Research On The Optimization Of Rod Pump System And Equipment Adaptability Based On Multiple Working Conditions

CBM well drainage equipment is the key to complete the CBM extraction work,and the optimal design of the drainage equipment selection is an important factor for the safe and reasonable,continuous and stable,economical and efficient production of CBM wells.In this paper,by studying the reservoir water production law and inflow dynamic characteristics of CBM wells,at the same time,it analyzes the characteristics of drainage and gas recovery of CBM wells and takes common drainage equipment as well as its characteristics as the basic research object.It aims at the development of CBM well drainage equipment for selection of mismatch and inapplicability,as well as the mismatch between the working parameters of the drainage equipment and the production demand.Research on the water production law and inflow dynamic characteristics of the coalbed methane reservoir,the selection and optimization of the rod pump system,the analysis and calculation of the conditions for carrying pulverized coal in the wellbore,and the adaptability analysis of extraction equipment under low-yield conditions that is carried out.This subject has been supported by a major national science and technology project: Large-scale oil and gas field and coalbed methane development "Research and application demonstration of adaptive control technology for drainage based on wellbore flow field"(project number: 2017ZX05064004001)project.First of all,this paper studies the water production law of coalbed methane reservoirs,analyzes the expansion law of the pressure drop funnel shape in the early stage of single well drainage,and obtains the water production prediction model,combining the permeability changes before and after the reservoir reform and the basic parameters.The water production prediction model is calculated and analyzed,and the inflow dynamics under different permeability and boundary sealing rates are studied and analyzed,which provides a basis for the selection of drainage technology and drainage equipment.Secondly,the rod pump system is selected as the research object,combined with the actual production conditions of the coalbed methane well,the optimization design model of the rod pump system is established,and the system optimization principle is determined as follows: water production,downpump depth,etc.as a reference for equipment selection index,to optimize the selection and optimization of the rod pump system;at the same time,according to the motor power and drag ability,the main reference indicators for the reasonable selection of the motor model are given,and the selection and optimization of the rod pump and ground equipment under normal working conditions are completed.Then,according to the special working conditions of pulverized coal production,the pulverized coal discharge conditions and the pulverized coal discharge rate are studied and analyzed,and the relationship between the critical liquid flow velocity and the pulverized coal discharge rate and the rod diameter and pipe diameter under the pulverized coal discharge conditions is obtained,and comparing and analyzing the system parameter optimization schemes to improve the pulverized coal carrying effect and improving the pulverized coal problem;at the same time,to address the current adaptability of drainage equipment in low-efficiency well areas,and combine the resource conditions and output conditions of the CBM well block and other productivity factors,using the multi-level fuzzy evaluation method,the adaptability analysis of common equipment such as "three pumping equipment",screw pumps,electric submersible pumps,jet pumps,etc.is carried out,and the equipment selection scheme based on the water production volume as a reference index is given.Finally,based on theoretical research,an expert system for the selection and optimization of rod pumps for coal-bed methane wells and equipment evaluation was compiled using VB language,and the previous version of the software was improved,which improved the efficiency of field equipment selection and design as well as the adaptability of equipment.