Oil-based drilling fluid compositions comprising layered double hydroxides as rheology modifiers
阅读说明：本技术 包括层状双氢氧化物作为流变改性剂的油基钻井液组合物 (Oil-based drilling fluid compositions comprising layered double hydroxides as rheology modifiers ) 是由 木萨拉特·哈利玛·穆罕默德 休·克里斯托弗·格林威尔 安德鲁·怀廷 马诺哈拉·古蒂约尔·维拉巴 于 2018-08-10 设计创作，主要内容包括：本申请公开了钻井液组合物、用于制备钻井液的方法以及利用所述钻井液钻探地下井的方法。根据一个实施例,钻井液组合物可以包括油相、水相和流变改性剂。所述流变改性剂可以包括层状双氢氧化物,如Mg/Al-肉豆蔻酸根层状双氢氧化物。(Drilling fluid compositions, methods for preparing drilling fluids, and methods of drilling subterranean wells with the drilling fluids are disclosed. According to one embodiment, a drilling fluid composition may include an oil phase, a water phase, and a rheology modifier. The rheology modifier may comprise a layered double hydroxide, such as a Mg/Al-myristate layered double hydroxide.)
1. An oil-based drilling fluid composition comprising:
a base oil in an oil phase;
water in the aqueous phase;
a rheology modifier comprising a layered double hydroxide comprising myristate; and
one or more additives selected from the group consisting of emulsifiers, wetting agents, fluid loss control additives, and weighting additives.
2. The oil-base drilling fluid composition of claim 1 wherein the oil-base drilling fluid comprises the layered double hydroxide comprising the myristate in an amount of 0.1 to 2 wt% based on the total weight of the oil-base drilling fluid.
3. The oil-base drilling fluid composition of any preceding claim wherein the oil-base drilling fluid comprises one or more of:
the base oil in an amount of 10 to 20 wt%, based on the total weight of the oil-based drilling fluid;
one or more wetting agents in an amount of 0.1 to 2 wt%, based on the total weight of the oil-based drilling fluid;
one or more emulsifiers in an amount of 0.1 to 5 weight percent based on the total weight of the oil-based drilling fluid;
one or more fluid loss control additives in an amount of from 0.5 to 2 weight percent based on the total weight of the oil-based drilling fluid; or
One or more weight-increasing additives in an amount of 50 to 90 weight percent based on the total weight of the oil-based drilling fluid.
4. The oil-base drilling fluid composition according to any preceding claim wherein the layered double hydroxide is a Mg/Al-myristate layered double hydroxide.
5. The oil-base drilling fluid composition of any preceding claim wherein the layered double hydroxide comprises one or more of aluminum cations or magnesium cations.
6. A method for preparing an oil-based drilling fluid composition comprising:
mixing a base oil, an aqueous component, and a rheology modifier to form an oil-based drilling fluid composition, wherein:
the oil-based drilling fluid composition comprises an oil phase comprising the base oil and an aqueous phase comprising the water; and is
The rheology modifier comprises a layered double hydroxide comprising myristate.
7. The method of claim 6, further comprising mixing one or more additives selected from the group consisting of emulsifiers, wetting agents, fluid loss control additives, and weighting additives with the base oil, the aqueous component, and the rheology modifier.
8. The method of any of claims 6 or 7, wherein the oil-based drilling fluid comprises one or more of:
the base oil in an amount of 10 to 20 wt%, based on the total weight of the oil-based drilling fluid;
one or more emulsifiers in an amount of 0.1 to 5 weight percent based on the total weight of the oil-based drilling fluid;
one or more wetting agents in an amount of 0.1 to 2 wt%, based on the total weight of the oil-based drilling fluid;
one or more fluid loss control additives in an amount of from 0.5 to 2 weight percent based on the total weight of the oil-based drilling fluid;
one or more weighting additives in an amount of 50 to 90 weight percent based on the total weight of the oil-based drilling fluid; or
The layered double hydroxide is present in an amount of 0.1 to 2 wt.%, based on the total weight of the oil-based drilling fluid.
9. The method of any one of claims 6 to 8, wherein the layered double hydroxide comprises one or more of aluminum cations or magnesium cations.
10. The process according to any one of claims 6 to 9, wherein the layered double hydroxide is a Mg/Al-myristate layered double hydroxide.
11. A method for drilling a subterranean well, the method comprising:
providing an oil-based drilling fluid composition, wherein the oil-based drilling fluid composition comprises:
a base oil in an oil phase;
water in the aqueous phase;
a rheology modifier comprising a layered double hydroxide comprising myristate;
one or more additives selected from the group consisting of emulsifiers, wetting agents, fluid loss control additives, and weighting additives; and
operating a drilling rig in a wellbore in the presence of the oil-based drilling fluid composition.
12. The method of claim 11, wherein the wellbore includes one or more of:
wellbore temperature greater than 300 ° f;
wellbore pressure greater than 10,000 psi; or
The ground temperature is 0 ℃ or less.
13. The method of any of claims 11 or 12, wherein the oil-based drilling fluid comprises one or more of:
the base oil in an amount of 10 to 20 wt%, based on the total weight of the oil-based drilling fluid;
one or more emulsifiers in an amount of 0.1 to 5 weight percent based on the total weight of the oil-based drilling fluid;
one or more wetting agents in an amount of 0.1 to 2 wt%, based on the total weight of the oil-based drilling fluid;
one or more fluid loss control additives in an amount of from 0.5 to 2 weight percent based on the total weight of the oil-based drilling fluid; or
One or more weighting additives in an amount of 50 to 90 weight percent based on the total weight of the oil-based drilling fluid; or
The layered double hydroxide is present in an amount of 0.1 to 2 wt.%, based on the total weight of the oil-based drilling fluid.
14. The method of any one of claims 11 to 13, wherein the layered double hydroxide comprises one or more of an aluminum cation or a magnesium cation.
15. The method of any one of claims 11 to 14, wherein the layered double hydroxide is a Mg/Al-myristate layered double hydroxide.
