Abstract:Exploration and production wells need to achieve the dual purpose of accurately obtaining hydrogeological parameters and solving the problem of drinking water for the people. Therefore, when rotary drilling technology is adopted, the flushing fluid is required not only to have basic wall protection and anti-collapse functions, but also to minimize the impact on formation permeability, and also to have good environmental protection.. According to this special requirement, a new PA-1 type solid-free flushing fluid solution was developed, also, the permeability test, SEM and sand ball immersion test were used to evaluate and analyze the flushing fluid in the laboratory, The results show that PA-1 solid-free flushing fluid has little influence on formation permeability and strong ability to prevent collapse, Which comprehensive performance is superior to the conventional flushing fluid system; In addition, the acute toxicity test of Chinese rice shrimp showed that it was safe and non-toxic. Therefore , a large number of laboratory experiments and field applications show that PA-1 solid-free flushing fluid has excellent performance,which can provide a reference for the selection of flushing fluid in Exploration and production well construction in the future.

Abstract:The Tibet Autonomous Region Jiama Copper Polymetallic Deposit 3000m Deep Scientific Drilling Project is the first 3000m scientific drilling project for solid mineral survey in the Qinghai—Tibet plateau area. The project is executed to characterize in detail formation alteration and mineralization information within 3000m， and provide a solid foundation for the study of the metallogenic theory and the establishment of the deep exploration model. In view of the project purposes， and taking into account of the site inspections and the geology in the mine， HXY—8VB type core drill rig with the K type derrick is proposed， together with the 5—tier borehole structure and multiple drilling processes including conventional core drilling， wireline coring and reaming and conventional wireline coring, so as to provide a guarantee to improve drilling efficiency and drilling quality．

Abstract:The gas lift reverse circulation process has the advantages of high drilling efficiency, strong cutting carrying capability, good loss prevention effect and long bit life, etc., and can also increase the productivity of liquid minerals. However, it is generally believed that the suction action of gas lift reverse circulation drilling will produce negative pressure, which is not conducive to the stability of the well wall and not suitable for application in loose formations . In this paper, by calculating the hydraulic parameters of the gas lift reverse circulation drilling annulus, and discussing the well wall stability and applicability of gas lift reverse circulation drilling from the aspects of annulus pressure, drilling fluid flow state and flow velocity, it is pointed out that suitable combination of the drilling string and conditioning of drilling fluid properties can make the gas lift reverse circulation process more adaptable to different formations.

Abstract:Drilling on water, especially on rivers where the water flow is relatively fast, is more difficult than land, with difficulties in construction, high risk factors, and low drilling efficiency. Large hydropower stations are often selected among alpine valleys. The early exploration conditions are extremely bad, and it is extremely difficult to transport on the water drilling site. River core drilling is a technical method for effectively verifying the thickness of the river bed cover, which is usually encountered in hydropower station exploration. This article introduces the construction and installation of the oil drum raft used in the offshore drilling construction of the project and the calculation and verification of various parameters, the selection of anchoring steel rope and strength verification, the optimization design of the river surface transition equipment, and the protection casing The key technologies such as access method and verticality check, oil drum raft transfer, overburden hole formation and coring technology, and hard and strong grinding bedrock drilling technology provide reference for similar projects in the future

Abstract:In view of the deep and high dip strata in Xiangxi Gold Mine, where the traditional deviation prevention methods, such as the packed hole drilling string, the pendulum drilling string, cannot guarantee the borehole verticality , the mud motor was used with MWD for the first time to drill a pilot hole, and then pneumatic DTH drilling to quickly ream it to the large diameter filling borehole, achieving good results. The mud motor can provide better directional drilling with the deviation controlled within 8.67m.

Abstract:According to actual drilling wells in Gucheng area, there are many technical difficulties in drilling "black quilt" strata, H2S, stuck drilling, well leakage, overflow, well collapse and formation pressure and temperature, which lead to long drilling cycle and high drilling cost in this block. Geological characteristics in this paper, according to the ancient city area, combined with the drilling purpose of well Gucheng 601 and well completion method, the comprehensive consideration of well bore such as formation pressure, will seal point, on the premise of ensuring safety and quality, optimize well structure of Well Gucheng601, according to the real drilling verified that the design is reasonable, for optimize well structure of Well Gucheng601 well bore structure design provides a new way of thinking.

Abstract:During the drilling of several geothermal wells in Chongqing urban area and surrounding villages and towns, conventional drilling methods cannot guarantee the borehole inclination after entering the Triassic Xujiahe Formation to reach the standard due to factors such as the large formation dip angle, frequent lithological changes; thus affecting the success rate of obtaining geothermal water resources. When directional drilling tools are used for deviation correction drilling, the selection of the tool face and borehole azimuth change value of the drilling tool has a particularly important impact on the borehole trajectory. At the same time, when the tool face of the drilling tool is determined, drilling a new borehole is also influenced by formation lithology. In order to smooth the well trajectory and avoid the creation of dog legs, this paper analyzes a geothermal well drilling case with directional technology , sums up the field experiences, and optimizes the controllable factors of the directional drilling well trajectory.

Abstract:The inner tube assembly often falls into the hole due to breaking off of the core drilling string. This paper analyzes the existing fishing difficulties and the measures to be taken, and describes the design of two sets of fishing tool in view of the actual situation of two different drilling holes. The inner tube assembly which was completely exposed in the hole was successfully fished out of the hole, avoiding abandonment of the borehole, saving drilling time, and reducing economic loss. Practice has proven that these tools are effective.

