Abstract:The borehole WFSD-4S of Wenchuan earthquake fault scientific drilling project is a shallow supplemented hole through Wenchuan earthquake main slip band for further understanding the main slip of the Wenchuan earthquake to get more comprehensive drilling data, which is located near the surface rupture zone by the fourth hole in the Nanba region. The paper introduces the key technology and measures applied in the borehole WFSD-4S of Wenchuan earthquake fault scientific drilling project for the difficulties of complex geological conditions and low core recovery. The results of its application were analyzed and summarized; the detailed discussion was made on the formation conditions, the construction process, coring drilling tools, drilling fluid technology and accident treatment, which will provide important reference for the selection of reasonable coring technology in future complex formation drilling.

Abstract:The influence of casing can not be ignored for evaluating the transmission effect of EM-MWD signal, and it is difficult to analyze this effect with mathematical models because of the casing's extremely complicated effects. Therefore, modeling and stimulation of EM- MWD signal transmission in the casing were made by ANSYS finite element software to analyze the influence rule of casing on EM-MWD signal transmission in the aspects of ground current density and ground receiver voltage. The stimulation results show that the casing plays a guiding role to the signal when insulation nipple is out of the casing, and conversely, the casing has a shielding effect on the signal; low resistivity drilling fluid has a great influence on EM-MWD signal transmission in the casing.

Abstract:In the littoral placer resource investigation in the east of Hainan Island, good results were achieved in the application of cord hammer coring shallow drilling technology for 20m shallow drilling. The practice has proved that this shallow drilling technique is an effective means to obtain the shallow geological material data, verify the underground information inference and interpretation for the final delineation of the ore body, reserves calculation and grade assessment. This paper introduces the shallow geological drilling technology with such a simple structure and small disturbances along with its application in production.

Abstract:In the fracturing treatment process of shale gas reservoir with low permeability and low porosity, pH value of fracturing fluid system directly affects the formation and stability effects of fracturing, it also affects the anionic surfactant fracturing fluid a lot in viscosity, surface tension and shale swelling inhibitory. In this paper, by changing the concentration of the anionic surfactant, basic performance changes of fracturing fluid system in different pH conditions are measured. The experiment results indicate that the SDBS viscosity of SDBS fracturing fluid system increases with pH increase first, then decreases, and reaches the maximum when pH is 9. The best ability to reduce surface tension of the system is with pH 5. The expansion volume of the shale increases gradually with the increase of pH, and reaches the largest when pH is 7; along with the further increase of pH value, shale expansion decreases first and then increases, the expansion capacity is the smallest when pH is 9. When the pH value is invariable, SDBS can inhibit the shale expansion most in the state of critical micelle concentration. In this paper, the effect of pH value on the performance of SDBS fracturing fluid is analyzed from the chemical micro point of view, which is beneficial to the optimization of SDBS fracturing fluid system formula.

Abstract:Since the breakthrough of deep natral gas exploration in well 1 of Qingshen gas field, Daqing oilfield has stepped into the stage of both oil and gas exploration and development. For the low drilling technical level, only 123 wells were completed during 2004—2010 with average well depth 4118m and drilling cycle 141d. Since 2011, by using the experience of speed increasing technology for deep drilling both in China and abroad, and based on the rock features, the speed-raise countermeasures were worked out. By the well structure optimization, high-efficient PDC bits selection and independent-research on new tools, deep drilling level was greatly improved. During 2011—2013, 19 wells were completed with everage depth of 4075m, drilling cycle was shortened 48.6d. According to the existing well head pressure, the causes were analyzed with a series of technical research; the matching cementing technology of gas channeling prevention was formed to provide the support and guarantee to increase reserve and production of deep natural gas.

Abstract:It has been a difficult problem to make up drilling fluid with stable performance under saltwater condition to keep borehole wall stability in the drilling construction in Gobi of Xinjiang. By the selection of drilling fluid materials and the test studies in different work areas, MBM-GTQ saltwater drilling fluid system was determined for use with good application effects for deep hole construction and accident treatment in intensily altered strata in Pobei Cu-Ni mine of Ruoqiang County. The practice proves that MBM-GTQ saltwater drilling fluid system is an effective scheme for the broken altered strata there.