Technical Field
Embodiments of the present disclosure relate generally to materials and methods for use in natural resource wells, and more particularly, to oil-based drilling fluids for use in high pressure and high temperature drilling operations.
Abbreviations
Throughout this disclosure, the following units of measure or other abbreviated terms are as follows:
degree is equal to degree;
degree centigrade
F ═ degrees Fahrenheit;
percent is percentage;
al ═ aluminum;
cP is centipoises;
ex. ═ example
Fig. fig
g is gram;
h is h;
g ═ storage modulus;
g ═ loss modulus;
HTHP is high temperature, high pressure;
mg is Mg;
m L ═ ml;
MPa ═ MPa;
psi pounds per square inch;
pa · s ═ Pa · s;
s-1the reciprocal of seconds; and
weight percent is weight percent.
Background
For example, drilling operations to drill a new wellbore for hydrocarbon extraction include the conventional practice of continuously circulating a drilling fluid (otherwise known as drilling mud) through the wellbore during the drilling operation. The drilling fluid is pumped into the drill pipe and to the bottom of the borehole where it then flows up through the annular space between the wellbore wall and the drill pipe and finally returns to the surface and flows out of the wellbore where it is recovered for secondary treatment. During drilling, drilling solids (e.g., a portion of a geological formation) may be carried to the surface from at or near the bottom of the wellbore by the drilling fluid. After it is returned to the surface, the drilling fluid may be mechanically or chemically treated to remove captured solids and cuttings from the drilling fluid before being recirculated back through the wellbore.
Disclosure of Invention
In some drilling processes, the drilling fluid experiences a relatively wide variety of environments based on factors such as ambient temperature and physical strain applied to the drilling fluid. For example, the strain exerted on the drilling fluid may vary based on whether the drilling fluid is in circulation or stagnation (e.g., when drilling is stopped). Further, the drilling fluid may experience relatively low temperatures at or near the surface of the wellbore (e.g., near air temperature at the surface), but may experience high pressure, high temperature (HPHT) environmental conditions deeper in the geological formation. As the depth of the wellbore increases, the pressure and temperature at the base of the wellbore also increases. The industry definition of HPHT conditions generally includes wellbore temperatures greater than 300 ° F (149 ℃) and wellbore pressures greater than 10,000psi (68.9 MPa).
Given the circulating nature of the drilling fluid and its function of capturing solids and cuttings during drilling operations, the drilling fluid should flow freely during circulation at a relatively low viscosity to facilitate economical pumping while having sufficient material to retain and transport cuttings and other solids. The drilling fluid should also have sufficient gel strength to suspend solids and cuttings if circulation of the drilling fluid is stopped to prevent solids from accumulating at the bottom of the wellbore. Solids accumulated at the bottom of the wellbore can potentially cause plugging of the drilling rig and physical plugging of the drilling fluid flow path.
However, developing a drilling fluid that can operate in an HPHT environment is challenging. Elevated temperatures may have an adverse effect on some drilling fluids, such that the components cannot withstand elevated temperatures to decompose. Additionally, at elevated temperatures, some drilling fluids may begin to solidify or experience an increase in viscosity, which may impede circulation. Additionally, drilling fluids suitable for HPHT environments may not function properly in non-HPHT environments, such as at temperatures experienced at the surface and low depth portions of a wellbore. At these relatively low temperatures, conventional drilling fluids may have relatively high viscosities both when subjected to relatively small strains (e.g., when drilling and fluid circulation are stopped) and when subjected to relatively large amounts of strain (e.g., when drilling is ongoing and the drilling fluid is circulating).
Accordingly, there is a continuing need for drilling fluids that are thermally stable under HPHT conditions while providing suitable rheological properties at relatively low temperatures, such as those experienced when ground temperatures are relatively low (e.g., at or below 0 ℃, such as in the arctic). For example, desirable drilling fluids (such as those currently described) may have a lower viscosity at a temperature of 0 ℃ (for varying applied shear stress) than some conventional drilling fluids. Thus, the presently described drilling fluids may require less energy to circulate when drilling has stopped, while having acceptable solids retention characteristics. Additionally, at 50 ℃, the presently described drilling fluid may have a greater ability to hold solids when drilling is suspended because it has a greater viscosity at relatively small shear stress rates, while also reducing energy consumption when circulating the drilling fluid because it has a smaller viscosity at relatively large shear stress rates. Without being bound by theory, it is believed that the incorporation of specific rheology modifiers may help to discover the desired rheological properties of the presently disclosed drilling fluids. In particular, the incorporation of layered double hydroxides as rheology modifiers may promote the rheological properties of the drilling fluid, which may be advantageous for drilling in certain environments, such as at or near frozen surface temperatures and in the presence of HPHT environments at the bottom of the wellbore.
In accordance with one or more embodiments, an oil-based drilling fluid composition may include a base oil in an oil phase, water in an aqueous phase, a rheology modifier, and one or more additives selected from the group consisting of emulsifiers, wetting agents, fluid loss control additives, and weighting additives. The rheology modifier may comprise a layered double hydroxide.
According to another embodiment, the oil-based drilling fluid composition may be prepared by a method comprising: the base oil, the aqueous component, and the rheology modifier are mixed to form the oil-based drilling fluid composition. The oil-based drilling fluid composition may comprise an oil phase comprising a base oil and an aqueous phase comprising water. The rheology modifier may comprise a layered double hydroxide.
According to yet another embodiment, a subterranean well can be drilled by a method comprising: the method includes providing an oil-based drilling fluid composition, and operating a drilling rig in a wellbore in the presence of the oil-based drilling fluid composition. The oil based drilling fluid composition may comprise a base oil in an oil phase, water in an aqueous phase, a rheology modifier, an emulsifier and one or more additives selected from wetting agents, fluid loss control additives and weighting additives. The rheology modifier may comprise a layered double hydroxide. The emulsifier may comprise a compound having the formula R-CO-NH-R' -NH2Wherein R is a fatty acid alkyl group, R' is an alkyl group, and R "is an alkyl group.
Additional features and advantages of the described embodiments will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the described embodiments, including the detailed description which follows and the claims.
