Natural gas production from geopressured aquifers

Claim 3

The method of claim 1 further comprising the steps, prior to permitting the initial flow of geopressured gas-saturated water, of: (1) permitting the free flow of gas-saturated water into the well; (2) using fluid flow control means located within the well bore to prevent the flow of fluid; (3) equalizing the pressure in the well bore above and below the fluid control means; (4) operating the fluid control means to permit fluid flow; and then (5) beginning and gradually increasing the flow of gas-saturated water, until the full flow capacity of the well under atmospheric pressure is achieved.

Claim 4

The method of claim 2, wherein step (2) further comprises: (a) inserting fluid flow control means within the well-bore at a point between the top of the aquifer and the well-head; (b) completing and closing the well-head; and (c) engaging the fluid flow control means to prevent the flow of fluid.

Claim 5

The method of claim 3 further comprising the steps, subsequent to permitting the initial flow of geopressured gas-saturated water, of: (6) pumping out the water at the well-head at a gradually increasing rate, so as to cause the substantial absence of back-pressure; and (7) maintaining the substantial absence of backpressure after gaseous flow commences.

Claim 6

The method of claim 4, wherein the free flow of gas-saturated water into the well is facilitated by fitting a sand screen to that portion of the well-bore penetrating into the aquifer.

Claim 7

The method of claim 6, wherein the fluid flow control means is an inflatable retrievable bridge plug which is placed at a point not more than about 100 feet above the top of the aquifer and inflated sufficiently to withstand a pressure greater than the geopressure of the aquifer; and which is operated to permit fluid flow by removal from the well bore by deflation, retrieval by means of a cable connected between the bridge plug and the well head, and storage within the well head.

Claim 8

The method of claim 6, wherein the gas is permitted to flow until the water surrounding a gas cap formed under an initial well is at least partially gas-depleted, whereupon additional wells of the same nature are drilled approximately equidistant from the initial well and approximately equidistant from each other, said additional wells being located approximately along an imaginary circle approximately concentric with the first well and constituting a first ring, with the proviso that the wells of the first ring are sufficiently close to each other and to the first well, so that the gas cap formed by each well intercepts the gas cap formed by each adjacent well, thus forming a single gas cap.

Claim 9

The method of claim 7, wherein after production from the wells of the first ring has exsolved sufficient natural gas from the aquifer water surrounding the gas cap so as to cause a reduction of gas production from the first ring and a substantial cessation of gas production from the initial well, the initial well is capped to form an inner volume of substantially gas-depleted water within the gas cap whose gas/gas-depleted-water interface forms an inner edge of the gas cap, and additional wells of the same nature are drilled approximately equidistant from the first ring and approximately equidistant from each other, said additional wells being located approximately along an imaginary circle approximately concentric with the first ring and constituting a second ring, with the proviso that the wells of the second ring are sufficiently close to each other and to the wells of the first ring, so that the gas cap formed by each well intercepts the gas cap formed by each adjacent well and the existing gas cap.

Claim 10

The method of claim 8, wherein a plurality of additional concentric rings of increasing diameter of gas wells of the same nature and spaced apart in the same manner are drilled, with the proviso that not more than five adjacent concentric rings of gas wells are simultaneously in production, and with successive capping of the wells of inner rings, so as to form a single gas cap having a continuously expanding outer edge and an associatively continuously expanding inner edge.

Claim 11

The method of claim 13, wherein not more than three adjacent concentric rings are simultaneously in production.

Claim 12

The method of claim 14, wherein the concentric rings are broken by the outer boundaries of the aquifer, so that no wells are drilled outside of the aquifer.

Claim 13

The method of claim 11, wherein the concentric rings are broken by faults in the aquifer, so that no wells are drilled on the other side of the faults from the initial well.

Claim 14

The method of claim 2 further comprising the steps, subsequent to permitting the initial flow of geopressured gas-saturated water, of: (6) pumping out the water at the well-head at a gradually increasing rate, so as to cause the substantial absence of back-pressure; and (7) maintaining the substantial absence of back-pressure after gaseous flow commences.

