Abstract:Alaska North Slope(ANS) permafrost zone is rich in hydrate resource, where is one of the specified targets for hydrate R&D in USA. The PCB and PCS pressure core samplers for NGH in USA have been respectively developed and applied in DSDP、 ODP、 IODP and ANS since 1970’s. Hot Ice #1 well, the first dedicated hydrate research well in Alaska, was completed in early 2004. Newly developed Arctic Drilling Platform, Mobile Core Lab, Smart Drilling etc. were successful deploied in the research well despite of missing the hydrate layer. Mt. Elbert #1 research well was smoothly drilled(to 914m), cored(recovery 85%), logged and downhole pressure tested with MDS in February 2007. This science program successfully achieved all of its objectives. Naturally occurring geohazards and “Industrial” gas hydraterelated geohazards were studied, the latter can be categorized mainly as follows: Drilling through GH, Producing through GH and Producing from GHgeohazards. The theoretical and lab studied of NGH , especially for hydrate production with CO2-CH4 exchange technology, have been effectively executed for decades by many academic centers and universities in USA. In May, 2012, ConocoPhillips, in a cooperative effort with the JOGMEC and the U.S. DOE, successfully completed Ignik Sikumi #1 well gas hydrate production test using CO2-CH4 exchange method in ANS. Overall, the well produced for 30 days during the 38-day flowback period, with cumulative gas production approaching one million scf (28317m3). The test result shows that CO2-CH4 exchange for NGH production is one of the most important and effective methods, which can greatly mitigate environmental pollution and damage.

Abstract:With the continuous improvement and development of groundwater monitoring technology, the techniques, which use single-hole to monitor multi-level, supply in groundwater monitoring aspect widely. As a member of multi-level monitoring techniques, the continuous multi-channel monitoring well uses a new structure type of well completion to achieve monitoring multi-layer groundwater in single well, and collecting water samples for analysis of water quality. It can reduce the cost of construction and monitoring, improve monitoring efficiency. The issue described the completion materials and the improved well completion technology of continuous multi-channel monitoring technique in detail. Combining with application of the technique in Hei River basin groundwater monitoring processes and hydro-geological analysis of the actual monitoring data can verify the practicability and validity of continuous multi-channel monitoring technique.

Abstract:The real-time hydraulics model is one of the most important methods for modern drilling engineering to predict downhole conditions. This paper analyzes the influencing factors of real-time hydraulics model and a set of wellbore real-time hydraulic calculation and analysis model is established. The model takes into account the effect of drill string rotation on the velocity distribution. The model includes the wellbore annular pressure and equivalent circulating density. At the same time, by using the established hydraulic calculation and analysis model, the calculation results are more close to the actual underground situation according to the parameter changes along with the different temperatures and working conditions, which makes this model more practical.

Abstract:Qiangtang basin is recognized as advantageous prospecting area for natural gas hydrate and core drilling is the most direct and accurate method to identify natural gas hydrate. The technical methods of large diameter coring and core protection by low temperature mud were assigned to meet the requirements of natural gas hydrate drilling; trial production of simultaneous casing coring tool and large diameter wire-line coring tool were carried out; low temperature mud formula was gradually improved and new type efficient mud cooling device was developed. In the construction process of natural gas hydrate survey well in Yahu area, in spite of complex formations and bad environment, sample drilling construction was completed at final depth of 700.70m. The core samples can satisfy the geological requirements, the stratum lithology, thickness of frozen earth, gas source and physical properties of rock are found out, which provides geological data, technical support and talent reserve not only for the evaluation of natural gas hydrate resources but also for other oil and gas resources investigation.

