A filtrate reducer for oil-based drilling fluid and oil-based drilling fluid

Abstract

The application relates to the field of oil and gas technology, and provides a filtrate reducer for oil-based drilling fluid, which comprises the following components: polyvinylidene chloride, fine calcium and polyethylene wax. The filtrate reducer is novel in component, can ensure the reduction of the filtrate loss of the drilling fluid, and effectively solves the problem of black removal of conventional oil-based drilling fluid. The application also provides an oil-based drilling fluid containing the filtrate reducer.

Description

Technical Field

[0001] This invention relates to the field of oil and gas technology, and more specifically to a filtration loss reducer for oil-based drilling fluids and an oil-based drilling fluid containing the filtration loss reducer. Background Technology

[0002] During drilling, due to pressure differentials, water in the drilling fluid inevitably leaks through the wellbore into the formation, causing fluid loss. Current technology typically involves adding fluid loss reducers to the drilling fluid to control the amount of fluid loss.

[0003] In the early stages of oil-based drilling fluid use, asphalt-based products were widely used as filtration reducers. However, due to environmental regulations, their use has faced increasing restrictions. Modified humic acids are more environmentally friendly than asphalt-based filtration reducers and have a relatively smaller impact on drilling fluid rheology, leading to some promotion in recent years. However, compared to asphalt-based products, their overall temperature resistance is inferior, and their application is limited in some environmentally sensitive areas due to color variations. Currently, some international markets (offshore operating areas such as Abu Dhabi and Malaysia) have specific requirements regarding the color (de-blackening) of oil-based drilling fluid filtration reducers, making the development of other types of filtration reducers for oil-based drilling fluids highly meaningful. Summary of the Invention

[0004] The purpose of this invention is to provide a filtration loss reducer for oil-based drilling fluids. This filtration loss reducer has a novel composition and effectively solves the problem of blackening conventional oil-based drilling fluids while ensuring a reduction in drilling fluid filtration loss. This invention also provides an oil-based drilling fluid containing this filtration loss reducer.

[0005] According to the present invention, a filtration loss reducer for oil-based drilling fluid is provided, comprising the following components: polyvinylidene chloride, fine calcium, and polyethylene wax.

[0006] According to one embodiment of the present invention, the filtration loss reducing agent is composed of 60-80% polyvinylidene chloride, 10-20% fine calcium, and 10-20% polyethylene wax by mass percentage, wherein the sum of the mass percentages of each component is 100%.

[0007] According to one embodiment of the present invention, the fineness of the calcium carbonate is 1250-2000 mesh.

[0008] According to one embodiment of the present invention, the filtration loss reducer is composed of 80% polyvinylidene chloride, 10% 1250-mesh fine calcium, and 10% polyethylene wax by mass percentage.

[0009] According to one embodiment of the present invention, the filtration loss reducer is composed of 60% polyvinylidene chloride, 20% 1500-mesh calcium carbonate, and 20% polyethylene wax by mass percentage.

[0010] According to one embodiment of the present invention, the filtration loss reducer is composed of 70% polyvinylidene chloride, 15% 2000-mesh fine calcium, and 15% polyethylene wax by mass percentage.

[0011] According to the present invention, an oil-based drilling fluid is provided, comprising the above-mentioned filtration loss reducer.

[0012] According to one embodiment of the present invention, the oil-based drilling fluid comprises a solid phase component consisting of a primary emulsifier, an auxiliary emulsifier, a flow pattern regulator, Ca(OH)2, a viscosity enhancer, a filtration loss reducer, and barite in a mass ratio of 3:2-2.5:0-0.3:2.5-3:1.3-3:2-3:57.5-108, as well as white oil and a CaCl2 aqueous solution with a concentration of 20%-25%, wherein the liquid-to-solid ratio of white oil to the solid phase component is 0.5-1.2 ml / g, and the liquid-to-solid ratio of the CaCl2 aqueous solution to the solid phase component is 0.3-1.2 ml / g.