Drawings
The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings.
FIG. 1 is a graph depicting viscosity as a function of shear rate for various drilling fluids tested at 0 ℃ and 50 ℃, in accordance with one or more embodiments of the present disclosure.
FIG. 2 is a graph depicting storage modulus (G ') and loss modulus (G') of various drilling fluids tested at 50 ℃ as a function of percent strain, in accordance with one or more embodiments of the present disclosure.
FIG. 3 is a graph depicting storage modulus (G ') and loss modulus (G') of various drilling fluids tested at 50 ℃ as a function of percent strain, in accordance with one or more embodiments of the present disclosure.
FIG. 4 is a graph depicting storage modulus (G ') and loss modulus (G') of various drilling fluids tested at 50 ℃ as a function of percent strain, in accordance with one or more embodiments of the present disclosure.
Fig. 5 provides a graph of phase angle as a function of percent strain for various drilling fluids tested at 50 ℃ in accordance with one or more embodiments of the present disclosure.
Detailed Description
Embodiments of the present disclosure relate to emulsifiers for oil-based drilling fluids, and additionally to oil-based drilling fluid compositions incorporating the disclosed rheology modifiers. Oil-based drilling fluids are a combination of a continuous oil phase, an aqueous phase, and at least one rheology modifier. The rheology modifier may comprise a layered double hydroxide, such as a Mg/Al-myristate layered double hydroxide.
To drill a subterranean well, a drill string including a drill bit and drill collars weighting the drill bit is inserted into a pre-drilled hole and rotated to cut the drill bit into the rock at the bottom of the hole. Drilling operations produce cuttings. To remove cuttings from the bottom of the wellbore, a drilling fluid, such as a drilling fluid composition, is pumped down the drill string to the drill bit. The drilling fluid cools the drill bit, provides lubrication, and lifts debris, known as drill cuttings, off the drill bit. The drilling fluid carries the cuttings up as it is recirculated back to the surface. At the surface, the drill cuttings are removed from the drilling fluid by secondary operations, and the drilling fluid may be recirculated down the drill string to the bottom of the wellbore for collection of additional drill cuttings. Those skilled in the art will appreciate that a number of terms familiar to those skilled in the art may be used to describe the same. For example, a subterranean well can alternatively be referred to as a well or a wellbore, and the use of a single term is also intended to encompass each related term.
Drilling fluids include drilling muds, packer fluids, suspensions (subspension fluids) and completion fluids. In general, drilling fluids provide a number of functions, with different types dedicated to specific functions. In one or more embodiments, the oil-based drilling fluid composition suspends the drill cuttings and the weighting material transports the drill cuttings to the wellbore surface along with the oil-based drilling fluid composition. Additionally, the oil-based drilling fluid composition may absorb gas, such as carbon dioxide (CO), in the wellbore2) Hydrogen sulfide (H)2S) and methane (CH)4) And transport them to the wellbore surface for release, sequestration, or burn-off. The oil-based drilling fluid composition may additionally provide buoyancy to the drill string, relieving drag on the drill string as the length of the wellbore increases. In one or more embodiments, the oil-based drilling fluid composition also provides cooling and lubricating functions for cooling and lubricating drill bits and drill strings used in drilling operations. In other embodiments, the oil-based drilling fluid composition also controls the subterranean pressure. In particular, the oil-based drilling fluid composition can provide hydrostatic pressure in the wellbore to provide support to the sidewall of the wellbore and prevent the sidewall from collapsing and collapsing on the drill string. Additionally, the oil-based drilling fluid composition may provide hydrostatic pressure in the borehole to prevent fluids in the downhole formation from flowing into the wellbore during drilling operations.
Under certain extreme downhole conditions, such as over-temperature or difficult formations, some properties of the drilling fluid may change. For example, interaction of the drilling fluid with a formation having swelling or dispersible clays, or both, or subjecting the drilling fluid to extreme downhole temperatures may result in thickening or thinning of the drilling fluid, excessive increases or decreases in viscosity, or any combination of these. For example, drilling fluids used in High Pressure and High Temperature (HPHT) operations may experience wellbore temperatures greater than 300 ° f (about 149 ℃) and wellbore pressures greater than 10,000psi (about 68.9MPa), which is the industry definition of HPHT conditions. Under HPHT conditions, conventional drilling fluids may decompose or undergo undesirable changes in rheology. In further embodiments, the presently disclosed drilling fluids may desirably operate even under undesirable downhole conditions, such as gas influx, which may dilute or chemically destabilize the drilling fluid, or evaporant formation, which may destabilize the drilling fluid.
Embodiments of the oil-based drilling fluid compositions are formulated to provide improved rheology. In particular, the oil-based drilling fluid composition may be formulated to have a similar or greater viscosity at low shear rates as compared to conventional HPHT oil-based drilling fluids, a lesser or similar viscosity at high shear rates as compared to conventional HPHT oil-based drilling fluids, or both. The greater viscosity at low shear rates allows the oil-based drilling fluid composition to effectively retain drill cuttings when drilling operations are stopped. Conversely, a lower viscosity at high shear rates requires less power to circulate the oil-based drilling fluid composition during drilling operations. As presently described, a low shear rate may be described as, for example, less than or equal to 10 seconds-1And a high shear rate can describe, for example, greater than or equal to 100 seconds-1The shear rate of (c).
In one or more embodiments, the drilling fluid includes an oil phase that includes a base oil. The oil phase of the oil-based drilling fluid may include synthetic oil or natural petroleum products as base oil. Natural petroleum derived products may include oils such as diesel or mineral oils. Synthetic oils may contain esters or olefins. In addition, the synthetic oil or natural petroleum product may be composed of hydrocarbons such as normal paraffins, iso-paraffins, cyclic paraffins, branched paraffins, or mixtures thereof. For example, the base oil may comprise C8 to C26 straight or branched chain saturated alkyl hydrocarbons, as found in Saraline 185V, commercially available from Shell company (Shell). Additional base oils may include, but are not limited to, DF-1 and EDC 99-DW from Doudal (Total) and Escaid110 from Exxon Mobil. Additional suitable base oils may include one or more of mineral oil, paraffin, or diesel. In various embodiments, the oil-based drilling fluid composition may include 5 to 45 wt%, such as 5 to 30 wt%, 5 to 20 wt%, 5 to 15 wt%, 5 to 10 wt%, 10 to 45 wt%, 15 to 45 wt%, 20 to 45 wt%, 30 to 45 wt%, 5 to 25 wt%, or 10 to 20 wt% base oil, based on the total weight of the oil-based drilling fluid composition.