Abstract:With an engineering case of ultra-deep foundation pit in Wuhan, based on the common-used deep foundation pit design scheme, the discussion was made on the overall design scheme selection, the selection and design of foundation pit maintenance system, selection of supporting system, foundation pit dewatering method, earth excavation scheme and support-changing plan. The final design scheme is underground continuous wall enclosure 3 internal supports confined water dealt with tube well dewatering.

Abstract:Based on the characteristics of engineering geology and hydrogeology conditions and according to the surrounding environment, the study was carried out on a deep foundation pit supporting scheme which was under complicated environmental conditions. The paper introduces the supporting technology for foundation pit with diaphragm wall and inner bracing; and the calculation was made by the design software of deep foundation pit supporting structure to provide reference for the similar deep excavation construction.

Abstract:The geological conditions were analyzed for the foundation pit engineering of Passenger Car Institute of First Automobile Group in Changchun, the analysis and demonstration were made on the supporting scheme and the soil nailing wall support scheme was designed. The optimal design of soil nail inclination angle was made within a reasonable range with single factor analysis method and the influence law of soil nail inclination angle on foundation pit slope stability was obtained. The practice shows that by this soil nailing wall supporting scheme, the engineering works was completed with short-term efficiency and investment saving; by the optimization design of soil nail inclination angle, the construction safety was greatly promoted with original project construction cost. This practice provides conference to the application study on soil nailing wall support of foundation pit engineering in Changchun.

Abstract:The depth of the foundation pit area 1 of Runhua Globe Center reached 18 meters, and it was constructed by using cast-in-situ bored piles and inner bracing structure. Vertical settlement and horizontal displacement at the surface around the deep foundation pit were monitored during and after the foundation engineering construction. By the completion of the construction, the subsidence and horizontal displacement reached the stable values of 25mm and 40mm respecively, the supporting effect was coincided with the design requirements. However, monitored values increased suddenly just at the time after the third excavation and before the second support completion and the growth rate were slowly decreased until the second supporting structures were completed. It is advantageous to reduce the deformation of foundation pit and improve the supporting effect by increasing the designed elevation of the second supports.

Abstract:This paper introduces the stress-dispersion and self-locking type pre-stressed anchor rod technology used in danjiangkou dam heightening project. The special reaming tools and self-locking type anchor with reliable performance and reasonable structure were developed to complete the difficult 50m high precision drilling in the project. With this anchorage technology, stress concentration in the inner anchorage section was improved; ordinary anchor pre-stress transmission to base through bonding between inner anchorage body and hole wall was changed by the use of self-locking inner anchors designed for the hole enlarged sections with dispersed pressure directly applying on the base at different depth. In this case, the anchoring force will not lose along with bond force decreasing, long-term anchoring can be ensured.

Abstract:Longitudinal vibration of drill pipe has great influence on drill pipe failure. By the analysis on the longitudinal vibration of drill pipes within the length of 2000m with ANSYS software, the intrinsic frequency of drilling pipes with different specifications, drill collars and drilling strings with different length as well as the first 5 natural vibration modes of longitudinal vibration of drill string are obtained. The results show that the intrinsic frequency of drilling pipe is slghtly affected by the drilling pipe specifications and drill collar length, but by drill pipe length a lot.

Abstract:According to the difficulties for rotary drilling rig in large diameter rock-socketed pile construction in hard rocks, cluster DTH hammer is matched as the solution. JSQ-Z positive circulation and JSQ-F reverse circulation cluster DTH hammers were designed, 3 kinds of construction methods and drilling tools matching scheme are presented, which makes large diameter rotary drilling in hard rocks more rapid, efficient and economical.

Abstract:Reliable sealing structure is the key to use the reverse circulation drilling technology for large-diameter reverse circulation DTH and is also the design point of large-diameter reverse circulation DTH. The sealing structure of existing large-diameter reverse circulation DTH is designed on basis of BHA body structure. A double sealing method at bottom and entrance of drilling hole is proposed in this paper, based on which as design principle, φ710/311mm cluster reverse circulation DTH and entrance sealing device were developed for reaming, the field test was made matching with φ127/70mm double-wall drilling tool, continuous reverse circulation effect was realized, the average ROP was 2.1m/h which was 2.6 times of the ROP of roller bit used in the same hole. The test results show that the double sealing method at bottom and entrance of drilling hole is feasible and it is worthy to be popularized.

