Study On Gas Layer Identification Method Based On Dipole Shear Wave Logging Data

Shihezi and Shanxi formation reservoir’s porosity and permeability of Upper Paleozoic Permian in Sulige gas field are very low. The natural productivity of this area is not significant. Commercial productivity could not be obtained unless hydraulic fracturing or acid fracturing is applied. It has been a practical problem for the log engineers to recognize the fluid type of reservoirs and reduce cost.The former indicators of gas reservoir recognition are too simple and easily affected by lithology. With the data of drilling, well logging, well testing and geology, this thesis researches on these aspects:①Full sonic waveform analysis techniques based on Slowness-Time Correlation(STC), and extract the slowness of compressional wave and shear wave;②The extraction of stoneley wave and research on the permeability;③The calculation of rock mechanic parameters based on shear wave logging data;④Research on the gas sensitive parameters, and build the index to recognize the gas reservoirs;⑤Gas reservoirs recognition based on WaveSonic/XMAC data。Major conclusions are summarized below:(1) Diploe shear wave logging data has the features of large quantity and high resolution. Based on the slowness of compressional wave, shear wave and stoneley wave, rock mechanic parameters is obtained. It is able to evaluate the reservoirs’oil-bearing properties.(2) Stoneley wave is sensitive to the permeability of formation. The fluid mobility (QFM) relationship with core analysis, testing, production logging data is built.(3) In rock mechanic parameters, while the gas saturation increases, the fluid compressibility increases and the Poisson ratio decreases. The gas reservoir recognition method could be built with this characteristic.(4) The gas reservoir recognition charts are built:①The central, west, south and east areas gas recognition charts of Sulige;②The east of Ordos Basin quartz sandstone gas recognition charts.Through the above researches on a series of models, methods and data processing, etc, an application software including dipole shear wave logging data processing, permeability calculating, and gas reservoirs recognition has been programmed, which could provide reliable decisions for production field.