西南石油大学学报(自然科学版)

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Research on Formation Pressure Predictionin in Ansai Area Infilling

WANG Yongming1,2*, WU Xuesheng1,2, ZHOU Wenjun1,2   

  1. 1. Research Institute of Oil and Gas Technics,ChangQing Oilfield Company,PetroChina,Xi′ an,Shaanxi 710018,China
    2. State Project Laboratory of Low permeability Oil and Gas Exploration and Development,Xi′ an,Shaanxi 710018,China
  • Online:2016-08-01 Published:2016-08-01

Abstract:

Ansai Oilfield infill experimental zone is located in the mid-west Wangyao zone. After long-time development,the
composite water cut reaches 58.9%,geological reserves recovery degree 11.8%;formation pressure system is in disorder,and
natural fracture and fracture cracks co-exist. Therefore,the prediction of formation pressure of encryption test wells is difficult
and drilling safety is at risk. Based on the analysis of Ansai experimental area and on the basis of geological characteristics,we
studied the difference between formation pressure in the process of water injection and the original formation pressure,trying
to accurately determine reservoir pressure distribution water after injection. We introduced the seepage theory of fractured
formation after water injection in the process of the formation pressure prediction,and suggest calculation method for infilled
wellbore formation permeability tensor of complex crack formation and prediction methods for infilling of formation pressure.
Applying these methods to the prediction of formation pressure of experimental zone in Ansai produced highly accurate results
that satisfy the need of safe drilling fluid density window The influence of the characteristic of cracks on infill well formation
pressure is also analyzed,which can provide practical guidance for infill well drilling safety.

Key words: Ansai Oilfield, infill well, formation pressure, safe drilling, density window

CLC Number: