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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 Plugging Micro-fractures to Prevent Gas-cut in Fractured Gas Reservoir Drilling
9 Development of Extreme Pressure Anti-wear Lubricant MPA for Water Base Drilling Fluids
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 Challenges, Developments, and Suggestions for Drilling Fluid Technology in China
6 Progresses in Studying Drilling Fluid Nano Material Plugging Agents
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(6): 705-712.
doi: 10.12358/j.issn.1001-5620.2025.06.001
Abstract:
The second member of Liushagang Formation in Weishan Sag, Beibuwan Basin, is oil shale with highly developed micro-fractures and high brittle mineral content. PLUS/KCl water-based drilling fluid was used in vertical well drilling in the early stage, resulting in serious wellbore instability and frequent blockage. The problems existing in the water-based and diesel-based drilling fluids used in the area were analyzed in the laboratory. Based on the formula of the on-site diesel-based drilling fluid, a set of high performance and low aromatics gas-to-oil drilling fluid system was constructed by introducing low viscosity and low aromatics gas-to-oil production and grading optimal micro-nano sealing agent materials. The system has a lower activity of 0.62, a high recovery rate of 98%, no leakage in 300 μm micro-crack plugging, a settlement factor less than 0.51, better inhibition and plugging, and stable high temperature performance. The gas-to-oil drilling fluid was applied in 8 highly inclined rock oil exploration wells, and the application well operation was smooth, and the diameter enlargement rate was less than 2%. Compared with the diesel-based drilling fluid system, the maximum funnel viscosity and plastic viscosity were reduced by 54% and 41% respectively, and the daily loss was reduced by 50%, and the comprehensive cost was reduced by about 85 million yuan. This technology provides powerful drilling fluid technical support for accelerating the development of offshore shale oil resources.
The second member of Liushagang Formation in Weishan Sag, Beibuwan Basin, is oil shale with highly developed micro-fractures and high brittle mineral content. PLUS/KCl water-based drilling fluid was used in vertical well drilling in the early stage, resulting in serious wellbore instability and frequent blockage. The problems existing in the water-based and diesel-based drilling fluids used in the area were analyzed in the laboratory. Based on the formula of the on-site diesel-based drilling fluid, a set of high performance and low aromatics gas-to-oil drilling fluid system was constructed by introducing low viscosity and low aromatics gas-to-oil production and grading optimal micro-nano sealing agent materials. The system has a lower activity of 0.62, a high recovery rate of 98%, no leakage in 300 μm micro-crack plugging, a settlement factor less than 0.51, better inhibition and plugging, and stable high temperature performance. The gas-to-oil drilling fluid was applied in 8 highly inclined rock oil exploration wells, and the application well operation was smooth, and the diameter enlargement rate was less than 2%. Compared with the diesel-based drilling fluid system, the maximum funnel viscosity and plastic viscosity were reduced by 54% and 41% respectively, and the daily loss was reduced by 50%, and the comprehensive cost was reduced by about 85 million yuan. This technology provides powerful drilling fluid technical support for accelerating the development of offshore shale oil resources.
2025, 42(6): 713-720.
doi: 10.12358/j.issn.1001-5620.2025.06.002
Abstract:
This study aims at finding a more environmentally friendly and efficient oil-based drilling fluid to reduce drilling costs, to minimize the negative effects of the drilling fluid on the environment, to enhance the safety and quality of drilling operation, and to provide a new green drilling fluid solution. It was well known that vegetable oil-based drilling fluids formulated with base fluids such as peanut oil, soybean oil and castor oil have low ecotoxicity, good lubricity and high inhibitive capacity in stabilizing clay formations, and can be used to replace diesel oil-based drilling fluid. In laboratory experiments a vegetable oil-based drilling fluid was formulated with modified cottonseed oil as the base fluid and other oil-based drilling fluid additives. Laboratory evaluation results showed that the vegetable oil-based drilling fluid has strong capacity in inhibiting clay hydration and swelling, good high temperature stability, strong salt and bentonite contamination resistance, as well as excellent reservoir protection performance. Two well-times of successful use of this drilling fluid in Tuha oilfield showed that the drilling fluid performed very well: it effectively stabilized the borehole wall against collapse, ensuring the optimal and fast drilling of the wells and the safety of the drilling operation. Oil-on-cuttings was tested for its toxicity and the results conformed to the relevant standards. The vegetable oil-based drilling fluid has properties equivalent to those of a diesel oil-based drilling fluid and can be used to replace traditional oil-based drilling fluids in the future.
