Apparatus for adding a selected additive into a mixture

Claims

What is claimed is:

1. An apparatus for adding a selected additive into a mixture, comprising:

first container means for storing a first additive, said first container means including a first additive outlet;

second container means for storing a second additive, said second container means including a second additive outlet;

first metering means for moving a substance at a controlled rate, said first metering means including a first metering inlet and a first metering outlet;

second metering means for moving a substance at a controlled rate, said second metering means including a second metering inlet and a second metering outlet;

mixing means for mixing a plurality of substances into a mixture, said mixing means including a plurality of additive inlets;

first connector means for changeably connecting the respective additive outlet of a selected one of said first and second container means to the respective metering inlet of a selected one of said first and second metering means for communicating the respective additive from the selected one of said first and second container means to the selected one of said first and second metering means to be the substance moved thereby; and

second connector means for changeably connecting the respective metering outlet of the selected one of said first and second metering means to a selected one of said plurality of additive inlets of said mixing means for communicating the selected one of said first and second metering means with said mixing means through the selected one of said plurality of additive inlets, thereby for providing the respective additive of the selected one of said first and second container means as a substance to be mixed in said mixing means.

2. An apparatus as defined in claim 1, wherein:

said first connector means includes a first hose including coupling means for releasably coupling to the respective additive outlet of the selected one of said first an second container means, and coupling means for releasably coupling to the respective metering inlet of the selected one of said first and second metering means; and

said second connector means includes a second hose including coupling means for releasably coupling to the respective metering outlet of the selected one of said first and second metering means, and coupling means for releasably coupling to the selected one of said plurality of additive inlets of said mixing means.

3. An apparatus as defined in claim 2, further comprising a truck having said first and second container means, said first and second metering means and said mixing means mounted thereon, said truck including storage means for receiving said first hose when said coupling means thereof are released from the respective additive outlet and the respective metering inlet and for receiving said second hose when said coupling means thereof are released from the respective metering outlet and the selected one of said plurality of additive inlets.

4. An apparatus as defined in claim 1, wherein:

said mixing means includes:

a blending tub;

a pump;

a flowmeter;

first conduit means for conducting a fluid flow from said blending tub to said pump; and

second conduit means for conducting a fluid flow from said pump to said flowmeter; and

said plurality of additive inlets include:

first coupling means, communicated into said blending tub, for releasably coupling with said second connector means;

second coupling means, communicated into said first conduit means, for releasably coupling with said second connector means; and

third coupling means, communicated into said second conduit means, for releasably coupling with said second connector means.

5. An apparatus as defined in claim 4, wherein:

said apparatus further comprises a truck having said mixing means mounted thereon;

said first container means includes a first tank mounted on said truck;

said second container means includes a second tank mounted on said truck;

said first metering means includes a first additive pump mounted on said truck;

said second metering means includes a second additive pump mounted on said truck;

said first connector means includes a first hose, carried on said truck, for connecting a selected one of said first and second tanks in fluid communication with a selected one of said first and second pumps; and

said second connector means includes a second hose, carried on said truck, for connecting the selected one of said first and second pumps to a selected one of said first, second and third coupling means.

6. An apparatus as defined in claim 5, further comprising:

gate means, mounted on said truck in overlying relation to said blending tub, for providing a variable opening through which a particulate material can be dropped into said blending tub;

monitoring means, mounted on said truck, for monitoring said first metering means, said second metering means and said flowmeter and for providing control information in response thereto, said control information including gate means position indicia and additive concentration indicia;

first manual control means, mounted on said truck, for moving, in response to manual control by an operator, said gate means to the gate means position indicated by said gate means position indicia; and

second manual control means, mounted on said truck, for controlling, in response to manual control by an operator, the selected one of said first and second pumps to operate at a rate which delivers additive so that the additive concentration indicia provided by said monitoring means equals a desired concentration of the additive.

7. An apparatus as defined in claim 1, wherein:

said first metering means includes a pump connected between said first metering inlet and said first metering outlet; and

said second metering means includes a gravity flowmeter connected between said second metering inlet and said second metering outlet.

8. An apparatus as defined in claim 1, wherein:

said apparatus further comprises a truck having said mixing means mounted thereon;

said second container means includes a second tank mounted on said truck;

said first metering means includes a first pump mounted on said truck;

said second metering means includes a second pump mounted on said truck;

said first connector means includes a first hose, carried on said truck, for connecting a selected one of said first and second tanks in fluid communication with a selected one of said first and second pumps; and

said second connector means includes a second hose, carried on said truck, for connecting the selected one of said first and second pumps to a selected one of said plurality of additive inlets.

