Abstract:The casing heater can also maintain the wellbore formation while maintaining the stability of the pore wall to prevent the formation of secondary hydrates in the well during the hydrate production process. In order to analyze the influence of daily water production, gas-water ratio and heating power on the temperature distribution in the well formation during the hydrate production process, the heating process was simulated by COMSOL Multiphysics. The simulation results show that the effect of water production rate on the heating effect is obviously greater than the heating power. The heating power mainly affects the formation temperature of the near-well section, and the gas-water ratio mainly affects the heating radius. The numerical simulation is used to analyze and evaluate the heating effect of casing heater, which is of guiding significance for the economical and efficient mining of natural gas hydrate.

Abstract:The well CGSD-01 of Donglihu in Tianjin is a geothermal exploration well. The design depth of the well is 4000m and the completion depath is 4051.68m. In order to clean up the blockage of aquifer in the drilling process, the well is flushed by three methods, and pumping tests are carried out twice. This paper mainly describes the well washing and pumping test technology and process of the well CGSD-01, in order to provide useful reference for similar research in the future.

Abstract:The geological borehole is often designed as a largeangle hole to achieve the purpose of prospecting and orecontrolling according to the stratum and ore body characteristics of the Jingcun gold deposit in Deqing County, Guangdong Province; thus leading to excessive doglegs in drilling. The borehole deviation rule and characteristics were summarized through collecting and summarizing the early drilling data in the mining area, and primary directional drilling was applied together with “one mother hole with multiple laterals”, resulting in good effect with the excellent drilling quality, improved drilling efficiency, and significantly reduced drilling construction costs. The article focuses on the primary directional drilling design and the dogleg severity control during the drilling process. It proposes a solution to the problems encountered in the drilling, and some experiences and understandings of drilling of large angle holes are summarized.

Abstract:Shale gas formation is characterized by high hardness, high brittleness, high drillability, leading to low PRM, less footage per run and low core recovery. Based on the field practice of Quancan Well-1, this paper sums up the experience of large diameter one-pass well coring and completion. In the process of drilling, the drilling parameters were adjusted reasonably, and the core drill bit and coring accessories were specifically selected with the coring run increased to meet the relevant requirements of the sampling test. The core drilling efficiency was improved by combining rotary table + PDM drilling, and the drilling cost was reduced by a certain extent.

Abstract:The outrush water in tunnel bore hole brings great drilling operation problem to conventional small diameter coring operations. It was found that the core could get out of the hole with the high water pressure inside the hole combined with the drilling operation of the tunnel hole to explore Ia ore body of Shuiyindong Gold Mine. Thus, the core-uplift-coefficient ξ was put forward; its physical meaning is that under the action of water pressure and buoyancy at the bottom of the hole, the core overcomes its gravity and the friction force to automatically rise. And its practical significance was discussed in combination with the practical parameters of bore holes. When ξ is greater than or equal to 1, theoretically the cores at the bottom of the hole can rush out of the hole with the gushing water. When ξ is smaller than 1, the cores cannot rush out of the hole and drillers should pull out the drilling strings to obtain the cores. By calculating the ξ of the ore layer and combining with the integrity of the actual stratum, it helps the drillers to control the proper drill footage to make sure the ξ≥1. So the core in the drill hole can be automatically lift up from the bottom of the hole. The core-uplift-coefficient ξ not only can provide theoretical guidance for the high pressure water hole in the surface or tunnel drilling holes, but also has certain practical significance.

Abstract:Only a few boreholes in Beijing Daanshan Coal Mine were controlled to the level of +550m. In order to explore the occurrence conditions of deeper coal seams and improve the magnitude of order of resource reserves, a ZDY1000G full hydraulic tunnel drill rig and S75 wire-linecore drilling technology were used to carry out deep hole drilling in the adit. The test drilling depth in the tunnel was 505.17m. Subsequently, from 2012 to 2014, the total drilling amount was 8237m, resulting in an increase in the resource reserves by 18.777 million tons through exploration . On the one hand, the deep hole drilling technology can accelerate the exploration of deep horizontal coal seams, and define the occurrence condition of deep horizontal coal seams, which provide reliable geological data for the development of the project. On the other hand, it also reduces the cost of tunnel exploration and improves the efficiency of development. In this paper, the deep hole drilling in the tunnel is introduced.

Abstract:Well Longping-1 is the first horizontal well drilled in the bedrock formation of Songliao Basin in Daqing Oilfield. The designed MD is 4532.72m (TVD: 3111.50m). The exploration purpose of the well is to explore how to greatly improve the natural gas productivity of the weathered crust bedrock reservoir in the ancient central uplift zone through horizontal wells. In order to tackle the potential difficulties and risks in the process of drilling, optimization was performed of well structure design, well trajectory design, drilling parameters, and bit selection with the ROP enhancement experiments. The full well average ROP was 5.15m/h with an significant increase by 45.89% compared with the designed value, which provides valuable experience for exploring the basal structure in this area.

