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Abstract:The public benefit onshore oil and gas survey is to carry on basic， public and strategic exploration focused on new areas， new strata， new types and new fields. In recent years， many important geological discoveries and shale oil & gas survey breakthroughs have been made through a number of scientific and technological projects in oil and gas geological survey， making contributions to national energy security. However， the geological survey work on “new areas， new strata， new types and new fields” has the characteristics of many complex structural areas， low degree of work， few engineering practices and relative lack of data， which lead to the challenges of poor prediction of complex problems， high safety risk and difficult realization of geological objectives. With respect to the practice of oil and gas survey and drilling practice in recent years， this paper expounds the overall status， difficulties and challenges， and advances in the public benefit onshore oil and gas survey drilling engineering. From the perspectives of safety and environmental protection， obtaining full and exact geological data， increasing speed and reducing cost， some research suggestions are put forward to solve technical problems so as to promote the development and progress of the public benefit onshore oil and gas survey drilling engineering.

Abstract:To seek breakthroughs and discoveries in shale gas resource exploration in the lower reach of the Yangtze River， China Geological Survey deployed 25 shale gas wells in Aahui province from 2015-2021. In view of malignant leakage， difficult coring， difficult drilling and well wall instability due to complex geological conditions in the exploration area， including complex geological formations， soft and hard interbedding， fault development and broken formation， a shale gas drilling technology system has been developed for the lower reaches of the Yangtze River （Anhui） through the selection of multiple types of drill bits， optimization of drilling tool combinations， drilling fluid configuration and drilling techniques， The technology system includes high-efficiency and high-quality coring technology for the fracture zone， research on soft and hard interbedding deviation correction and control BHA， optimization of bits in strong abrasive hard formations， treatment methods for malignant leakage and sticking， drilling fluid plugging technology for horizontal well sections， and wellbore stability treatment in water sensitive formations. The research may provide beneficial reference for optimal well drilling design and drilling operations for shale gas survey.

Abstract:Well WND1， a Lower Yangtze shale gas geological survey well， was drilled into a karst cave in Ordovician Baota Formation limestone strata . It can be diagnosed that a semi-filled cave with axial length of 2.8m along the borehole has been encountered by analyzing the cave identification features and law， such as drilling string fall-down， lost return of mud， drilling-time as low as 0 or extremely low， core missing， significant decrease in resistivity， obvious decrease in density， increase in acoustic and neutron values. Based on the above diagnosis and in view of with the actual working conditions， comparison of the characteristics and application range of common treatment methods for karst cave， such as bridge plugging， cement plugging， drilling with lost circulation and sealing off with casing， bellow pipe plugging， gel plugging， well location relocation， was conducted with forced drilling with fresh water and sealing off with casing selected to drill to the intact formation and then casing set for sealing， which ensured the smooth completion of Well WND1 and the realization of drilling objectives.

Abstract:Well Wanwangdi-2 is a shale oil and gas geological survey well located in the Xuling sub-sag slope zone of Wangjiang Sag along the fold fault zone of the Lower Yangtze block with the design depth of 1600m and the completion depth 1632m. The purpose of drilling is to explore the gas-bearing properties of the shale in the Permian Dalong formation-Gufeng formation； and the regional stratigraphic sequence， the lithology， and the lithofacies development to obtain geological parameters. This paper introduces the drilling work of Well Wanwangdi-2， and describes the main drilling technology and technical measures. In view of the difficulties of mud-sand interbedding， unstable well walls， complex lithology and low core recovery rate， the wire-line coring tool and technology was improved with the drilling fluid system modified for sensitive formation and the drilling parameters optimized to increase drilling efficiency and ensure core recovery rate. The problems in the drilling process are also analyzed with improvement measures proposed to provide technical reference for drilling of similar small-diameter shale gas survey wells.

Abstract:In order to find out the stratigraphic sequence and geological parameters in the shale gas exploration area in western Hubei and reveal the characteristics of stratigraphic oil and gas potential， China Geological Survey has deployed a large-diameter shale gas geological survey Well Ejandi-4 in Jianshi， Hubei province， with a drilling depth of 2026 m. In view of drilling challenges， such cementing difficulties， e.g. gravel layer， confined water layer and dipped formation， collapse and falling stones， with proper selection of the drilling bit， optimization of the drilling string， and development of the high-efficiency drilling fluid system， a drilling process combining quick drilling and deviation prevention for gravel layers has been formed. For the coexistence of overflow and leakage， detailed technical measures have been prepared from the aspects of wellbore drifting ， casing running and cementation， and the target of “wearing shoes and hats” has been realized. The drilling technology of Well Ejandi-4 can provide useful experience for future oil and gas drilling in western Hubei.

