Abstract:According to the borehole instability of coal bed and carbonaceous mud strata and support pressure of directional drilling in the course of horizontal drilling in Jingnan region of Erdos, the study was carried out on anti-caving and formation blocking as well as lubricating and resistance-reducing technologies of drilling fluid. A drilling fluid formula with good anti-caving and lubrication ability was developed, which brought shale rolling recovery ≥98% and extreme pressure lubrication coefficient up to 0.05. In the application tests of 2 wells in the field, the average well diameter expansion rate in application well sections were 1.71% and 4.06%, respectively and the drilling tool friction resistance was 40～80kN. Drilling and well completion was conducted successfully.

Abstract:Core recovery has always been focused on in geological core drilling, which is also an important evaluation index for core drilling. It is difficult to have good core quality by traditional core drilling method in loose, soft and salt formations, especially in those formations containing soluble salt. By the use of wire-line coring drilling, ideal coring effect can be achieved in complete formation; at the same time, the labor productivity can be greatly improved with labor intensity reduction. For the loose and soft layers, coring drilling is sometimes more difficult than traditional drilling. Taking the case of scientific drilling project in Dabuxungan salt playa, exploration and research were made on how to improve core recovery in the drilled surface layer and loose layer. The practice proved that wire-line core recovery can be largely improved in loose, soft, unconsolidated and salt bearing formations by the improvement of flushing fluid performance, property of core lifter and bit water way. The average core recovery is raised from original 30% up to 96%.

Abstract:In Tuoputai Area, the upper formations are mainly composed of sand-shale layer and conglomerate sandstone, long segment and high permeability loss easily occurs with unclear loss layer. Based on the evaluation on plugging material compatibility and reasonable gradation, a plugging agent used in drilling was optimized, it is suitable for high permeability loss zone with less influence on the rheological property of drilling fluid, can reduce the amount of API drilling fluid filtration and has bearing capacity of more than 10MPa after sand bed sealing. It is showed in well TP328X that high strength elastic graphite particle composite gel has effective sealing effects in high pressure difference and high permeability leakage conditions and is especially suitable for complex well conditions such as unclear leakage layer, well kicking accompanied with circulation loss and open hole.

Abstract:Cleanout service plays an important role in hydrological well completion. With an example of packed backpressure cleanout, well cleanout by water hammer effect is elaborated in this paper. It is showed that by the model simplification, the water head difference caused by water hammer effect can reach 136m; the good effect of well washing is proved in theory. Based on the analysis on variance in the water hammer pressure formula, 3 methods for well cleanout optimization by water hammer effect are put forward: put suction nozzle of pump at the bottom end of packed interval, increase the pump volume or shorten the length of packed interval.

Abstract:The Quaternary overburden layer is thick in Wanglou iron ore area of Henan Wuyang with complex formations and breaking rocks, collapsing and diameter shrinkage easily happen, the survey drilling is difficult. According to this situation, appropriate construction process and technical measures were adopted, such as equipment selection, borehole structure, casing, bit selection and flushing fluid technology. This paper summarizes these experience.

Abstract:Because of the variety of stratigraphic types, broken rock mass formation and complex geological structure in Shaling goldfields of Laizhou, drill pipe breaking often occurs in small diamond drilling construction. Based on the investigation and analysis, a “shell” shaped fisher was developed, which is used for drill pipe or casing breaking accidents, the efficiency and effect of accident treatment are highly improved. The working principle and attentions in use are outlined in this paper and the existing problems and limitations are also pointed out.

Abstract:In order to reduce the harm of coal mine gas and realize comprehensive utilization, the large diameter gas hole project is encouraged and supported in China. This paper shows a large diameter gas hole with diameter of 850mm and termination depth of 401.6m and in detail introduces the special construction technologies after small diameter hole drilling through the tunnel and related technical measures in drilling methods, drilling tool grading, drilling technical parameters, flushing fluid, borehole rolling and straightening, protection casing installation and consolidation at hole bottom, circulating mud filling, pipe lowering and fixing and hole construction for drainage.

Abstract:Mudstone developed in Shihezi group of Daniudi gas field and the inhibitive properties of the drilling fluids are poor, construction safety and progress are seriously affected by borehole instability. Based on the analysis on the instability mechanism, a study on the inhibition of potassium amino polymer drilling fluid was made. Mineral contents of montmorillonite and illite mixed layers were increased to evaluate and optimize higher inhibitive potassium amino based polymer drilling fluid system, which has lower liner expansion ratio and higher roll recovery and is of great practical significance to prevent borehole instability of mudstone section in Daniudi gas field.

Abstract:Flushing fluid’s density is very important in the drilling project. Large density is helpful for wall protection and dreg suspension but will increase drilling resistance at the same time; while too small density will reduce the capability of dreg suspension and influence the stability of wellbore. Based on the mechanical analysis on the borehole stability, simulation device was established to simulate the stability of borehole wall. Meanwhile, the stability of wellbore was also simulated by finite element method to obtain the reasonable safe density window of flushing fluid. Comparison results show certain feasibility of simulation using ANSYS finite element analysis software to determine the safe flushing fluid density window. Using finite element simulation analysis not only can reduce the cost of flushing fluid test in earlier stage, but also can provide the safe density window of flushing fluid, which has practical reference value to optimize the density of flushing fluid.

