Abstract:In the dangerous mine project of Woxi mining area in Hunan Province, ZK9103 and ZK7304 reveal the V6 alteration layer at the bottom of Yuershan mineral vein V1. In order to alleviate the crisis of resource exploitation of Yuershan, the prospecting method combined vertical drilling at the surface and in the tunnel is used at the first to predict the resource amount of main industrial ore bodies and the position & elevation of occurrence plane, then according to the present tunnel engineering status, the inclined shaft in opposite direction to coal seam in the tunnel + laneway through the mineral vein bottom + inclined shaft bedding floor are arranged to carry out the deep development work and expand the reserves of resources for development. Good prospecting effect is received, and by which, the service life of Yuershan mine is prolonged. It is suggested to expand the exploration line in Shiliupenggong, Hongyanxi and Lijiaxi and some other ore blocks, so as to further expand the prospecting potential of V6 blind vein at the bottom.

Abstract:The formations are complicated in Xiaokou-Sikouzi salt mine of Ningxia, there is a red mudstone gypsum strata about 150m in thickness in the upper Qingshuiying Formation of the Paleogene with strong water sensitivity and poor hole wall stability, which is prone to cause collapse and hole shrinkage and results in the accidents of drill sticking and burying; the lower Najiahe Formation of Cretaceous contains mirabilite and rock salt deposits, the exposing thickness is more than 380 meters with strong water-solubility and the hole walls are easily corroded to form “big belly”with difficult wall protection and low drilling efficiency and poor coring quality. In view of the above construction problems, the research is carried out on the drilling structure, bit selection, drilling fluid and drilling parameters, on this basis, a set of wire-line core drilling technology suitable for salt mine construction is established, which is effective to maintain the hole wall stability and realize high efficiency, high quality and safe drilling.

Abstract:The well control and blowout prevention is a most important technology in small diameter core drilling in the shallow gas area, for blowout is the most serious accident in drilling construction. According to the geological core drilling characteristics, and in view of the high risks characteristics of shallow gas such as shallow buried depth, wide distribution in the block, large probability of blowout and high risk of construction, the small diameter core drilling construction technical methods in shallow gas area are worked out; according to the relevant regulations of “Implementation Details for Well Control in Daqing Oilfield Drilling”(draft for comments), and combining the geological conditions in shallow gas areas in southern Changyuan of Daqing as well as the requirement of full hole coring in geological drilling, the well control equipment configuration standard of small diameter core drilling and technical measures are established to ensure safe production and no blowout accident.

Abstract:The strata are complex in Shanggong gold deposit with multilayer fracture zones, the main formations are silicified altered shattered andesite, cataclastic gneisses and tectonic breccia, the wall collapse and diameter shrinkage are easy to occur during drilling process. In ZK322000 deep hole drilling process, not only the overburden gob broken slag formation, but also the complex strata such as fault zone water sensitive and collapse strata were encountered. In view of the strata characteristics, through the wall protection by long casing for goaf, inhibitive mud system for water sensitive stratum and high density mud for collapse stratum, the hole wall instability is successfully solved to ensure the quality of drilling.

Abstract:With the breakage of ore-bearing layer in Yangshishan gold deposite prospecting drilling in Yunnan, but coring reqirements are high, low core recovery rate and frequent downhole accidents often happen when drilling using 110mm single pipe. A set of drilling technology which combines 110mm single pipe drilling with 95mm wire-line coring is explored, the drilling difficulties in fractured ore bearing layers are solved and core recovery rate is ensured.

