Evaluation Method and Application of Coring Difficulty Index in the Bohai Oilfield

Bohai Oilfield has a large number of coring operations every year, and has formed a fixed operation mode. The success rate, quality and timeliness of coring need to be further improved. In order to solve these three problems, we have studied and analyzed the results of 238 well times and 9282 coring in Bohai Oilfield in the past four years, studied the influence of geological factors, operation factors and instrument factors on coring, proposed the evaluation method of coring success rate index and coring quality index, and established an evaluation system for evaluating coring success rate and coring quality from logging data according to this law. Relying on this system, we applied this evaluation system to 40 wells and 1295 coring from September to December 2022, and relied on this evaluation system to provide reasonable coring methods, thus improving the success rate of coring, and controlling the key operating conditions in the coring process, improving the quality of coring and improving the timeliness of coring.