Abstract:This paper focuses on field experience in block 1 of Yemen Republic. The wells have to be drilled through hard limestone and severe fractured thief zone. Low rate of penetration (ROP) and total mud loss were encountered during drilling operations. On the basis of geological characteristics, drilling fluids and economy, the adaptability of gasified fluids drilling in block 1 was evaluated. At the beginning of field application, gasified fluids drilling was only used in the surface interval because some downhole problems, such as lost circulation in sand formation with aerated fluids and the casing stuck. According to these problems, the well structure, air and fluids injection parameters, formulas of foam and aerated base fluids were optimized, and aerated blind drilling was chosen as the principal means to penetrate the severe lost circulation formation, the perfect technical measures were also formulated. The experience of 3 field wells showed that with only air, only foam or only aerated fluid could deal with a part of drilling problems; the integrated application of gas drilling could satisfy the requirements of ROP improvement, borehole wall stability and leakage prevention.

Abstract:Mathematic essence of the highest level azimuth rectifying means to get tool face angle under constrained conditions for the largest azimuth variation. The constrained conditions have not been considered in several solution methods in the existed literatures, this makes the related calculation formula lack strict mathematic foundation. A standard solving method with constrained minimization problems, Lagrange multiplier method, was used for the new mathematical expression of highest level azimuth rectifying and the calculation formula with optimal solution was derived.

Abstract:According to the collapsing formation which is difficult to control the severe leakage and can not be effectively cemented, a new settable working fluid was developed. It is based on the conventional drilling fluid with good suspension capacity, rheological property, salt-resistant ability and good compatibility of drilling fluid, its suitable solidification intensity can be reached under certain conditions and can be used as sealing fluid or as cementing fluid in borehole instability formations to improve the sealing and cementing effect.

Abstract:Discussion is made on drilling construction of borehole wall protection & leakage control, borehole structure, accident prevention and treatment method in the deep prospecting project in Xiaoqinling, especially the application breakthrough of washing fluid with strong wall protection performance and multilevel casing technology basically resolved construction difficulties in thick overburden with buried depth of 600～800m in quaternary and tertiary with fault gouge.

Abstract:The southeast uplift formation of Songliao basin is mostly Mesozoic cretaceous with good drillability and high ROP in the upper formation of Denglouku but the drillability becomes poorer below the middle part with dense sandstone and hard mudstone. Serious and frequent drill jump were encountered in drilling construction, which is very harmful to the bits, drilling tools and equipments. By the test application of shock absorber, the influence of drill jump was reduced with 21% average ROP increase and the drilling cycle was reduced by an average 127 days. Integrated drilling costs have been reduced in a certain level and the potential harms and impacts to equipments and drilling tools were greatly reduced.

Abstract:Analysis was made on the mechanism of silicate polymer washing fluid system, a set of washing fluids especially for long borehole section with hidden downhole accidents in core drilling of sandstone uranium deposit. The practice shows that this washing fluid system can satisfy all requirements of wire-line coring drilling technologies and has good effects in dealing with complex sandstone formations.

Abstract:Tangshan Caofeidao hotel is located in the Quaternary strata area along the coastal region. According to the drilling technical difficulties of deep geothermal well in Quaternary hole shrinkage soft layer, low fluid loss and high density sodium soil slurry and pump capacity control were adopted for wall protection drilling in the design and construction. The paper summed up the drilling and completion technologies of a deep geothermal well in hole shrinkage soft layer.

Abstract:To effectively develop the oil storage and residual oil in old well area of Zhanazhol oil field, casing window sidetracking was successfully used in well 2358 for old well reconstruction with single well production recovery and promotion.

Abstract:The reasons of the breaking of wire-line coring drilling pipe are analyzed and the ultrasonic inspection test for wire-line coring drilling pipe is studied. Moreover, the specific detection methods, equipment and process are analyzed. There is practical significance to effectively predict the fracture of wire-line coring drilling pipe and reduce the accidents rate with economic loss reducing.

Abstract:Based on the production and the application practice, the failure modes of external threaded drill rod and tool joint were analyzed with the processing means and methods of prevention.