This study aims at finding a more environmentally friendly and efficient oil-based drilling fluid to reduce drilling costs, to minimize the negative effects of the drilling fluid on the environment, to enhance the safety and quality of drilling operation, and to provide a new green drilling fluid solution. It was well known that vegetable oil-based drilling fluids formulated with base fluids such as peanut oil, soybean oil and castor oil have low ecotoxicity, good lubricity and high inhibitive capacity in stabilizing clay formations, and can be used to replace diesel oil-based drilling fluid. In laboratory experiments a vegetable oil-based drilling fluid was formulated with modified cottonseed oil as the base fluid and other oil-based drilling fluid additives. Laboratory evaluation results showed that the vegetable oil-based drilling fluid has strong capacity in inhibiting clay hydration and swelling, good high temperature stability, strong salt and bentonite contamination resistance, as well as excellent reservoir protection performance. Two well-times of successful use of this drilling fluid in Tuha oilfield showed that the drilling fluid performed very well: it effectively stabilized the borehole wall against collapse, ensuring the optimal and fast drilling of the wells and the safety of the drilling operation. Oil-on-cuttings was tested for its toxicity and the results conformed to the relevant standards. The vegetable oil-based drilling fluid has properties equivalent to those of a diesel oil-based drilling fluid and can be used to replace traditional oil-based drilling fluids in the future.
2025, 42(6): 721-727.
doi: 10.12358/j.issn.1001-5620.2025.06.003
Abstract:
A rheology modifier for non-aqueous based drilling fluids was prepared in this work. Based on the drilling fluid systems of China Oilfield Services Co., LTD., the influence of dosage, aging temperature and aging time on rheology and electrical stability performance of drilling fluid were studied. The anti-pollution ability were also studied in this work. The results showed the gel strength was obviously improved with the increasing dosage and weakened with the increasing aging time. It indicated that PF-MOVIS is gradually consumed during drilling process and it need to be added with a small number of times in the actual operation process. The temperature resistance of PF-MOVIS reached 170℃. It showed an obvious better gel strength under the temperature of 170℃ when adding the PF-MOVIS. Moreover, PF-MOVIS could obviously improve the electrical stability properties. It has excellent anti-pollution ability and reservoir protection performance. According to the pilot scale study, the performance of the pilot product was comparable to even better than that of the lab sample. At the same time, the field application results showed that PF-MOVIS obviously increased gel strength for non-aqueous based drilling fluids. The field application effect was very well and and it has great popularization value.
A rheology modifier for non-aqueous based drilling fluids was prepared in this work. Based on the drilling fluid systems of China Oilfield Services Co., LTD., the influence of dosage, aging temperature and aging time on rheology and electrical stability performance of drilling fluid were studied. The anti-pollution ability were also studied in this work. The results showed the gel strength was obviously improved with the increasing dosage and weakened with the increasing aging time. It indicated that PF-MOVIS is gradually consumed during drilling process and it need to be added with a small number of times in the actual operation process. The temperature resistance of PF-MOVIS reached 170℃. It showed an obvious better gel strength under the temperature of 170℃ when adding the PF-MOVIS. Moreover, PF-MOVIS could obviously improve the electrical stability properties. It has excellent anti-pollution ability and reservoir protection performance. According to the pilot scale study, the performance of the pilot product was comparable to even better than that of the lab sample. At the same time, the field application results showed that PF-MOVIS obviously increased gel strength for non-aqueous based drilling fluids. The field application effect was very well and and it has great popularization value.
