Abstract:The drill bit breaking rock would produce broadband vibration signal, different frequency represents different information. Due to the lower energy and higher attenuation, the high frequency signal is difficult to be detected. In this paper, the low frequency signal characteristics in the bit breaking rock are studied. By the analysis on micro-drill experiment data of different rocks, it is shown that the signals produced by bit breaking different rocks have fixed frequency characteristics in low frequency.

Abstract:Karst fractured formations are largly distributed in south of China, in which serious leakage, block falling and other difficulties are often occurred in drilling construction. With the construction cases in Weng’an of Guizhou, the analysis is made on the characteristics of karst formation， the applicability of micro-foam mud technology in karst fractured formation is put forward with some items that should be paying attention.

Abstract:China has large population with insufficient water and land and varied geomorphology, shale gas reservoir has the characteristics of deep burial, high dimension, low permeability and poor alterability. The application of horizontal well and multi-interval fracturing techniques have certain limitations in China, which are conventional techniques for shale gas development in America. For this reason, a new type of development well is proposed. Being different to traditional vertical, deviated or horizontal wells, it is formed with the main shaft and the surrounding auxiliary caves. The main shaft is designed for production, the auxiliary caves are for reservoir stimulation. The completion methods of main shaft can be vertical well or deviated well, the auxiliary caves are branch directional well or cluster wells and may be the combination of the two. For the reservoir stimulation, the cost-effective cumulative blasting technology is adopted in place of the high-cost of hydraulic fracturing; taking multi-cave in place of multi-stage fracturing and simultaneous fracturing in order to keep the continuity and effectiveness of reservoir fracture system, expand the effective drainage area and reduce the spacing density. To simulate the effect of reconstruction, an experiment was carried out on the hard concrete pavement, the result shows that by a number of caves and vibration, interconnected fissures can be produced to achieve the overall improvement of reservoir permeability.

Abstract:As an unconventional energy, shale gas is widely distributed with abundant reserves. However, because of the low porosity and low permeability in reservoir, shale gas has not been large-scale extracted. Until the past 20 years, shale gas mining technology is developing rapidly, which is mainly due to the progress of hydraulic fracturing technology. Fracturing fluid is an important part of the hydraulic fracture treatment and its performance directly affects the success of hydraulic fracturing. Based on the investigation of domestic and abroad literatures, combining with the developing course of fracturing fluid technology in China, the advantages, adaptability and existing problems of several commonly used fracturing fluids in shale gas exploitation are analyzed, and 2 new anhydrous fracturing technologies are summarized. Combined with the particularity of the shale gas reservoir and fracturing technology development status in China, suggestions suitable for China's shale gas fracturing fluid technology development are put forward and the importance of paying attention to environmental protection in the preliminary stage of shale gas is emphasized.

Abstract:There are the characteristics of dense lithology, strong abrasive and poor drillability in upper formaton in Jiaoshiba area of Chongqing, active shallow gas with sulfur in Changxin formation and long third spud horizontal section, high friction and being easy to collapse in clay shale. The prominent problems were low ROP, difficult well control and long drilling cycle. According to the above difficulties in gas reservoir drilling, the analysis was made mainly on the drilling technology, wellbore stability maintenance and drilling fluid; optimization of drilling tool structure, optimizing bit selection, inhibition of wellbore instability were carried out in order to speed up the drilling speed in Jiaoshiba area. “Screw drill high efficient PDC bit” with high-quality drilling fluid were applied in 4 wells of the 12th drilling platform and the drilling cycle was greatly shortened. The construction of Jiaoye 12-4HF sets the record of the longest horizontal section in unconventional shale gas horizontal well for Sinopec Group, and drilling speed is effectively improved.

Abstract:By testing TP131H well, it is known that the target layer is water layer. The five-section sidetracking horizontal well TP131HCH was designed based on the analysis on seismic data in order to improve the producing degree of reserves around the well and reduce drilling cost by making full use of the old well in vertical well section. Due to the steady inclined section, the horizontal displacement of wellbore trajectory is effectively extended by five-section horizontal well, which meets the requirements of geological water avoidance. According to the difficulties caused by ultra depth and high temperature of openhole sidetracking horizontal well TP131HCH, the paper introduces the relevant methods such as optimization design of borehole trajectory, sidetracking, well track control and drilling fluid in drilling process.

Abstract:In order to speed up the development of horizontal well drilling in Redebye oilfield, by the study on rock mechanical properties, rock physical and chemical properties, wellbore trajectory, BHA and bit selection, a science is formed of mainly by PDC bit combined drilling, well trajectory control, plugging drilling fluid and two-stage cementing at screen top technologies, and a rational matching processing technology is also developed. These are applied in the field construction to speed up the horizontal well drilling in Redebye and save the development cost. In 2012, the average cycle of horizontal well drilling was 42.96 days and well completion period 53.38 days; in 2013, those were 19.58 days and 37 days, being shortened by 54.4% and 41.1% respectively.

Abstract:Based on the study on the characteristics of CK1 geothermal well in Guizhou and the construction process, the requirements and improvement are put forward in drilling and completion processes of geothermal well. The summarization and the analysis are made on the actual situation of geothermal resources exploitation by present geological exploration units, the existing problems and solutions are found, which provide the experience for geothermal field exploitation.

