EP1571078A1 - Brine-based drilling fluids for ballast tank storage - Google Patents

Brine-based drilling fluids for ballast tank storage Download PDF

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Publication number
EP1571078A1
EP1571078A1 EP05075864A EP05075864A EP1571078A1 EP 1571078 A1 EP1571078 A1 EP 1571078A1 EP 05075864 A EP05075864 A EP 05075864A EP 05075864 A EP05075864 A EP 05075864A EP 1571078 A1 EP1571078 A1 EP 1571078A1
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EP
European Patent Office
Prior art keywords
drilling
drilling fluid
fluid
ballast tank
vessel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05075864A
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German (de)
French (fr)
Inventor
Charles Boatman
Brent Estes
Leonard Morales
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Halliburton Energy Services Inc
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Halliburton Energy Services Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US09/294,758 external-priority patent/US6315061B1/en
Application filed by Halliburton Energy Services Inc filed Critical Halliburton Energy Services Inc
Publication of EP1571078A1 publication Critical patent/EP1571078A1/en
Withdrawn legal-status Critical Current

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Classifications

    • EFIXED CONSTRUCTIONS
    • E21EARTH OR ROCK DRILLING; MINING
    • E21BEARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B21/00Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
    • E21B21/001Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor specially adapted for underwater drilling
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B63SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63BSHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B63B35/4413Floating drilling platforms, e.g. carrying water-oil separating devices

