Abstract:Achieving green exploration is a challenge that all geological exploration units must face and also a mustdo for them. Shandong Gold Geology and Mineral Exploration Co. Ltd. is the first unit to explore and practice the way of green exploration in Shandong Province. First, the green exploration plan, system and standard of the company were made up. Then, in the preferred demonstration project for green exploration, standardized management was implemented for the drill rig with the optimal design of “multiholes at one position ” to minimize land occupation; the XY6B drill rig was improved for energy conservation; technical upgrading was performed for the material, structure and layout of the drilling fluid circulation system to strengthen waste management with the environmental geotextiles laid, and the sound proof walls constructed to prevent environmental pollution. The experiences accumulated are worthy of promotion and reference.

Abstract:Well CGSD01 is a hydrothermal geothermal resource survey well organized and implemented by China Geological Survey. The well was completed at the depth of 405168m with diameter of 216mm. During the drilling process, problems such as insufficient safety factor for largediameter casing running, formation leakage, low core recovery in complex formation were encountered. This paper introduces the well structure as well as drilling and completion technology for the well. The complex problems in the drilling process were solved by taking some measures such as buoyancyaided casing setting, multiprocess leak plugging, improvement of the coring process in complex strata. The drilling technology and completion recommendations for the deep geothermal drilling in this area are summarized.

Abstract:The CGSD01 well, as a 4000m deep geothermal survey well deployed by CGS , is of great significance to the evaluation of deep geothermal resources in Dongli Lake District, Tianjin. The quality requirement on the well completion is high. The Institute of Exploration Techniques, CAGA, while testing of the drill rig XD40 developed under the research program “4000m Geological Core Drilling Technology and Equipment”, innovatively set the first tier casing of 3397mm to1467m by use of the buoyancyassisted casing setting process with the less hook load of the drill rig, laying a good foundation for upcoming drilling operations. This paper introduces the theoretical analysis and practical application of setting casing with buoyancy.

Abstract:The Jiangdong Block of the Fuling Shale Gas Field is featured of complex geological structures and large dip angles. Problems such as low mechanical drilling rate, severe drag force and difficult horizontal trajectory control are encountered, which brings drilling problems to the fast drilling operations in this area. By summarizing the field operations and technical problem solving practices, this paper presents a set of fast drilling techniques through analysis of drilling processes, new tools, bit selection and speedincreasing tools suitable for the complicated geological conditions of Jiangdong Block. Comparison of the fast drilling technology with the conventional drilling method at the Jiangdong Block of the Fuling Shale Gas Field shows that the drilling duratiom in Jiangdong Block has been shortened from 235 days to 9033 days in the early stage of development. While the drilling rate and the reservoir intersection rate have been continuously improved, the working conditions such as drag forces, premature bit failures have been gradually reduced. Over three years of development, the fast drilling technology at Jiangdong Block of Fuling Gas Field has gradually matured, and the results have been applied significantly.

Abstract:In view of the complicated and serious leakage and collapse in the highrisk drilling zone in the Jin58 well field in 2017 and the difficulties in the following treatment of oil and gas fields where open holes were completed with preset 4in casing strings in the early period, and with the inhouse research, the survey of tight gas drilling and completion technology status at home and abroad, and the analysis of previous drilling experiences, it is concluded that: (1)there is a narrow negative safety density window at the Jin58 area; therefore the effective method for economic acceleration of ROP is to change the well structure for separate treatment of leakage and collapse under the existing technical and equipment condition; (2)the well is completed with 5in liner hanging down hole without cementing for comprehensive gas field management, reservoir protection and effective release of horizontal well productivity. According to the above conclusions and the actual condition of the environmental monitoring well, the suitable structure and completion method for the Jin58 area are proposed together with the optimal fast drilling and completion plan, which will be of some significance to rapid production in this area.

Abstract:Adjustment wells are mainly used for improvement of the well pattern through regrouping, and for fine production through subdivision of the payzone at the late development stage of the old oil fields so as to achieve stable or higher productivity. With the existing injectionproduction system and production status, the cement quality of the adjustment wells cannot ensure effective sealing between layers due to the complex formation pressure system and diverse formation fluid compositions. Based on the analysis of various technical difficulties faced by adjustment well cementation and their effects on cementing quality, this paper summarizes the existing problems with the cementing quality and the main technical measures to improve it at present, and put forward the technical measures and research directions to be taken in the next step, which lay a technical foundation for improving the cementing quality of adjustment wells.

Abstract:Sand entry and well clogging in the groundwater heat pump system often affect the operation and efficiency of the system. Taking a project in Jingzhou City as an example, analysis is made of selection of the water well drilling method in gravel with fine sand aquifer occurring widely in Jianghan Plain and the problems with pack material and the screen design. It is pointed out that one of the effective means to prevent sand entry from the fine sand layer is to wrap the stainless steel wire mesh around the screen pipe at present; anyhow it’s better to be used in conjunction with the reverse circulation drilling method, and the pack material should be selected according to the gradation curve of the aquifer to avoid the transfer of the filtration pressure to the screen pipe, thus reducing well clogging.

Abstract:Well Wanhandi1 was a geological survey well deployed and implemented in the Chaohu anticline tectonic belt in the middle section of the inrush nappe zone. The purpose was to obtain various geological parameters of OdovicSilurian shale in the Chaohu-Hanshan-Wuwei region， providing geological basis for the evaluation of shale gas resource potential and the optimization of favorable blocks in this region. This paper mainly expounds the general situation of the well site area, drilling techniques and process for Well Wanhandi1, drilling quality control, proper adaption of the drilling parameters during drilling, and effectively control of the borehole inclination, which conforms to the purpose of geological design. Analysis of the rig efficiency is made so as to provide experience for upcoming drilling.

