Abstract:In order to solve the hard technical difficulties of wellbore stability, boreholecleaning, lubricating & resistance reducing and reservoir protection for shallow horizontal well drilling in Ordos basin, by the analysis on the geological characteristics of the reservoir and based on the previous use of polymer drilling fluid, MC-VIS, ABSN, nanoemulsion and composite shielding temporary plugging agent were selectively added to develop a nanoemulsion plugging drilling fluid system. On the premise of safety drilling, the core permeability was restored up to 8350%. By the application in Qiping 1, it is showed that the nanoemulsion plugging drilling fluid system can satisfy drilling construction requirements of shallow extendedreach horizontal well in low permeability reservoir and provide technical support for efficient exploiting shallow reservoirs in Ordos.

Abstract:The paper introduces an improved retrievable eccentric wedge about its sidetracking method, technological measures and the efficiency. Compared with the traditional one, this eccentric wedge has the advantages of fast sidetracking, inclined coring, no accident threat, no influence on subsequent wire-line core drilling, no specific reaming process and reuse of the eccentric wedge, by which the technical difficulties of bit burning were solved with sidetracking for ZK901 in hard rocks.

Abstract:Located in south Tianhuan depression in Ordos Basin, HH12P103 horizontal well is an evaluation well belonging to China Petrochemical Group North China Branch. The drilled formation is complicated with salt layer in Huanhe; sticking is easy to occur in Anding and Zhiluo group due to collapse; there is coal bed in Yan'an group; and horizontal section is in clay intercalation where collapse is easy to occur. Leakage, collapse and deviation happened during the drilling process. According to these complicated geological situation and drilling difficulties, drill string assembly was optimized, combined application of single bent-housing motor and MWD was used for anti-deviation and centralizer was used in horizontal section. Process measures were adjusted as frequently as possible with small amount for each time to ensure the smooth well trajectory. Meanwhile, mud properties were optimized timely during the drilling operation, the three-level solids control equipment was used continually and the shale shaker with 150 screens was used to clear away the harmful solids in the mud timely to ensure the hole cleaning, drag and torque reducing to improve the ROP.

Abstract:The type and property of drilling fluids play an important role in improving core drilling efficiency in the polar ice and ensuring the stability of borehole. Based on the investigation of the working principles of armored electric machinery drilling tools and the cycle approach of drilling fluids, this paper made a detailed analysis on the relationship between the rising and falling speed of drilling tools and the viscosity and density of drilling fluids. Current types of drilling fluid and their existing problems were also discussed. The type and property of the drilling fluid available to the polar ice core drilling were determined based on the test data of the binary fatty acid glycol ester, low molecular weight saturated fatty acid ester and methyl silicone oil.

Abstract:The formation of Baoshan mining area in Dangping tungsten mine was complicated with hard and broken rocks in Jiangxi Province. Drilling was very difficult because borehole collapsing, diameter shrinkage, sticking and burying often occurred. According to the characteristics of complex formation and the construction difficulties, a set of pertinent technical measures were summarized in equipment selection, borehole structure, bits selection, washing fluid and wall protection & leakage control. Good effects have been obtained in the field application.

Abstract:Gansu Yangshan mining area geological structure is complicated, broken strata alteration strong, multi layer leakage, drilling leakage loss is a common phenomenon. On the basis of in-depth study of the mechanism of formation leakage, the polymer gel plugging technology is explored and tested. In the construction, polymer gel plugging is not limited by the leakage passage, which can enter the space of cracks and holes, and ultimately achieve the purpose of sealing leakage. In ZK2232 field application shows that the use of polymer gel plugging agent and other inert bridging agent can be used to solve the leakage of the drilling process, and the effect is better.

Abstract:Shale oil horizontal wells were arranged in Shengli oilfield, including Luojia and some other blocks for shale oil development. With shale bedding and micro fissure developing, the borehole instability is extremely easy to be caused in drilling process. At the same time, due to the long horizontal section, there are the difficulties of lubrication and borehole cleaning. For the construction difficulties and risks, the drilling fluid scheme for shale oil reservoir was worked out by research: amine-based and oil-based drilling fluid system being used for the second and the third sections respectively, and the drilling construction was successfully completed. The drilling fluid technology used for shale oil reservoir in Shengli oilfield is introduced in this paper and the discussion is made on some technical problems in the application.