Definitions

  • the present invention relates in general to a brine-based drilling fluid and methods for storing fluids on drilling vessels, and more specifically to storing brine-based drilling fluids in drilling vessel ballast tanks.
  • Sub-sea geologic sediments and structures are often similar and in some cases superior to geologic conditions that have proven highly productive on land.
  • offshore reserves have been estimated at 21% of the world's proven reserves, with estimates that 40% to 50% of all future resources will come from offshore reserves.
  • Drilling offshore wells in deep water greater than 1000 feet (304.8 m) in depth, creates its own set of problems.
  • shallow depth sands of apparently artesian flow, are encountered. The depth of these sands and the pressures that they exhibit create a unique well design situation.
  • the unique well design is the result of being unable to hydrostatically control the shallow water flows (SWF) by the conventional method of returning the drilling fluid to the drilling rig.
  • SWF shallow water flows
  • the hydrostatic head generated by returning the fluid to the rig exceeds the fracture gradients of the rock above the SWF. Therefore, the well is designed in a manner that a fluid of the proper density returns only to the sea floor, riserless drilling.
  • the invention contemplates a system for storing, mixing and pumping drilling fluids on drilling vessels such as deep water rigs.
  • a method of drilling a sub-sea well comprising: (a) preparing a drilling fluid suitable for storage in a ballast tank, wherein said drilling fluid contains little or no particulate material and fluid density is provided at least in part by dissolved solids; (b) transporting the drilling fluid to a floating drilling vessel having at least one ballast tank; (c) pumping a quantity of the drilling fluid into said ballast tank or tanks of said drilling vessel while monitoring said pumping and distribution of said fluid into said tank or tanks so as to maintain balance of said vessel; and (d) pumping the drilling fluid from said ballast tank or tanks into the wellbore as it is being drilled while monitoring said pumping of said fluid from said tank so as to maintain balance of said vessel.
  • a process for storing drilling fluids on a drilling vessel including preparing a drilling fluid suitable for ballast tank storage, transporting the drilling fluid to a drilling vessel, pumping a quantity of the drilling fluid into at least one ballast tank compartment of the drilling vessel, and trimming the drilling vessel during the addition of the drilling fluid.
  • the drilling fluid provides a biostatic environment in the ballast tank compartment.
  • the drilling fluid pumped into the ballast tank contains little of no particulate material.
  • At least 10,000 bbls of drilling fluid are stored in the ballast tank.
  • a method for drilling a sub-sea well comprising (a) preparing a drilling fluid suitable for storage in at least one ballast tank; (b) transporting the drilling fluid to a drilling vessel; (c) pumping a quantity of the drilling fluid into a ballast tank compartment of a drilling vessel: and (d) pumping the drilling fluid into the wellbore as it is being drilled.
  • the method further comprises designing the drilling fluid based on an analysis of the geologic information gathered at the drilling site.
  • the drilling fluid provides a biostatic environment in the ballast tank compartment.
  • the method further comprises removing an amount of the drilling fluid from the ballast tank compartment and mixing the drilling fluid with a particulate material before pumping the drilling fluid into the wellbore.
  • the method further comprises trimming the drilling vessel during the addition and removal of the drilling fluid from the ballast tank compartment.
  • a method of drilling a sub-sea well comprising: (a) gathering geologic information about the drilling site; (b) preparing a drilling fluid based on the geologic information gathered about the drilling site, the drilling fluid being suitable for storage in the ballast tank compartment; (c) pumping at least 10,000 bbls of the drilling fluid into at least one ballast tank compartment of a drilling vessel; (d) removing an amount of the drilling fluid from that ballast tank compartment; (e) trimming the drilling vessel during the addition and removal of the drilling fluid from the ballast tank compartment; (f) admixing the drilling fluid with a particulate material; and (g) pumping the mixture of drilling fluid and particulate material into the wellbore as it is being drilled.
  • a drilling fluid is prepared, transported to a drilling vessel, pumped into a ballast tank compartment of the drilling vessel for storage until the drilling operation begins, removed from the ballast tank compartment, mixed with solid particulate matter and pumped into the wellbore during drilling.
  • the stored drilling fluid will be designed (1) to contain no undissolved solids, (2) to be rheologically stable, (3) to be biostatic, (4) to be capable of suspending particulate matter that is added in the drilling operation, and (5) to provide density through dissolved solids.
  • the present invention provides a process for storing drilling fluids in ballast tanks of drilling vessels and drilling fluid formulations suitable for ballast tank storage.
  • a drilling fluid is a liquid circulated through the wellbore during rotary drilling operations. In addition to its function of bringing cuttings to the surface, drilling fluid cools and lubricates the bit and drill stem, protects against blowouts by holding back subsurface pressures, and deposits a mud cake on the wall of the borehole to prevent loss of fluids to the formation. Drilling fluids are formulated to maintain the hydrostatic pressure within the wellbore necessary to prevent shallow water flows into the wellbore.
  • Drilling fluids are used throughout the drilling process.
  • a drilling operation requires a large quantity of drilling fluid (10,000 to 30,000 barrels (1590 to 4770 m 3 )) to complete the operation.
  • Such large quantities of drilling fluid present a problem for offshore drilling operations, since the drilling fluid is typically supplied by work boats or barges bringing the drilling fluid from land out to the drilling vessel.
  • bad weather can interrupt the supply of work boats and therefore the supply of drilling fluid to the drilling vessel.
  • the present invention addresses this problem by storing sufficient drilling fluid on the drilling vessel to reduce the dependency of a drilling operation on supplies brought in by work boats, thereby ensuring uninterrupted drilling in the event of inclement weather.
  • a number of drilling vessels (such as floating mini-tension leg platforms like the SeaStarTM, floating production systems with semi-submersible drilling and production equipment, tension leg platforms, and SPARTM platforms, and drillships) are designed with ballast tanks that are filled with fluid to provide platform stability.
  • the ballast tanks are typically filled with sea water and the water level raised or lowered as necessary to trim the platform.
  • One embodiment of the present invention utilizes ballast tanks of drilling vessels to store large quantities of drilling fluids in order to reduce the dependency of drilling vessels on the supply of work boats during the drilling operation.
  • Drilling fluid formulations are based on an analysis of geologic information gathered about or at the drilling site. Thus drilling fluids with the desired characteristics can be prepared for storage in the ballast compartment of a drilling vessel.
  • a period of predicted good weather is selected, preferably a period of at least two days of predicted good weather is selected.
  • the drilling fluid is loaded on work boats and transported to the drilling vessel where the drilling fluid is pumped into the vessel's ballast tank compartments for storage. Keeping the platform balanced or trim during this operation is important and requires a careful monitoring of pump action and drilling fluid distribution.
  • Drilling vessel ballast tanks typically have multiple compartments on each side of the drilling vessel. Individual compartments are emptied of fluid and refilled with drilling fluid in a sequence and pattern to keep the drilling vessel balanced or trim.
  • the drilling fluid is pumped from the ballast tanks and mixed with optional ingredients, such as sized solid particulate material like calcium carbonate or barium sulfate, in the mixing tanks of the drilling vessel. Once again it is important that all the pumping operations be planned to keep the platform trim throughout the operation.
  • the final drilling fluid formulation is then ready to be circulated through the wellbore during the drilling operation.
  • Drilling fluids are formulated to meet the requirements of the well site.
  • the density of the drilling fluid is designed to maintain the hydrostatic pressure within the wellbore to prevent shallow water flows.
  • Fluid density is provided by dissolved solids, including without limitation the solid salts of sodium, potassium, calcium and zinc and the organic acetate and formate salts of sodium, potassium and cesium.
  • a particular salt is selected to adjust the density of the drilling fluid based on environmental considerations, the required density, cost, and the freezing point of the required solution (highly concentrated solutions of certain salts have a high enough freezing point that they are subject to freezing in colder waters).
  • the drilling fluid should have sufficient carrying capacity to remove the bit cuttings from the wellbore.
  • Materials used to adjust the carrying capacity of the drilling fluid include without limitation hydroxyethyl cellulose, welan gum, guar gum, xanthum gum, polyacrylamide/polyacrylate, or carboxymethyl cellulose.
  • Drillers often encounter zones that accept large volumes of drilling fluid due to fractures, coarse sand, gravel, or other formations. Severe losses in drilling fluid can be controlled by circulating high concentrations of sized solids suspended in viscous fluids or gels. Such mixtures are referred to as lost circulation materials.
  • the lost circulation materials are designed to bridge and seal very permeable formations and to prevent fractures from growing.
  • Appropriate water soluble viscosifiers or suspension agents for drilling fluids are xanthan gum and N-VISTM HB (available from Barold Drilling Fluids, Houston, Texas).
  • Suitable sized solid particulates include barium sulfate, calcium carbonate, iron carbonate, and hematite. Additional fluid loss control can be provided by starch derivatives, polyacrylates, amps polymers, and lignin based materials.
  • drilling fluid that is to be stored in ballast tanks and used on a drilling vessel, is that any additional components that must be added to the drilling fluid during the drilling operation must be kept at a minimum. Since drilling vessels generally have limited mixing capacity, it is important to minimize the need for mixing additional materials. However, it is also important that drilling fluids to be stored in ballast tanks should not contain particulate material that could settle out of the drilling fluid, any sized solid particulate material such as barium sulfate, calcium carbonate, iron carbonate, or hematite must be mixed with the fluid on the drilling vessel before it is used during the drilling operation.
  • any sized solid particulate material such as barium sulfate, calcium carbonate, iron carbonate, or hematite must be mixed with the fluid on the drilling vessel before it is used during the drilling operation.
  • drilling fluid suitable for ballast tank storage and use on a drilling vessel
  • the fluid be rheologically stable and remain in a homogenous state while being stored.
  • the drilling fluid should provide a biostatic environment that would inhibit bacterial growth and the bacterial breakdown of certain drilling fluid components.
  • brine-based drilling fluids suitable for ballast tank storage are set forth below. The examples given below are meant to be illustrative and not limiting.

