2013 Vol. 33 No. 4
Abstract：
As an important hydrocarbon reservoir, reefs have great potential in oil exploration. Qiongdongnan basin is located in the northern continental margin of South China Sea, with favorable environment for reef growth and carbonate development during the evolution process. The south deepwater area of Qiongdongnan Basin is far away from the provenance, and many structural highs have developed, which was favorable for reef development. Through seismic data interpretation, it is believed that different scale reefs have developed in the southern deepwater area of Qiongdongnan Basin. In addition, these reefs have great hydrocarbon potential, and the development reefs can be correlated well with the tectonic evolutionary stages.
As an important hydrocarbon reservoir, reefs have great potential in oil exploration. Qiongdongnan basin is located in the northern continental margin of South China Sea, with favorable environment for reef growth and carbonate development during the evolution process. The south deepwater area of Qiongdongnan Basin is far away from the provenance, and many structural highs have developed, which was favorable for reef development. Through seismic data interpretation, it is believed that different scale reefs have developed in the southern deepwater area of Qiongdongnan Basin. In addition, these reefs have great hydrocarbon potential, and the development reefs can be correlated well with the tectonic evolutionary stages.
Abstract：
Delta facies oilfields in Paleogene Dongying Formation of Bohai Bay are the main oil-bearing series. In this paper, the geological characteristics of delta facies oilfields of main Dongying Formation in Bohai Bay have been studied, focus mainly on structure, stratigraphy, sedimentation, fluid and reservoir characteristics. The reservoir description on the distribution characteristics of fluvial delta facies and braided river delta sandstone facies reservoirs have been conducted. Based on the study results, the fluid distribution characteristics and reservoir modes of such oilfields have been discussed. It is believed through study that most of the delta facies oilfields are large scale reservoirs, and the reservoir lithology is mainly unconsolidated sandstone, with high porosity and high permeability. The reservoirs are characterized by steady distribution, relative large thickness and good physical properties. The oils are mainly heavy oil, and secondly medium and low viscosity oils.
Delta facies oilfields in Paleogene Dongying Formation of Bohai Bay are the main oil-bearing series. In this paper, the geological characteristics of delta facies oilfields of main Dongying Formation in Bohai Bay have been studied, focus mainly on structure, stratigraphy, sedimentation, fluid and reservoir characteristics. The reservoir description on the distribution characteristics of fluvial delta facies and braided river delta sandstone facies reservoirs have been conducted. Based on the study results, the fluid distribution characteristics and reservoir modes of such oilfields have been discussed. It is believed through study that most of the delta facies oilfields are large scale reservoirs, and the reservoir lithology is mainly unconsolidated sandstone, with high porosity and high permeability. The reservoirs are characterized by steady distribution, relative large thickness and good physical properties. The oils are mainly heavy oil, and secondly medium and low viscosity oils.
Abstract：
The discovery of high porosity and high permeability reservoirs has changed the traditional understanding about reservoir quality in E3s2 in A structural area, Bohai Sea. On the basis of the drilling core and the laboratory analyzing results, study has been conducted on the lithologic characteristics, sedimentary genesis, reservoir characteristics and influence factors on this type of reservoir. The study results indicate that this type of reservoir was mixed deposits, affected by intermittent local terrigenous supply, and the sedimentary facies is the main factor influencing the reservoir quality. In addition, the later mixed dolomitization has some positive influence on reservoir quality protection and improvement.
The discovery of high porosity and high permeability reservoirs has changed the traditional understanding about reservoir quality in E3s2 in A structural area, Bohai Sea. On the basis of the drilling core and the laboratory analyzing results, study has been conducted on the lithologic characteristics, sedimentary genesis, reservoir characteristics and influence factors on this type of reservoir. The study results indicate that this type of reservoir was mixed deposits, affected by intermittent local terrigenous supply, and the sedimentary facies is the main factor influencing the reservoir quality. In addition, the later mixed dolomitization has some positive influence on reservoir quality protection and improvement.
