WO2018200710A2

WO2018200710A2 - Compositions and methods for enhancing oil and/or gas production from water-contaminated wells

Info

Publication number: WO2018200710A2
Application number: PCT/US2018/029421
Authority: WO
Inventors: Rob MCNAUGHTON; Nick KOSTER
Original assignee: Hk Ip Llc
Priority date: 2017-04-25
Filing date: 2018-04-25
Publication date: 2018-11-01
Also published as: WO2018200710A3

Abstract

Disclosed herein are methods, compositions, and systems useful in treating oil and gas wells that may be contaminated with water, the methods and compositions are useful in removal of water from the well and restoring production of oil and/or gas. In some cases, the treated well may have been damaged by addition of water and/or influx of geologic water. In other embodiments, the well may be treated before or during the use of water to aid in fracturing "tight" oil and gas geologic formations, and improving the conductivity of the geologic formation. The disclosed methods and compositions may include placing surfactants near or in water contaminated geologic formation, reducing the surface tension of water found in the formation; creating micro fissures within the formation; dissolving waxes, asphaltines, and/or other contaminants; and/or heating of formation fluid.

Description

COMPOSITIONS AND METHODS FOR ENHANCING OIL AND/OR GAS

PRODUCTION FROM WATER-CONTAMINATED WELLS

CROSS-REFERENCE TO RELATED APPLICATION This application claims benefit of priority pursuant to 35 U.S.C. § 119(e) of U.S. provisional application No. 62/489,930 filed on April 25, 2017, the disclosure of which is incorporated herein in its entirety.

BRIEF DESCRIPTION

Disclosed herein are compositions, methods, and systems for aiding in migration, removal, and/or extraction of water from a geologic formation. In many embodiments, the water removed from the geologic formation may be naturally occurring, or may have been introduced to the formations e.g. during drilling of a wellbore or fracturing. In many embodiments, the disclosed compositions may comprise one or more of :

• an ester, for example methyl esters of various carboxylic acids (including but not limited to those commonly found in biodiesel);

• a turpene (or terpene; including e.g. pine oil containing alpha-pinene);

• an alcohol (including e.g. isopropyl alcohol);

• a halogen (including e.g. Iodine).

Proportions of the components above may be varied in producing the disclosed compositions. In some embodiments, the various component proportions may be modified based on the conditions present in the specific formation affected. In some embodiments, one or more of the disclosed components may be withheld from the composition.

The makeup of the disclosed composition may vary during the time it is introduced into the wellbore. In some embodiments, the components may be mixed and injected, together, into the well. In other embodiments, different components may be added separately. In some embodiments, an alcohol may be injected into a well alone, or in combination with another component, for example an acid; this may, in some embodiments be followed by another component, for example a halogen. In many embodiments, injection of one component may be separated from the next by injection of the ester, alone or in combination with another component. In many embodiments, separated injection of different components may aid in decreasing or delaying component interaction and/or reaction. Candidate oil and gas wells may be identified using a set of criteria, which may include the amount or percentage of "swelling clays," asphaltenes, and/or water in the formation, or the viscosity of the hydrocarbons. In many embodiments, a formation may comprise various layers or strata, which may have different characteristics (for example the concentration of swelling clay). In other embodiments, a formation may be generally homogeneous, comprising a more uniform makeup. In some embodiments, for example in the case of some horizontal bores, the formation may general refer to a single, generally horizontal layer through which the bore is drilled. Various other characteristics of the formation such as the porosity, permeability, and overall clay content may also play a role in determining the amount of water contamination, which may be present.

The method of introducing the disclosed fluid compositions to an affected well may vary. In most embodiments, however, the disclosed methods may usually include techniques very familiar to those who are skilled in the art of extraction of "tight" oil and gas from shale formations in North America. These techniques may help to ensure the fluid composition is distributed properly to and within the affected area to ensure the desired results occur.