2025, 42(6): 728-737.
doi: 10.12358/j.issn.1001-5620.2025.06.004
Abstract:
Oil-based drilling and completion fluids presently in use have poor suspension stability at high temperatures up to 240℃ or higher. To deal with this problem, a strongly hydrophobic suspension stabilizer HPAS was developed based on the principle of strengthening the stability of a colloidal system through spatial grid structure. HPAS was synthesized using sepiolite fiber and n-octyltriethoxysilane as the raw materials. The final product was obtained by treating the intermediate product with hydrochloric acid and then organic modification. Characterization of HPAS with IR, TGA, particle size analysis and surface wettability proved that the modification is successful. A high-density oil-based drilling fluid was formulated with HPAS. After aging at 260℃, the properties of the drilling fluid were still good, the AV and PV of the drilling fluid were about 33 mPa·s and 27 mPa·s, respectively, the YP of the drilling fluid was at least 4 Pa, the electric stability was higher than 800 V, the HTHP filter loss was kept under 5 mL, and the thickness of the mud cake was less than 2 mm. Evaluation of the sedimentation stability of the drilling fluid showed that after standing at 240℃ for 7 d there was no hard sedimentation found, and a glass rod can freely drop through the drilling fluid to the bottom of the mud container. Moreover, the YP of the drilling fluid remained at more than 4.5 MPa at temperatures between 65℃ and 240℃ and pressures between atmospheric pressure and 190 MPa, indicating that the drilling fluid can maintain good suspension stability and solids carrying performance under these conditions. The development of this drilling fluid provides a technical support for the use of oil-based drilling and completion fluids in drilling deep, ultra-deep wells and even wells of ten thousand meters in depths.
Oil-based drilling and completion fluids presently in use have poor suspension stability at high temperatures up to 240℃ or higher. To deal with this problem, a strongly hydrophobic suspension stabilizer HPAS was developed based on the principle of strengthening the stability of a colloidal system through spatial grid structure. HPAS was synthesized using sepiolite fiber and n-octyltriethoxysilane as the raw materials. The final product was obtained by treating the intermediate product with hydrochloric acid and then organic modification. Characterization of HPAS with IR, TGA, particle size analysis and surface wettability proved that the modification is successful. A high-density oil-based drilling fluid was formulated with HPAS. After aging at 260℃, the properties of the drilling fluid were still good, the AV and PV of the drilling fluid were about 33 mPa·s and 27 mPa·s, respectively, the YP of the drilling fluid was at least 4 Pa, the electric stability was higher than 800 V, the HTHP filter loss was kept under 5 mL, and the thickness of the mud cake was less than 2 mm. Evaluation of the sedimentation stability of the drilling fluid showed that after standing at 240℃ for 7 d there was no hard sedimentation found, and a glass rod can freely drop through the drilling fluid to the bottom of the mud container. Moreover, the YP of the drilling fluid remained at more than 4.5 MPa at temperatures between 65℃ and 240℃ and pressures between atmospheric pressure and 190 MPa, indicating that the drilling fluid can maintain good suspension stability and solids carrying performance under these conditions. The development of this drilling fluid provides a technical support for the use of oil-based drilling and completion fluids in drilling deep, ultra-deep wells and even wells of ten thousand meters in depths.
2025, 42(6): 738-747.
doi: 10.12358/j.issn.1001-5620.2025.06.005
Abstract:
A nanocellulose filter loss reducer CNF-ADDS was developed through aqueous solution graft polymerization. Laboratory experiments were conducted on it to analyze its effects on the rheology and filtration property of drilling fluids, to evaluate its high temperature performance and salt and calcium resistance capacities, and to reveal its filtration reduction mechanism. Experimental results show that the average length of the CNF-ADDS molecules is about 300 nm. Treatment of the base mud of a water-based drilling fluid with 2%CNF-ADDS increases its apparent viscosity to 32 mPa·s and the plastic viscosity to 22 mPa·s. After aging at 260℃, the HTHP filter loss tested at 150℃ is only 16.3 mL. After contamination by 36%NaCl and 3%CaCl2 respectively, the CNF-ADDS-treated drilling fluids were then aged at 260℃, the HTHP filter losses of the drilling fluids tested at 150℃ were 17.4 mL and 16.5 mL, respectively, and the mud cakes were tough and thin. By self-assembling into a network structure, the CNF-ADDS molecules can be adsorbed onto the surfaces of the clay particles, thereby reducing the filter loss of the drilling fluid in high temperature and high salinity (NaCl and CaCl2) environment.