Abstract:In order to evaluate the gas bearing property of shale around Xuefeng Ancient Land， Well Xiangtaodi-1， a shale gas geological survey well， was constructed in Yuanma Basin in 2019. The completed drilling depth was 1850.88m. the whole well was cored， and the average core recovery rate was 97.24%. XY-8 drilling rig is used in the construction， which adopts third spud hole structure， cooperate with gas logging and comprehensive geophysical logging technology， and optimizes the BHA， bit， drilling parameters and drilling fluid performance. Due to the instability and block falling of the carbonaceous mudstone in Niutitang Formation and the untimely adjustment of the drilling process， the downhole complications such as drill rod sticking， drill rod burying and drill tool breaking occurred. The screw motor sidetracking is adopted to bypass the obstacles， so as to solve the downhole problems such as sticking and burying. After sidetracking， continue to drill 806.87m with the same diameter until the completion of drilling. The successful completion of the well and the complex downhole treatment methods provide reference experience for the construction of geological survey wells in similar areas.

Abstract:Well Guiliudi-1 is a shale gas geological survey well in Luorong town block, Yufeng district, Liuzhou City, Guangxi province. The designed well depth is 2350m, and complex formations such as water sensitive strata are encountered during drilling. In order to improve the ability of solid-free drilling fluid to maintain the stability of hole walls in deep hole drilling in complex formation of shale gas geological survey， drilling fluid treatment agents such as the film-forming agent A and the plugging agent GFD-1 were added to the solid-free flushing fluid of PVA1788 system. Test and field application showed that the film-forming agent A had the function of reducing water loss without affecting the lubrication performance of the flushing fluid， or any obvious effect on the viscosity. The PVA1788 film-forming system solid-free drilling fluid has low filtration loss， good fracture sealing effect， reduces formation hydration expansion， and improves sloughing inhibition and prevention ability with film-forming； meeting the needs of maintaining the stability of the hole wall and safe drilling in the deep hole and complex formation. This paper has reference value for the popularization and application of solid-free drilling fluid in similar complex formations.

Abstract:In order to find out the lithology， sedimentary facies， thickness of organic rich effective mud （shale） and gas bearing property of the lower Carboniferous Luzhai formation in the Luorong favorable area in the east of Liuzhou， and obtain the relevant parameters of shale gas in the organic rich mud shale section， the Department of Land and Resources of Guangxi Zhuang Autonomous Region deployed a small-diameter geological survey well—Well Guiliudi-1 in Guizhong depression. With use of HXY-8B core drill and the multiple-section vertical drilling method， the well was drilled layer by layer； the pilot type reaming tool， together with the PVA1788 solid free flushing fluid system was used to ream the hole step by step with the casing set tier by tier， meanwhile， geological logging， electrical logging， cementing and drilling evaluation was carried out； which solved the drilling difficulties in deep mud stone， such as difficult coring， poor wellbore stability， over curvature of the borehole. The drilling technology can provide useful experience for shale drilling in the Carboniferous Luzhai formation in the area.

Abstract:Small diameter wire-line coring has irreplaceable advantages in shale gas geological survey wells， but also has major limitations. In regard to the application of small diameter wire-line coring technology in more than 10 shale gas investigation wells， this paper sums up the difficulties from geological condition， technical requirements， equipment， and supporting equipment， and put forward the optimization scheme from the aspects of wellbore structures， equipment configuration， coring technology， mud system and incident prevention. With the optimized drilling measures， good results have been achieved in the following shale gas investigation wells with the core recovery rate above 97%， the rig-month footage exceeding 400m， and the incident frequency below 2 times. It can be used as reference for drilling of future small-diameter shale gas investigation wells.

Abstract:Luyi Sag in the Southern North China Basin provides beneficial geological conditions for the formation and development of shale gas. The area belongs to the marine-continental transitional facies strata. The strata are complex and the structure is well developed； and there are many mudstone strata in Shanxi Formation and Shangshihezi Formation， which are prone to collapse and block falling during drilling. The designed depth of Well Luye-1 for shale gas survey in the region is 3506.5m. In view of the difficulties in drilling works， optimization of drilling equipment， bits and drilling fluid systems was conducted， and the technical measures such as mud wall protection， deep hole coring and anti-deviation were summarized. These measures have ensured the smooth implementation of drilling operations and form a set of shale gas deep well drilling technology methods suitable for marine and continental transitional strata in Luyi Sag of Southern North China Basin. It provides a useful reference for the next implementation of similar drilling engineering， as well as safe， high-quality and efficient development of shale gas.