Abstract:In order to improve the drilling economic benefits, reduce construction risk and decrease non-production time in Rumaila oilfield of Iraq, the research on casing program optimization has been carried out. Using the design method of inner to outer and bottom to top, according to the formation pressure and combined with the geological characteristics and drilling difficulties, the structure of 3-layers casing program is adopted, the 1st spud is drilled to 6 m above the top of Dammam formation, the 2nd spud is drilled into 8～15 m of Sadi formation and the 3rd spud is completed at the depth of 50 m after drilling through the reservoir. According to the actual needs of the development of Rumaila oilfield and the string size in subsequent operation, and combined with the industry standard, the sizes of drill bits and casings for each spud are determined. Through the safety analysis on the casing string, it is found that L80 casing can not only meet the operation requirements, but also can meet the technical requirements of the safety coefficients of anti-extrusion not less than 1125, anti-internal pressure not less than 110 and tensile resistance not less than 125, and the casing strings can be put down smoothly in each spud. This technology has been successfully applied in 25 wells, the average construction period is shortened by 1533d and the average non-production time is decreased by 86 percentage. The research results show that the optimization technology of the casing program in Rumaila oilfield of Iraq has resolved many complicated problems resulted from multi-zones circulation loss, large shale collapse, sulfur-bearing water invasion, high permeability of reservoir and some othrers, so as to ensure the safe drilling under the complex geological conditions. This technology is helpful to improve the overall drilling level in Rumaila and has a broad market prospect and promotion value.

Abstract:The Qiongzhusi formation and Dengying formation of Datachang structure have good source-reservoir-cap assemblages with great potential for the exploration and development of oil and gas reservoirs. But the geological conditions in this area are complicated, during the upper formation drilling, serious leakage of Shaximiao formation, poor drillability of Xujiahe formation and some other difficulties were found. In order to speed up the drilling process in this block and solve the technical difficulties which restricted the drilling speed, by the analysis on the drilling data of the early drilling & completion and the present drilling situation, the technical difficulties probably being encountered in the drilling of upper formation of Datachang structure are clarified. According to the field practice, the technical measures of initial well deviation prevention method, large size casing cementing technology, gel cement plugging technology, bit selection are put forward, which can be guidance in drilling and cementing construction in this block.

Abstract:Leakage, diameter shrinkage, core breaking, easy hole deviation and frequent drilling accidents were encountered during the drilling construction process in Yinchang gold deposit prospecting in Pingwu of Sichuan, which made the construction very difficult. Based on the characteristics of the formation, by using wire-line coring hydraulic hammer, high density and low filtration mud fluid system, casing with drilling and some other technical measures, the drilling efficiency and construction quality are improved and downhole accidents are greatly reduced, which lays a solid foundation for the smooth drilling construction.

Abstract:In view of the high operating frequency of self-elevating drilling platforms in Bohai sea area and many times pile plug-in operation in the same blocks, the original pile holes bring serious slip risk to pile plug-in operation for self-elevating platform. By establishing the finite element analysis model of 2 types of commonly used pile shoes and using the research methods of simulation calculation and comparative analysis, the simulation research is carried out in the plastic failure characteristics of pile foundation soil, the movement law of pile foundation soil and the lateral slip force of the pile shoes while pile plugging in the positions at different distances to the “old footprints”, the force characteristics and rules of pile foundation soil and pile shoe under different soil conditions are obtained, and the influence of the “old footprints” of different positions on the slip risk of self-elevating platform is analyzed.

Abstract:Based on the deformation monitoring results of the extra deep foundation pit at Yanggaozhong Road station of Shanghai subway line 18, the deformation regularity of the deep foundation pit retaining structure is discussed from the aspects of the horizontal & vertical displacements of the retaining structure and the vertical displacement of the column pile. The analysis shows that with the layered excavation of the foundation pit, the horizontal displacement curve of the retaining structure shows a “big belly” shape, the maximum displacement point constantly moving downward, and finally being stable at about (093～107) times the excavation depth; the maximum horizontal deformation is about 330‰ of the excavation depth; the everage maximum bulging deformation is about 052‰ of the excavation depth; the column is bulged with the displacement about 091‰ of the excavation depth. All the deformation is basically consistent with the deformation trend of monitoring data in peripheral pipelines, so the above-mentioned regularities are expected to be reference for the design and construction of similar projects in the future.