Abstract：
Pinghu formation in Paleogene, consisting mainly of grayish green pebbly fine sandstone, was penetrated in A well in Xihu sag, East China Sea. Through analysis of trace elements, paleontological data, grain size characteristics and logging data, it is indicated that the content of boron is low, Sr/Ba ratio is less than 1, and Fe/Mn ration is far higher than 5, indicating that the sediments were deposited in fresh water. Meanwhile, the Ni/Co ratio is between 2.5 ~5 and the V/Ni ratio is higher than 1,indicating that sedimentary environment was reducing environment. In the sediments, spores are quite abundant, while the pollen of broad-leaved trees and warm/humid-preferring conifers dominates the pollen assemblages, that suggests the the regional climate was close to modern subtropical climate, it was warm and quite humid then. In the P formation of A well, the gravels are characterized by proximal and fast accumulation; the mudstones are relatively deep water deposits. The grain sizes have typical turbidite characteristic. Combined with the spatial distribution pattern of different rocks, it can be determinated that P formation is nearshore subsea fan sedimentary facies.
Pinghu formation in Paleogene, consisting mainly of grayish green pebbly fine sandstone, was penetrated in A well in Xihu sag, East China Sea. Through analysis of trace elements, paleontological data, grain size characteristics and logging data, it is indicated that the content of boron is low, Sr/Ba ratio is less than 1, and Fe/Mn ration is far higher than 5, indicating that the sediments were deposited in fresh water. Meanwhile, the Ni/Co ratio is between 2.5 ~5 and the V/Ni ratio is higher than 1,indicating that sedimentary environment was reducing environment. In the sediments, spores are quite abundant, while the pollen of broad-leaved trees and warm/humid-preferring conifers dominates the pollen assemblages, that suggests the the regional climate was close to modern subtropical climate, it was warm and quite humid then. In the P formation of A well, the gravels are characterized by proximal and fast accumulation; the mudstones are relatively deep water deposits. The grain sizes have typical turbidite characteristic. Combined with the spatial distribution pattern of different rocks, it can be determinated that P formation is nearshore subsea fan sedimentary facies.
Abstract：
Based on depositional environment analysis, study on diagenesis has been conducted systematically for the lower member of Xingouzui Formation of Paleogene in Mawangmiao area of Qianjiang Sag in Jianghan basin. The study results indicate that the lower member of Xingouzui Fm in Mawangmiao area was in arid and evaporated-oxidative model I sedimentary environment and half arid-humid climate, weak oxidative-weak reductive model II sedimentary environment. Accordingly, two types of reservoirs have been developed, two types of diagenesis have occurred, with quite different influence on reservoir quality due to the influence of formation water. Cementation is dominated in Model I diagenesis, with great damage to reservoir pores, and the better quality reservoirs were developed in fault zones. Model II diagenesis is dominated by chemical denudation, with positive effect on reservoir quality, and the reservoir properties are relatively good, being favorable for HC accumulation widely. This understanding provides a solid foundation for study of the diagenesis in this area, and also contribute to further exploration and development of this oil bearing area.
Based on depositional environment analysis, study on diagenesis has been conducted systematically for the lower member of Xingouzui Formation of Paleogene in Mawangmiao area of Qianjiang Sag in Jianghan basin. The study results indicate that the lower member of Xingouzui Fm in Mawangmiao area was in arid and evaporated-oxidative model I sedimentary environment and half arid-humid climate, weak oxidative-weak reductive model II sedimentary environment. Accordingly, two types of reservoirs have been developed, two types of diagenesis have occurred, with quite different influence on reservoir quality due to the influence of formation water. Cementation is dominated in Model I diagenesis, with great damage to reservoir pores, and the better quality reservoirs were developed in fault zones. Model II diagenesis is dominated by chemical denudation, with positive effect on reservoir quality, and the reservoir properties are relatively good, being favorable for HC accumulation widely. This understanding provides a solid foundation for study of the diagenesis in this area, and also contribute to further exploration and development of this oil bearing area.
Abstract：
Seismic forward modeling technique is used for simulation of seismic wave field in real geological structure conditions by means of mathematics or physical method through study of propagation characteristics of seismic wave in a simplifying model. In recent years, with the increasing in difficulty in oil and gas exploration, forward modeling technique has been used more and more widely. With seven areas in the northwestern margin of Junggar basin as an example, the application of forward modeling technique to seismic data interpretation is discussed. This technique has good results in geological pattern recognition, fine description of faults, analysis of abnormal velocity and small fault recognition.
