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3 Status Quo of Methods for Evaluating Filtration Performance and Mud Cake Quality of Drilling Fluid
4 Progresses in Studying Drilling Fluid Nano Material Plugging Agents
5 Drilling Fluid Technology for “Three High” Wells in Qaidam Basin in Qinghai
6 Synthesis and Evaluation of A Primary Emulsifier for High Temperature Oil Base Drilling Fluid
7 A New Fracturing Fluid with Temperature Resistance of 230℃
8 Development of Extreme Pressure Anti-wear Lubricant MPA for Water Base Drilling Fluids
9 Plugging Micro-fractures to Prevent Gas-cut in Fractured Gas Reservoir Drilling
10 Progress in Studying Cement Sheath Failure in Perforated Wells
2 Study and Performance Evaluation of Ultra-High Temperature High Density Oil Based Drilling Fluids
3 Synthesis and Evaluation of A Primary Emulsifier for High Temperature Oil Base Drilling Fluid
4 Hole Cleaning Technology for Horizontal and Deviated Drilling: Progress Made and Prospect
5 Progresses in Studying Drilling Fluid Nano Material Plugging Agents
6 Challenges, Developments, and Suggestions for Drilling Fluid Technology in China
9 A New Fracturing Fluid with Temperature Resistance of 230℃
10 High Performance Water Base Drilling Fluid for Shale Gas Drilling
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2025, 42(5): 567-574.
doi: 10.12358/j.issn.1001-5620.2025.05.001
Abstract:
As wells are drilled deeper and deeper to explore nonconventional oil and gas resources, drilling fluids, downhole tools and detection instrument are experiencing higher formation temperatures, and high efficiency cooling technology is urgently required. The methods of cooling a drilling fluid presently in use include natural cooling and cooling with surface instrument, whose cooling effect is limited. Phase change materials have advantages of high heat storage density and adjustable phase change temperature, hence can be used in a specific well section to achieve temperature response. With phase change materials, precise cooling in a depth near a downhole device such as RSD and LWD can be achieved, and phase change materials are thus becoming the research hotspot in drilling fluid cooling technology. Presently phase change materials though have been widely used in photothermal storage of solar energy, building temperature regulation as well as heat management for electronic devices etc., their use in deep and ultra-deep well drilling and exploration is still in an initial exploration stage. This paper focuses on the classification of phase change materials, the research status of medium and high temperature phase change materials, the properties of phase change materials required for use in drilling fluids, as well as the existing literatures on application studies of drilling fluid cooling. In the future, cost effective phase change materials of high thermal conductivity can be developed through numerical simulation and field test. By strengthening multifunction design of these phase change materials, optimizing their compatibility with drilling fluids, and investigating environmentally friendly, highly efficient, stable and intelligent new phase change materials with multiple functions such as cooling, lubricating and reservoir protection etc., an innovative solution to drilling fluid technology can be developed.
As wells are drilled deeper and deeper to explore nonconventional oil and gas resources, drilling fluids, downhole tools and detection instrument are experiencing higher formation temperatures, and high efficiency cooling technology is urgently required. The methods of cooling a drilling fluid presently in use include natural cooling and cooling with surface instrument, whose cooling effect is limited. Phase change materials have advantages of high heat storage density and adjustable phase change temperature, hence can be used in a specific well section to achieve temperature response. With phase change materials, precise cooling in a depth near a downhole device such as RSD and LWD can be achieved, and phase change materials are thus becoming the research hotspot in drilling fluid cooling technology. Presently phase change materials though have been widely used in photothermal storage of solar energy, building temperature regulation as well as heat management for electronic devices etc., their use in deep and ultra-deep well drilling and exploration is still in an initial exploration stage. This paper focuses on the classification of phase change materials, the research status of medium and high temperature phase change materials, the properties of phase change materials required for use in drilling fluids, as well as the existing literatures on application studies of drilling fluid cooling. In the future, cost effective phase change materials of high thermal conductivity can be developed through numerical simulation and field test. By strengthening multifunction design of these phase change materials, optimizing their compatibility with drilling fluids, and investigating environmentally friendly, highly efficient, stable and intelligent new phase change materials with multiple functions such as cooling, lubricating and reservoir protection etc., an innovative solution to drilling fluid technology can be developed.
2025, 42(5): 575-586.
doi: 10.12358/j.issn.1001-5620.2025.05.002
Abstract:
Subsalt oil and gas resources are abundant worldwide, with significant reserves located in the deepwater offshore regions of Brazil. The Mero field is a typical example of deepwater subsalt oil and gas resources, located in the southeastern Santos Basin offshore Brazil. The reservoir depth exceeds 5000 meters, with an overlying salt gypsum layer ranging from 150 to 3000 meters. The subsalt reservoirs are primarily composed of Lower Cretaceous BVE and ITP carbonate rocks. The Mero3 block in the Mero field experiences the most severe lost circulation, with a total loss of 17,105 m3. Through geological and drilling data analysis, the main causes of lost circulation were identified, including the development of faults and natural fractures, weak formation layers, and the strong heterogeneity of the formation. These factors collectively result in poor pressure-bearing capacity of the sealing layer, leading to repeated lost circulation incidents. This study collected commonly used plugging materials in the Mero field and conducted performance evaluation experiments on particle size distribution, friction coefficient, compressive strength, and compatibility. A database of plugging material performance parameters was established, and high-performance plugging materials suitable for deepwater subsalt reservoir loss prevention and plugging operations were selected. Based on different loss rates, three loss prevention formulas were designed using efficient bridging and dense filling methods, and the application process for these formulas was refined. Furthermore, a strategy for fine-tuning drilling techniques and maintaining a combination of loss prevention and plugging was proposed. This strategy includes strengthening the precise control of the wellbore ECD in loss-prone formations, reducing downhole overpressure, and minimizing the occurrence of induced fractures. The research results achieved significant success in the field plugging operations at the NW8 well of the Mero3 block. In cases with varying loss rates, the plugging strategy effectively slowed down the loss rate. This provides valuable technical support for the oil and gas development of Brazil's Mero field and other similar subsalt reservoirs, promoting the safe and efficient extraction of oil and gas resources.