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Abstract

A method of drilling a sub-sea well comprising: (a) preparing a drilling fluid suitable for storage in a ballast tank, wherein said drilling fluid contains little or no particulate material and fluid density is provided at least in part by dissolved solids; (b) transporting the drilling fluid to a floating drilling vessel having at least one ballast tank; (c) pumping a quantity of the drilling fluid into said ballast tank or tanks of said drilling vessel while monitoring said pumping and distribution of said fluid into said tank or tanks so as to maintain balance of said vessel; and (d) pumping the drilling fluid from said ballast tank or tanks into the wellbore as it is being drilled while monitoring said pumping of said fluid from said tank so as to maintain balance of said vessel.

Description

  • The present invention relates in general to a brine-based drilling fluid and methods for storing fluids on drilling vessels, and more specifically to storing brine-based drilling fluids in drilling vessel ballast tanks.
  • For many years petroleum companies concentrated on developing oil and gas fields on land. But the world's appetite for energy sources, coupled with diminishing returns from land drilling, has driven petroleum companies to develop offshore reserves.
  • Sub-sea geologic sediments and structures are often similar and in some cases superior to geologic conditions that have proven highly productive on land. In fact, offshore reserves have been estimated at 21% of the world's proven reserves, with estimates that 40% to 50% of all future resources will come from offshore reserves.
  • A need exists for a method to store sufficient quantities of drilling fluids on a drilling vessel to reduce the dependency of a drilling operation on supplies brought in by work boats, thereby ensuring uninterrupted drilling in the event of inclement weather.
  • A further need exists for drilling fluid compositions suitable for storage on a drilling vessel.
  • Drilling offshore wells in deep water, greater than 1000 feet (304.8 m) in depth, creates its own set of problems. When drilling on the edge of the continental shelf, quite frequently pressured shallow depth sands, of apparently artesian flow, are encountered. The depth of these sands and the pressures that they exhibit create a unique well design situation.
  • The unique well design is the result of being unable to hydrostatically control the shallow water flows (SWF) by the conventional method of returning the drilling fluid to the drilling rig. The hydrostatic head generated by returning the fluid to the rig exceeds the fracture gradients of the rock above the SWF. Therefore, the well is designed in a manner that a fluid of the proper density returns only to the sea floor, riserless drilling.
  • In a riserless drilling situation, large volumes of drilling fluid are required due to the fact that the fluid is not returned to the rig and reused. Depending upon the depth of SWF, volumes from 10,000 to over 30,000 bbls (1590 to 4770 m3) of drilling fluid could be required. The surface mixing equipment of existing rigs is insufficient to store or prepare the large volumes of fluids required to drill riserless. To date, riserless drilling operations have been dependent upon work boats and barges to store and transport the required fluids that were prepared at land based facilities. Often, bad weather has interrupted the supply of work boats and therefore the supply of drilling fluid, causing the termination of drilling operations.
  • The invention contemplates a system for storing, mixing and pumping drilling fluids on drilling vessels such as deep water rigs.
  • According to a first aspect of the invention, there is provided a method of drilling a sub-sea well comprising: (a) preparing a drilling fluid suitable for storage in a ballast tank, wherein said drilling fluid contains little or no particulate material and fluid density is provided at least in part by dissolved solids; (b) transporting the drilling fluid to a floating drilling vessel having at least one ballast tank; (c) pumping a quantity of the drilling fluid into said ballast tank or tanks of said drilling vessel while monitoring said pumping and distribution of said fluid into said tank or tanks so as to maintain balance of said vessel; and (d) pumping the drilling fluid from said ballast tank or tanks into the wellbore as it is being drilled while monitoring said pumping of said fluid from said tank so as to maintain balance of said vessel.
  • According to a second aspect of the invention, there is provided a process for storing drilling fluids on a drilling vessel including preparing a drilling fluid suitable for ballast tank storage, transporting the drilling fluid to a drilling vessel, pumping a quantity of the drilling fluid into at least one ballast tank compartment of the drilling vessel, and trimming the drilling vessel during the addition of the drilling fluid.
  • In an embodiment, the drilling fluid provides a biostatic environment in the ballast tank compartment.
  • In another embodiment, the drilling fluid pumped into the ballast tank contains little of no particulate material.
