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Study And Application Of Lost Circulation Resistance And Control Technology During Drilling

Posted on:2008-02-18Degree:DoctorType:Dissertation
Country:ChinaCandidate:K H LvFull Text:PDF
GTID:1101360218463229Subject:Oil-Gas Well Engineering
Abstract/Summary:PDF Full Text Request
Lost circulation is one of the most serious drilling troubles that affect drilling safety, because it not only brings loss to drilling engineering, but also impacts exploration and development of oil&gas resources. This paper is concerned with the outstanding problems that exist in lost circulation resistance and control technology during drilling. Lost circulation simulation equipment and assessment technology , lost circulation position locating technology and new lost circulation resistance and control agents were studied.According to the problems of the present lost circulation simulation equipments, HTHP lost circulation simulation equipment was developed. It is used to evaluate dynamic or static sealing capability of lost circulation control agents for man-made core sample, natural core sample and steel block with fracture(working temperature is between room temperature to 180℃, working pressure is between zero to 40MPa, shear rate is between zero to 1000 s-1),it can also measure the pressure-bearing capability of sealed formation. Experiment results indicated that this lost circulation simulation equipment possesses good accuracy and is reliable, experimental results will be more guidable for field operations as well.Based on the analysis of different locating lost circulation position methods, the method of stand pipe pressure variation is used. According to the problems, such as flow accuracy, open hole irregular and complex calculation, calculation formula and procedure were founded, the methods of measuring key parameters were developed, and the software was worked out accordingly. This software has good user interface and its operation is simple. This software was used in two wells.In view of the limitations of traditional bridging type lost circulation materials, the new technology of auto-adapting lost circulation resistance and control was put forward. The materials, such as elastic solid material, micell polymer and filling & strengthening material were synthesized or selected. Based on these materials, auto-adapting lost circulation resistance and control agents and drilling fluid were developed. The experimental results and field applications showed that auto-adapting lost circulation resistance and control drilling fluid can effectively prevent and control lost circulation, improve pressure-bearing capability of lost circulation formation.Self-bonding chemical lost circulation agent was prepared. It can react in water, its reaction products fill between particles and cement the particles together. The cementing rate and compressive strength of cementing body was affected by reaction time, particle size and added additives. The cementing body of self-bonding chemical lost circulation material has some permeability and the permeability can be adjusted, so it can be used to control lost circulation in reservoir.
Keywords/Search Tags:Lost circulation, evaluation method, lost circulation formation position, auto-adjusting lost circulation resistance and control agent, self-bonding chemical lost circulation agent
PDF Full Text Request
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