A nanocellulose filter loss reducer CNF-ADDS was developed through aqueous solution graft polymerization. Laboratory experiments were conducted on it to analyze its effects on the rheology and filtration property of drilling fluids, to evaluate its high temperature performance and salt and calcium resistance capacities, and to reveal its filtration reduction mechanism. Experimental results show that the average length of the CNF-ADDS molecules is about 300 nm. Treatment of the base mud of a water-based drilling fluid with 2%CNF-ADDS increases its apparent viscosity to 32 mPa·s and the plastic viscosity to 22 mPa·s. After aging at 260℃, the HTHP filter loss tested at 150℃ is only 16.3 mL. After contamination by 36%NaCl and 3%CaCl2 respectively, the CNF-ADDS-treated drilling fluids were then aged at 260℃, the HTHP filter losses of the drilling fluids tested at 150℃ were 17.4 mL and 16.5 mL, respectively, and the mud cakes were tough and thin. By self-assembling into a network structure, the CNF-ADDS molecules can be adsorbed onto the surfaces of the clay particles, thereby reducing the filter loss of the drilling fluid in high temperature and high salinity (NaCl and CaCl2) environment.
2025, 42(6): 748-755.
doi: 10.12358/j.issn.1001-5620.2025.06.006
Abstract:
In high temperature reservoir operations, oil/gas cut causes drilling accidents such as well kick and even well blowout. Conventional polymer gels, though can be used to prevent gas channeling from occurring, have poor high temperature resistance. In this study, a high temperature gas-kick preventer was prepared using a high temperature polymer AP-9, a crosslinking agent (polyethyleneimine and aluminum citrate in a ratio of 1∶1) and thiourea. Laboratory experiments were conducted to find the effect of the concentration of each component on the thermostability of the high temperature gas-kick preventer. As a result of the experiments, an optimal composition was determined as: 0.5%AP-9+0.4% crosslinking agent+0.25% thiourea. Laboratory evaluation results show that at 160℃ a gel formulated with 25 000 mg/L Na+ saltwater and the high temperature gas-kick preventer has viscosity of 7120 mPa·s after gelling, indicating that the high temperature gas-kick preventer has good salt resistance. After heating for 72 h, the viscosity of the saltwater gel still reaches 3328 mPa·s, and the pressure bearing strength of the saltwater gel is 0.23 MPa/m. The results of this study provide a technical support for effectively preventing gas kick in a high temperature well, they are helpful for achieving whole-process underbalanced drilling, and are of great importance to improving the safety and efficiency of drilling operation.
In high temperature reservoir operations, oil/gas cut causes drilling accidents such as well kick and even well blowout. Conventional polymer gels, though can be used to prevent gas channeling from occurring, have poor high temperature resistance. In this study, a high temperature gas-kick preventer was prepared using a high temperature polymer AP-9, a crosslinking agent (polyethyleneimine and aluminum citrate in a ratio of 1∶1) and thiourea. Laboratory experiments were conducted to find the effect of the concentration of each component on the thermostability of the high temperature gas-kick preventer. As a result of the experiments, an optimal composition was determined as: 0.5%AP-9+0.4% crosslinking agent+0.25% thiourea. Laboratory evaluation results show that at 160℃ a gel formulated with 25 000 mg/L Na+ saltwater and the high temperature gas-kick preventer has viscosity of 7120 mPa·s after gelling, indicating that the high temperature gas-kick preventer has good salt resistance. After heating for 72 h, the viscosity of the saltwater gel still reaches 3328 mPa·s, and the pressure bearing strength of the saltwater gel is 0.23 MPa/m. The results of this study provide a technical support for effectively preventing gas kick in a high temperature well, they are helpful for achieving whole-process underbalanced drilling, and are of great importance to improving the safety and efficiency of drilling operation.