The water phase of the oil-based drilling fluid may include water and a salt source. In one or more embodiments, the water includes one or more of: deionized water, tap water, distilled water or fresh water; natural, semi-brackish and saturated brines; natural, salt domes, produced hydrocarbon formations or synthetic brines; filtered or untreated seawater; mineral water; and other drinking and non-drinking water containing one or more dissolved salts, minerals or organic substances. In some embodiments, the aqueous phase may comprise, for example, brine comprised of water and a salt selected from one or more of calcium chloride, calcium bromide, sodium chloride, sodium bromide, and combinations thereof. The oil-based drilling fluid may contain from 2 wt% to 10 wt% of the aqueous phase, based on the total weight of the oil-based drilling fluid. In various embodiments, the oil-based drilling fluid composition may have from 2 wt% to 12 wt%, such as from 4 wt% to 10 wt%, from 2 wt% to 8 wt%, from 2 wt% to 6 wt%, from 2 wt% to 5 wt%, from 3 wt% to 10 wt%, from 3 wt% to 8 wt%, from 3 wt% to 6 wt%, from 4 wt% to 10 wt%, from 4 wt% to 8 wt%, from 4 wt% to 6 wt%, or from 4 wt% to 5 wt% aqueous phase, based on the total weight of the oil-based drilling fluid composition. In some embodiments, the oil-based drilling fluid may have a volume to oil ratio of, for example, 50:50 to 95:5, 75:20 to 95:5, 85:15 to 95:5, or 90:10 to 95: 5. The oil-to-water ratio of the oil-based drilling fluid composition is the volume ratio calculated as the oil: water ═ base oil + (one or more) surfactants + (one or more) emulsifiers + (one or more) wetting agents + oil portion of layered double hydroxide: water + water portion of brine. By way of example and not limitation, where the brine may be X% water by volume, X% of the brine volume is included as the water volume.
In an embodiment, the oil-based drilling fluid composition comprises a rheology modifier. For example, the rheology modifier may be a viscosifier to impart non-newtonian fluid rheology to the oil based drilling fluid composition to facilitate lifting and transferring the rock cuttings to the surface of the wellbore. In one or more embodiments, the oil-based drilling fluid may include a layered double hydroxide, such as a Mg/Al-myristate layered double hydroxide, as a rheology modifier. As used in this disclosure, layered double hydroxide refers to a layered double hydroxide having the general layer sequence [ ACBZADB]nAccording to one or more embodiments, the C and D layers may include different metal cations, for example, the C layer may include a magnesium cation, such as a divalent magnesium cation, and the D layer may include an aluminum cation, such as a trivalent aluminum cation3)(CH2)12COOH, and the myristate ion included in the layered double hydroxide may have the general formula (CH)3)(CH2)12COO-is provided. According to one or more embodiments, the layered double hydroxide has the formula:
[C1-xDx(OH)2]Y+(OOC(CH2)12CH3)Y-
wherein x is from 0.1 to 0.33 and Y represents the ionic charge of the metal cation and the myristate anion.
According to one or more embodiments, the layered double hydroxide may be prepared by a process comprising: the cationic salt and the myristate salt are mixed in water, and the mixture is then subjected to hydrothermal treatment at elevated temperature such as at least 100 ℃, at least 125 ℃, or even at 150 ℃ or higher (e.g., 100 ℃ to 200 ℃) for a period of 4 hours to one week, such as 6 hours to 48 hours. After the reaction by hydrothermal treatment, the double-layered hydroxide may be separated from other substances by dispersing the reaction product in a solvent (e.g., acetone), and optionally stirring at room temperature for at least 1 minute (e.g., for a period of 15 minutes to 45 minutes). After acetone treatment, the double layer hydroxide can be recovered by heating to high temperature in an oven and then washing with hot water.
In one or more embodiments, the double layer hydroxide may comprise magnesium and aluminum, and the molar ratio of magnesium to aluminum may be from 0.5 to 10, such as from 1 to 5. In additional embodiments, the molar ratio of myristate to total metal cations can be 1 to 3, such as 1 to 2 or 1.5. According to one or more embodiments, the use of Mg (NO) can be used3)2·6H2O、Al(NO3)3·9H2Precursor materials of O, urea and sodium myristate.
In some embodiments, the oil-based drilling fluid composition may optionally include an organophilic hectorite clay, such as SAGE L HT from MI-SWACO (MI-SWACO, Houston, VERTX) of Houston, Kxas, or an organophilic clay, such as Elements Specialties, available from Elements Specialties, Inc. of Highstown, NJ, N.J.42。
Exemplary oil-based drilling fluid compositions may include 0.1 wt% to 2 wt% of a rheology modifier, based on the total weight of the oil-based drilling fluid composition. In some embodiments, the oil-based drilling fluid composition may include 0.1 wt% to 1 wt% of a layered double hydroxide, such as a Mg/Al-myristate layered double hydroxide. For example, at least 0.1 wt.%, at least 0.3 wt.%, at least 0.5 wt.%, at least 0.7 wt.%, or at least 0.8 wt.% of the oil-based drilling fluid may be a rheology modifier.
The oil-based drilling fluid composition further comprises one or more additives. Exemplary additives include, but are not limited to, emulsifiers, wetting agents, fluid loss control additives, and weighting additives. The oil-based drilling fluid composition may also optionally include alkalinity modifiers, electrolytes, glycols, glycerin, dispersion aids, corrosion inhibitors, defoamers, and other additives or combinations of additives.