9. An apparatus as defined in claim 1, wherein:

said mixing means includes a blending tub; and

said apparatus further comprises:

gate means, mounted in overlying relation to said blending tub, for providing a variable opening through which a particulate material can be dropped into said blending tub;

monitoring means for monitoring said first metering means, said second metering means and said mixing means and for providing control information in response thereto, said control information including gate means position indicia and additive concentration indicia;

first manual control means, responsive to manual control by an operator, for moving said gate means to the gate means position indicated by said gate means position indicia; and

second manual control means, responsive to manual control by an operator, for controlling the selected one of said first and second metering means to operate at a rate which delivers additive so that the additive concentration indicia provided by said monitoring means equals a desired concentration of the additive.

10. An apparatus as defined in claim 9, wherein said monitoring means includes:

a first computer and display unit, comprising:

means for receiving an electrical signal indicating a flow rate of the mixture;

means for receiving a manually input electrical signal indicating a desired concentration of particulate material within the mixture;

means, responsive to the indicated flow rate and the indicated desired concentration, for computing and displaying a gate means position at which the indicated desired concentration of particulate material is obtained for the indicated flow rate; and

means, responsive to the indicated flow rate and the indicated desired concentration, for computing and transmitting an electrical signal representing a clean mixing flow rate of the mixture compensated to delete the particulate material component of the mixture; and

a second computer and display unit, comprising:

means for receiving from said first computer and display unit the electrical signal representing a clean mixture flow rate;

means for receiving from said first and second metering means electrical signals representing flow rates of additives moved by said first and second metering means; and

means, responsive to the represented clean mixture flow rate and the represented flow rates of additives, for computing and displaying the concentrations of the represented additives in the mixture.

11. A portable apparatus for mixing a liquid additive and a proppant with a base fluid to prepare at a well site a mixture for use in a well, said apparatus comprising:

liquid additive storage means for providing a reservoir for a liquid additive;

liquid additive metering means for providing a controlled rate flow of a liquid additive from said liquid additive means;

proppant metering means for providing a controlled rate flow of a proppant;

mixing means for receiving the controlled rate flow of a liquid additive and the controlled rate flow of a proppant and for mixing the controlled rate flows with a flow of a base fluid to provide a flow of a mixture;

first computer means, including means for receiving a desired proppant concentration factor and responsive to said mixing means and to a received desired proppant concentration factor, for computing information with which to control said proppant metering means and for computing a clean flow rate value for the mixture excluding the proppant; and

second computer means, responsive to the clean flow rate value and to said liquid additive metering means, for computing a liquid additive concentration value with which to control said liquid additive metering means.

12. An apparatus as defined in claim 11, wherein:

said first computer means includes:

a first keypad for entering a desired proppant concentration factor;

a first display for displaying a rate of flow of the flow of mixture provided by said mixing means;

a second display for displaying, as the information with which to control said propant pant metering means, a scale number corresponding to a position setting of said proppant metering means for obtaining the desired proppant concentration designated by an entered and received desired propant concentration factor; and

a first microcomputer connected to said first keypad and said first and second displays, said first microcomputer including said means for receiving a desired propant concentration factor; and

said second computer means includes:

a second keypad;

a third display for displaying a first computed liquid additive concentration value;

a fourth display for displaying a second computed liquid additive concentration value; and

a second microcomputer connected to said second keypad and to said third and fourth displays and connected in communication with said first microcomputer.

13. An apparatus as defined in claim 11, wherein said first computer means includes a microcomputer programmed for calculating a clean flow rate value for the mixture excluding the proppant in response to:

clean flow rate value=(flow rate of the flow of the mixture)/(1+XY),

where

X=a proppant coefficient received by said microcomputer and

Y=a desired proppant concentration factor received by said microcomputer.

14. An apparatus as defined in claim 11, wherein:

said liquid additive storage means includes a plurality of additive outlets;

said liquid additive metering means includes a plurality of metering inlets and a plurality of metering outlets and means for communicating said plurality of metering inlets and said plurality of metering outlets;

said mixing means includes a plurality of additive inlets; and

said apparatus further comprises:

first connector means for connecting a selected one of said additive outlets to a selected one of said metering inlets; and

second connector means for connecting a selected one of said metering outlets to a selected one of said additive inlets.

