Research On Evaluation And Method Of Horizontal Well Drilling Difficulty Based On Regional Statistical Data

Horizontal wells have become an important means of efficient development in complex conditions such as low permeability oil and gas reservoirs and old oilfields.The difficulty of horizontal well drilling may vary due to factors such as well depth,length of horizontal section,slope formation rate,and offset distance.It is necessary to establish a reasonable quantitative evaluation system for horizontal well construction difficulty.At the drilling design stage,based on the historical data that has been drilled,quantitative difficulty evaluations are conducted for horizontal well drilling operations in different blocks and different well types to guide production organization and optimize the operation process.Therefore,in this paper,aiming at the main difficulties in horizontal well drilling operations,in-depth research has been conducted on the difficulty evaluation methods for horizontal wells.The main work of this paper is as follows:1.Based on the statistics of horizontal well drilling data in a domestic block,the evaluation factors of horizontal well drilling construction difficulty are clarified.It is pointed out that the technical difficulties in horizontal well drilling mainly include strong formation abrasiveness,poor stability,high friction and torque during drilling,unstable wellbore trajectory,difficulty in accurate control,and difficulty in cementing.Six categories and 17 subcategories of difficulty evaluation indicators including basic data,wellbore structure,cementing data,trajectory parameters,timeliness,and block difficulty empirical values have been determined.2.A quantitative comprehensive evaluation method for horizontal well drilling difficulty based on Analytical Hierarchy Process(AHP)and fuzzy comprehensive evaluation is proposed.The specific idea is as follows: First,use AHP to construct a hierarchical structure of difficulty factors,and rely on experts to determine the weight of single factor issues;Secondly,through statistical analysis of regional data and fuzzy comprehensive evaluation,the difficulty of single factor is determined,and the membership vector of single factor difficulty is determined based on the membership function;Finally,the drilling difficulty of horizontal wells is quantitatively evaluated based on the weight and membership vector of the single factor difficulty.Based on the Java development platform,a software system for evaluating the difficulty of horizontal well drilling operations has been developed,with AHP and fuzzy comprehensive evaluation as the core,database and case base as the data support,and difficulty factor analysis and difficulty evaluation as the main line.