Disclosed herein are methods, compositions, and systems related to increasing production from oil and gas wells. In many instances, hydrocarbon production may be low due to the presence of water. Water may act to lower hydrocarbon production by blocking migration of the hydrocarbon. In some cases, hydrocarbon migration may be reduced due to water damage in the formation, for example where the formation includes swelling clays and/or fines.

The disclosed methods, compositions, and systems are useful in treating wells to aid in removal of water from the well. In some cases, the treated well may have been damaged by addition of water. In other embodiments, the well may be treated before or during the use of water to fracture "tight" oil and gas geologic formations. The disclosed compositions, methods, and systems may also be useful in increasing oil and/or gas production through improving the conductivity of the formation. In some embodiments, chemical reactions and physical changes may occur within the well-bore and surrounding formations as a result of the disclosed methods and compositions, some of which may include, but are not limited to:

• Placing surfactants near or in the water contaminating clays; · Reducing the surface tension of water found in the formation;

• Creating micro fissures within the geologic formation;

• Dissolving of waxes, asphaltines, and other contaminants; and/or

• Heating of formation fluid. The disclosed methods, compositions, and systems may enhance productivity from wells to provide for long-term economically sustainable productivity. In many embodiments, the disclosed methods may aid in enhancing oil and/or gas recovery in an environmentally friendly manner.

DETAILED DESCRIPTION

As described above, the proportions of the components may vary depending on the type of water contamination and/or amount of water contaminating the formation. The proportions may also be varied depending on when the disclosed fluid composition is being used, for example prophylactically - that is where the fluid composition is applied to the formation prior to the reservoir being fractured/completed, or where the composition is applied after the reservoir/formation has been fractured/completed. Some components may be eliminated entirely depending on the characteristics of the formation.

Application After Fracturing has been completed

In the event that the well has been completed and oil/gas production is below expectations, a combination of some or all components can be injected into the well. In many embodiments, injection of the disclosed fluid composition may be aided by combining the composition with an inert gas. This may help to ensure the fluid composition is well distributed in the formation. In many embodiments, the disclosed techniques are familiar to those skilled in the art of completing oil/gas wells in "tight" formations, which may contain substantial amounts of oil and gas.

Hydrocarbon production from a wellbore may be difficult for a variety of reasons. For example, gas injection EOR, which is the dominant process for Enhanced oil recovery (EOR) used in the United States, may lead to difficulty in removing hydrocarbons. This process uses gases such as natural gas, nitrogen, or carbon dioxide (CO2) to help enhance oil recovery. Gas injection may also be referred to as "miscible flooding," describing the introduction of miscible gases into an oil reservoir. CO2 is the most commonly used gas because of its low cost and ability to reduce viscosity. In some cases, these methods may include introduction of an aqueous fluid into the wellbore and the surrounding formation. In some embodiments, the gas may include steam water.

Steam assisted gravity drainage (SAGD) is one example of a steam injection process for EOR. This process may be useful in reservoirs having heavy oil and/or in horizontal wells. For example, SAGD has been used in Alberta, Canada for recovery of heavy oil and recovery from tar sands. This process helps to introduce heat into the target reservoir or formation. In most cases, the injection of steam causes the oil to heat and expand, lowering its viscosity and allowing it to migrate to a production well. In some cases, the use of steam for thermal injection is problematic where the formation contains large amounts of clay or other hygroscopic material that may tend to trap the water and prevent migration of the oil. In general, thermal injection techniques have temporary effects, with the beneficial changes dissipating over time as the temperatures return to pre-injection levels, this dissipation may be accelerated where the formation comprises water and/or hygroscopic material that may prevent or inhibit recovery of hydrocarbons.

Hydraulic fracturing, or "fracturing," is a method used in the development of oil and gas. It is designed to increase access to trapped hydrocarbons. The method involves the introduction of quantities of "fracturing fluid" (usually comprising water, small particulate matter, and various chemicals) into a well bore. The fracture fluid is then forced, under pressure, into the geologic formation surrounding the well bore, with the particulate matter helping to keep the fissures and cracks open when the pressure is removed. These fissures and cracks act as conduits through which hydrocarbons trapped in the formation can travel into the well bore.

