Abstract:Herringbone horizontal well can increase bare area and output of coalbed methane reservoir. The design calculation is separately made in single awaiting drilling trajectory and main well bore trajectory, the separated well bore trajectory can be transformed into 2D trajectory for design. The optimization design model of multi-branch horizontal well bore trajectory was established according to the characteristics of herringbone multi-branch horizontal well and analysis was made on the relationship between multi-branch well bore and main well bore. The result shows that the distance and the angle between branch well and main well are in direct proportion with depth and dogleg; under the condition of fixed angle between branch well and main well, dogleg is in inverse proportion with depth.

Abstract:The process of impact hammer drilling is very complex for high non-linearity, large deformation and damage behavior. The explicit finite element code ANSYS/LS-DYNA was employed to research the transient percussive characteristic of bit' inserts impacting brittle rock with different rate of air voids. The impact forces curves of concrete and sandstone under hammer impact has been recorded. From the simulation results, the rock void rate affects variously on the transient impact force of bit' inserts penetrating rock. The impact force between bit and rock decreases sharply as the rock void rate rises. However, the transient impact force between piston and bit has nothing with the rock void rate. The physical processes such as insert penetrating rocks subjected to percussive hammer drilling are displayed visually. It is believed that the numerical simulation will become a good research method for transient impact process.

Abstract:Developed independently by Institute of Exploration Techniques, SmartMag high precision drilling guidance system can substitute the similar imported instrument. After being tested thousands of times on the ground surface, SmartMag was brought to the construction site in Turkey for its first industrial test in 2009. In the 23 intersected wells, the systematic function of SmartMag target hitting performed well with high precision and played an important role in connecting guidance of intersected well. The paper introduced the structural principle and technical parameters, and summed up the application experience and technique of SmartMag system.

Abstract:As one of the horizontal wells in the project of Turkish Beypazari trona solution mining Phase Ⅲ, H001LA is complicated in well layout comprising different main trona seams and varieties of well units styles in the design. Many difficulties encountered during the construction process such as loss of main trona seam, serious undulation of the formations, brine outflow, drilling to large cavity and formation collapsing. By the comparison analysis on the 3 feasible construction schemes, one was adopted with low cost, short construction period, high safety coefficient and successful well completion.

Abstract:The factors and the steps of drilling fluid design for geological drilling are enumerated including the formation conditions, drilling fluid types, drilling fluid material and the treatment agent, drilling fluid properties maintenance and solid control. Every item is analyzed and illustrated for the reference to drilling fluid design and field construction.

Abstract:In host strata of phosphate rock, lead-zinc mine, silver and vanadium ore and overlying strata of western Hubei, there is common existence of hard rocks. Sinian dolomite contains a large amount of silicon horizon and “chalcedony” layer formed by chemical vapor deposition, silicon content is more than 80% with dense structure, low abrasiveness and drillability of Ⅸ～Ⅹ level. By the test in drilling field, the paper described the diamond bit selection, artificial bit conditioning and diamond drilling process parameters selection; summed up the successful experience in construction practice for further resolving drilling slipping difficulty.

Abstract:The paper summarized the construction technology of uranium ore exploration in deep Shazijiang deposit and its peripheral ones in Guangxi. Difficulties of block-falling, borehole collapsing, short service life of diamond bit, wearing of drilling pipe & the joint and the borehole bending were solved in granite stratum drilling. The valuable experience was accumulated for granite stratum drilling.

Abstract:The Yunnan “hi-tech anti-drought well project” with pneumatic DTH and longitudinal slotted UPVC well pipe technology was introduced. The paper mainly presented the technical difficulties and drilling & well completion technologies of pneumatic DTH in the application for hydrological well in hard and broken bedrock, and according to the problems in drilling process, improvement measures were put forward to the drilling tool with obvious practical drilling effect. Drilling efficiency was improved in this project construction by DTH, the project cost was reduced, and the water output and quality also met the design requirement.

Abstract:Wire-line coring and percussive rotary drilling tool is a new technology combined the advantages of wire-line and percussive rotary technology. It has obvious effect in improving drilling efficiency and construction quality. By the application test, the key technical problems affected the combination application were found: floating of inner assembly and damping effect of original inner assembly. The effective solving methods were adopted, which could be the reference for future development of this technology.

Abstract:According to the deformation of an excavation engineering in Beijing, analysis was made on the basic reasons of the excavation slope deformation; and based on the situation, construction attentions in such saturated fine particle formations were considered with the solving methods.

