The Evaluation And Optimization Of Low Damage Drilling Fluid System Based On Kuche Area Within Tarim Gas Field

The structural formations of Kuqa Basin in Tarim are very complex. The development of evaporite beds, high pressure brine water layers, high pressure oil/gas layers and broken stratus and the influence coming from high ground stress and high formation angle make the piedmont structure abnormal high pressure formation and high collapse stress strata widespread. Owing to the complexity of the drilling geological being bad for the reservoir and drilling accessories, it is urgent to select out low damage drilling fluid suitable for kuqa area.In this paper, a large number of analyses and researches have been done about the Tarim Gas Field, especially about the problems associated with drilling fluid such as water loss, carrying cutting and big friction existing in Kuqa piedmont region drilling process, and about the problems of hole caving, poor drilling fluid performance and formation damage when applying the conventional drilling fluid system in different blocks and different stratum in Kuqa area. According to the above problems, through the indoor evaluation research for low damage drilling fluid in experiment center of Tarim oilfield, this paper develops three sets of low damage drilling fluid systems. They are high temperature resistance water-bases drilling fluid system which has good inhibitive ability and anti-wear effect, high density oil-based drilling fluid whose advantages are good stability and reservoir protection effect, and composite organic salt drilling fluid system which good at rejection and antipollution performance.The three sets of low damage drilling fluid systems have not appeared any drilling problem such as sticking in Kuqa area field application and meet the requirements of the deep well and ultra deep well drilling in kuqa block on the whole. In view of the characteristics of three kinds of low damage drilling fluid systems in field application and requirements from different blocks and different stratum, we optimize the drilling fluid systems which adapt to different formation conditions.The research results of this paper will be helpful to make Kuqa piedmont block drilling operation quickly and securely.