The use of methods that include water, for example SAGD and hydraulic fracturing with aqueous fluids, may introduce large volumes of water. In some cases, the presence of water can damage the well. For example, water may swell clay found in some geologic formations, or aid in movement of fines that result in lowering porosity and/or conductivity. This may render tight oil formations even tighter.

The disclosed fluid composition may be designed to enhance certain

characteristics of the fluid by varying the proportions of certain individual components. Each individual component may have a specific function for the enhancement of oil and gas production. In many embodiments, the disclosed components may be generally useful in aiding the removal of water and/or other contaminants from the target formation. As a result, the proportions of components in the fluid may vary depending on the amount of water contamination or other contaminants. In some embodiments, the individual components may be designed to interact with each other to enhance their effectiveness. In other embodiments, individual components may be effective without interaction with other components, and their effectiveness may be in contacting one or more individual contaminants.

In some embodiments, biodiesel may be the source of the esters. In these embodiments, the use of biodiesel as the source of esters, in particular methyl esters, may provide for additional benefits. In some embodiments, the esters and/or biodiesel may act as a solvent to remove one or more of the above-described contaminants. The disclosed esters, which may be provided by biodiesel, may also chemically react with water to create one or more alcohols and acids (e.g. fatty acids). In some embodiments, this reaction may be aided if the water has a pH less than 7.0, or the biodiesel is modified to have a pH less than about 7.0. In some embodiments, the biodiesel's reaction may help to release a surfactant, or one or more components of the biodiesel or composition may become a surfactant, wherein the surfactant may be useful to help lower the surface tension of the water that may remain in the well. In some cases, the remaining water may, or may not, be trapped within swelling clays. When Biodiesel acts as a solvent it may be effective in removing various hydrocarbon-based contaminants. Hydrocarbon- based contaminants may also affect the conductivity of the reservoir. For example, biodiesel may remove asphaltines from well bore perforations, this removal may also help to enhance conductivity of oil, and gas into the well bore.

In the event that biodiesel reacts with water in an acidic environment, the reaction may cause the alkyl esters within the biodiesel to breakdown into primarily two types of components, which may be fatty acids with C1-C5 carbon chains and an alcohol, for example methanol. Both these components are miscible in water and may also contribute to the lowering the surface tension of water. Lowering of water's surface tension may aid moving or mobilizing the water out of the contaminated formation. Mobile water may more easily exit "swelling clays" and reducing their size. Reducing the size of swelling clays may help to increase the conductivity of the formation. Additionally, the production of methanol during this reaction may provide for a significant expansion of the fluid that may help to create micro fissures in the formation. This expansion may also contribute to enhancing conductivity of the reservoir.

Turpenes, or terpenes, which may include biologically-derived organic compounds, for example alkenes, such as cyclic compounds, for example cyclohexenes, comprising one or more carbon-carbon double bonds. Terpenes may also help remove water and alter the chemical and/or physical characteristics of the formation. Turpenes, which may contain alpha-pinene, can play multiple roles in the disclosed fluid composition. These roles may include but are not limited to, the dissolving of high viscosity/solid hydrocarbons, such as asphaltines, or waxes. This removal may also help to improve the conductivity of the reservoir. Many turpenes are also soluble in simple alcohols, but have a higher boiling temperature or boiling point than simple alcohols. This difference in boiling point may help to allow simple alcohols (for example those that may be added to the disclosed composition and/or created by reactions within the well bore) to be delivered into relatively high temperature and high-pressure reservoirs easily. In other embodiments, the disclosed compositions and methods may be used to help remove water from low pressure formations. Use of these components may help to allow alcohols within the composition to reduce the surface tension of water. In many embodiments, individual components may act as surfactants to increase the mobility of free and/or trapped water within the reservoir.

