Abstract:Geological structure is complex with soft seams and poor permeability in Zhaozhuang coal mine of Shanxi. Wall collapse of gas drainage hole caused by unstability leads to gas drainage channel blocking, low extraction rate and poor drainage effect. By the technology that drill pipe is kept at the completion of drilling construction and in which gas extraction screen liner is lowered to protect the wall, gas drainage channel can be formed after drill pipe is lifted. The application results show that the pipe lowering efficiency is largely improved comparing with that of traditional drill casing technology. The pipe length is up to more than 98% of the hole depth, which is helpful to improve the efficiency of gas drainage and has great significance for coal mine safety.

Abstract:Geothermal energy is a new kind of green energy and its development has formed a certain scale in some regions in China. The geothermal tail water recharge as a sustainable recycling technology currently becomes a prominent problem; especially when it is applied in sandstone layer. There is abundant geothermal energy in Fen-Wei basin where the scale development has formed. The sandstone recharge was tried in WH1 geothermal well in Xianyang for the first time with the related data of construction and recharge. Tail water recharge test was made to accumulate the construction experience, which lays the foundation for subsequent construction.

Abstract:Air DTH hammer drilling is a preferred technology in bed rock area， which by tradition is suitable for hard rock drilling(in hard, brittle and broken formations); while for loose formations, conventional mud rotary drilling or percussive drilling should be used. Based on the test on typical unconsolidated formation drilling, it is proved that normal drilling can also be realized in loose overburden layer by air DTH hammer with advantages of high efficiency, low cost and small labor intensity, the highest drilling efficiency is up to 87m/h and 72m/h in clay and moist clay drilling respectively. This result provides an effective method to hole opening or the first spud section drilling for the exploration of shale gas, geothermal energy, coal seam gas and underground water in overlaying layers and solves the water shortage for drilling fluid in water scarce areas or serious leakage formations and avoids the difficulties in the complicated processes of conventional mud rotary drilling.

Abstract:The motion characteristics and control in hole make a big difference in improving the efficiency of drilling and reducing the hole accident in the process of lifting tool during polar ice core drilling. Depending on the summarization of the characteristics of polar ice drilling, analysis is made on the impact to the borehole structure, drilling tool structure, the quality of the drilling tool and rheological behavior of drilling fluid. The characteristics of two stages of tool motion in drilling process, the existence of stagnant layer and the influence factors determine the quantity and range of the fluid disturbance. A lifting test-bed and test method are developed for armored cable hanging tool testing, by the real testing of the falling process of drilling tools with three different diameters and three different weights, the conclusion is drawn that the drilling down speed presents quadratic relationship with the diameter of drilling tool and linear relationship with the quality of drilling tool. The result has a vital theoretical and practical significance in improving the drilling efficiency in Antarctic, saving the service auxiliary working time and guiding the acture work.

Abstract:Most of the damage of oil well casing is caused by non-uniform load, the non-uniform of external load and some other factors greatly reduce the bearing capacity of the case. There is important practical significance to reveal the influence of these factors on the collapse resistance of casing. According to the characteristics of hoop stress on casing under non-uniform elliptic load condition, a calculation model of hoop stress for ideal casing is established by the theory of material mechanics. Analysis is made on the regularity of stress distribution, the results show that the dangerous point is on the inner wall of casing by 90 angle between circumferential direction and the maximum horizontal stress, which has good consistency with the finite element numerical simulation result. Based on the stress state at the dangerous point, the new formula is proposed to calculate the equivalent external pressure on casing in different non-uniform loading. The calculation shows that non-uniform of elliptic load has great influence on casing equivalent external pressure; the more the non-uniform and the larger diameter-thickness ratio are, the poorer the bearing capacity of external load is and more easily collapse failure of casing happen.

Abstract:As the applications of drilling mining technology are extended from petroleum and salt well to trona solution and CBM mining industries, the thin or weak ledges can provide only a smaller target area, which makes the target-hitting more and more difficult. Different kinds of ranging technology depend on different size of target cavities so as to realize the connection between the drilling well and target well. In this paper, the analysis is focused on the deviation errors produced by MWD and rotary magnet ranging system, and the appropriate size of the cavity development is proposed.

Abstract:Due to the core drilling depth increasing with more auxiliary work time, improvement of round trip efficiency is imperative. Without large scale of drilling equipments renewal, according to the difficulties in salt rock coring in Ningjin-Xinji exploration area, the supporting research was made on optimization of well program, rapid drilling in non coring section, salt water drilling fluid system and safe coring in salt rock layer, which was successfully applied in the field practice.

Abstract:There are a series of drilling technical challenges in Y oilfield horizontal wells of Iran, complex geological lithology, uncertain geological target area, long uncased hole section, big borehole friction and difficult trajectory control of long horizontal well section. Based on the practice in the first phase horizontal well drilling in this oilfield, 6 drilling technologies for horizontal well are summarized and formed: optimization of casing program, screw drill tool types and the optimization of stabilizer outer diameter, bit selection, bottom hole assembly (BHA) for sidetracking, optimized and quick drilling in horizontal well section and KCl polysulfonate drilling fluid. These technologies are fruitfully applied in well YS9, the construction of directional and horizontal sections were completed 12.4 days ahead of schedule with shorter well construction cycle and reduced cost.

Abstract:The depth of 1500m was designed for ZK3349 in Wuzhuang iron mine of Xuchang, where the thickness of overburden layer was up to more than 400m，there were several fracture zones, the contact zone of quaternary and tertiary strata with soft and hard interbedded rocks containing large amounts of gravel and boulder. Diameter shrinkage, wall collapse and hole inclination were often encountered. The corresponding measures were taken to smoothly fulfil the drilling. The open hole drilling in overburden layer and wire-line core drilling technology in deep hole are summarized.

Abstract:The concepts of isoelectric drilling method and zero potential drilling fluid are presented. By the concept of isoelectric drilling method, zeat potential on rock surface is zero, that is, in IEP state, both penetration rate and bit service life can be improved with consequent higher drilling efficiency. As for zero potential drilling fluid, that is changing currently used Na-bentonite with zeta(-40～-35 mv)potential into bentonite with zero potential(-5～ 5 mv); changing “anion suspension system(ζ potential＞-45 mv)” of the drilling fluid into “cationsuspension system(zeta potential close to zero potential)” and changing anionic treating agents, such as filtrate reducer and viscosifier, into cationic or nonionic ones to form the drilling fluid with the corresponding performance. Drilling experiment shows that drilling efficiency can be effectively improved by isoelectric drilling method and zero potential drilling fluid. Some understandings of the relevant research are put forward.

Abstract:In order to solve the high asphalt softening point, poor dispersibility, poor lubricity at relatively low temperature and weak borehole wall stability, GFT anti-collapse and drag reduction agent was developed mainly preparing by asphalt and resin material with the softening point at 35℃. This agent exhibits its advantages of good stability and lubrication; it can effectively reduce the filtration of drilling fluid without the viscosity increasing; due to the strong adhesion ability of asphaltene particle, the agent can effectively fill and seal the microcracks and microporosity of borehole wall and bond broken rocks or particles to increase the stability. With 1% GFT anti-collapse and drag reduction agent adding into freshwater bentonite slurry, the lubricating coefficient decreases is up to more than 80%. Through field application of GFT in boreholes of ZK30-7 and ZK30-8 in Yuqia coalfield exploration region, it is proved that GFT anti-collapse and drag reduction agent has good wall protection effect in broken formation, and can significantly reduce the torque of drilling tool with its excellent lubricity being present.

Abstract:The weathered lamprophyre is unstable water-sensitive formation, wall collapse often occurs in drilling process with drilling tools sticking and burying. According to the characteristics of weathered lamprophyre formations and the problems encountered in drilling, experimental study was made on wall protection technology with flushing fluid in weathered lamprophyre formation, and PHP-CORESMART solid-free flushing fluid was developed. The flushing fluid is of strong inhibition and film forming ability being prepared with PHP, Na-CMC and CORESMART, which is applied successfully in weathered lamprophyre layer.

Abstract:Mud cooling technology is one of the key technologies in gas hydrate drilling, the low-temperature mud will restrain the decomposition of gas hydrate in the process of drilling and drill lifting, which is favorable for discovering hydrate samples. The new gas hydrate mud cooling system consists of the ethylene glycol cooler, finned tube heat exchanger, temperature monitoring & recording and anti-frost device. Frequency conversion starting mode is used for the cooler, which can reduce the generator power and the cost of fuel consumption is significantly cut down. Convection heat transfer mode is applied for mud and ethylene glycol in the finned heat exchanger with large heat-exchange area and high efficiency. The temperature of these 4 key parts can be monitored and recorded by the temperature monitoring and recording device and the mud freezing and icing clogging in the heat exchanger can be prevented by the antifreeze device. By using the heat transfer theory and fluid mechanics, the theoretical calculation for heat convection process of mud and coolant is made, the results show that with heat-exchange area of 10.58m2 and pipe pressure loss of 0.34MPa, the cooling requirements can be satisfied.

Abstract:The paper introduces MC-F04 multi functional drill rig imported from Italy about its structure and characteristics. Based on the construction practice of anchor cable construction practice for deep foundation pit, the good application effects of this rig are discussed.

Abstract:Continuous coring technology by run-through air reverse circulation DTH hammer is mainly applied in the geological drilling in dry or water-deficient areas. In order to learn the universal applicability of this technology, a series of experiments were conducted in a water abundant mining area, by local transformation of the hammer and drill pipe, the major problems of drilling, coring and water control were solved.

Abstract:Equipment well should be built under the pocket floor for the installation of monitoring equipments, while sandboils and waterspouts often occur in the construction and running process because of lax sealing. The paper introduces the system design of grouting cementing for the well under pocket floor and the construction process; discusses the grouting pressure of lateral extrusion grouting, water-cement ratio and grouting measures and analyzes the grouting principle and effects.

Abstract:The paper introduces an engineer project in Mentougou of Beijing, the construction was difficult because of the thick pebble and crushed stone layer in the site, CFG pile was selected for foundation treatment. In view of the formation conditions, construction equipments, project construction period and cost of the project, CFG pile was designed with deformation control and according to the site conditions and the characteristics of CFG pile, construction process was formulated. For the problems may arise in the CFG pile construction, the corresponding quality control measures are put forward, such as embedment of steel protective pipe and selection of appropriate rotary drilling bit.

Abstract:Taking the construction of an occlusive pile in Suzhou as the example, the paper introduces the application of drilling occlusive pile with full casing in foundation pit support engineering for adjacent subway and the main points of construction technology. The results show that the drilling occlusive pile with full casing has advantages of little influence on environment, small disturbance to the ground, rapid construction and low cost, which has a broad application prospect for foundation pit support engineering in soft soil and high water level ground of Suzhou.

Abstract:Analysis is made on the characteristics of foundation soil layers revealed in the investigation report of geotechnical engineering and based on a large amount of data from pile foundation engineering testing and settlement observation, the study is carried out on the loading performance of foundation soil around (end) pile and working properties of foundation pile. By the actual bearing capacity of pile foundation in static load test, the optimal parameters of soil for pile foundation design are derived with economic benefits.

Abstract:For the soft soil foundation under plastic drainage plate surcharge preloading, the consolidation degrees of soft soil foundation with step loading at different time are calculated and predicted by formula of vertical average degree of consolidation, which are compared to the in-situ data to analyze the consolidation degree of the foundation soil and estimate the time required for foundation soil stability.

Abstract:With the urbanization development, municipal road reconstruction project gets increasingly common and how to scientifically and effectively use the survey data in the planning period and save the cost become the focus of engineering survey. Based on the analysis on the geotechnical engineering elements of site topography and geological structure, stratum and hydrogeological conditions, rock and soil physical and mechanical properties, the stability evaluation and seismic effect and geotechnical engineering evaluation, by the comparison of the above key elements, the timeliness of the survey data is discussed to determine survey point arrangement, exploration depth and the work load of sampling and in-situ test. Take the specific project as an example, the paper discusses the key points of investigation, and points out that for survey data in planning period, the formation variation within the depth of 4.0m should be mainly considered and the focus should be on broken roads.

Abstract:The control range of total displacement is not clearly stipulated in the present correlative regulations about the acceptance test of pressure-dispersive. By comparing the tension methods of equal displacement and equal load, the study is made on the control range of total displacement of pressure-dispersive anchor in acceptance test, and some suggested values of the control range are put forward according to the practical acceptance test, which can be reference to related studies on the similar anchor acceptance tests and values determined for standard.