Abstract:The purpose of the real time acquisition system for drilling parameters is to provide visual real time drilling parameters to drilling technicians and managers so that they can grasp drilling conditions all the time. Drilling parameter acquisition is performed in such a way: physical parameters such as pressure, speed, displacement , flow, liquid level are sampled with sensors, and then converted and processed into drilling parameters with the matching hardware and software equipment for visual display on the human computer interface. Depending on specific working conditions in the field, the system can use Internet, GPRS terminal or Beidou satellite terminal to transmit wirelessly real time engineering data to the remote server while users can view real time or historical engineering data on site through mobile phones or computers. Using this system can prevent and reduce drilling accidents , provide data support for accident handling, and provide basic data for drilling informatization and automation.

Abstract:At present, plastic casing and MTC material are used for cementing in sandstone uranium mining. This paper discusses the particularity of plastic casing cementing. It is not effective to detect the quality of plastic casing cementing with the instruments that test the quality of steel casing cementing. Thus, a JMTC—1 logging tool using the principle of measuring ultrasonic damping parameters was developed. The instrument can be applied to the cementing quality detection for casings of various materials. This paper introduces the design principle of JMTC—1 logging tool and its application in plastic casing cementing quality detection.

Abstract:The change of water content in rock and soil layers is one of the most important factors inducing geological hazards of landslides and debris flows. In the past, the measuring principles, such as the tensiometer method, resistance method, neutron method, capacitance method, gamma—ray method, optical measurement method, TDR method, have been used to measure water content in rock and soil layers. Those methods have some disadvantages such as low accuracy, great personal harm, great influence by weather, expensive electronic parts. The FDR—type automatic monitoring instrument for multi layer water content in rock and soil layers of the landslide body uses the electromagnetic frequency domain reflection (FDR) tubular water content sensor for measurement, and carries out remote water content data acquisition and wireless transmission with the wireless communication acquisition and monitoring instrument. The automatic multi layer water content monitoring instrument for landslide rock and soil layers has the characteristics of compactness, large measurement range, quick response, high sensitivity, high precision , corrosion and moisture resistance, which has promoted the progress on early warning and monitoring technology for geological hazards.

Abstract:Taking Liudong New District of Liuzhou City as an example, the flood interception ditch and slope retaining project is introduced with analysis of a section of high slope with elevation difference of 25m. Stability evaluation and residual sliding force calculation is conducted for the landslide using the broken line sliding plane transfer coefficient method of limit equilibrium theory. Discussion is made on the design approach for the three layered anchor cable pile sheet retaining wall. The internal force of the anti slide pile body is calculated by both the landslide thrust method and the Coulomb earth pressure method with the structural plan of the pile sheet retaining wall selected through analysis of the internal force of the pile body. The slope protection plan above the retaining wall, the monitoring plan and suggestions during and after high slope construction are introduced. It provides reference for the treatment of high slope landslides in the future.

Abstract:The foundation pit support works for the Wuhan Nanguo Center first phase project was constructed using the top down construction method, where the surrounding environment was complex, and the sand layer at the site is thick. The technical requirements for foundation pit design were high, in particular, the verticality of the diaphragm wall and column pile of the support structure was high with deep rock embedment. The soft and hard alternate formation tended to produce deviation during construction with low rock penetration efficiency. In view of the major and difficult points in construction, measures were taken from the aspects of equipment selection, process selection, bit selection, etc. to solve the difficulties in the construction of the super deep and large foundation pit support structure by the top down method. The approach to solving the problems was introduced, and significant results were achieved with the quality meeting the relevant technical requirements.

Abstract:The foundation pit flooding accident of the Jiangsu Disability Rehabilitation Center project was caused by the improper previous dewatering plan design and quality control of dewatering construction. In depth analysis of the stratum data about the project location during the accident handling process showed that this area is a typical dual geological structure of the Yangtze River floodplain where the main aquifer is the thick sand layer. With fully consideration of the characteristics of the aquifer such as great thickness and large permeability coefficient in this area , the number and depth of dewatering wells was properly planned. Through abandonment of unqualified dewatering wells, and strict control of the construction quality and operation management, the water flooding accident at the foundation pit was successfully resolved. This article details the accident history and treatment process so as to provide useful experience for similar projects.

Abstract:The change of soil strength and deformation parameters caused by the freeze thaw cycle is one of the important issues with engineering works in the cold area. In order to investigate the change of strength and deformation parameters, with the saturated silty clay samples taken after and before the freeze thaw cycle as the research object, the triaxial shear test after consolidation and drainage, triaxial isotropic compression test and elastic modulus test were carried out to analyze the effects of freeze thaw cycles on soil strength and deformation parameters . The research results can be used as reference for the treatment of frost damage in engineering works and also as testing data for numerical simulation.

Abstract:In this paper, the causes of leakage to the foundation pit is illustrated in detail by the example of a construction site in Wenzhou City, where drainage and plugging technology was used to treat leakage to the foundation pit. A diversion pipe was used to drain the leakage outlets to relieve the water pressure in the soil layer of the leakage site and some surrounding areas, and to improve the success rate of leakage stoppage. Then, double liquid grouting was used to cut off part of the water flow path so as to reduce the water flow from the leakage outlets; and to reinforce the foundation pit. The results showed that drainage and plugging provided efficiency, accuracy and effectiveness in the field, with 57 leakage points in the foundation pit effectively treated.