15. An apparatus as defined in claim 11, further comprising a truck including:

a driver's cab;

a wheel-mounted chassis having said cab, said liquid additive storage means, and said liquid additive metering means mounted thereon;

lift means, having said mixing means and said proppant metering means mounted thereon and connected to said chassis, for moving said mixing means and said proppant metering means between a raised position adjacent said chassis and a lowered position adjacent ground upon which said truck sits; and

a control panel mounted on said chassis and having said first and second computer means mounted therein.

16. An apparatus as defined in claim 15, wherein:

said mixing means includes a tub mounted on said lift means; and

said proppant metering means includes a gate disposed above said tub and hydraulically adjust able to a selected position relative to said tub in response to the computed information with which to control said proppant metering means to define a window of adjustable size, through which window the controlled rate of flow of a proppant is provided.

BACKGROUND OF THE INVENTION

This invention relates generally to apparatus and methods for adding one or more selected additives into a mixture and more particularly, but not by way of limitation, to a portable apparatus and a method for mixing a liquid additive and a proppant with a base liquid to prepare at a well site a mixture for use in a well.

During construction activities, for example, mixtures of materials sometimes need to be prepared. With specific reference to drilling and completing an oil or gas well, acidizing and fracturing fluids, as well as cements and gels, sometimes need to be provided at the well site for well-known purposes. Such mixtures can be needed in various quantities and compositions.

To provide such a mixture to a well site, a batch of the anticipated desired composition and quantity can be prepared and then transported to the well site. An example of this is a 4000-gallon bulk acid transport truck. Alternatively, the components of the ultimate mixture can be carried to the well site and there mixed in separate equipment which has also been transported to the well site. These techniques typically produce batches of the mixture. This can produce waste, and expense to the customer, if the well cannot be prepared in time to use the batch or if significantly less than the entire batch is needed in the well. These techniques also typically require more than one piece of equipment to be transported to the well site. This, too, can increase the costs to the customer by way of the additional equipment and the additional manpower to operate it.

In view of these characteristics of the techniques by which mixtures are typically provided to a well site, it would be desirable to provide a technique wherein local mixing "on the fly" (i.e., as the mixture is needed and pumped into the well) would be performed for a specific job. This would obviate the necessity of anticipating ultimate needs and specific timing as must be done when a batch is premixed well before it is actually needed. Creating the needed mixture locally and on the fly would thus likely prevent the waste which can result from the technique whereby a mixture is batched beforehand. To obviate the need for multiple pieces of equipment to be transported separately to the well site, it would also be desirable for the new technique to be a single compact, portable integrated system capable of transporting the needed components, mixing them as needed, and providing control information by which the mixing process can be controlled.

Although it would be desirable to have such a single compact, portable integrated system of any suitable type, it would be preferred to have such a system be versatile so that a variety of mixtures can be produced. This versatility should include the ability to have individual additives or combinations of additives selected for use in producing the mixture. Such versatility should also include the ability to meter one or more selected additives within different, selectable metering ranges. Such versatility should also include the ability to select the location where a selected additive is to be input into the mixing system.

Such an integrated system should also provide for relatively easy control so that operator tasks such as reading and matching meters and consulting additive concentration charts are no longer necessary. For example, where a particulate proppant and one or more liquid additives are to be added into a mixture, computer technology should be used to compute and display a gate setting and actual concentration values. The gate setting would be used to set a proppant gate by which the amount of proppant added into the mixture is controlled, and the actual concentration values would be used to control the metering of the selected additive(s).

Finally, an apparatus and method meeting each of the foregoing needs should preferably also be relatively simple to construct or implement, and require relatively low maintenance and cost.

SUMMARY OF THE INVENTION

The present invention overcomes the above-noted and other shortcomings of the prior art by providing a novel and improved apparatus and a novel and improved method for adding one or more selected additives into a mixture. Although one or more of the needs mentioned in the preceding section may be met by one or more prior techniques for providing mixtures of materials at a location where needed, such as at a well site, it is believed that no prior system satisfies all the stated needs in the manner in which the present invention satisfies them.

The present invention provides a single compact, portable integrated material transport and mixing system which satisfies all the aforementioned needs. In a preferred embodiment, a truck carries tanks of liquid additives and sacks of dry additive which are to be mixed, on the fly as the resultant mixture is needed and used, in a mixing system also carried on the truck. A selected tank is changeably connected to a selected pump which is changeably connected to a selected input of the mixing system. Other such changeable connections are possible with other inputs disposed at various locations of the mixing system. Flow rates are monitored by microcomputers which use the flow rates and a manually input desired dry additive concentration factor and a manually input dry additive coefficient to compute and display information in response to which an operator manually controls the metering of the liquid and dry additives. These computer-based monitoring and information generating functions are implemented to obviate the need for the operator to read and match needle indicators and then consult one or more charts to learn what the concentrations are or what settings should be made to obtain desired concentrations. The present invention is constructed in the preferred embodiment to be relatively simple and low cost and to require relatively low maintenance.