Abstract:Take the example of reconstruction project of Yitong River drainage pipelines in Changchun, based on the change of jacking force measured in jacking process by using slurry balance pipe jacking in medium coarse sand formation, the factors affecting jacking force and the changing rule were systematically studied, and the calculation of jacking force were analyzed and compared to the field measured data, finally the measured data were numerically analyzed with Matlab software, calculation formulas of jacking force and friction under the condition of medium coarse sand formation were deduced.

Abstract:With the construction case of super deep foundation reinforcement of a metro project with MJS engineering method, the paper discussed the main points of technical management in construction process with some experience and understanding.

Abstract:In view of partial seepage in underground continuous wall during structure excavation in Hangzhou Tiancheng square, cement-sodium silicate double liquid grouting technology is used to ensure the safety during excavation. It can provide reference in the similar deep foundation pit construction.

Abstract:The paper discussed some problems of CFG pile applied in foundation treatment in super-thick silt layer with the attentions, introduced the common accident and prevention measures and especially put forward the prevention measures for hollow pile to ensure slope stability of foundation pit.

Abstract:In the process of the foundation pit excavation of a freezing room with 810 meters depth, which is in a large foundation pit in coastal soft soil area, collapse caused by anchor bolt failure occurred. By the analysis and calculation comparisons of simulation working conditions element internal force in 5 aspects: insufficient consideration of digging depth, bad geological environment, bolt spacing exceeding the design requirements, insufficient range of step-slope by soil dumping and taking higher value of anchor pullout capacity, it was concluded that the increased anchor tension design value greatly exceeded the anchor anti-pulling force capacity by the comprehensive influence of above 5 aspects, which led the anchor bolt failure and the instability of foundation pit.

Abstract:The construction of post-grouting technology for bored pile in Zhengzhou is presented with the static loading test results of a single pile; and by the economic benefit analysis on the post-grouting for bored pile construction, it is elucidated that post-grouting technology is an effective measure to improve bearing capacity of single bored pile with good technical and economic benefits.

Abstract:Discussion is made on some related problems in cutoff wall construction with engineering cases and some opinions and improvement suggestions are put forward.

Abstract:To optimize grouting design scheme of the left spillway for a power station, comprehensive survey was made for borehole arrangement and single borehole grouting tests were demanded. In order to ensure construction quality, the process flow was optimized, the equipment and personnel were strictly selected and single borehole grouting tests were made at representative regions according to the grouting specifications and design requirements, such as gate hoist, 2 sides of spillway and overflow weir with good grouting effects, which could be the basis for sound grouting design scheme.

Abstract:According to the deformation in a deep foundation pit excavation process, analysis was made on the basic cause of engineering foundation pit deformation; the reasonable optimizations were timely implemented on the original design scheme with effective limits to the deformation of foundation pit with the safety ensuring on surrounding buildings of the foundation pit, cost saving, convenient construction and short construction period.

Abstract:The development process of a new rapid anchoring technology applied in vertical high fill slope control project is introduced, that is horizontal direction rapid anchoring cable by pre-stressed concrete tube. The mechanical principles, the structure and the features were described, and the construction process and the technical points of the new rapid anchoring cable were introduced with engineering case.

Abstract:Bionic impregnated diamond bit has the characteristics of high efficiency and wear resistance, which meets the requirements of the exploration of natural gas hydrate and the conditions of the construction site in Mohe. This paper introduces the design and manufacturing of bionic impregnated diamond bit suitable to the characteristics of Mohe formation. The paper analyzes the drilling conditions of nonideal bit and puts forward the comprehensive analysis for evaluation of bit performance to objectively and truly reflect the actual bit drilling capacity. The drilling results of MK-2 scientific drilling test well of Mohe natural gas hydrate indicate that the service life and the drilling speed of bionic impregnated diamond bits are 73% longer and 22% higher than ordinary diamond impregnated diamond bits.

Abstract:Based on the comparative analysis on different cutting mode and according to the engineering case, test analysis was made on the blasting effects of different cutting mode. It is held that both inclined underholing and parallel cut have defects, the suggestion was put forward for adopting and wildly using quasi-parallel cut.