  • In another embodiment, at least 10,000 bbls of drilling fluid are stored in the ballast tank.
  • According to a third aspect of the invention, there is provided a method for drilling a sub-sea well comprising (a) preparing a drilling fluid suitable for storage in at least one ballast tank; (b) transporting the drilling fluid to a drilling vessel; (c) pumping a quantity of the drilling fluid into a ballast tank compartment of a drilling vessel: and (d) pumping the drilling fluid into the wellbore as it is being drilled.
  • In an embodiment, the method further comprises designing the drilling fluid based on an analysis of the geologic information gathered at the drilling site.
  • In another embodiment, the drilling fluid provides a biostatic environment in the ballast tank compartment.
  • In another embodiment about 10,000 to 30,000 bbls are pumped into at least one ballast tank compartment.
  • In a further embodiment the method further comprises removing an amount of the drilling fluid from the ballast tank compartment and mixing the drilling fluid with a particulate material before pumping the drilling fluid into the wellbore.
  • In a further embodiment, the method further comprises trimming the drilling vessel during the addition and removal of the drilling fluid from the ballast tank compartment.
  • According to a fourth aspect of the invention, there is provided a method of drilling a sub-sea well comprising: (a) gathering geologic information about the drilling site; (b) preparing a drilling fluid based on the geologic information gathered about the drilling site, the drilling fluid being suitable for storage in the ballast tank compartment; (c) pumping at least 10,000 bbls of the drilling fluid into at least one ballast tank compartment of a drilling vessel; (d) removing an amount of the drilling fluid from that ballast tank compartment; (e) trimming the drilling vessel during the addition and removal of the drilling fluid from the ballast tank compartment; (f) admixing the drilling fluid with a particulate material; and (g) pumping the mixture of drilling fluid and particulate material into the wellbore as it is being drilled.
  • According to a fifth aspect of the invention, a drilling fluid is prepared, transported to a drilling vessel, pumped into a ballast tank compartment of the drilling vessel for storage until the drilling operation begins, removed from the ballast tank compartment, mixed with solid particulate matter and pumped into the wellbore during drilling.
  • The stored drilling fluid will be designed (1) to contain no undissolved solids, (2) to be rheologically stable, (3) to be biostatic, (4) to be capable of suspending particulate matter that is added in the drilling operation, and (5) to provide density through dissolved solids.
  • The foregoing has outlined, rather broadly, aspects of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the system for storing, mixing and pumping drilling fluids on a drilling vessel will be described hereinafter which forms the subject of the claims of the invention. It should be appreciated by those skilled in the art that the concept and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other processes or compositions for carrying out the same purpose of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.
  • The present invention provides a process for storing drilling fluids in ballast tanks of drilling vessels and drilling fluid formulations suitable for ballast tank storage.
  • As petroleum companies have turned to developing offshore oil and gas reserves, they have been faced with a number of problems. For example, a number or offshore wells have been lost due to shallow water flows.
  • The use of weighted drilling fluids during the drilling of offshore wells would be helpful in controlling shallow water flows. A drilling fluid is a liquid circulated through the wellbore during rotary drilling operations. In addition to its function of bringing cuttings to the surface, drilling fluid cools and lubricates the bit and drill stem, protects against blowouts by holding back subsurface pressures, and deposits a mud cake on the wall of the borehole to prevent loss of fluids to the formation. Drilling fluids are formulated to maintain the hydrostatic pressure within the wellbore necessary to prevent shallow water flows into the wellbore.
  • Drilling fluids are used throughout the drilling process. A drilling operation requires a large quantity of drilling fluid (10,000 to 30,000 barrels (1590 to 4770 m3)) to complete the operation. Such large quantities of drilling fluid present a problem for offshore drilling operations, since the drilling fluid is typically supplied by work boats or barges bringing the drilling fluid from land out to the drilling vessel. However, bad weather can interrupt the supply of work boats and therefore the supply of drilling fluid to the drilling vessel.
  • Whenever the supply of drilling fluid is terminated, the drilling must cease until the drilling fluid supply is once again available. Interrupted drilling operations require a larger overall quantity of drilling fluid, than uninterrupted drilling operations and such interruptions can put the well at risk of shallow water flows. The present invention addresses this problem by storing sufficient drilling fluid on the drilling vessel to reduce the dependency of a drilling operation on supplies brought in by work boats, thereby ensuring uninterrupted drilling in the event of inclement weather.