Subsalt oil and gas resources are abundant worldwide, with significant reserves located in the deepwater offshore regions of Brazil. The Mero field is a typical example of deepwater subsalt oil and gas resources, located in the southeastern Santos Basin offshore Brazil. The reservoir depth exceeds 5000 meters, with an overlying salt gypsum layer ranging from 150 to 3000 meters. The subsalt reservoirs are primarily composed of Lower Cretaceous BVE and ITP carbonate rocks. The Mero3 block in the Mero field experiences the most severe lost circulation, with a total loss of 17,105 m3. Through geological and drilling data analysis, the main causes of lost circulation were identified, including the development of faults and natural fractures, weak formation layers, and the strong heterogeneity of the formation. These factors collectively result in poor pressure-bearing capacity of the sealing layer, leading to repeated lost circulation incidents. This study collected commonly used plugging materials in the Mero field and conducted performance evaluation experiments on particle size distribution, friction coefficient, compressive strength, and compatibility. A database of plugging material performance parameters was established, and high-performance plugging materials suitable for deepwater subsalt reservoir loss prevention and plugging operations were selected. Based on different loss rates, three loss prevention formulas were designed using efficient bridging and dense filling methods, and the application process for these formulas was refined. Furthermore, a strategy for fine-tuning drilling techniques and maintaining a combination of loss prevention and plugging was proposed. This strategy includes strengthening the precise control of the wellbore ECD in loss-prone formations, reducing downhole overpressure, and minimizing the occurrence of induced fractures. The research results achieved significant success in the field plugging operations at the NW8 well of the Mero3 block. In cases with varying loss rates, the plugging strategy effectively slowed down the loss rate. This provides valuable technical support for the oil and gas development of Brazil's Mero field and other similar subsalt reservoirs, promoting the safe and efficient extraction of oil and gas resources.
2025, 42(5): 587-593.
doi: 10.12358/j.issn.1001-5620.2025.05.003
Abstract:
The direction in which the properties of the self-adaptable high pressure bearing plugging agent are specifically optimized is understood by analyzing the lost circulation scenarios occurring in shallow extended-reach well drilling in Bohai area, that is, the formations penetrated by the wells have high heterogeneity as well as pores and fractures that are randomly distributed, and lost circulation materials have to effectively plug the pores and fractures with unknown sizes to stop mud losses. The formations penetrated have microfractures that are extremely developed and low pressure bearing capacities, and lost circulation materials must have high compressive strengths. To overcome these difficulties, an oil-absorbing self-adaptable high-pressure bearing plugging agent OBR-1 was synthesized with methyl methacrylate as the backbone and other monounsaturated fatty acid esters with different of carbon chain lengths. Experimental results show that OBR-1 has high volume expansion capacity at rubbery state, high elastic modulus after absorbing oils, good broad-spectrum plugging effect and high pressure bearing capacity. Sand disks of 10-120 μm plugged by a synthetic-based emulsion containing 2%OBR-1 have pressure bearing capacity of 10 MPa. A synthetic-based drilling fluid formulated with OBR-1 as the core material can plug 20-80 mesh sand-beds with pressure bearing capacities of 20 MPa, proving that OBR-1 has excellent pressure bearing capacity and plugging performance, and can provide guarantee for the safe and efficient drilling of offshore extended-reach wells.
The direction in which the properties of the self-adaptable high pressure bearing plugging agent are specifically optimized is understood by analyzing the lost circulation scenarios occurring in shallow extended-reach well drilling in Bohai area, that is, the formations penetrated by the wells have high heterogeneity as well as pores and fractures that are randomly distributed, and lost circulation materials have to effectively plug the pores and fractures with unknown sizes to stop mud losses. The formations penetrated have microfractures that are extremely developed and low pressure bearing capacities, and lost circulation materials must have high compressive strengths. To overcome these difficulties, an oil-absorbing self-adaptable high-pressure bearing plugging agent OBR-1 was synthesized with methyl methacrylate as the backbone and other monounsaturated fatty acid esters with different of carbon chain lengths. Experimental results show that OBR-1 has high volume expansion capacity at rubbery state, high elastic modulus after absorbing oils, good broad-spectrum plugging effect and high pressure bearing capacity. Sand disks of 10-120 μm plugged by a synthetic-based emulsion containing 2%OBR-1 have pressure bearing capacity of 10 MPa. A synthetic-based drilling fluid formulated with OBR-1 as the core material can plug 20-80 mesh sand-beds with pressure bearing capacities of 20 MPa, proving that OBR-1 has excellent pressure bearing capacity and plugging performance, and can provide guarantee for the safe and efficient drilling of offshore extended-reach wells.
Drilling Fluid Technology for Test Well with Ultra-Long Horizontal Section in Shale Oil Block Gulong
2025, 42(5): 594-599.
doi: 10.12358/j.issn.1001-5620.2025.05.004
Abstract:
With the development of the “Daqing Gulong Continental Shale Oil National Demonstration Zone”, wells with ultra-long horizontal sections are drilled to evaluate the correlation between the length of the horizontal section and the oil and gas production rate of a well. The length of the horizontal section is planned to be extended from the present 2000-2500 m to 3000-3500 m. Based on the formation characteristics of the Gulong shale oil block, drilling problems such as borehole wall stability, drag and friction reduction and borehole cleaning etc. that are probably encountered in drilling the ultra-long horizontal section wells were analyzed; the oil-based drilling fluid BH-OBM was optimized for those properties such as density, oil/water ratio and plugging performance, etc. During drilling, a “low viscosity high gel strength” rheology strategy and high drilling parameters were used to ensure hole cleaning and low friction and drag. The drilling operation of the test well GY2-Q9-H47 was successful: the average percent hole enlargement of the Φ215.9 mm was only 3.61% (based on wireline logging data), no borehole wall instability was encountered during drilling, and two new records in the shale gas oil block were set: the deepest well (5526 m) and the longest horizontal section (3123 m).
With the development of the “Daqing Gulong Continental Shale Oil National Demonstration Zone”, wells with ultra-long horizontal sections are drilled to evaluate the correlation between the length of the horizontal section and the oil and gas production rate of a well. The length of the horizontal section is planned to be extended from the present 2000-2500 m to 3000-3500 m. Based on the formation characteristics of the Gulong shale oil block, drilling problems such as borehole wall stability, drag and friction reduction and borehole cleaning etc. that are probably encountered in drilling the ultra-long horizontal section wells were analyzed; the oil-based drilling fluid BH-OBM was optimized for those properties such as density, oil/water ratio and plugging performance, etc. During drilling, a “low viscosity high gel strength” rheology strategy and high drilling parameters were used to ensure hole cleaning and low friction and drag. The drilling operation of the test well GY2-Q9-H47 was successful: the average percent hole enlargement of the Φ215.9 mm was only 3.61% (based on wireline logging data), no borehole wall instability was encountered during drilling, and two new records in the shale gas oil block were set: the deepest well (5526 m) and the longest horizontal section (3123 m).