Seismic forward modeling technique is used for simulation of seismic wave field in real geological structure conditions by means of mathematics or physical method through study of propagation characteristics of seismic wave in a simplifying model. In recent years, with the increasing in difficulty in oil and gas exploration, forward modeling technique has been used more and more widely. With seven areas in the northwestern margin of Junggar basin as an example, the application of forward modeling technique to seismic data interpretation is discussed. This technique has good results in geological pattern recognition, fine description of faults, analysis of abnormal velocity and small fault recognition.
Abstract：
To study the relationship between Nickel and Vanadium distribution characteristics with HC accumulation, statistic analysis has been conducted on the content of Nickel and Vanadium on the basis of core, core borings and crude oil data from Junggar Basin. The study results showed that the content of Nickel and Vanadium is the largest in mudstones, secondarily in sandstones, and very small in oil samples and oil-bearing sands (bitumen). In stratigraphy, the content of Nickel and Vanadium is the largest in Jurassic and Permian. Statistic analysis has also been conducted on the planar distribution of Nickel and Vanadium in the target Jurassic. The statistic analyzing results on the content of Nickel and Vanadium showed that the southeast part of Block A is favorable area for HC exploration, with low value of Nickel and Vanadium contents. The south part of Block F is also the favorable area for HC exploration, with low value of Nickel and Vanadium contents. When conducting well production testing in individual well, the content of Nickel and Vanadium is large at oil-water layers or oil bearing water layers, and small in pure oil layers, which indicated that water layers will increase the content of Nickel and Vanadium, and oil layers will decrease the content of Nickel and Vanadium. When conducting well production testing in individual well, the ratio of Nickel and Vanadium is 1 at pure water layers. Finally, it is pointed out that from A to G Blocks, the areas with low content of Nickel and Vanadium are favorable HC exploration areas in Junggar Basin.
To study the relationship between Nickel and Vanadium distribution characteristics with HC accumulation, statistic analysis has been conducted on the content of Nickel and Vanadium on the basis of core, core borings and crude oil data from Junggar Basin. The study results showed that the content of Nickel and Vanadium is the largest in mudstones, secondarily in sandstones, and very small in oil samples and oil-bearing sands (bitumen). In stratigraphy, the content of Nickel and Vanadium is the largest in Jurassic and Permian. Statistic analysis has also been conducted on the planar distribution of Nickel and Vanadium in the target Jurassic. The statistic analyzing results on the content of Nickel and Vanadium showed that the southeast part of Block A is favorable area for HC exploration, with low value of Nickel and Vanadium contents. The south part of Block F is also the favorable area for HC exploration, with low value of Nickel and Vanadium contents. When conducting well production testing in individual well, the content of Nickel and Vanadium is large at oil-water layers or oil bearing water layers, and small in pure oil layers, which indicated that water layers will increase the content of Nickel and Vanadium, and oil layers will decrease the content of Nickel and Vanadium. When conducting well production testing in individual well, the ratio of Nickel and Vanadium is 1 at pure water layers. Finally, it is pointed out that from A to G Blocks, the areas with low content of Nickel and Vanadium are favorable HC exploration areas in Junggar Basin.
Abstract：
Bohai SZ36-1 oilfield is viscous oilfield, with high density, high viscosity, high content of colloid and asphaltene. With traditional thermal well washing technology individually, a large number of geothermal water should be used for a long time to clean the wellbore, resulting in waste of resources and pollution of formation. Therefore, the chemical synergy thermal well-washing technology is put forward. Through laboratory research and numerous applications on offshore platforms, good results have been achieved, reducing the operation time and oil recovery cycle, and increasing oil production. This method can also be used for well flushing and paraffin removal in other viscous oilfield.
Bohai SZ36-1 oilfield is viscous oilfield, with high density, high viscosity, high content of colloid and asphaltene. With traditional thermal well washing technology individually, a large number of geothermal water should be used for a long time to clean the wellbore, resulting in waste of resources and pollution of formation. Therefore, the chemical synergy thermal well-washing technology is put forward. Through laboratory research and numerous applications on offshore platforms, good results have been achieved, reducing the operation time and oil recovery cycle, and increasing oil production. This method can also be used for well flushing and paraffin removal in other viscous oilfield.
2013, 33(4): 45-49.