Abstract:The ore bodies of Jinping Chang’an Gold Mine exist in sandstone in the form of sulphide deposits, which has the characteristics of deep burial, steep dip and difficult exploration. In the design of exploration boreholes in the mining area, the azimuth ranges from 70° to 250°, the inclination from 30° to 75°, and the borehole depth from about 100m to 800m. In view of the complex situation of hard, broken and leaking formation, and with the large designed inclination and strict requirement on hole deviation in this mining area, a new type of drilling equipment (XDJ4 full hydraulic core drilling rig) was adopted for drilling with flushing fluid of low viscosity, low specific gravity and good lubricity for borehole wall protection. Control and correction of borehole deviation were carried out by taking measures such as control of drilling rig installation, deceleration method, small diameter pilot drilling followed with correction of deviation by increase of WOB. As a result, the construction difficulties such as easy deviation and leakage were effectively solved, and the project was completed with high quality and full quantity as well as on schedule, achieving good economic and social benefits. This paper summarizes some experience and existing problems in the construction of large inclination boreholes in this mining area, which provides good reference for the construction of similar projects.

Abstract:The drill string is the core and key technology in deep land and deep water drilling for deep earth exploration; however, with the limited allowable drilling depth, the drill string of a single specification is difficult to meet the design requirements of 10000m extra deep continental scientific drilling and deep ocean drilling. In this paper, by reducing the weight of the lower portion of the drill string and improving the strength of the upper portion, the design of the drill string assembly is optimized. With the priority of tensile strength calculation, the demand on the drill string strength is satisfied in consideration of the safety factor and tensile allowance in case of dynamic loads and other complex situations, and the software for the drill string assembly design and safety coefficient calculation is developed, which can realize the drill string assembly design and safety coefficient calculation for different hole depths and drill rod structures.

Abstract:Proper foundation pit dewatering will have an important impact on the foundation pit excavation and the surrounding environment, so it is necessary to evaluate the foundation pit dewatering plan. In view of the problem of foundation pit dewatering at Yangzhong Jinyuan Times Shopping Center, MIDAS/GTS was utilized to study the effect of foundation pit dewatering. Firstly, according to the soil permeability coefficient provided in the geological survey report, in combination with the single well and double well pumping test results, the soil permeability coefficient and boundary functions required in the MIDAS/GTS were inverted. Then, with the parameters obtained from the inversion, a 3D analytical model of the foundation pit dewatering effect was established with consideration of the recharge effect of the backfilling well for simulation of the relationship between the water level drawdown and the time in the foundation pit any analysis and evaluation of the foundation pit dewatering effect, providing guide for earthwork excavation.

Abstract:In the test of deformation characteristics of soft clay soil in Shanghai, the test of deformation and strength of undisturbed soil under different stress paths is rarely carried out in engineering investigation, which makes the parameters provided in the investigation report not well consistent with the actual soil stratum in the excavation and unloading process of foundation pit. In this paper, taking a deep foundation pit project in Xujiahui, Shanghai for example, K0 stress path triaxial test was performed in the investigation stage. The test included loading, unloading and then reloading of the selected representative soil samples, and recording the stress and strain as well as modulus of deformation at every stage. The analysis of the test results shows that the stress path had an obvious effect on the soft clay soil, and the K0 stress path can reflect the deformation characteristics of the soil in the process of foundation pit excavation in the natural state. It is suggested to strengthen the promotion and application of the K0 stress path in the deep and large foundation pit projects which are sensitive to deformation.

Abstract:Take the deep foundation pit project of Jinan Gold International Plaza as an example, in view of the characteristics of soil rock combination formation, the support design with suspended piles and anchor cables in the layout of two piles plus one anchor was adopted. The design of the foundation pit, test of anchor cables and monitoring of the foundation pit are introduced. The acceptance test of anchor cables was carried out on site, and the test results meet the design requirements. The monitoring results show that the deformation of the supporting structure of the foundation pit and the settlement of the surrounding buildings are all in a safe state, which is far less than the alarm value, indicating that the application of the suspended piles and anchor support in the deep foundation pit in the soil rock composite stratum is very good with less costs and short construction period. The relevant design methods, experiments and monitoring results can provide reference for similar projects.

Abstract:In geological drilling and petroleum drilling, the bit is a very important drilling tool. Its technical characteristics, particularly its hardness and wearresistance, is related directly to drilling technical and economical index, i.e. penetration rate, bit footage and drilling cost per meter. In order to improve performance of the bit, South Russian State Technical University has proposed and tested cryogenic nitrogen and magnetization integrative treatment method for the bit. The hardness of the bit body, base of PDC and the solder layer were improved by 30%, 3% and 22% respectively. The field testing results show that the penetration rates of the bit with the treatment of cryogenic nitrogen and magnetization were improved than those of the normal one in each test, and the penetration rate of this type bit increased by overall 222%, achieving good results. Meanwhile, the obtained results were analyzed with Xray diffraction and electronic microscopic technology.

Abstract:The burial depth and complex formation lithology of poor cemented sandy gravel reservoirs make the drilling operation face some difficulties, such as low ROP, reduced footage. The paper studies the technologies of bit optimization and improvement of tool selection to overcome these problems, which achieved good results in drilling at Li567 Block of Shengli Oilfield, in particular with extended service life of the bits. This will provide effective technical reference for the subsequent development of similar blocks.