Suitable emulsifiers may include fatty acids, invert emulsifiers, and oil wetting agents for synthetic-based drilling fluid systems, such as L ESUPERMU L, commercially available from Halliburton Energy Services, IncTMAnd MU L XT L E SUPERMU L, commercially available from M-I SWACOTMIs a carboxylic acid terminated polyamide.
In one or more embodiments, the total amount of emulsifier in the drilling fluid composition may be 0.05 wt% to 5 wt%, 0.1 wt% to 2.5 wt%, 0.1 wt% to 1.5 wt%, 0.1 wt% to 1 wt%, 0.5 wt% to 2.5 wt%, 0.5 wt% to 2 wt%, 0.5 wt% to 1.5 wt%, 0.5 wt% to 1 wt%, 0.75 wt% to 2.5 wt%, 0.75 wt% to 2 wt%, 0.75 wt% to 1.5 wt%, 0.75 wt% to 1 wt%, 0.8 wt% to 1.1 wt%, 0.8 wt% to 1 wt%, or 0.9 wt% to 1.1 wt%, based on the total weight of the drilling fluid composition.
In embodiments, the oil-based drilling fluid composition may include a weight gain additive to increase the weight, density, or both of the oil-based drilling fluid. The weighting additives may be used to control formation pressure and help resist the effects of collapsed or swollen shale that may be encountered in stressed areas. Any material that is denser than water and does not adversely affect other properties of the drilling fluid may be used as the weight material. In some embodiments, the weight material may be a particulate solid having a Specific Gravity (SG) sufficient to increase the density of the drilling fluid composition by an amount without adding excess weight material such that the drilling fluid composition cannot circulate through the wellbore. The weight material may have a Specific Gravity (SG) of 2 grams per cubic centimeter (g/cm)3) To 6g/cm3. Examples of the weight regulator or the density regulator include barite (BaSO)4) Galena (PbS), hematite (Fe)2O3) Magnetite (Fe)3O4) Artificial iron oxide, ilmenite (FeO. TiO)2) Siderite (FeCO)3) Celestite (SrSO)4) Dolomite (CaCO)3·MgCO3) And calcite (CaCO)3)。
The oil-based drilling fluid composition may include an amount of weight material sufficient to increase the density of the drilling fluid composition to allow the drilling fluid composition to prop up the wellbore and prevent fluids in the downhole formation from flowing into the wellbore. In embodiments, the oil-based drilling fluid composition may include 1 wt% to 80 wt% weight material, based on the total weight of the oil-based drilling fluid composition. In some embodiments, the oil-based drilling fluid composition may include 1 to 90 wt.%, 20 to 80 wt.%, 20 to 75 wt.%, 50 to 80 wt.%, 50 to 75 wt.%, 60 to 80 wt.%, 60 to 75 wt.%, 65 to 80 wt.%, or 70 to 80 wt.% weight gain additive, based on the total weight of the oil-based drilling fluid composition. In some embodiments, the oil-based drilling fluid composition may include 50 to 90 weight percent weight gain additive based on the total weight of the oil-based drilling fluid composition.
The oil-based drilling fluid composition may beOptionally including at least one alkalinity adjusting agent. In embodiments, the oil-based drilling fluid composition may optionally include at least one alkaline compound to adjust the pH of the oil-based drilling fluid composition. Examples of alkaline compounds may include, but are not limited to, lime (calcium hydroxide or calcium oxide), soda ash (sodium carbonate), sodium hydroxide, potassium hydroxide, other strong bases, or combinations of these alkaline compounds. It should be noted that pKaConjugate bases of acids greater than about 13 are considered strong bases. The basic compound may be in contact with a gas (e.g., CO) encountered by the drilling fluid composition during drilling operations2Or H2S) to prevent the gas from hydrolyzing the components of the water-based drilling fluid composition. Some exemplary water-based drilling fluid compositions may optionally include 0.1 wt% to 3 wt%, 0.4 wt% to 2 wt%, or 0.6 wt% to 0.8 wt% lime.
In one or more embodiments, surfactants such as wetting agents may be added to enhance the stability of the suspension or emulsion in the oil based drilling fluid composition. Suitable wetting agents may include fatty acids, organic phosphates, modified imidazolines, amidoamines, alkyl aromatic sulfates, and sulfonates. For example,M-I SWACO, commercially available from Houston, Tex, is an oil-based wetting agent and secondary emulsifier that can be used to wet fines and drill cuttings to prevent water-wet solids. In addition to this, the present invention is,thermal stability, rheological stability, filtration control, emulsion stability of the wellbore fluid can be improved.It is commercially available from M-I ltd, houston, texas, as another wetting agent, and is particularly effective in making hematite systems difficult to wet. Exemplary oil-based drilling fluid compositions may optionally include 0.1 wt.% to 2 wt.% of a wetting agent, based on the total weight of the oil-based drilling fluid composition. In some casesIn embodiments, the oil-based drilling fluid composition may optionally include 0.25 wt% to 0.75 wt%, based on the total weight of the oil-based drilling fluid compositionEach of the above. Other suitable wetting agents may optionally be included in the oil-based drilling fluid composition without departing from the scope of the present subject matter.
In one or more embodiments, fluid loss control agents may be added to the oil-based drilling fluid composition to reduce the amount of filtrate lost from the oil-based drilling fluid composition into the subterranean formation examples of fluid loss control agents include organophilic (e.g., amine-treated) lignite, bentonite, manufactured polymers, and diluents or antiflocculants when used, they may comprise from 0.5 wt% to 3 wt% of the oil-based drilling fluid composition based on the total weight of the drilling fluid, in various embodiments, the fluid loss control agent may comprise from 0.5 wt% to 1.5 wt%, from 0.5 wt% to 1.25 wt%, from 0.75 wt% to 2 wt%, from 0.75 wt% to 1.5 wt%, from 0.75 wt% to 1.25 wt%, from 1 wt% to 2 wt%, from 1 wt% to 1.5 wt%, or from 1 wt% to 1.25 wt% of the oil-based on the total weight of the drilling fluid compositionTM、VERSALIGTM、ECOTROLTMRD、ONETROLTMHT, EMI 789 and NOVATECHTMF, all of which are commercially available from MI SWACO of Houston, Tex, andcommercially available from Hardbergon energy service, in some embodiments, the oil-based drilling fluid composition may optionally include ONETRO L at a weight ratio of about 10:1, respectivelyTMHT and ECOTRO LTMRD, both.