  • A number of drilling vessels (such as floating mini-tension leg platforms like the SeaStar™, floating production systems with semi-submersible drilling and production equipment, tension leg platforms, and SPAR™ platforms, and drillships) are designed with ballast tanks that are filled with fluid to provide platform stability. The ballast tanks are typically filled with sea water and the water level raised or lowered as necessary to trim the platform.
  • One embodiment of the present invention utilizes ballast tanks of drilling vessels to store large quantities of drilling fluids in order to reduce the dependency of drilling vessels on the supply of work boats during the drilling operation. Drilling fluid formulations are based on an analysis of geologic information gathered about or at the drilling site. Thus drilling fluids with the desired characteristics can be prepared for storage in the ballast compartment of a drilling vessel.
  • Once the drilling fluid is prepared, a period of predicted good weather is selected, preferably a period of at least two days of predicted good weather is selected. The drilling fluid is loaded on work boats and transported to the drilling vessel where the drilling fluid is pumped into the vessel's ballast tank compartments for storage. Keeping the platform balanced or trim during this operation is important and requires a careful monitoring of pump action and drilling fluid distribution.
  • Drilling vessel ballast tanks typically have multiple compartments on each side of the drilling vessel. Individual compartments are emptied of fluid and refilled with drilling fluid in a sequence and pattern to keep the drilling vessel balanced or trim.
  • When the drilling is ready to begin, the drilling fluid is pumped from the ballast tanks and mixed with optional ingredients, such as sized solid particulate material like calcium carbonate or barium sulfate, in the mixing tanks of the drilling vessel. Once again it is important that all the pumping operations be planned to keep the platform trim throughout the operation. The final drilling fluid formulation is then ready to be circulated through the wellbore during the drilling operation.
  • Drilling fluids are formulated to meet the requirements of the well site. For example, the density of the drilling fluid is designed to maintain the hydrostatic pressure within the wellbore to prevent shallow water flows. Fluid density is provided by dissolved solids, including without limitation the solid salts of sodium, potassium, calcium and zinc and the organic acetate and formate salts of sodium, potassium and cesium. A particular salt is selected to adjust the density of the drilling fluid based on environmental considerations, the required density, cost, and the freezing point of the required solution (highly concentrated solutions of certain salts have a high enough freezing point that they are subject to freezing in colder waters).
  • Furthermore, the drilling fluid should have sufficient carrying capacity to remove the bit cuttings from the wellbore. Materials used to adjust the carrying capacity of the drilling fluid include without limitation hydroxyethyl cellulose, welan gum, guar gum, xanthum gum, polyacrylamide/polyacrylate, or carboxymethyl cellulose.
  • Drillers often encounter zones that accept large volumes of drilling fluid due to fractures, coarse sand, gravel, or other formations. Severe losses in drilling fluid can be controlled by circulating high concentrations of sized solids suspended in viscous fluids or gels. Such mixtures are referred to as lost circulation materials. The lost circulation materials are designed to bridge and seal very permeable formations and to prevent fractures from growing. Appropriate water soluble viscosifiers or suspension agents for drilling fluids are xanthan gum and N-VIS™ HB (available from Barold Drilling Fluids, Houston, Texas). Suitable sized solid particulates include barium sulfate, calcium carbonate, iron carbonate, and hematite. Additional fluid loss control can be provided by starch derivatives, polyacrylates, amps polymers, and lignin based materials.
  • One major concern for drilling fluid that is to be stored in ballast tanks and used on a drilling vessel, is that any additional components that must be added to the drilling fluid during the drilling operation must be kept at a minimum. Since drilling vessels generally have limited mixing capacity, it is important to minimize the need for mixing additional materials. However, it is also important that drilling fluids to be stored in ballast tanks should not contain particulate material that could settle out of the drilling fluid, any sized solid particulate material such as barium sulfate, calcium carbonate, iron carbonate, or hematite must be mixed with the fluid on the drilling vessel before it is used during the drilling operation.