2025, 42(5): 600-608.
doi: 10.12358/j.issn.1001-5620.2025.05.005
Abstract:
To understand the mechanisms of borehole wall instability of the easy-to-collapse formations in the southern margin of the Junggar Basin, mudstone cores were taken from the formation and studied through physio-chemical experiment, mechanical experiment and construction of a dynamic formation failure model. The results of the studies show that the mudstones in the southern margin of the basin contain 42% swelling clay minerals, the rate of swelling of the mudstone cores in contact with water is 30% or higher, and the percent recovery of the cores in hot rolling test is lower than 20%, indicating that the mudstone is quite easy to hydrate in water. The strength of the in-situ mudstones is lower than 40 MPa. After hydration, the strength and elastic modulus of the in-situ mudstones decrease exponentially, and the decreasing speed is fast at first, and then becomes slowly. As temperatures increase, the formation strength shows a trend of decrease, the speed of which is becoming faster. The cause of this phenomenon is “expand with heat and contract with cold”. The air in the pores of the formation expands, causing a change in the internal stresses of the rock, thereby reducing its strength. A multifield coupling dynamic borehole wall stabilization model was constructed to more accurately calculate the collapse pressure equivalent densities under different well angles, azimuths and action times. The results of the calculation help reveal the multifield coupling borehole wall instability mechanism of the mudstone formations in the southern margin of the Junggar Basin, and provide a theoretical guidance for maintaining wellbore stability during drilling and for drilling design.
To understand the mechanisms of borehole wall instability of the easy-to-collapse formations in the southern margin of the Junggar Basin, mudstone cores were taken from the formation and studied through physio-chemical experiment, mechanical experiment and construction of a dynamic formation failure model. The results of the studies show that the mudstones in the southern margin of the basin contain 42% swelling clay minerals, the rate of swelling of the mudstone cores in contact with water is 30% or higher, and the percent recovery of the cores in hot rolling test is lower than 20%, indicating that the mudstone is quite easy to hydrate in water. The strength of the in-situ mudstones is lower than 40 MPa. After hydration, the strength and elastic modulus of the in-situ mudstones decrease exponentially, and the decreasing speed is fast at first, and then becomes slowly. As temperatures increase, the formation strength shows a trend of decrease, the speed of which is becoming faster. The cause of this phenomenon is “expand with heat and contract with cold”. The air in the pores of the formation expands, causing a change in the internal stresses of the rock, thereby reducing its strength. A multifield coupling dynamic borehole wall stabilization model was constructed to more accurately calculate the collapse pressure equivalent densities under different well angles, azimuths and action times. The results of the calculation help reveal the multifield coupling borehole wall instability mechanism of the mudstone formations in the southern margin of the Junggar Basin, and provide a theoretical guidance for maintaining wellbore stability during drilling and for drilling design.
2025, 42(5): 609-616.
doi: 10.12358/j.issn.1001-5620.2025.05.006
Abstract:
Aiming at the problems such as low success rate of plugging and insufficient pressure bearing capacity of plugging layer caused by non-bonding force interaction between particles of conventional bridging materials, this paper developed a thermoplastic thermosensitive bonding resin plugging agent using acrylonitrile-styryl-butadiene copolymer as matrix resin and modified by blending maleic anhydride and petroleum resin. The properties of thermoplastic thermo-adhesive resin were characterized by infrared, thermogravimetric, DMA and high temperature and high pressure plugging instruments. The bonding mechanism of thermoplastic resin was analyzed. The results show that the plugging agent has good bonding and plugging performance at high temperature, and the pressure bearing capacity is as high as 8.2 MPa at 180℃. The thermosensitive adhesive resin is granular at room temperature and semi-molten solid after reaching the activation temperature. After entering the crack, it can self-adhesive plug through molecular chain diffusion and entanglement, so as to realize the thermosensitive, adaptive and efficient plugging function. Under high temperature conditions, thermoplastic resin thermosensitive adhesive resin can effectively improve the success rate of one-time plugging and pressure plugging ability, which provides a new theoretical and technical way to solve the problem of lost circulation during drilling.
Aiming at the problems such as low success rate of plugging and insufficient pressure bearing capacity of plugging layer caused by non-bonding force interaction between particles of conventional bridging materials, this paper developed a thermoplastic thermosensitive bonding resin plugging agent using acrylonitrile-styryl-butadiene copolymer as matrix resin and modified by blending maleic anhydride and petroleum resin. The properties of thermoplastic thermo-adhesive resin were characterized by infrared, thermogravimetric, DMA and high temperature and high pressure plugging instruments. The bonding mechanism of thermoplastic resin was analyzed. The results show that the plugging agent has good bonding and plugging performance at high temperature, and the pressure bearing capacity is as high as 8.2 MPa at 180℃. The thermosensitive adhesive resin is granular at room temperature and semi-molten solid after reaching the activation temperature. After entering the crack, it can self-adhesive plug through molecular chain diffusion and entanglement, so as to realize the thermosensitive, adaptive and efficient plugging function. Under high temperature conditions, thermoplastic resin thermosensitive adhesive resin can effectively improve the success rate of one-time plugging and pressure plugging ability, which provides a new theoretical and technical way to solve the problem of lost circulation during drilling.