DOI: 10.3969/j.issn.l008-2336.2013.04.052
Abstract：
Many problems often happen during workover in Bohai oilfield, such as that heavy leakage, difficult fishing, and slow washover footage. To overcome these problems, a new kind of environment friendly washover and sand cleaning fluid has been developed on the basis of foam drilling theory. Compared with the traditional temporary blocking solution, this kind of fluid is more preferable, with low viscosity, small shearing force, high sand-carrying capacity, low circular friction, easy to dissolve and no blocking pump. With this kind of fluid, it is not necessary to break the glue in the latter. The composition is 0.5%BH-VIS+3%FPJ-I2+3%XJW-0H-2%YS-A. With microbubble as dispersed phase, low viscosity glue solution as continuous phase, this kind of fluid has good effect in sand cleaning and fluid loss reducing due to the high sand holding capacity of foam as well as double plugging capacity of foam and biopolymer. This technology has been used successfully in Bohai oilfield, which is guarantee for smooth workover operation.
Many problems often happen during workover in Bohai oilfield, such as that heavy leakage, difficult fishing, and slow washover footage. To overcome these problems, a new kind of environment friendly washover and sand cleaning fluid has been developed on the basis of foam drilling theory. Compared with the traditional temporary blocking solution, this kind of fluid is more preferable, with low viscosity, small shearing force, high sand-carrying capacity, low circular friction, easy to dissolve and no blocking pump. With this kind of fluid, it is not necessary to break the glue in the latter. The composition is 0.5%BH-VIS+3%FPJ-I2+3%XJW-0H-2%YS-A. With microbubble as dispersed phase, low viscosity glue solution as continuous phase, this kind of fluid has good effect in sand cleaning and fluid loss reducing due to the high sand holding capacity of foam as well as double plugging capacity of foam and biopolymer. This technology has been used successfully in Bohai oilfield, which is guarantee for smooth workover operation.
Abstract：
Chemical flooding is suitable in Block 113-3 of Honggang Oilfield because the reservoirs in this field are characterized by thick layers, high average permeability and the serious interlayer heterogeneity. To meet the actual requirments for development of Block 113-3 of Honggang Oilfield, a series of experiments have been conducted to evaluate the viscosifying, salt tolerance, temperature and shear resistance, stability, rheological property and viscoelasticity characteristics of the compound polymers and common polymers. The study results indicated that comparing with the common polymer, the compound polymers are better in propreties of the viscosifying, salt tolerance, temperature and shear resistance, and the the distribution of the relative molecular mass is also wider. The compound polymers are better in compatibility with the reservoirs because the resistance factor and residual resistance factor are larger, and swept volume is also larger. Therefore, it is recommendated that compound polymer flooding should be used in Block 113-3 of Honggang Oilfield, and the optimizeding mass ratio of the compound polymer is 17:60:23 for ultrahigh molecule, macromolecule and medium molecule polymers.
Chemical flooding is suitable in Block 113-3 of Honggang Oilfield because the reservoirs in this field are characterized by thick layers, high average permeability and the serious interlayer heterogeneity. To meet the actual requirments for development of Block 113-3 of Honggang Oilfield, a series of experiments have been conducted to evaluate the viscosifying, salt tolerance, temperature and shear resistance, stability, rheological property and viscoelasticity characteristics of the compound polymers and common polymers. The study results indicated that comparing with the common polymer, the compound polymers are better in propreties of the viscosifying, salt tolerance, temperature and shear resistance, and the the distribution of the relative molecular mass is also wider. The compound polymers are better in compatibility with the reservoirs because the resistance factor and residual resistance factor are larger, and swept volume is also larger. Therefore, it is recommendated that compound polymer flooding should be used in Block 113-3 of Honggang Oilfield, and the optimizeding mass ratio of the compound polymer is 17:60:23 for ultrahigh molecule, macromolecule and medium molecule polymers.
2013, 33(4): 57-61,82.
DOI: 10.3969/j.issn.1008-2336.2013.04.057
Abstract：
The multi-functional ultrasonic imaging logging tool can be used for casing inspection and cement bonding evaluation by using ultrasonic pulse echo technique. The field data measured by the MUIL shows that the reflection wave will be firstly received by transducer and then is the resonance wave. The character of spectrum trap is visible obviously in frequency spectrum curve of waveform. The casing's internal conditions can be inspected from the echo amplitude and transit time. The casing thickness and the cement impedance can be calculated from the resonance frequency and resonance decay. It shows that this tool can evaluate the geologic feature information,such as fracture,vug and bedding structure in the opened-hole. Weather the component of material behind casing is gas, liquid or solid can be curtained based on the variable range of cement impedance. The measurement result shows that this tool has the function of borehole imaging, casing inspection and cement bonding evaluation.