  • Yet another desirable feature of drilling fluid, suitable for ballast tank storage and use on a drilling vessel, is that the fluid be rheologically stable and remain in a homogenous state while being stored. For example, the drilling fluid should provide a biostatic environment that would inhibit bacterial growth and the bacterial breakdown of certain drilling fluid components. Examples of brine-based drilling fluids suitable for ballast tank storage are set forth below. The examples given below are meant to be illustrative and not limiting.
  • Example 1
  • Potassium Chloride Based Drilling Fluid
    Ingredients Per barrel
    9.7 lb/gal saturated KCl brine 1 bbl.
    N-VIS™ 1 lb.
    N-DRIL HT PLUS™ 4 lb.
    LIQUI-VIS EP™ 0.5 lb.
    Characteristics of the Drilling Fluid in Example 1
    Characteristics Measured Measurement
    Test 1 Test 2
    Stirred, min 30 30
    Temperature, °F 72 120
    Plastic viscosity, cP 14 11
    Yield point, lb/100 ft. 28 20
    10 Sec gel, lb/100 ft. 9 7
    10 Min gel, lb/100 ft. 12 11
    pH 7.6
    API filtrate, ml 6.8
    Fann 35 dial readings
    600 rpm 56 42
    300 rpm 42 31
    200 rpm 35 26
    100 rpm 26 20
    6 rpm 10 8
    3 rpm 9 7
  • Example 2
  • Sodium Chloride Based Drilling Fluid
    Ingredients Per barrel
    10.0 lb/gal saturated NaCl brine 1 bbl.
    N-VIS™ 1 lb.
    N-DRIL HT PLUS™ 4 lb.
    LIQUI-VIS EP™ 0.5 lb.
    Characteristics of the Drilling Fluid in Example 2
    Characteristics Measured Measurement
    Test 1 Test 2
    Stirred, min 30 30
    Temperature, °F 72 120
    Plastic viscosity, cP 18 14
    Yield point, lb/100 ft. 28 22
    10 Sec gel, lb/100 ft. 9 7
    10 Min gel, lb/100 ft. 11 11
    pH 7.3
    API filtrate, ml 6.4
    Fann 35 dial readings
    600 rpm 64 50
    300 rpm 46 36
    200 rpm 38 29
    100 rpm 28 23
    6 rpm 10 9
    3 rpm 9 7
  • Example 3
  • Calcium Chloride Based Drilling Fluid
    Ingredients Per barrel
    10.0 lb/gal saturated CaCl2 brine 1 bbl.
    N-VIS™* HB 1 lb.
    N-DRIL HT PLUS™ 4 lb.
    LIQUI-VIS EP™ 0.5 lb.
    Characteristics of the Drilling Fluid in Example 3
    Characteristics Measured Measurement
    Test 1 Test 2
    Stirred, min 30 30
    Temperature, °F 72 120
    Plastic viscosity, cP 38 27
    Yield point, lb/100 ft. 22 18
    10 Sec gel, lb/100 ft. 6 6
    10 Min gel, lb/100 ft. 9 8
    pH 5.8
    API filtrate, ml 3.8
    Fann 35 dial readings
    600 rpm 98 72
    300 rpm 60 45
    200 rpm 45 34
    100 rpm 28 22
    6 rpm 7 7
    3 rpm 6 6
  • Example 4
  • Calcium Bromide Based Drilling Fluid
    Ingredients Per barrel
    14.2 lb/gal CaBr2, brine 1 bbl.
    N-VIS™ HB 1 lb.
    N-DRIL HT PLUS™ 4 lb.
    LIQUI-VIS EP™ 0.5 lb.
    Characteristics of the Drilling Fluid in Example 4
    Characteristics Measured Measurement
    Test 1 Test 2
    Stirred, min 30 30
    Temperature, °F 72 120
    Plastic viscosity, cP 29 23
    Yield point, lb/100 ft. 14 12
    10 Sec gel, lb/100 ft. 2 2
    10 Min gel, lb/100 ft. 4 3
    pH 5.2
    API filtrate, ml 6.2
    Fann 35 dial readings
    600 rpm 72 58
    300 rpm 43 35
    200 rpm 32 25
    100 rpm 19 15
    6 rpm 4 3
    3 rpm 3 2
  • Example 5
  • Sodium Formate Brine Based Drilling Fluid
    Ingredients Per barrel
    11.1 lb/gal saturated sodium format brine 1 bbl.
    N-VIS™ 1 lb.
    N-DRIL HT PLUS™ 4 lb.
    Sodium hydroxide 0.1 lb.
    LIQUI-VIS EP™ 0.5 lb.
    Characteristics of the Drilling Fluid in Example 5
    Characteristics Measured Measurement
    Test 1 Test 2
    Stirred, min 30 30
    Temperature, °F 72 120
    Plastic viscosity, cP 26 17
    Yield point, lb/100 ft. 28 20
    10 Sec gel, lb/100 ft. 6 5
    10 Min gel, lb/100 ft. 8 7
    pH 10.7
    API filtrate, ml 4.6
    Fann 35 dial readings
    600 rpm 80 54
    300 rpm 54 37
    200 rpm 40 28
    100 rpm 25 20
    6 rpm 7 6
    3 rpm 6 5
  • Example 6
  • Potassium Formate Brine Based Drilling Fluid
    Ingredients Per barrel
    13.1 lb/gal saturated Potassium formate brine 1 bbl.
    N-VIS™ HB 1 lb.
    N-DRIL HT PLUS™ 4 lb.
    Potassium hydroxide 0.1 lb.
    LIQUI-VIS EP™ 0.5 lb.
    Characteristics of the Drilling Fluid in Example 6
    Characteristics Measured Measurement
    Test 1 Test 2
    Stirred, min 30 30
    Temperature, °F 72 120
    Plastic viscosity, cP 23 17
    Yield point, Ib/100 ft. 12 12
    10 Sec gel, lb/100 ft. 5 3
    10 Min gel, lb/100 ft. 7 5
    pH 10.6
    API filtrate, ml 4.2
    Fann 35 dial readings
    600 rpm 58 46
    300 rpm 35 29
    200 rpm 27 21
    100 rpm 17 14
    6 rpm 6 4
    3 rpm 5 3
  • Example 7
  • Sodium Bromide Based Drilling Fluid
    Ingredients Per barrel
    12.7 lb/gal saturated NaBr brine 1 bbl.
    N-VIS™ 1 lb.
    N-DRIL HT PLUS™ 4 lb.
    LIQUI-VIS EP™ 0.5 lb.
    Characteristic of the Drilling Fluid in Example 7
    Characteristics Measured Measurement
    Test 1 Test 2
    Stirred, min 30 30
    Temperature, °F 72 120
    Plastic viscosity, cP 18 13
    Yield point, lb/100 ft. 27 21
    10 Sec gel, lb/100 ft. 6 5
    10 Min gel, lb/100 ft. 8 7
    pH 6.2
    API filtrate, ml 3.6
    Fann 35 dial readings
    600 rpm 63 47
    300 rpm 45 34
    200 rpm 36 26
    100 rpm 25 19
    6 rpm 7 6
    3 rpm 6 5
  • Numerous modifications and variations in the process for storing, mixing and using drilling fluids on a drilling vessel and in the composition of the drilling fluid composition are possible in light of the above teachings. It is therefore understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.

