Patent Publication Number: US-6209642-B1

Title: Apparatus and method for enhancing fluid and gas recovery in a well

Description:
This is a continuation-in-part of U.S. patent application Ser. No. 09/057,039 filed Apr. 8, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to enhanced recovery from a well. More specifically, this invention relates to an improved apparatus that enhances recovery in oil and gas wells by employing regulated flow devices and techniques and optionally in combination the addition of fluid enhancing additives. 
     2. Related Art 
     As was discussed in applicant&#39;s application U.S. Ser. No. 09/057,039, each well has its own predetermined optimal recovery conditions which are determined by the natural geological formation of the well. When a successful well is drilled, there is commonly enough gas-volume to fluid-ratio and bottom hole pressure to create a natural flow from the well. This ability to flow at a certain velocity to insure fluids are lifted is termed “critical flow rate.” The ability to substantially maintain or simulate natural flow conditions is critical in optimizing recovery. 
     Under the natural flow pressure, fluid flow is created by virtue of the liquid being broken up into small units by gas existing therein and is carried to the surface due to a fluid “lightening” effect under gaseous expansion to achieve critical flow rate. The combined gas and liquid are transferred via an upstream flow line to a fluid/gas separator which is designed to remove the liquid into storage tanks and remove the gas to a downstream sales flow line which commonly connects with a utility service provider at what is more commonly referred to as the pipeline. 
     Unfortunately, in new tight gas sand wells or older wells having reduced reserve volumes, and pressure in the well depletes during the flow cycle and negatively impacts the optimal recovery conditions and flow needed to achieve critical flow rates. As a result, typically only part of the oil and gas contained in the underground formation by a primary recovery method which uses the natural flow force present in the reservoir is possible. A variety of enhanced recovery techniques such as artificial lift systems, so-called secondary or tertiary recovery methods, have been employed to increase the recovery of oil and gas from subterranean reservoirs. 
     A common artificial lift, secondary recovery method includes a combination of shutting in the well for a period of time to allow for pressure build up and allowing a plunger to drop to the bottom of the well and then opening the well causing the plunger to drive the fluid to the surface. Another such enhanced recovery technique is to use a pump truck to pump additives into the oil well-bore. These additives can, for example, reduce scale, paraffine and the viscosity of the oil and increase production of oil recovery. 
     A problem with these prior techniques is the lack of proper control in order to carry out those techniques during initiation and slow down of flow within a well. Also, waste can occur downstream in that metering devices of service providers to which the downstream sales flow line connects do not properly meter or record spikes (temporary large amounts of gas over that recordable by the meter) which occur during the other recovery methods. In this regard, care must be taken to maintain optimal recovery conditions in carrying out other recovery methods. 
     Applicant&#39;s prior said application is directed at solving a significant part of the aforementioned problems by providing an apparatus which controls the flow within the downstream sales line. There remains a need to improve upon enhancing oil and gas recovery techniques such as those of the present invention. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object to control well production via a remote control device. 
     It is an object of the present invention to enhance fluid and gas flow in a well. 
     It is another object to improve the apparatus for enhancing fluid and gas flow in a well. 
     It is still another object to artificially induce optimal recovery conditions in a well, while maintaining its flow at a measurable rate. 
     Yet another object is to establish flow patterns which improve the promotion of fluid break up into droplets and thus prevent fluid from falling back into the well during well shut-in periods. 
     It is another object to create another marketing vehicle for production. 
     Accordingly, the present invention is directed to an apparatus for enhancing fluid and gas flow in a recovery includes an upstream flow line communicably connected at one end to the well in a manner to receive fluid and gas therefrom. A fluid and gas separator communicably connects to another end of the upstream flow line in a manner to receive fluid and gas flow therefrom. A downstream sales flow line communicably connects to the fluid and gas separator in a manner to receive gas flow therefrom. A control valve is operably disposed in the upstream flow line. 
     A local controller device operably controllably connects to the control valve in a manner to permit regulated flow through the upstream flow line at a predetermined amount and has a communications device associated therewith. A remote controller device having a communications device therewith is also provided, wherein the local controller device and remote controller device communicate with one another to enable remote control of the control valve. 
