2 1 century ago, this area experienced several rounds of exploration, and * * * 2 1 shallow, medium and deep exploration wells were implemented, and only some wells obtained low-yield industrial gas flow.
1) Pre-exploration stage: 1955 ~ 1965,1:200,000 surface geological survey,1:50,000 structure detailed survey,1:500,000 gravity and magnetic survey, Shuangshimiao structure and gold deposit were discovered. 1965 to 1980 for simulated magnetic tape seismic exploration, and start drilling from shallow to deep. Well Chuan 1 was drilled in Shuangshimiao structure, with a footage of 2525.08 meters, and weak gas was shown in Lower Jurassic and Upper Triassic. Well Chuan-25 was completed in Fujiashan structure with a footage of 2,865.5 meters, and industrial-grade potassium-rich brine was found in the fifth member of Jialingjiang Formation. Well Chuan 64 was completed in watershed structure, with a footage of 5005 meters, and no oil and gas was found. 1980 ~ 1990, with the great breakthrough in natural gas exploration of Carboniferous Huanglong Formation in eastern Sichuan, oil and gas exploration in this area once became a hot spot, and a two-dimensional digital seismic survey covering the whole area was carried out, with a network of 2km×4km in some areas. The detailed seismic survey of Dongyuezhai structure was completed, and the survey network reached1.5km×1.5km. The experimental 3D seismic exploration of 25.6km2 was carried out in Shuangmiaochang (Schiller) structure, and the 2D seismic exploration of 959.93km was completed. During this period, Dongyuezhai structure encountered Chuanyue 83 well, and only the second member of Feixianguan Formation of Lower Triassic obtained small-scale fractured gas reservoirs. Later, in order to further evaluate the gas-bearing property of Dongyuezhai structure, Chuanyue 84 well was drilled, and gas was only shown in Maokou Formation. The former China Petroleum and Natural Gas Group Company completed three ultra-deep wells exposing Carboniferous in Shuangshi 1 and Schiller 1 and 2. Shuangshi 1 Carboniferous (4m) perforation acidized into dry layer, and oil and gas showed in shallow Jurassic. Schiller 1 Well is acidized by perforation, and a small amount of water is found in Maokou Formation. Upper Permian and Carboniferous are both dry beds, producing micro-gas. Well Schiller 2 achieved a low-yield natural gas production of 1207m3/d in the middle of the well depth test of Upper Shaximiao Formation in Jurassic, and produced water in Maokou Formation after the completion test. In addition, the second geological brigade completed the drilling of well Bei 2 rich in potassium brine in Jialingjiang Formation.
2) Exploration stagnation stage: From 1990 to 1999, oil and gas exploration is in a relatively stagnant stage. During this period, only 1 1 2D seismic lines were implemented in Qingxichang structure, and Chuanfu 85 well was drilled in Fujiashan structure, but no oil and gas results were obtained. In the southeast corner of the block, PetroChina completed the drilling of Well Qili 23 with Carboniferous as the target formation, only Maokou Formation saw gas and Carboniferous tested water.
3) Main problems: structural traps were the main exploration targets in early exploration, only the main target layer of Carboniferous Huanglong Formation was ignored, and oil and gas display in other horizons was insufficient. At the same time, due to the large annual acquisition span, irregular layout of measuring network, great difference in acquisition system and method, the signal-to-noise ratio and resolution of early seismic data are not high, which can not meet the basic data requirements of lateral reservoir prediction.
Discovery and Enlightenment of Puguang Atmospheric Field in 4.2.2.2
2 1 century, under the guidance of the upstream development strategy of "stabilizing the east, developing the west, breaking through the south and opening up overseas", China Petrochemical took the Xuanhan-Daxian exploration area (area116km2) in northeast Sichuan where Puguang gas field is located as a strategic development zone in 2000. Through solid basic geological research, strengthening exploration technology research, adjusting and rationalizing exploration ideas and innovating exploration concepts, a major breakthrough in Puguang gas field was achieved in only five years, and the largest marine gas field in China was discovered. Up to 2007, the Xuanhan-Daxian exploration area where Puguang gas field is located has accumulated proven natural gas reserves of 38 12.57× 108m3, and Puguang, Dawan and Daxian have been discovered. At the same time, four gas-bearing structures, such as Laojun, Qingxichang, Shuangmiao, Maobaxi and Shuangmiaochang, were obtained, which realized the high speed of "two-year major exploration breakthrough and three-year overall exploration in Puguang gas field" and achieved great social and economic benefits.