2025, 42(5): 617-622.
doi: 10.12358/j.issn.1001-5620.2025.05.007
Abstract:
Drilling fluid additives with both high temperature stability and environment protection ability are the key to “safe, efficient, economic and green” well drilling. A high temperature environmentally friendly starch-based composite filter loss reducer was developed with a water-soluble starch, a fine walnut shell powder and an environmentally friendly acrylic acid resin. The synthesis is completed through inverse emulsion polymerization with the help of a crosslinking agent. This composite filter loss reducer has a maximum thermal decomposition temperature of 286℃, and has fibrous structure of irregular shapes and different sizes. After hot rolling at 220℃, a 4% bentonite base slurry treated with 2% composite filter loss reducer has its API filter loss reduced from 39 mL to 12 mL, and its HTHP filter loss from 172 mL to 52 mL, a rate of filtration reduction of nearly 70%. At elevated temperatures, the composite filter loss reducer shows a low viscosity filter loss control effect. Zeta potential analysis, particle size distribution measurement and SEM observation show that the molecules of the composite filter loss reducer can be adsorbed on the clay particles, thereby enhancing the colloidal stability and optimizing the particle sizing of the bentonite slurry. Meanwhile, the composite filter loss reducer can plug the pores formed in the mud cakes, making the mud cakes thin and tough, and based on these mechanisms, the high temperature filtration rate of the drilling fluid is finally significantly reduced. The results of this study provide a guidance to the research and development of ultra-high temperature environmentally friendly water-based drilling fluids.
Drilling fluid additives with both high temperature stability and environment protection ability are the key to “safe, efficient, economic and green” well drilling. A high temperature environmentally friendly starch-based composite filter loss reducer was developed with a water-soluble starch, a fine walnut shell powder and an environmentally friendly acrylic acid resin. The synthesis is completed through inverse emulsion polymerization with the help of a crosslinking agent. This composite filter loss reducer has a maximum thermal decomposition temperature of 286℃, and has fibrous structure of irregular shapes and different sizes. After hot rolling at 220℃, a 4% bentonite base slurry treated with 2% composite filter loss reducer has its API filter loss reduced from 39 mL to 12 mL, and its HTHP filter loss from 172 mL to 52 mL, a rate of filtration reduction of nearly 70%. At elevated temperatures, the composite filter loss reducer shows a low viscosity filter loss control effect. Zeta potential analysis, particle size distribution measurement and SEM observation show that the molecules of the composite filter loss reducer can be adsorbed on the clay particles, thereby enhancing the colloidal stability and optimizing the particle sizing of the bentonite slurry. Meanwhile, the composite filter loss reducer can plug the pores formed in the mud cakes, making the mud cakes thin and tough, and based on these mechanisms, the high temperature filtration rate of the drilling fluid is finally significantly reduced. The results of this study provide a guidance to the research and development of ultra-high temperature environmentally friendly water-based drilling fluids.
2025, 42(5): 623-630.
doi: 10.12358/j.issn.1001-5620.2025.05.008
Abstract:
Recycled old oil-based drilling fluids generally contain high concentrations of detrimental solids which result in performance deterioration of the drilling fluids. These detrimental solids can be removed through flocculation. In this study, an oil-based drilling fluid flocculant XN-1 was characterized for its performance in flocculating detrimental drilled solids, the flocculation mechanism of XN-1 was investigated, and the effectiveness of removing drilled solids and optimizing the properties of the oil-based drilling fluids through a combination of flocculation, screening and centrifugation was evaluated. Laboratory study and field experiment show that XN-1 has a good flocculating action in the old oil-based drilling fluid: the sizes of the flocs increase from submicron to 60 μm. After flocculation and screening, about 20% of the detrimental drilled solids are removed from the drilling fluid. After flocculation and centrifugation, 70.50% of the detrimental solids can be removed from the drilling fluid. The old mud, with the detrimental solids being removed, can be used to formulate new muds with significantly optimized properties. The application of the flocculant XN-1 effectively improves the reuse of old oil-based drilling fluids, realizes the effective recycling of old oil-based drilling fluids and greatly reduces of amount of hazardous and waste drilling fluids, and effectively solves the difficulty of removing detrimental solids from oil-based drilling fluids.
Recycled old oil-based drilling fluids generally contain high concentrations of detrimental solids which result in performance deterioration of the drilling fluids. These detrimental solids can be removed through flocculation. In this study, an oil-based drilling fluid flocculant XN-1 was characterized for its performance in flocculating detrimental drilled solids, the flocculation mechanism of XN-1 was investigated, and the effectiveness of removing drilled solids and optimizing the properties of the oil-based drilling fluids through a combination of flocculation, screening and centrifugation was evaluated. Laboratory study and field experiment show that XN-1 has a good flocculating action in the old oil-based drilling fluid: the sizes of the flocs increase from submicron to 60 μm. After flocculation and screening, about 20% of the detrimental drilled solids are removed from the drilling fluid. After flocculation and centrifugation, 70.50% of the detrimental solids can be removed from the drilling fluid. The old mud, with the detrimental solids being removed, can be used to formulate new muds with significantly optimized properties. The application of the flocculant XN-1 effectively improves the reuse of old oil-based drilling fluids, realizes the effective recycling of old oil-based drilling fluids and greatly reduces of amount of hazardous and waste drilling fluids, and effectively solves the difficulty of removing detrimental solids from oil-based drilling fluids.
2025, 42(5): 631-639.
doi: 10.12358/j.issn.1001-5620.2025.05.009
Abstract:
The proved undeveloped shale oil reserves in block Qibei of Dagang oilfield are still very high and their burial depths can be 4,500 m or deeper. This oil and gas enrichment area is located in the Shahejie reservoir which has high content of clays as well as developed interlayer pores and microfractures. Past experiences show that borehole wall instability and difficulties in tripping of drill strings have been encountered. To deal with these problems, three pilot test wells were drilled first in this area with oil-based drilling fluids. In laboratory studies an oil-based drilling fluid was formulated with 2% nanolatex, 2% sized calcium carbonate and 2% oxidized asphalt. Sizing of the particles rendered the drilling fluid high plugging capacity. In field application, the filtration rate of this drilling fluid through 750 mD sand-disks was reduced to 0.8 mL because the particles in the drilling fluid plugged the formation, minimizing the volume of the filtrates into the formations. In this way the wellbore stability was improved. The well QY6-31-2 was drilled in 40.98 d, refreshing PetroChina’s shortest drilling time record of wells with depths raging in 6501-7000 m, and setting 5 records in Dagang oilfield, such as the deepest completed well (6558 m) of horizontal shale oil wells. The use of oil-based drilling fluid has ensured the smooth construction of the pilot test wells.