     A pressure differential control is operably disposed in the downstream sales line for comparatively sensing pressure differential in the downstream sales line about a restricted region in the downstream sales flow line which is operably controllably connected to the control valve in a manner to permit regulated flow through the upstream flow line at a predetermined amount in response to the sensed pressure differential. 
     Another aspect of the invention includes the introduction of additives into the well-bore to increase recovery, wherein the additives are activated and controlled by flow patterns established therein. A benefit realized is the ability to size the injection tubing whereby it reduces the capacity in the flowing through the tubing such that a siphoning action is created. 
     A method of the present invention includes the steps of controllably delivering fluid and gas from a well in a single inlet flow path to a separator, separating the fluid from the gas into two separate outlet flow paths from the separator, and remotely controllably regulating flow of the fluid and the gas in the inlet path. The method also includes comparatively sensing pressure of gas about a restricted region of the outflow path, and controllably regulating flow rate of the fluid and the gas in the inlet path in response to the sensed pressures and in accordance with a predetermined flow rate. Additionally, the method may include the adding of a flow enhancing additive to the well. 
     Other objects and advantages will be readily apparent to those skilled in the art upon viewing the drawings and reading the detailed description hereafter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic diagram of the present invention. 
     FIG. 1 a  is a schematic diagram of another embodiment of the present invention. 
     FIG. 1 b  is a schematic diagram of a remote controller device of the present invention. 
     FIG. 2 is a graphical representation of the flow patterns of a well for a given period under a learning phase employing the present invention. 
     FIG. 3 is a graphical representation of the flow patterns of a well for a given period. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, the apparatus for enhancing fluid and gas recovery in a well W of the present invention is generally referred to by the numeral  10 . The apparatus  10  includes an upstream flow line  12  communicably connected at one end  14  to the well W in a manner to receive fluid F and gas G therefrom. A fluid and gas separator  16  communicably connects to another end  18  of the upstream flow line  12  in a manner to receive fluid F and gas G flow therefrom. A downstream sales flow line  20  communicably connects to the fluid and gas separator  16  in a manner to receive gas G flow therefrom. 
     A gas metering device  22  of a provider is operably disposed in the downstream sales flow line  20 . A local well site based controller device  100  is operably disposed adjacent the well W and includes a communications device  102 . The controller device  100  preferably is a CPU having a processor  101  with an associated memory  103 , display  105 , keyboard  107  and a suitable power source  109 . The communications device  102  includes a transmitter  104  and receiver  106 . The controller device  100  has communications software  108  operatively disposed in the memory  103  of the CPU and is operably associated with the receiver  106  and transmitter  104 . The controller device  100  includes controller software  110  resident in the memory  103  thereof and is operably associated with the gas metering device  22  and communications software  108  in a manner to enable gas flow rate detection and generate a transmission signal of the same. It is contemplated that the gas metering device  22  may be either external or integral to the controller device  100 . Additionally, the controller device  100  is operably connected to a control valve  26  as later described and the controller software  110  is further characterized to enable opening and closing the control valve  26 . 
     A remote based controller device  200  is operably disposed at a remote site R and includes a communications device  202 . The controller device  200  preferably is a CPU having a processor  201  with an associated memory  203 , display  205  and keyboard  207  and a suitable power source  209 . The communications device  202  includes a transmitter  204  and receiver  206 . The controller device  200  has communications software  208  operatively disposed in the memory  203  of the CPU and is operably associated with the receiver  204  and transmitter  206 . The communications software  208  is complementary coded to the communications software  108  to enable communication between the devices  100  and  200 . It is contemplated that communication may take place via radio, satellite, cellular tower or convention land line, wherein signals are transmitted between the devices  100  and  200 . 