More generally, the present invention provides an apparatus for adding a selected additive into a mixture. The apparatus comprises: first container means for storing a first additive, the first container means including a first additive outlet; second container means for storing a second additive, the second container means including a second additive outlet; first metering means for moving a substance at a controlled rate, the first metering means including a first metering inlet and a first metering outlet; second metering means for moving a substance at a controlled rate, the second metering means including a second metering inlet and a second metering outlet; mixing means for mixing a plurality of substances into a mixture, the mixing means including a plurality of additive inlets; first connector means for changeably connecting the respective additive outlet of a selected one of the first and second container means to the respective metering inlet of a selected one of the first and second metering means for communicating the respective additive from the selected one of the first and second container means to the selected one of the first and second metering means to be the substance moved thereby; and second connector means for changeably connecting the respective metering outlet of the selected one of the first and second metering means to a selected one of the plurality of additive inlets of the mixing means for communicating the selected one of the first and second metering means with the mixing means through the selected one of the plurality of additive inlets, thereby for providing the respective additive of the selected one of the first and second container means as a substance to be mixed in the mixing means.

In a preferred embodiment the first connector means includes a first hose including coupling means for releasably coupling to the respective additive outlet of the selected one of the first and second container means, and the first hose also includes coupling means for releasably coupling to the respective metering inlet of the selected one of the first and second metering means. The second connector means of this embodiment includes a second hose including coupling means for releasably coupling to the respective metering outlet of the selected one of the first and second metering means, and it also includes coupling means for releasably coupling to the selected one of the plurality of additive inlets of the mixing means. This embodiment further comprises a truck having the first and second container means, the first and second metering means and the mixing means mounted thereon, which truck includes storage means for receiving the first hose when the coupling means thereof are released from the respective additive outlet and the respective metering inlet and for receiving the second hose when the coupling means thereof are released from the respective metering outlet and the selected one of the plurality of additive inlets.

In a particular embodiment, the present invention provides a portable apparatus for mixing a liquid additive and a proppant with a base fluid to prepare at a well site a mixture for use in a well, which apparatus comprises: liquid additive storage means for providing a reservoir for a liquid additive; liquid additive metering means for providing a controlled rate flow of a liquid additive from the liquid additive means; proppant metering means for providing a controlled rate flow of a proppant; mixing means for receiving the controlled rate flow of a liquid additive and the controlled rate flow of a proppant and for mixing the controlled rate flows with a flow of a base fluid to provide a flow of a mixture; first computer means, including means for receiving a desired proppant concentration factor and responsive to the mixing means and to a received desired proppant concentration factor, for computing information with which to control the proppant metering means and for computing a clean flow rate value for the mixture excluding the proppant; and second computer means, responsive to the clean flow rate value and to the liquid additive metering means, for computing a liquid additive concentration value with which to control the liquid additive metering means.

The method of the present invention comprises the steps of: transporting to the well site on a single vehicle a plurality of containers each containing a respective liquid additive and each including an additive outlet, a plurality of liquid additive metering means for providing a metered flow of a liquid additive each including a metering inlet and a metering outlet, and mixer means for mixing a metered liquid additive and a base liquid, which mixer means includes a plurality of additive inlets; manually connecting, at the well site, with a first hose the additive outlet of a selected one of the containers and the metering inlet of a selected one of the liquid additive metering means; manually connecting, at the well site, with a second hose the metering outlet of the selected metering means and a selected one of the additive inlets of the mixing means; and controlling, at the well site, the selected metering means to provide a metered flow of the liquid additive of the selected one of the containers so that provided in the mixing means is a mixture having a desired concentration of the liquid additive of the selected one of the containers.

In the preferred embodiment this method further comprises the steps of: setting the size of an opening defined above a tub of the mixing means, including: entering a desired dry additive concentration factor into a computer carried on the single vehicle; determining in the computer a flow rate of the mixture; calculating in the computer, in response to the desired dry additive concentration factor and the flow rate of the mixture, a desired flow rate of dry additive to obtain the dry additive concentration indicated by the desired dry additive concentration factor; displaying indicia representing the calculated desired flow rate of dry additive; and manually adjusting, in response to the displayed indicia, a movable gate disposed above the tub of the mixing means so that the size of the opening defined above the tub is thereby set; an