Abstract:Since the coalbed methane（CBM） drilling construction was carried out in 2003， the geological prospecting team of Henan province has actively carried out technological innovation research， and developed special equipment such as large diameter wireline coring equipment and jet hole-expanding tunneling device. The construction technology research and practice of CBM parameter wells， horizontal wells， mining wells and cross-mining wells have been carried out， and the drilling construction technology system covering all types of CBM wells has been formed， which has accumulated rich practical experience and promoted the development of CBM industry in China. On the basis of summarizing the achievements of Henan geological exploration units in CBM drilling technology， this paper puts forward some suggestions for technical research on horizontal well drilling technology of high-efficiency CBM， pneumatic directional drilling technology and key technologies of tectonic coal development and drilling in combination with the development needs of domestic industries such as the gradual increase of CBM development depth， the gradual increase of goaf covered area and the failure to achieve breakthrough in tectonic coal CBM.

Abstract:Well Maye-1 is a venture exploration well deployed in the Wuxia fault zone of the Western uplift of Junggar Basin by Xinjiang Oilfield Company Limited. The purpose is to explore the prospecting potential of shale oil and conventional high porosity volcanic rock oil reservoirs in Fengcheng Formation. The designed coring length of the whole well was 275m with the actual coring length of 445m. The well is characterized with long coring interval， low coring efficiency in tight mudstone formation， easy core jamming in fracture developed sections， etc. In view of the formation characteristics in the area and the technical difficulties faced by the long coring interval of Well Maye-1， the long barrel core drilling process with the KT216 tool was applied in combination with diamond drilling at high RPM driven by bottom hole power. Compared with adjacent wells， Well Maye-1 had an increase of 1.79 times in comprehensive drilling efficiency over the long coring interval with the continuous coring length of 445m and the coring length per run of 41.97m， setting the record in the history of the area. It can provide reference for the subsequent implementation of continuous coring over long well sections in the area.

Abstract:Deep shale gas reservoir in Luzhou Block is featured of high formation temperature and pressure， leading to a high failure rate of 50% for the rotary-steering drilling tools and long average drilling time up to 50 days. Also， due to the wellbore trajectory design of “low kick-off point+high buildup rate” and the frequent adjustment of the long horizontal section trajectory， the frictional resistance during tripping of drilling strings and placement of casing was large. To address the above problems， several key technologies have been developed， including low-density-mud-based managed pressure drilling， the surface cooling system， and rotary casing placement. Field application showed that the density of drilling fluid was reduced from 2.20g/cm³ to 1.82g/cm³， the average ROP of the forth well section was 11.44m/h with an increase of 43%， the average drilling period was 27.1 days with a reduction of 51%， and the drilling speed and efficiency were significantly improved. The key technologies have good promotion and reference significance for improving the speed and efficiency of deep shale gas drilling projects in Luzhou.

Abstract:The depth of deep shale formation in Luzhou is about 4000m. It is typical high-pressure formation， where Shiniulan Formation drilled is a sandstone-rich mudstone. In this area， high-pressure formation gas was often encountered in drilling operations， increasing risks of gas-kick and lost circulation； meanwhile， pulsation wellbore leakage was observed while using high-density drilling mud. All these issues posed great challenges to drilling operations in this region. To address this issue， taking Well Y101H3-4 as an example， some wellbore plugging treatments were tested. Results showed that：①Typical wellbore plugging materials can not effectively plug wellbore leakage due to incompatible material-fracture sizes.②Based on drilling history of neighboring wells， reducing drilling mud density helped with wellbore plugging operations.③Oil-based cement plugging was the most effective method to deal with the formation with pulsated lost circulation at the prerequisite that proper mud density should be determined to prevent contamination due to contact between drilling mud and cement slurry. In conclusion， reducing mud density and use of oil-based cement plugging are the best method for pulsated lost-of-circulation in the Luzhou Block.