Abstract:It is difficult to speed up drilling in deep and ultra-deep wells in Dagang oilfield mainly because of the poor drillability in conglomerate of Guantao formation and compact mudstone of Shahejie formation; abnormal high temperature and high pressure in deep oil and gas reservoir and the characteristics of high density and the high viscosity of the drilling fluid. To explore the matching technologies suitable for optimized and fast drilling of deep and ultra-deep wells in Dagang oilfield, the research was carried out based on the drilling case of Binshen 24-5-27. By the optimization of drilling fluid systems, application of drilling with fine pressure control and compound drilling with effective PDC bit screw motor, this project was completed with a drilled depth of 4510m, drilling cycle of 36 days and average penetration rate of 11.56m/h. The research shows that the effective drilling cycle is mainly profited from the improvement of ROP and ordered connection of production organization. Compared to the history index well of the same block, the ROP is increased by 15.27%, organizing time is shortened 31.68% in the second and the third sections, and the drilling cycle was shortened 18.78%. This matching drilling technology could provide the engineering technology support for effective exploration of deep oil and gas reservoir in Dagang oilfield.

Abstract:The related treatment methods of sticking are mainly by up-lifting and down-lowering drilling tool or rotating turntable with external force to make drilling tool to restore free state; by adjusting drilling fluid performance, putting condensed slurry plug, acid injection, grouting pipe freeing agent and reverse circulation to move or damage the infillings between the pipes and borehole wall; by the use of reverse thread drilling tools to fish and even by casing milling to pull out the stuck drill. A serious sticking accident occurred in the drifting process in DPT-305 well of Daniudi gas field, and the final stuck freeing was completed by heavy slurry cleaning fluid, acid injection, pipe freeing agent grouting and pressure holding in annular space; by fixing turntable and moving it up and down to apply torque to the stuck drill and by the use of reverse thread fisher. The causes of the accident are summarized and the analysis on the treatment process is made, which could be the reference experience for similar accidents in future.

Abstract:As its high construction efficiency in the bedrock, especially in the hard rock area, DTH drilling is the preferred technology. But in China, one-time reaming by DTH hammer with diameter of more than 660mm is not many, and one-time reaming and slag discharging by normal circulation cluster DTH hammer with diameter of 660mm is even fewer. The drilling test in Jinneng 2# gas drainage hole proves that reaming by use of 660mm cluster DTH hammer, one-time reaming and slag discharging with normal circulation can be realized, and there are also the advantages of rapid reaming, high drilling efficiency, short construction period and strong adaptability. The average drilling speed is 6.36m/h in hard rock formation and the highest is up to 9m/h, which is 10 times higher than normal circulation roller bit drilling. By this technology, the trapped personnel in mine disaster can be rescued in the shortest time, and drilling technical difficulties can be solved in water deficit area and serious loss zone.

Abstract:The fault gouge formation containing breccia was drilled in the south of Aikeng mining area of Qinghai Province, continuous drilling was almost impossible, because borehole collapsing, block falling and sticking often occurred. By the match usage of sodium silicate and related drilling fluid additives, sodium silicate potassium base inhibition flushing fluid was prepared to protect the hole wall by the formation pressure balance; and by increasing the outside diameters of diamond bit and reamer adjusting, borehole collapse, shrinkage, and sticking were solved.

Abstract:There is a large section of shale formation in Iraq Rumaila oilfield, spalling and caving-in happen easily. The sandstone reservoir is thick and permeable, which is prone to leakage and generating slim hole. In the reservoir with good permeability, leakage and slim hole are often met. From the simple pursuit of the downhole stability at the very beginning to that the borehole wall stability, reservoir protection and lower friction in S & J shape wells are then taken into account, today's no-solid KCl polymer drilling fluid system is formed. The paper describes the formation of this drilling fluid system and the application effect in the laboratory experiments and the field application in detail.