Optional suspending agents may be added to the oil based drilling fluid composition to adjust the viscosity of the oil based drilling fluid composition to have a yield point sufficient to suspend all drilling fluid components at low shear rates, whereby settling of the components of the oil based drilling fluid composition may be avoided. Examples of suspending agents include fatty acids and fibrous materials. When suspending agents are used, they may comprise from 0.0 wt% to 1.0 wt% or from 0.01 to 0.5 wt% of the oil-based drilling fluid composition, based on the total weight of the drilling fluid.
In accordance with one or more embodiments, to maintain solids and cuttings suspended in the oil-based drilling fluid composition during low speed drilling or between drilling operations, a viscosity above a threshold value at a lower shear rate is advantageous. In one or more embodiments, at 10.22 seconds-1The viscosity of the oil-based drilling fluid measured at 50 ℃ or 0 ℃ at atmospheric pressure is at least 358cP, at least 1000cP, or even at least 1850cP at the shear rate of (a).
In accordance with one or more embodiments, to allow the oil-based drilling fluid composition to circulate without the need for excessive energy, it is advantageous at higher shear rates during viscosities below a threshold value. In one or more embodiments, at 170 seconds-1The viscosity of the oil-based drilling fluid measured at 50 ℃ or 0 ℃ at atmospheric pressure is less than or equal to 222cP, less than or equal to 175cP, or even less than or equal to 128 cP.
Having previously described oil-based drilling fluid compositions according to various embodiments, an illustrative method for preparing an oil-based drilling fluid composition will now be described. A method for preparing an oil-based drilling fluid may include mixing a base oil, at least one emulsifier, and at least one wetting agent to form a first mixture. The ingredients of the first mixture may be added to provide the amounts previously described with respect to the examples of oil-based drilling fluid compositions. The method for preparing an oil-based drilling fluid composition may optionally include mixing at least one rheology modifier and an alkalinity modifier into the first mixture to form a second mixture. Likewise, the ingredients of the second mixture may be added to provide the amounts previously described with respect to the examples of oil-based drilling fluid compositions. The method for preparing an oil-based drilling fluid composition may optionally include mixing at least one fluid loss control additive into the second mixture to form a third mixture. Likewise, the ingredients of the third mixture may be added to provide the amounts previously described with respect to the examples of oil-based drilling fluid compositions. The method for preparing an oil-based drilling fluid composition may further comprise mixing a brine solution into the first mixture or the third mixture to form a fourth mixture. The ingredients of the fourth mixture may be added to provide the amounts previously described with respect to the examples of oil-based drilling fluid compositions. The method for preparing an oil-based drilling fluid composition may further comprise mixing a weight gain additive into the fourth mixture to form the oil-based drilling fluid composition. The components of the oil-based drilling fluid composition may be added to provide the amounts previously described with respect to the examples of oil-based drilling fluid compositions.
The previously described oil-based drilling fluid compositions may be well suited for use in drilling operations for subterranean formations, particularly for drilling operations conducted under HPHT conditions where the wellbore pressure is greater than 10,000psi and the wellbore temperature is greater than 300 ° f (149 ℃). Accordingly, embodiments of a method for drilling a well in a subterranean well under high pressure, high temperature conditions may include providing an oil-based drilling fluid composition according to any of the embodiments described herein. A method for drilling a well in a subterranean well under high pressure and temperature conditions comprises operating a drilling rig in a wellbore in the presence of an oil-based drilling fluid composition.
Examples of the invention
The following examples illustrate one or more additional features of the present disclosure. It should be understood that these examples are not intended to limit the scope of the present disclosure or appended claims in any way.
Preparing Mg/Al-myristate layered double hydroxide. As starting material, Mg (NO)3)2·6H2O、Al(NO3)3·9H2O, urea and sodium myristate were purchased from Sigma Aldrich (Sigma Aldrich) and used without further purification. In the whole synthesis process, the catalyst is prepared byPurifying purified water treated by the water purification system and decarbonizing the water by heating at 75 deg.C to avoid any CO2And (4) pollution. To form the layered double hydroxide, 11.596g of Mg (I: (I))NO3)2·6H2O, 8.35g of Al (NO)3)3·9H2O and 12.16g of urea were placed in a 1000m L autoclave lined with Teflon (Teflon) at a Mg/Al molar ratio of 2 and a urea to metal molar ratio of 3. to this mixture 25.34g of sodium myristate and 500m L of hot decarbonated water were added to form a mixture with a myristate/metal molar ratio of 1.5. the resulting reaction mixture was hydrothermally treated at 150 ℃ for 24 hours after the reaction, the whole product was dispersed in acetone and stirred at room temperature for 30 minutes.
In order to compare the physical and rheological properties of drilling fluids containing Mg/Al-myristate layered double hydroxide rheology modifier with those of drilling fluids containing industry standard viscosity modifiers, four drilling fluids were prepared. The four drilling fluids are based on M-I SWACO RHADIANTTMSpecifically, VERSAGE L HT and Bentone42 were used as rheology modifiers to prepare comparative drilling fluids, comparative example A. other drilling fluids (examples 1-3) were prepared by replacing VERSAGE L HT, Bentone42, or both with Mg/Al-myristate layered double hydroxide.