The efficient and rapid discovery of Puguang gas field benefits from solid basic geological research, innovation of exploration concept and progress of exploration technology. At the same time, the innovation of exploration management mode also provides strong support for the discovery of this gas field.
In 2000, the southern offshore oil and gas exploration project management department took over the exploration work in Xuanhan-Daxian block. Through the detailed study of the previous data, the good exploration prospect of this block is affirmed, and it is considered that the failure to break through in the previous period may be restricted by "only the Carboniferous main target layer" and "taking structural traps as the main target layer", and the lack of exploration technical means is also an important reason. Therefore, since 2000, a lot of basic research has been arranged, and the exploration idea with structural lithologic traps as the main goal has been formulated. The basic projects arranged in this period include: review of old data, comprehensive study of Carboniferous-Triassic petroleum geology in Xuanhan-Daxian area, study of Permian-Triassic fine sequence stratigraphy and sedimentary facies, repeated processing of old seismic data, fine structural interpretation and target evaluation. At the same time, a new round of high-resolution seismic acquisition and processing of stratigraphic and lithologic traps is deployed.
One year later, thanks to the high-precision seismic data processing and interpretation, the first batch of exploration wells were deployed according to the new exploration idea, including Puguang 1 well and Maoba 1 well, that is, the structural-lithologic compound trap with the reef of Changxing Formation-Feixianguan Formation and the beach porous dolomite reservoir as the main exploration targets. 200 111On October 3rd, the first exploration well Puguang1deployed in Dongyuezhai-Puguang structure in Xuanhan-Daxian area was officially drilled. Two months later, on October 9th, 2002 1 65438, the exploratory well Maoba1deployed on the structure of Maoba Oilfield was drilled. In June, 2003, 5438+ 10, Maoba 1 well was the first to achieve high production in the fractured reservoir of Feixianguan Formation. From July 27th to August 20th, 2003 10, routine tests were conducted in the 56 1 0.3 ~ 5666.24m interval of the second member of Feixianguan Formation in Puguang1Well. The Puguang 1 well encountered the reef-beach facies 26 1.7m high-quality dolomite reservoir of Changxing Formation and Feixianguan Formation, which announced the exploration discovery of Puguang atmosphere and confirmed the prospector's prediction.
After the major discovery of Puguang 1 well, exploration and evaluation began rapidly. Through careful evaluation and research, three evaluation wells, Puguang 2, Puguang 3 and Puguang 4, have been deployed and implemented. Well Puguang 2 was drilled on September 26th, 2003, and reached 5353m on May 6th, 2004. High-quality dolomite reservoir of Changxing Formation-Feixianguan Formation was drilled to 4 10.2m, and high-yield industrial gas flow was obtained by multi-layer test of Feixianguan Formation and Changxing Formation. Well Puguang 4 was drilled to 6 122 m on February 27th, 2003 and 6122 m on February 30th, 2004. The high-quality dolomite reservoir of Feixianguan Formation was 233.9 m, and Feixianguan Formation also obtained high-yield industrial gas flow.
In order to accelerate the discovery of Puguang gas exploration and realize three-year overall exploration. In 2003-2004, 3D seismic data acquisition with 456.06km2 high coverage, artillery offset and wide azimuth was deployed. Complete data processing and interpretation as soon as possible. The second round of evaluation wells in Puguang Gas Field based on the new 3D seismic data are Puguang 5, Puguang 6 and Puguang 7 (Pingping 1). Changxing Formation and Feixianguan Formation have encountered extremely thick high-quality dolomite reservoir and high-yield natural gas flow, and the error between predicted depth and actual drilling depth is less than 0. 15%, and the absolute error between predicted porosity and logging interpretation porosity is less than 0.32.