Abstract:Circulation loss in Liujiagou formation in Dongsheng Gas Field occurs frequently with large leakage amount and low treatment efficiency， resulting in long drilling periods. With geological data， logging data and electron microscope scanning， the fracture width of Liujiagou Formation was analyzed to determine the mechanism of fracture type leakage. The leakage data of Liujiagou Formation was summarized， the prediction model of leakage pressure was established through data fitting with the help of the correlation between leakage rate and differential pressure， and the transverse distribution profile of leakage pressure in Dongsheng Gas Field was drawn so as to provide quantitative basis for the optimization of circulation loss prevention technology. The calculation model of circulating pressure consumption and induced pressure is used to develop the wellbore pressure prediction method， and the influence laws of pumping rate， drilling speed， tripping-down speed and drilling fluid properties on wellbore pressure were analyzed to optimize drilling parameters. Rigid particles， fiber materials and sheet deformation materials were selected with optimized particle size gradation and component make-up ratio to develop the pre-pressure plugging-while-drilling system which provided. sand bed pressure bearing capacity exceeding 7MPa. Field application showed that the circulation loss in horizontal wells was reduced from 57% to 25.7%， the average circulation loss per well was reduced by 80.6%， the average leakage times per well was reduced by 88.1%， shortening the drilling periods.

Abstract:The Lower Shihezi Formation of Upper Paleozoic in Dongsheng Gas Field is a tight sandstone reservoir with good physical properties in some areas and natural production potential. There are problems of borehole wall failure and reservoir damage in the drilling process， and the reservoir damage caused by the combination of various factors hinders the release of gas productivity. In order to improve the natural production capacity of the reservoir， and increase the single well production， on the basis of reservoir permeability recovery， through analysis of the reservoir damage factors， the drilling fluid intrusion depth quantitative evaluation method was introduced to learn better the reservoir damage mechanism， and identify the low density， low water loss and soil-free phase and strong sealing drilling fluid as the solution. The waterproof locking agent and the tight pressure compound temporary plugging agent were selected in the laboratory to form a soil-free compound temporary plugging high acid soluble drilling fluid， increasing the permeability recovery to 91.11%， and reducing the mud intrusion depth by 46.28%. The drilling fluid was applied in the Jin-66 well area with the average single well production increased by 11%， and 3 wells realizing natural production； which has improved the effect of efficient exploration and development of tight sandstone reservoirs in Dongsheng Gas Field.

Abstract:For the efficient development of oil and gas resources in Bayanhetao New Area， research has been conducted on special shaped PDC bits. Based on well logging data， core assay and actual drilling data， the lithology analysis of the strata in this area is carried out， and finds that the drillability of the strata in the deep Cretaceous and the Archean gneiss strata is poor. The drilling results of special tooth bits in poor drillable formation in this area and the outer blocks are investigated， and show that the footage per bit in Cretaceous strata below 5000m and the Archean strata is small with low mechanical drilling rate， while drilling speed is remarkably increased in the Tarim Tahenan difficult area. The rock breaking mechanism of plane teeth， axe teeth， polygonal teeth and conical teeth is compared and analyzed， which provides theoretical support for subsequent optimization design of drill bits. Field tests were carried out on special-tooth bits， which significantly improved the penetration and ROP compared to conventional PDC bits. Twenty-one of the wells achieved “one-trip” drilling for the second well section with a total footage of more than 30000m. In short， according to the formation drillability， to improve the drill bit and formation compatibility through the optimal matching of plane teeth， axe teeth， polygonal teeth and cone teeth can significantly improve drilling efficiency.

Abstract:The Well Mengsudi-1 is a large-diameter key oil and gas geological survey well deployed by China Geological Survey in the Aaitegle Sag， Yingen-Ejinaqi Basin. In view of the geological conditions and technical difficulties in drilling in this block， optimization has been made for the drilling works of the Well Mengsudi-1 from the aspects of the wellbore structure， the drilling assembly， bit type selection and drilling technology. A drilling technical plan with the combination of “simplified wellbore structure+unconventional drilling assembly+conventional bit selection+strong inhibitory mud” was adopted and eliminated a series of problems such as high hardness， poor drillability， easy well deviation and wellbore instability in fractures in Mesozoic Bayingebi Formation and Upper Permian， leading to the successful completion of the Well Mengsudi-1. Drilling of the well was completed at 2763.66m with the diameter of 215.9mm， and the average drilling rate of 3.51m/h. The well successfully revealed the characteristics of Mesozoic and Carboniferous Permian rock assemblages and oil and gas potential， meeting various objectives and tasks with high quality， high efficiency and zero accidents.