The multi-functional ultrasonic imaging logging tool can be used for casing inspection and cement bonding evaluation by using ultrasonic pulse echo technique. The field data measured by the MUIL shows that the reflection wave will be firstly received by transducer and then is the resonance wave. The character of spectrum trap is visible obviously in frequency spectrum curve of waveform. The casing's internal conditions can be inspected from the echo amplitude and transit time. The casing thickness and the cement impedance can be calculated from the resonance frequency and resonance decay. It shows that this tool can evaluate the geologic feature information,such as fracture,vug and bedding structure in the opened-hole. Weather the component of material behind casing is gas, liquid or solid can be curtained based on the variable range of cement impedance. The measurement result shows that this tool has the function of borehole imaging, casing inspection and cement bonding evaluation.
Abstract：
The North Yellow Sea Basin is a new offshore oil and gas exploration area, with multiphase tectonic evolution, and the geological conditions are very complicated. Therefore, the HC exploration in this area is rather difficult. Based on acoustic-electric imaging logging data, analysis has been conducted on lithology, the types of bedding, fractures, palaeocurrent direction and in-situ formation stress orientation in the study area of the eastern depression of North Yellow Sea Basin, The study results indicated that the lithologies of Mesozoic in this area consists mainly sandy conglomerate, fine grained sandstones, siltstones and mudstones. Horizontal bedding is well developed in mudstone intervals, and wedge cross-bedding, tabular cross-bedding and small wave bedding is often found in sandstone intervals. The palaeocurrent direction of lower Cretaceous and Jurassic was east to south, with no great change in different well-blocks. The dip angle of the Mesozoic is large. Fractures are poor developed in Mesozoic, and most of fractures are in Jurassic, mainly developed in mudstone or argillaceous siltstone. Therefore, most of the fractures are invalid. The analyzing results on in-situ stress indicated that the maximum horizontal principal stress orientation in study area is near east-west. The study results can provide reliable basic data for further oil and gas exploration in this area.
The North Yellow Sea Basin is a new offshore oil and gas exploration area, with multiphase tectonic evolution, and the geological conditions are very complicated. Therefore, the HC exploration in this area is rather difficult. Based on acoustic-electric imaging logging data, analysis has been conducted on lithology, the types of bedding, fractures, palaeocurrent direction and in-situ formation stress orientation in the study area of the eastern depression of North Yellow Sea Basin, The study results indicated that the lithologies of Mesozoic in this area consists mainly sandy conglomerate, fine grained sandstones, siltstones and mudstones. Horizontal bedding is well developed in mudstone intervals, and wedge cross-bedding, tabular cross-bedding and small wave bedding is often found in sandstone intervals. The palaeocurrent direction of lower Cretaceous and Jurassic was east to south, with no great change in different well-blocks. The dip angle of the Mesozoic is large. Fractures are poor developed in Mesozoic, and most of fractures are in Jurassic, mainly developed in mudstone or argillaceous siltstone. Therefore, most of the fractures are invalid. The analyzing results on in-situ stress indicated that the maximum horizontal principal stress orientation in study area is near east-west. The study results can provide reliable basic data for further oil and gas exploration in this area.
2013, 33(4): 70-74.
DOI: 10.3969/j.issn.l008-2336.2013.04.070
Abstract：
Influenced by many factors, such as borehole condition and drilling fluids, the lithological profile obtained by the conventional logs will be in disagreement with the actual, resulting in poor accuracy in calculation results of reservoir porosity, and even failure in fluid property identification. ECS (Elemental Capture Spectroscopy) is a new well-logging technology developed by Sch-lumberger used for obtaining the formation elements, which can obtain accurate clay contents and clay types, obtaining better lithology profile. Besides, the ECS can be used to calculate the porosity accurately, improving the coincidence rate in logging data interpretation by combining with compensated density and compensated neutron log. In this paper, the principle and instrument parameters of ECS are introduced, and the advantage of ECS is described. Through application in SZ36-1 oil field, it has proved that ECS is very successful in logging data interpretation, and significant in application.