Well Puguang 5 was drilled on February 1 2005, and it was drilled to 6095.59 meters on October 29, 2005. The high-quality dolomite reservoir of Changxing Formation-Feixianguan Formation was drilled to 356.3 meters, and Changxing Formation obtained high-yield industrial gas flow.
Well Puguang 6 was drilled at 5438+/kloc-0 on June 23, 2005, and at 55 10m on August 20, 2005. High-quality dolomite reservoir of Changxing Formation-Feixianguan Formation is 4 1 1.2m, and high-yield industrial gas flow is obtained by multi-layer test of Feixianguan Formation and Changxing Formation.
Well Puguang 7 Ping 1 encountered high-quality dolomite reservoir of Feixianguan Formation 175.7m, and the gas production of Feixianguan Formation 1 (5571.70 ~ 5590.70 m ~ 5590.70 m) was 28.76×104m3.
In February 2006, it was accepted by the expert group of the Mineral Resources Reserve Evaluation Center of the Ministry of Land and Resources. In puguang gas field, the cumulative proven reserves calculated by Pingping/kloc-0 of puguang 1 well, well 2, well 3, well 4, well 5, well 6 and well puguang 7 reach 25 1 0.7×108m3, and the technically recoverable reserves are 4 1km2.
The discovery and verification of Puguang gas field not only greatly eased the shortage of oil and gas resources in China, but also became an important replacement position of oil and gas resources in China, which provided important enlightenment for oil and gas exploration of marine carbonate rocks in the future.
Enlightenment 1 scientific and correct decision-making is the premise of exploration and discovery.
1998 After the establishment of China Petrochemical Group Company, from the strategic height of alleviating the prominent contradiction between oil and gas supply and demand at home and abroad and ensuring national economic security, on the basis of widely listening to and adopting the opinions and suggestions of well-known domestic experts, the strategic policy of "actively preparing for the south" was put forward, and the Southern Offshore Oil and Gas Exploration Project Management Department and the Southern Exploration and Development Branch were successively established, giving sufficient attention, investment and specific guidance to the oil and gas exploration in the South. After the discovery of Puguang gas field, China Petrochemical timely adjusted the domestic oil and gas exploration and development strategy from "preparing for the south" to "developing the south", intensified exploration efforts, accelerated exploration pace, and conducted specific command and coordination. It is the scientific decision-making and correct leadership of China Petrochemical Corporation that brought about the great discovery and rapid exploration of Puguang gas field.
Revelation 2: The innovation of theoretical understanding is the basis of exploration and discovery.
Only innovation can make a breakthrough. In a field with a relatively high degree of exploration and no breakthrough, if we continue to follow the old path of our predecessors, there will definitely be only one "dead end". We must take the experience and lessons of our predecessors as the starting point of progress, dare to go out of the previous understanding, dare to stand on the shoulders of our predecessors and break the previous "conclusion", and realize fundamental transformation and thorough innovation in exploration theory and geological understanding, so as to have the hope of exploration breakthrough.
It is the innovation of geologists in a series of oil and gas geological theories that laid the foundation for the discovery and exploration of Puguang gas field.
Break through the previous understanding of Kaijiang-Liangping trough.
The sedimentary model of platform shed area and platform margin area is established, which is beneficial to the development of reef-beach facies reservoirs.
The "three-element reservoir control" model of deep carbonate rocks is established.
The model of "multi-stage structural superposition controlling multi-element and multi-stage hydrocarbon generation in superimposed basins" is established.
A composite reservoir control model of deep carbonate rocks is established.
The oil and gas distribution and target classification evaluation method of marine deep carbonate rocks in southern China are established.
Revelation 3: The innovation of technical methods is the support of exploration and discovery.
The discovery and implementation of Puguang gas field benefited from the innovation of technical methods. During the Tenth Five-Year Plan period, a series of targeted and applicable seismic and wellbore technical methods were formed by tackling key problems through technical methods, which provided strong support for the discovery and implementation of Puguang gas field and also had reference significance for deep carbonate oil and gas exploration in mountainous areas of China and even the world.