Abstract:Solid-control device is widely applied in petroleum drilling and has been implemented in series, standardization and specialization. Geological core drilling is different from oil drilling in depth, diameter and process. The GK-15 mud solid-control device for geological core drilling is developed on the basis of the comprehensive characteristics of solid-control device for petroleum drilling and combined with the requirements of geological core drilling technology, the vibration sieve, cleaner and centrifuge are connected through a pipeline to form a closed mud solid control device to achieve of slurry preparation, circulation, solid control and reserve. The paper introduces the structure and parameters of GK-15 mud solid-control device for and sums up the application conclusion.

Abstract:In deviated well drilling, drill stems will naturally be pressed close to the borehole wall on the bottom side owing to the gravity with static frictional resistance produced, which will further evolve into backing pressure and lead to toolface, lower ROP and reduced drilling footage in a single trip; if not timely moving about the pipe, sticking accident is likely occur and even more with well abandoned. Therefore, friction reduction and backing pressure relieving become important parts of safe drilling. The magnitude of friction is decided by the component force and static friction coefficient of drill strings weight in borehole trajectory normal direction. In sliding drilling, some ways such as adding lubricant into the mud or making a short tirp (for borehole dressing) were adopted to reduce the static friction coefficient for the purpose of reducing friction and relieving backing pressure. In term of the classical physics, the static friction is greater than sliding friction; therefore, backing pressure relieving can be achieved by transforming the static friction into slide friction. In this paper, the application effects are evaluated based on the cause analysis on the friction, the mechanism of hydraulic oscillator and its application in Sulige gasfiled and Yumen, Daqing as well as some other oilfields. And the matters of attention in the use of hydraulic oscillator are discussed through the field test in Ya K1-7 well of Yumen oilfield.

Abstract:By the analysis on the main technical parameters of CS1000P6L drilling rig, it is thought that core drilling construction is feasible in 0°～45° angle range; after further study on the power head, a main part of the drilling rig, a specific project was selected for the application experiment, the problems found in the course of the experiment were carefully analyzed and solved, so then the performance reliability of the drilling rig working under the conditions of 0°～45° angle was verified. Through the analysis on related matching facilities for horizontal hole construction, not only the operation platform and the drill pipe & drilling tools setting were arranged but also the displacement control of the rig was solved.Practice has proved that CS1000P6L drilling rig can realize core drilling operation in 0°～45° angle range.

Abstract:Along with the development of Bohai oilfield, deep wells, extended-reach wells and some other high difficulty wells operation are greatly increasing. It is an inevitable requirement to run liner into the well or land sand screen after well completion. But this operation is generally carried out in deep well section with great difficulty, reaming becomes the main technical measure. The paper introduces the landed single ball reamer about its structure composition and working principle, elaborates the application in reaming while drilling and reaming after drilling (back reaming and underreaming) with example and analyzes the application effects in different operation models.

Abstract:This paper introduces a design plan of the combined reinforcement of high slope deformation based on pre-stressed anchor cable and the cantilever pile (wall). By the supplementary investigations of the slope geological lithology and the stress analysis on the internal force of slope protection pile structure, the causes of the high slope deformation and the local cracks of the pile were found out; the reinforced cantilever pile (wall) was designed with pre-stressed anchor cable for use. After a long time monitoring, the maximum displacement of pile head is accumulative 30.1mm in 3 years, which is less than the national regulations. It shows that the design of pile-anchor reinforcement if safe and reliable and the successful experience can be reference for the similar project.

Abstract:Many landslides in Three Gorges reservoir area have large deformation during the drawdown of reservoir water level every year. In this paper, based on the landslide structure and deformation characteristics of Zaozishubao in Three Gorges reservoir area, the formation mechanism and stability situation are analyzed; groundwater seepage fields are simulated by using finite element method when the reservoir water level falls, the pore water pressures are used for the analysis on limit equilibrium of landslides, the influence mechanism and laws of the drawdown rate of water level on accumulations’ stability are discussed. The analysis results showed that the landslide was formed by accumulation and transformation after sliding and bending failure of rock mass in the early stage, it is now in stable condition, but it is predicted to be in unstable state when drawdown rate of water level increases. The stability coefficient of landslide will decrease along with the reservoir water level falls, the faster water level drops, the greater stability coefficient decreases. Intensive rainfall has greater influence on the stability of landslide than the water level drawdown. The anti-slide pile reinforcement measures are proposed to improve the stability of landslide, the research methods and results have good reference value for the evaluation and treatment of the landslide.