CN-117821031-B - Consolidated plugging material for oil-based drilling fluid and preparation method and application thereof

Abstract

The invention relates to a consolidated plugging material for oil-based drilling fluid, a preparation method and application thereof, wherein the consolidated plugging material for the oil-based drilling fluid comprises oil-based gel, a consolidated material and a cross-linking agent; the oil-based gel comprises base oil, castor oil-based prepolymer containing terminal-NCO groups and oleophilic nano silicon dioxide, and the consolidation material comprises oil-based drilling cuttings powder, lime and organic soil. According to the consolidation plugging material for the oil-based drilling fluid, the mixed system of the oil-based gel, the solid phase material and the cross-linking agent is adopted, so that the plugging layer mainly comprising the oil-based gel and the solid phase material is formed in the using process, the plugging success rate of the oil-based drilling fluid leakage can be effectively improved, and the strength of the solidified layer after solidification can reach more than 5 MPa.

Inventors

• SHI HE
• GENG YUAN
• FENG JIE
• GAO SHAN
• Meng Sicong
• XU MENGXIAO
• Kou Yahao
• NI XIAOXIAO
• ZHANG JIAQI
• YAN LILI
• LIU RENTONG
• WANG JIANHUA
• YANG HAIJUN
• CHENG RONGCHAO
• WANG MAOGONG

Assignees

• 中国石油天然气集团有限公司
• 中国石油集团工程技术研究院有限公司

Dates

Publication Date

20260512

Application Date

20230630

Claims (7)

1. 1. The consolidation plugging material for the oil-based drilling fluid is characterized by comprising, by weight, 30-70 parts of oil-based gel, 30-70 parts of a consolidation material, 2-7 parts of a cross-linking agent and 3-10 parts of a retarder; the oil-based gel comprises 100-110 parts of base oil, 40-80 parts of castor oil-based prepolymer containing terminal-NCO groups and 5-10 parts of oleophylic nano-silica; The base oil comprises 1 or a combination of at least 2 of 0# diesel, 3# white oil, 5# white oil, gas oil, linear paraffin, or linear alpha olefin; The castor oil based prepolymer containing terminal-NCO groups is prepared by mixing castor oil, isocyanate monomers and an initiator, and then reacting, wherein the isocyanate monomers comprise 1 or at least 2 of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate or lysine diisocyanate, and the initiator comprises 1 or at least 2 of azodiisobutyronitrile, zinc isooctanoate, tin isooctanoate, bismuth isooctanoate or dibutyltin dilaurate; the consolidation material comprises 50-80 parts of oil-based drilling cuttings powder, 10-20 parts of lime and 10-20 parts of organic soil; The cross-linking agent comprises 1 or a combination of at least 2 of trimethylolpropane, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-isopropylimidazole, tetrachlorophthalic anhydride, hexahydrophthalic anhydride, diethylenetriamine, triethylenetetramine, dimethylaminopropylamine or diethylaminopropylamine; The retarder is a high-temperature retarder, and the high-temperature retarder comprises 1 or a combination of at least 2 of diethyl malonate, methyl ethyl ketoxime, acetone oxime or caprolactam; The oleophylic nano-silica is purchased from Shanghai Kaijin chemical industry Co., ltd., model R972, and the average particle size is 30nm.
2. 2. The consolidated lost circulation material for oil-based drilling fluids of claim 1, wherein the base oil comprises a base oil for oil-based drilling fluids.
3. 3. The consolidated lost circulation material for oil-based drilling fluids of claim 1, wherein the castor oil has a purity of >70%.
4. 4. A method for preparing a consolidated plugging material for an oil-based drilling fluid according to any one of claims 1-3, wherein the preparation method comprises adding the consolidated material, a cross-linking agent and a retarder to an oil-based gel according to a formula and stirring to obtain the consolidated plugging material suitable for the oil-based drilling fluid.
5. 5. The process according to claim 4, wherein the stirring is carried out at a stirring rate of 600 to 800r/min.
6. 6. The process according to claim 4, wherein the stirring time of the stirring is 30 to 50 minutes.
7. 7. Use of the consolidated plugging material for oil-based drilling fluids according to any of claims 1-3 for plugging lost circulation of oil-based drilling fluids during drilling with the consolidated plugging material for oil-based drilling fluids.

