Lateral contrast and prediction of carboniferous reservoirs using logging data in Tahe oilfield, Xinjiang, China

Abstract

Valuable industrial oil and gas were discovered in the formations of Ordovician, Carboniferous and Triassic of the Tahe (塔河) oilfield, Xinjiang (新疆), China. The Carboniferous formations contain several oil- and gas-bearing layers. The lateral distribution of Carboniferous reservoir is unstable, and thin layers are crossbedded. This makes it difficult to do lateral formations’ contrast and reservoir prediction, so it is necessary to develop a method that can achieve reservoir lateral contrast and prediction by using multi-well logging data and seismic data. To achieve reservoir lateral contrast and prediction at the Carboniferous formations of the Tahe oilfield, processing and interpretation of logging data from a single well were done first. The processing and interpretation include log pretreatment, environmental correction and computation of reservoir’s parameters (porosity, clay content, water saturation, etc.). Based on the previous work, the data file of logging information of multi-well was formed, and then the lateral distribution pictures (2D and 3D pictures of log curves and reservoir parameters) can be drawn. Comparing multi-well’s logging information, seismic profiles and geological information (sedimentary sign), the reservoir of the Carboniferous in the Tahe oilfield can be contrasted and predicted laterally. The sand formation of Carboniferous can be subdivided. The results of reservoir contrast and prediction of the Carboniferous formations show that 2D and 3D pictures of multi-well reservoir parameters make the lateral distribution of reservoir and oil-bearing sand very clear, the connectedness of the reservoir of neighboring wells can be analyzed, and five sand bodies can be identified based on the reservoir’s lateral distribution, geological information and seismic data.