head resulting from the difference in density between the original fluid in the packed off zone and the fluid being produced plus the differential pressure resulting from the flow of the produced fluid. When the fluid collected under the upper packer is crude oil, the resulting differential pressure is not excessive and the requirement that the packer confine the produced fluid against this differential pressure does not impose too great a limitation upon its operation. The requirements imposed upon the upper packer are, however, much more severe when gaseous products produced from the packed of! area accumulate under the packer. The greater density dliierence results in a markedly higher packer load imposed by the differential pressure thus produced. The term "density" as used herein reiers to the differential pressure exerted on the underneath side oi packer 2 produced by the hydrostatic head of the column of oil standing in tubing 4 on the column of oil and gas in the packed of! zone with which the oil in tubing 4 is in communication through a conventional entrance port. Owing to the presence of gas in the column of fluid confined by the packed oil zone, the density of that column is less than the column 01' oil standing in the tubing. It is this diiierence in density of these respective columns that produces the above-mentioned diiierential pressure. The identification oi the well fluids and the determination or their respective production rates also becomes more complex by the creation 0! the gas-oil and oil-water interfaces. The gas-oil interface cannot be identified by means of the usual conductivity measurement systems. Moreover. it is the relatively more valuable liquid volume whose production rate is generally desired to be ascertained. With apparatus previously employed for measuring the production rates of well fluids in a packed 0!! zone, much dlfllculty has been encountered where high gas to oil ratios prevail. Under such conditions the gas pressure tends to build up until the upper packer becomes dislodged from its original setting thereby allowing a mixture 01 gas and entrained oil to pass upwardly around the packer into the unrestricted zone the well bore. Obviously, under circumstances such as these, it is impossible to measure accurately the oil production rate irom the test zone.

In order to reduce the packer load to a minimum in wells having a high gas to oil ratio and to allow measurement 0! the more valuable oil; I: have devised a packing unit assembly suitable ior hy-passing produced gas across the. packer. Thus, my invention contemplates the utilization oi a conduit in communication with. the zonev above the packer and the test zone-immediately below the packer, said conduit being capable of opening and closing at a predeterminedlevel otthe liquid in the test zone. The opening and closing oi the conduit may be effected by any oiseveral known methods such as by the utilization of a-llquid level responsive means, ior'example, a hoot actuated valve. Such valve remains in a closed position as the result at the buoyant force exerted on the float by the oil. The corresponding force exerted by the gas, however, is insufficient to maintain thevalve closed andithe gaseous products are accordingly vented through the packer into the unrestricted zone above the unit until the gasoil interface rises to lift the float and close the valve. By employing a float valve, 3

for example, of the snap action" type. in which a definite diflerential motion of the float is required between iull open and completely closed positions, it is possible to obtain. an approximate quantitative measurement oi the vented gaseous products. A switch attached to the valve can then transmit a signal through the switch circuit to a suitable recording means whereby estimation can be made or the volume of produced gas.

A preferred embodiment of the packing unit of my invention may be described with more particularity by reference to the accompanying drawing in which a packer 2 isdisposed about a well tubing 4 having mounted therein a passageway or conduit 6. A :loat actuated valve assembly is shown attached to the lower portion of conduit. 6 provided with seat 8; The buoyant force of the-liquid oil applied to float, lfl-attached to arm 12, which is hin-gedly mountedrto welltubing I at-ll, functions to close conduits by'means of valve stem IS. The correspondingiiorce exerted'bythe-gas insufliclent to maintainvalve seat 8 in the "closed" position, and, as a result. gaseous products from the tomatlonare vented into the well bore above packer t'through: port [8 of conduit 8. Gaseous products continue to-be vented into the well bore until thegas-oilintel-face rises to lift float i0- bringingvaive seat 8 and'vaive stem it again into sealing'relationship. By knowing the volume of gas required'to lower the liquid-gas interface so that the float valve stem IG- disengages seat 8, and by knowing the volume of gas remaining atter'said gaoandiliqulzi interface causes the now valve stem is to disengage seat 8. the gas production rate can be calculated. Thus, the number oi times matsthe sys- 'tem opens and closes per minute can readily be observed on recording ammeter ld which' indicates completion and breaking oi circuit 22 through electrical contacts Hand 28. The lengt of time the circuit remains open and ciosedimay be recorded on a suitable time-driven recording roll 28 by needle 30 actuatedby recording ommeter 20. Uniform movementoiroll-It is accom- 4 pllshed by known means, such as clock mechanism 32.

