The Application Of Fine Reservoir Description Technology To Oil Field Secondary Development

Karamay conglomerate oil field is the firstly discovered large oil filed after the founding of New China. Also, it is one of the large rare conglomerate oil fields in the world. For the long time production, most of the wells there have already entered a non-normal exploitation phase of the later primary development facing the serious problems such as high water cut, high recovery, big production decreasing, well condition deteriorating and interformational and planar contradiction. For the purpose of enhanced oil recovery, new theories and new methods will be used to get detailed information of reservoir.In this paper, Triassic Keshang zone reservoir of in Erzhongxi block in Karamay Oilfield was made as the research object. Subzone correlation was conducted to the main target of S₅ formation of Keshang zone. It was done by comprehensive application of such data as core, logging, mudlog, sample analyzing production performance guided by sedimentology, reservoir engineering and numerical simulation technologies. Sedimentary texture classification was developed on the base of fine interwell layer classification and correlation and study of sedimentary microfacies. Furthermore, petroleum reserve allocation and three-dimensional geologic modeling were done by logging data processing and interpretation in the stratigraphic framework of the constraints. Combined static geologic research results with dynamic production data, reservoir characteristics research and stochastic modeling were conducted and remaining oil distribution was at the same time made definite. All of these provided a solid technical foundation for the redevelopment program design.Research obtains several innovative achievements. The S₅ sand zone was firstly classified to 6 architectural units of S₅^1-1,S₅^1-2,S₅^1-3,S₅^2-1,S₅^2-2,S₅^2-3 from above to below, and was finely described combination relation of inner architectural units, which provided important reference with interwell subzone connectivity, movement law of fluid and remaining oil distribution. Log interpretation chart and electric property standard creative developed by the rare standard logging and core analysis have a good guide of fine reservoir description and parameter calibration to the old oilfield lacking of composite log data. Through the full use of well testing and production performance, initial oil in place (OOIP) in 6 sedimentary texture units was double-calculated and net growth of OOIP came to as much as 40.6×10⁴t. Three-dimensional geological reservoir model was built by using of stochastic modeling software, RMS while the production model and injection/production corresponding model were established by using of numerical simulation software, Eclipse. By the application of integrated analysis of development geology and reservoir numerical simulation, remaining oil distribution was ascertained where S₅¹ sand was defined as abundance zone. The ultimate oil recovery was confirmed as 45% and quantity of remaining recoverable oil was 96.11×10⁴t. Remaining oil mainly lay in the S₅¹ sedimentary texture unit of the reservoir top.Technical strategy and development adjustment program were proposed based on fine reservoir description of S5 sand. Also, well pattern adjustment program was optimized here, which had a positive effect to oil field production.