Research On Transform Technology Of Low-permeability Reservoir In Funing Formation Qintong Depression

Low-permeability reservoir is one of the main types of oil and gas reservoir in china. Fracturing is the primary methode to transform the low-permeability oil or gas reservoir which had made great progress in china recent years. But there are still many problems which have constrained the fracturing technology to practise. And then validity development of low-permeability oil fields was effected. Funing Qintong Depression is one of the low-permeability reservoir which is hard to develop. It has many properties,such as strong non-homogeneous, high clay content, natural fracture and reservoir characteristics of sensitivity and strong. There are also many question such as large fluid loss, low success rate, difficult to add sand , low flow back rate, which directly constrains development of low-permeability reseroir Funing Qintong Depression.This paper begins with the studing on pre-fracturing wells, analysis many fracturing problems of Funing reservior by using many technolgyies such as statistical analysising, min-fracturing analysising, pressure matching and so on. And then a series of test was conducted,such as sensitivity test which define the type of fluid filling in well to aviod formation damage; rock mechanics test with which mechanical parameters were measured and the rules of rock broken were analyzed,and then operating parameters were corrected; Fracturing fluid optimization tests which optimized suitable fracturing fluid systems based on the above studies for transform of Funing reserv including cross-linking agent optimization test, anti-swelling agent optimization test, cleanup additive agent optimization test, viscosity-temperature relationship test and core damage test.Finally with the result of these tests a set of fracturing fluid system was optimized which suit for all kinds of temperature and low damage fracturing fluid systems were optimized for three type of formation; proppant conductivity test which used seven proppants which collected from current market to run an experiment such as effection of closure pressure experiment,effection of fracturing fluid experiment , effection of particle size experiment and effection of embedded experiment.With these experiments the best proppant and the condition to form high conductivity fracture were obtained. Then many techniques were studied based on the result of the experiments and character of Funing formation such as fracture hight controlling technology, fluid leaking off controlling technology, assembling ceramic technology, fluid flowback technology and so on. Finally, on the basis of research's results, six wells of the fracturing test were done which achieved a more satisfactory result. The results of this study will not only improve fracturing technology on Funing low-permeability reservoir, provid a reliable technical basis, but also provide a strong reference for other low-permeability reservoir's fracturing.