In some embodiments, the conditions within the formation may benefit from faster movement/mobilization/removal of water, for example water near the well bore. In these cases, an increase in the proportion of simple alcohols within the fluid may be beneficial. Additionally, these cases may also benefit from a corresponding

(proportional or non-proportional) increase in the amount of terpenes in the composition. In these cases, terpenes such as alpha-pinene may improve the manner in which the fluid places the simple alcohols near the water contamination.

Turpenes, such as alpha-pinene or others, may be highly reactive with one or more halogens, for example iodine. Reaction with a halogen may help in creating an exothermic reaction and generating energy, in some embodiments about 156kJ/mole of energy. In addition to generating energy /heat, the reaction with halogen may create a halogen halide, for example where the reaction is with iodine the resulting compound is HI, Hydrogen Iodide. In these embodiments, HI is a gas, and an acid with a pH of 1.0 in aqueous solutions. In some embodiments, the reaction of alpha-pinene would create HI as a gas, which would react with water within the formation, creating an acidic solution. The resulting acid may, in turn, react with one or more esters, for example methyl esters from the biodiesel, thereby assisting with further removal of water contamination as discussed above.

Assessment of Effectiveness of application of fluid

Various measures may be used to assess effectiveness of the fluid. In terms of improvement of an existing well that has been previously contaminated with water, any increase in production after treatment with the fluid can be directly attributed to the application of the fluid. However, in the event that mechanical factors or operational difficulties unrelated to the application of the fluid occur other measurements may be useful in determining the effectiveness of the disclosed fluid compositions and methods. In some embodiments, one such measurement may be the amount of surfactants, for example surfactants in the form of C1-C5 fatty acids or simple alcohols, present in the flow backwater. When the amounts of C-l- C-5 fatty acids and/or simple alcohols present in flow back water are compared to the amounts present prior to the introduction of the fluid, it may be a clear indication that the improvement in water mobility within the formation is due to the disclosed methods, compositions, and/or systems.

Claims

CLAIMS What is claimed is:

1. A fluid composition comprising:

75% or less alcohol; and

25% or less of terpene, wherein the composition is sufficient to effectively deliver the alcohol into a formation without incurring significant difficulty in mechanical pumping of said fluid.

2. The fluid composition of Claim 1, further comprising a methyl ester.

3. The fluid composition of any of Claims 1-2, further comprising a halogen.

4. The fluid composition of any of claims 1-3, wherein the alcohol is isopropyl alcohol, the terpene is alpha-terpinene, the methyl ester is from biodiesel, and the halogen is iodine.

5. The fluid composition of any of claims 1-4, further comprising a proppant comprising of citric acid and Sodium Hydroxide.

6. The fluid composition of any of claims 1-5, further comprising an acidic compound selected from HC1 and Phosphoric acid.

7. A method for increasing production of a hydrocarbon from a well:

injecting a fluid composition into a well wherein the well has been hydraulically fractured with a solution containing water, the fluid composition comprising at least one additive that is able to increase or decrease the pH to be greater than 8.0 or less than 6.0, and a biodiesel product comprising up to 90% methyl esters derived from a plant or an animal;

increasing the pressure of the biodiesel to greater than about 100 psi;

allowing the biodiesel product to remain in the well for greater than 12 hours; pumping an aqueous product from the well.

8. A method for increasing production of a hydrocarbon from a well:

injecting a fluid composition into a well, wherein the well has been hydraulically fractured with a solution containing water, the fluid composition further comprising iodine that creates an exothermic reaction resulting in HI which in turn will decrease the pH to be less than 6.0, wherein the composition further comprises a biodiesel comprising up to 90% methyl esters derived from a plant or an animal;

increasing the pressure of the biodiesel to greater than about 100 psi;

allowing the biodiesel product to remain in the well for greater than 12 hours; pumping the fluid product from the well.

9. The method of claim 8 whereby the exothermic reaction increases the mobility of heavy oils, bitumen, as well as the solvency of the unreacted alpha-pinene dissolves parrafins and waxes thereby improving mobility of the oil.

10. A method of injecting a fluid composition, of any of claims 1-6 into a well bore prior to fracturing/completion of the well and/or after fracturing/completion of the well.