Description

Consolidated plugging material for oil-based drilling fluid and preparation method and application thereof Technical Field The invention relates to the technical field of oil-based drilling fluid for petroleum drilling, in particular to a consolidation plugging material for oil-based drilling fluid, a preparation method and application thereof. Background At present, the problem of lost circulation of oil-based drilling fluid is ubiquitous and can not be effectively solved due to the development of the lamellar cracks of the shale stratum, and the shale oil-gas efficient development is one of main reasons for restricting the efficient development of shale oil-gas. At present, a plugging technology of water-based drilling fluid is mainly adopted for oil-based drilling fluid leakage, while-drilling plugging and bridging slurry plugging are mainly adopted in the early stage, and cement plugging is changed after the effect is poor. The method comprises the steps of judging a leakage layer, determining the occurrence of the leakage, determining the depth of the leakage layer, measuring the leakage speed, directly adding leakage plugging materials into the oil-based drilling fluid and keeping circulation if the leakage speed is leakage, enabling a drill bit to normally drill, observing the drop of leakage, stopping a slurry pump if the leakage speed is middle-or large-scale leakage, stopping drilling, configuring new oil-based slurry in an independent slurry tank, adding the leakage plugging materials, stirring uniformly to obtain the plugging slurry, for the middle-scale leakage, not taking off the drill bit, directly enabling the drill bit to be positioned below the leakage layer or the leakage layer, for the large-scale leakage, taking off a drill rod, installing a plurality of times above the drill bit to activate a bypass valve, then enabling the drill bit to drop to the leakage layer, throwing a ball to open a bypass outlet, starting the slurry pump, and injecting the plugging slurry into the leakage layer to plug. The construction method can pertinently perform plugging, has high plugging success rate and good bearing capacity. However, the plugging while drilling and bridging slurry plugging schemes often cannot be effective due to a series of reasons such as the surface oleophilic wetting of the lost circulation fracture, the hydrophilic and oleophobic plugging material, the mismatching of the plugging material size with the fracture, and the like. Cement has poor pollution resistance to oil-based drilling fluid, poor consolidation effect after being mixed into the oil-based drilling fluid, and plugging success rate is far lower than that of water-based drilling fluid. Finally, when the method is repeated for a plurality of times and is still invalid, the oil-based drilling fluid is often replaced by the water-based drilling fluid and then the plugging operation is carried out, so that the loss time is increased, and the engineering progress is greatly delayed. Therefore, the consolidation plugging material suitable for the oil-based drilling fluid is developed, and has very important significance for improving the plugging success rate of the oil-based drilling fluid on the efficient development of shale oil gas, aiming at the defects of the prior art, in particular the defects that the existing plugging material has poor compatibility with the oil-based drilling fluid, is not matched with the size of a crack and is difficult to reside on the surface of the oil-wetted crack to form an effective plugging layer. Disclosure of Invention In view of the problems existing in the prior art, the invention aims to provide a consolidation plugging material for oil-based drilling fluid, a preparation method and application thereof, when oil-based drilling fluid leaks, the plugging material can be pumped into a leakage crack, and is consolidated at reasonable temperature and time to form a plugging layer with sufficient strength and strong residence capacity on an oil wetting surface, so that the plugging success rate of the oil-based drilling fluid is effectively improved, the economic loss and the manpower and material resource loss caused by repeated plugging are reduced, and the problems that the compatibility of the existing plugging material and the oil-based drilling fluid is poor, the plugging material is not matched with the size of the crack, and an effective plugging layer is difficult to reside on the oil wetting crack surface are solved. To achieve the purpose, the invention adopts the following technical scheme: in a first aspect, the invention provides a consolidated plugging material for oil-based drilling fluid, which comprises oil-based gel, a consolidated material and a cross-linking agent; the oil-based gel comprises base oil, castor oil-based prepolymer containing terminal-NCO groups and oleophilic nano silicon dioxide; The consolidation materials include oil-based cuttings powder, lime and org