     Via the connections recited above, the controller device  100  transmits flow rates in the downstream sales flow line  20  to the controller device  200 . The controller device  200  includes flow analysis and control software  210  resident in the memory  203  of the CPU which upon receiving the flow rate signals, manipulates the flow rate signals to produce optimum well shut in and flow periods. The flow analysis and control software  210  monitors flow rate signals over a predetermined period wherein a peak flow rate is observed after the well W has been shut in for a period of time, e.g., several hours. The controller device  200  transmits a signal to the controller device  100  causing the control valve  26  to close and shut in the well W for a predetermined period. After the predetermined period of time, the controller device  200  transmits a signal to the controller device  100  to cause the control valve  26  to open. Flow rates are sensed by the controller device  100  and transmitted to the controller device  200 . Peak flow rate and minimum flow rate are observed by the flow analysis and control software  210 . When the flow rate drops below a predetermined level in the well W, the flow analysis and control software  210  causes the controller device  200  to transmit a signal to the controller device  100  to shut in the well W and the pressure is allowed to build in the well W. This process is repeated and the flow analysis and control software  210  learns the optimum shut in time in order to achieve maximum peak flow rates. Also, the flow analysis and control software  210  learns the diminished flow rates of the well W. 
     This learning process is depicted in FIG. 2 wherein the well W is shut in using different time periods until the maximum flow rate is achieved. Once learned, the flow analysis and control software  210  causes the controller device  200  to transmit a signal to the controller device  100  to fix the shut-in and open times in accordance with the learned maximum rate and minimum flow rate. The controller device  100  thereafter periodically transmits flow rate signals to the controller device  200  for purposes of determining the production of the well W and further attenuation using the flow analysis and control software  210 . 
     While the flow analysis and control software  210  is depicted on the remote controller device  200 , it is contemplated that the same can be integrated into the controller device  100  as seen in FIG. 1 a . However, the remote site controller device is employed as it will serve as a hub which will control a large number of wells from a common site. 
     In this regard, it is another aspect of the invention that this well W production information be transmitted by the controller device  200  to an Internet web site  300  wherein the production information is posted for purposes of sale. Prior hereto, marginal well owners were forced to deal with third party marketers which bought the well production at a low cost, pooled a group of wells and sold the production to the consumer. By providing the present invention, this obviates the need for third party marketers. Now, owners of one or a few marginal wells can sell their production on an equal footing with large producers and gain comparable market rate as large producers while providing the consumer a potentially lower cost of goods. 
     The invention also includes a restricted region or orifice  23  which is formed in the downstream sales flow line  20 . A pressure differential control (PDC)  24  is operably associated with the downstream sales flow line  20  between the gas metering device  22  and the fluid and gas separator  16  and is shown in one aspect for sensing pressure differential in the downstream sales flow line  20  about the orifice  23 . The control valve  26  is operably disposed in the upstream flow line  12  and is operably controllably connected to the PDC  24  in a manner to permit regulated flow through the upstream flow line  12  at a predetermined amount in response to the sensed pressure differential. Optionally, the PDC  24  may include a timer device  28  which can also be used alone or in combination to control the control valve  26  to restrict and open at a predetermined time in accordance with the predetermined flow characteristics of the well W, i.e. its natural flow rate. Here, the controller device  100  is preferably operably connected to the PDC  24  and employs the use of a controlled transfer valve  44  hereinafter described to open and close the control valve  26 . It is also recognized that the controller device  100  may be directly connected to control valve  26  employing either pneumatic or electrical means for operation thereof. Optionally, the PDC  24  may be connected to another pressure sensor  45  on the upstream flow line  12  which may be used in establishing the predetermined flow characteristics of the well W. 
     The PDC  24  is equipped with means  30  for sensing when the pressure differential. The sensing means  30  can be mechanically or electrically based. In this regard, the sensing means  30  is operably connected to the controlled transfer valve  44  which is connected to one end  36  of a line  48  which sends a supply gas as a signal to the inlet control valve  26  for operation thereof. This supply gas emanates from a line  32  which is operably connected to a scrubber  33 . The scrubber  33  is in turn operatively connected to a line  50  having a regulator  35  therein. The line  50  is operably connected to the downstream flow line  20  to receive gas therefrom. The sensing means  30 , includes a pressure transducer  38  which is operably connected to the downstream sales flow line  20  having two pressure sensors  37  and  39  operably employed on the downstream flow line  20  about the orifice  23  in order to sense the amount of pressure differential about the orifice  23 . The components aid to regulate the supply of gas in the downstream flow line  20 . 