Abstract:Electro-hydraulic proportional control technology is used for XDQ-1200 light full hydraulic core drill with the advantages of high automation level, high efficiency, easy operation and high reliability. The paper briefly introduces the performance characteristics of the drill, expounds the power head rotation, hydraulic control principles of feed system and overall electric principle design. Production test shows that the drilling operation is well with advanced drill functions of stable work, fast drilling speed, simple operation and high degree of automation.

Abstract:As an important part of drilling rig, the main tower provides support, feeding guide rail and positioning in the feeding process, it must has sufficient bearing capacity, stiffness, strength, integral stability and necessary operation space. This paper introduces the mechanics analysis on aluminum alloy structure used for the main tower of XDQ-1200 light full hydraulic core drill.

Abstract:Spindle drilling rig, with mechanical transmission and hydraulic driving, is still a kind of main model widely used in China at present, hydraulic system is an important component of the whole rig. Aiming at the existing problems in the hydraulic system of deep hole spindle drilling rig, upgrading improvement was made and good effect was verified by practice. The main measures of optimization and upgrading of spindle rotary drilling rig and the practical application are introduced in this paper.

Abstract:The dill string vibration is inevitable during drilling process due to various causes. With in-depth research, it is recognized that the drill string vibration not only has negative influence on drilling operation, but also can be used to get a lot of underground information. Using a drill pipe model, the analysis was made on the vibration characteristics under different working conditions; multiple modes of transverse vibration, longitudinal vibration and torsional vibration were obtained, as well as the corresponding stress-strain diagram. The vibration modes were compared with the diagram and the consideration was also made on the drill string failure modes in order to find out the correlation between vibration and drill string failure to make vibration helpful in production.

Abstract:Matrix hardness is an important characteristic of diamond bit. It should be suitable for hardness (drillability) and abrasiveness of rock to be penetrated. Matrix hardness has direct influence on technical and economical indexes of drilling and choice of drilling parameters. Experimental research shows, that matrix hardness difference is big and not fairly well-distributed. The main reason of the big hardness difference may be low pressure (5 MPa) while sintering process of hot pressing. Diamond bit, drilling parameters and operation technology are all important. Probably low technical and economical results of diamond drilling are not connected with the bit, but with the drilling parameters and operation technology. Transition from drilling with experience to drilling with science is advocated.

Abstract:In the construction of Nanchanggou shallow large-span tunnel which passed through the road for the passenger dedicated line of Chengdu to Guiyang, various heavy vehicles posed threat to the tunnel construction and road traffic safety. FLAC3D was used for numerical stimulation of construction progress under the conditions of no traffic and with traffic load respectively to analyze the stress and deformation under the different working conditions. The results showed that the traffic load had little effect on the tunnel construction. The analysis on the tunnel passing process and the monitoring data show that the numerical stimulation of under-passing Nanchanggou tunnel is reasonable, which provides useful guidance for construction.

Abstract:The shallow layer of an office building site was reclaimed by backfilling, the thickness of filling layer was about 10m with particle size of 20~80cm. To meet the requirements of basement structure and pile foundation construction, generally the excavating depth was not less than 8.7m and the local depth reached 14.4m. It is particularly important to select proper foundation pit support plan for the very difficult support in this project. Step-slope excavating and water-sealing curtain scheme was chosen, the safety of the foundation pit and the surrounding buildings were ensured in the design calculation. The results show that this selected scheme is reasonable, safe and reliable.

Abstract:Imported from Sweden, Atlas-A32 down-the-hole drill was used in 4 ultra-deep inclined directional drainage holes with diameter of 130 mm and depth of 80m in the left bank abutment of Longyangxia hydropower station, drilling from abutment EL2610 to the theoretical design borehole bottom location EL2530 drainage gallery(2m×2.5m). According to the difficulties caused by drilling tool vertical deviation of 3% (vertical deviation of 3% is verified to be scientific). The technical bottleneck of too large vertical deviation in ultra-deep directional hole construction with down-the-hole drill were overcome on the control of technical parameters and technology. The paper summarizes technical achievements of ultra-deep inclined directional holes constructed with Atlas series down-the-hole rotary percussion drill from Sweden.