Abstract:The paper introduces the drilling operation of Wenchuan earthquake fault scientific drilling project, including drilling progress, technical problems encountered while drilling with the corresponding measures and the achievements obtained during drilling operation.

Abstract:This paper introduces the key drilling technology used in WFSD-2, including half-open core barrel coring technology, moving casing technology, down hole motor coring technique and drilling fluid technology. Several major accident management processes are summarized also.

Abstract:The WFSD-3 hole is one of the series of boreholes of Wenchuan earthquake fault scientific drilling project. During 2 years’ construction, many technical challenges, such as drilling in complex strata, large diameter undisturbed core sampling and borehole wall protecting under high geo-stress were overcome. This article especially focused on the construction technology and experience of the WFSD-3 hole and discussed some technical problems.

Abstract:This article introduces the drilling process of WFSD-3-P of Wenchuan earthquake fault scientific drilling (WFSD) project. A series of technical measures of high-density and low-filtration drilling fluid system, repeated reaming and mud recharging in pipe trip were taken to overcome drilling difficulties, such as borehole shrinkage in fault gouge formation, rock breaking and collapsed borehole enlarging. As the result, high quality undisturbed cores have been obtained and rich drilling experiences in earthquake fault have been accumulated.

Abstract:Deep hole core drilling equipment, including KZ3000 drill rig, high-pressure mud pump and wire-line coring rods and tools, is the first scientific drilling system in China, which was independently designed and manufactured to meet the needs of Wenchuan earthquake fault scientific drilling project (WFSD). The equipment is set fully hydraulic, high-speed top drive, large diameter and deep coring in one, featuring good comprehensive capability, wide process adaptability and high intelligence of manipulation. During the WFSD-2 deep hole core drilling, it worked well by meeting the design requirements in all functions. As stage innovations for deep drilling equipment, it has a potential market value in scientific drilling, deep prospecting and shallow oil and gas drilling.

Abstract:Wenchuan earthquake's Fracture Scientific Drilling (WFSD) was carrying out in the serious broken formation, one of the purposes is obtaining original cores to meet the geosciences requirements. Technologies of isolated fluid coring drilling, polycrystalline diamond compact (PDC) with sharp teeth and low drilling weight coring drilling, bottom hole power coring drilling and split barrel undamaged coring were applied in WFSD-2 and WFSD-3. The results indicated that the rate of drilling speed and roundtrip footage were improved in the serious broken formation. What's even more important was that the high-quality original cores had been obtained by these improved drilling technologies.

Abstract:This article introduces the liner cementation technology and its application in Wenchuan earthquake scientific drilling project. According to the conditions of complex formation in this drilling project, liner cementation technology which is suitable for broken formation and small annulus between borehole and casing string, has been developed. The key points of this technology include liner string design and installation and cementing slurry design and construction. This technology has been successfully used in 4 liner cementation operations.

Abstract:Due to the broken stratum, wall collapsing, landslide accidents and lost circulation happened frequently in the drilling of the second hole of Wenchuan earthquake fault scientific drilling project (WFSD-2). For preventing lost circulation during cementing, anti-leakage cementing technology with low density slurry was selected. Through multiple performance experiment of slurry, the formulation of low density slurry for anti-leak was optimized. This formulation was successfully adopted to cement the 168.3 casing in WFSD-2.

Abstract:〗The drilling formation of WFSD-3 hole is extremely complex with hard, brittle and broken formation and high water sensitivity formation appearing alternately, which brought huge hidden danger to the drilling construction. According to the special formation situation of the hole, based on the borehole stability theory analysis and the laboratory experiments, NH4-HPAN, K-PAM, SAS and KHm inhibitors had been selected out as the optimized additives for the mud system. In addition, the laboratory sand-bed non-filtration experiments and the ZNP-01 shale swelling experiments had been carried out to evaluate the blocking and inhibitory capacity of the mud formulations. This mud system has satisfactory application effects. The paper also summarized some treatment technologies in the application of mud maintenance, such as mud viscosity and gels control technique, the drill bit anti-balling technique and calcium invasion treatment technique while drilling cement plug, which have a good reference to drilling in the complex formation.

Abstract:The geological conditions were extremely complicated with poor wall stability in WFSD-2 hole drilling construction of Wenchuan earthquake fault scientific drilling project. Due to the water-sensitive formation of mineral water swelling, broken strata and stress release, the hole wall necking, collapsing and leakage happened many times. Through the adjustment and maintenance of the formulation, parameters, and solid control, LBM-GLA drilling fluid system with a low viscosity synergy powder and modified asphalt as the main raw materials was adopted in the construction; the above problems were successfully solved. This article mainly describes the use and maintenance of drilling fluid in each section of WFSD-2 hole.

Abstract:The formation conditions of Wenchuan earthquake fault scientific drilling project are very complicated. Broken rock formation, lost circulation and borehole shrinkage are encountered frequently. As a result, many drilling accidents, such as drill pipe sticking， drilling pipe breaking, objects dropping and so on happened and were successfully solved. Technical measures for preventing accidents, including scientific diagnosis and optimizing drilling method, drill tool structure and drilling mud system, have been taken to minimize accidents and ensure the smooth progress of scientific drilling project.

Abstract:Rotary steerable drilling technology is the most representative and advanced drilling technology in the world, and the core of the technology is rotary steerable drilling system. This paper summarizes the development situation of rotary steering drilling systems in China and abroad and analyzes the working principle of each system's steering mechanism. The paper also presents the development and perfection of the rotary steerable drilling system in the future.

Abstract:Based on the development experience of XY-4, XY-4A and XY-5 core drill, the advantages of automobile chassis technique, spring clamping hydraulic unlock roller-type chuck and weae-resistant frame were followed, and improvement was made on hydraulic system and creative designs were carried out in the elevator and rotary table support, the service performance of spindle core drill was greatly in improved.

Abstract:Drilling mud is very important in trenchless engineering construction. Discussion was made in this paper on the requirements to mud in trenchless engineering construction, containing mud materials, mud design, mud equipment and wasted mud treatment.

Abstract:A series of uniaxial compression experiment on the granite with the pre-existing flaw were carried out to study the influence of the inclining angle α of the pre-existing flaw on the progressive failure of brittle rock. The paper firstly summarized and discussed the axial stress-radial strain curves of progressive failure process, then analyzed the stress thresholds affected by pre-existing flaw and inclining angle α crack initiation stress σci, crack damage stress σcd, peak strength σf; stress-strain curves recorded by the strain gauges and the influence mechanism of surface flaw propagation of rock specimen. The experimental results show that in the loading test process of rock specimen with pre-existing flaw, the difference of inclining angle α is the main factor affecting the rupture pattern of brittle rock. So in the engineering applications of brittle rock with joint and fracture, the analysis on axial stress-radial strain curves can play the guiding role for the designs of underground excavation method and support form.

Abstract:According to the consolidation grouting construction for diversion wall in Dongsheng hydropower station, the paper summarizes the principles and precautions of drilling, crack flushing, water pressure test, pulping, grouting and sealing in the process of consolidation grouting. Coagulation and string slurry plugging were taken to deal with slurry leakage and string slurry in the process of grouting construction with good grouting effect.

Abstract:The paper introduced reinforcement measures for high fill slope control project. According to the negative effects of reinforcement measures, mechanical analysis was made; the causes of negative effects were discussed in geotechnical and engineering mechanics, the personal views on components safety and negative effects control were put forward.

Abstract:The quality of smooth blasting is directly related to the quality, safety and cost of tunnel construction. In the blasting excavation construction of Niujiaoshan tunnel, PDCA cycling quality administration method is adopted. According to the overbreak data collected from TM tunnel cross-section measurement system, in-situ inspection, discussion and analysis were carried out with the main influencing factors of smooth blasting being found out. Through formulating special improving measures and supervising implementation, the effect of smooth blasting is well improved. The average qualified rate and residual rate of blast hole reach to 95% and 85% respectively. The construction quality of tunnel is improved, the construction cost is decreased and construction progress is accelerated. In conclusion, favorable quality and economic effects are achieved.