The proved undeveloped shale oil reserves in block Qibei of Dagang oilfield are still very high and their burial depths can be 4,500 m or deeper. This oil and gas enrichment area is located in the Shahejie reservoir which has high content of clays as well as developed interlayer pores and microfractures. Past experiences show that borehole wall instability and difficulties in tripping of drill strings have been encountered. To deal with these problems, three pilot test wells were drilled first in this area with oil-based drilling fluids. In laboratory studies an oil-based drilling fluid was formulated with 2% nanolatex, 2% sized calcium carbonate and 2% oxidized asphalt. Sizing of the particles rendered the drilling fluid high plugging capacity. In field application, the filtration rate of this drilling fluid through 750 mD sand-disks was reduced to 0.8 mL because the particles in the drilling fluid plugged the formation, minimizing the volume of the filtrates into the formations. In this way the wellbore stability was improved. The well QY6-31-2 was drilled in 40.98 d, refreshing PetroChina’s shortest drilling time record of wells with depths raging in 6501-7000 m, and setting 5 records in Dagang oilfield, such as the deepest completed well (6558 m) of horizontal shale oil wells. The use of oil-based drilling fluid has ensured the smooth construction of the pilot test wells.
2025, 42(5): 640-645.
doi: 10.12358/j.issn.1001-5620.2025.05.010
Abstract:
Most of the traditional drilling fluid lubricity testers only consider the interaction between the interfaces of metals, and omit the effects of the adhesiveness between the drilling tools and drilling fluid, mud cakes and borehole walls on the lubricity of the drilling fluid, causing an inconformity between the evaluation results and the actual field performance of a lubricant. By simulating the interaction between the drilling tool and the borehole wall, the drilling tool and the drilling fluid as well as the drilling tool and the mud cake, a drilling fluid’s dynamic adhesiveness tester was developed. Experimental results show that the drilling fluid’s dynamic adhesiveness tester is easy to operate, and can be used to evaluate torque fluctuations under different pressures and rotational speeds. The results of the evaluation with this tester are accurate and highly repeatable, and can be used to effectively prevent stuck pipe accidents from occurring.
Most of the traditional drilling fluid lubricity testers only consider the interaction between the interfaces of metals, and omit the effects of the adhesiveness between the drilling tools and drilling fluid, mud cakes and borehole walls on the lubricity of the drilling fluid, causing an inconformity between the evaluation results and the actual field performance of a lubricant. By simulating the interaction between the drilling tool and the borehole wall, the drilling tool and the drilling fluid as well as the drilling tool and the mud cake, a drilling fluid’s dynamic adhesiveness tester was developed. Experimental results show that the drilling fluid’s dynamic adhesiveness tester is easy to operate, and can be used to evaluate torque fluctuations under different pressures and rotational speeds. The results of the evaluation with this tester are accurate and highly repeatable, and can be used to effectively prevent stuck pipe accidents from occurring.
2016, 33(1): 6-10.
doi: 10.3969/j.issn.1001-5620.2016.01.002
摘要：
以妥尔油脂肪酸和马来酸酐为主要原料合成了一种油基钻井液抗高温主乳化剂HT-MUL,并确定了妥尔油脂肪酸单体的最佳酸值及马来酸酐单体的最优加量。对HT-MUL进行了单剂评价,结果表明HT-MUL的乳化能力良好,配制的油水比为60:40的油包水乳液的破乳电压最高可达490 V,90:10的乳液破乳电压最高可达1000 V。从抗温性、滤失性、乳化率方面对HT-MUL和国内外同类产品进行了对比,结果表明HT-MUL配制的乳液破乳电压更大、滤失量更小、乳化率更高,整体性能优于国内外同类产品。应用主乳化剂HT-MUL配制了高密度的油基钻井液,其性能评价表明体系的基本性能良好,在220℃高温热滚后、破乳电压高达800 V,滤失量低于5 mL。HT-MUL配制的油基钻井液具有良好的抗高温性和乳化稳定性。
以妥尔油脂肪酸和马来酸酐为主要原料合成了一种油基钻井液抗高温主乳化剂HT-MUL,并确定了妥尔油脂肪酸单体的最佳酸值及马来酸酐单体的最优加量。对HT-MUL进行了单剂评价,结果表明HT-MUL的乳化能力良好,配制的油水比为60:40的油包水乳液的破乳电压最高可达490 V,90:10的乳液破乳电压最高可达1000 V。从抗温性、滤失性、乳化率方面对HT-MUL和国内外同类产品进行了对比,结果表明HT-MUL配制的乳液破乳电压更大、滤失量更小、乳化率更高,整体性能优于国内外同类产品。应用主乳化剂HT-MUL配制了高密度的油基钻井液,其性能评价表明体系的基本性能良好,在220℃高温热滚后、破乳电压高达800 V,滤失量低于5 mL。HT-MUL配制的油基钻井液具有良好的抗高温性和乳化稳定性。
2016, 33(5): 1-8.
doi: 10.3969/j.issn.1001-5620.2016.05.001
摘要：
综述了国内外页岩气井井壁失稳机理、稳定井壁主要方法及水基钻井液技术研究与应用现状，讨论了当前中国页岩气井钻井液技术面临的主要技术难题，分析了美国页岩气井与中国主要页岩气产区井壁失稳机理的差异，指出了中国页岩气井水基钻井液技术研究存在的误区与不足，提出了中国页岩气井水基钻井液技术发展方向。
综述了国内外页岩气井井壁失稳机理、稳定井壁主要方法及水基钻井液技术研究与应用现状，讨论了当前中国页岩气井钻井液技术面临的主要技术难题，分析了美国页岩气井与中国主要页岩气产区井壁失稳机理的差异，指出了中国页岩气井水基钻井液技术研究存在的误区与不足，提出了中国页岩气井水基钻井液技术发展方向。
2018, 35(2): 1-16.