2025, 42(6): 756-763.
doi: 10.12358/j.issn.1001-5620.2025.06.007
Abstract:
Gel plugging agents usually have the characteristic of good adaptiveness, but the existing drilling fluid gel plugging agents generally suffer from poor stability at elevated temperatures and poor strength. To deal with these problems, a drilling fluid plugging agent was developed by the hybridization of high temperature carbon nanotubes and a terpolymer; the terpolymer gel is used as the matrix and the carbon nanotubes (CNTs) are used as the rigid nanoparticles to aim to solve the problems such as borehole wall instability resulted from the failure of the plugging agents at elevated temperatures in deep well drilling. A nanofiber plugging agent was synthesized by radical polymerization based on a molecular structure design in which maleic anhydride (MAH), alkenyl succinic anhydride (ASA) and styrene (St) were selected as the copolymerization monomers, benzoyl peroxide (BPO) as the initiator, and N, N-methylenebisacrylamide (MBA) as the crosslinking agent. The synthesized high temperature hybridized carbon nanotubes and terpolymer gel plugging agent was evaluated for its functional structures and plugging performance by transmission electron microscopy and sand-disc plugging experiment. The results of the evaluation show that, a drilling fluid treated with 1.0% of the synthesized product has the optimal plugging capacity. At 150℃, the drilling fluid has good rheological properties, good filtration control effect, and can effectively plug nano-micron sized pores and fractures.
Gel plugging agents usually have the characteristic of good adaptiveness, but the existing drilling fluid gel plugging agents generally suffer from poor stability at elevated temperatures and poor strength. To deal with these problems, a drilling fluid plugging agent was developed by the hybridization of high temperature carbon nanotubes and a terpolymer; the terpolymer gel is used as the matrix and the carbon nanotubes (CNTs) are used as the rigid nanoparticles to aim to solve the problems such as borehole wall instability resulted from the failure of the plugging agents at elevated temperatures in deep well drilling. A nanofiber plugging agent was synthesized by radical polymerization based on a molecular structure design in which maleic anhydride (MAH), alkenyl succinic anhydride (ASA) and styrene (St) were selected as the copolymerization monomers, benzoyl peroxide (BPO) as the initiator, and N, N-methylenebisacrylamide (MBA) as the crosslinking agent. The synthesized high temperature hybridized carbon nanotubes and terpolymer gel plugging agent was evaluated for its functional structures and plugging performance by transmission electron microscopy and sand-disc plugging experiment. The results of the evaluation show that, a drilling fluid treated with 1.0% of the synthesized product has the optimal plugging capacity. At 150℃, the drilling fluid has good rheological properties, good filtration control effect, and can effectively plug nano-micron sized pores and fractures.
2025, 42(6): 764-771.
doi: 10.12358/j.issn.1001-5620.2025.06.008
Abstract:
Lost circulation in reservoir drilling has been encountered in deep coalbed methane drilling in the east of Junggar Basin (Xinjiang) because the reservoir formations have insufficient pressure bearing capacity. Based on the characteristics of the lost circulation encountered, the mineral composition of the reservoir formations was analyzed and the morphology of the formations observed using SEM. The mechanisms of lost circulation were determined to be the extension of fractures and the connection of pores in the formations, and a countermeasure for overcoming the lost circulation problem was presented as the synergistic application of “plugging agent + filtration agent + shale inhibitor”. Based on the “reduce costs and increase efficiency” principle, the concentrations of the key drilling fluid additives were optimized. The key additives were then formulated through orthogonal experiment with the basic slurry to form four lost circulation prevention drilling fluids. The four drilling fluids were then tested for their performance in permeability recovery and based on the results, a drilling fluid with the best reservoir protection was determined. Experimental results show that this drilling fluid has stable rheology, the percent permeability recovery can be as high as 87.42%, the API and HTHP filtration rates are 4.16 mL and 9.52 mL, respectively, the filtration rate on sand-bed test is less than 15 mL, indicating that the drilling fluid has good plugging capacity. In inhibitive capacity experiments, the rate of swelling of drilled cuttings tested with the filtrate of the drilling fluid is only 0.96%, and the percent cuttings recovery in hot rolling test with the drilling fluid is as high as 91.6%, indicating that the drilling fluid has excellent inhibitive capacity. In field application of the optimized drilling fluid, lost circulation was mitigated, drilling time shortened, complex working conditions minimized, and reservoirs were protected more effectively. The use of the optimized drilling fluid has provided an important technical support and application reference to safe and efficient drilling of deep coalbed methane.