When employing a packing element oi the type contemplated by my invention in isolating an intermediate well bore zone, it is desirable to provide exhaust ports in the well tubing above and below the packed oflf zone-iniorder that gas or oil produced in the unrestricted zones of the well bore can be withdrawn therefrom into the pro- 1 duction string and thereby avoid undue stress on the packing units.

It is apparent that various modifications can be made in the above-described apparatus without departing irom. the scope of my invention. In general, it may be said that the apparatus hereinset forth is applicable to the solution 02 problems created by the presence of excessive volumes 01 gas in a web bore wherein it is de sired either to qualitatively separate gases from liquids or to measure the production rate of such ases.

What I-claimis:

1. In a wellpacker. assembly for handling gas in a packed ofi zone of swell bore producing oil and gas, the combination cOmprisingJa well tubing, a packing element disposed about said tubmg, there being an open-ended conduit communicatin with the zone above. and with. said packed off zone-immediately below said packing element, and a liquid level responsive vaivemeans attached to said tubing anmadaptedto close the end of said conduit communicating: with: said zone immediately below said packing element at a predetermined liquid level in said. packed on zone.

2. In a well packer assembly for handling. gas in a packed oiI zone 01 a well bore producing oil and gas, the combination comprising awell tub ing, a packing element disposed aboutsaid tubing, there being an open-ended conduit in. said tubing communicating with the-zone above and with said packed of! zone immediately below said packing. element, and a float actuated valve means. attached to said tubing and adapted to close the end. or said conduit. communicating with said zone immediately below. said packing element at a. predetermined liquid level in said packed oi! zone.

8. A. packer. assembly for handling: gas im a packedofl zone. of. a well bore producing oilsand gascomprising a well tubing, 9. packingelement disposed. about sairhtubing. there bein -an openended conduit. in saidtubing. communicating with the zone; above and. with saidpackedi of! zoneimmediately below said packing element, means including liquid. level. responsive valve means attached' to: saidtubing and adapted to openand close the. end-oi said conduit communicating with thezone irnmediatebr-beiowsaid pack-- m8. element at a predetermined liquid level. in midpacked 0.11 none.

4;. Inc packer assembly tor-handling gas in a packedaoii zone'ot. a wellzbore producing oil and gas. the combinationicomprising a weiltubing; a

packing element disposed-about said tubing. there beingan open-endedioonduit insaidtubingcommunicating with the zone above and with said packedoil zonczlmmediately below saidpacking element, a. liquid level responsive valve means atbachedto said tubing and adaptedto close-the end oisaid conduit communicating with; the zone immediately bdow said packing. element at a predetemiinedlliquid leveizinasaid packedioit zone, a circuit including a switch connectedto and ao- 5 tuated by said valve means which closes said circult simultaneously with the closing 01 said liquid level responsive valve means, and means for producing an indication of electrical current flow in said circuit.

5. In a packer assembly for handling gas in a packed 01! zone of a well bore producing oil and gas, the combination comprising a well tubing, a packing element disposed about said tubing, there being an open-ended conduit in said tubing communicating with the zone above and with said packed oi! zone immediately below said packing element, a float actuated valve means attached to said tubing and adapted to close at a predetermined liquid level in the packed ofl zone of a well bore the end of said conduit communicating with the zone immediately below said packing element, a circuit including a switch connected to and actuated by said valve means which closes said circuit simultaneously with the closing 0! said valve means, and means for producing an indication of electrical current flow in said circult.

GERALD D. BARTON.

Reterences Cited in the file of this patent UNITED STATES PATENTS