| Si Yaoxian wellblock is located in the middle of Shanbei slope of Ordos Basin in Zhidan county. The main oil bearing formation is Yanchang group of Chang6 reservoir in Triassic. The degree on geological research is low at present,Reserves are unproved,the well group of test injection-production non-corresponding and waterflooding performs poorly in Si Yaoxian wellblock. On the basis of detailed study of reservoir geology,to carry out the geological reserves and evaluate dynamically developing well group. Formulate the limit of technical policy of water injection.The Chang6 reservoir in research area can be divided into four single layers,Chang 61, Chang 62, Chang 63 and Chang64. The Chang61 and Chang62 are the major oil layers, which sand bodies of reservoir are based on delta front underwater distributary channel deposits, the principle type of reservoir rock is fine-grained feldspar sandstone and inter-grain pores are the main reservoir space. Chang6 oil bearing beds are typical ultralow porosity and permeability reservoirs, with medium weak water sensitivity, weak acid sensitivity, weak velocity sensitivity and strong salt sensitivity characteristics. The major reservoir type is expansion lithologic reservoir.With the application of the volume method, Chang6 reservoirs superimposed oil bearing area is 26.47km2, and the proven oil geological reserves are 1143.95×104t, the recovery of water injection development is 15.64%. According to the demonstration of reservoir engineering, it is suggested to optimize the current flooding pattern to the inverted nine-spot rhombus pattern, with 150 m well row spacing and 500 m well spacing, and keep the reasonable formation pressure of 1.79 Mpa, the reasonable injection-production of 1.2, the reasonable production rate and liquid recovery rate is0.53% and 1.18% respectively.Through the system development of Chang6 reservoir in geological study,provide reliable basis for the development and deployment of the next step. |
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