Lost circulation in reservoir drilling has been encountered in deep coalbed methane drilling in the east of Junggar Basin (Xinjiang) because the reservoir formations have insufficient pressure bearing capacity. Based on the characteristics of the lost circulation encountered, the mineral composition of the reservoir formations was analyzed and the morphology of the formations observed using SEM. The mechanisms of lost circulation were determined to be the extension of fractures and the connection of pores in the formations, and a countermeasure for overcoming the lost circulation problem was presented as the synergistic application of “plugging agent + filtration agent + shale inhibitor”. Based on the “reduce costs and increase efficiency” principle, the concentrations of the key drilling fluid additives were optimized. The key additives were then formulated through orthogonal experiment with the basic slurry to form four lost circulation prevention drilling fluids. The four drilling fluids were then tested for their performance in permeability recovery and based on the results, a drilling fluid with the best reservoir protection was determined. Experimental results show that this drilling fluid has stable rheology, the percent permeability recovery can be as high as 87.42%, the API and HTHP filtration rates are 4.16 mL and 9.52 mL, respectively, the filtration rate on sand-bed test is less than 15 mL, indicating that the drilling fluid has good plugging capacity. In inhibitive capacity experiments, the rate of swelling of drilled cuttings tested with the filtrate of the drilling fluid is only 0.96%, and the percent cuttings recovery in hot rolling test with the drilling fluid is as high as 91.6%, indicating that the drilling fluid has excellent inhibitive capacity. In field application of the optimized drilling fluid, lost circulation was mitigated, drilling time shortened, complex working conditions minimized, and reservoirs were protected more effectively. The use of the optimized drilling fluid has provided an important technical support and application reference to safe and efficient drilling of deep coalbed methane.
2025, 42(6): 772-780.
doi: 10.12358/j.issn.1001-5620.2025.06.009
Abstract:
Lost circulation is one of the key factors restricting drilling safety and efficiency. To realize accurate prediction of lost circulation, a hybrid model for the prediction of lost circulation is presented based on long short-term memory (LSTM) and random forest (RF) algorithm. The LSTM model, the RF model and the LSTM-RF hybrid model are constructed based on algorithm principle. Fourteen lost circulation characteristic parameters are selected using correlation analysis method, and are input into three lost circulation prediction models for training. The performance and lost circulation prediction accuracy of the three models are then analyzed and compared. The experimental results show that the root mean square error (RMSE) of the hybrid model on the test dataset is 0.11, the mean absolute error (MAE) is 0.22, the coefficient of determination (R2) is 0.95, and the overall accuracy reaches 84.2%, each indicator is better than that of the single model. Furthermore, hybrid model has successfully predicted 5 times of lost circulation in field application. The results of this study show that LSTM-RF hybrid model is a model with optimal comprehensive performance in lost circulation prediction, it can predict lost circulation more precisely, and can provide reference for the prevention of lost circulation and for the decision making in drilling operation.
Lost circulation is one of the key factors restricting drilling safety and efficiency. To realize accurate prediction of lost circulation, a hybrid model for the prediction of lost circulation is presented based on long short-term memory (LSTM) and random forest (RF) algorithm. The LSTM model, the RF model and the LSTM-RF hybrid model are constructed based on algorithm principle. Fourteen lost circulation characteristic parameters are selected using correlation analysis method, and are input into three lost circulation prediction models for training. The performance and lost circulation prediction accuracy of the three models are then analyzed and compared. The experimental results show that the root mean square error (RMSE) of the hybrid model on the test dataset is 0.11, the mean absolute error (MAE) is 0.22, the coefficient of determination (R2) is 0.95, and the overall accuracy reaches 84.2%, each indicator is better than that of the single model. Furthermore, hybrid model has successfully predicted 5 times of lost circulation in field application. The results of this study show that LSTM-RF hybrid model is a model with optimal comprehensive performance in lost circulation prediction, it can predict lost circulation more precisely, and can provide reference for the prevention of lost circulation and for the decision making in drilling operation.