Influenced by many factors, such as borehole condition and drilling fluids, the lithological profile obtained by the conventional logs will be in disagreement with the actual, resulting in poor accuracy in calculation results of reservoir porosity, and even failure in fluid property identification. ECS (Elemental Capture Spectroscopy) is a new well-logging technology developed by Sch-lumberger used for obtaining the formation elements, which can obtain accurate clay contents and clay types, obtaining better lithology profile. Besides, the ECS can be used to calculate the porosity accurately, improving the coincidence rate in logging data interpretation by combining with compensated density and compensated neutron log. In this paper, the principle and instrument parameters of ECS are introduced, and the advantage of ECS is described. Through application in SZ36-1 oil field, it has proved that ECS is very successful in logging data interpretation, and significant in application.
2013, 33(4): 75-82.
DOI: 10.3969/j.issn.l008-2336.2013.04.075
Abstract：
Deep water area is becoming increasingly the focus of offshore oil & gas exploration and development. Because of the special sedimentary environment, the deep water drilling faces many challenges, such as unstable seabed, low formation fracture pressure, low temperature at seabed and so on. Jetting technology can solve the challenge faced in deep water top hole. Jetting technology can avoid fracturing the formation because of the high mud density and avoid impacting the cementing quality due to the low formation temperature. This paper presents how to design the depth and string structure through conductor force analysis, and how to optimize jetting parameters and technical measures taken to ensure conductor jetted in place. It provides a good reference for deep water drilling.
Deep water area is becoming increasingly the focus of offshore oil & gas exploration and development. Because of the special sedimentary environment, the deep water drilling faces many challenges, such as unstable seabed, low formation fracture pressure, low temperature at seabed and so on. Jetting technology can solve the challenge faced in deep water top hole. Jetting technology can avoid fracturing the formation because of the high mud density and avoid impacting the cementing quality due to the low formation temperature. This paper presents how to design the depth and string structure through conductor force analysis, and how to optimize jetting parameters and technical measures taken to ensure conductor jetted in place. It provides a good reference for deep water drilling.
2013, 33(4): 83-88.
DOI: 10.3969/j.issn.1008-2336.2013.04.083
Abstract：
TLP makes it feasible for application of dry wellhead to deepwater oil field development. Compared with conventional subsea wellhead, TLP can decrease the complexity and investment of deepwater oil field development, especially in the period of workover and operation in adjusting well. TLP has been used widely in GOM, North Sea and Indonesia. At present, there is not enough study on TLP completion design and operation procedure, which is restraint to the design of early oilfield development scenarios. Therefore, in this paper, the focus is on the influence of TLP to drilling and completion procedures. For different model rigs, TLP drilling and completion procedures are summarized. The requirements for casing tieback and heave compensation during TLP drilling and completion procedure are put forward, and the difference in temperature profile between dry wellhead and conventional water wet wellhead is analyzed in this paper, which can provide referenced for study of TLP drilling and completion technologies as well as design of early oilfield development scenarios.
TLP makes it feasible for application of dry wellhead to deepwater oil field development. Compared with conventional subsea wellhead, TLP can decrease the complexity and investment of deepwater oil field development, especially in the period of workover and operation in adjusting well. TLP has been used widely in GOM, North Sea and Indonesia. At present, there is not enough study on TLP completion design and operation procedure, which is restraint to the design of early oilfield development scenarios. Therefore, in this paper, the focus is on the influence of TLP to drilling and completion procedures. For different model rigs, TLP drilling and completion procedures are summarized. The requirements for casing tieback and heave compensation during TLP drilling and completion procedure are put forward, and the difference in temperature profile between dry wellhead and conventional water wet wellhead is analyzed in this paper, which can provide referenced for study of TLP drilling and completion technologies as well as design of early oilfield development scenarios.
2013, 33(4): 89-91.
DOI: 10.3969/j.issn.l008-2336.2013.04.089
Abstract：
In this paper, the advantage of setting casing shoe near the bottom of hole is introduced. This technique can improve cementing quality and avoid borehole wall collapsed during drilling. In addition, the technical requirements for setting casing shoe near the bottom of hole have been put forward in order to assure high quality wellbore, cleaned up of bottom hole, casing centralized, and the length of casing string is the same as borehole depth. Setting casing shoe near the bottom of hole has been applied successfully in Well Chengbeigu A, and the results indicated that BHA optimization, good mud property, wiper trip for running casing and making casing centralized are effective measurements for setting casing shoe near the bottom of hole.
