Sandstone Fracturing - Gravel Pack Sand Control Technology Research

The oil wells in medium and low permeability sandstone formations of Xin Jiang oil field have low productivity and begin to produce sand after producing several or more than ten years. So, some sand control methods must be used in the wells. The chemical sand consolidation method and downholl gravel pack inner casing used before had good results, but all the methods induced low or very low productivity.Through investigation on the sand control techniques and oil well stimulation methods both home and abroad, the author studied one new technique that can not only control sand production but also can stimulate the oil wells, that is the complex technique including hydraulic fracturing and gravel packing. The new technique is called fracpack. The main completed works are as follows.1. Studied the formula used to calculate the productivity of oil well that is completed with downholl gravelpack inner casing. Analyzed the main parameters affecting the productivity of wells under the conditions of different permeability and different perforation methods. And the main reasons of high skin factor induced by downholl gravelpack inner casing have been found also.2. Studied the formula used to calculate the productivity of oil well that is completed with fracpack . Analyzed the main parameters affecting the productivity of wells under the conditions of different permeability and different perforation methods. And the main reasons of low skin factor induced by fracpack have been found also.3. Studied the mathematical models and calculating methods for the fracture geometry with pseudo-three dimensions. And studied the mathematical models and calculating methods for the temperature distribution in fracture. All the works above formed the basis for the design of fracpack.4. Studied the design method for fracpack including wells and payzones selection, fracturing design, sand control design and so on. The application shows the research is good and correct. So, the theory and design method for sand control with both fracturing and gravelpack is very important to oil field development and oil production.