Abstract:Qiandi well4 is a geological survey well of shale gas deployed in the southern section of syncline on Zhuohe dam in the depression fold belt of southeast Chongqing, whole depth coring was required. The well was designed with the depth of 2400m and completed with 2258m. Through the selection of drill rigs and drilling tools (drill bits) and the optimization design of wellbore structure, the maximum lifespan of the drill bit is up to 466m and the drilling efficiency is increased by more than 10%. The average penetration rate of the whole well is 1.78m/h and drilling-month efficiency is 535m, of which the second section drilling-month is 704m, rapid and safe drilling is realized.

Abstract:In the horizontal well drilling construction in Mo116 well area, which is located in the south of Mobei oilfield, there are the challenges of undergauge, drilling tool jamming, borehole collapse, mud loss, blowout and hard rocks. The optimization of horizontal well design and technical study on drilling trajectory control are carried out in this area to avoid complex downhole accidents, shorten drilling cycle and reduce operating risk. According to the analysis on drilling data of this area, the optimization schemes of wellbore structure and well trajectory control are put forward; based on the analysis on previous drilling data and drill string mechanics, the horizontal drilling BHA and drilling parameters are optimized; through the drilling fluid system optimization, the poor borehole wall stability, high friction and sticking probability in directional drilling sections are improved. By the application results, optimal and fast drilling in horizontal wells is realized, the average ROP of the second directional interval and the third interval are increased by 27% and 30% respectively than those before optimization, and one trip is realized in M614 and other wells for horizontal sections drilling.

Abstract:By the practice of Qiansuidi well1 drilling engineering, from the well structure, coring process, wall plugging technology, wellbore quality control and other aspects, the construction technologies of shale gas basic geologic survey well in south karst area are analyzed and summarized, and based on the geological record of borehole core of Qiansuidi well1, gas logging while drilling, organic geochemistry and water immersion test, the analysis and summarization are carried out on the stratum structure and gas bearing characteristics of shale gas in Suiyang area of north Guizhou to provide the geological basis for the exploration and development of shale gas in this area.

Abstract:Youshashan oilfield is located at Qaidam basin, the complex geological structure, formation cracks development, low pressure coefficients, frequent leakage and long drilling cycle have seriously restricted the exploration and development benefits in conventional mud drilling. In view of these difficulties, aerated drilling tests are carried out in 4 wells, the results show that the aerated drilling can effectively solve the drilling problems in the leakage formation of Youshashan oilfield and improve the POP; compared with conventional mud drilling technology, the average plugging time is reduced by 6.32 days, the leakage loss is reduced by 54.5% and the ROP is increased by 1.1 times. The success of the tests are of guiding significance for the research and application in optimized and fast drilling technology in this block.

Abstract:Hot dry rock can be obtained by drilling, which is a kind of clean and reproducible geothermal resources. By analyzing the difficult challenges faced by current conventional hot dry rock drilling technology such as slow rate of penetration, unstable performances of downhole tools and drilling fluid and freqent complicated downhole accidents, the discussion is carried out on the application prospects of liquid nitrogen in hot dry rock drilling. It is concluded that liquid nitrogen has advantages of high efficiency in rock breaking, effective improvement of the hot energy extraction, solving high temperature tolerance and well leakage for hot dry rock drilling. The paper puts forward some key technologies of low temperature performance of drilling tools with liquid nitrogen, regulation and effects of carrying cuttings by liquid nitrogen, wellbore pressure control, drilling parameters optimization and well wall stability in hot dry rock drilling.

Abstract:Affected by tectonic, there are problems of complex geological conditions, large inclination, multiple pressure systems coexisting and high mudstone content in Horgos anticline, frequent complicated accidents seriously restricted the oil and gas exploitation and development process in this area. Based on the analysis on logging data, ground breaking experimental data and complicated well drilling and completion situation, the setting position was determined for 4interval casing program of deep exploration well in Horgos anticline, and aiming at high complicated accident rate in Anjihaihe formation, by using high density oil-based drilling fluid, mudstone hydration was inhibited to realize safe drilling. The optimized casing program was applied in deep exploration well H11 in Horgos anticline, drilling was carried out under the pressure of Anjihaihe and Ziniquanzi formations for the first time, it took 5.5 days to penetrate Anjihaihe formation without well leakage. This successful application not only provides the basis for the design of the casing program of the deep exploratory well in the area, but also provides guidance for subsequent conventional casing program with 4 sections changed to be 3 sections.

Abstract:The East China Sea oil and gas field is currently one of the main offshore exploration and development areas in China, where the main reservoirs are deeply buried, the compressive strength of deep strata is above 100MPa with the conditions of poor drillability and high formation temperature. There are problems of wellbore instability, low ROP, difficult trajectory control and some others in drilling process. In view of the above, through the investigation of the related efficiency raising technologies both in China and abroad, the research and practice of effective drilling in the deep formation of East China Sea are carried out and hydraulic impact tool is selected, which has the advantages of simple structure and high reliability. By the analysis on the installing location and the optimization of operation parameter, the existing drilling equipment and technological parameters are kept original, while the innovative coordination of rotary steering and hydraulic impact tool is put forward, in the application of wellX4H, the ROP is significantly improved by 30%～200%.

Abstract:Coalbed methane surface drainage wells has undergone through the stages of conventional vertical wells, directional wells, Ushaped wells and pinnate branch wells, the Ushaped well has gradually become the new favorite method of CBM surface drainage with the advantages of synchronous production, less land occupation and maximizing coal seam fractures connection. Taking YQ01 well group as an example, this paper sorts out the problems in the construction of Ushaped butted wells and puts forward the attentions and technical measures in main construction stages to solve the difficulties in well trajectory control, high occurrence of complicated situation and high accuracy of horizontal and vertical wells connection with drilling cost saving, which provides technical reference for the subsequent construction of Ushaped butted wells of CBM.

Abstract:In the previous reduction transmission device of polar deep ice drilling, planetary gear reduction transmission device is prone to appear fatigue failure, which results in short service life of reduction transmission device. In view of this problem, the improvement design is made on the reduction transmission device of armored cable electro-mechanical drilling tool, the device structure and size are determined; the meshing force of the device is analyzed and the strength estimation is carried out. A 3dimensional solid model of the reduction transmission device is built by using Inventor software and ANSYS Workbench software is used for the static analysis on the device structure. The results indicate that this oscillating tooth reduction transmission device can meet the design requirements and provide a basis for the optimization of reduction transmission device design for polar deep ice drilling.

Abstract:In view of the problems of existing mechanical bottom expanding drilling tool in rotary drilling construction, such as separation of hole expanding from soil taking and cleaning, complicated processes, difficult sediment cleaning and low construction efficiency, a new type of soil collecting bottom expanding drilling tool is developed. This paper focuses on the design theory of underreamed pile, the structure design of the soil collecting bottom expanding drilling tool, the finite element numerical analysis and optimization improvement of the key components and the prototype trial manufacture as well as field tests. The test results show that this new type of soil collecting bottom expanding drilling tool integrates functions of reaming and soil collecting to reduce the technological processes and improve working efficiency, which meets the construction requirements of rotary drilling for underreamed pile.

Abstract:The bearings of downhole power drilling tool, being one of the key components of drilling tools, bear the impact, friction, corrosion and other harsh working conditions, the reliability and longevity are essential to ensure the smooth drilling. In this paper, the frequently-used thrust bearing and the stabilizing bearing of the downhole drilling tools are studied in detail; the deep analysis on the development status, main characteristics and development trend of metal rolling bearing, sliding thrust bearing and stabilizing bearing are carried out respectively and the development and improvement direction of bearings for downhole power are pointed out, which can be used as reference.

Abstract:Air DTH hammer reverse circulation drilling technology is often taken as the first scheme in large diameter boreholes and rescue holes construction because of its advantages of rapid drilling and strong cuttings carrying capacity without borehole wall being washed out. However because reverse circulation DTH technology is not enough mature with high manufacturing cost and short service life, the research on reverse circulation drilling technique with normal circulation DTH hammer is carried out and the process matching drilling tools are developed, including the improvement of the large diameter double-wall drill rod and the development of double-wall stabilizer, wind resistance ring and positive & negative joints. The practice of collapse accident treatment in Pingyi gypsum mine shows that the developed drilling tools can reach the expected goal and provide hardware support for the promotion of air reverse circulation drilling technology.

Abstract:In order to improve the service life and efficiency in deep hard rock drilling for “SKⅡ” well, high performance matrix formula and high strength welding material are selected with reasonable bit structure and waterway structure design. Good results of the developed φ216/124mm diamond coring bit have been achieved in “SKⅡ” well drilling. The design and the application of the diamond bits suitable for deep hard rock drilling are introduced in this paper.

Abstract:Sand conglomerate formation is a difficult drilling stratum in drilling engineering, how to improve the drilling efficiency and bit service life in sand conglomerate stratum have been the important problem in engineering practice. In view of the problems of early breaking of common cone bit outer teeth and low comprehensive use index in the drilling process of Zhenzhuchong quartz sand conglomerate strata in Yuanba area, the stratigraphic lithology, drill bit usage and failure are analyzed, and especially aiming at the bit cutting structure, tooth material optimization and bit gauge retaining strengthening, new HJT547GKL tri-cone drill bit is optimally designed and developed. Field test result shows that this new type of cone bit has high stroke footage in Zhenzhuchong formation of Yuanba area, which is reliable, practical and suitable for hard formations and formations with hard interlayer drilling with simple structure and good gauge retaining.

Abstract:In order to solve the construction difficulties of the rotary drilling rig in the hard rock strata, by drawing on the mature process method in the field of geological drilling, the method and equipment for the reverse drilling process of the pneumatic DTH hammer for the rotary drilling rig are developed. Without changing the structure of the rotary drill rig, the reverse drilling tools of the pneumatic DTH hammer are applied to achieve fast hard rock drilling to solve the difficult cuttings expelling in large diameter drilling, and the environmental requirements are met. According to the construction requirement of large diameter pile foundation and the application characteristics of the DTH hammer, the reversed circulation pneumatic DTH hammer drilling tool is designed, the double channels for air and water with large center diameter can meet air inletting and cuttings expelling. Reversed circulation double drill pipes are concentric type with reliable sealing. The hexagon structure is used for the drilling tools connection. The feasibility of the technology and equipment are verified in the construction of Xiamen subway.

Abstract:Through the summary of existing slope support methods and the analysis on additional stress influence factors of pre-stress produced by anchor cable, and combined with the geological structure characteristics of the rock mass slope and the research on additional stress distribution, under the condition of ensuring the slope ecological harmony and not changing the natural environment, slope lateral confinement method is put forward, by which, landslide is effectively prevented and controlled in the application.

Abstract:According to the problems of stratum broken, uneven rock hardness, serious drilling mud leakage, low drilling efficiency and difficult coring in Sanhe coal mine goaf subsidence area of Hebei, a series of drilling technical methods were adopted to improve drilling efficiency on the premise of ensuring the quality of core drilling engineering. The accurate and detailed geological data are provided for preliminarily ascertaining the scope of ground subsidence of Sanhe coal mining area, the development characteristics and harm degree, which can be the basis for the development and utilization of coal mine goaf subsidence area and the next exploration and urban & rural planning.

Abstract:According to the transfixion construction of 2nd chute in open pit mining field of Zijinshan gold-copper deposit, the paper elaborates in detail the transfixion blasting construction of chute VRC method. Considering the influence of blasting time limit, a feasible solution was proposed. By the smooth chute transfixion experience and the analysis on the construction, the attentions for VRC method in chute transfixion blasting operation are summarized.

Abstract:Based on the background of the landslide of Panzhihua, considering the influence of soil tensile strength, combined with the shear strength and using “equal reduction method of tensile shear strength”, the landslide stability is studied in this paper. Through the indoor experiment, the influence laws of moisture content on the different rock and soil layers of the landslide are analyzed; it is found that the internal friction angle and cohesion of the sliding belt soil are more obvious. By using the finite difference software FLAC and equal reduction method of tensile shear strength, the landslide tensile shear critical reduction coefficient, critical internal friction angle and the critical cohesion of the landslide are obtained; it is also found that the landslide there is most sensitive to the internal friction angle of the soil, but the influence force of the tensile strength and the cohesion are very close, so that it can not be neglected. The slope shoulder displacement is greater than the slope base displacement and the slope shoulder displacement changes should be noticed.

Abstract:Taking an exploration horizontal hole construction as the example, which was in the oversize dangerous rocks zone in Huangyanwo and Banbiyan of Yangtze River Wuxia, the construction scheme of drilling platform was explored, the construction was carried out under the conditions of approximate vertical rock beetling wall without ground foundation. With the stress system of diagonal braces and anchorage structures, a complete set of construction technology is developed by the mechanical analysis and calculation, which has certain guidance and reference value for solving difficulties of similar engineering construction platform.