In this paper, the advantage of setting casing shoe near the bottom of hole is introduced. This technique can improve cementing quality and avoid borehole wall collapsed during drilling. In addition, the technical requirements for setting casing shoe near the bottom of hole have been put forward in order to assure high quality wellbore, cleaned up of bottom hole, casing centralized, and the length of casing string is the same as borehole depth. Setting casing shoe near the bottom of hole has been applied successfully in Well Chengbeigu A, and the results indicated that BHA optimization, good mud property, wiper trip for running casing and making casing centralized are effective measurements for setting casing shoe near the bottom of hole.
2013, 33(4): 92-95,100.
DOI: 10.3969/j.issn.1008-2336.2013.04.092
Abstract：
Some fractured reservoirs might be penetrated during well drilling, resulting in lost circulation. If serious lost circulation occurs, complex conditions and accidents such as borehole collapse, pipe sticking and well blowout might occur, not only influencing the well drilling efficiency, but also causing great economic tosses. Therefore, it is essential to plug the fractured lost channel with pressurized lost circulation method. By using new method, namely adding the gangue (KZ) in the anti-high temperature sulphoantion drilling fluid, and raising in the activator processing fluid, the new drilling fluid system can be developed, which can improve the compressive strength of the formation. The experimental results have demonstrated that adding KZ can enhance the drilling fluid performance effectively, and improve the compressive strength of the formation, but also had proven feasibility of the activator can activates the KZ activeness. Regarding anti-high temperature sulphoantion drilling fluid, when the KZ is 30% and the activator is 30%, compressive strength of the formation achieves in a big way. This method can be very good to deal with the pressurized lost circulation of fractured reservoirs.
Some fractured reservoirs might be penetrated during well drilling, resulting in lost circulation. If serious lost circulation occurs, complex conditions and accidents such as borehole collapse, pipe sticking and well blowout might occur, not only influencing the well drilling efficiency, but also causing great economic tosses. Therefore, it is essential to plug the fractured lost channel with pressurized lost circulation method. By using new method, namely adding the gangue (KZ) in the anti-high temperature sulphoantion drilling fluid, and raising in the activator processing fluid, the new drilling fluid system can be developed, which can improve the compressive strength of the formation. The experimental results have demonstrated that adding KZ can enhance the drilling fluid performance effectively, and improve the compressive strength of the formation, but also had proven feasibility of the activator can activates the KZ activeness. Regarding anti-high temperature sulphoantion drilling fluid, when the KZ is 30% and the activator is 30%, compressive strength of the formation achieves in a big way. This method can be very good to deal with the pressurized lost circulation of fractured reservoirs.
2013, 33(4): 96-100.
DOI: 10.3969/j.issn.1008-2336.2013.04.096
Abstract：
On the basis of previous submarine pipeline survey results many times in the East China Sea, this article analyses and discusses the varied factors of cause current scour action, which can be divided into two major factors of the internal marine environment and the external environment change, and probably harm to the pipeline, and sums up the space condition of the pipeline, the sea floor form and the sea-bed erosion and deposition changes under the long-term current erosive, put forward some suggestions to inspection and maintenance of submarine pipeline.
On the basis of previous submarine pipeline survey results many times in the East China Sea, this article analyses and discusses the varied factors of cause current scour action, which can be divided into two major factors of the internal marine environment and the external environment change, and probably harm to the pipeline, and sums up the space condition of the pipeline, the sea floor form and the sea-bed erosion and deposition changes under the long-term current erosive, put forward some suggestions to inspection and maintenance of submarine pipeline.
Abstract：
The offshore petroleum supporting ship is very particular in operation tasks, with special shipping characteristics. Therefore, the experiences of ordinary shipping enterprise can not be used directly, a special way for energy saving and discharge reducing should be found. Through analyzing the various factors influencing oil consumption volume of offshore ship, the main factors controlling oil consumption volume have been determinated for offshore petroleum supporting ship, and the measures for energy saving and discharge reducing have been put forward.
The offshore petroleum supporting ship is very particular in operation tasks, with special shipping characteristics. Therefore, the experiences of ordinary shipping enterprise can not be used directly, a special way for energy saving and discharge reducing should be found. Through analyzing the various factors influencing oil consumption volume of offshore ship, the main factors controlling oil consumption volume have been determinated for offshore petroleum supporting ship, and the measures for energy saving and discharge reducing have been put forward.
