| Jing 11 fault Block of Bieguzhuang Oil Field is located at the southern portion of the Hexiwu structural zone in Langgu sag of Jizhong depression, Yongqing county, Hebei province. Jing 11 is very important for the sustainable development of the 4th Production Branch of Huabei Oil Field since it is the major block with the oil-bearing area 3.0 km2, the OOIP is 1182 X 104 t and the reserve is 612.8 X 10~4 t roughly. The achievements have been attained by the early water injection, 3-subdivision of development series and strong exploitation. It was recognized as High Efficient Development Oil Field by PetroChina both in the periods of "75" and "85". However, many challenges such as early water breakthrough, casing deformation and low pressure maintenance had occured at the mature phase of this block with the oil rate of 480t/d and the recoverable recovery factor of 75%, the decline rate went up to 20%. It is urgent to deploy the comprehensive geologic study so as to improve the production performance further accordingly.It belongs to more layers fault-structure sandstone oil reservoir. By analyzing development characteristics of different development phase and utilizing advanced technology such, micro structure, inter No. 5 fault sealing, the relationship between different stratum, characteristics of reservoir unit division and numerical simulation etc, this research gains five aspects of fruit:The fault block is a micro structure with two arches and one sag. Injection-production well pattern is adjusted on sand I in the North of fault block, so it keeps 80 tons daily rate, 75% water cut. Especially Gaojing375 well produces 30 tons high daily rate on sand I by perforating.Eight low resistance oil reservoirs with 0.9 square kilometersoil-bearing area and 118 X 104 tons geological reserves are found by researching fault sealing. Then one low producing wells are perforated, four wells is drilled. Finally, this field gains 40 tons daily rate, 5 X104 tons cumulative production and 3~5 relay layers per well.70% wells with water flooding and casing change locate on the top of sand I in Jingll fault block. An unconformity between the top of sand I and overburden layer S3 is found by means of stopping water flooding to inject-water well, decreasing water and low velocity of casing change. Reservoir is divided to five kinds of sedimentary units (A, Bl, B2, C, and mudstone) according to the characteristics of reservoir and subtle reservoir research.The remaining oil distribution law is researched by means of numerical simulation and synthetically judgment of pay zone. The remaining oil distribution is classified four kinds of types (uncontrolled by well pattern, baddish physical characteristics or baddish percent of producing reserves, faulty injection-production pattern and well-to-well pressure equilibrium zone). The different types' produced pattern was analyzed. Scheme 3 is chosen from four kind of remaining oil producing schemes, increasing production and reducing water by drill new well, synthetically utilized well pattern, perforated well, plugging, and lift liquid.Jingll fault block development effect is improved by subtlegeological research. Water flooding recovery increases from 38. 7% to 51. 8%.Recoverable reserves increases 155.7X104 tons. Oil reservoir naturaldecline rate is 15% and lower 5% than before. Daily rate is 401 tons. Watercut is 85% at present, lower 1.5 than before. |
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