doi: 10.3969/j.issn.1001-5620.2018.02.001
摘要：
通常在勘探开发油气过程中会发生不同程度的油气层损害，导致产量下降、甚至"枪毙"油气层等，钻井液是第一个与油气层相接触的外来流体，引起的油气层损害程度往往较大。为减轻或避免钻井液导致的油气层损害、提高单井产量，国内外学者们进行了长达半个世纪以上的研究工作，先后建立了"屏蔽暂堵、精细暂堵、物理化学膜暂堵"三代暂堵型保护油气层钻井液技术，使保护油气层效果逐步提高，经济效益明显。但是，与石油工程师们追求的"超低"损害目标仍存在一定差距，特别是随着非常规、复杂、超深层、超深水等类型油气层勘探开发力度的加大，以前的保护技术难以满足要求。为此，将仿生学引入保护油气层钻井液理论中，发展了适合不同油气层渗透率大小的"超双疏、生物膜、协同增效"仿生技术，并在各大油田得到推广应用，达到了"超低"损害目标，标志着第四代暂堵型保护油气层钻井液技术的建立。对上述4代暂堵型保护油气层技术的理论基础、实施方案、室内评价、现场应用效果与优缺点等进行了论述，并通过梳理阐明了将来的研究方向与发展趋势，对现场技术人员和科技工作者具有较大指导意义。
通常在勘探开发油气过程中会发生不同程度的油气层损害，导致产量下降、甚至"枪毙"油气层等，钻井液是第一个与油气层相接触的外来流体，引起的油气层损害程度往往较大。为减轻或避免钻井液导致的油气层损害、提高单井产量，国内外学者们进行了长达半个世纪以上的研究工作，先后建立了"屏蔽暂堵、精细暂堵、物理化学膜暂堵"三代暂堵型保护油气层钻井液技术，使保护油气层效果逐步提高，经济效益明显。但是，与石油工程师们追求的"超低"损害目标仍存在一定差距，特别是随着非常规、复杂、超深层、超深水等类型油气层勘探开发力度的加大，以前的保护技术难以满足要求。为此，将仿生学引入保护油气层钻井液理论中，发展了适合不同油气层渗透率大小的"超双疏、生物膜、协同增效"仿生技术，并在各大油田得到推广应用，达到了"超低"损害目标，标志着第四代暂堵型保护油气层钻井液技术的建立。对上述4代暂堵型保护油气层技术的理论基础、实施方案、室内评价、现场应用效果与优缺点等进行了论述，并通过梳理阐明了将来的研究方向与发展趋势，对现场技术人员和科技工作者具有较大指导意义。
2016, 33(1): 33-36.
doi: 10.3969/j.issn.1001-5620.2016.01.007
摘要：
页岩具有极低的渗透率和极小的孔喉尺寸,传统封堵剂难以在页岩表面形成有效的泥饼,只有纳米级颗粒才能封堵页岩的孔喉,阻止液相侵入地层,维持井壁稳定,保护储层。以苯乙烯(St)、甲基丙烯酸甲酯(MMA)为单体,过硫酸钾(KPS)为引发剂,采用乳液聚合法制备了纳米聚合物微球封堵剂SD-seal。通过红外光谱、透射电镜、热重分析和激光粒度分析对产物进行了表征,通过龙马溪组岩样的压力传递实验研究了其封堵性能。结果表明,SD-seal纳米粒子分散性好,形状规则(基本为球形),粒度较均匀(20 nm左右),分解温度高达402.5℃,热稳定性好,阻缓压力传递效果显著,使龙马溪组页岩岩心渗透率降低95%。
页岩具有极低的渗透率和极小的孔喉尺寸,传统封堵剂难以在页岩表面形成有效的泥饼,只有纳米级颗粒才能封堵页岩的孔喉,阻止液相侵入地层,维持井壁稳定,保护储层。以苯乙烯(St)、甲基丙烯酸甲酯(MMA)为单体,过硫酸钾(KPS)为引发剂,采用乳液聚合法制备了纳米聚合物微球封堵剂SD-seal。通过红外光谱、透射电镜、热重分析和激光粒度分析对产物进行了表征,通过龙马溪组岩样的压力传递实验研究了其封堵性能。结果表明,SD-seal纳米粒子分散性好,形状规则(基本为球形),粒度较均匀(20 nm左右),分解温度高达402.5℃,热稳定性好,阻缓压力传递效果显著,使龙马溪组页岩岩心渗透率降低95%。
2016, 33(4): 74-78.
doi: 10.3969/j.issn.1001-5620.2016.04.015
摘要：
利用自主研发的水泥环密封性实验装置研究了套管内加卸压循环作用下水泥环的密封性，根据实验结果得出了循环应力作用下水泥环密封性失效的机理。实验结果显示，在较低套管内压循环作用下，水泥环保持密封性所能承受的应力循环次数较多；在较高循环应力作用下，水泥环密封性失效时循环次数较少。表明在套管内较低压力作用下，水泥环所受的应力较低，应力水平处于弹性状态，在加卸载的循环作用下，水泥环可随之弹性变形和弹性恢复；在较高应力作用下，水泥环内部固有的微裂纹和缺陷逐渐扩展和连通，除了发生弹性变形还产生了塑性变形；随着应力循环次数的增加，塑性变形也不断地累积。循环压力卸载时，套管弹性回缩而水泥环塑性变形不可完全恢复，2者在界面处的变形不协调而引起拉应力。当拉应力超过界面处的胶结强度时出现微环隙，导致水泥环密封性失效，水泥环发生循环应力作用的低周期密封性疲劳破坏。套管内压力越大，水泥环中产生的应力水平越高，产生的塑性变形越大，每次卸载时产生的残余应变和界面处拉应力也越大，因此引起密封性失效的应力循环次数越少。
利用自主研发的水泥环密封性实验装置研究了套管内加卸压循环作用下水泥环的密封性，根据实验结果得出了循环应力作用下水泥环密封性失效的机理。实验结果显示，在较低套管内压循环作用下，水泥环保持密封性所能承受的应力循环次数较多；在较高循环应力作用下，水泥环密封性失效时循环次数较少。表明在套管内较低压力作用下，水泥环所受的应力较低，应力水平处于弹性状态，在加卸载的循环作用下，水泥环可随之弹性变形和弹性恢复；在较高应力作用下，水泥环内部固有的微裂纹和缺陷逐渐扩展和连通，除了发生弹性变形还产生了塑性变形；随着应力循环次数的增加，塑性变形也不断地累积。循环压力卸载时，套管弹性回缩而水泥环塑性变形不可完全恢复，2者在界面处的变形不协调而引起拉应力。当拉应力超过界面处的胶结强度时出现微环隙，导致水泥环密封性失效，水泥环发生循环应力作用的低周期密封性疲劳破坏。套管内压力越大，水泥环中产生的应力水平越高，产生的塑性变形越大，每次卸载时产生的残余应变和界面处拉应力也越大，因此引起密封性失效的应力循环次数越少。
2017, 34(1): 1-8.
