Given paper describes how integration of different methods such as core data, well logs, production logging, seismic data and well test analysis was used to solve the problem with determination of gas accumulation boundaries in sediment complex PK1-3 of the Field M. Given work is devoted to the block with wells 2,36,49,85,127,148 of the field, since it is characterized by high uncertainty, sc. recently drilled wells 1V, 2V and 120 have produced oil although according to present day geological concept they were considered to be gas saturated in intervals investigated by production logging. Besides well 127, which was presumably oil saturated, has produced gas. Accounting mismatching production data and geological concept the author has supposed that PK1-3 gas accumulation is characterized by more complex structure than it was supposed by predeccesors and it is represented by reservoir compartmentalization and high heterogeneity. Therefore the main aim of work was to revise distribution of gas saturated reservoir within PK1-3 sediment complex. To reach the aim the author has set the following tasks: to revise geological correlation and gas oil contact; to carry out fault interpretation by means of seismic and well test data; to determine areal facies distribution on the base of integrated core, log motifs and seismic facies analysis. Thus, estimation of gas saturated reservoir portion was realized by two stages: defining the boundary of gas accumulation in depth on the base of well logs, production data and fault interpretation; reservoir distribution determination on the base of seismic facies analysis within derived gas accumulation boundary.