Abstract:Drilling and fracturing come to high cost for vertical well in coalbed methane development with small control area and low production rate of single well; while for horizontal wells in coal seam, drilling is difficult with high risk and wellbore trajectory control is difficult in thin coal seam, the harmful solid in drilling fluid has serious reservoir damage and the recovery factor is low. Based on the above, this paper analyzes the geological structure of coal measures in Zhijin block of Guizhou and puts forward a new way that horizontal wells are laid in stable non-reservoir of coal measure strata to get through the coal seams above and under the horizontal wells by hydraulic fracturing for multi coal seams development at the same time. Compared with the conventional development mode, the horizontal wells in non-reservoir have the advantages of small drilling risk, light reservoir damage and high production of single well; and at the same time, coal measure tight gas and shale gas can be developed to improve utilization ratio of unconventional gas. The research on the development technology of Guizhou Zhijin coalbed methane in non-reservoir with horizontal wells provides new way to solve the difficult development of coalbed methane in Guizhou coal measures strata with the characteristics of many thin coal seams and small interlayer spaces as well as the utilization of coal measures gas.

Abstract:Well leakage brings not only losses to drilling engineering, but also great difficulties to the exploration development of oil gas resources. Permian igneous rock developed in the northern part of Shunbei area with formation fractures, leakage in drilling process is the main complex downhole situation. At present, Permian leakage happens frequently, which causes collapsing and block falling and has adverse effects on construction progress. To solve this problem, the research on plugging while drilling technology for Permian in Shunbei area is carried out. Combined with the drilling practice of wells SHB 1-1, SHB 1-5 and SHB 1-6 and considering Permian strata characteristics, this paper analyzes the drilling difficulties of Permian in this block and summarizes the concrete construction methods of plugging while drilling technology. In order to cope with the possible large leakage, plugging formulas are optimized for the boards with seams of 1, 3 and 5mm respectively.

Abstract:Based on the introduction of drilled strata characteristics of Zhuxi mining area, the construction difficulties are analyzed systematically in the aspects of deep drilling depth and easily being inclined, more complex formation comparing with shallow drilling, higher requirements of drilling quality, especially for hole inclining and some others. This paper summarizes the main drilling equipments selection, drilling construction management works and major technologies including drilling methods, hole structures, drill bit selection, drilling technical parameters, flushing fluid selection and hole wall protection and plugging measures; suggests improving construction capability of drilling equipments, curbing serious downhole accidents in future deep hole construction, insisting on the control principle of prevention first and treatment secondary and being prepared for hole wall protection with mud.

Abstract:Increasing the length of coal-bearing interval of through beds hole in soft coal seam coal can improve gas drainage effect of single hole, which can be realized by using the flexible drilling assembly. This paper presents the mechanical model of flexible drilling tools construction, makes the studies on the kinematics characteristics of strong deflection and puts forward the kinematics curve. According to the above, the strong deflecting drilling technology is researched to increase drilling rate in coal seam as far as possible.

Abstract:Well GL-1 was completed at the depth of 6300.83m. With the expected bottom temperature up to 260℃, the drilling fluid with 260℃ high temperature tolerance was used in the 6 months construction. The application shows that this drilling fluid has advantages of good temperature tolerance (260℃), strong anti-pollution ability, good lubricity with light damages to oil and gas reservoirs, is conducive to hole wall stability. The successful construction of this well provides safe and effective technical guarantee for the further exploration and development with high temperature in deep layer of Daqing oilfield.

Abstract:Diamond drilling is a main method in geological exploration, the drilling equipment, drill bit, drilling technology, drilling operation and production management are important in diamond drilling production and the technical and economic indexes of the drilling are more closely related to the service performance of drill bits, so all of these have become a concern. Russian doctor of technical sciences Kubasov V.V. and others have made a lot of studies in improving diamond bit matrix service performance and achieved good technical and economic effects. This paper introduces the research contents and achievements in selective crushing of low grade diamond, thermal treatment of diamonds, cryogenic treatment of diamond bit, control technology of matrix performance and so on.