doi: 10.3969/j.issn.1001-5620.2017.01.001
摘要：
分析了硬脆性泥页岩井壁失稳的原因，介绍了纳米材料特点及其应用，并概述了国内外钻井液用纳米封堵剂的研究进展，包括有机纳米封堵剂、无机纳米封堵剂、有机/无机纳米封堵剂，以及纳米封堵剂现场应用案例。笔者认为：利用无机纳米材料刚性特征以及有机聚合物可任意变形、支化成膜等特性，形成的一种核壳结构的无机/聚合物类纳米封堵剂，能够很好地分散到钻井液中，且对钻井液黏度和切力影响较小，这种类型的纳米封堵剂能够在低浓度下封堵泥页岩孔喉，建立一种疏水型且具有一定强度的泥页岩人工井壁，这不仅能够阻止钻井液侵入，而且还能提高地层承压能力，无机纳米材料与有机聚合物的结合是未来钻井液防塌剂的发展方向。
分析了硬脆性泥页岩井壁失稳的原因，介绍了纳米材料特点及其应用，并概述了国内外钻井液用纳米封堵剂的研究进展，包括有机纳米封堵剂、无机纳米封堵剂、有机/无机纳米封堵剂，以及纳米封堵剂现场应用案例。笔者认为：利用无机纳米材料刚性特征以及有机聚合物可任意变形、支化成膜等特性，形成的一种核壳结构的无机/聚合物类纳米封堵剂，能够很好地分散到钻井液中，且对钻井液黏度和切力影响较小，这种类型的纳米封堵剂能够在低浓度下封堵泥页岩孔喉，建立一种疏水型且具有一定强度的泥页岩人工井壁，这不仅能够阻止钻井液侵入，而且还能提高地层承压能力，无机纳米材料与有机聚合物的结合是未来钻井液防塌剂的发展方向。
2016, 33(6): 121-126.
doi: 10.3969/j.issn.1001-5620.2016.06.022
摘要：
统计长庆油田罗*区块2015年存地液量与油井一年累积产量的关系发现，存地液量越大，一年累积产量越高，与常规的返排率越高产量越高概念恰恰相反，可能与存地液的自发渗吸替油有关。核磁实验结果表明，渗吸替油不同于驱替作用，渗吸过程中小孔隙对采出程度贡献大，而驱替过程中大孔隙对采出程度贡献大，但从现场致密储层岩心孔隙度来看，储层驱替效果明显弱于渗吸效果。通过实验研究了影响自发渗吸效率因素，探索影响压裂液油水置换的关键影响因素，得出了最佳渗吸采出率及最大渗吸速度现场参数。结果表明，各参数对渗吸速度的影响顺序为：界面张力 > 渗透率 > 原油黏度 > 矿化度,岩心渗透率越大，渗吸采收率越大，但是增幅逐渐减小；原油黏度越小，渗吸采收率越大；渗吸液矿化度越大，渗吸采收率越大；当渗吸液中助排剂浓度在0.005%~5%，即界面张力在0.316~10.815 mN/m范围内时，浓度为0.5%（界面张力为0.869 mN/m）的渗吸液可以使渗吸采收率达到最大。静态渗吸结果表明：并不是界面张力越低，采收率越高，而是存在某一最佳界面张力，使地层中被绕流油的数量减少，渗吸采收率达到最高，为油田提高致密储层采收率提供实验指导。
统计长庆油田罗*区块2015年存地液量与油井一年累积产量的关系发现，存地液量越大，一年累积产量越高，与常规的返排率越高产量越高概念恰恰相反，可能与存地液的自发渗吸替油有关。核磁实验结果表明，渗吸替油不同于驱替作用，渗吸过程中小孔隙对采出程度贡献大，而驱替过程中大孔隙对采出程度贡献大，但从现场致密储层岩心孔隙度来看，储层驱替效果明显弱于渗吸效果。通过实验研究了影响自发渗吸效率因素，探索影响压裂液油水置换的关键影响因素，得出了最佳渗吸采出率及最大渗吸速度现场参数。结果表明，各参数对渗吸速度的影响顺序为：界面张力 > 渗透率 > 原油黏度 > 矿化度,岩心渗透率越大，渗吸采收率越大，但是增幅逐渐减小；原油黏度越小，渗吸采收率越大；渗吸液矿化度越大，渗吸采收率越大；当渗吸液中助排剂浓度在0.005%~5%，即界面张力在0.316~10.815 mN/m范围内时，浓度为0.5%（界面张力为0.869 mN/m）的渗吸液可以使渗吸采收率达到最大。静态渗吸结果表明：并不是界面张力越低，采收率越高，而是存在某一最佳界面张力，使地层中被绕流油的数量减少，渗吸采收率达到最高，为油田提高致密储层采收率提供实验指导。
2016, 33(1): 17-21.
doi: 10.3969/j.issn.1001-5620.2016.01.004
摘要：
目前中国页岩气水平井定向段及水平段钻井均使用油基钻井液,但油基岩屑处理费用昂贵,急需开发和应用一种具有环境保护特性的高性能水基钻井液体系。介绍了2种高性能水基钻井液体系的室内实验和现场试验效果。在长宁H9-4井水平段、长宁H9-3和长宁H9-5井定向至完井段试验了GOF高性能水基钻井液体系,该体系采用的是聚合物封堵抑制方案,完全采用水基润滑方式;在昭通区块YS108H4-2井水平段试验了高润强抑制性水基钻井液体系,该体系采用的是有机、无机盐复合防膨方案以及润滑剂与柴油复合润滑方式。现场应用表明,定向段机械钻速提高50%~75%,水平段机械钻速提高75%~100%。通过实验数据及现场使用情况,对比分析了2种体系的优劣,找出了他们各自存在的问题,并提出了改进的思路,为高性能水基钻井液的进一步完善提供一些经验。
目前中国页岩气水平井定向段及水平段钻井均使用油基钻井液,但油基岩屑处理费用昂贵,急需开发和应用一种具有环境保护特性的高性能水基钻井液体系。介绍了2种高性能水基钻井液体系的室内实验和现场试验效果。在长宁H9-4井水平段、长宁H9-3和长宁H9-5井定向至完井段试验了GOF高性能水基钻井液体系,该体系采用的是聚合物封堵抑制方案,完全采用水基润滑方式;在昭通区块YS108H4-2井水平段试验了高润强抑制性水基钻井液体系,该体系采用的是有机、无机盐复合防膨方案以及润滑剂与柴油复合润滑方式。现场应用表明,定向段机械钻速提高50%~75%,水平段机械钻速提高75%~100%。通过实验数据及现场使用情况,对比分析了2种体系的优劣,找出了他们各自存在的问题,并提出了改进的思路,为高性能水基钻井液的进一步完善提供一些经验。
2016, 33(3): 25-29.