[0013] According to one embodiment of the present invention, oil-based drilling fluid is prepared by the following steps:

[0014] Add white oil, primary emulsifier, and secondary emulsifier to a container, and selectively add flow conditioner, and stir until homogeneous;

[0015] Add CaCl2 aqueous solution and stir until homogeneous;

[0016] Add Ca(OH)2 and stir well;

[0017] Add the thickening agent and mix well;

[0018] Add the filtration loss reducer and stir well;

[0019] Add the barite group and stir well.

[0020] According to one embodiment of the present invention, the oil-based drilling fluid is stirred at a speed of 11,000 r / min during the preparation process.

[0021] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0022] 1. The oil-based filtration loss reducer of this invention can completely replace asphalt-based products in oil-based drilling fluids, and can effectively solve the problem of blackening conventional oil-based drilling fluids.

[0023] 2. Polyvinylidene chloride is insoluble in white oil. The presence of dichlorodi ...

[0024] 3. Polyethylene wax is insoluble in white oil at low temperatures, but disperses in white oil as a waxy substance. It is miscible with white oil at high temperatures, and this process is reversible. This allows for constant rheological control of oil-based drilling fluids, avoiding the problem of increased viscosity of oil-based drilling fluids after the addition of asphalt-based treatment agents. Detailed Implementation

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] The oil-based drilling fluid filtration reducer according to the present invention generally comprises the following components: polyvinylidene chloride, fine calcium, and polyethylene wax. The components are mixed in the following mass percentages: 60-80% polyvinylidene chloride, 10-20% fine calcium, and 10-20% polyethylene wax, with the sum of the mass percentages of all components being 100%. Preferably, the fineness of the fine calcium is between 1250 mesh and 2000 mesh.

[0027] The present invention also provides an oil-based drilling fluid containing the above-mentioned filtration loss reducer. The oil-based drilling fluid generally comprises a solid phase component consisting of a main emulsifier, an auxiliary emulsifier, a flow pattern regulator, Ca(OH)2, a viscosity enhancer, a filtration loss reducer, and barite in a mass ratio of 3:2-2.5:0-0.3:2.5-3:1.3-3:2-3:57.5-108, as well as white oil and a CaCl2 aqueous solution with a concentration of 20%-25%. The liquid-solid ratio of white oil to solid phase component is 0.5-1.2 ml / g, and the liquid-solid ratio of CaCl2 aqueous solution to solid phase component is 0.3-1.2 ml / g.

[0028] The above components can be used to prepare organic drilling fluid through the following steps:

[0029] S01: Add white oil, primary emulsifier and secondary emulsifier to a container, and selectively add flow conditioner, and stir at high speed for a period of time until the mixture is uniform;

[0030] SO2: Add CaCl2 aqueous solution and stir at high speed for a period of time until the mixture is uniform;

[0031] SO3: Add Ca(OH)2 and stir at high speed for a period of time until the mixture is uniform;

[0032] S04: Add thickening agent and stir at high speed for a period of time until the mixture is uniform;

[0033] S05: Add the filtration loss reducer and stir at high speed for a period of time until the mixture is uniform;

[0034] S06: Add barite group and stir at high speed for a period of time until it is evenly mixed.

[0035] In examples of the present invention, the stirring speed can be as high as 11,000 r / min.

[0036] The present invention will be further described below with reference to specific embodiments and comparative examples. All components in the following embodiments were purchased from commercially available products. Specifically, polyvinylidene chloride (PVDC) was from Dow Chemical Company, USA; polyethylene wax was a product of Qingdao Sainuo New Materials Co., Ltd.; the main emulsifier BZ-OPE was produced by Bohai Drilling Engineering Co., Ltd.; the auxiliary emulsifier BZ-OSE was produced by Bohai Drilling Engineering Co., Ltd.; the viscosity enhancer BZ-OC was produced by Bohai Drilling Engineering Co., Ltd.; and the flow pattern modifier was produced by Bohai Drilling Engineering Co., Ltd. Alternatively, those skilled in the art may also use products from other manufacturers as raw materials for preparing the filtration loss reducer and organic drilling fluid of this application.