Claim 22

The method of claim 19, wherein after production from the wells of the first ring has exsolved sufficient natural gas from the aquifer water surrounding the gas cap so as to cause a reduction of gas production from the first ring and a substantial cessation of gas production from the initial well, the initial well is capped to form an inner volume of substantially gas-depleted water within the gas cap whose gas/gas-depleted-water interface forms an inner edge of the gas cap, and additional wells of the same nature are drilled approximately equidistant from the first ring and approximately equidistant from each other, said additional wells being located approximately along an imaginary circle approximately concentric with the first ring and constituting a second ring, with the proviso that the wells of the second ring are sufficiently close to each other and to the wells of the first ring, so that the gas cap formed by each well intercepts the gas cap formed by each adjacent well and the existing gas cap.

Claim 23

The method of claim 20, wherein a plurality of additional concentric rings of increasing diameter of gas wells of the same nature and spaced apart in the same manner are drilled, with the proviso that not more than five adjacent concentric rings of gas wells are simultaneously in production, and with successive capping of the wells of inner rings, so as to form a single gas cap having a continuously expanding outer edge and an associatively continuously expanding inner edge.

Claim 24

The method of claim 21, wherein not more than three adjacent concentric rings are simultaneously in production.

Claim 25

The method of claim 22, wherein the concentric rings are broken by the outer boundaries of the aquifer, so that no wells are drilled outside of the aquifer.

Claim 27

The method of claim 23, wherein the concentric rings are broken by faults in the aquifer, so that no wells are drilled on the other side of the faults from the initial well.

Claim 31

The apparatus of claim 27, wherein the fluid flow control means further comprises: (g) fluid flow control means inserted within the well-bore at a point between the top of the aquifer and the well-head; (h) means for completing and closing the well-head; and (i) means for engaging the fluid flow control means to prevent the flow of fluid.

Claim 32

The apparatus of claim 27 further comprising (g) means for pumping out the water at the well-head at a gradually increasing rate, so as to cause the substantial absence of back-pressure subsequent to permitting the initial flow of geopressured gas-saturated water; and (h) means for maintaining the substantial absence of back-pressure after gaseous flow commences.

Claim 33

The apparatus of claim 27 further comprising a sand screen fitted to that portion of the well-bore penetrating into the aquifer.

Claim 34

The apparatus of claim 27 wherein the fluid flow control means is an inflatable retrievable bridge plug placed at a point not more than about 100 feet above the top of the aquifer and being inflatable sufficiently to withstand a pressure greater than the geopressure of the aquifer, said bridge plug being deflatable to permit removal from the well-bore to permit fluid flow, said bridge plug being connected to the well-head with a cable to permit retrieval and storage.

Claim 37

The system of claim 32, including means for capping the initial well to form an inner volume of substantially gas-depleted water within the gas cap whose gas/gasdepleted-water interface forms an inner edge of the gas cap, and additional wells of the same nature drilled approximately equidistant from the first ring and approximately equidistant from each other, said additional wells being located approximately along an imaginary circle approximately concentric with the first ring and constituting a second ring, with the proviso that the wells of the second ring are sufficiently close to each other and to the wells of the first ring so that the gas cap formed by each well intercepts the gas cap formed by each adjacent well and the existing gas cap.

Claim 38

The system of claim 33, including a plurality of additional concentric rings of increasing diameter of gas wells of the same nature drilled and spaced apart in the same manner with the proviso that not more than five adjacent concentric rings of gas wells are simultaneously in production, and including means for the successive capping of the wells of inner rings, thereby forming a single gas cap having a continuously expanding outer edge and an associatively continuously expanding inner edge.

Claim 39

The system of claim 34, wherein the concentric rings are broken by the outer boundaries of the aquifer with no wells drilled outside of the aquifer.

Claim 40

The system of claim 35, wherein the concentric rings are broken by faults in the aquifer with no wells drilled on the other side of the faults from the initial well.