doi: 10.3969/j.issn.1001-5620.2016.03.005
摘要：
页岩气井水平井段井壁失稳是目前中国页岩气资源勘探开发的关键技术难题。通过云南昭通108区块龙马溪组页岩的X-射线衍射分析、扫描电镜（SEM）观察、力学特性分析、润湿性、膨胀率及回收率等实验，研究了其矿物组成、微观组构特征、表面性能、膨胀和分散特性，揭示了云南昭通108区块龙马溪组页岩地层井壁水化失稳机理。该地层黏土矿物以伊利石为主要组分，不含蒙脱石及伊蒙混层，表面水化是引起页岩地层井壁失稳的主要原因。基于热力学第二定律，利用降低页岩表面自由能以抑制页岩表面水化的原理，建立了通过多碳醇吸附作用改变页岩润湿性，有效降低其表面自由能、抑制表面水化，进而显著抑制页岩水化膨胀和分散的稳定井壁方法。
页岩气井水平井段井壁失稳是目前中国页岩气资源勘探开发的关键技术难题。通过云南昭通108区块龙马溪组页岩的X-射线衍射分析、扫描电镜（SEM）观察、力学特性分析、润湿性、膨胀率及回收率等实验，研究了其矿物组成、微观组构特征、表面性能、膨胀和分散特性，揭示了云南昭通108区块龙马溪组页岩地层井壁水化失稳机理。该地层黏土矿物以伊利石为主要组分，不含蒙脱石及伊蒙混层，表面水化是引起页岩地层井壁失稳的主要原因。基于热力学第二定律，利用降低页岩表面自由能以抑制页岩表面水化的原理，建立了通过多碳醇吸附作用改变页岩润湿性，有效降低其表面自由能、抑制表面水化，进而显著抑制页岩水化膨胀和分散的稳定井壁方法。
2018, 35(3): 8-16.
doi: 10.3969/j.issn.1001-5620.2018.03.002
摘要：
解决环境污染问题是改善钻井液的关键，开发环保型抗高温降滤失剂是当前研究的重要领域之一。概述了国内外环保型降滤失剂的研究进展，对国内外在环保型降滤失剂研制中所使用的原材料及产品性能，以及中国抗温改性天然高分子降滤失剂的发展近况进行了介绍。天然高分子降滤失剂是通过对淀粉、纤维素及木质素等天然高分子材料进行改性以提高其抗温、抗盐能力，使其可以应用于井温更高的深井钻探中。目前，中国环保型降滤失剂普遍可以应用到150℃的高温中，部分抗温能力可达到180℃却未能推广使用。通过对现有降滤失剂的研究，分析其抗高温的作用机理，探寻能有效提高抗温能力的单体分子结构及发挥作用的功能基团，例如磺酸基团、内酰胺基团等，以期对环保型抗高温降滤失剂的研制起到一定的指导和参考作用，加快环保型抗高温降滤失剂的发展。
解决环境污染问题是改善钻井液的关键，开发环保型抗高温降滤失剂是当前研究的重要领域之一。概述了国内外环保型降滤失剂的研究进展，对国内外在环保型降滤失剂研制中所使用的原材料及产品性能，以及中国抗温改性天然高分子降滤失剂的发展近况进行了介绍。天然高分子降滤失剂是通过对淀粉、纤维素及木质素等天然高分子材料进行改性以提高其抗温、抗盐能力，使其可以应用于井温更高的深井钻探中。目前，中国环保型降滤失剂普遍可以应用到150℃的高温中，部分抗温能力可达到180℃却未能推广使用。通过对现有降滤失剂的研究，分析其抗高温的作用机理，探寻能有效提高抗温能力的单体分子结构及发挥作用的功能基团，例如磺酸基团、内酰胺基团等，以期对环保型抗高温降滤失剂的研制起到一定的指导和参考作用，加快环保型抗高温降滤失剂的发展。
2020, 37(6): 685-693.
doi: 10.3969/j.issn.1001-5620.2020.06.002
Abstract:
2016, 33(5): 1-8.
doi: 10.3969/j.issn.1001-5620.2016.05.001
Abstract:
2016, 33(6): 1-9.
doi: 10.3969/j.issn.1001-5620.2016.06.001
Abstract:
2017, 34(1): 1-8.
doi: 10.3969/j.issn.1001-5620.2017.01.001
Abstract:
2016, 33(6): 45-50.
doi: 10.3969/j.issn.1001-5620.2016.06.008
Abstract:
2016, 33(1): 6-10.
doi: 10.3969/j.issn.1001-5620.2016.01.002
Abstract:
2018, 35(1): 101-104.
doi: 10.3969/j.issn.1001-5620.2018.01.019
Abstract:
2018, 35(1): 34-37.
doi: 10.3969/j.issn.1001-5620.2018.01.006
Abstract:
2017, 34(1): 16-22.
doi: 10.3969/j.issn.1001-5620.2017.01.003
Abstract:
2016, 33(6): 10-16.
doi: 10.3969/j.issn.1001-5620.2016.06.002
Abstract:
Governed by：
China National Petroleum Corporation Ltd
China National Petroleum Corporation Ltd
Sponsored by：
CNPC Bohai Drilling Engineering Co. LtdPetroChina Huabei Oilfield Company
CNPC Bohai Drilling Engineering Co. LtdPetroChina Huabei Oilfield Company
Editor-in-Chief：Shi-chun Chen（Engineer Technology Research Institute,BHDC）
Deputy Editor-in-chief：
Gui-juan Wang（Engineer Technology Research Institute,BHDC）Qiang Ren（Engineer Technology Research Institute,BHDC）
Address：
Editorial Office of Drilling Fluid and Completion Fluid, Bohai Drilling Engineering Institute, Yanshan South Road, Renqiu City, Hebei Province
Editorial Office of Drilling Fluid and Completion Fluid, Bohai Drilling Engineering Institute, Yanshan South Road, Renqiu City, Hebei Province
Postcode： 062552
Tel：（0317）2725487 2722354
E-mail： zjyywjy@126.com
CN 12-1486/TE
ISSN 1001-5620
