Patent Application
20240167371
The disclosure relates generally to applying electrical treatment to dead gas wells blocked by water. Dead gas wells are wells that are no longer capable of producing gas economically. Such water blockage occurs when the surrounding region around a wellbore is in contact with water for a long period of time. This long period of contact results in water saturation increasing relative to the gas saturation. Consequently, the pore spaces of the reservoir become occupied with water blocking the flow of gas and reducing the gas production.
Accordingly, there exists a need for an electrical treatment to enlarge the pore spaces facilitating production of gas recovering the dead gas wells.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In general, in one aspect, embodiments disclosed herein relate to a system for electrical treatment in a reservoir with gas wells, the system including a first well in the reservoir configured to act as an electrode, the reservoir having a plurality of pore spaces saturated by water, and a second well in the reservoir configured to act as a second electrode hydraulically connected to the first well. A power unit is connected to the first well and the second well by a cable configured to emit an electric current to the first well and the second well into the reservoir. The electric current enlarges the plurality of pore spaces in the reservoir, facilitating a production of gas from the water. A transformer is connected to the power unit by the cable, the transformer being configured to step down a voltage from a power supply to the power unit. The power supply is connected to the transformer by the cable.
In general, in one aspect, the invention relates to a method for electrical treatment in a reservoir with gas wells. The method involves supplying power by a power supply connected to a transformer by a cable to a power unit, wherein the transformer is configured to step down a voltage from the power supply to the power unit, applying an electric current by the power unit through a first well and a second well into the reservoir, wherein the first well, configured to act as a first electrode, is hydraulically connected to the second well that is configured to act as a second electrode, enlarging a plurality of pore spaces in the reservoir by application of the electric current, wherein the plurality of pore spaces is saturated with water, and releasing water from the plurality of pore spaces by the enlargement of the plurality of pore spaces.
Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
Specific embodiments of the disclosed technology will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.
In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.
Embodiments disclosed herein relate to methods for reviving dead gas wells from water blockage by the application of electrical treatment. Water blockage hinders the ability to extract water from a gas well and formation damage may occur. In one or more embodiments, the electrical treatment to revive the dead gas wells is initiated by a power supply emitting electric current. After current is applied to a well head, the charge propagates through metallic casing along the well until it reaches the pay zone delivering to the reservoir. When electric current is applied, a mechanical destruction of the blocked pore space occurs, which results in an increase in permeability. The increase in pore throat radius creates a space for water to move and be released from pore spaces. The occurrence of partial electrolysis due to passing of electric current leads to gas bubbles formation from released water. Electric current also improves the connectivity of released water droplets for easy mobilization and removal.
Embodiments of the present disclosure may provide at least one of the following advantages. Electrical treatment to reverse the unforeseen process of water blockage, recover dead gas wells to produce desired gas results in prolonging the life of the gas wells. Further, electro-enhanced oil recovery (EEOR) has a low carbon footprint and sustainable eco-friendly.
Further,
In one or more embodiments, an electrical treatment is initiated by the power supply (112) emitting electric current to the transformer (116). The transformer (116) steps down the electric current to the power unit (114). The electric current is applied from the power unit (114) to the first well (100) and the second well (102). The first well (100) and second well (102) may act as electrodes by the polarization of the power unit (114). The power unit (114) may conduct positive polarity to the cathode and negative polarity to the anode by connecting the metallic casing of the well to the power unit (114) through the power cable (100). The power unit (114) may be a battery. The electric current may propagate through metallic casing in the first well (100) and the second well (102) until a pay zone delivering to the reservoir (104). The pay zone may be part of the reservoir (104) that contains hydrocarbons.
When applying electrical treatment, a high voltage power supply (112) may be necessary for the source of energy. An example of the high voltage may be 200 to 500 KVA. The transformer (116) may lower the voltage to a required value. An example of the required voltage may be 100-120 V. The power cable (110) lines may include characteristics to decrease the amount of electricity lost while traveling through the cables. For example, the power cable (110) may be flexible, be single-core, be four thin copper wires with a cross section of 120 square mm, have a rubber or plastic coating, and not exceed 500 m in length. The arrows in
Initially, power is supplied to a transformer (116) by a power supply (112) in a system (Block 1500). The power supply (112) may be connected to the transformer by a power cable (110). The transformer (116) may by connected to a power unit (114) by the power cable (110). The power supply (112) may be disconnected from the transformer (116) at a predetermined voltage by a safety device (118). The safety device may be protection controlled automatic equipment. In Block 1502, the transformer (116) steps down voltage to the power unit (114). In Block 1504, an electric current is applied by the power unit (114) through a first well (100) and a second well (102) into the reservoir (104). The first well (100) and the second well (102) may act as electrodes. Specifically, the first well (100) acts as a first electrode, and the second well (102) acts as a second electrode, or vice versa, depending on the polarity connection of the power cable to the power supply (112). For example, the first well (100) may be a cathode and the second well (102) may be an anode. The first well (100) and the second well (102) may have metallic casing that acts as a conductor for electric currently supplied by the power cable (110). The first well (100) and the second well (102) may be gas wells. The reservoir (104) may have a higher water saturation relative to gas saturation. The first well (100) and the second well (102) are hydraulically connected. The electric current may be applied to a wellhead of the first well (100) and the second well (102). The electric current may propagate through the metallic casing all the way to a pay zone delivering to the reservoir (104).
In Block 1506, a plurality of pore spaces (106) blocked by water in the reservoir (104) are enlarged. The plurality of pore spaces (106) may be saturated with water. The local electric current may pulse in the reservoir (104) to enlarge the throats of the pore spaces (106) leading to water releasing through porous media. In Block 1508, the plurality of pore spaces (106) release the water by the enlargement of the pore spaces (106). In Block 1510, a plurality of gas (1104) bubbles are formed from the released water. The electric current may cause partial electrolysis forming gas droplets or bubbles (1104) from some of the released water. In Block 1512, the gas (1104) bubbles are extracted and produced from the enlargement of the pore spaces (106) by the electrical treatment. The gas (1104) bubbles are produced and extracted from the first well (100) and the second well (102). The electrical treatment method may be moved from one reservoir (104) to another for continual application.
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112(f) for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