Abstract:In order to prevent working environment pollution, a blowout preventer is necessary to carry high-speed upward downhole dust or slurry away from the hole top during DTH hammer drilling. Comprehensively considering the main factors of the structure characteristics of hole top workbench for truck driller, the shape features of matched drill pipe with taper at the joint, the drilling process characteristics and the mount-dismount operating conditions, a low pressure blowout preventer for air DTH hammer drilling used on top drive truck driller was designed with the advantages of simple structure and convenient installation. The borehole entrance sealing was conducted by interference fit between rubber sealing plug and drilling pipes, the sufficient compensation quantity of rubber sealing plug is effective for sealing of those pipes with large outside diameter difference; the rubber sealing plug can be easily replaced while adding drilling pipes; 2 diversion ports were set up to reduce returned fluid pressure drop. It is showed by the field application that the blowout preventer can effectively prevent the dust or slurry leakage and obviously improve the construction environment.

Abstract:XDQ-1200 drilling rig was designed specifically for mountain foothills, the quality requirements was very strict. The finite element static analysis was made on the structural parts of power head to optimize the strength and stiffness of box. In the case of satisfying the stress, try to reduce the box quality in order to achieve weight reduction. The design background, concept and optimization process of power head for XDQ 1200 drilling rig are introduced.

Abstract:Accumulative hydro-hammer is of reacting type with low energy consumption, small displacement, large impact power and high energy efficiency. Take the example of internal valve structure, the paper introduces the hydraulic accumulative hydro-hammer about its structure features and working principles, and elaborates the developing process, technical advantages and application effects. The existing problems and the improvement suggestions are also put forward.

Abstract:Wire-line winch is important in wire-line core drilling. Aiming at the existing problems in winch application, automatic rope-arranging device and counter were designed; the ideal design effects have been achieved in the field tests.

Abstract:In the drilling process of horizontal well with three-dimensional trajectory of unconventional reservoirs, the drilling speed is seriously restricted by the backing pressure effect. Hydraulic oscillator can generate axial vibration to reduce the friction between string and hole and significantly reduce the backing pressure influence so as to achieve the fast drilling. This paper introduces the working principles and performance of AG-Itator hydraulic oscillator as well as the test application effects in a variety of areas of China. It is showed that by the application of AG-Itator hydraulic oscillator, ROP can be significantly increased with shortened drilling cycle, which is an effective method to increase drilling speed for horizontal well with three-dimensional trajectory of unconventional reservoirs and is worth popularization and application.

Abstract:The paper introduces the development situation of aluminum alloy drill pipe both in China and abroad and analyzes the advantages of aluminum alloy wire-line coring drill pipe in geological drilling. φ71mm×5.5mm aluminum alloy coring drill pipe body and steel connection structure were designed in detail, the main technical parameters were obtained by the static tension and torque tests on the rods.

Abstract:To increase the fishing success rate and ensure the safety of upper drilling string in the treatment of drilling pipe breaking and sticking accidents, a safety joint with jar was developed; good results were achieved in field application. This paper introduces this safety joint about its design idea, structure principle, operation technology and field application effect.

Abstract:In the prospecting drilling construction project in complex formation of Yangzhai coal mine in Qianlong of Guizhou, the construction organization and management were carried out in the aspects of job responsibilities clarifying, detailed management procedures, strict examination of admittance conditions of construction team, selection of drilling methods and wall protection measures, proper use of flushing fluid and proper drilling operation, serious professional technical training, technical explanation before construction and technical instruction in the construction process. In this case, technical difficulties of collapsing while drilling in high gas and water gushing coal strata were overcome, the very difficult drilling project was completed successfully.

Abstract:This paper introduces an engineering of foundation pit support in Zhengzhou. Because of the complex surrounding environment and soft soil in the depth range of foundation pit, the combined application of slope protection pile, pre-stressed anchor cable, perforated pipe pile and passive soil consolidation around pile were used to ensure the safety and stability of 17~20m deep foundation pit wall and the existing buildings. Especially with once-forming anchor construction technology by high pressure, the hole-forming difficulties in silt and soft soil below water table were solved and the anchor cable quality was improved.

Abstract:Guanzhou hydropower station is located in remote Danba County, because there is no qualified clay, which has to be replaced by bentonite with high project cost. As it is very difficult for mud purification and recycling in cut-off wall construction by use of percussion drill, the study is specially made and good effects are achieved with mud cost saving.

Abstract:A building with complicated surrounding environment was planned to be demolition blasted, except for the toppling direction, around it are close-range existing facilities or experimental reserved buildings in three directions. A series of blasting and safety technical measures of unidirectional dumping with∠ shaped blasting cut, rational blasting parameters, reliable blasting network, rigorous protective structure, appropriate reinforced steel cutting technology at supporting column were taken in the design with meticulous construction management to ensure precise designed collapse direction in a safe range without recoil. At the same time, the harmful effects of blasting vibration, blasting slungshot and air shock wave were strictly controlled.