Abstract:Exploration and development of shale gas， tight oil and gas， deep and ultra-deep well oil and gas， and deepwater oil and gas puts forward higher requirements for drilling tools and instruments. This paper introduces the new developments in drilling tools and instruments abroad. Drilling tools include efficient rock breaking bits（Aegis armor cladded bit， Crush & Shear? hybrid bit， adjustable smart-bit， StrataBlade concave diamond element bit and HyperBlade hyperbolic diamond element bit）， auxiliary rock breaking tools （Navi-Drill motor； NitroForce? high-torque， high-flow motor and 300℃-resistant positive displacement motor） and circulating subs（iCWD intelligent circulation drilling tool， IDisc intelligent circulation and disconnection tool， MOCS G2 circulation sub and JetStream? RFID circulation sub）； drilling instruments include rotary steerable tools（Lucida advanced-rotary-steerable tool， RST rotary steerable tool， VectorEDGE rotary steerable system， HALO high-performance rotary steerable system and NeoSteer at-bit steerable system） and MWD（TruLink high definitive dynamic MWD， IriSphere look-ahead LWD， HEX 200℃ high temperature LWD and QuestTM gyro while drilling ）. On this basis， the future development of domestic drilling tools and instruments is suggested. Finally， it is pointed out that China should complete the localization of core drilling tools and instruments as soon as possible， and continue to strengthen the research on low-cost alternative technologies to achieve economic and effective development.

Abstract:Near-bit MWD technology is one of the most promising new technologies in the field of petroleum drilling. It is characterized by near-bit geological and engineering parameter measurement while drilling， transmission， data interpretation and decision control， which can effectively improve the oil and gas zone intersection rate and reduce drilling cost. In this paper， the development and application status of near-bit measurement systems at home and abroad are introduced， and the working principle， structure composition and characteristics of the system are described. In order to meet the demand of small diameter drilling for near-bit measurement technology， the key technical problems to be solved in miniaturization design are put forward. They includes electromagnetic wave wireless communication anti-interference technology， small-diameter turbine power generation technology， downhole MEMS sensor technology， near-bit measurement data interpretation technology， etc， which provides technical basis for the research and development of small diameter near-bit measurement systems in the future.

Abstract:In order to study and improve the impact of fluid/solid erosion on the high-pressure manifold system in oil and gas drilling， according to the conventional manifold layout near the wellhead， this paper establishes the models for three angle elbows of 0°， 45° and 90°， and carries out numerical simulation of the internal flow field of the fracturing elbow according to the basic theory of computational fluid mechanics and with regard to the actual working conditions. Finally， the manifold layout structures for 0° and 45° fracturing installation angles are designed. According to the installation angles of the three elbows and the selection of the three elbow materials， the indoor erosion test was carried out， and the following conclusions were obtained： （1）At different installation angles， the greater the velocity of the fluid outlet with the increase of the number of strokes， the greater the velocity fluctuation of the bend position at any installation angle； if the velocity fluctuation is too large， the bend position will be seriously eroded； （2）The high-speed fluid erosion area is mainly distributed at the inlet of the pipeline near the wellhead fracturing head. In the case of two dislocations， the overall fluid velocity of the manifold gradually decreases from the outlet to the inlet； （3）The erosion area is mainly distributed near the inlet of the pipeline near the fracturing head. There are high erosion velocities at the five outlets of the fracturing head， and the velocity and pressure show a stepwise changewith a stable period in the middle and small pressure at the position with high velocity. At the installation angle of 0° and 45°， the impact velocity of the fluid will be small； （4）42CrMo has strong erosion resistance， and the selection of 42CrMo as the pipeline material will help to prolong the service life of the pipeline.

Abstract:The development and application of shale gas mud logging technology has enhanced constantly with technology research for more than ten years. Based on the evaluation demand of geological engineering integration technology， the paper has summarized a characteristic series of shale gas logging technology， namely，hydrocarbon source rock property evaluation by combination of the rock pyrolysis mud logging method and the natural gamma ray spectrometry mud logging method， shale lithology and brittleness evaluation by combination of element mud logging and natural gamma ray spectrometry mud logging， shale gas-bearing evaluation by combination of gas mud logging and carbon isotope mud logging， and shale physical property evaluation mainly by nuclear magnetic mud logging. Meanwhile， the paper predicts the development of shale gas mud logging technology. Nowadays，it faces the technical problems of complex horizontal shale gas well exploration targets， higher temperature of deep shale gas formation and lower pressure of normal pressure shale gas formation； thus， it is necessary to constantly improve the resolution of logging instruments， to strengthen innovation of multi-dimensional nuclear magnetic mud logging methods and other new technologies. In order to realize the three-dimensional portrayal and precise evaluation of shale gas formation， the big data resources should be used to develop intelligent mud logging technology so as to provide comprehensive technical support for efficient and high-quality shale gas exploration and development.

