气测录井资料在南海西部油田随钻测井解释中的应用

Application of Mud Gas Logging Data in LWD Interpretation in Western Area of South China Sea

摘要: 南海西部海域随着勘探实践的不断深入，常规随钻测井解释方法在储层评价方面遇到了诸多困难。气测录井是在随钻中实时录取的反映地下储层含油气性的直接资料，南海西部油田识别油气层较实用的方法主要有皮克斯勒解释法、轻烃比值法、三角形图版法、轻/重烃值法等。对比分析气测资料和测井资料的特点，研究出气测、测井综合解释图版法，主要包括总烃体积分数 − 烃平衡(φ(TG) − B_H)、总烃体积分数 − C₁/C₂+的体积分数比(φ(TG) − φ(C₁)/φ(C₂₊))、总烃体积分数 − 烃湿度(φ(TG) − W_H)、烃湿度 − 电阻率(W_H − ρ_t)、总烃体积分数 − 补偿中子孔隙度(φ(TG) − φ_nc)、声波时差/(密度 × 补偿中子孔隙度) − (C₁ + C₂)的体积分数之和(Δt/(ρ × φ_nc) − (φ(C₁) + φ(C₂)))等交会图版，以及气测总烃与测井电阻率优化后连续交会法等，在南海西部探井、评价井以及开发井的测井储层评价中得到了广泛应用。

Abstract: With the continuous deepening of exploration in the west area of South China Sea, conventional LWD interpretation encountered many challenges in reservoir evaluation. Mud gas log collected the direct data reflecting oil and gas bearing property of the reservoir while drilling. Practical methods identifying oil and gas layer in this area included Plixer interpretation method, light hy-drocarbon ratio method, triangle plot method and light/heavy hydrocarbon ratio method. Composite gas logging and log interpretation plots are worked out by comparing the characteristics of gas logging and well log data. These plots include φ(TG) − B_H, φ(TG) − φ(C₁)/φ(C₂₊), φ(TG) − W_H, W_H − ρ_t, φ(TG) − φ_nc, Δt/(ρ × φ_nc) − (φ(C₁) + φ(C₂)). These methods have been widely used in well log reservoir prediction in exploration well, appraisal well and production well in the western area of South China Sea.