Comparative example a and examples 1-3 drilling fluids were formulated using the following ingredients: saraline 185V, a synthetic oil drilling base fluid, available from shell company;an amino amine surfactant, available from M-I SWACO Inc. (Houston, Tex., USA);a wetting agent available from M-I SWACO Inc. (Houston, Tex., USA), MU L XT, an emulsifier for non-aqueous fluid systems available from M-I SWACO Inc. (Houston, Tex., USA), VERSAGE L HT, a hectorite clay tackifier to aid in filtration control available from M-I SWACO Inc. (Houston, Tex., USA), Bentone42, a hectorite organoclay tackifier available from Elementis Specialties Inc. (Elementis Specialties, Inc.) (east Windsa, N.J.), (ONE-TRO L)TMHT, an amine treated tannin filtration control additive designed for use in oil and synthetic base drilling fluid systems, available from M-I SWACO Inc. (Houston, Tex., USA), ECOTRO L RD, a filtration control additive designed for use in oil and synthetic base drilling fluid systems, available from M-I SWACO Inc. (Houston, Tex., USA), and barite (BaSO)4) Weighting agents, available from M-I SWACO Inc. (Houston, Tex., USA). Further, lime having a specific gravity of 2.24 at 20 ℃ and a bulk density of 400kg/m was used3(ii) a CaCl from Schlumberger2Brine; and fresh water are included.
30.88g, 25.98g, 25.665g and 25.740g of comparative example A and example 1-3 drilling fluids, respectively, were prepared using a magnetic stir bar, the formulation of comparative example A and example 1 drilling fluids is provided in Table 1. to prepare the drilling fluids, base oil, emulsifier and wetting agent were first mixed together for 10 minutes during phase 1. then during phase 2, viscosity modifier and rheology modifier were added and mixed for an additional 20 minutes. specifically, Mg/Al-myristate D L H was used in examples 1-3, but not in comparative example A. next, in phase 3, fluid loss control additives were added and mixed for 20 minutes, followed by brine and fresh water in phase 4, and heavy spar in phase 5, which were mixed for 30 minutes and 40 minutes, respectively.
Table 1: formulation and mixing procedure for HPHT oil-based drilling fluids
After 17 hours of mixing, the comparative example a and examples 1-3 drilling fluids were allowed to stand and then checked for sag and fluid separation prior to rheological measurements. Fluid separation and sagging were visually inspected. Specifically, visual separation of solids and liquids was examined. Sag can also be checked by inserting micro-blades into the mud to check if the mud is similar in texture from top to bottom (subjectively hard or soft) and if there is separation and settling of solids so that the solids are no longer evenly distributed throughout the drilling fluid. If there is sag (as evidenced by separation and settling of solids) then the mud will appear softer at the top and harder at the bottom of the vessel in which the drilling fluid is resting. As described, sag refers to when solids settle with increased density, such as when heavier materials such as barite move to the bottom and vigorous mixing may be required to disperse the solids back into solution. Fluid separation means that the fluid is separated at the top, but the content of the components remains dispersed, while no heavy solids are separated from the rest of the components and settle at the bottom.
The viscosity of the drilling fluids was tested using a stress and strain controlled Rheometer (Discover Hybrid Rheometer from TA instruments, New Castle, DE) from nocauser, tera. The geometry used in the rheometer was 25mm rough stainless steel parallel plates. This geometry was chosen because of the presence of particulate barite in the sample. The gap between the stainless steel plates was set to 300 μm. From 0.004 to 2000 seconds at 0 ℃ and 50 ℃ under atmospheric pressure-1The viscosity measurements were performed as a function of shear rate. When no force is applied, compareExample a and examples 1-3 the drilling fluids gelled and were strong enough to hold drilling solids and weighting materials such as barite. In addition, shear rate experiments provide useful fluid viscosity information and whether the fluid has zero shear or shear thinning. Shear rate experiments also indicate the shear rate at which the drilling fluid deforms.
Figure 1 depicts the viscosity of the test samples as a function of shear rate at 0 ℃ and 50 ℃. In addition, selected results from the results of rheological measurements shown in fig. 1 tested at 50 ℃ are included in table 2.
Table 2: rheology of HPHT oil-based drilling fluids
Referring to fig. 1 and table 2, both comparative example a and example 1 exhibited shear thinning behavior regardless of their formulations and test temperatures. However, examples 1-3 had relatively low shear rates (e.g., 10.22 seconds) at 50 ℃ compared to comparative example A at the same temperature and shear rate-1) The fluids of examples 1-3 were allowed to retain solids at rest at 50 ℃ at least as good as the comparative example a fluid. Additionally, the drilling fluids of examples 1-3 had viscosities less than or equal to the drilling fluid of comparative example A at 50 ℃. Thus, the examples 1-3 drilling fluids may require less energy to circulate at 50 ℃. The rheological properties at 50 ℃ of examples 1-3 and comparative example a show that example 1 retains solids better at rest due to the higher viscosity at low shear rates when compared to comparative example a, while exhibiting less power requirements during drilling fluid circulation due to the lower viscosity at high shear rates.
As shown in FIGS. 1-3 and Table 2, the drilling fluids of examples 1-3 were at 0 ℃ for 10.22 seconds as compared to the drilling fluid of comparative example A-1Has a lower viscosity and is 170 seconds at 0 ℃ compared to the comparative example A drilling fluid-1The lower also has a lower viscosity. Thus, although the drilling fluids of examples 1-3 had a slightly lower gel strength during the stagnation period of drilling than comparative example A, the circulation of the drilling fluids of examples 1-3 at 0℃ would requireLess energy is required. Thus, the example 1-3 drilling fluids may be superior to the comparative example a drilling fluid at 0 ℃, as long as the viscosity of the example 1-3 drilling fluids is acceptable for retaining solids during periods of stagnation.
The example 1 drilling fluids exhibit the characteristic of a brittle gel such that they gel upon stress relief. This is related to the drilling fluid, which will gel once drilling is stopped, so that the drilling fluid will effectively support the cuttings.
Table 3: oil-based drilling fluids: % strain and separation
Neither example 1 nor comparative example a showed sagging and showed only traces or some separation after 17 hours of standing after preparation. At 50 ℃, example 1 deforms at a lower strain than comparative example a, as shown in table 3. Thus, the drilling fluids of examples 1-3 would require less power to initiate drilling. Trace separation was observed when only a thin layer of liquid was observed from the top of the vessel. Some separation was observed when a thin layer of liquid was visible at the top of the container and the sides of the container.