[0037] Example 1

[0038] In this embodiment, the filtration loss reducer for the oil-based drilling fluid is composed of 80% polyvinylidene chloride, 10% 1250-mesh fine calcium, and 10% polyethylene wax by mass percentage.

[0039] Example 2

[0040] The filtration loss reducer of the oil-based drilling fluid in this embodiment is composed of 60% polyvinylidene chloride, 20% 1500-mesh fine calcium, and 20% polyethylene wax by mass percentage.

[0041] Example 3

[0042] The filtration loss reducer of the oil-based drilling fluid in this embodiment is composed of 70% polyvinylidene chloride, 15% 2000-mesh fine calcium, and 15% polyethylene wax by mass percentage.

[0043] Comparative Example 1

[0044] This comparative example uses BZ-OFL, an oil-based drilling fluid filtration reducer produced by Bohai Drilling Engineering Co., Ltd.

[0045] Comparative Example 2

[0046] This comparative example uses HIFLO, an oil-based drilling fluid filtration reducer produced by Jingzhou Jiahe Technology Co., Ltd.

[0047] Comparative Example 3

[0048] This comparative example uses MOHFR, an oil-based drilling fluid filtration reducer produced by Hubei Hanko New Technology Co., Ltd.

[0049] Comparative Example 4

[0050] This comparative example is TP-L4, an oil-based drilling fluid filtration reducer manufactured by United Technologies Asia Pacific Limited (Hong Kong).

[0051] Comparative Example 5

[0052] This comparative example is an oil-based drilling fluid filtration reducer: oxidized asphalt, produced by Qingdao Tianyi Chemical Co., Ltd.

[0053] Test 1

[0054] The oil-based drilling fluid filtration reducers prepared in Examples 1-3, as well as commercially available oil-based drilling fluid filtration reducers, were evaluated in the laboratory. The evaluation method was as follows:

[0055] S11: Add 240mL of No. 5 white oil, 9.0g of primary emulsifier BZ-OPE, and 6.0g of secondary emulsifier BZ-OSE to a high-speed stirring cup, and stir at 11000r / min for 5min.

[0056] S12: Add 60 mL of CaCl2 (25%) aqueous solution and stir at 11000 r / min for 10 min;

[0057] S13: Add 9.0g Ca(OH)2 and stir at high speed for 10 minutes;

[0058] S14: Add 9.0g of thickening agent BZ-OC and stir at 11000r / min for 30min;

[0059] S15: Add 9.0g of oil-based drilling fluid filtration reducer and stir at 11000r / min for 20 min.

[0060] S16: Add 172.5g of barite and stir at 11000r / min for 40min;

[0061] S17: Pour this oil-based drilling fluid into an aging tank, roll it at a constant temperature of 150℃ for 16 hours, take out the sample and let it reach room temperature, then stir it at 11000r / min for 20 minutes.

[0062] S18: Filtration loss at 150℃ under high temperature and high pressure shall be determined in accordance with GB / T 16783.2.

[0063] The test results are shown in Table 1:

[0064] Table 1. Results of High Temperature and High Pressure Filtration Loss Test

[0065]

[0066] The experimental data from Test 1 show that the oil-based drilling fluid filtration reducer disclosed in this invention has a good filtration loss control effect.

[0067] Test 2

[0068] The oil-based drilling fluid filtration reducers prepared in Examples 1-3, and commercially available oxidized asphalt were evaluated in the laboratory for an organic drilling fluid with the following component ratio: 278 mL of 5# white oil + 15 g of primary emulsifier BZ-OPE + 12.5 g of auxiliary emulsifier BZ-OSE + 1.5 g of flow modifier BZ-ORM + 12.5 g of Ca(OH)2 + 6.5 g of viscosity enhancer BZ-OC + 10 g of filtration reducer + 70 mL of CaCl2 (20%) + 540 g of barite.