Abstract:The paper introduces the construction process of long spiral mixing waterproof curtain interlocking pile, which breaks the construction limitation of original mixing pile and curtain of rotary jet grouting in hard soil areas with lower construction cost, and especially has advantage for the curtain in shallow excavation. Based on the engineering case of the excavation for an underground garage in Beijing, the curtain construction was proved to be an appropriate technology.

Abstract:This paper introduces the construction experiment of pneumatic down-the-hole hammer drilling technology in Beijing subway dewatering engineering; and by the comparison with other well completion technologies, the discussion was made on the feasibility and necessity of introducing this technology to Beijing subway construction with a positive conclusion.

Abstract:Qizong hydropower station was built in a high dam reservoir of canyon area, and the biggest dam was preliminarily planned to be as high as about 358m. The designed hole depth of ZK119 was 350m and located in the underground plant of left bank of upper damsite. Compared to the vertical borehole, the horizontal hole is more difficult in construction technology with higher hidden danger and higher requirements of drill pipe and drilling equipment. The construction point of horizontal excavation is hole deviation control, and taking the example of horizontal hole ZK119, the paper elaborated the horizontal hole drilling technology in the principles of horizontal drilling technology, technical features and the measures of deviation control.

Abstract:The principle and characteristics of freezing construction is introduced and the situation of freezing borehole of 1# auxiliary shaft of Liutangfang iron mine is described. The paper analyzed the difficulties and the technical measures in the engineering construction, introduced the attentions and steps in the construction and summed up the operation.

Abstract:Foundation collapsibility is one of the factors that affect the foundation stability in loess area, and is also the major form that causes the building damages. Analysis and introduction were made on the application of composite foundation treatment methods and the technical effects in Xi’an City. The paper demonstrated the application of composite foundation treatment methods in collapsible loess ground, which can eliminate part or all collapsibility in collapsible loess to improve the foundation bearing capacity and decrease the ground deformation.

Abstract:High viscosity silt soil strata have been often encountered in trenchless engineering. Great shear stress is needed to destroy the soil mass, thereupon many project accidents happened such as too large torque of drill pipe, difficult guided drilling and hole reaming with construction delay. In this paper, by the laboratory experimental study and the analysis on the mechanism molecular structure, a common disaccharide organic compound was introduced, which was applied in drilling fluid to effectively solve the high torque for drilling in viscosity silt soil strata.

Abstract:As a main geological hazard, dangerous rock is multiple and frequent phenomenon in the Three Gorges reservoir area, which is divided into falling, overthrowing and sliding unstable. The comprehensive treatment of dangerous rock includes removal, supporting, anchoring, intercepting, sealing, grouting, seepage and protection network. Controlled blast includes cavern controlled blast, deep hole controlled blast, smooth blast, pre-splitting blast, short hole circulation controlled blast, and soundless breaking and protection network, all suitable to dangerous rock elimination. According to the types of dangerous rock, different controlled blast and comprehensive application measures were adopted to protect patent rock and stabilize the rocks for emergent danger elimination.

Abstract:The scientific of risk index system is the premise for effective operation of risk evaluation model. In order to establish the index system for risk evaluation model, the paper proposed a set of index system framework based on analytic hierarchy process. By introducing the modern project management thought of “three controls and two managements”, five major criterion layers were created. Moreover, expert group was organized for each criterion layer. By using two-stage research routes, sub-criterion layers and index systems were established for five criterion layers respectively. The new risk index system has been applied in a slope engineering construction.

Abstract:The rapid growth of the economic promotes the demand for mineral and energy resources in China, which is the reason that the drilling projects increase every year. Pipe sticking occurs frequently in the complex formations. Jar is often used to solve the pipe sticking accident in oil and gas drilling; however, in the small-caliber geological drilling, the jar could not work as usual, new kinds of jar are necessary to be designed. This paper introduces a hydraulic jar with spring-loaded valve, which was designed for serious pipe sticking in Ukraine, and this structure could not only ensure the work reliability, but also improve the efficiency of solving the pipe sticking by its high-frequency impact power. The mechanical while-drilling jar designed for the areas where pipe sticking often happens can make sticking unfreezing in first time to avoid the further accident and effectively save the time of failure treatment.

Abstract:This paper introduces the development status of high-voltage pulse discharge technology and describes the mechanism, characteristics and new process of pile formation. This pile formation method has special advantages with high bearing capacity and economic benefits, and the application prospect was discussed.