In fig. 2, the storage modulus (G') and loss modulus (G ") at 50 ℃ are depicted as a function of% strain. In addition, the phase angle at 50 ℃ as a function of% strain is depicted in fig. 3. The storage modulus (G') of the drilling fluids of examples 1-3 were all greater than the loss modulus (G "), indicating that all of the drilling fluids had solid-like properties similar to the drilling fluid of comparative example A. The storage modulus (G ') and loss modulus (G ") values of the drilling fluids of examples 1-3 are similar to or greater than the G' and G" values of comparative example a, but they deform at lower strain and therefore require less power to start the cycle and less power during the cycle than comparative example a drilling fluids. The example 1-3 drilling fluids become more liquid (G "> G') at lower% strain at 50 ℃ compared to the comparative drilling fluids, and therefore also require less power during circulation. The phase angle of the drilling fluids of examples 1-3 began to behave like a semi-solid at lower strains than comparative example 1.
It should be understood that any two quantitative values assigned to a property may constitute a range for that property, and all combinations of ranges formed from all of the quantitative values for a given property are contemplated in this disclosure. It is understood that in some embodiments, the compositional range of a chemical component in a composition or formulation should be understood to contain a mixture of isomers of the component. It is to be understood that the examples provide compositional ranges for the various compositions, and that the total amount of isomers for a particular chemical composition can constitute a range.
It is noted that one or more of the following claims use the term "wherein" as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open transition phrase that is used to introduce a recitation of a series of features of structure and is to be interpreted in a manner similar to the more commonly used open-ended introductory term "comprising".
It should be understood that any two quantitative values assigned to a property may constitute a range for that property, and all combinations of ranges formed from all of the quantitative values for a given property are contemplated in this disclosure.
It should be apparent to those skilled in the art that various modifications to the described embodiments can be made without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the present specification cover the modifications and variations of the various described embodiments provided such modifications and variations are within the scope of the appended claims and their equivalents.
The presently described subject matter may include one or more aspects that should not be viewed as limiting the teachings of this disclosure. A first aspect may include an oil-based drilling fluid composition comprising: a base oil in an oil phase; water in the aqueous phase; a rheology modifier comprising a layered double hydroxide comprising myristate; and one or more additives selected from the group consisting of emulsifiers, wetting agents, fluid loss control additives, and weighting additives.
A second aspect may include a method for preparing an oil-based drilling fluid composition comprising: mixing a base oil, an aqueous component, and a rheology modifier to form an oil-based drilling fluid composition, wherein: the oil-based drilling fluid composition comprises an oil phase comprising a base oil and an aqueous phase comprising water; and the rheology modifier comprises a layered double hydroxide comprising myristate.
A third aspect may include a method for drilling a subterranean well, the method comprising: providing an oil-based drilling fluid composition, wherein the oil-based drilling fluid composition comprises: a base oil in an oil phase; water in the aqueous phase; a rheology modifier comprising a layered double hydroxide comprising myristate; one or more additives selected from the group consisting of emulsifiers, wetting agents, fluid loss control additives, and weighting additives; and operating the drilling rig in the wellbore in the presence of the oil-based drilling fluid composition.
Another aspect includes any of the preceding aspects, wherein the oil-based drilling fluid comprises a layered double hydroxide comprising myristate in an amount of 0.1 wt% to 2 wt% based on the total weight of the oil-based drilling fluid.
Another aspect includes any of the preceding aspects, wherein the oil-based drilling fluid comprises a base oil in an amount of 10 wt% to 20 wt%, based on the total weight of the oil-based drilling fluid.
Another aspect includes any of the preceding aspects, wherein the oil-based drilling fluid comprises one or more wetting agents in an amount of 0.1 wt% to 2 wt%, based on the total weight of the oil-based drilling fluid.
Another aspect includes any of the preceding aspects, wherein the oil-based drilling fluid comprises one or more emulsifiers in an amount from 0.1 wt% to 5 wt%, based on the total weight of the oil-based drilling fluid.
Another aspect includes any of the preceding aspects, wherein the oil-based drilling fluid comprises one or more fluid loss control additives in an amount of 0.5 wt% to 2 wt%, based on the total weight of the oil-based drilling fluid.
Another aspect includes any of the preceding aspects, wherein the oil-based drilling fluid comprises one or more weight-increasing additives in an amount of 50 wt% to 90 wt%, based on the total weight of the oil-based drilling fluid.
Another aspect includes any of the preceding aspects, wherein the layered double hydroxide is a Mg/Al-myristate layered double hydroxide.
Another aspect includes any of the preceding aspects, wherein the layered double hydroxide comprises an aluminum cation.
Another aspect includes any of the preceding aspects, wherein the layered double hydroxide comprises magnesium cations.
Another aspect includes any of the preceding aspects, wherein the layered double hydroxide is a Mg/Al-myristate layered double hydroxide, and wherein the oil-based drilling fluid comprises the layered double hydroxide in an amount of 0.1 wt% to 2 wt% based on the total weight of the oil-based drilling fluid.
Another aspect includes any of the preceding aspects, further comprising mixing one or more additives selected from the group consisting of emulsifiers, wetting agents, fluid loss control additives, and weighting additives with the base oil, the aqueous component, and the rheology modifier.
Another aspect includes any of the preceding aspects, wherein the wellbore contains a wellbore temperature greater than 300 ° f.
Another aspect includes any of the preceding aspects, wherein the wellbore contains a wellbore pressure greater than 10,000 psi.
Another aspect includes any of the preceding aspects, wherein the ground temperature is 0 ℃ or less.
The subject matter of the present disclosure has been described in detail and with reference to specific embodiments, but it should be noted that various details described in the present disclosure should not be understood as implying that such details relate to elements that are essential components of the various embodiments described in the present disclosure, even if specific elements are shown in each of the figures accompanying this specification. Rather, the following claims should be looked to in order to indicate the only indication of the breadth of the disclosure and corresponding scope of the various embodiments described in the disclosure. In addition, it will be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the present specification cover the modifications and variations of the various described embodiments provided such modifications and variations are within the scope of the appended claims and their equivalents.