Seismic exploration: high-precision seismic acquisition technology in mountainous areas with reservoir-oriented acquisition design, saturation excitation, high-precision positioning and high-density sampling as the core, high-precision seismic imaging technology with eliminating near-surface effect, high-precision prestack imaging and high-resolution imaging of reservoirs as the core, and determination of physical parameters of carbonate rocks, analysis of geophysical response characteristics of reservoirs, establishment of reservoir seismic identification model, restoration of paleogeomorphology, seismic identification technology of reef development area, spectral imaging technology of reservoir prediction and its effectiveness.
Wellbore technology: unconventional series of wellbore structure, anti-deviation straightening technology, rapid drilling technology and small gap cementing technology in deep wells are adopted to optimize wellbore structure and improve ROP; On the basis of studying the reservoir characteristics and reservoir damage mechanism of marine strata, the broad-spectrum shielding temporary plugging technology and supporting plugging removal technology for protecting oil and gas reservoirs are developed. The introduction of vertical drilling technology and air drilling technology has also achieved good results in practical application; The gas testing technology for ultra-deep, high-pressure, high-temperature and high-H2S gas reservoirs has been formed, and the gas testing work for the 44th layer of Well 14 has been safely completed within three years, and all the data have been accurately obtained. The acid fracturing technology for ultra-deep, high-pressure and high-hydrogen sulfide gas reservoirs has been initially formed, which laid the foundation for the embodiment of the real productivity of gas wells.
Revelation 4: The innovation of exploration ideas is the key to exploration and discovery.
Correct pioneering thinking is the cornerstone of our success. On the basis of solid basic research, geological understanding and technical method innovation, the idea of oil and gas exploration in Xuanhan-Daxian area has changed from structural traps as the main exploration object in the early stage to "structural-lithologic compound traps with reef-beach porous dolomite reservoirs as the main exploration object". This innovation of oil and gas exploration idea is the key to the discovery of Puguang gas field, which fully embodies that "the new exploration area should learn from the exploration experience of mature exploration areas and become mature."
Revelation 5: Innovation of management mechanism is the guarantee of exploration and discovery.
It is the only way for modern enterprise management to ask for efficiency and benefit from management.
At the beginning of implementing the strategy of "preparing the south", China Petrochemical Group clearly put forward the management system and operation mechanism of exploring "group decision-making, project management, market-oriented operation and socialized service" in the southern new area. The establishment and implementation of this management system and mechanism has two major advantages: first, centralized decision-making, unified coordination and unified command on major issues, which has the advantage of concentrating on major issues; Second, according to the project management in the specific implementation, the construction team and scientific research force all enter the market, which has the advantage of using the market mechanism to allocate resources. According to the management system of China Petrochemical Company, combined with the characteristics of offshore oil and gas exploration, such as complex objects, long front, scattered operations, large liquidity and multi-disciplinary joint operations, the management mode and operation mechanism adapted to its own characteristics have been gradually established.
The strong scientific research motivation inspired by the innovation of scientific research management mode is the premise of theoretical understanding and technical method innovation.
With the strong support of the headquarters of the Group Company, the offshore oil and gas exploration in South China adheres to the scientific research ideas of "marine facies" and "big technology". While strengthening the construction of marine scientific research strength in South China within China Petrochemical Company, it also strengthened the close cooperation and joint research between universities and research institutes, and established a strong integrated scientific research support system in Industry-University-Research. Research institutions at all levels give full play to their own advantages, and each has its own emphasis on specific research content, which constitutes a pair.
Scientific and standardized project management mode provides a strong guarantee for high-quality engineering construction.
Taking bidding and contract management as the core, the regulations and rules on bidding and contract management were formulated and promulgated, which standardized the operation of all work in the bidding and bidding process. Strengthen market access management and construction team assessment to ensure that qualified teams are more applicable and advanced, and the structure is more reasonable and diverse. The design system of Party A has been improved, and the project quality has been ensured. The supervision and management of the whole project process has been strengthened, which is mainly reflected in two aspects: ① In the project bidding, the qualified supervision provided by the tendering unit is regarded as one of the bidding conditions, which creates conditions for further improving the supervision quality, expanding the scope of supervision selection and strengthening supervision and management; (2) Hire full-time supervision companies to participate in on-site supervision, strengthen safety management, ensure exploration benefits, gradually establish and improve various safety management systems, and implement the responsibility system for production safety at different levels.