Sand Control Techniques in Shengli Oilfield

ABSTRACT Shengli Oilfield has been developed for more than twenty years. The problem of sand production has existed since its development. About one third of the total oil wells in Shengli have sand problems. This paper describes the techniques of sand control in Shengli Oilfield. Three sections are presented: —Chemical sand control;—*Sand control in steam soaking wells;—Mechanicals and control. In the past twenty years, twenty-six fields have been put into production in Shengli. The amount of cumulative oil production has reached 240 million tons. The geological structure of Shengli Oilfieldis very complicated, oil fields are located in many depression basins. The reservoir rocks are Tertiary sandstones of younger geological age, very unconsolidated and produced with different degrees of sand production troubles. There are sand problems in 2/3 of the reservoir and 1/3 of the producing wells in Shengli Oil Field. Some of these wells have been plugged by sand to a height of 98 — 271 meters. Some of the flowing wells produce oil with a sand content as high as 40% from the start of the production. Due to the severe sand problems some wells cannot even be tested for reservoir parameters in some new exploration areas. For example, in Gudao Field the averaged cumulative sand production per well reached 25 cu. m. and the total cumulative amount of sand produced reached 20000 cu. m. during six years of production: i.e. 11 cu. m. sand per 10,000 t. of oil. Under such circumstances, the research work on sand control techniques and its generalized application have great significance in maintaining peak oil production in Shengli Oilfield. Shengli Oilfield has a history of 20 years of sand control. Because of the very complicated geological conditions such as multiple faults, great differences in their vertical and horizontal distribution and the wide range of formation permeabilities and oil viscosities existing in various oil pools and very different bottom conditions occurring in the sand producing wells, various sand control techniques are needed for effective treatment. These techniques in Shengli Oilfield are characterized by simplicity, effectiveness and economy. Two types and 8 techniques are mainly used and 3,965 operations had been conducted by the end of 1984. The sand control techniques of Shengli Oilfield are described in following three sections: —Chemical sand control;—Thermal well sand control;—Mechanical sand control.