Shiyou shiyan dizhi (Jan 2024)
Preliminary application and prospect of well site determination technology of gaseous hydrocarbon in continental shale cores
Abstract
Fluid analysis of continental shale formations is an important basis for the evaluation of shale oil sweet spots. In view of the characteristics that gaseous hydrocarbons in core samples are easy to lose and the needs of shale oil drilling site, a device and method for rapid collection and determination of gaseous hydrocarbons in cores at well site are developed, and a rapid method for calculating apparent gas-oil ratio (AGOR) and estimating free oil loss based on gaseous hydrocarbon analysis and pyrolysis oil content analysis data of cores is discussed. The research shows that the device is suitable for the detection of gaseous hydrocarbons in full-diameter cores and bulk samples. It can not only realize the collection and determination of gaseous hydrocarbons in full-diameter cores at normal temperature and pressure, but also determine the total amount of gaseous hydrocarbons in bulk core samples. The relative error of gaseous hydrocarbon determination is 10%, and the test results can be converted into gaseous hydrocarbon content per unit mass of rock samples. The full-diameter core escape gas analysis can realize the non-destructive collection and determination of gaseous hydrocarbons in the cores, which reflects the change characteristics of vertical oil and gas bearing and heterogeneity of shale formations. AGOR can reflect the trend of oil-gas bearing and flowability of shale formations, and the higher AGOR, the better the flowability of shale oil of corresponding shale formations. AGOR can be used to estimate the loss of free hydrocarbon in the process of pressure and temperature reduction degassing, which has great application potential in establishing the recovery method of the loss of free hydrocarbon in the process of core temperature and pressure reduction degas-sing. The core gas hydrocarbon determination technology enriches the experimental technical means and methods of core fluid analysis suitable for well sites, and provides data support for fluid evaluation and sweet spot determination of continental shale formations.
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