[0069] The evaluation method specifically includes the following steps:

[0070] S21: Weigh out the main emulsifier BZ-OPE, auxiliary emulsifier BZ-OSE, and flow conditioner BZ-ORM according to the dosage in the formula and add them to the high-speed stirring cup. Add No. 5 white oil and stir at 11000r / min for 5min.

[0071] S22: Add CaCl2 (20%) aqueous solution and stir at 11000 r / min for 10 min;

[0072] S23: Add Ca(OH)2 and stir at 11000r / min for 10min;

[0073] S24: Add thickening agent BZ-OC and stir at 11000r / min for 30min;

[0074] S25: Add a filtration reducer for oil-based drilling fluid and stir at 11000 r / min for 20 min;

[0075] S26: Add barite and stir at 11000 r / min for 40 min to complete the preparation;

[0076] S27: Performance test before aging: Measured at 65℃±1℃ according to GB / T 16783.2. ES(V);

[0077] S28: Performance test after aging: After rolling at a constant temperature of 150℃ for 16 hours, the sample was taken out and placed at room temperature. It was then stirred at high speed of 11000r / min for 1 hour, and the ES was tested immediately.

[0078] S29: Subsequently, its properties were determined according to GB / T 16783.2 at 65℃±1℃. ES(V), 150℃ high temperature and high pressure filtration loss.

[0079] The test results are shown in Table 2:

[0080] Table 2 Results of High Temperature and High Pressure Filtration Loss Test

[0081]

[0082]

[0083] The experimental data from Test 2 show that the oil-based drilling fluid filtration reducer disclosed in this invention has a lower viscosity effect and better filtration loss control effect compared with asphalt-based filtration reducers.

[0084] It should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0085] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. An oil-based drilling fluid, characterized in that, The mixture comprises a solid phase component consisting of a main emulsifier, an auxiliary emulsifier, a flow pattern regulator, Ca(OH)2, a viscosity improver, a filtration loss reducer, and barite in a mass ratio of 3:2~2.5:0~0.3:2.5~3:1.3~3:2~3:57.5~108, as well as white oil and a CaCl2 aqueous solution with a concentration of 20%~25%, wherein the liquid-solid ratio of the white oil to the solid phase component is 0.5~1.2 ml / g, and the liquid-solid ratio of the CaCl2 aqueous solution to the solid phase component is 0.3~1.2 ml / g. The filtration loss reducer is composed of 60-80% polyvinylidene chloride, 10-20% fine calcium, and 10-20% polyethylene wax by mass percentage, with the sum of the mass percentages of each component being 100%.

2. The oil-based drilling fluid according to claim 1, characterized in that, The fineness of the calcium carbonate is 1250-2000 mesh.

3. The oil-based drilling fluid according to claim 1, characterized in that, The filtration loss reducer is composed of 80% polyvinylidene chloride, 10% 1250-mesh fine calcium, and 10% polyethylene wax by mass percentage.

4. The oil-based drilling fluid according to claim 1, characterized in that, The filtration loss reducer is composed of 60% polyvinylidene chloride, 20% 1500-mesh fine calcium, and 20% polyethylene wax by mass percentage.

5. The oil-based drilling fluid according to claim 1, characterized in that, The filtration loss reducer is composed of 70% polyvinylidene chloride, 15% 2000-mesh fine calcium, and 15% polyethylene wax by mass percentage.

6. The oil-based drilling fluid according to claim 1, characterized in that, The oil-based drilling fluid is prepared through the following steps: Add the white oil, the primary emulsifier, and the secondary emulsifier to a container, and selectively add a flow pattern regulator, and stir until homogeneous; Add the CaCl2 aqueous solution and stir until homogeneous; Add the Ca(OH)2 and stir until homogeneous; Add the viscosity improver and stir until well mixed; Add the filtration loss reducer and stir until homogeneous; Add the barite group and stir until homogeneous.

7. The oil-based drilling fluid according to claim 6, characterized in that, The oil-based drilling fluid is stirred at a speed of 11,000 r / min during the preparation process.

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