Abstract:Taking the foundation pit construction of the comprehensive station area sheared by a Nantong subway station and Nantongxi Station of Shanghai-Nantong railway as an example, this paper introduces the real time monitoring of the whole process of the foundation pit enclosure and the excavation in the construction of the deep foundation pit of a reserved Nantong rail transit station. Based on the analysis on the monitoring data, the enclosure and monitoring schemes are further demonstrated to ensure the safety of subway foundation excavation and railway viaduct construction in the same period.

Abstract:For the deep foundation pit construction in settlement micro-disturbance control area, the horizontal waterproof curtain technique is more and more important in the groundwater control. The design principle of non-pressure groundwater control technology by the horizontal waterproof curtain is discussed and this technology is applied in the groundwater control design of a subway station. The pumping test and the final engineering practice result show that the design and construction of horizontal waterproof curtain have achieved the expected effects. On this basis, the suggestions are put forward for the construction technology & leakage detection methods of horizontal waterproof curtain and the real-time observation & early warning during excavation.

Abstract:Caused by the poor bit adaptability and frequent tripping, low ROP and long drilling cycle of the horizontal well drilling in Honghe oilfield severely restricted the drilling speed and efficiency. A correlation mathematical model of rock drillability and acoustic logging is established based on laboratory drillability experiments on the cores of Honghe oilfield, and the rock drillability grade profile is determined. The experiments and calculated results show that the drillability grade in the Honghe oilfield formation ranges from grade 3～6, the upper part belongs to soft formation and the lower part medium-hard formations. PDC bit is selected based on formation drillability, the average single bit footage and ROP are largely improved and the drilling cycle is shortened in the field tests and application, horizontal well drilling speed and efficiency improvement have been achieved.

Abstract:A kind of layered composite diamond bit is prepared by conventional hot pressing, the adaptability of this bit to rock layer is greatly improved with a certain universal property. Comparison tests are carried out with common bits, the drilling speed of the layered composite-structure diamond bit is greatly increased with prolonged service life.

Abstract:Based on the comprehensive recovery management of the old mining pits (wells), collapse zone and goaf left in Jinniushan mine of Muping District, this paper introduces the design and construction process of the goaf filling and grouting in detail, by which, the hidden geological hazard is eliminated and the geological environment is improved. The engineering design and the successful practice can provide good guidance and reference for similar treatment projects of gold mine collapse zone and goaf.

Abstract:Uneven settlement happened in soft foundation and road surface in a highway section of provincial road of Henan Province with channel box culvert cracking and the side slope is unstable. The accident section is divided into 4 areas for reinforcement. By grouting reinforcement of roadbed foundation, setting up a slope drainage system and improving the bearing capacity of the foundation, the traffic capacity of the road is guaranteed.

Abstract:Soil deformation in landslide and the treatment are important in the landslide control construction. Taking a landslide hazards control project in Dongyuan of Lanxi City as an example, this paper introduces a series of measures adopted for the local instability occurred in the construction process, including the analysis on the recent soil deformation characteristics and the reasons, emergency rescue measures, monitoring of emergency evacuation effects and subsequent construction plans, etc. These measures have achieved good results and provided reference for the similar construction.

Abstract:The depth of foundation pit is 265m in Liyangshengjing Plaza of Shenyang, which is a super large deep foundation pit. Because of the high groundwater level and deep dewatering depth, the construction is difficult with high safety risk. This paper elaborates and analyzes the foundation pit support and excavation, dewatering and drainage, engineering monitoring and other constructin technical measures as well as the main points of construction safety management. By means of strict safety production management, the deep foundation pit construction is smoothly completed.

Abstract:In a pile foundation project in Fuyang, the originally planned construction at the foundation pit bottom is changed to be on the ground, and nearly 14m hollow piles should be added in adition. Therefore, some related problems affecting the construction quality of engineering pile are produced, such as pile location, slag thickness at hole bottom, position of reinforcement cage, concrete quality, elevation of concrete pile top and so on. This paper introduces the construction situation, and the experience can be used as reference for similar projects.