Claims (9)

  1. A method of drilling a sub-sea well comprising: (a) preparing a drilling fluid suitable for storage in a ballast tank, wherein said drilling fluid contains little or no particulate material and fluid density is provided at least in part by dissolved solids; (b) transporting the drilling fluid to a floating drilling vessel having at least one ballast tank; (c) pumping a quantity of the drilling fluid into said ballast tank or tanks of said drilling vessel while monitoring said pumping and distribution of said fluid into said tank or tanks so as to maintain balance of said vessel; and (d) pumping the drilling fluid from said ballast tank or tanks into the wellbore as it is being drilled while monitoring said pumping of said fluid from said tank so as to maintain balance of said vessel.
  2. A method according to claim 1, further comprising designing the drilling fluid based on an analysis of the geologic information gathered at the drilling site, such that said dissolved solids are selected from the group comprising solid salts of sodium, potassium, calcium, and zinc, and the organic acetate and formate salts of sodium, potassium and cesium, and a particular salt from said group is selected to adjust the density of the drilling fluid based on considerations comprising environmental considerations, the required density for drilling the well, temperature of the sea waters and freezing point of the fluid.
  3. A method according to claim 1 or 2, wherein the drilling fluid provides a biostatic environment in the ballast tank.
  4. A method according to claim 1, 2 or 3, wherein about 10,000 to about 30,000 bbls are pumped into said ballast tank or tanks.
  5. A method according to any preceding claim, further comprising removing an amount of the drilling fluid from the ballast tank and mixing said amount of the drilling fluid with a particulate material before pumping the drilling fluid into the wellbore.
  6. A method according to any preceding claim, wherein said drilling is in deep water.
  7. A method according to any preceding claim, further comprising returning said drilling fluid to the sea floor.
  8. A method according to any preceding claim, wherein said drilling is riserless drilling.
  9. A method according to any preceding claim, wherein sufficient quantity of drilling fluid is transported to said vessel and pumped into said ballast tank or tanks such that said well may be drilled with such fluid without delays for additional fluid to be brought to said vessel.
EP05075864A 1998-09-04 1999-08-25 Brine-based drilling fluids for ballast tank storage Withdrawn EP1571078A1 (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
US9921398P 1998-09-04 1998-09-04
US99213P 1998-09-04
US294758 1999-04-19
US09/294,758 US6315061B1 (en) 1998-09-04 1999-04-19 Brine-based drilling fluids for ballast tank storage
EP99945108A EP1107904B1 (en) 1998-09-04 1999-08-25 Brine-based drilling fluids for ballast tank storage