2025, 42(6): 781-787.
doi: 10.12358/j.issn.1001-5620.2025.06.010
Abstract:
In geothermal energy development, the heat loss of cement sheath plays a key role in affecting heat extraction efficiency. In this study, using class G cement as the base slurry, and hollow glass microspheres and modified palygorskite fiber as composite low thermal conductivity material, a low thermal conductivity cement slurry was formulated through composition optimization. Laboratory experiments on the rheology, stability, thermal conductivity and compressive strength of the cement slurry were all tested. It was found that compared with conventional cement slurries, the thermal conductivity of this cement slurry is reduced by 74.4%, and the 7-d compressive strength of this cement slurry is 19.7 MPa. The use of the low thermal conductivity agents in this cement slurry makes the pores inside the set cement finer and more evenly distributed. This not only reduces the thermal conductivity of the cement; it also improves the mechanical performance and durability of the cement. This technology can be used to reduce the heat loss and enhance the efficiency of geothermal extraction.
In geothermal energy development, the heat loss of cement sheath plays a key role in affecting heat extraction efficiency. In this study, using class G cement as the base slurry, and hollow glass microspheres and modified palygorskite fiber as composite low thermal conductivity material, a low thermal conductivity cement slurry was formulated through composition optimization. Laboratory experiments on the rheology, stability, thermal conductivity and compressive strength of the cement slurry were all tested. It was found that compared with conventional cement slurries, the thermal conductivity of this cement slurry is reduced by 74.4%, and the 7-d compressive strength of this cement slurry is 19.7 MPa. The use of the low thermal conductivity agents in this cement slurry makes the pores inside the set cement finer and more evenly distributed. This not only reduces the thermal conductivity of the cement; it also improves the mechanical performance and durability of the cement. This technology can be used to reduce the heat loss and enhance the efficiency of geothermal extraction.
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。
2020, 37(1): 1-8.
doi: 10.3969/j.issn.1001-5620.2020.01.001
摘要：
废弃钻井液污染大、种类多、处理难，给水质和土壤环境带来巨大的负面影响，随着近些年环保法规的日益完善，对废弃钻井液的处理技术也提出了新要求。概述了9种不同处理方法及其发展现状，重点分析了固化法、热解吸法、化学强化固液分离法、不落地技术和多种技术联用等处理技术，并对几种现行的主流处理技术进行了对比，指出了各类方法的发展前景，得出多种技术联用具有较好的发展潜力。分析认为今后的研究方向与热点在于如何低能耗、高效率地实现对废弃钻井液的资源化处理，具体工作既要包含污染物的源头、过程和结果控制，也要加强管理和相关制度的建立，综合开发新技术。
废弃钻井液污染大、种类多、处理难，给水质和土壤环境带来巨大的负面影响，随着近些年环保法规的日益完善，对废弃钻井液的处理技术也提出了新要求。概述了9种不同处理方法及其发展现状，重点分析了固化法、热解吸法、化学强化固液分离法、不落地技术和多种技术联用等处理技术，并对几种现行的主流处理技术进行了对比，指出了各类方法的发展前景，得出多种技术联用具有较好的发展潜力。分析认为今后的研究方向与热点在于如何低能耗、高效率地实现对废弃钻井液的资源化处理，具体工作既要包含污染物的源头、过程和结果控制，也要加强管理和相关制度的建立，综合开发新技术。
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。
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。
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:
2017, 34(1): 16-22.
doi: 10.3969/j.issn.1001-5620.2017.01.003
Abstract:
2018, 35(1): 34-37.
doi: 10.3969/j.issn.1001-5620.2018.01.006
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：
Room A517, China Petroleum Tianjin Building, No. 83, Second Avenue, Tianjin Economic and Technological Development Zone
Room A517, China Petroleum Tianjin Building, No. 83, Second Avenue, Tianjin Economic and Technological Development Zone
Postcode： 300457
Tel：022-65278734022-25275527
E-mail： zjyywjy@126.com
CN 12-1486/TE
ISSN 1001-5620
