Application Of Acoustic Image Logging Of The Ordovician Carbonate Reservoir’s Evaluation In The Northern Tarim Basin

Most of the petroleum and gas originate from carbonate formation in many large oil fields are productive wells. The fracture is the important path of filtration and accumulated space in carbonate formation, however, there are many special characters of carbonate formation,such as aeolotropism and anisotropy, increaseing the difficulties of exploration.Ordovician carbonate reservoir space types is based with dissolution caves,holes and crack in Tarim Basin Halahatang-Xinken areas,sewing the main fracture system communication between the reservoir within a certain range. Reservoir heterogeneity is strong on the overall,lithologic traps is the formation of a number of relatively independent systems.Relying on conventional logging technology has been difficult to meet the needs of the area carbonate reservoir evaluation, must be fully integrated with the evaluation of new logging technology in order to better reservoir evaluated.Array acoustic data of dipole acoustic imaging logging data containe the formation of acoustic parameters (velocity, attenuation, anisotropy, etc.), full-wave analysis to extract the acoustic parameters, can more accurately determine the mechanical stratigraphy of the oil reserves,acoustic, rock physical properties, and thus on the formation evaluation.The artical is based on previous human research to solve geological problems for the purpose of the study area, geological data, drilling data, logging data, on the basis of detailed analysis of carbonate chimney hole reservoir reservoir characteristics, and acid pressure testing data collection and sorting on the basis of the summary of the logging response characteristics of the different reservoir types; the dipole sonic log data were processed to extract the carbonate strata of the compressinal wave, shear wave, Stoneley wave transit time, the calculated reflection coefficient and energy of the Stoneley wave attenuation. Stoneley wave reflection and energy attenuation could judge the validity of the reservoir.It will explain the results with conventional logging data, and electronic imaging logging data processing and interpretation of results combined with a comprehensive analysis, and acid fracturing oil test data to verify the interpretation of results. The following conclusions:(1) The dipole sonic log data processing in Halahatang-xinken area, and testing data comparison showed that the dipole sonic log data can be used to evaluate the effectiveness of the reservoir. Its reservoir used to evaluate the effectiveness of energy of Stoneley wave attenuation to determine, the attenuation curve from wells segment base value, the greater the reservoir, the better. Under normal circumstances, the attenuation curve value fluctuations to reach1db/ft or above, the reflection coefficient in the corresponding wells abnormal response characteristics of the more obvious, indicating that the reservoir better.(2) Using Stoneley wave energy attenuation or reflection coefficient to determine the reservoir would be effected of the borehole wall mud cake. The formation of the sidewall cake is related with drilled reservoir and the length of measuring dipoles time interval, impacting the energy attenuation of the Stoneley wave of the reservoir effectiveness of evaluation. It should be as short as possible to drilling into the reservoir of time and the measurement of dipole acoustic time interval of well-logging.(3) Stoneley wave reflection coefficient have cracks, holes, stratigraphic surfaces and caliper change response, and good correlation between the decay curves and energy. When the well section there are cracks, holes, but the Stoneley wave energy attenuation curve and the reflection coefficient is no response, they have to consider the borehole wall is there are mud cake, and in combination with conventional logging data, electrical imaging logging data processing the results were analyzed to determine the reservoir validity.(4) The stoneley wave energy attenuation was effected by the hole diameter, lithology changes. When hole enlargement or lithology changes, the reflection coefficient of the Stoneley wave have abnormal response and the energy decay curve value fluctuations, the dipole sonic log data indicates the effective reservoir. Therefore, Stoneley reservoir effectiveness should be combined with conventional and electrical imaging log data with a comprehensive judgment analysis.