Abstract:Foundation pit dewatering is the key to the whole foundation pit safety. Although the waterproof curtain was built in the foundation pit excavation of Nanshanhu complex building in Nantong, it is still necessary to make a safety assessment on the dewatering scheme of the foundation pit. 3-dimensional seepage model is established by using the MIDAS/GTS numerical analysis software, by the simulating analyzing a single well pumping test in the field and synthesizing the permeability coefficients of indoor tests in the geological exploration report and pumping tests, the seepage boundary function and the permeability coefficients fitted for the practical engineering situation are inversely deduced; then the 3-dimensional seepage model is established by using the parameters reversely derived to simulate the changing relation between water level and time in multi wells pumping. The dewatering effect of multi wells is analyzed to verify whether the dewatering design is reasonable in order to guide the foundation pit excavation.

Abstract:According to the characteristics of ice layer drilling, from the point of view of drilling hydraulics, the effect of quality and length of drilling tool, the viscosity and density of drilling fluid and some other factors on the characteristics of drilling tool lowering speed are analyzed and tested. Through the tests on the lowering process of drilling tools, with 4 different lengths and different qualities, in 2 kinds of esters drilling fluid, it is concluded that the lowering speed of the drilling tools is inversely proportional to the length of the drilling tool, and is proportional to the quality of the drilling tool, and the lowering speed of the drilling tool decreased with the increase of the viscosity and density of the drilling fluid. The acceleration time of the drilling tool lowering is mainly related to the viscosity and density of the drilling fluid, as well as the shear rate of drilling fluid while flowing on the surface of the drilling tool.

Abstract:Through the analysis on the construction conditions, the drill pipe breaking accidents and the broken parts in the geographical survey well in Tonghua Basin, and on the basis of drill pipes and drilling parameters, the thread stress of the drill pipe joint was calculated. The modeled thread connection part of drill pipes was established by means of SolidWorks, which was then introduced into Ansys Workbench for stress and fatigue simulation analysis to predict the fatigue life of the drill pipe joint. Based on the analysis on simulation results and combined with the geological core cataloging and logging data, the causes of the drill pipe breakage occurring under the conditions of gushing water with a large amount of gas are discussed and the drilling parameters are optimized to reduce the occurrence of the drill pipe breakage in the hole.

Abstract:As classic drilling fluid rheological properties test instrument, Fann 50SL HTHP (high temperature and high pressure) rheometer has played a great role in the research and development of high temperature drilling fluid system. But the fluid is prone to climb upward when the original Fann 50SL HTHP rheometer is used to test rheological properties of high viscosity fluid, which will result in inaccurate test data and poor reproducibility of experiment, and even polluted bearing lead to serious problems of bearing rust and driving motor burning. Through the analysis on the flow characteristics of the high viscosity fluid and the measuring principle of Fann 50SL, the reasons influencing the accuracy of test data are found out, on this basis, 2 kinds of prevent-climbing structures are designed and installed on Fann 50SL HTHP rheometer, the climbing upward is effectively solved.

Abstract:This paper introduces the structure and characteristics of the power head, a major component of deep sea core sampler. According to the special conditions of deep sea drilling, a self-desertion mechanism and impact break-out mechanism are specially designed on the power head to abandon the sticking drill pipes in hole when they can not be withdrawn or to loose the drill pipe threads by compact when the power head torque hydraulic motor fails to unscrew drill pipe. This paper emphatically introduces the structures and working principles of drill pipe self-desertion mechanism and impact break-out mechanism.

Abstract:Small diameter core drilling offshore construction must rely on offshore drilling platform as the construction site. Due of the larger influence of wind, waves and other natural factors in the construction environment, the transportation, construction process, personnel safety and some other aspects are quite different with the land construction. In order to ensure the offshore core drilling safety, by the comparative analysis on the similarities and differences between dangerous sources at sea and land construction and through 3 steps of hazard identification, assessment and control, the systematic management of offshore construction risk control is carried on in platform construction and demolition, construction process, maritime traffic and personal protection and other aspects in technology and management for safe construction.