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EP1571078A1 true EP1571078A1 (en) 2005-09-07

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024017053A1 (en) * 2022-07-20 2024-01-25 深圳中科翎碳生物科技有限公司 Ship carbon dioxide tail gas treatment system

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4062313A (en) * 1975-09-25 1977-12-13 Standard Oil Company (Indiana) Installation of vertically moored platforms
GB2195685A (en) * 1986-10-04 1988-04-13 Prechem Limited Additives for controlling or modifying thixotropic properties
US4872118A (en) * 1984-08-09 1989-10-03 Naidenov Evgeny V System for automated monitoring of trim and stability of a vessel
US4966495A (en) * 1988-07-19 1990-10-30 Goldman Jerome L Semisubmersible vessel with captured constant tension buoy
EP0617106A1 (en) * 1993-03-22 1994-09-28 Phillips Petroleum Company Fluid composition comprising a metal aluminate or a viscosity promoter and a magnesium compound and process using the composition
US5643858A (en) * 1992-02-15 1997-07-01 Brunner Mond & Company Limited High density aqueous compositions
GB2310634A (en) * 1996-02-27 1997-09-03 Mp Semi-Submersible Vessels
US6315061B1 (en) * 1998-09-04 2001-11-13 Halliburton Energy Services, Inc. Brine-based drilling fluids for ballast tank storage

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4062313A (en) * 1975-09-25 1977-12-13 Standard Oil Company (Indiana) Installation of vertically moored platforms
US4872118A (en) * 1984-08-09 1989-10-03 Naidenov Evgeny V System for automated monitoring of trim and stability of a vessel
GB2195685A (en) * 1986-10-04 1988-04-13 Prechem Limited Additives for controlling or modifying thixotropic properties
US4966495A (en) * 1988-07-19 1990-10-30 Goldman Jerome L Semisubmersible vessel with captured constant tension buoy
US5643858A (en) * 1992-02-15 1997-07-01 Brunner Mond & Company Limited High density aqueous compositions
EP0617106A1 (en) * 1993-03-22 1994-09-28 Phillips Petroleum Company Fluid composition comprising a metal aluminate or a viscosity promoter and a magnesium compound and process using the composition
GB2310634A (en) * 1996-02-27 1997-09-03 Mp Semi-Submersible Vessels
US6315061B1 (en) * 1998-09-04 2001-11-13 Halliburton Energy Services, Inc. Brine-based drilling fluids for ballast tank storage

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024017053A1 (en) * 2022-07-20 2024-01-25 深圳中科翎碳生物科技有限公司 Ship carbon dioxide tail gas treatment system

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