Abstract:The oilfield of Xunyi-Yijun is located in the south of the Yi-Shan slope in Ordos Basin and is in its early stage of development. The formation unconformity contact cracks and stress cracks were formed due to the sedimentary environment of the Yanchang group of Triassic and the late tectonic movement, which makes it easy to lost circulation in the drilling and cementing process, resulting in insufficient return of the cement slurry; thus, the upper well section had not been effectively sealed. In this paper, the main factors for leakage are investigated by studying the geology, the drilling process and the drilling equipment, the slurry column structure and cementing technology in the oilfield. In order to improve the sealing quality of the oil and gas layer, the paper puts forward the anti leakage measures; optimizes the cement slurry formulation, which makes the slurry provide certain plugging performance; and modifies the slurry column structure and cementing process according to the “kill and seal” balanced cementing concept. After adopting the technical measures, the cement slurry return height and cementing quality of the oil and gas well in the job area met the requirements of the later fracturing treatment.

Abstract:Well BZ34-5-A was originally a high yield well, but a series of complex problems occurred in the later period, which made the well unable to produce. In order to restore the well productivity, comprehensive treatment of the low efficiency well was needed. Based on the analysis of drilling and completion data in the early stage of the block and the problems in the late stage after it was put into production, the final operation scheme was determined through comparison of the comprehensive treatment methods. The solid free drilling fluid with strong inhibition was used to for sidetracking, the perforation pipe was run into the open hole section without cementation, and then the perforation pipe was perforated with wireline perforation to complete the treatment of the inefficient well safely and quickly; thus protecting the reservoir to the maximum extent and restoring the productivity of the inefficient well. At the same time, the treatment cost was greatly reduced, which provides a good reference for similar low efficiency wells in nearby blocks.

Abstract:In view of the problems of the mechanical bell bottom drilling tool such as the separation of hole reaming from soil collecting and cleaning, complicated process, difficult cleaning of bottom settlements, low drilling efficiency , uncertainty in ensuring the quality and accuracy of reaming, the soil collecting bell bottom drilling tool based on the electro mechanical hydraulic integrated system has been developed. This paper mainly focuses on the drilling technology of soil collecting and bell bottom drilling, the mechanical hydraulic electric control system design for the soil collecting bottom expanding drilling tool, as well as testing of the electro mechanical hydraulic integrated system. The results show that the soil collection bell bottom drilling tool integrates functions of the soil collecting and the reaming to improve the accuracy of the belled diameter and the reaming precision, reduces the drilling procedures and improves the work efficiency, meeting the requirements of belled piles on the rotary drilling process and realizes the intelligently under reamed drilling.

Abstract:In order to solve the problems of poor drillability and slow ROP, reduce the friction drag in slide drilling of the horizontal section, and improve drilling efficiency in drilling horizontal wells in hard formation for oil and gas, a fluid powered efflux hammer was developed for horizontal drilling through the analysis of the tool working principle and the improvement of the structure and parameters. On the basis of bench tests, the performance parameters , drilling tool assembly and rotary percussive drilling parameters were further optimized, and the field tests for horizontal drilling were carried out. The results of field tests showed that the fluid powered efflux hammer has a remarkable effect in increasing the ROP over the horizontal well section, so it is worth further research. However , the failure of the tool in the horizontal section affects its effect in improving the ROP. In this paper, the problems of the tool are analyzed theoretically and experimentally, with the improvement plan put forward.

Abstract:The core barrel with roller bits is a common drilling tool for rotary drilling into rock. In order to solve the problem of difficulty and low efficiency in rock drilling, this paper analyzes the movement mode and rock breaking mechanism of the core barrel with roller bits. In the structural design of the core barrel with roller bits, the focus should be put on the arrangement and placement angle of the roller bits, and the selection of the carbide teeth, as well as the locking method of the replaceable rollers and the structural characteristics of the reaming core barrel. This paper presents the structure of core barrel with roller bits suitable for rotary drilling which has achieved good results in the production test.

Abstract:The curtain grouting project of No. Ⅰ ore body of Great Wall Gold Mine in Qian’an is a large scale water cut off project, characterized by its extensive scope, large quantity of designed boreholes, complex geologic conditions , large volume of grouting and long construction period. This paper elaborates the principle and procedure of curtain grouting, summarizes its construction features and rules, and analyzes its application effect.

Abstract:In the Jinan Dongshefang deep foundation pit works, three kinds of support methods were used in the same support project: the pile anchor, the cantilever pile, and the composite soil nailing wall. The design and monitoring of the foundation pit support are introduced. The monitoring results show that all three support methods can meet the safety requirements of the foundation pit and meet the design requirements; indicating that the three support methods applied to the same deep foundation pit worked very well, saved the project cost, and cut short the construction period. Comparison of deformation demonstrates that the pile-anchor support has the best effect on controlling the deformation of the slope, followed by the cantilever pile; while the composite soil nailing wall is the most disadvantageous.

Abstract:This paper presents the calculation formula of earth pressure based on SMP failure criteria in the active zone, passive zone, and different soil and water conditions. The calculation results based on SMP failure criteria of Shanghai Center Tower is compared with the measured data and the calculation results of Rankine’s earth pressure. The results show that compared with that of Rankine’s earth pressure, the earth pressure based on SMP failure criteria is more consistent with the measured value, and provides some safety margin.

Abstract:Under the geological conditions of soft and water rich sand, the shield receiving process is one of the major risks in shield tunneling. It is also one of the most difficulties in the whole work. Based on the shield receiving operations in the soft and water rich sand layer between Juyuanzhou Station and Hongwan Station of Fuzhou Metro Line 2, this paper expounds reinforcement of the shield receiving end, dewatering, control of the shield receiving attitude and secondary grouting, providing reference for shield tunneling in similar geological conditions in the future.