Abstract:The strata are brittle, hard and fragile in Xiarihamu mining area, which has certain representativeness in Qimantage key metallogenic belt of Qinghai. Many problems such as short bit life, low drilling efficiency and hole accidents often occur in the drilling process. According to the strata characteristics and drilling difficulties and based on the summary of drilling experience, analysis is made on bit and parameter selection, drilling rig selection and efficiency analysis, drilling tool vibration and dispose, hole wall protection and plugging and hole structure design and construction, comprehensive technical measures are also put forward.

Abstract:The paper briefly introduces the lithology and structure construction in Chentaigou iron mine, induces 3 aspects of difficultis of collapse, block falling, water leakage, water inflow and diameter shrinkage affected by bad geological conditions; hole bending caused by strongly deflecting formation of thick phyllite and slipping formation encountered in deep drilling. The measures and methods are put forward to these 3 problems with good effects.

Abstract:In high gas coal measure and ultra thick water sensitive formation with water gushing in different formations, rational design of borehole structure, selection of equipments, drilling methods, drilling parameters and correct operation are the premise of successful completion of drilling operation. And the correct use of slurry is the key for prevention of hole accidents. By proper application of high density water-based film forming mud, the pressure balance between liquid column and the hole wall can be kept and hydration expansion and dispersion breaking off can also be inhibited by fluid loss control in water sensitive formation to prevent the collapse of hole wall and realize the stabilization. The paper introduces the application of these technical measures in complex formation of high gas ultra thick coal measure with water gushing of Yangzhai coal mine in Guizhou and the application effects.

Abstract:Differential pressure sticking is a kind of downhole accidents frequently encountered during drilling, which can cause enormous economic loss if it not being disposed in time. In this paper, by the analysis on causes of differential pressure sticking and its characteristics and combined with the engineering cases, the methods of disposing differential pressure sticking using the booster in bedrock stratum are presented as well as the operation rules and points for attention.

Abstract:The existing evaluation method of flushing fluid has some problems in evaluating the oil-base drilling fluid. This paper presents a new indoor evaluation method which would be suitable for evaluating both oil-based and water-based drilling fluids by using the principle of equal shear rate between annular wall and inner cylinder wall of improved device. Many indoor simulation experiments have demonstrated that this method can reflect flushing efficiency better; and by this method, the simulation evaluation can be made on influence of flushing efficiency to cementing conditions in the first or second bonding interface. This method has the advantage of convenient operation and is suitable for both water-based and oil-based drilling fluid cementing conditions.

Abstract:High angle directional well can run through many oil reservoirs and increase oil and gas leakage area to improve the production of single well. Through the analysis on the difficulties in well Pu182-Xie154 construction, the casing program and the trajectory profile are optimized before the construction. Rational BHA and drilling parameters are selected together with the safety drilling technical measures of hole cleaning technology, friction resistance and torque reducing technologies and wellbore stability technology, which ensure the smooth construction of this high angle directional well.

Abstract:Difficulties of large height difference of construction surface, small working site and complicated formations of dangerous rock exist in Suofengying hydropower station of Wujiang project with several fracture zones distributing in the mountain, the borehole must be drilled through fractures. The paper introduces the special construction technology used in upper anchor cable construction for Dr2 dangerous rocks in Suofengying hydropower station, where it has 110～134.5m height difference to the lowest platform.

Abstract:In the brazing-sintering process of the exploration diamond bit, the dimensions of the core mould, outer mould and the steel body directly determine that of the diamond bit and have a great influence on the use performance of diamond bit, while the study on the mould dimension design is not comprehensive in the existing literature. By the detailed research on heating and cooling process in the bit brazing-sintering, a set of more intuitive calculation formulae of mould dimension design and the methods to prevent mould from expanding crack are built up.

Abstract:The optimization study on parameters of a large diameter drill pipe joint thread used in mine shaft rising boring is conducted through combining the orthogonal experiment with the finite element theory in this paper. The study results show that small end outer diameter of the screw thread, the taper, side angle of the thread and length of the screw thread etc. have a significant impact on the strength of the thread, the significance order of these parameters on the thread strength and the optimal value of the thread without considering the interaction of these parameters are obtained.

Abstract:Conventionally, the influence of guy wire and wind load on derrick was often ignored in the static strength analysis on derrick of truck-mounted workover rig, but it does not accord with the actual working conditions. This paper made the finite element analysis on a derrick of truck-mounted workover rig through ABAQUS software. Under different static hock loads and wind loads, the maximum static hock load the derrick can bear was obtained and the weak point position on derrick was determined. Based on the calculation, the cable-stayed range of guy wire was reasonably shortened.

Abstract:By setting surface subsidence monitoring instruments in a large area of the loading site, the on-site monitoring lasted 3 years, and the analysis was made on the deformation characteristics of coastal hydraulic fills soft ground subsidence under large area heaped load. It is revealed that the deformation characteristics of soft ground under large heaped load are different from those under normal load and the soft ground deformation settlement law of large area heaped load conditions is summarized. By the use of numerical methods, the foundation deformation law is simulated and the foundation failure mode is analyzed, the numerical calculation results and the field monitoring results have a good coherence. Under 400kPa heaped load force, the maximum settlement value is approximately 1.6m.

Abstract:According to the test results of expanding pressure of large borehole static cracking，the reaction mechanism of large borehole static cracking agent is analysed. Based on momentum balance principle, a new sealing device was invented and has been successfully applied to analogue cutting engineering practice. The hole-spacing approximate calculation formula is modified with test data of cutting practice. The technology has some reference to cutting engineering practice in conditions of small interval intersection.