     As the PDC  24  senses pressure differentials above or below a predetermined threshold range, the PDC  24  sends a supply signal to the control valve  26  via a transfer valve  44  causing it to restrict or open accordingly. For example, when fluids F and gas G are flowing in the upstream flow line  12 , and the flow of gas G decreases, then flow decreases in the downstream sales flow line  20 . The PDC  24  senses the decrease in gas G flow and further opens the control valve  26 . This enables fluids F and gas G to enter the separator  16  faster and reduces back-pressure in the well W which would normally cause fluids F to fall back down the well W. Without this immediate and preferably automatic opening of the control valve  26  which relieves this condition, the fluids F would begin falling back into the well W before reaching the surface. Conversely, as flow in the upstream flow line  12  increases, flow in the downstream sales flow line  20  increases which initiates the PDC  24  to actuate the control valve  24  to restrict, thus keeping the flow conditions at an optimum to lift fluids F and for a longer period and also prevent over-ranging the meter  22 . This volume flow control keeps gas G at a rate which is not too fast or slow, but sufficient to provide lift of the fluid F. Optimal flow can be achieved and is reflected in FIG.  3 . 
     It is important to note that if the proper flow rates are not maintained, the fluids tend to lay against the tubing wall and won&#39;t come to the surface. As previously stated, the natural flow rate can be determined as described above as a function of a particular well&#39;s original natural geological characteristics and this flow rate is what is ideally attempted to be maintained by the PDC  24 . 
     Since the gas G expands as it moves toward the surface of the well W, the fluid F is necessarily drawn to the top with the gas G and the rate is necessarily a function of the gas G maintained in the fluid F. The separator  16  affects the optimal recovery by virtue of separating the gas G from the fluid F. Accordingly, an aim of the invention is to maintain an acceptable flow rate which optimally promotes fluid F and gas G flow in a manner which avoids the deleterious effects of spiking caused by restricting flow of the well W. The PDC  24  thus is employed in the present invention to keep the flow rate in the predefined measurable range within the down stream sales flow line  20 . 
     Additionally, chemical and biochemical additives  40  can be added to further enhance recovery production. Such additives  40  can be liquid or solid type, such as micro-organisms, foaming agents or viscosity modifiers which are delivered to the bottom of the well W by a tubing  42 , for example. This injection string of tubing  42  can be sized so it will displace part of the flow capacity which permits the siphoning action or critical flow rates to be created with less force in the well formation than would be required in a more productive well. An electrically operated control valve  41  is disposed within the tubing  42  and is operably connected to the controller device  100  via an electrical line  43 . The controller device  200  can also control the operation of adding additives  40  from the remote site via flow analysis and control software  210 . 
     The method of the present invention includes the steps of controllably delivering fluid and gas from a well in a single inlet flow path to a separator, separating the fluid from the gas into two separate outlet flow paths from the separator, sensing flow rate in the gas outlet flow path, employing a controller device to determine peak flow rate, diminished flow rate and optimal shut-in period and open period of the well. The method also includes comparatively sensing pressure of gas in the outflow path about a restricted region in a downstream sales flow line, and controllably regulating flow rate of the fluid and the gas in the inlet path in response to the sensed pressures. Additionally, pressure is sensed by sensor  45  in the upstream flow line or timed controlled of the flow restriction can be employed to control the proper pressure for obtaining optimal flow conditions. Additionally, the method further includes the adding of a flow enhancing additive to the well. 
     By so providing the present invention, there is realized enhanced recovery of fluid and gas. The present invention provides for an enhanced method and apparatus for controlling the metered gas which is recovered. The present invention provides for a new mechanism by which marginal well gas can be marketed and sold with greatest efficiency. 
     The above described embodiment is set forth by way of example and is not for the purpose of limiting the present invention. It will be readily apparent to those skilled in the art that obvious modifications, derivations and variations can be made to the embodiments without departing from the scope of the invention. Accordingly, the claims appended hereto should be read in their full scope including any such modifications, derivations and variations.