Logging Fluid Identification And Evaluation For Extra Heavy Oil Reservoirs

The Venezuela Hu CC area super-oil reservoir is a terrestrial river-delta deposit with shallow reservoir depth and lithologic loose sandstone with high porosity,high permeability and high saturation.Due to the continuous bifurcation and consolidation of continental rivers,the reservoir sand bodies undergo rapid phase transition,and the interlayers are very developed and have strong heterogeneity.In the nature of reservoir fluids,crude oil has the characteristics of high density,high viscosity,and relatively high ratio of dissolved gas to oil.It is a type of oily oil that is rich in foam oil.Surface water intrusion not only makes water more complex,but also increases the viscosity and density of crude oil..However,shallow depth of reservoirs,loose lithology,and large borehole diameters lead to poor logging accuracy.In addition,the data of cores and well logs in the early stage were relatively small,which seriously affected the in-depth evaluation of the well logging system of the Hu CC District's over-heavy oil reservoirs.Therefore,compared with the domestic heavy oil reservoirs,the Hu CC District super-heavy oil reservoirs have significant differences in core characteristics,reservoir characteristics,fluid properties,and wellbore conditions.At present,relatively mature logging evaluation technologies in China cannot fully meet the needs of the early stage of development such as improving the interpretation compliance rate,large-scale deployment of horizontal wells and pilot tests in a cost-effective manner.There is an urgent need to conduct research on identification and evaluation of well logging fluids in over-heavy oil reservoirs under the R&D overseas operation mode.In this paper,the problems in the logging evaluation of the overweight oil reservoir in the Hu-Cong area are analyzed by analyzing the core experimental data,test production test data,logging data,and geological data,using core statistical methods,core-scale logging methods,etc.The lithology,physical properties,pore structure,oil-bearing properties,fluid properties,seepage characteristics,and wettability of shallow super-oil reservoirs in the Hu-C Block were established,and the mudstones suitable for the Hu-CC area super-heavy oil reservoirs were established.Computational models for wells,seepages,saturations,etc.,combined with data such as test oil production tests,studies on fluid identification methods for unconsolidated oil reservoirs with loose sandstone,etc.,establishes a systematic comprehensive logging evaluation technique for superheavy oil reservoirs,and finally combines macroscopic depositions.Micro-phase and single-well fine processing interpretation results,etc.,multi-well comparative analysis was conducted,and the distribution of oil and water in the super-heavy oil reservoirs in the Hu-CC area was summarized.Finally,it achieved the improvement of logging interpretation level for unconsolidated oil reservoirs with loose sandstone,improved the accuracy of geological parameters such as pores,seepage,and saturation,provided geological parameters for the deployment of horizontal wells in the Hu CC area,and provided effective for the pilot test of the Hu-CC area.Well logging technology guarantee and basis.