Abstract:Hydraulic fracturing is an effective technical method to exploit subsurface shale gas resources. To investigate the law of fracture propagation in shale hydraulic fracturing can provide proper guidance for high-efficient exploitation of shale gas. By using the extended finite element module of ABAQUS which is a large finite element software to investigate the influence of the position， azimuth and number of the initial fractures in homogeneous shale， and the structural direction， internal dip angle and lithology of the bedding shale on hydraulic fracture propagation at different ground stress deviations. The results show that for vertical hydraulic fractures， with the increase of the horizontal principal stress， the fracture is more difficult to propagate， the fracture propagation length decreases， and the initiation pressure increases. At the same injection volume， the length of hydraulic fractures formed by simultaneous initiation at both ends of the initial fracture is larger than that formed only on one side. When the initial fracture is located in the middle of shale with a direction of 45°， the fracture will deflect to the direction of the maximum horizontal principal stress， and the degree of deflection increases with the maximum horizontal principal stress. In the process of time-sharing multi-cluster fracturing， the propagation of fractures will interfere with each other， and it will greatly affect the attitude of fracture propagation and initiation pressure， but it has little influence on the fracture width at the injection point. For shale with horizontal and vertical bedding structures， hydraulic fracture deflection will be deflected to different degrees when the internal dip angle of bedding is changed， and the deflection degree of hydraulic fractures decreases with the increase of the internal dip angle of bedding. For shale with structural bedding in the direction of 45°， the deflection degree of hydraulic fractures increases successively in sandstone， coal rock and mudstone， and the fracture migration ratio increases with the maximum horizontal principal stress.

Abstract:The shale gas reservoir in the Zheng’an area is characterized with normal pressure， thin high-quality shale gas interval and large difference in horizontal principal stresses， leading to difficulties in forming complex fracture network， and in turn， restricting the increase of shale gas production. In view of the difficulties， the fracturing technology system， which mainly composes of multiple clusters of close cutting fracturing in horizontal well sections， fine fracturing design of horizontal wells， variable viscosity fracturing fluid systems with frictional pressure reduction， temporary plugging diversion and flowback fluid reuse， has been formed through the analysis of normal pressure shale gas horizontal well fracturing technology and application in the Zheng’an area in the context of the geological characteristics of the Wufeng-Longmaxi shale gas formation in the area， and referring to the advanced fracturing technology of shale gas in southern China. The technology has achieved good reservoir stimulation and production effect， which provides a strong support for the effective development of shale gas in the Zheng’an area.

Abstract:The tight sandstone of Liushagang Formation is one of the important targets for the exploration and development of the Fushan Oilfield in Hainan. Affected by complex structural evolution， the tight sandstone in this area has the characteristics of obvious thin interbedded sand and mud， low porosity， low permeability， and high temperature. In order to solve the problems such as high operation pressure， out-of-control fracture height， sand plugging， and low single well output and rapid output decline after fracturing in the past reservoir treatment， drawing on the unconventional reservoir volume fracturing technology， tests were conducted in four wells in the tight sandstone of Fushan Oilfield with the use of variable displacement and artificial barriers to control fracture heights， temporary plugging for fracture direction change， as well as optimization of fracturing fluids， and application of nano-synergy oil washing agents. The research results show that unconventional reservoir volume fracturing technology can effectively reduce the risk of sand plugging and improve the stimulation effect of tight sandstone reservoirs in Fushan Oilfield. The implementation of reservoir reconstruction techniques such as variable displacement， artificial barriers to control fracture heights， and temporary plugging for fracture direction change have effectively controlled fracture heights and increased the open degree of the reservoir. The application of the nano synergistic oil washing agent minimizes the damage of the liquid to the formation and fractures， exploits the effect of nano droplets to absorb and wash oil， and increases the stable production period of oil and gas wells.

Abstract:Ecological security and environmental protection are important issues concerned all over the world. In geological drilling， and oil and gas drilling and production， a lot of wastes are produced， directly influencing ecological security and environmental protection， and having a negative impact on national development and people’s life. In Russia， the problems have been researched by drillers with some results achieved. They have used two methods： the complex processing method and the magnetization processing method. The methods have certain innovation and practical significance. Using the methods， the wastes can not only be reproduced， but also can be used for the second time. It is suggested for us to pay attention to them and to study and discuss the methods.