Integrated Thinking in the Exploration and Development of Unconventional Petroleum and the Test Site in Songliao Basins
Fanli Meng and Yushen Du
Jilin University, Changchun, Jilin, China
Exploration and Development of Unconventional Petroleum requires mass capital investment and technological progress, which lead to the principle of cost leadership and integration of multi-technology. Thus the integrated thinking should be introduced.
One aspect of the integrated thinking is the integration of experts of different fields, technologies, and different stages of exploration and development. Over the last decade, integration thinking in Petroleum exploration and production (E & P) has been a worldwide trend among major oil companies: gathering professionals of all relevant fields, collecting all kinds of data, combining static and dynamic analyzing approach, facilitating in-time communication and close cooperation between different professions and sectors, optimizing through continuous feedback, in order to solve the key problems under a goal-oriented and systematic thinking. Due to the progress of modern technology, each technology can extend its contribution to the upstream and downstream. In this way the integrated criterion can pick the shortest path, and achieve an economical development of unconventional oil and gas with the most suitable technology.
In shale gas and shale oil production, the costs of drilling and reservoir stimulation count for 80% of the total cost. Due to the heterogeneity of shale reservoir and the necessity of manually improving permeability, it is necessary to consider the geological and reservoir conditions and stress situations when choosing proper wellbore direction, deciding whether and how to stimulate reservoir and how to design the related completion plan. Finally, drilling program should follow the requirement of completion and reservoir stimulation.
On the other hand, the integrated thinking emphasizes integrated development of tight gas, shale oil and gas, as well as conventional oil and gas. The shale gas reservoir in U.S. does not consist of shale only, in strict sense, but also carbonates, siltstones, tight packsand. Furthermore, the existing large shale gas production areas are located within the basin of conventional Petroleum. The thirty-fourth World Petroleum Congress advocates the integrated exploitation method of shale gas, coalbed methane and tight gas in order to improve the exploiting efficiency and to avoid the waste of resources.
U.S. shale gas was fond mainly in marine of foreland basins and cratonic basins. China introduced and imitated this mode primarily in marine of Paleozoic Era also. The main testing site was built in Sichuan, Chongqing, Guizhou and Hubei and other places of southern China. Though having achieved satisfying results, there are some problems, such as dealing with the strongly deformed strata, the unfavorable ground conditions, technical difficulty in fracturing and incomplete collecting and transportation infrastructure. Besides, more attention was paid to construction while reservoir evaluation was neglected; more emphasis was put on completion design while optimization on multiple factors of well trajectory of was neglected, etc.
Songliao Basin, as an extra large Cretaceous oil-gas-bearing basin in China, is of great importance in shale oil and shale gas exploration. The Cretaceous Oceanic Anoxic Events have caused mass of carbon buried in geological history. That time the main part of Chinese territory was within this Cretaceous landmass. The Chinese Ministry of Land and Resources, collaborating with Petro-china, Sinopec and Northeastern University, preliminarily investigated Songliao Basin and some of its peripheral basins, and deemed that there is a good prospect of shale gas in Shahezi group, the first and second segment of Nenjiang group, and the first and second segment of Qingshankou group.
Due to the anisotropy of shale gas reservoir, shale gas basins are quite diversified. Different technology modes should be built for exploration and development of different basins. The auther argues that it is necessary to initiate a testing site in the Songliao Basin. During the process of study and the drilling, applicative techniques can be introduced and applied to reservoir stimulation. Hence a series of techniques for integrated exploration can be developed. With the abundant organic-rich shale, completion pipeline and processing facilities, Songliao Basin will be refreshed and become a sustainable petroleum production zone.
AAPG Datapages/Search and Discovery Article #90180©AAPG/SEPM/China University of Petroleum/PetroChina-RIPED Joint Research Conference, Beijing, China, September 23-28, 2013