新景煤矿保安区煤体结构特征及测井模型构建

Characteristics of coal structure and construction of well logging model in Baoan block of Xinjing Mine

煤体结构是制约构造煤发育区煤层气勘探开发的重要地质约束条件,对煤体结构的精确判识是优化煤层气开发方案的基础。为了明确新景煤矿保安区煤体结构发育规律,采用定性与定量相结合的方法对测井曲线进行整理分析,结果表明:在定性分析阶段,自然伽马、密度、井径2、深双侧向电阻率和声波时差对煤体结构的变化响应强烈,基本能反映出煤体结构的变化规律;在定量分析阶段,通过对钻井所取煤样进行GSI赋值、单因素多因素线性回归分析及相对误差分析验证,构建了一套适合于新景煤矿保安区的煤体结构测井模型。通过研究,明确了新景煤矿保安区的煤体结构的发育规律,认为8#煤层Ⅰ、Ⅱ、Ⅲ类煤分别占净煤总厚度的36.16%、30.51%、33.33%,15#煤层Ⅰ、Ⅱ、Ⅲ类煤分别占28.43%、50.73%、20.84%,从Ⅲ类煤占比的角度认为15#煤层煤体结构略优于8#煤层。

Coal structure is an important geological constraint for the exploration and development of coalbed methane in tectonic coal development area.Accurate identification of coal structure is the basis for optimizing the development plan of coalbed methane.In order to clarify the development rule of coal structure in the Baoan block of Xinjing Coal Mine,the logging curves were sorted out and analyzed by combining qualitative and quantitative methods.The results show that in the qualitative analysis stage,natural gamma ray,density,borehole diameter 2,deep investigate double lateral resistivity log and acoustic time difference have strong response to the change of coal structure,which basically reflects the change law of coal structure;in the quantitative analysis stage,through GSI assignment,single factor and multi-factor linear regression analysis and relative error analysis verification of the coal samples taken from drilling,a set of coal structure logging model suitable for the Baoan block of Xinjing Coal Mine is constructed.Based on the study,the development law of coal structure in the Baoan block of Xinjing Coal Mine has been defined.It is considered that the coal structure of ClassⅠ,ClassⅡand ClassⅢin No.8 coal seam accounts for 36.16%,30.51%and 33.33%of the total thickness of net coal respectively,the coal structure of ClassⅠ,ClassⅡand ClassⅢin No.15 coal seam accounts for 28.43%,50.73%and 20.84%respectively.In terms of property of ClassⅢcoal,the coal structure of No.15 coal seam is slightly better than that of No.8 coal seam.